@article {3083, title = {Realization of portable room temperature nanodiamond 13C hyperpolarizer}, year = {Submitted}, author = {A. Ajoy and R. Nazaryan and E. Druga and K. Liu and B. Han and J.T. Oon and M. Gierth and R. Tsang and J.H. Walton and C.A. Meriles and J.A. Reimer and D. Suter and A. Pines} } @article {3170, title = {Dynamics of frequency-swept nuclear spin optical pumping in powdered diamond at low magnetic fields}, journal = {Proceedings of the National Academy of Science}, year = {2019}, month = {01/2019}, abstract = {

A broad effort is underway to improve the sensitivity of NMR through the use of dynamic nuclear polarization. Nitrogen vacancy (NV) centers in diamond offer an appealing platform because these paramagnetic defects can be optically polarized efficiently at room temperature. However, work thus far has been mainly limited to single crystals, because most polarization transfer protocols are sensitive to misalignment between the NV and magnetic field axes. Here we study the spin dynamics of NV\−13C pairs in the simultaneous presence of optical excitation and microwave frequency sweeps at low magnetic fields. We show that a subtle interplay between illumination intensity, frequency sweep rate, and hyperfine coupling strength leads to efficient, sweep-direction-dependent 13C spin polarization over a broad range of orientations of the magnetic field. In particular, our results strongly suggest that finely tuned, moderately coupled nuclear spins are key to the hyperpolarization process, which makes this mechanism distinct from other known dynamic polarization channels. These findings pave the route to applications where powders are intrinsically advantageous, including the hyperpolarization of target fluids in contact with the diamond surface or the use of hyperpolarized particles as contrast agents for in vivo imaging.

}, issn = {0027-8424}, doi = { https://doi.org/10.1073/pnas.1811994116 }, url = {https://www.pnas.org/content/early/2019/01/23/1811994116}, author = {P.R. Zangara and S. Dhomkar and A. Ajoy and K. Liu and R. Nazaryan and D. Pagliero and D. Suter and J. Reimer and A. Pines and C. Meriles} } @article {3228, title = {Indirect Detection of Short-lived Hydride Intermediates of Iridium N-Heterocyclic Carbene Complexes via Chemical Exchange Saturation Transfer (CEST) Spectroscopy}, journal = {The Journal of Physical Chemistry C}, year = {2019}, month = {06/2019}, abstract = {

For the first time, chemical exchange saturation transfer (CEST) nuclear magnetic resonance (NMR) is utilized to study short-lived hydride intermediates in the catalytic cycle of an organometallic complex [Ir(IMes)(Py)3(H)2]Cl. These complexes are typically not observable by other NMR techniques because they are low concentrated and undergo reversible ligand exchange with the main complex. The intermediatecomplexes [Ir(Cl)(IMes)(Py)2(H)2] and [Ir(CD3OD)(IMes)(Py)2(H)2]are detected, assigned, and characterized in solution, in situ and at room temperature. Understanding the spin dynamics in these complexes is necessary for enhancing the performance of the nuclear spin hyperpolarization technique signal amplification by reversible exchange. By eliminating [Ir(Cl (IMes)(Py)2(H)2] and manipulating the spin system by radiofrequency irradiation, the nuclear spin singlet lifetime of the hydride protons was increased by more than an order of magnitude, from 2.2 \± 0.1 to 27.2 \± 1.2 s. Because of its simplicity and ability to unravel unobservable chemical species, the utilized CEST NMR approach has a large application potential for studying short-lived hydride intermediates incatalytic reactions.

}, doi = {https://doi.org/10.1021/acs.jpcc.9b04179}, url = {https://pubs.acs.org/doi/10.1021/acs.jpcc.9b04179$\#$}, author = {Stephan Knecht and Sara Hadjiali and Danila A Barskiy and Alexander Pines and Grit Sauer and Alexey Kiryutin and Konstantin Ivanov and Alexandra Yurkovskaya and Gerd Buntkowsky} } @article {2981, title = {Wide dynamic range magnetic field cycler: Harnessing quantum control at low and high fields}, journal = {Review of Scientific Instruments }, volume = {90}, year = {2019}, month = {01/2019}, abstract = {

We describe the construction of a fast field cycling device capable of sweeping a 4-order-of-magnitude range of magnetic fields, from \∼1 mT to 7 T, in under 700 ms, and which is further extendable to a 1 nT-7 T range. Central to this system is a high-speed sample shuttling mechanism between a superconducting magnet and a magnetic shield, with the capability to access arbitrary fields in between with high resolution. Our instrument serves as a versatile platform to harness the inherent dichotomy of spin dynamics on offer at low and high fields\—in particular, the low anisotropy, fast spin manipulation, and rapid entanglement growth at low field as well as the long spin lifetimes, spin specific control, and efficient inductive measurement possible at high fields. Exploiting these complementary capabilities in a single device opens up applications in a host of problems in quantum control, sensing, and information storage, besides in nuclear hyperpolarization, relaxometry, and imaging. In particular, in this paper, we focus on the ability of the device to enable low-field hyperpolarization of 13C nuclei in diamond via optically pumped electronic spins associated with nitrogen vacancy defect centers.

}, doi = {https://doi.org/10.1063/1.5064685}, url = {https://aip.scitation.org/doi/10.1063/1.5064685}, author = {A. Ajoy and X. Lv and E. Druga and K. Liu and B. Safvati and A. Morabe and M. Fenton and R. Nazaryan and S. Patel and T. Sjolander and J. Reimer and D Sakellariou and C. Meriles and A. Pines} } @article {2980, title = {Enhanced dynamic nuclear polarization via swept microwave frequency combs}, journal = {Proc. Natl. Acad. Sci}, year = {2018}, month = {10/2018}, abstract = {

Dynamic nuclear polarization (DNP) has enabled enormous gains in magnetic resonance signals and led to vastly accelerated NMR/MRI imaging and spectroscopy. Unlike conventional cw-techniques, DNP methods that exploit the full electron spectrum are appealing since they allow direct participation of all electrons in the hyperpolarization process. Such methods typically entail sweeps of microwave radiation over the broad electron linewidth to excite DNP but are often inefficient because the sweeps, constrained by adiabaticity requirements, are slow. In this paper, we develop a technique to overcome the DNP bottlenecks set by the slow sweeps, using a swept microwave frequency comb that increases the effective number of polarization transfer events while respecting adiabaticity constraints. This allows a multiplicative gain in DNP enhancement, scaling with the number of comb frequencies and limited only by the hyperfine-mediated electron linewidth. We demonstrate the technique for the optical hyperpolarization of 13C nuclei in powdered microdiamonds at low fields, increasing the DNP enhancement from 30 to 100 measured with respect to the thermal signal at 7T. For low concentrations of broad linewidth electron radicals [e.g., TEMPO ((2,2,6,6-tetramethylpiperidin-1-yl)oxyl)], these multiplicative gains could exceed an order of magnitude.

}, doi = {1807125115}, url = {https://doi.org/10.1073/pnas.1807125115}, author = {Ashok Ajoy and Kristina Liu and Xudong Lv and Raffi Nazaryan and G.Wang and E . Druga and Jeff Reimer and Ditter Suter and C. Ramanathan and C.A Meriles and Alexander Pines} } @article {3196, title = {Hyperpolarized NMR Spectroscopy: d-DNP, PHIP, and SABRE Techniques}, journal = {Chemistry - An Aisan Journal}, volume = {13}, year = {2018}, month = {08/2018}, abstract = {

The intensity of NMR signals can be enhanced by several orders of magnitude by using various techniques for the hyperpolarization of different molecules. Such approaches can overcome the main sensitivity challenges facing modern NMR/magnetic resonance imaging (MRI) techniques, whilst hyperpolarized fluids can also be used in a variety of applications in material science and biomedicine. This Focus Review considers the fundamentals of the preparation of hyperpolarized liquids and gases by using dissolution dynamic nuclear polarization (d-DNP) and parahydrogen-based techniques, such as signal amplification by reversible exchange (SABRE) and parahydrogen-induced polarization (PHIP), in both heterogeneous and homogeneous processes. The various new aspects in the formation and utilization of hyperpolarized fluids, along with the possibility of observing NMR signal enhancement, are described.

}, doi = {10.1002/asia.201800551}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/asia.201800551}, author = {Kirill Kovtunov and Ekaterina Pokochueva and Oleg Salnikov and Samuel Cousin and Dennis Kurzbach and Basile Vuichoud and Sami Jannin and Eduard Chekmenev and Boyd Goodson and Danila Barskiy and Igor Koptyug} } @article {2979, title = {Orientation independent room-temperature optical 13C hyperpolarization in powdered diamond}, journal = {Science Advances}, volume = {4}, year = {2018}, month = {05/2018}, abstract = {

Dynamic nuclear polarization via contact with electronic spins has emerged as an attractive route to enhance the sensitivity of nuclear magnetic resonance beyond the traditional limits imposed by magnetic field strength and temperature. Among the various alternative implementations, the use of nitrogen vacancy (NV) centers in diamond\—a paramagnetic point defect whose spin can be optically polarized at room temperature\—has attracted widespread attention, but applications have been hampered by the need to align the NV axis with the external magnetic field. We overcome this hurdle through the combined use of continuous optical illumination and a microwave sweep over a broad frequency range. As a proof of principle, we demonstrate our approach using powdered diamond with which we attain bulk 13C spin polarization in excess of 0.25\% under ambient conditions. Remarkably, our technique acts efficiently on diamond crystals of all orientations and polarizes nuclear spins with a sign that depends exclusively on the direction of the microwave sweep. Our work paves the way toward the use of hyperpolarized diamond particles as imaging contrast agents for biosensing and, ultimately, for the hyperpolarization
of nuclear spins in arbitrary liquids brought in contact with their surface.

}, doi = {10.1126/sciadv.aar5492 }, url = {http://advances.sciencemag.org/content/4/5/eaar5492}, author = {Ashok Ajoy and Kristina Liu and Raff Nazaryan and Xudong Lv and Pablo R. Zangara and Benjamin Safvati and Guoqing Wang and Daniel Arnold and Grace Li and Arthur Lin and Priyanka Raghavan and Emanuel Druga and Siddharth Dhomkar and Daniela Pagliero and Jeffrey A. Reimer and Dieter Suter and Carlos A. Meriles and Alexander Pines} } @article {2963, title = {Rapid Catalyst Capture Enables Metal-Free para-Hydrogen-Based Hyperpolarized Contrast Agents}, journal = {The Journal of Physical Chemistry Letters}, volume = {9}, year = {2018}, month = {05/2018}, pages = {2721{\textendash}2724}, abstract = {

Hyperpolarization techniques based on the use of\ para-hydrogen provide orders of magnitude signal enhancement for magnetic resonance spectroscopy and imaging. The main drawback limiting widespread applicability of\ para-hydrogen-based techniques in biomedicine is the presence of organometallic compounds (the polarization transfer catalysts) in solution with hyperpolarized contrast agents. These catalysts are typically complexes of platinum-group metals, and their administration in vivo should be avoided. Herein, we show how extraction of a hyperpolarized compound from an organic phase to an aqueous phase combined with a rapid (less than 10 s) Ir-based catalyst capture by metal scavenging agents can produce pure\ para-hydrogen-based hyperpolarized contrast agents, as demonstrated by high-resolution nuclear magnetic resonance (NMR) spectroscopy and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The presented methodology enables fast and efficient means of producing pure hyperpolarized aqueous solutions for biomedical and other uses.

}, doi = {10.1021/acs.jpclett.8b01007}, url = {https://pubs.acs.org/doi/abs/10.1021/acs.jpclett.8b01007}, author = {Danila A Barskiy and Lucia A Ke and Xingyang Li and Vincent Stevenson and Nevin Widarman and Hao Zhang and Ashley Truxal and Alexander Pines} } @article {3195, title = {Selective Single-Site Pd-In Hydrogenation Catalyst for Production of Enhanced Magnetic Resonance Signals using Parahydrogen}, journal = {Chemistry - A European Journal}, volume = {24}, year = {2018}, month = {01/2018}, chapter = {2547}, abstract = {

Pd\−In/Al2O3\ single-site catalyst was able to show high selectivity (up to 98\ \%) in the gas phase semihydrogenation of propyne. Formation of intermetallic Pd\−In compound was studied by XPS during reduction of the catalyst. FTIR\−CO spectroscopy confirmed single-site nature of the intermetallic Pd\−In phase reduced at high temperature. Utilization of Pd\−In/Al2O3\ in semihydrogenation of propyne with parahydrogen allowed to produce \≈3400-fold NMR signal enhancement for reaction product propene (polarization=9.3\ \%), demonstrating the large contribution of pairwise hydrogen addition route. Significant signal enhancement as well as the high catalytic activity of the Pd\−In catalyst allowed to acquire\ 1H MR images of flowing hyperpolarized propene gas selectively for protons in CH, CH2\ and CH3\ groups. This observation is unique and can be easily transferred to the development of a useful MRI technique for an in situ investigation of selective semihydrogenation in catalytic reactors.

}, doi = {10.1002/chem.201705644}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/chem.201705644}, author = {Dudari Burueva and Kirill Kovtunov and Andrey Bukhtiyarov and Danila Barskiy and Igor Prosvirin and Igor Mashkovsky and Galina Baeva and Valerii Bukhtiyarov and Aleksandr Stakheev and Igor Koptyug} } @article {2421, title = {13C-Decoupled J-Coupling Spectroscopy Using Two-Dimensional Nuclear Magnetic Resonance at Zero-Field}, journal = {The Journal of Physical Chemistry Letters}, volume = {8}, year = {2017}, pages = {1512-1516}, author = {Sjolander, TF and Tayer, MCD and Kentner, A and Budker, D and Pines, A} } @article {2422, title = {Antisymmetric Couplings Enable Direct Observation of Chirality in Nuclear Magnetic Resonance Spectroscopy}, journal = {The Journal of Physical Chemistry Letters}, volume = {8}, year = {2017}, pages = {710-714}, author = {King, JP and Sjolander, TF and Blanchard, JW} } @article {2812, title = {Distance-dependent magnetic resonance tuning as a versatile MRI sensing platform for biological targets}, journal = {Nature Materials}, volume = {16}, year = {2017}, pages = {537 - 542}, chapter = {537}, author = {Choi, J.-S. and Kim, S. and Yoo, D. and Shin, T.-H. and Kim, H. and Gomes, M.D. and Kim, S. H. and Pines, A. and Cheon, J.} } @article {2699, title = {Invited Review Article: Instrumentation for nuclear magnetic resonance in zero and ultralow magnetic field}, journal = {Review of Scientific Instruments}, volume = {88}, year = {2017}, month = {09/2017}, abstract = {

We review experimental techniques in our laboratory for nuclear magnetic resonance (NMR) in zero and ultralow magnetic field (below 0.1 μT) where detection is based on a low-cost, non-cryogenic, spin-exchange relaxation free 87Rb atomic magnetometer. The typical sensitivity is 20-30 fT/Hz1/2 for signal frequencies below 1 kHz and NMR linewidths range from Hz all the way down to tens of mHz. These features enable precision measurements of chemically informative nuclear spin-spin couplings as well as nuclear spin precession in ultralow magnetic fields.

}, doi = {https://doi.org/10.1063/1.5003347}, url = {http://aip.scitation.org/doi/abs/10.1063/1.5003347}, author = {Tayler, MCD and Theis, Thomas and Tobias F. Sjolander and John W. Blanchard and Kentner, A and Pustelny, S and Pines, Alexander and Budker, Dmitry} } @article {2391, title = {An optimized microfabricated platform for the optical generation and detection of hyperpolarized 129Xe}, journal = {Scientific Reports }, year = {2017}, url = {http://www.nature.com/articles/srep43994}, author = {Daniel J. Kennedy and Scott J. Seltzer and Ricardo Jimenez-Martinez and Hattie L. Ring and Nicholas Malecek and Svenja Knappe and Elizabeth Donley and John Kitching and Vikram S. Bajaj and Alexander Pines} } @article {1867, title = {129Xe NMR Relaxation-Based Macromolecular Sensing}, journal = {JACS Communication}, volume = {138}, year = {2016}, month = {07/2016}, chapter = {9747}, author = {Muller Gomes and Phuong Dao and Keunghong Jeong and Clancy Slack and Christophoros Vassiliou and Matthew B. Francis and David Wemmer and Alexander Pines} } @article {1955, title = {Nondisruptive Dissolution of Hyperpolarized 129Xe into Viscous Aqueous and Organic Liquid Crystalline Environments}, journal = {Angewandte Chemie }, year = {2016}, type = {Communication}, author = {AE Truxal and CC Slack and MD Gomes and CC Vassiliou and DE Wemmer and A Pines} } @article {2420, title = {Nuclear magnetic resonance at millitesla fields using a zero-field spectrometer}, journal = {Journal of Magnetic Resonance}, volume = {270}, year = {2016}, pages = {35-39}, author = {Tayler, MCD and Sjolander, TF and Pines, A and Budker, D} } @article {2297, title = {Rotaxane probes for protease detection by 129Xe hyperCEST NMR}, journal = {Chemical Communications}, year = {2016}, month = {12/2016}, doi = {10.1039/C6CC09302G}, author = {Slack, CS and Finbloom, JA and Jeong, K and Bruns, CJ and Wemmer, DE and Pines, A and Francis, MB} } @article {1941, title = {Rotaxane-mediated suppression and activation of cucurbit[6]uril for molecular detection by 129Xe hyperCEST NMR}, journal = {ChemComm}, year = {2016}, author = {Joel A. Finbloom and Clancy C. Slack and Carson J. Bruns and Keunhong Jeong and David E. Wemmer and Alexander Pines and Matthew B. Francis} } @article {2074, title = {Targeted Molecular Imaging of Cancer Cells using MS2-Based 129Xe NMR}, journal = {Bioconjugate Chemistry}, volume = {27}, year = {2016}, month = {07/2016}, chapter = {1796}, doi = {10.1021/acs.bioconjchem.6b00275}, url = {http://pubs.acs.org/doi/abs/10.1021/acs.bioconjchem.6b00275}, author = {Keunhong Jeong and Chawita Netirojjanakul and Henrik K Munch and Jinny Sun and Joel A Finbloom and David E Wemmer and Alexander Pines and Matthew B Francis} } @article {2070, title = {Transition-Selective Pulses in Zero-Field Nuclear Magnetic Resonance}, journal = {The Journal of Physical Chemistry}, volume = {120}, year = {2016}, month = {05/2016}, chapter = {4343}, doi = {10.1021/acs.jpca.6b04017}, url = {http://pubs.acs.org/doi/abs/10.1021/acs.jpca.6b04017}, author = {Sjolander, TF and Tayler, M and King, JP and Budker, D and Pines, A} } @article {1866, title = {Investigation of DOTA-Metal Chelation Effects on 129Xe Chemical Shift}, journal = {ChemPhysChem}, year = {2015}, author = {Keunhong Jeong and Clancy C. Slack and Christophoros C. Vassiliou and Phuong Dao and Muller D Gomes and Daniel J. Kennedy and Ashley E. Truxal and Lindsay J Sperling and Matthew B. Francis and David E. Wemmer and Alexander Pines} } @article {1924, title = {~Measurement of untruncated nuclear spin interactions via zero-to ultralow-field nuclear magnetic resonance}, journal = {Physical Review B}, year = {2015}, author = {John W. Blanchard and Tobias F. Sjolander and Jonathan P. King and Micah Ledbetter and Emma H. Levine and Vikram S. Bajaj and Dmitri Budker and Alexander Pines} } @article {1875, title = {Room temperature in situ nuclear spin hyperpolarization from optically pumped nitrogen vacancy centers in diamond}, journal = {Nature Communications}, year = {2015}, author = {Jonathan P. King and Keunhong Jeong and Christophoros C. Vassiliou and Chang S. Shin and Ralph H. Page and Claudia E. Avalos and Hai-Jing Wang and Alexander Pines} } @article {1627, title = {Zero-field nuclear magnetic resonance spectroscopy of viscous liquids}, journal = {Journal of Magnetic Resonance}, volume = {250}, year = {2015}, month = {01/2015}, pages = {1-6}, doi = {Doi:10.1016/j.jmr.2014.10.012}, author = {Shimizu, Y. and Blanchard, J.W. and Pustelny, S. and Saielli, G. and Bagno, A. and Ledbetter, M.P. and Budker, D. and Pines, A.} } @article {1474, title = {Genetically encoded reporters for hyperpolarized xenon MRI}, journal = {Nature Chemistry}, volume = {6}, year = {2014}, month = {04/2014}, pages = {629-634}, chapter = {629}, doi = {10.1038/nchem.1934 }, author = {Mikhail G. Shapiro and R. Matthew Ramirez and Lindsay J. Sperling and George Sun and Jinny Sun and Alexander Pines and David V. Schaffer and Vikram S. Bajaj} } @article {1478, title = {Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip}, journal = {Nature Communication}, volume = {5}, year = {2014}, pages = {3908}, doi = {10.1038/ncomms4908}, author = {Jimenez-Martinez, R. and Kennedy, D. J. and Rosenbluh, M. and Donley, E. A. and Knappe, S. and Seltzer, S. J. and Ring, H. and Bajaj, V.S. and Kitching, J.} } @article {1476, title = {Optically detected cross-relaxation spectroscopy of electron spins in diamonds}, journal = {Nature Communication}, volume = {5}, year = {2014}, month = {06/2014}, pages = {4135}, doi = {10.1038/ncomms5135}, author = {Wang, H. J. and Shin, C. S. and Seltzer, S. J. and Avalos, C. E. and Pines, A. and Bajaj, V. S.} } @article {1477, title = {Optically-detected nuclear quadrupolar interaction of 14N in nitrogen-vacancy centers in diamond}, journal = {Physical Review B}, volume = {89}, year = {2014}, pages = {205202}, doi = {10.1103/PhysRevB.89.205202}, author = {Shin, C. S. and Butler, M. C. and Wang, H. J. and Avalos, C. E. and Seltzer, S. J. and Liu, R. and Pines, A. and Bajaj, V.S.} } @article {1475, title = {Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Optical Magnetometer (Cover Article)}, journal = {Angewandte Chemie}, volume = {53}, year = {2014}, month = {09/2014}, pages = {1-6}, doi = {DOI: 10.1002/anie.201403416}, author = {Ganssle, P. J. and Shin, H. D. and Seltzer, S. J. and Bajaj, V.S. and Ledbetter, M. P. and Budker, D. and Knappe, S. and Kitching, J. and Pines, A} } @article {245, title = {Fundamental Aspects of Parahydrogen Enhanced Low-Field Nuclear Magnetic Resonance}, journal = {Physical Review Letters}, volume = {110}, year = {2013}, note = {Phys Rev Lett113RITimes Cited:0Cited References Count:28}, month = {Mar 26}, pages = {137602}, abstract = {

We report new phenomena in low-field H-1 nuclear magnetic resonance (NMR) spectroscopy using parahydrogen induced polarization (PHIP), enabling determination of chemical shift differences, delta nu, and the scalar coupling constant J. NMR experiments performed with thermal polarization in millitesla magnetic fields do not allow the determination of scalar coupling constants for homonuclear coupled spins in the inverse weak coupling regime (delta nu \< J). We show here that low-field PHIP experiments in the inverse weak coupling regime enable the precise determination of delta nu and J. Furthermore we experimentally prove that observed splittings are related to delta nu in a nonlinear way. Naturally abundant C-13 and Si-29 isotopes lead to heteronuclear J-coupled H-1-multiplet lines with amplitudes significantly enhanced compared to the amplitudes for thermally prepolarized spins. PHIP-enhanced NMR in the millitesla regime allows us to measure characteristic NMR parameters in a single scan using samples containing rare spins in natural abundance. DOI: 10.1103/PhysRevLett.110.137602

}, keywords = {exchange}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.110.137602}, url = {://WOS:000316685100032}, author = {Colell, J. and Turschmann, P. and Gloggler, S. and Schleker, P. and Theis, T. and Ledbetter, M. and Budker, D. and Pines, A. and Blumich, B. and Appelt, S.} } @article {243, title = {HyperCEST detection of a 129Xe-based contrast agent composed of cryptophane-A molecular cages on a bacteriophage scaffold}, journal = {Magnetic Resonance in Medicine}, volume = {69}, year = {2013}, pages = {1245-1252}, author = {Stevens, T.K. and Palaniappan, K.K. and Ramirez, R.M. and Francis, M.B. and Wemmer, D.E. and Pines, A.} } @article {1350, title = {Hyperpolarized xenon-based molecular sensors for label-free detection of analytes}, journal = {Journal of the American Chemical Society}, volume = {136}, year = {2013}, month = {12/2013}, pages = {164-168}, doi = {10.1021/ja406760r}, author = {Garimella, Praveena and Meldrum, Tyler and Witus, Leah Suzanne and Smith, Monica and Bajaj, Vikram and Wemmer, David E. and Francis, Matthew B. and Pines, Alexander} } @article {1095, title = {Nanoemulsion contrast agents with sub-picomolar sensitivity for xenon NMR}, journal = {Journal of the American Chemical Society}, year = {2013}, month = {06/2013}, doi = {10.1021/ja402885q}, author = {Stevens, T. K. and Ramirez, R. M. and Pines, A.} } @article {1074, title = {Sensitive magnetic control of ensemble nuclear spin hyperpolarization in diamond}, journal = {Nature Communications}, volume = {4}, year = {2013}, note = {Nature communicationsWang, Hai-JingShin, Chang SAvalos, Claudia ESeltzer, Scott JBudker, DmitryPines, AlexanderBajaj, Vikram SengEngland2013/06/06 06:00Nat Commun. 2013 Jun 5;4:1940. doi: 10.1038/ncomms2930.}, month = {June 5, 2013}, pages = {1940}, chapter = {1940}, abstract = {

Dynamic nuclear polarization, which transfers the spin polarization of electrons to nuclei, is routinely applied to enhance the sensitivity of nuclear magnetic resonance. This method is particularly useful when spin hyperpolarization can be produced and controlled optically or electrically. Here we show complete polarization of nuclei located near optically polarized nitrogen-vacancy centres in diamond. Close to the ground-state level anti-crossing condition of the nitrogen-vacancy electron spins, (13)C nuclei in the first shell are polarized in a pattern that depends sensitively upon the magnetic field. Based on the anisotropy of the hyperfine coupling and of the optical polarization mechanism, we predict and observe a reversal of the nuclear spin polarization with only a few millitesla change in the magnetic field. This method of magnetic control of high nuclear polarization at room temperature can be applied in sensitivity enhanced nuclear magnetic resonance of bulk nuclei, nuclear-based spintronics, and quantum computation in diamond.

}, isbn = {2041-1723 (Linking)}, doi = {10.1038/ncomms2930}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23736952}, author = {Wang, H. J. and Shin, C. S. and Avalos, C. E. and Seltzer, S. J. and Budker, D. and Pines, A. and Bajaj, V. S.} } @article {1318, title = {Suppression of electron spin decoherence of the diamond NV center by a transverse magnetic field}, journal = {Physical Review B}, volume = {88}, year = {2013}, month = {10/2013}, abstract = {

We demonstrate that the spin decoherence of nitrogen vacancy (NV) centers in diamond can be suppressed by a transverse magnetic field if the electron spin bath is the primary decoherence source. The NV spin coherence, created in \“a decoherence-free subspace,\” is protected by the transverse component of the zero-field splitting, increasing the spin-coherence time about twofold. The decoherence due to the electron spin bath is also suppressed at magnetic fields stronger than \∼25 G when applied parallel to the NV symmetry axis. Our method can be used to extend the spin-coherence time of similar spin systems for applications in quantum computing, field sensing, and other metrologies.

}, doi = {10.1103/PhysRevB.88.161412}, url = {http://prb.aps.org/abstract/PRB/v88/i16/e161412}, author = {Shin, Chang S. and Avalos, Claudia E. and Butler, Mark C. and Wang, Hai-Jing and Seltzer, Scott J. and Liu, Ren-Bao and Pines, Alexander and Bajaj, Vikram S.} } @article {249, title = {Room-temperature operation of a radiofrequency diamond magnetometer near the shot-noise limit}, journal = {Journal of Applied Physics}, volume = {112}, year = {2012}, note = {J Appl Phys061ECTimes Cited:1Cited References Count:15}, month = {Dec 15, 2012}, pages = {124519}, chapter = {124519}, abstract = {

We operate a nitrogen-vacancy (NV-) diamond magnetometer at ambient temperatures and study the dependence of its bandwidth on experimental parameters including optical and microwave excitation powers. A model based on the Bloch equations is used to analyze the NV center\&$\#$39;s response time, tau, during continuous optical and microwave irradiation, and tau(-1) is shown to be a weighted average of T-1(-1) and T-2(-1), where T-1 and T-2 are the longitudinal and transverse relaxation times of the electron spin during optical irradiation. We measured a maximum detection bandwidth of similar to 1.6 MHz with optical excitation intensity of similar to 2.3MW/cm(2), limited by the available optical power. The sensitivity of the NV ensemble for continuous-wave magnetometry in the presence of photon shot noise is analyzed. Two detection schemes are compared, one involving modulation of the fluorescence by an oscillating magnetic field while the microwave frequency is held constant, and the other involving double modulation of the fluorescence when the microwave frequency is modulated during the detection. For the first of these methods, we measure a sensitivity of 4.6 +/- 0.3 nT/root Hz, unprecedented in a detector with this active volume of similar to 10 mu m(3) and close to the photon-shot-noise limit of our experiment. The measured bandwidth and sensitivity of our device should allow detection of micro-scale NMR signals with microfluidic devices. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4771924]

}, keywords = {spin}, isbn = {0021-8979}, doi = {Doi 10.1063/1.4771924}, url = {http://link.aip.org/link/doi/10.1063/1.4771924}, author = {Shin, C. S. and Avalos, C. E. and Butler, M. C. and Trease, D. R. and Seltzer, S. J. and Mustonen, J. P. and Kennedy, D. J. and Acosta, V. M. and Budker, D. and Pines, A. and Bajaj, V. S.} } @article {248, title = {Zero-Field NMR Enhanced by Parahydrogen in Reversible Exchange}, journal = {Journal of the American Chemical Society}, volume = {134}, year = {2012}, note = {J Am Chem Soc909GLTimes Cited:2Cited References Count:40}, month = {02/2012}, pages = {3987-3990}, abstract = {

We have recently demonstrated that sensitive and chemically specific NMR spectra can be recorded in the absence of a magnetic field using hydrogenative parahydrogen induced polarization (PHIP)(1-3) and detection with an optical atomic magnetometer. Here, we show that non-hydrogenative para-hydrogen-induced polarization(4-6) (NH-PHIP) can also dramatically enhance the sensitivity of zero-field NMR. We demonstrate the detection of pyridine, at concentrations as low as 6 mM in a sample volume of 250 mu L, with sufficient sensitivity to resolve all identifying spectral features, as supported by numerical simulations. Because the NH-PHIP mechanism is nonreactive, operates in situ, and eliminates the need for a prepolarizing magnet, its combination with optical atomic magnetometry will greatly broaden the analytical capabilities of zero-field and low-field NMR.

}, keywords = {gas}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja2112405}, url = {://WOS:000301550800015}, author = {Theis, T. and Ledbetter, M. P. and Kervern, G. and Blanchard, J. W. and Ganssle, P. J. and Butler, M. C. and Shin, H. D. and Budker, D. and Pines, A.} } @article {254, title = {Remotely Detected NMR for the Characterization of Flow and Fast Chromatographic Separations Using Organic Polymer Monoliths}, journal = {Analytical Chemistry}, volume = {83}, year = {2011}, note = {Anal Chem798ZVTimes Cited:4Cited References Count:35}, month = {Aug 1}, pages = {6004-6010}, abstract = {

An application of remotely detected magnetic resonance imaging is demonstrated for the characterization of flow and the detection of fast, small molecule separations within hypercrosslinked polymer monoliths. The hyper-cross-linked monoliths exhibited excellent ruggedness, with a transit time relative standard deviation of less than 2.1\%, even after more than 300 column volumes were pumped through at high pressure and flow. Magnetic resonance imaging enabled high. resolution intensity and velocity-encoded images of mobile phase flow through the monolith. The images confirm that the presence of a polymer monolith within the capillary disrupts the parabolic laminar flow profile that is characteristic of mobile phase flow within an open tube. As a result, the mobile phase and analytes are equally distributed in the radial direction throughout the monolith. Also, in-line monitoring of chromatographic separations of small molecules at high flow rates is shown. The coupling of monolithic chromatography columns and NMR provides both real-time peak detection and chemical shift information for small aromatic molecules. These experiments demonstrate the unique power of magnetic resonance, both direct and remote, in studying chromatographic processes.

}, keywords = {visualization}, isbn = {0003-2700}, doi = {Doi 10.1021/Ac2010108}, url = {://WOS:000293252500029}, author = {Teisseyre, T. Z. and Urban, J. and Halpern-Manners, N. W. and Chambers, S. D. and Bajaj, V. S. and Svec, F. and Pines, A.} } @article {260, title = {Investigation of antirelaxation coatings for alkali-metal vapor cells using surface science techniques}, journal = {Journal of Chemical Physics}, volume = {133}, year = {2010}, note = {J. Chem. Phys.ISI Document Delivery No.: 667NNTimes Cited: 6Cited Reference Count: 81Seltzer, S. J. Michalak, D. J. Donaldson, M. H. Balabas, M. V. Barber, S. K. Bernasek, S. L. Bouchiat, M. -A. Hexemer, A. Hibberd, A. M. Kimball, D. F. Jackson Jaye, C. Karaulanov, T. Narducci, F. A. Rangwala, S. A. Robinson, H. G. Shmakov, A. K. Voronov, D. L. Yashchuk, V. V. Pines, A. Budker, D.Office of Science, Office of Basic Energy Sciences, Materials Sciences Division and Nuclear Science Division, of the U. S. Department of Energy [DE-AC02-05CH11231]; NSF/DST [PHY-0425916]; Office of Naval Research (ONR) [N0001409WX21049]The authors thank Daniel Fischer, Kristin Schmidt, and Ed Kramer for assistance with the NEXAFS measurements, and Joel Ager, Joshua Wnuk, David Trease, and Gwendal Kervern for helpful discussions and other assistance. S.J.S., D.J.M., M. H. D., A. P., and D. B., the Advanced Light Source, and the DSC, FTIR, and AFM studies were supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences Division and Nuclear Science Division, of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231 at Lawrence Berkeley National Laboratory. Other parts of this work were funded by the NSF/DST under Grant No. PHY-0425916 for U.S.-India cooperative research, by an Office of Naval Research (ONR) MURI grant, and by ONR under Grant No. N0001409WX21049.AMER INST PHYSICSMELVILLE}, month = {October 11, 2010}, pages = {144703}, type = {Article}, chapter = {144703}, abstract = {

Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10 000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of CvC double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials. (C) 2010 American Institute of Physics. [doi:10.1063/1.3489922]

}, keywords = {SPECTROSCOPY}, isbn = {0021-9606}, doi = {10.1063/1.3489922}, url = {http://link.aip.org/link/doi/10.1063/1.3489922}, author = {Seltzer, S. J. and Michalak, D. J. and Donaldson, M. H. and Balabas, M. V. and Barber, S. K. and Bernasek, S. L. and Bouchiat, M. A. and Hexemer, A. and Hibberd, A. M. and Kimball, D. F. J. and Jaye, C. and Karaulanov, T. and Narducci, F. A. and Rangwala, S. A. and Robinson, H. G. and Shmakov, A. K. and Voronov, D. L. and Yashchuk, V. V. and Pines, A. and Budker, D.} } @article {261, title = {MRI Thermometry Based on Encapsulated Hyperpolarized Xenon}, journal = {Chemphyschem}, volume = {11}, year = {2010}, note = {Chemphyschem691LFTimes Cited:2Cited References Count:25}, month = {Nov 15}, pages = {3529-3533}, abstract = {

A new approach to MRI thermometry using encapsulated hyperpolarized xenon is demonstrated The method is based on the temperature dependent chemical shift of hyperpolarized xenon in a cryptophane-A cage This shift is linear with a slope of 029 ppm degrees C(-1) which is perceptibly higher than the shift of the proton resonance frequency of water (ca 0 01 ppm degrees C(-1)) that is currently used for MRI thermometry Using spectroscopic imaging techniques, we collected temperature maps of a phantom sample that could discriminate by direct NMR detection between temperature differences of 0 1 degrees C at a sensor concentration of 150 mu M Alternatively, the xenon-in-cage chemical shift was determined by indirect detection using saturation transfer techniques (Hyper-CEST) that allow detection of nanomolar agent concentrations Thermometry based on hyperpolarized xenon sensors improves the accuracy of currently available MRI thermometry methods, potentially giving rise to biomedical applications of biosensors functionalized for binding to specific target molecules

}, keywords = {xe-129}, isbn = {1439-4235}, doi = {Doi 10.1002/Cphc.201000507}, url = {://WOS:000285080600023}, author = {Schilling, F. and Schroder, L. and Palaniappan, K. K. and Zapf, S. and Wemmer, D. E. and Pines, A.} } @article {263, title = {A Xenon-Based Molecular Sensor Assembled on an MS2 Viral Capsid Scaffold}, journal = {Journal of the American Chemical Society}, volume = {132}, year = {2010}, note = {J Am Chem Soc589OATimes Cited:20Cited References Count:23}, month = {May 5}, pages = {5936-+}, abstract = {

In MRI, anatomical structures are most often differentiated by variations in their bulk magnetic properties. Alternatively, exogenous contrast agents can be attached to chemical moieties that confer affinity to molecular targets; the distribution of such contrast agents can be imaged by magnetic resonance. Xenon-based molecular sensors are molecular imaging agents that rely on the reversible exchange of hyperpolarized xenon between the bulk and a specifically targeted host-guest complex. We have incorporated similar to 125 xenon sensor molecules in the interior of an MS2 viral capsid, conferring multivalency and other properties of the viral capsid to the sensor molecule. The resulting signal amplification facilitates the detection of sensor at 0.7 pM, the lowest to date for any molecular imaging agent used in magnetic resonance. This amplification promises the detection of chemical targets at much lower concentrations than would be possible without the capsid scaffold.

}, keywords = {nmr}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja100319f}, url = {://WOS:000277158500007}, author = {Meldrum, T. and Seim, K. L. and Bajaj, V. S. and Palaniappan, K. K. and Wu, W. and Francis, M. B. and Wemmer, D. E. and Pines, A.} } @article {264, title = {Xenon-based molecular sensors in lipid suspensions}, journal = {Journal of Magnetic Resonance}, volume = {205}, year = {2010}, note = {J Magn Reson627SZTimes Cited:8Cited References Count:23}, month = {Aug}, pages = {242-246}, abstract = {

There have been many proposals to use xenon-based molecular sensors in biological settings. Fundamental to understanding the properties of these sensors in vivo is characterizing their behavior in lipid environments. We report the investigation of xenon-based molecular sensors in suspensions of lipid vesicles with a size comparable to cells. We detail spectroscopic properties of sensors associated with lipid vesicles as well as those in equilibrium in the surrounding solution. We characterize the dependence of the spectral parameters on temperature, relevant for studies at physiological temperatures. We also demonstrate the ability to perform selective saturation transfer (Hyper-CEST) between sensor, both lipid bound and unbound, and the bulk solution. Lastly, we demonstrate the applicability of saturation transfer in the heterogeneous medium as an imaging modality. (C) 2010 Elsevier Inc. All rights reserved.

}, keywords = {binding}, isbn = {1090-7807}, doi = {Doi 10.1016/J.Jmr.2010.05.005}, url = {://WOS:000280064500008}, author = {Meldrum, T. and Schroder, L. and Denger, P. and Wemmer, D. E. and Pines, A.} } @article {271, title = {{\textquoteright}Ex situ{\textquoteright} magnetic resonance volume imaging}, journal = {Chemical Physics Letters}, volume = {467}, year = {2009}, note = {Chem Phys Lett386VCTimes Cited:2Cited References Count:25}, month = {Jan 5}, pages = {398-401}, abstract = {

The portable NMR community has introduced advances that have allowed for a variety of studies. Imaging of static and moving objects has almost become standardized. The inherent static field gradients of portable systems have, however, limited such studies to imaging of slices perpendicular to the main gradient; full volume imaging in transportable, open systems has not been actively pursued. We present a true three-dimensional image of a phantom in an ex situ, electromagnet-based system. The basic concepts and designs put forth here extend in a straightforward fashion to higher fields and imaging of larger samples by ex situ methodologies. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {array}, isbn = {0009-2614}, doi = {Doi 10.1016/J.Cplett.2008.11.069}, url = {://WOS:000261909700037}, author = {Demas, V. and Franck, J. M. and Bouchard, L. S. and Sakellariou, D. and Meriles, C. A. and Martin, R. and Prado, P. J. and Bussandri, A. and Reimer, J. A. and Pines, A.} } @article {281, title = {Fluid-flow characterization with nuclear spins without magnetic resonance}, journal = {Applied Physics Letters}, volume = {93}, year = {2008}, note = {Appl Phys Lett345DHTimes Cited:2Cited References Count:20}, month = {Sep 1}, abstract = {

A technique for noninvasive monitoring of flow inside metallic enclosures using laser-based atomic magnetometry is introduced. The analyte is labeled via nuclear magnetization by magnets, thereby combining the polarization and encoding steps. No radiofrequency or audiofrequency pulses are involved. We demonstrate detection of flow inside an aluminum pipe with an inner diameter of 4.9 mm that has a constriction with a diameter of 1.6 mm and a length of 6.4 mm. The results agree with a model of spin density and relaxation indicating that our technique allows for fast, quantitative, and noninvasive diagnostics of flow with potential applications discussed below. (c) 2008 American Institute of Physics.

}, keywords = {mri}, isbn = {0003-6951}, doi = {Doi 10.1063/1.2977773}, url = {://WOS:000258975800042}, author = {Crawford, C. W. and Xu, S. J. and Siegel, E. J. and Budker, D. and Pines, A.} } @article {276, title = {Temperature response of (129)Xe depolarization transfer and its application for ultrasensitive NMR detection}, journal = {Physical Review Letters}, volume = {100}, year = {2008}, note = {Phys Rev Lett320JWTimes Cited:12Cited References Count:8}, month = {Jun 27}, abstract = {

Trapping xenon in functionalized cryptophane cages makes the sensitivity of hyperpolarized (HP) (129)Xe available for specific NMR detection of biomolecules. Here, we study the signal transfer onto a reservoir of unbound HP xenon by gating the residence time of the nuclei in the cage through the temperature-dependant exchange rate. Temperature changes larger than similar to 0.6 K are detectable as an altered reservoir signal. The temperature response is adjustable with lower concentrations of caged xenon providing more sensitivity at higher temperatures. Ultrasensitive detection of functionalized cryptophane at 310 K is demonstrated with a concentration of 10 nM, corresponding to a similar to 4000-fold sensitivity enhancement compared to conventional detection. This makes HPNMR capable of detecting such constructs in concentrations far below the detection limit of benchtop uv-visible light absorbance.

}, keywords = {biosensors}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.100.257603}, url = {://WOS:000257230500066}, author = {Schroeder, L. and Meldrum, T. and Smith, M. and Lowery, T. J. and Wemmer, D. E. and Pines, A.} } @article {277, title = {Temperature-controlled molecular depolarization gates in nuclear magnetic resonance}, journal = {Angewandte Chemie-International Edition}, volume = {47}, year = {2008}, note = {Angew Chem Int Edit308BXTimes Cited:13Cited References Count:19}, pages = {4316-4320}, keywords = {mri}, isbn = {1433-7851}, doi = {Doi 10.1002/Anie.200800382}, url = {://WOS:000256364400007}, author = {Schroder, L. and Chavez, L. and Meldrum, T. and Smith, M. and Lowery, T. J. and Wemmer, D. E. and Pines, A.} } @article {279, title = {Zero-field remote detection of NMR with a microfabricated atomic magnetometer}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {105}, year = {2008}, note = {P Natl Acad Sci USA266XBTimes Cited:37Cited References Count:26}, month = {Feb 19}, pages = {2286-2290}, abstract = {

We demonstrate remote detection of nuclear magnetic resonance (NMR) with a microchip sensor consisting of a microfluidic channel and a microfabricated vapor cell (the heart of an atomic magnetometer). Detection occurs at zero magnetic field, which allows operation of the magnetometer in the spin-exchange relaxation-free (SERF) regime and increases the proximity of sensor and sample by eliminating the need for a solenoid to create a leading field. We achieve pulsed NMR linewidths of 26 Hz, limited, we believe, by the residence time and flow dispersion in the encoding region. In a fully optimized system, we estimate that for 1 s of integration, 7 x 10(13) protons in a volume of 1 mm(3), prepolarized in a 10-kG field, can be detected with a signal-to-noise ratio of approximate to 3. This level of sensitivity is competitive with that demonstrated by microcoils in 100-kG magnetic fields, without requiring superconducting magnets.

}, keywords = {mri}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0711505105}, url = {://WOS:000253469900009}, author = {Ledbetter, M. P. and Savukov, I. M. and Budker, D. and Shah, V. and Knappe, S. and Kitching, J. and Michalak, D. J. and Xu, S. and Pines, A.} } @article {288, title = {Dispersion measurements using time-of-flight remote detection MRI}, journal = {Magnetic Resonance Imaging}, volume = {25}, year = {2007}, note = {Magn Reson Imaging167BHTimes Cited:5Cited References Count:10}, month = {May}, pages = {449-452}, abstract = {

Remote detection nuclear magnetic resonance and magnetic resonance imaging can be used to study fluid flow and dispersion in a porous medium from a purely Eulerian point of view (i.e., in a laboratory frame of reference). Information about fluid displacement is obtained on a macroscopic scale in a long-time regime, while local velocity distributions are averaged out. It is shown how these experiments can be described using the common flow propagator formalism and how experimental data can be analyzed to obtain effective porosity, flow velocity inside the porous medium, fluid dispersion and flow tracing of fluid. (C) 2007 Elsevier Inc. All rights reserved.

}, keywords = {flow}, isbn = {0730-725X}, doi = {Doi 10.1016/J.Mri.2006.11.011}, url = {://WOS:000246425100004}, author = {Granwehr, J. and Harel, E. and Hilty, C. and Garcia, S. and Chavez, L. and Pines, A. and Sen, P. N. and Song, Y. Q.} } @article {286, title = {Multipole shimming of permanent magnets using harmonic corrector rings}, journal = {Review of Scientific Instruments}, volume = {78}, year = {2007}, note = {Rev Sci Instrum151WETimes Cited:8Cited References Count:8}, month = {Mar}, abstract = {

Shimming systems are required to provide sufficient field homogeneity for high resolution nuclear magnetic resonance (NMR). In certain specialized applications, such as rotating-field NMR and mobile ex situ NMR, permanent magnet-based shimming systems can provide considerable advantages. We present a simple two-dimensional shimming method based on harmonic corrector rings which can provide arbitrary multipole order shimming corrections. Results demonstrate, for example, that quadrupolar order shimming improves the linewidth by up to an order of magnitude. An additional order of magnitude reduction is in principle achievable by utilizing this shimming method for z-gradient correction and higher order xy gradients. (c) 2007 American Institute of Physics.

}, keywords = {field}, isbn = {0034-6748}, doi = {Doi 10.1063/1.2713438}, url = {://WOS:000245320800056}, author = {Jachmann, R. C. and Trease, D. R. and Bouchard, L. S. and Sakellariou, D. and Martin, R. W. and Schlueter, R. D. and Budinger, T. F. and Pines, A.} } @article {290, title = {Para-hydrogen-enhanced hyperpolarized gas-phase magnetic resonance imaging}, journal = {Angewandte Chemie-International Edition}, volume = {46}, year = {2007}, note = {Angew Chem Int Edit174ZPTimes Cited:28Cited References Count:37}, pages = {4064-4068}, keywords = {he-3}, isbn = {1433-7851}, doi = {Doi 10.1002/Anie.200700830}, url = {://WOS:000246981900008}, author = {Bouchard, L. S. and Kovtunov, K. V. and Burt, S. R. and Anwar, M. S. and Koptyug, I. V. and Sagdeev, R. Z. and Pines, A.} } @article {285, title = {Para-hydrogen-induced polarization in heterogeneous hydrogenation reactions}, journal = {Journal of the American Chemical Society}, volume = {129}, year = {2007}, note = {J Am Chem Soc160MRTimes Cited:36Cited References Count:45}, month = {May 2}, pages = {5580-5586}, abstract = {

We demonstrate the creation and observation of para-hydrogen-induced polarization in heterogeneous hydrogenation reactions. Wilkinson\&$\#$39;s catalyst, RhCl(PPh3)(3), supported on either modified silica gel or a polymer, is shown to hydrogenate styrene into ethylbenzene and to produce enhanced spin polarizations, observed through NMR, when the reaction was performed with H-2 gas enriched in the para spin isomer. Furthermore, gaseous phase para-hydrogenation of propylene to propane with two catalysts, the Wilkinson\&$\#$39;s catalyst supported on modified silica gel and Rh(cod)(sulfos) (cod = cycloocta-1,5-diene; sulfos = -O3S(C6H4)CH2C(CH2PPh2)(3)) supported on silica gel, demonstrates heterogeneous catalytic conversion resulting in large spin polarizations. These experiments serve as a direct verification of the mechanism of heterogeneous hydrogenation reactions involving immobilized metal complexes and can be potentially developed into a practical tool for producing catalyst-free fluids with highly polarized nuclear spins for a broad range of hyperpolarized NMR and MRI applications.

}, keywords = {alignment}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja068653o}, url = {://WOS:000245946400064}, author = {Koptyug, I. V. and Kovtunov, K. V. and Burt, S. R. and Anwar, M. S. and Hilty, C. and Han, S. I. and Pines, A. and Sagdeev, R. Z.} } @article {295, title = {Diastereomeric Xe chemical shifts in tethered cryptophane cages}, journal = {Journal of the American Chemical Society}, volume = {128}, year = {2006}, note = {J Am Chem Soc118KQTimes Cited:14Cited References Count:42}, month = {Dec 27}, pages = {16980-16988}, abstract = {

Cryptophane cages serve as host molecules to a Xe atom. Functionalization of cryptophane-A has permitted the development of Xe as a biosensor. Synthetic routes used to prepare cryptophanes result in racemic mixtures of the chiral cages. In the preparation of a tethered cryptophane-A cage for biosensor applications, some achiral and chiral substituents such as left-handed amino acids have been used. When the substituent is achiral, the NMR signal of the Xe atom in the functionalized cage in solution is a single isotropic peak, since the Xe shielding tensor components in the R and L cages differ by no more than the signs of the off-diagonal elements. Chiral substituents can split the cage-encapsulated Xe NMR signal into one or more sets of doublets, depending on the number of asymmetric centers in the substituent. We carry out quantum mechanical calculations of Xe nuclear magnetic shielding for the Xe atom at the same strategic position within an L cryptophane-A cage, under the influence of chiral potentials that represent for r or I substituents outside the cage. Calculations of the Xe shielding response in the Lr and LI diastereomeric pairs permit the prediction of the relative order of the Xe chemical shifts in solutions containing the RI and LI diastereomers. Where the substituent itself possesses two chiral centers, comparison of the calculated isotropic shielding responses in the Llr, Lrl, RIl, and Lrr systems, respectively, permits the prediction of the Xe spectrum of diastereomeric systems in solutions containing Llr, RIr, LIl, and RIl systems. Assignment of the peaks observed in the experimental Xe NMR spectra is therefore possible, without having to undertake the difficult synthetic route that produces a single optically pure enantiomer.

}, keywords = {chirality}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja066661z}, url = {://WOS:000242941600104}, author = {Ruiz, E. J. and Sears, D. N. and Pines, A. and Jameson, C. J.} } @article {294, title = {Molecular imaging using a targeted magnetic resonance hyperpolarized biosensor}, journal = {Science}, volume = {314}, year = {2006}, note = {Science096MWTimes Cited:109Cited References Count:20}, month = {Oct 20}, pages = {446-449}, abstract = {

A magnetic resonance approach is presented that enables high-sensitivity, high-contrast molecular imaging by exploiting xenon biosensors. These sensors link xenon atoms to specific biomolecular targets, coupling the high sensitivity of hyperpolarized nuclei with the specificity of biochemical interactions. We demonstrated spatial resolution of a specific target protein in vitro at micromolar concentration, with a readout scheme that reduces the required acquisition time by \>3300-fold relative to direct detection. This technique uses the signal of free hyperpolarized xenon to dramatically amplify the sensor signal via chemical exchange saturation transfer (CEST). Because it is similar to 10,000 times more sensitive than previous CEST methods and other molecular magnetic resonance imaging techniques, it marks a critical step toward the application of xenon biosensors as selective contrast agents in biomedical applications.

}, keywords = {agents}, isbn = {0036-8075}, doi = {Doi 10.1126/Science.1131847}, url = {://WOS:000241382500036}, author = {Schroder, L. and Lowery, T. J. and Hilty, C. and Wemmer, D. E. and Pines, A.} } @article {302, title = {Multiphase imaging of gas flow in a nanoporous material using remote-detection NMR}, journal = {Nature Materials}, volume = {5}, year = {2006}, note = {Nat Mater029AOTimes Cited:25Cited References Count:40}, month = {Apr}, pages = {321-327}, abstract = {

Pore structure and connectivity determine how microstructured materials perform in applications such as catalysis, fluid storage and transport, filtering or as reactors. We report a model study on silica aerogel using a time-of-flight magnetic resonance imaging technique to characterize the flow field and explain the effects of heterogeneities in the pore structure on gas flow and dispersion with Xe-129 as the gas-phase sensor. The observed chemical shift allows the separate visualization of unrestricted xenon and xenon confined in the pores of the aerogel. The asymmetrical nature of the dispersion pattern alludes to the existence of a stationary and a flow regime in the aerogel. An exchange time constant is determined to characterize the gas transfer between them. As a general methodology, this technique provides insights into the dynamics of flow in porous media where several phases or chemical species may be present.

}, keywords = {visualization}, isbn = {1476-1122}, doi = {Doi 10.1038/Nmat1598}, url = {://WOS:000236530400024}, author = {Harel, E. and Granwehr, J. and Seeley, J. A. and Pines, A.} } @article {299, title = {Optimization of xenon biosensors for detection of protein interactions}, journal = {Chembiochem}, volume = {7}, year = {2006}, note = {Chembiochem003SDTimes Cited:39Cited References Count:25}, month = {Jan}, pages = {65-73}, abstract = {

Hyperpolarized Xe-129 NMR spectroscopy can detect the presence of specific low-concentration biomolecular analytes by means of a xenon biosensor that consists of a water-soluble, targeted cryptophane-A cage that encapsulates the xenon. In this work, we use the prototypical biotinylated xenon biosensor to determine the relationship between the molecular composition of the xenon biosensor and the characteristics of protein-bound resonances. The effects of diastereomer overlap, dipole-dipole coupling, chemical-shift anisotropy, xenon exchange, and biosensor conformotional exchange on the protein-bound biosensor signal were assessed. It was found that an optimal protein-bound biosensor signal can be obtained by minimizing the number of biosensor diastereomers and using a flexible linker of appropriate length. Both the line width and sensitivity of chemical shift to protein binding of the xenon biosensor were found to be inversely proportional to linker length.

}, keywords = {complexes}, isbn = {1439-4227}, doi = {Doi 10.1002/Cbic.200500327}, url = {://WOS:000234701000012}, author = {Lowery, T. J. and Garcia, S. and Chavez, L. and Ruiz, E. J. and Wu, T. and Brotin, T. and Dutasta, J. P. and King, D. S. and Schultz, P. G. and Pines, A. and Wemmer, D. E.} } @article {305, title = {Toward ex situ phase-encoded spectroscopic imaging}, journal = {Concepts in Magnetic Resonance Part B-Magnetic Resonance Engineering}, volume = {29B}, year = {2006}, note = {Concept Magn Reson B067JNTimes Cited:7Cited References Count:20}, month = {Aug}, pages = {137-144}, abstract = {

Spectroscopic imaging of a sample placed outside of both the radio frequency and the imaging gradient coils is presented. The sample is placed in a field with a permanent one-dimensional inhomogeneity. The imaging gradients used for phase encoding are designed to produce a static field that depends only on the transverse direction, uncoupling the effects associated with the single-sided nature of these coils. Two-dimensional imaging coupled with chemical shift information is obtained via the ex situ matching technique. Open-saddle geometry is used to match the static field profile for chemical shift information recovery. (C) 2006 Wiley Periodicals, Inc.

}, keywords = {probe}, isbn = {1552-5031}, doi = {Doi 10.1002/Cmr.B.20069}, url = {://WOS:000239298100004}, author = {Demas, V. and Meriles, C. and Sakellariou, D. and Han, S. I. and Reimer, J. and Pines, A.} } @article {312, title = {High-resolution nuclear magnetic resonance spectroscopy of biological tissues using projected magic angle spinning}, journal = {Magnetic Resonance in Medicine}, volume = {54}, year = {2005}, note = {Magnet Reson Med949DSTimes Cited:2Cited References Count:28}, month = {Aug}, pages = {253-257}, abstract = {

High-resolution NMR spectra of materials subject to anisotropic broadening are usually obtained by rotating the sample about the magic angle, which is 54.7 degrees to the static magnetic field. In projected magic angle spinning (p-MAS), the sample is spun about two angles, neither of which is the magic angle. This provides a method of obtaining isotropic spectra while spinning at shallow angles. The p-MAS experiment may be used in situations where spinning the sample at the magic angle is not possible due to geometric or other constraints, allowing the choice of spinning angle to be determined by factors such as the shape of the sample, rather than by the spin physics. The application of this technique to bovine tissue samples is demonstrated as a proof of principle for future biological or medical applications.

}, keywords = {field}, isbn = {0740-3194}, doi = {Doi 10.1002/Mrm.20585}, url = {://WOS:000230765700001}, author = {Martin, R. W. and Jachmann, R. C. and Sakellariou, D. and Nielsen, U. G. and Pines, A.} } @article {307, title = {NMR in rotating magnetic fields: magic-angle field spinning}, journal = {Magnetic Resonance Imaging}, volume = {23}, year = {2005}, note = {Magn Reson ImagingSp. Iss. SI920ADTimes Cited:10Cited References Count:16}, month = {Feb}, pages = {295-299}, abstract = {

Magic-angle sample spinning is one of the cornerstones in high-resolution NMR of solid and semisolid materials. The technique enhances spectral resolution by averaging away rank 2 anisotropic spin interactions, thereby producing isotropic-like spectra with resolved chemical shifts and scalar couplings. In principle, it should be possible to induce similar effects in a static sample if the direction of the magnetic field is varied (e.g., magic-angle rotation of the B-0 field). Here we will review some recent experimental results that show progress toward this goal. Also, we will explore some alternative approaches that may enable the recovery of spectral resolution in cases where the field is rotating off the magic angle. Such a possibility could help mitigate the technical problems that render difficult the practical implementation of this method at moderately strong magnetic fields. (c) 2005 Elsevier Inc. All rights reserved.

}, keywords = {samples}, isbn = {0730-725X}, doi = {Doi 10.1016/J.Mri.2004.11.067}, url = {://WOS:000228658400030}, author = {Sakellariou, D. and Meriles, C. A. and Martin, R. W. and Pines, A.} } @article {306, title = {NMR spectroscopy in inhomogeneous B-0 and B-1 fields with non-linear correlation}, journal = {Journal of Magnetic Resonance}, volume = {175}, year = {2005}, note = {J Magn Reson939CPTimes Cited:8Cited References Count:38}, month = {Jul}, pages = {1-10}, abstract = {

Resolved NMR spectra from samples in inhomogeneous B-0 and B-1 fields can be obtained with the so-called \"ex situ\" methodology, employing a train of composite or adiabatic z-rotation RF pulses to periodically refocus the inhomogeneous broadening during the detection of the time-domain signal. Earlier schemes relied on a linear correlation between the inhomogeneous B0 and B, fields. Here the pulse length, bandwidth, and amplitude of the adiabatic pulses of the hyperbolic secant type are adjusted to improve the refocusing for a setup with non-linear correlation. The field correlation is measured using a two-dimensional nutation experiment augmented with a third dimension with varying RF carrier frequency accounting for off-resonance effects. The pulse optimization is performed with a computer algorithm using the experimentally determined field correlation and a standard adiabatic z-rotation pulse as a starting point for the iterative optimization procedure. The shape of the z-rotation RF pulse is manipulated to provide refocusing for the conditions given by the sample-, magnet-, and RF-coil geometry. (c) 2005 Elsevier Inc. All rights reserved.

}, keywords = {spectra}, isbn = {1090-7807}, doi = {Doi 10.1016/J.Jmr.2005.03.006}, url = {://WOS:000230050200001}, author = {Topgaard, D. and Sakellariou, D. and Pines, A.} } @article {317, title = {NMR-based biosensing with optimized delivery of polarized Xe-129 to solutions}, journal = {Analytical Chemistry}, volume = {77}, year = {2005}, note = {Anal Chem942GLTimes Cited:30Cited References Count:37}, month = {Jul 1}, pages = {4008-4012}, abstract = {

Laser-enhanced (LE) Xe-129 nuclear magnetic resonance (NMR) is an exceptional tool for sensing extremely small physical and chemical changes; however, the difficult mechanics of bringing polarized xenon and samples of interest together have limited applications, particularly to biological molecules. Here we present a method for accomplishing solution Xe-129 biosensing based on flow (bubbling) of LE Xe-129 gas through a solution in situ in the NMR probe, with pauses for data acquisition. This overcomes fundamental limitations of conventional solution-state LE Xe-129 NMR, e.g., the difficulty in transferring hydrophobic xenon into aqueous environments, and the need to handle the sample to refresh LE Xe-129 after an observation pulse depletes polarization. With this new method, we gained a factor of \> 100 in sensitivity due to improved xenon transfer to the solution and the ability to signal average by renewing the polarized xenon. Polarized xenon in biosensors was detected at very low concentrations, \<= 250 nanomolar, while retaining all the usual information from NMR. This approach can be used to simultaneously detect multiple sensors with different chemical shifts and is also capable of detecting signals from opaque, heterogeneous samples, which is a unique advantage over optical methods. This general approach is adaptable for sensing minute quantities of xenon in heterogeneous in vitro samples, in miniaturized devices and should be applicable to certain in-vivo environments.

}, keywords = {blood}, isbn = {0003-2700}, doi = {Doi 10.1021/Ac0500479}, url = {://WOS:000230270800035}, author = {Han, S. I. and Garcia, S. and Lowery, T. J. and Ruiz, E. J. and Seeley, J. A. and Chavez, L. and King, D. S. and Wemmer, D. E. and Pines, A.} } @article {319, title = {Time-of-flight flow imaging using NMR remote detection}, journal = {Physical Review Letters}, volume = {95}, year = {2005}, note = {Phys Rev Lett955SGTimes Cited:35Cited References Count:29}, month = {Aug 12}, abstract = {

A time-of-flight imaging technique is introduced to visualize fluid flow and dispersion through porous media using NMR. As the fluid flows through a sample, the nuclear spin magnetization is modulated by rf pulses and magnetic field gradients to encode the spatial coordinates of the fluid. When the fluid leaves the sample, its magnetization is recorded by a second rf coil. This scheme not only facilitates a time-dependent imaging of fluid flow, it also allows a separate optimization of encoding and detection subsystems to enhance overall sensitivity. The technique is demonstrated by imaging gas flow through a porous rock.

}, keywords = {mri}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.95.075503}, url = {://WOS:000231247300028}, author = {Granwehr, J. and Harel, E. and Han, S. and Garcia, S. and Pines, A. and Sen, P. N. and Song, Y. Q.} } @article {310, title = {Zero- to low-field MRI with averaging of concomitant gradient fields}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {102}, year = {2005}, note = {P Natl Acad Sci USA898JKTimes Cited:18Cited References Count:22}, month = {Feb 8}, pages = {1840-1842}, abstract = {

Magnetic resonance imaging (MRI) encounters fundamental limits in circumstances in which the static magnetic field is not sufficiently strong to truncate unwanted, so-called concomitant components of the gradient field. This limitation affects the attainable optimal image fidelity and resolution most prominently in low-field imaging. in this article, we introduce the use of pulsed magnetic-field averaging toward relaxing these constraints. It is found that the image of an object can be retrieved by pulsed low fields in the presence of the full spatial variation of the imaging encoding gradient field even in the absence of the typical uniform high-field time-independent contribution. In addition, error-compensation schemes can be introduced through the application of symmetrized pulse sequences. Such schemes substantially mitigate artifacts related to evolution in strong magnetic-field gradients, magnetic fields that vary in direction and orientation, and imperfections of the applied field pulses.

}, keywords = {selection}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0409115102}, url = {://WOS:000227072900009}, author = {Meriles, C. A. and Sakellariou, D. and Trabesinger, A. H. and Demas, V. and Pines, A.} } @article {328, title = {Advances in ex-situ Nuclear Magnetic Resonance}, journal = {Comptes Rendus Physique}, volume = {5}, year = {2004}, note = {Cr Phys843JCTimes Cited:13Cited References Count:47}, month = {Apr}, pages = {337-347}, abstract = {

Nuclear Magnetic Resonance has revolutionized modern science by its precision, selectivity and non-envasiveness. From complicated biomolecules to materials, from living organisms to nanometric particles, Magnetic Resonance Imaging and Spectroscopy have provided a wealth of invaluable information. Those studies take place in the laboratory, since they require strong and extremely homogeneous superconducting magnets and this represents a major limitation for the technique. Furthermore, the size of the object or subject to study is limited since it has to fit inside the bore of the magnet. Efforts to alleviate those problems lead to the recent development of portable magnetic resonance systems. Their use remained, however, mainly qualitative, since spectroscopic information could not be recovered. We have introduced recently an approach to regain this lost spectral information even in the presence of inhomogeneous magnetic fields. Our approach is based on the matching between the effect of the radio-frequency field and the effect of the static magnetic field. Several practical implementations will be reviewed and put in perspective for their applicability and efficiency in ex-situ NMR. (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.

}, keywords = {in-vivo}, isbn = {1631-0705}, doi = {Doi 10.1016/J.Crhy.2004.03.016}, url = {://WOS:000223073800006}, author = {Sakellariou, D. and Meriles, C. A. and Pines, A.} } @article {325, title = {Development of a functionalized xenon biosensor}, journal = {Journal of the American Chemical Society}, volume = {126}, year = {2004}, note = {J Am Chem Soc872UHTimes Cited:60Cited References Count:76}, month = {Nov 24}, pages = {15287-15294}, abstract = {

NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging, and the possibility of \"remote\" amplified detection. Here, we present a detailed NMR characterization of the binding of a biotin-derivatized caged-xenon sensor to avidin. Binding of \"functionalized\" xenon to avidin leads to a change in the chemical shift of the encapsulated xenon in addition to a broadening of the resonance, both of which serve as NMR markers of ligand-target interaction. A control experiment in which the biotin-binding site of avidin was blocked with native biotin showed no such spectral changes, confirming that only specific binding, rather than nonspecific contact, between avidin and functionalized xenon leads to the effects on the xenon NMR spectrum. The exchange rate of xenon (between solution and cage) and the xenon spin-lattice relaxation rate were not changed significantly upon binding. We describe two methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. We also show that the xenon chemical shifts are distinct for xenon encapsulated in different diastereomeric cage molecules. This demonstrates the potential for tuning the encapsulated xenon chemical shift, which is a key requirement for being able to multiplex the biosensor.

}, keywords = {drug discovery}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja0483037}, url = {://WOS:000225233600051}, author = {Spence, M. M. and Ruiz, E. J. and Rubin, S. M. and Lowery, T. J. and Winssinger, N. and Schultz, P. G. and Wemmer, D. E. and Pines, A.} } @article {330, title = {High-resolution NMR of static samples by rotation of the magnetic field}, journal = {Journal of Magnetic Resonance}, volume = {169}, year = {2004}, note = {J Magn Reson830ZETimes Cited:13Cited References Count:24}, month = {Jul}, pages = {13-18}, abstract = {

Mechanical rotation of a sample at 54.7degrees with respect to the static magnetic field, so-called magic-angle spinning (MAS), is currently a routine procedure in nuclear magnetic resonance (NMR). The technique enhances the spectral resolution by averaging away anisotropic spin interactions thereby producing isotropic-like spectra with resolved chemical shifts and scalar Couplings. It should be possible to induce similar effects in a static sample if the direction of the magnetic field is varied, e.g., magic-angle rotation of the B-0 field (B-0-MAS). Here, this principle is experimentally demonstrated in a static sample of solid hyperpolarized xenon at similar to3.4mT. By extension to moderately high fields, it is possible to foresee interesting applications in situations where physical manipulation of the sample is inconvenient or impossible. Such situations are expected to arise in many cases from materials to biomedicine and are particularly relevant to the novel approach of ex situ NMR spectroscopy and imaging. (C) 2004 Elsevier Inc. All rights reserved.

}, keywords = {hz}, isbn = {1090-7807}, doi = {Doi 10.1016/J.Jmr.2004.03.023}, url = {://WOS:000222161900002}, author = {Meriles, C. A. and Sakellariou, D. and Moule, A. and Goldman, M. and Budinger, T. F. and Pines, A.} } @article {326, title = {NMR studies of C-13-iodomethane: Different behavior in thermotropic and lyotropic liquid crystals}, journal = {Journal of Physical Chemistry A}, volume = {108}, year = {2004}, note = {J Phys Chem A846BMTimes Cited:9Cited References Count:38}, month = {Aug 19}, pages = {6809-6813}, abstract = {

High-resolution NMR spectra of C-13-iodomethane dissolved in thermotropic and lyotropic liquid crystalline solvents have been used to measure H-1-H-1 and C-13-H-1 dipolar couplings. The ratio of these two couplings, which is a function of the H-C-H bond angle in C-13-iodomethane, is, in general, different from that expected from the known molecular structure; solvent-solute interactions in liquid crystalline solutions are responsible for this difference. In thermotropic liquid crystalline solutions, the apparent bond angle deviation (Deltatheta(a)) increases with decreasing molecular ordering. In contrast, in lyotropic liquid crystals, no significant spectral aberration has been observed. These results indicate a fundamental physicochemical difference between the intermolecular interactions that prevail in thermotropic and lyotropic liquid crystals.

}, keywords = {biomolecules}, isbn = {1089-5639}, doi = {Doi 10.1021/Jp047330g}, url = {://WOS:000223289700001}, author = {Shahkhatuni, A. G. and Shahkhatuni, A. A. and Panosyan, H. A. and Park, G. H. J. and Martin, R. W. and Pines, A.} } @article {327, title = {Remotely detected high-field MRI of porous samples}, journal = {Journal of Magnetic Resonance}, volume = {167}, year = {2004}, note = {J Magn Reson809KKTimes Cited:26Cited References Count:28}, month = {Apr}, pages = {282-290}, abstract = {

Remote detection of NMR is a novel technique in which an NMR-active sensor surveys an environment of interest and retains memory of that environment to be recovered at a later time in a different location. The NMR or MRI information about the sensor nucleus is encoded and stored as spin polarization at the first location and subsequently moved to a different physical location for optimized detection. A dedicated probe incorporating two separate radio frequency (RF)-circuits was built for this purpose. The encoding solenoid coil was large enough to fit around the bulky sample matrix, while the smaller detection solenoid coil had not only a higher quality factor, but also an enhanced filling factor since the coil volume comprised purely the sensor nuclei. We obtained two-dimensional (2D) void space images of two model porous samples with resolution less than 1.4 mm(2). The remotely reconstructed images demonstrate the ability to determine fine structure with image quality superior to their directly detected counterparts and show the great potential of NMR remote detection for imaging applications that suffer from low sensitivity due to low concentrations and filling factor. Published by Elsevier Inc.

}, keywords = {gas}, isbn = {1090-7807}, doi = {Doi 10.1016/J.Jmr.2003.12.018}, url = {://WOS:000220635400012}, author = {Seeley, J. A. and Han, S. I. and Pines, A.} } @article {324, title = {"Shim pulses" for NMR spectroscopy and imaging}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {101}, year = {2004}, note = {P Natl Acad Sci USA882PTTimes Cited:38Cited References Count:16}, month = {Dec 21}, pages = {17576-17581}, abstract = {

A way to use adiabatic radiofrequency pulses and modulated magnetic-field gradient pulses, together constituting a \"shim pulse,\" for NMR spectroscopy and imaging is demonstrated. These pulses capitalize on phase shifts derived from probe gradient coils to compensate for nonlinear intrinsic main magnetic field homogeneity for spectroscopy, as well as for deviations from linear gradients for imaging. This approach opens up the possibility of exploiting cheaper, less-than-perfect magnets and gradient coils for NMR applications.

}, keywords = {acquisition}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0408296102}, url = {://WOS:000225951500004}, author = {Topgaard, D. and Martin, R. W. and Sakellariou, D. and Meriles, C. A. and Pines, A.} } @article {332, title = {SQUID-detected magnetic resonance imaging in microtesla magnetic fields}, journal = {Journal of Low Temperature Physics}, volume = {135}, year = {2004}, note = {J Low Temp Phys824TWTimes Cited:37Cited References Count:34}, month = {Jun}, pages = {793-821}, abstract = {

We describe studies of nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) of liquid samples at room temperature in microtesla magnetic fields. The nuclear spins are prepolarized in a strong transient field. The magnetic signals generated by the precessing spins, which range in frequency from tens of Hz to several kHz, are detected by a low-transition temperature dc SQUID (Superconducting QUantum Interference Device) coupled to an untuned, superconducting flux transformer configured as an axial gradiometer. The combination of prepolarization and frequency-independent detector sensitivity results in a high signal-to-noise ratio and high spectral resolution (similar to 1 Hz) even in grossly inhomogeneous magnetic fields. In the NMR experiments, the high spectral resolution enables us to detect the 10-Hz splitting of the spectrum of protons due to their scalar coupling to a P-31 nucleus. Furthermore, the broadband detection scheme combined with a non-resonant field-reversal spin echo allows the simultaneous observation of signals from protons and P-31 nuclei, even though their NMR resonance frequencies differ by a factor of 2.5. We extend our methodology to MRI in microtesla fields, where the high spectral resolution translates into high spatial resolution. We demonstrate two-dimensional images of a mineral oil phantom and slices of peppers, with a spatial resolution of about 1 mm. We also image an intact pepper using slice selection, again with 1-mm, resolution. A further experiments we demonstrate T-1-contrast imaging of a water phantom, some parts of which were doped with a paramagnetic salt to reduce the longitudinal relaxation time T-1. Possible applications of this MRI technique include screening for tumors and integration with existing multichannel SQUID systems for brain imaging.

}, keywords = {mri}, isbn = {0022-2291}, doi = {Doi 10.1023/B:Jolt.0000029519.09286.C5}, url = {://WOS:000221710600023}, author = {McDermott, R. and Kelso, N. and Lee, S. K. and Mossle, M. and M{\"u}ck, M. and Myers, W. and ten Haken, B. and Seton, H. C. and Trabesinger, A. H. and Pines, A. and Clarke, J.} } @article {336, title = {Three-dimensional phase-encoded chemical shift MRI in the presence of inhomogeneous fields}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {101}, year = {2004}, note = {P Natl Acad Sci USA830EQTimes Cited:18Cited References Count:12}, month = {Jun 15}, pages = {8845-8847}, abstract = {

A pulse sequence consisting of an excitation pulse and two adiabatic full-passage pulses with scaled relative peak amplitudes is combined with phase encoding to recover chemical shift information within 3D images in a 1D inhomogeneous static magnetic field with a matched rf field gradient. The results are discussed in the context of ex situ magnetic resonance and imaging. The future directions of our research in implementing the ex situ technique in a real one-sided system are also discussed.

}, keywords = {pulses}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0403016101}, url = {://WOS:000222104900004}, author = {Demas, V. and Sakellariou, D. and Meriles, C. A. and Han, S. and Reimer, J. and Pines, A.} } @article {329, title = {Variable angle spinning (VAS) NMR study of solvent effects in liquid crystalline solutions of C-13-iodomethane}, journal = {Chemical Physics Letters}, volume = {399}, year = {2004}, note = {Chem Phys Lett874AXTimes Cited:5Cited References Count:28}, month = {Nov 21}, pages = {196-199}, abstract = {

NMR spectra of C-13-iodomethane oriented in three different liquid crystalline solvents have been collected and analyzed under spinning at various angles with respect to the static magnetic field. For each sample the ratio of homonuclear (H-1-H-1) to heteronuclear (C-13-H-1) dipolar couplings, which is a function of the geometry of the solute molecule, does not change significantly with the scaling of the dipolar couplings due to spinning at different angles. This result implies that the \&$\#$39;apparent bond angle deviations\&$\#$39; (Deltatheta(a)), previously calculated from thermotropic liquid crystals, arise from a solvent effect and are not an artifact from scaling the anisotropic interactions. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {phases}, isbn = {0009-2614}, doi = {Doi 10.1016/J.Cplett.2004.10.009}, url = {://WOS:000225324400036}, author = {Park, G. H. J. and Martin, R. W. and Sakellariou, D. and Pines, A. and Shahkhatuni, A. G. and Shahkhatuni, A. A. and Panosyan, H. A.} } @article {340, title = {Amplification of xenon NMR and MRI by remote detection}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {100}, year = {2003}, note = {P Natl Acad Sci USA709HPTimes Cited:65Cited References Count:28}, month = {Aug 5}, pages = {9122-9127}, abstract = {

A technique is proposed in which an NMR spectrum or MRI is encoded and stored as spin polarization and is then moved to a different physical location to be detected. Remote detection allows the separate optimization of the encoding and detection steps, permitting the independent choice of experimental conditions and excitation and detection methodologies. In the initial experimental demonstration of this technique, we show that taking dilute Xe-129 from a porous sample placed inside a large encoding coil and concentrating it into a smaller detection coil can amplify NMR signal. In general, the study of NMR active molecules at low concentration that have low physical filling factor is facilitated by remote detection. In the second experimental demonstration, MRI information encoded in a very low-field magnet (4-7 mT) is transferred to a high-field magnet (4.2 T) to be detected under optimized conditions. Furthermore, remote detection allows the utilization of ultrasensitive optical or superconducting quantum interference device detection techniques, which broadens the horizon of NMR experimentation.

}, keywords = {field}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.1133497100}, url = {://WOS:000184620000007}, author = {Moule, A. J. and Spence, M. M. and Han, S. I. and Seeley, J. A. and Pierce, K. L. and Saxena, S. and Pines, A.} } @article {343, title = {Applications of Laser-Polarized 129 XE NMR to Biomolecular Assays}, journal = {Magnetic Resonance Imaging}, year = {2003}, pages = {1235-1239}, doi = {10.1016/J.Mri.2003.08.025}, author = {Lowery, T.J. and Rubin, S.M. and Ruiz, E.J. and Spence, M.M. and Winssinger, N. and Schultz, P.G. and Pines, A. and Wemmer, D.E.} } @article {341, title = {Broadband phase modulation by adiabatic pulses}, journal = {Journal of Magnetic Resonance}, volume = {164}, year = {2003}, note = {J Magn Reson717NCTimes Cited:14Cited References Count:14}, month = {Sep}, pages = {177-181}, abstract = {

The use of inhomogeneous but spatially correlated static and radiofrequency (RF) magnetic fields offers a potential methodology for performing magnetic resonance spectroscopy of samples placed outside the bore of the magnet. However, its practical implementation still presents challenging problems, among them the control of nuclear spins over broad frequency offset intervals. The present study introduces an efficient method of encoding the phase of the magnetization when the variation of the static field along the sample is much larger than the RF amplitude. The procedure is based on the use of consecutively applied full-passage adiabatic pulses. The induced phase modulation is broadband and selective because it does not depend on the offset relative to the central frequency and the limits can be sharply defined. Finally, the encoded phase depends almost linearly on the local RF amplitude. All these features enable the recovery of an inhomogeneity-free spectrum with amplitudes close to the theoretically attainable maximum. Published by Elsevier Science (USA).

}, keywords = {fields}, isbn = {1090-7807}, doi = {Doi 10.1016/S1090-7807(03)00157-5}, url = {://WOS:000185095200023}, author = {Meriles, C. A. and Sakellariou, D. and Pines, A.} } @article {339, title = {High-resolution NMR correlation spectra of disordered solids}, journal = {Journal of the American Chemical Society}, volume = {125}, year = {2003}, note = {J Am Chem Soc663JYTimes Cited:70Cited References Count:46}, month = {Apr 9}, pages = {4376-4380}, abstract = {

We show how high-resolution NMR spectra can be obtained for solids for which the spectra are normally broadened due to structural disorder. The method relies on correlations in the chemical shifts between pairs of coupled spins. It is found experimentally that there are strong correlations in the chemical shifts between neighboring spins in both phosphorus-31 and carbon-13 spectra. These correlations can be exploited not only to provide resolution in two-dimensional spectra, but also to yield \"chains\" of correlated chemical shifts, constituting a valuable new source of structural information for disordered materials.

}, keywords = {SPECTROSCOPY}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja0292389}, url = {://WOS:000182003500067}, author = {Sakellariou, D. and Brown, S. P. and Lesage, A. and Hediger, S. and Bardet, M. and Meriles, C. A. and Pines, A. and Emsley, L.} } @article {338, title = {High-resolution NMR of anisotropic samples with spinning away from the magic angle}, journal = {Chemical Physics Letters}, volume = {377}, year = {2003}, note = {Chem Phys Lett714CRTimes Cited:6Cited References Count:27}, month = {Aug 15}, pages = {333-339}, abstract = {

High-resolution NMR of anisotropic samples is typically performed by spinning the sample around an axis at the magic angle of 54.7degrees with the static magnetic field. Geometric and engineering constraints often prevent spinning at this specific angle. Implementations of magic angle field rotation are extremely demanding due to power requirements or an inaccessible geometry. We present a methodology for taking the magic out of MAS while still obtaining both isotropic and anisotropic spectral information during sample spinning or field rotation at arbitrary angles. Using projected-MAS, we obtained resolved scaled isotropic chemical shifts in inhomogeneously broadened spinning samples. Published by Elsevier B.V.

}, keywords = {axis}, isbn = {0009-2614}, doi = {Doi 10.1016/S0009-2614(03)01149-7}, url = {://WOS:000184895200012}, author = {Sakellariou, D. and Meriles, C. A. and Martin, R. W. and Pines, A.} } @article {346, title = {Laser-polarized Xe-129 NMR and MRI at ultralow magnetic fields}, journal = {Journal of Magnetic Resonance}, volume = {157}, year = {2002}, note = {J Magn Reson600EJTimes Cited:23Cited References Count:25}, month = {Aug}, pages = {235-241}, abstract = {

Laser-polarized Xe-129 and a high-T-c superconducting quantum interference device (SQUID) are used to obtain magnetic resonance images in porous materials at a magnetic field of 2.3 mT, corresponding to a Larmor frequency of 27 kHz. Image resolution of 1 mm is obtained with gradients of only 1 mT/m. The resolution of xenon chemical shifts in different physicochemical environments at ultralow fields is also demonstrated. Details of the circulating flow optical pumping apparatus and the SQUID spectrometer are presented. (C) 2002 Elsevier Science (USA).

}, keywords = {atoms}, isbn = {1090-7807}, doi = {Doi 10.1006/Jmre.2002.2592}, url = {://WOS:000178377400009}, author = {Wong-Foy, A. and Saxena, S. and Moule, A. J. and Bitter, H. M. L. and Seeley, J. A. and McDermott, R. and Clarke, J. and Pines, A.} } @conference {355, title = {"Lighting Up" NMR and MRI in Colloidal and Interfacial Systems}, booktitle = {Magnetic Resonance in Colloid and Interface Sciences}, year = {2002}, month = {2002}, pages = {97-106}, publisher = {Kluwer Academic Publishers, Netherlands}, organization = {Kluwer Academic Publishers, Netherlands}, address = {St. Petersburg, Russia}, author = {Pines, A. and Logan, J.W. and Spence, M. M.}, editor = {J. Fraissard and O. Lapina, eds} } @article {356, title = {Resolved magic-angle spinning of anisotropic samples in inhomogeneous fields}, journal = {Chemical Physics Letters}, volume = {358}, year = {2002}, note = {Chem Phys Lett565JGTimes Cited:10Cited References Count:14}, month = {Jun 7}, pages = {391-395}, abstract = {

The chemical shift spectrum of a liquid embedded in a porous sample spinning at the magic angle has been recovered in the presence of static field and rf gradients. Field inhomogeneity and susceptibility broadening are averaged by a procedure that combines magic-angle turning with a train of z-rotation pulses. The experiment emulates the situation encountered in \&$\#$39;ex situ\&$\#$39; NMR in which the sample is located away from the field sources. Given the equivalence of field and sample spinning, the results suggest that the use of a rotating magnetic field and refocusing pulses might enable the study of samples such as solids or fluids in porous materials external to the magnet. (C) 2002 Elsevier Science B.V. All rights reserved.

}, keywords = {pulses}, isbn = {0009-2614}, doi = {Doi 10.1016/S0009-2614(02)00642-5}, url = {://WOS:000176365900005}, author = {Meriles, C. A. and Sakellariou, D. and Pines, A.} } @article {347, title = {Rotary resonance recoupling for half-integer quadrupolar nuclei in solid-state nuclear magnetic resonance spectroscopy}, journal = {Journal of Chemical Physics}, volume = {117}, year = {2002}, note = {J Chem Phys599CVTimes Cited:22Cited References Count:53}, month = {Oct 15}, pages = {7024-7033}, abstract = {

Investigations were made of rotary resonance recouplings (R-3) of chemical shift anisotropy (CSA), heteronuclear dipolar (HTD), and homonuclear dipolar (HMD) couplings involving half-integer quadrupolar nuclei under magic-angle sample spinning condition. Under rotary resonance conditions provided by a low amplitude rf field and a high spinning speed, the spectrum of the central transition coherence of half-integer quadrupolar nuclei shows recouplings of CSA, HTD, and HMD interactions that depend on the ratio of the rf field to the spinning speed. These new properties can be used to extract electronic and structural information about the sample that are otherwise difficult to extract in the presence of a dominant quadrupolar interaction. An average Hamiltonian theory is used to explain the recoupling properties of various interactions. Experimental implementations of the R-3 are demonstrated on model compounds with spin-3/2 systems. (C) 2002 American Institute of Physics.

}, keywords = {polarization}, isbn = {0021-9606}, doi = {Doi 10.1063/1.1506907}, url = {://WOS:000178317300016}, author = {Wi, S. and Logan, J. W. and Sakellariou, D. and Walls, J. D. and Pines, A.} } @article {349, title = {Selective excitation in dipole coupled systems}, journal = {Chemical Physics Letters}, volume = {357}, year = {2002}, note = {Chem Phys Lett558GVTimes Cited:5Cited References Count:22}, month = {May 10}, pages = {241-248}, abstract = {

In this Letter the possibility of selective excitation in coupled multispin systems is studied theoretically. A general method of transforming any selective pulse developed for uncoupled systems into a form that is selective in coupled systems is presented. This is accomplished by adding a small perturbation to a decoupling radiofrequency (RF) field. When viewed in an interaction frame given by the decoupling RF field, this method generates, in an averaged sense, a propagator similar to the propagator of uncoupled spins under a shaped RF pulse. Preliminary experimental results are presented for the case of selective excitation in proton nuclear magnetic resonance in liquid crystals. (C) 2002 Elsevier Science B.V. All rights reserved.

}, keywords = {spin-diffusion}, isbn = {0009-2614}, doi = {Doi 10.1016/S0009-2614(02)00493-1}, url = {://WOS:000175958700012}, author = {Walls, J. D. and Marjanska, M. and Sakellariou, D. and Castiglione, F. and Pines, A.} } @article {362, title = {Two-dimensional high-resolution NMR spectra in matched B-0 and B-1 field gradients}, journal = {Journal of Magnetic Resonance}, volume = {156}, year = {2002}, note = {J Magn Reson568UETimes Cited:15Cited References Count:26}, month = {May}, pages = {146-151}, abstract = {

In a recent publication we presented a method to obtain highly resolved NMR spectra in the presence of an inhomogeneous B-0 field with the help of a matched RF gradient. If RF gradient pulses are combined with \"ideal\" 90degrees pulses to form inhomogeneous z rotation pulses, the line broadening caused by the B-0 gradient can be refocused, while the full chemical shift information is maintained. This approach is of potential use for NMR spectroscopy in an inhomogeneous magnetic field produced by an \"ex-situ\" surface spectrometer. In this contribution, we extend this method toward two-dimensional spectroscopy with high resolution in one or both dimensions. Line narrowing in the indirect dimension can be achieved by two types of nutation echoes, thus leading to depth-sensitive NMR spectra with full chemical shift information. If the nutation echo in the indirect dimension is combined with a stroboscopic acquisition using inhomogeneous z-rotation pulses, highly resolved two-dimensional correlation spectra can be obtained in matched field gradients. Finally, we demonstrate that an INEPT coherence transfer from proton to carbon spins is possible in inhomogeneous B-0 fields. Thus, it is possible to obtain one-dimensional C-13 NMR spectra with increased sensitivity and two-dimensional HETCOR spectra in the presence of B-0 gradients of 0.4 mT/cm. These schemes may be of some value for ex-situ NMR analysis of materials and biological systems. (C) 2002 Elsevier Science (USA).

}, keywords = {echoes}, isbn = {1090-7807}, doi = {Doi 10.1006/Jmre.2002.2545}, url = {://WOS:000176562100016}, author = {Heise, H. and Sakellariou, D. and Meriles, C. A. and Moule, A. and Pines, A.} } @article {353, title = {Variable rotation composite pulses for high resolution nuclear magnetic resonance using inhomogeneous magnetic and radiofrequency fields}, journal = {Chemical Physics Letters}, volume = {363}, year = {2002}, note = {Chem Phys Lett591TPTimes Cited:17Cited References Count:23}, month = {Sep 2}, pages = {25-33}, abstract = {

An approach toward high-resolution NMR spectroscopy on samples located outside the physical confines of a magnet (ex situ NMR), has recently been described [C.A. Meriles, D. Sakellariou, H. Heise, A.J. Moule, A. Pines, Science 293 (2001) 82]. Nutation echoes are generated by a train of z-rotation pulses in the presence of spatially matched static and rf field gradients. These pulses were based on a combination of \&$\#$39;perfect\&$\#$39; pi/2 constant rotation composite pulses and \&$\#$39;imperfect\&$\#$39; ordinary pulses of variable length. Here we introduce a new class of \&$\#$39;self-compensated\&$\#$39; z-rotation composite pulses based only on variable rotation inversion pulses that lead to an rf dependent phase shift. Experiments and simulations show that these new pulses perform well at high B-0 gradients and require less rf power than previous schemes. (C) 2002 Elsevier Science B.V. All rights reserved.

}, keywords = {echoes}, isbn = {0009-2614}, doi = {Doi 10.1016/S0009-2614(02)01116-8}, url = {://WOS:000177896600005}, author = {Sakellariou, D. and Meriles, C. A. and Moule, A. and Pines, A.} } @article {369, title = {Approach to high-resolution ex situ NMR spectroscopy}, journal = {Science}, volume = {293}, year = {2001}, note = {Science451BBTimes Cited:109Cited References Count:20}, month = {Jul 6}, pages = {82-85}, abstract = {

Nuclear magnetic resonance (NMR) experiments are typically performed with samples immersed in a magnet shimmed to high homogeneity. However, there are many circumstances in which it is impractical or undesirable to insert objects or subjects into the bore of a high-field magnet. Here we present a methodology based on an adaptation of nutation echoes that provides resolved spectra in the presence of matched inhomogeneous static and radiofrequency fields, thereby opening the way to high-resolution exsitu NMR, The observation of chemical shifts is regained through the use of multiple-pulse sequences of correlated, composite z-rotation pulses, producing resolved NMR spectra of liquid samples.

}, keywords = {echoes}, isbn = {0036-8075}, doi = {Doi 10.1126/Science.1061498}, url = {://WOS:000169780300032}, author = {Meriles, C. A. and Sakellariou, D. and Heise, H. and Moule, A. J. and Pines, A.} } @article {366, title = {Characterization of the effects of nonspecific xenon-protein interactions on Xe-129 chemical shifts in aqueous solution: Further development of xenon as a biomolecular probe}, journal = {Journal of Magnetic Resonance}, volume = {152}, year = {2001}, note = {J Magn Reson472QDTimes Cited:37Cited References Count:34}, month = {Sep}, pages = {79-86}, abstract = {

The sensitivity of Xe-129 chemical shifts to weak nonspecific xenon-protein interactions has suggested the use of xenon to probe biomolecular structure and interactions. The realization of this potential necessitates a further understanding of how different macromolecular properties influence the Xe-129 chemical shift in aqueous solution. Toward this goal, we have acquired Xe-129 NMR spectra of xenon dissolved in amino acid, peptide, and protein solutions under both native and denaturing conditions. In general, these cosolutes induce Xe-129 chemical shifts that are downfield relative to the shift in water, as they deshield the xenon nucleus through weak, diffusion-mediated interactions. Correlations between the extent of deshielding and molecular properties including chemical identity, structure, and charge are reported. Xenon deshielding was found to depend linearly on protein size under denaturing solution conditions; the denaturant itself has a characteristic effect on the Xe-129 chemical shift that likely results from a change in the xenon solvation shell structure. In native protein solutions, contributions to the overall Xe-129 chemical shift arise from the presence of weak xenon binding either in cavities or at the protein surface. Potential applications of xenon as a probe of biological systems including the detection of conformational changes and the possible quantification of buried surface area at protein-protein interfaces are discussed. (C) 2001 Academic Press.

}, keywords = {gas}, isbn = {1090-7807}, doi = {Doi 10.1006/Jmre.2001.2389}, url = {://WOS:000170995700009}, author = {Rubin, S. M. and Spence, M. M. and Pines, A. and Wemmer, D. E.} } @article {367, title = {Detection of a conformational change in maltose binding protein by Xe-129 NMR spectroscopy}, journal = {Journal of the American Chemical Society}, volume = {123}, year = {2001}, note = {J Am Chem Soc467XNTimes Cited:28Cited References Count:28}, month = {Sep 5}, pages = {8616-8617}, keywords = {blood}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja0110325}, url = {://WOS:000170729200029}, author = {Rubin, S. M. and Spence, M. M. and Dimitrov, I. E. and Ruiz, E. J. and Pines, A. and Wemmer, D. E.} } @article {373, title = {An experimental and theoretical investigation of the chemical shielding tensors of C-13(alpha) of alanine, valine, and leucine residues in solid peptides and in proteins in solution}, journal = {Journal of the American Chemical Society}, volume = {123}, year = {2001}, note = {J Am Chem Soc486FTTimes Cited:47Cited References Count:31}, month = {Oct 24}, pages = {10362-10369}, abstract = {

We have carried out a solid-state magic-angle sample-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopic investigation of the C-13(alpha), chemical shielding tensors of alanine, valine, and leucine residues in a series of crystalline peptides of known structure. For alanine and leucine, which are not branched at the beta -carbon, the experimental chemical shift anisotropy (CSA) spans (Omega) are large, about 30 ppm, independent of whether the residues adopt helical or sheet geometries, and are in generally good accord with Omega values calculated by using ab initio Hartree-Fock quantum chemical methods. The experimental Omegas for valine C-alpha in two peptides (in sheet geometries) are also large and in good agreement with theoretical predictions. In contrast, the \"CSAs\" (Delta sigma*) obtained from solution NMR data for alanine, valine, and leucine residues in proteins show major differences, with helical residues having Delta sigma* values of similar to6 ppm while sheet residues have Delta sigma* approximate to 27 ppm. The origins of these differences are shown to be due to the different definitions of the CSA, When defined in terms of the solution NMR CSA, the solid-state results also show small helical but large sheet CSA values. These results are of interest since they lead to the idea that only the beta -branched amino acids threonine, valine, and isoleucine can have small (static) tensor spans, Omega (in helical creometries), and that the small helical \"CSAs\" seen in solution NMR are overwhelmingly dominated by changes in tensor orientation, from sheet to helix. These results have important implications for solid-state NMR structural studies which utilize the CSA span, Omega, to differentiate between helical and sheet residues. Specifically, there will be only a small degree of spectral editing possible in solid proteins since the spans, Omega, for the dominant nonbranched amino acids are quite similar. Editing on the basis of Omega will, however, be very effective for many Thr, Val, and Hen residues, which frequently have small (similar to 15-20 ppm) helical CSA (Omega) spans.

}, keywords = {threonine}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja0115060}, url = {://WOS:000171808300025}, author = {Havlin, R. H. and Laws, D. D. and Bitter, H. M. L. and Sanders, L. K. and Sun, H. H. and Grimley, J. S. and Wemmer, D. E. and Pines, A. and Oldfield, E.} } @article {364, title = {Functionalized xenon as a biosensor}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {98}, year = {2001}, note = {P Natl Acad Sci USA472CZTimes Cited:112Cited References Count:29}, month = {Sep 11}, pages = {10654-10657}, abstract = {

The detection of biological molecules and their interactions is a significant component of modern biomedical research. In current biosensor technologies, simultaneous detection is limited to a small number of analytes by the spectral overlap of their signals. We have developed an NMR-based xenon biosensor that capitalizes on the enhanced signal-to-noise, spectral simplicity, and chemical-shift sensitivity of laser-polarized xenon to detect specific biomolecules at the level of tens of nanomoles. We present results using xenon \"functionalized\" by a biotin-modified supramolecular cage to detect biotin-avidin binding. This biosensor methodology can be extended to a multiplexing assay for multiple analytes.

}, keywords = {mri}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.191368398}, url = {://WOS:000170966800030}, author = {Spence, M. M. and Rubin, S. M. and Dimitrov, I. E. and Ruiz, E. J. and Wemmer, D. E. and Pines, A. and Yao, S. Q. and Tian, F. and Schultz, P. G.} } @article {365, title = {Resolution of Xe-129 chemical shifts at ultralow magnetic field}, journal = {Journal of the American Chemical Society}, volume = {123}, year = {2001}, note = {J Am Chem Soc463TWTimes Cited:9Cited References Count:39}, month = {Aug 22}, pages = {8133-8134}, keywords = {adsorption}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja011064s}, url = {://WOS:000170494200027}, author = {Saxena, S. and Wong-Foy, A. and Moule, A. J. and Seeley, J. A. and McDermott, R. and Clarke, J. and Pines, A.} } @article {375, title = {Evidence of nonspecific surface interactions between laser-polarized xenon and myoglobin in solution}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {97}, year = {2000}, note = {P Natl Acad Sci USA345XMTimes Cited:40Cited References Count:35}, month = {Aug 15}, pages = {9472-9475}, abstract = {

The high sensitivity of the magnetic resonance properties of xenon to its local chemical environment and the large Xe-129 NMR signals attainable through optical pumping have motivated the use of xenon as a probe of macromolecular structure and dynamics. In the present work, we report evidence for nonspecific interactions between xenon and the exterior of myoglobin in aqueous solution, in addition to a previously reported internal binding interaction. Xe-129 chemical shift measurements in denatured myoglobin solutions and under native conditions with varying xenon concentrations confirm the presence of nonspecific interactions. Titration data are modeled quantitatively with treatment of the nonspecific interactions as weak binding sites. Using laser-polarized xenon to measure Xe-129 spin-lattice relaxation times (T-1), we observed a shorter T-1 in the presence of 1 mM denatured apomyoglobin in 6 M deuterated urea (T-1 = 59 +/- 1 s) compared with that in 6 M deuterated urea alone (T-1 = 291 +/- 2 s), suggesting that nonspecific xenon-protein interactions can enhance Xe-129 relaxation. An even shorter T1 was measured in ? mM apomyoglobin in D2O (T-1 = 15 +/- 0.3 s), compared with that in D2O alone (T-1 = 506 +/- 5 s). This difference in relaxation efficiency likely results from couplings between laser-polarized xenon and protons in the binding cavity of apomyoglobin that may permit the transfer of polarization between these nuclei via the nuclear Overhauser effect.

}, keywords = {binding}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.170278897}, url = {://WOS:000088840500026}, author = {Rubin, S. M. and Spence, M. M. and Goodson, B. M. and Wemmer, D. E. and Pines, A.} } @article {376, title = {Exploring single-file diffusion in one-dimensional nanochannels by laser-polarized Xe-129 NMR spectroscopy (Cover Article)}, journal = {Journal of Physical Chemistry A}, volume = {104}, year = {2000}, note = {J Phys Chem A383EFTimes Cited:75Cited References Count:22}, month = {Dec 21}, pages = {11665-11670}, abstract = {

Single-file diffusion behavior is expected for atoms and molecules in one-dimensional gas phases of nanochannels with transverse dimensions that do not allow for the particles to bypass each other. Although single-file diffusion may play an important role in a wide range of industrial catalytic, geologic, and biological processes, experimental evidence is scarce despite the fact that the dynamics differ substantially from ordinary diffusion. We demonstrate the application of continuous-flow laser-polarized Xe-129 NMR spectroscopy for the study of gas transport into the effectively one-dimensional channels of a microporous material. The novel methodology makes it possible to monitor diffusion over a time scale of tens of seconds, often inaccessible by conventional NMR experiments. The technique can also be applied to systems with very small mobility factors or diffusion constants that are difficult to determine by currently available methods for diffusion measurement. Experiments using xenon in nanochannel systems can distinguish between unidirectional diffusion and single-file diffusion. The experimental observations indicate that single-file behavior for xenon in an organic nanochannel is persistent even at long diffusion times of over tens of seconds. Finally;using continuous flow laser-polarized Xe-129 NMR spectroscopy, we describe an intriguing correlation between the observed NMR line shape of xenon within the nanochannels and the gas transport into these channels.

}, keywords = {model}, isbn = {1089-5639}, doi = {Doi 10.1021/Jp002322v}, url = {://WOS:000165869600001}, author = {Meersmann, T. and Logan, J. W. and Simonutti, R. and Caldarelli, S. and Comotti, A. and Sozzani, P. and Kaiser, L. G. and Pines, A.} } @article {374, title = {A porous crystalline molecular solid explored by hyperpolarized xenon}, journal = {Angewandte Chemie-International Edition}, volume = {39}, year = {2000}, note = {Angew Chem Int Edit343KUTimes Cited:116Cited References Count:38}, pages = {2695-2698}, keywords = {c-13}, isbn = {1433-7851}, doi = {Doi 10.1002/1521-3773(20000804)39:15<2695::Aid-Anie2695>3.0.Co;2-M}, url = {://WOS:000088702200008}, author = {Sozzani, P. and Comotti, A. and Simonutti, R. and Meersmann, T. and Logan, J. W. and Pines, A.} } @proceedings {389, title = {Enhanced Surface NMR of Zeolites and Related Material Using Laser-Polarized Xenon}, journal = {Proc. 12th Int. Zeolite Conf.}, year = {1999}, pages = {2943-2950}, author = {Brunner, E. and Haake, M. and Pines, A. and Reimer, J. and Seydoux, R.} } @article {382, title = {High-T-c SQUIDs for low-field NMR and MRI of room temperature samples}, journal = {Ieee Transactions on Applied Superconductivity}, volume = {9}, year = {1999}, note = {Ieee T Appl SuperconPart 3225MCTimes Cited:5Cited References Count:18}, month = {Jun}, pages = {4424-4427}, abstract = {

We have constructed a high-T-c SQUID spectrometer to detect NMR signals from samples at room temperature in magnetic fields up to 3 mT. The multiloop SQUID magnetometer has a system noise of about 30 fT/Hz(1/2) at the relevant frequencies of 2 to 100 kHz, The magnetometer is operated in vacuum at 77 K, and is separated from the sample, which is less than 1.5 mm away, by a sapphire window, In a magnetic field of 2 mT we can detect the proton spin echo at 86 kHz without signal averaging. This sensitivity enables us to obtain one-dimensional images. In addition, we present data on hyperpolarized Xe-129, which has an optically pumped polarization of several percent.

}, keywords = {frequencies}, isbn = {1051-8223}, doi = {Doi 10.1109/77.784006}, url = {://WOS:000081964500386}, author = {Schlenga, K. and McDermott, R. F. and Clarke, J. and de Souza, R. E. and Wong-Foy, A. and Pines, A.} } @article {383, title = {Low-field magnetic resonance imaging with a high-T-c dc superconducting quantum interference device}, journal = {Applied Physics Letters}, volume = {75}, year = {1999}, note = {Appl Phys Lett259URTimes Cited:49Cited References Count:19}, month = {Dec 6}, pages = {3695-3697}, abstract = {

A spectrometer incorporating a high transition temperature dc superconducting quantum interference device (SQUID) is used to obtain nuclear magnetic resonance signals from protons in mineral oil at room temperature in fields up to 3 mT. The spatial separation between the SQUID magnetometer at 77 K and the sample at room temperature is less than 1 mm. At 2 mT, the signal is easily resolved in a single scan. Two-dimensional images of samples consisting of pieces of lucite or glass immersed in mineral oil are obtained at 2 mT. (C) 1999 American Institute of Physics. [S0003-6951(99)03649-9].

}, keywords = {mri}, isbn = {0003-6951}, doi = {Doi 10.1063/1.125432}, url = {://WOS:000083912800035}, author = {Schlenga, K. and McDermott, R. and Clarke, J. and de Souza, R. E. and Wong-Foy, A. and Pines, A.} } @article {387, title = {NMR and MRI obtained with high transition temperature DC SQUIDs}, journal = {Journal of the Brazilian Chemical Society}, volume = {10}, year = {1999}, note = {J Brazil Chem Soc259BETimes Cited:11Cited References Count:30}, month = {Jul-Aug}, pages = {307-312}, abstract = {

We have measured nuclear magnetic resonance (NMR) signals from several samples at room temperature in magnetic fields ranging from about 0.05 mT to 2 mT using a spectrometer based on a high-T-c de SQUID (high transition temperature de Superconducting QUantum Interference Device). We are able to observe proton signals from 1 mL of mineral oil in 2 mT in a single transient. The sensitivity of this system has also allowed the detection of proton NMR at magnetic fields as low as 0.059 mT, which is comparable to the Earth\&$\#$39;s field. Such results make possible a number of new experiments in magnetic resonance imaging (MRI). We present a two-dimensional image of a phantom filled with mineral oil obtained in a field of 2 mT.

}, keywords = {system}, isbn = {0103-5053}, url = {://WOS:000083873500009}, author = {de Souza, R. E. and Schlenga, K. and Wong-Foy, A. and McDermott, R. and Pines, A. and Clarke, J.} } @article {380, title = {NMR and MRI using laser-polarized xenon}, journal = {Spectroscopy}, volume = {14}, year = {1999}, note = {Spectroscopy216AZTimes Cited:19Cited References Count:65}, month = {Jul}, pages = {26-33}, abstract = {

The application of optical pumping methods increases the nuclear spin polarization of noble gases by four to five orders of magnitude. This enormous increase in polarization translates directly into greatly enhanced signals for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Selected experiments devised to exploit this enhanced sensitivity are reviewed, including xenon NMR/MRI studies of biological systems and polarization transfer to molecules in solution and on surfaces.

}, keywords = {liquid xenon}, isbn = {0887-6703}, url = {://WOS:000081419500003}, author = {Song, Y. Q. and Goodson, B. M. and Pines, A.} } @article {381, title = {NMR with a continuously circulating flow of laser-polarized Xe-129}, journal = {Journal of Physical Chemistry B}, volume = {103}, year = {1999}, note = {J Phys Chem B203HNTimes Cited:45Cited References Count:35}, month = {Jun 3}, pages = {4629-4637}, abstract = {

In this paper we describe the construction of an apparatus for optical pumping of Xe-129 in a circulating gas system connected to a probe for static high-field NMR. The optimal working conditions for the optical pumping under flow are explored, yielding a continuous gas now with a steady-state spin-polarization of about 2\%. It is shown that on various types of high surface area materials a steady-state of adsorbed laser-polarized xenon can be;reached with polarizations of about 0.3\%. NMR spectroscopy of this layer is greatly facilitated due to the renewable magnetization under the continuous-flow conditions allowing unprecedented fast detection of two-dimensional NMR experiments with laser-polarized Xe. The steady-state spin-polarization of adsorbed Xe-129 gives rise to cross-relaxation to surface nuclei such as H-1 and Si-29. A direct spin-polarization-induced nuclear Overhauser effect (SPINOE) to heteronuclei is observed with an enhancement factor of about 20-30. A method is presented for simple modulation of the spin-polarization direction in the fringe field of the high-field magnet; this is exploited to obtain difference SPINOE spectra to highlight only the surface nuclei. Furthermore, a transfer via cross-polarization (CP) from adsorbed Xe to surface protons is demonstrated to select surface groups with reduced mobility compared to SPINOE detection.

}, keywords = {zeolites}, isbn = {1089-5647}, doi = {Doi 10.1021/Jp9821984}, url = {://WOS:000080702600011}, author = {Seydoux, R. and Pines, A. and Haake, M. and Reimer, J. A.} } @article {384, title = {Study of xenon binding in cryptophane-A using laser-induced NMR polarization enhancement}, journal = {Journal of the American Chemical Society}, volume = {121}, year = {1999}, note = {J Am Chem Soc189BTTimes Cited:73Cited References Count:64}, month = {Apr 14}, pages = {3502-3512}, abstract = {

In solution, spin-polarization transfer between laser-polarized xenon and the hydrogen nuclei of nearby molecules leads to signal enhancements in the resolved H-1 NMR spectrum, offering new opportunities for probing the chemical environment of xenon atoms. Following binding of laser-polarized xenon to molecules of cryptophane-A, selective enhancements of the H-1 NMR signals were observed. A theoretical framework for the interpretation of such experimental results is provided, and the spin polarization-induced nuclear Overhauser effects are shown to yield information about the molecular environment of xenon. The observed selective H-1 enhancements allowed xenon-proton internuclear distances to be estimated. These distances reveal structural characteristics of the complex, including the preferred molecular conformations adopted by cryptophane-A upon binding of xenon.

}, keywords = {SPECTROSCOPY}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja9841916}, url = {://WOS:000079884800033}, author = {Luhmer, M. and Goodson, B. M. and Song, Y. Q. and Laws, D. D. and Kaiser, L. and Cyrier, M. C. and Pines, A.} } @article {393, title = {Effects of diffusion on magnetic resonance imaging of laser-polarized xenon gas}, journal = {Journal of Chemical Physics}, volume = {108}, year = {1998}, note = {J Chem PhysZh114Times Cited:30Cited References Count:24}, month = {Apr 15}, pages = {6233-6239}, abstract = {

Molecular diffusion during the application of magnetic field gradients can distort magnetic resonance images. A systematic characterization of these distortions in one dimension was performed using highly spin-polarized xenon gas. By varying the strength of the applied gradient and the geometric dimension of the sample, the evolution of these image distortions between the regimes of strong and weak diffusion was observed. These results are compared with numerical simulations. By directly measuring the displacement distribution of the polarized xenon atoms, it is shown that in the weak-diffusion regime the image distortions originate from the restricted diffusive motion near the sample boundaries, in agreement with previous theoretical work. Additionally, it is shown that the effects of diffusion can be utilized to enhance the contrast between the boundaries and bulk in the images of polarized gas samples, and thus may be exploited as a means of boundary detection in such systems. (C) 1998 American Institute of Physics. [S0021-9606(98)02915-8].

}, keywords = {xe-129}, isbn = {0021-9606}, doi = {Doi 10.1063/1.476030}, url = {://WOS:000073073700018}, author = {Song, Y. Q. and Goodson, B. M. and Sheridan, B. and de Swiet, T. M. and Pines, A.} } @article {404, title = {Enhancement of C-13 NMR signals in solid C-60 and C-70 using laser-polarized xenon}, journal = {Chemical Physics Letters}, volume = {290}, year = {1998}, note = {Chem Phys LettZw963Times Cited:30Cited References Count:31}, month = {Jun 26}, pages = {112-116}, abstract = {

NMR signals emanating from surface nuclei of solids may be enhanced by the transfer of spin polarization from laser-polarized noble gases via SPINOE (spin polarization induced nuclear Overhauser effect). The present contribution describes experiments in which the spin polarization is transferred under magic angle spinning (MAS) from laser-polarized Xe-129 to C-13, a nuclear spin with a low gyromagnetic ratio in the fullerenes C-60 and C-70, polycrystalline materials with a low surface area. In C-70, differential enhancement of the NMR is observed for the different atomic sites in the molecule. (C) 1998 Elsevier Science B.V. All rights reserved.

}, keywords = {c60}, isbn = {0009-2614}, doi = {Doi 10.1016/S0009-2614(98)00473-4}, url = {://WOS:000074466600018}, author = {Brunner, E. and Haake, M. and Pines, A. and Reimer, J. A. and Seydoux, R.} } @article {402, title = {A high-resolution(17)O NMR study of siliceous zeolite faujasite}, journal = {Journal of the American Chemical Society}, volume = {120}, year = {1998}, note = {J Am Chem SocZj097Times Cited:66Cited References Count:19}, month = {Apr 15}, pages = {3510-3511}, keywords = {workstation computers}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja9743001}, url = {://WOS:000073179200032}, author = {Bull, L. M. and Cheetham, A. K. and Anupold, T. and Reinhold, A. and Samoson, A. and Sauer, J. and Bussemer, B. and Lee, Y. and Gann, S. and Shore, J. and Pines, A. and Dupree, R.} } @article {392, title = {Imaging of laser-polarized solid xenon}, journal = {Solid State Nuclear Magnetic Resonance}, volume = {10}, year = {1998}, note = {Solid State Nucl MagZh559Times Cited:5Cited References Count:16}, month = {Feb}, pages = {247-250}, abstract = {

The enhanced spin polarization produced by optical pumping of gaseous rubidium/xenon samples has made possible a number of recent experiments in nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI). Here we report MRI of laser-polarized xenon in the solid phase at low temperature. Due to the high xenon density in the solid phase and the enhanced spin polarization, it is possible to achieve high intensity and spatial resolution of the image. Signals were observed from xenon films solidified onto the glass container walls and not from an enclosed chili pepper. (C) 1998 Elsevier Science B.V.

}, keywords = {gas}, isbn = {0926-2040}, doi = {Doi 10.1016/S0926-2040(97)00078-7}, url = {://WOS:000073123500009}, author = {Song, Y. Q. and Taylor, R. E. and Pines, A.} } @article {403, title = {Surface NMR using laser-polarized (129)Xe under magic angle spinning conditions}, journal = {Journal of Magnetic Resonance}, volume = {130}, year = {1998}, note = {J Magn ResonZc833Times Cited:46Cited References Count:21}, month = {Jan}, pages = {145-148}, abstract = {

NMR signals of surface nuclei of solids may be enhanced by the transfer of spin polarization from laser-polarized noble gases. Until now such experiments have not been feasible under conditions of magic angle spinning. In the present contribution it is shown that laser-polarized (129)Xe can be inserted into a spinning rotor under continuous-flow conditions using helium as a carrier gas. Effective adsorption of xenon on the sample occurs at temperatures of about 163-173 K making possible the observation of a spin polarization induced nuclear Overhauser effect (SPINOE) from the laser-polarized (129)Xe to surface (1)H nuclei of SiO(2) (AEROSIL300). This technique opens the way to selectively enhanced high-resolution multinuclear surface NMR experiments. (C) 1998 Academic Press.

}, keywords = {flow}, isbn = {1090-7807}, doi = {Doi 10.1006/Jmre.1997.1296}, url = {://WOS:000072622700022}, author = {Brunner, E. and Seydoux, R. and Haake, M. and Pines, A. and Reimer, J. A.} } @article {395, title = {Surface selective H-1/Si-29 CP NMR by NOE enhancement from laser polarized xenon}, journal = {Journal of Magnetic Resonance}, volume = {133}, year = {1998}, note = {J Magn Reson116WNTimes Cited:27Cited References Count:20}, month = {Aug}, pages = {299-303}, abstract = {

The surface proton spin polarization created by the spin-polarization-induced nuclear Overhauser effect from optically polarized xenon can be transferred in a subsequent step by solid-state cross polarization to another nuclear spin species such as Si-29. The technique exploits the dipolar interactions of xenon nuclear spins with high gamma nuclei such as H-1, and is experimentally simpler than direct polarization transfer from Xe-129 to heteronuclei such as C-13 and Si-29. (C) 1998 Academic Press.

}, keywords = {spins}, isbn = {1090-7807}, doi = {Doi 10.1006/Jmre.1998.1447}, url = {://WOS:000075748200008}, author = {Pietrass, T. and Seydoux, R. and Pines, A.} } @article {421, title = {Cross-polarization from quadrupolar nuclei to silicon using low-radio-frequency amplitudes during magic-angle spinning}, journal = {Journal of Physical Chemistry B}, volume = {101}, year = {1997}, note = {J Phys Chem BWu630Times Cited:51Cited References Count:50}, month = {Apr 17}, pages = {3240-3249}, abstract = {

The dynamics of cross-polarization from the central transition of a quadrupolar nucleus (Al-27 or Na-23) to a spin-1/2 nucleus (Si-29) during magic-angle spinning and using low-radio-frequency Geld strengths are analyzed for the mineral low albite. Under these conditions additional complications in the spin-lock behavior of the quadrupolar nucleus and in the cross-polarization process were found experimentally and are examined in detail. A step-by-step procedure for optimizing cross-polarization from the central transition of a quadrupolar nucleus to a spin-1/2 nucleus is described. Significant enhancement of Si-29 NMR sensitivity and several applications are demonstrated.

}, keywords = {locking}, isbn = {1089-5647}, doi = {Doi 10.1021/Jp9623711}, url = {://WOS:A1997WU63000031}, author = {DePaul, S. M. and Ernst, M. and Shore, J. S. and Stebbins, J. F. and Pines, A.} } @article {411, title = {Enhancement of surface NMR by laser-polarized noble gases}, journal = {Physical Review B}, volume = {55}, year = {1997}, note = {Phys Rev BWy504Times Cited:65Cited References Count:34}, month = {May 1}, pages = {11604-11610}, abstract = {

The transfer of spin polarization from laser-polarized helium and xenon to spins such as H-1 and C-13 On the surface of high-surface-area solids (Aerosil) is demonstrated over a temperature range from 4 to 200 K. The transfer mechanism is dipole-dipole cross relaxation between the spins of the adsorbed mobile noble gas and the surface spins (spin-polarization-induced nuclear Overhauser effect). The enhancement of surface proton magnetization by laser-polarized helium at 4 K and 10 K is between one and twofold. Using laser-polarized xenon, enhancement factors of up to 20 were obtained when compared to the Boltzmann polarization in a field of 4.2 T and at a temperature of 130 K.

}, keywords = {he-3}, isbn = {0163-1829}, doi = {Doi 10.1103/Physrevb.55.11604}, url = {://WOS:A1997WY50400096}, author = {Room, T. and Appelt, S. and Seydoux, R. and Hahn, E. L. and Pines, A.} } @article {420, title = {In vivo NMR and MRI using injection delivery of laser-polarized xenon}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {94}, year = {1997}, note = {P Natl Acad Sci USAYn574Times Cited:55Cited References Count:39}, month = {Dec 23}, pages = {14725-14729}, abstract = {

Because xenon NMR is highly sensitive to the local environment, laser-polarized xenon could be a unique probe of living tissues. Realization of clinical and medical science applications beyond lung airspace imaging requires methods of efficient delivery of laser-polarized xenon to tissues, because of the short spin-lattice relaxation times and relatively low concentrations of xenon attainable in the body. Preliminary results from the application of a polarized xenon injection technique for in vivo Xe-129 NMR/MRI are extrapolated along with a simple model of xenon transit to show that the peak local concentration of polarized xenon delivered to tissues by injection may exceed that delivered by respiration by severalfold.

}, keywords = {humans}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.94.26.14725}, url = {://WOS:000071182800090}, author = {Goodson, B. M. and Song, Y. Q. and Taylor, R. E. and Schepkin, V. D. and Brennan, K. M. and Chingas, G. C. and Budinger, T. F. and Navon, G. and Pines, A.} } @article {406, title = {Multiple-quantum magic-angle spinning and dynamic-angle spinning NMR spectroscopy of quadrupolar nuclei}, journal = {Solid State Nuclear Magnetic Resonance}, volume = {8}, year = {1997}, note = {Solid State Nucl MagWy629Times Cited:60Cited References Count:40}, month = {Mar}, pages = {1-16}, abstract = {

Several aspects of the Multiple-Quantum Magic-Angle Spinning (MQMAS) technique (L, Frydman and J,S, Harwood, J, Am, Chem, Sec., 117 (1995) 5367) are compared with Dynamic-Angle Spinning (DAS), Examples of MQMAS spectra are shown for I = 3/2 nuclei with C-Q up to 3.6 MHz, and for: Al-27 (I = 5/2) with C-Q up to 10 MHz. The MQMAS linewidth is largely independent of the magnitude of the homonuclear dipolar interaction, while the spinning sideband manifold is similar to that observed in DAS experiments, MQMAS is technically simple and routinely useful for studying nuclei with short spin-lattice relaxation times, but care must be taken in its use for quantitative studies as the excitation of the triple-quantum coherence is not uniform, In this regard, MQMAS is most useful for samples with small quadrupolar coupling constants, In the specific case of O-17, DAS would give spectra with excellent resolution in comparison to MQMAS, The different advantages of DAS and MQMAS make them useful complementary techniques in many cases,Two additional methods are also presented for extracting the chemical shift anisotropy (CSA) directly for quadrupolar nuclei using the multiple-quantum scheme, (C) 1997 Elsevier Science B,V.

}, keywords = {rb-87}, isbn = {0926-2040}, doi = {Doi 10.1016/S0926-2040(96)01277-5}, url = {://WOS:A1997WY62900001}, author = {Wang, S. H. and Xu, Z. and Baltisberger, J. H. and Bull, L. M. and Stebbins, J. F. and Pines, A.} } @article {410, title = {Optical magnetic resonance imaging of Rb vapor in low magnetic fields}, journal = {Physics Letters A}, volume = {226}, year = {1997}, note = {Phys Lett AWf939Times Cited:12Cited References Count:19}, month = {Feb 10}, pages = {69-74}, abstract = {

By applying magnetic field gradients to alkali vapor cells, images of the spatial distribution of spin-polarized Rb atoms were obtained. Optical pumping is used to produce precessing spin-polarization in the ground state. Detection of the coherent spin transients is performed in the time-domain by a single optical probe beam covering the whole sample cell. Spatial resolution of better than 1 mm has been achieved by a projection-reconstruction method.

}, keywords = {xe-129}, isbn = {0375-9601}, doi = {Doi 10.1016/S0375-9601(96)00927-9}, url = {://WOS:A1997WF93900012}, author = {Skalla, J. and Wackerle, G. and Mehring, M. and Pines, A.} } @article {413, title = {P-31 to Se-77 cross polarization in beta-P4Se3}, journal = {Solid State Nuclear Magnetic Resonance}, volume = {8}, year = {1997}, note = {Solid State Nucl MagYd904Times Cited:7Cited References Count:12}, month = {Aug}, pages = {265-267}, abstract = {

Cross polarization from P-31 to Se-77 is demonstrated in beta-P4Se3. This material, an inorganic glass, is readily synthesized from the elements and serves as a convenient sample for setting the Hartmann-Hahn condition. (C) 1997 Elsevier Science B.V.

}, keywords = {f-19}, isbn = {0926-2040}, doi = {Doi 10.1016/S0926-2040(97)00012-X}, url = {://WOS:A1997YD90400008}, author = {Pietrass, T. and Seydoux, R. and Roth, R. E. and Eckert, H. and Pines, A.} } @article {409, title = {Selective enhancement of NMR signals for alpha-cyclodextrin with laser-polarized xenon}, journal = {Angewandte Chemie-International Edition in English}, volume = {36}, year = {1997}, note = {Angew Chem Int EditYh944Times Cited:48Cited References Count:29}, month = {Nov 14}, pages = {2368-2370}, keywords = {solids}, isbn = {0570-0833}, doi = {Doi 10.1002/Anie.199723681}, url = {://WOS:A1997YH94400025}, author = {Song, Y. Q. and Goodson, B. M. and Taylor, R. E. and Laws, D. D. and Navon, G. and Pines, A.} } @article {407, title = {SQUID detected NMR of laser-polarized xenon at 4.2 K and at frequencies down to 200 Hz}, journal = {Chemical Physics Letters}, volume = {272}, year = {1997}, note = {Chem Phys LettXh440Times Cited:18Cited References Count:32}, month = {Jun 27}, pages = {245-249}, abstract = {

A spectrometer based on a dc SQUID (superconducting quantum interference device) was used to record nuclear magnetic resonance signals from laser-polarized Xe-129 at 4.2 K and at frequencies ranging from about 200 Hz to 110 kHz in magnetic fields varying from about 0.02 to 9 mT. The Xe-129 resonance linewidths were found to increase with increasing magnetic field, and, at a given field, to increase with higher Xe-129 concentration. The spin-lattice relaxation times were observed to decrease from similar to 8000 s at 5 mT to similar to 2000 s at fields below 0.05 mT. Such long relaxation times make possible a variety of spin polarization transfer experiments. (C) 1997 Published by Elsevier Science B.V.

}, keywords = {relaxation}, isbn = {0009-2614}, doi = {Doi 10.1016/S0009-2614(97)88016-5}, url = {://WOS:A1997XH44000017}, author = {TonThat, D. M. and Ziegeweid, M. and Song, Y. Q. and Munson, E. J. and Appelt, S. and Pines, A. and Clarke, J.} } @article {419, title = {Surface-enhanced NMR using continuous-flow laser-polarized xenon}, journal = {Journal of the American Chemical Society}, volume = {119}, year = {1997}, note = {J Am Chem SocYk502Times Cited:66Cited References Count:16}, month = {Dec 3}, pages = {11711-11712}, keywords = {solids}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja9713587}, url = {://WOS:A1997YK50200029}, author = {Haake, M. and Pines, A. and Reimer, J. A. and Seydoux, R.} } @article {422, title = {Determination of quadrupolar and chemical shielding tensors using solid-state two-dimensional NMR spectroscopy}, journal = {Journal of Chemical Physics}, volume = {105}, year = {1996}, note = {J Chem PhysVv625Times Cited:18Cited References Count:40}, month = {Dec 1}, pages = {9412-9420}, abstract = {

The quadrupolar and chemical shift tensors, as well as the relative orientation of the two principle axis systems, are accurately determined using a two-dimensional nuclear magnetic resonance technique. Good agreement between experimental and simulated two-dimensional spectra is obtained for a series of rubidium and sodium compounds at multiple magnetic field strengths. Extension of this technique to correlate the quadrupolar and dipolar interactions, as well as the incorporation of a purely isotropic dimension resulting in a three-dimensional experiment is also discussed. (C) 1996 American Institute of Physics.

}, keywords = {line-shapes}, isbn = {0021-9606}, doi = {Doi 10.1063/1.472776}, url = {://WOS:A1996VV62500003}, author = {Shore, J. S. and Wang, S. H. and Taylor, R. E. and Bell, A. T. and Pines, A.} } @article {426, title = {Enhancement of solution NMR and MRI with laser-polarized xenon}, journal = {Science}, volume = {271}, year = {1996}, note = {ScienceUc778Times Cited:230Cited References Count:41}, month = {Mar 29}, pages = {1848-1851}, abstract = {

Optical pumping with laser light can be used to polarize the nuclear spins of gaseous xenon-129. When hyperpolarized xenon-129 is dissolved in liquids, a time-dependent departure of the proton spin polarization from its thermal equilibrium is observed, The variation of the magnetization is an unexpected manifestation of the nuclear Overhauser effect, a consequence of cross-relaxation between the spins of solution protons and dissolved xenon-129. Time-resolved magnetic resonance images of both nuclei in solution show that the proton magnetization is selectively perturbed in regions containing spin-polarized xenon-129. This effect could find use in nuclear magnetic resonance spectroscopy of surfaces and proteins and in magnetic resonance imaging.

}, keywords = {resonance}, isbn = {0036-8075}, doi = {Doi 10.1126/Science.271.5257.1848}, url = {://WOS:A1996UC77800041}, author = {Navon, G. and Song, Y. Q. and Room, T. and Appelt, S. and Taylor, R. E. and Pines, A.} } @article {430, title = {Isotropic second-order dipolar shifts in the rotating frame}, journal = {Journal of Chemical Physics}, volume = {104}, year = {1996}, note = {J Chem PhysUm909Times Cited:9Cited References Count:44}, month = {Jun 1}, pages = {8258-8268}, abstract = {

An experiment is described that utilizes the truncation of the Hamiltonian in the rotating frame by a radio-frequency field designed to yield an isotropic shift for the dipolar coupling. This approach allows the measurement of a normally orientation-dependent coupling constant by a single isotropic value. The dipolar isotropic shift is closely related to the field-dependent chemical shift in solids due to the second-order dipolar perturbation observed in magic-angle spinning experiments. In the rotating frame, larger shifts of up to 1000 Hz can be observed for the case of a one-bond C-H coupling compared to a shift of a few Hertz in the laboratory-frame experiment. In addition to the isotropic shift, a line broadening due to the P-4(cos beta) terms is observed when the experiment is carried out under magic-angle sample spinning (MAS) conditions, leading to the requirement of higher-order averaging such as double rotation (DOR) for obtaining narrow lines. As an application of this new experiment the separation of CH, CH2, and CH3 groups in a 2D spectrum under MAS is demonstrated. Implemented under DOR it could be used as a technique to select carbon atoms according to the number of directly attached protons. (C) 1996 American Institute of Physics.

}, keywords = {spins}, isbn = {0021-9606}, doi = {Doi 10.1063/1.471579}, url = {://WOS:A1996UM90900008}, author = {Ernst, M. and Kolbert, A. C. and Schmidt-Rohr, K. and Pines, A.} } @article {433, title = {NMR of laser-polarized xenon in human blood}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {93}, year = {1996}, note = {P Natl Acad Sci USAVt054Times Cited:92Cited References Count:27}, month = {Nov 12}, pages = {12932-12936}, abstract = {

By means of optical pumping with laser light it is possible to enhance the nuclear spin polarization of gaseous xenon by four to five orders of magnitude, The enhanced polarization has allowed advances in nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI), including polarization transfer to molecules and imaging of lungs and other void spaces, A critical issue for such applications is the delivery of xenon to the sample while maintaining the polarization, Described herein is an efficient method for the introduction of laser-polarized xenon into systems of biological and medical interest for the purpose of obtaining highly enhanced NMR/MRI signals. Using this method, we have made the first observation of the time-resolved process of xenon penetrating the red blood cells in fresh human blood-the xenon residence time constant in the red blood cells was measured to be 20.4+/-2 ms. The potential of certain biologically compatible solvents for delivery of laser-polarized xenon to tissues for NMR/MRI is discussed in light of their respective relaxation and partitioning properties.

}, keywords = {gas}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.93.23.12932}, url = {://WOS:A1996VT05400048}, author = {Bifone, A. and Song, Y. Q. and Seydoux, R. and Taylor, R. E. and Goodson, B. M. and Pietrass, T. and Budinger, T. F. and Navon, G. and Pines, A.} } @article {434, title = {Rotational diffusion measurements of suspended colloidal particles using two-dimensional exchange nuclear magnetic resonance}, journal = {Journal of Chemical Physics}, volume = {104}, year = {1996}, note = {J Chem PhysTn837Times Cited:13Cited References Count:24}, month = {Jan 8}, pages = {509-520}, abstract = {

We present here an experimental and theoretical study of the application of two-dimensional exchange nuclear magnetic resonance spectroscopy (NMR) to the investigation of the rotational diffusion of colloidal particles. The theoretical discussion includes the nature of the NMR frequency time-correlation function where the NMR interaction is represented by the chemical shift anisotropy (CSA). Time-correlation functions for the isotropic rotational diffusion of a suspension of colloidal particles containing single and multiple sites are derived in addition to time-correlation functions for the rotational diffusion of a suspension of symmetric top particles containing an isotropic distribution of a single CSA interaction. Simulations of two-dimensional exchange spectra for particles undergoing isotropic rotational diffusion are presented. We performed two-dimensional exchange NMR experiments on a colloidal suspension of spherical poly(methyl methacrylate) (PMMA) particles which were synthesized with a 20\% enrichment in C-13 at the carbonyl site. Rotational diffusion time-correlation functions determined from the experimental exchange spectra are consistent with the composition of the colloidal suspension. Detailed explanations of the syntheses of the enriched methyl C-13-(carbonyl)-methacrylate monomer and the small quantities of 20\% enriched C-13-(carbonyl)-poly(methyl methacrylate) microspheres used for this study are presented. (C) 1996 American Institute of Physics.

}, keywords = {scattering}, isbn = {0021-9606}, doi = {Doi 10.1063/1.470847}, url = {://WOS:A1996TN83700009}, author = {Barrall, G. A. and Schmidt-Rohr, K. and Lee, Y. K. and Landfester, K. and Zimmermann, H. and Chingas, G. C. and Pines, A.} } @article {435, title = {Triple-quantum two-dimensional Al-27 magic-angle spinning nuclear magnetic resonance spectroscopic study of aluminosilicate and aluminate crystals and glasses}, journal = {Journal of the American Chemical Society}, volume = {118}, year = {1996}, note = {J Am Chem SocVa026Times Cited:139Cited References Count:31}, month = {Jul 31}, pages = {7209-7214}, abstract = {

A new two-dimensional magic-angle spinning NMR experiment(1,2) using multiple-quantum coherences of half-integer quadrupolar nuclei was used to study Al-27 sites in crystalline samples of leucite (KAlSi2O6), anorthite (CaAl2Si2O8), and kyanite (Al2SiO5), as well as CaAl2Si2O8 glass and a magnesium aluminoborate glass. In the crystals, multiple sites are partially resolved and new results for isotropic chemical shifts and quadrupolar parameters are derived, using data collected at a single magnetic field. Data for both leucite and anorthite are consistent with previous results that correlate chemical shifts with mean intertetrahedral bond angle. Signal can be obtained from sites with quadrupolar coupling constants as large as 9 MHz, but intensities are reduced. In the aluminoborate glass, peaks for sites with different Al coordination numbers are well separated. The lack of such features in CaAl2Si2O8 glass rules out the presence of significant quantities of AlO5 and AlO6 groups.

}, keywords = {anorthite}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja9606586}, url = {://WOS:A1996VA02600027}, author = {Baltisberger, J. H. and Xu, Z. and Stebbins, J. F. and Wang, S. H. and Pines, A.} } @article {453, title = {High-Field Cross-Polarization Nmr from Laser-Polarized Xenon to Surface Nuclei}, journal = {Applied Magnetic Resonance}, volume = {8}, year = {1995}, note = {Appl Magn ResonRt202Times Cited:30Cited References Count:17}, pages = {373-384}, abstract = {

A method for NMR investigations of surface nuclei using cross polarization from optically polarized xenon (OPCP) is described. We find this methodology results in enhancement factors of approximately 10(3) upon application to surface protons. The dynamics of Xe-129 transfer to protons is examined in some detail, including the time, temperature, and multiple contact dependences of signal intensities. Furthermore, we discuss the sensitivity of the transfer process to spatial diffusion. Finally, we report on application of the OPCP experiment to a low total surface area sample.

}, keywords = {gel}, isbn = {0937-9347}, url = {://WOS:A1995RT20200005}, author = {Gaede, H. C. and Song, Y. Q. and Taylor, R. E. and Munson, E. J. and Reimer, J. A. and Pines, A.} } @article {444, title = {Low-Power Decoupling Sequences for High-Resolution Chemical-Shift and Local-Field Nmr-Spectra of Liquid-Crystals}, journal = {Journal of Magnetic Resonance Series A}, volume = {113}, year = {1995}, note = {J Magn Reson Ser AQw158Times Cited:11Cited References Count:29}, month = {Apr}, pages = {169-176}, abstract = {

Various new and well-established multiple-pulse sequences that provide homonuclear dipolar decoupling are compared on a high-resolution spectrometer/probe configuration using low RF-irradiation powers. Proton-proton decoupled carbon-13 spectra of singly C-13-labeled benzene dissolved in a nematic liquid crystal and of the liquid crystal 152 are presented. Two classes of multiple-pulse sequences are studied that produce either broadband decoupled carbon spectra or separated local-held spectra. Several new approaches for the design of windowless sequences are demonstrated to be valuable in these heteronuclear experiments. They include implementations of the iterative MLEV scheme and the use of 270 degrees pulses. Furthermore, noncyclic propagators have been found that exhibit advantages over closely related cyclic analogues in both classes of decoupling sequences. (C) 1995 Academic Press, Inc.

}, keywords = {dipolar}, isbn = {1064-1858}, doi = {Doi 10.1006/Jmra.1995.1077}, url = {://WOS:A1995QW15800005}, author = {Nanz, D. and Ernst, M. and Hong, M. and Ziegeweid, M. A. and Schmidt-Rohr, K. and Pines, A.} } @article {441, title = {Magnetic-Resonance Evidence for Metallic State in Highly Conducting Polyaniline}, journal = {Synthetic Metals}, volume = {69}, year = {1995}, note = {Synthetic MetQl601Times Cited:9Cited References Count:12}, month = {Mar 1}, pages = {243-244}, abstract = {

Polyaniline doped with camphor sulfonic acid (PANI-CSA) has been shown to yield a material which, after processing from solutions in meta-cresol, exhibit a temperature independent magnetic susceptibility down to 50K. Below 50K a Curie like contribution sets in. We also report C-13 NMR experiments which clearly show that the C-13 spin lattice relaxation rates obey the Korringa relation for relaxation via the hyperfine coupling to conduction electrons.

}, keywords = {polymers}, isbn = {0379-6779}, doi = {Doi 10.1016/0379-6779(94)02435-2}, url = {://WOS:A1995QL60100097}, author = {Sariciftci, N. S. and Kolbert, A. C. and Cao, Y. and Heeger, A. J. and Pines, A.} } @article {451, title = {Nmr Measurement of Signs and Magnitudes of C-H Dipolar Couplings in Lecithin}, journal = {Journal of the American Chemical Society}, volume = {117}, year = {1995}, note = {J Am Chem SocQn458Times Cited:45Cited References Count:25}, month = {Mar 22}, pages = {3310-3311}, keywords = {orientation}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja00116a051}, url = {://WOS:A1995QN45800051}, author = {Hong, M. and Schmidt-Rohr, K. and Pines, A.} } @article {440, title = {Orientation and Motion of Tetrahydrofuran in Graphite-Intercalation Compounds - Proton Nmr-Studies of Cs(Thf)(1.3)C-24 and K(Thf)(2.5)C-24}, journal = {Journal of Physical Chemistry}, volume = {99}, year = {1995}, note = {J Phys Chem-UsRg562Times Cited:5Cited References Count:31}, month = {Jun 29}, pages = {10565-10572}, abstract = {

The orientation and motion of tetrahydrofuran (THF) in the ternary graphite intercalation compounds Cs-(THF)(1.3)C-24 and K(THF)(2.5)C-24 have been studied by proton NMR. Simulations of the NMR spectra indicate that the THF molecules in CS(THF)(1.3)C-24 have their mean planes oriented parallel to the layers of the host lattice, while the THF molecules in K(THF)(2.5)C-24 have their mean planes oriented at an angle between 50 degrees and 75 degrees from the graphite layers. The proton NMR spectra of both compounds show evidence that the THF molecules rotate about the normal to the graphite layers and confirm X-ray diffraction studies showing a degree of orientational disorder in the samples, corresponding to a mosaic spread in the graphite layer orientation. The conformation of the intercalated THF was studied by simulating the experimental NMR spectra using models for the conformational motion of THF. Simulations indicate that the conformation of intercalated THF is different than gas or liquid phase THF, which has been found to have a ring puckering amplitude of 0.38-0.44 Angstrom and to undergo nearly free pseudorotation through a series of conformations. Best agreement between simulated and experimental NMR spectra of Cs(THF)(1.3)C-24 was Obtained with THF interconverting between two conformations of C-s symmetry and a puckering amplitude of 0.30 Angstrom. Free or slightly hindered pseudorotation of THF (observed in liquid or gaseous THF) in this compound produces simulated spectra that differ significantly from the experimental spectra. Simulated proton NMR spectra of K(THF)(2.5)C-24 using conformations of C-s symmetry or free or slightly hindered pseudorotation of THF do not fit the experimental spectra sufficiently well to allow distinction between the conformational motions or to exclude other possible motions.

}, keywords = {system}, isbn = {0022-3654}, doi = {Doi 10.1021/J100026a020}, url = {://WOS:A1995RG56200020}, author = {Schmidt, C. and Rosen, M. E. and Caplan, D. F. and Pines, A. and Quinton, M. F.} } @article {452, title = {Solid-State O-17 Magic-Angle and Dynamic-Angle Spinning Nmr-Study of the Sio2 Polymorph Coesite}, journal = {Journal of Physical Chemistry}, volume = {99}, year = {1995}, note = {J Phys Chem-UsRn706Times Cited:95Cited References Count:41}, month = {Aug 10}, pages = {12341-12348}, abstract = {

Five distinctly resolved O-17 solid-state NMR resonances in room temperature coesite, an SiO2 polymorph, have been observed and assigned using dynamic-angle spinning (DAS) at 11.7 T along with magic-angle spinning (MAS) spectra at 9.4 and 11.7 T. The O-17 quadrupolar parameters for each of the five oxygen environments in coesite are correlated with the Si-O-Si bridging bond angles determined by diffraction experiments. The sign of e(2)qQ/h along with the orientation of the electric field gradient for oxygen in the Si-O-Si linkage were determined from a Townes-Dailey analysis of the data.

}, keywords = {oxygen}, isbn = {0022-3654}, doi = {Doi 10.1021/J100032a045}, url = {://WOS:A1995RN70600045}, author = {Grandinetti, P. J. and Baltisberger, J. H. and Farnan, I. and Stebbins, J. F. and Werner, U. and Pines, A.} } @article {439, title = {Spin-Polarized Xe-129 Gas Imaging of Materials}, journal = {Journal of Magnetic Resonance Series A}, volume = {115}, year = {1995}, note = {J Magn Reson Ser ARl474Times Cited:49Cited References Count:23}, month = {Jul}, pages = {127-130}, keywords = {xenon}, isbn = {1064-1858}, doi = {Doi 10.1006/Jmra.1995.1157}, url = {://WOS:A1995RL47400017}, author = {Song, Y. Q. and Gaede, H. C. and Pietrass, T. and Barrall, G. A. and Chingas, G. C. and Ayers, M. R. and Pines, A.} } @article {464, title = {2-Dimensional Xe-129 Exchange Nmr Measurements of Xenon Dynamics in Na-a Zeolite}, journal = {Zeolites and Related Microporous Materials: State of the Art 1994}, volume = {84}, year = {1994}, note = {Stud Surf Sci CatalPart a-CBd02eTimes Cited:3Cited References Count:21Studies in Surface Science and Catalysis}, pages = {519-526}, abstract = {Two-dimensional (2D) exchange NMR is a powerful tool for measuring the dynamics and energetics of adsorbed xenon atoms undergoing slow exchange between the alpha-cages of Na-A zeolite. In this proceedings, we present recently published results, as well as additional discussion and data obtained, using 2D Xe-129 NMR to determine rate coefficients for intercage xenon hopping and to correlate them with adsorption and activation energies. Variable-temperature experiments establish the activation energy for hopping between alpha-cages to be 60+/-10 kJ/mol. The dependence of these kinetic and thermodynamic quantities on xenon occupancy of the alpha-cages reflects the importance of intracage interactions on the behavior of the adsorbed guest molecules.}, keywords = {cavities}, isbn = {0167-2991}, url = {://WOS:A1994BD02E00063}, author = {Janicke, M. and Chmelka, B. F. and Larsen, R. G. and Shore, J. and Schmidt-Rohr, K. and Emsley, L. and Long, H. and Pines, A.} } @article {461, title = {3-Dimensional Variable-Angle Nuclear-Magnetic-Resonance Exchange Spectroscopy without Rotor Axis Hopping}, journal = {Journal of Chemical Physics}, volume = {101}, year = {1994}, note = {J Chem PhysNy002Times Cited:12Cited References Count:48}, month = {Aug 1}, pages = {1852-1864}, abstract = {

Slow, large-amplitude chain motions play an important role in determining the macroscopic mechanical properties of polymers. Although such motions have been studied quantitatively by two-dimensional (2D) nuclear: magnetic resonance (NMR) exchange experiments, overlapping anisotropic patterns hamper spectral analysis, and limit applications. Variable angle correlation spectroscopy (VACSY) has proven useful in resolving such problems for rapidly spinning samples by separating anisotropic spectral patterns according to isotropic chemical shifts. In a previous study [J. Am. Chem. Sec. 115, 4825 (1993)], we described a three-dimensional (3D) NMR experiment that incorporates; the VACSY method and a hop of the rotor axis to correlate the isotropic chemical shifts to 2D anisotropic exchange patterns. The hop of the rotor axis, however, presents experimental difficulties and limits the range of motional rates that may be studied. We present in this paper a new 3D VACSY exchange experiment that obtains the same correlations without the need for the rotor axis hop. A series of 2D exchange spectra are recorded with the sample spinning at different rotation axis angles.\&$\#$39; Then using the scaling of the anisotropic frequency at the different angles, we construct the data onto a 3D matrix so that a Fourier transformation directly yields the desired correlations. The technique is applied to C-13 exchange NMR to study the slow molecular motion of ordered isotactic polypropylene.

}, keywords = {distributions}, isbn = {0021-9606}, doi = {Doi 10.1063/1.467696}, url = {://WOS:A1994NY00200011}, author = {Lee, Y. K. and Emsley, L. and Larsen, R. G. and Schmidt-Rohr, K. and Hong, M. and Frydman, L. and Chingas, G. C. and Pines, A.} } @inbook {466, title = {Group Theory and Nuclear Magnetic Resonance Dynamics}, booktitle = {NMR and More - In Honour of Anatole Abragam}, year = {1994}, pages = {175-199}, publisher = {Les Editions de Physique}, organization = {Les Editions de Physique}, author = {Emsley, L. and Schmidt-Rohr, K. and Pines, A.}, editor = {Porneuf, M. Goldman and M.} } @article {459, title = {Multiple-Pulse Nuclear-Magnetic-Resonance of Optically Pumped Xenon in a Low Magnetic-Field}, journal = {Physical Review A}, volume = {50}, year = {1994}, note = {Phys Rev ANx001Times Cited:23Cited References Count:38}, month = {Jul}, pages = {567-574}, abstract = {

Multiple-pulse coherent averaging methods are used to increase the resolution and frequency range of optically pumped xenon NMR in nutation and point-by-point precession experiments. We observe quadrupolar splittings in Xe-131 spectra due to the macroscopic asymmetry of pumping cells similar to those reported previously, but with reduced demands on magnetic-field homogeneity. Cell treatment with hydrogen gas increases the quadrupolar splittings by a factor of 3 over bare Pyrex cells.

}, keywords = {ne-21}, isbn = {1050-2947}, doi = {Doi 10.1103/Physreva.50.567}, url = {://WOS:A1994NX00100070}, author = {Raftery, D. and Long, H. W. and Shykind, D. and Grandinetti, P. J. and Pines, A.} } @article {458, title = {Nmr Measurement of Resolved Heteronuclear Dipole Couplings in Liquid-Crystals and Lipids}, journal = {Journal of Physical Chemistry}, volume = {98}, year = {1994}, note = {J Phys Chem-UsNw531Times Cited:68Cited References Count:25}, month = {Jul 7}, pages = {6668-6670}, abstract = {

Simplified nuclear magnetic resonance (NMR) spectra of heteronuclear dipolar couplings for molecules in an anisotropic environment, such as liquid crystals and lipids, are obtained by proton-detected local-field spectroscopy. The distance-dependent dipolar interactions between spins of magnetically active nuclei can be determined directly from the spectrum because many-body effects that complicate conventional dipolar NMR spectra are avoided by selectively probing local fields produced by rare spins at the location of abundant spins. We employ the technique to resolve the carbon-proton dipolar couplings of benzene dissolved in a nematic liquid crystal and to measure phosphorus-proton couplings in lecithin in the L(alpha) phase to obtain constraints on the phosphocholine headgroup structure.

}, keywords = {solids}, isbn = {0022-3654}, doi = {Doi 10.1021/J100078a002}, url = {://WOS:A1994NW53100002}, author = {Schmidt-Rohr, K. and Nanz, D. and Emsley, L. and Pines, A.} } @article {457, title = {Theory and Exact-Solutions for Tyckos Zero-Field Nmr in High-Field}, journal = {Journal of Magnetic Resonance Series A}, volume = {109}, year = {1994}, note = {J Magn Reson Ser APb546Times Cited:5Cited References Count:27}, month = {Aug}, pages = {157-165}, abstract = {

A theory of zero-field NMR in high field (ZFHF-NMR) is described in terms of coherent averaging and irreducible tensors. The theory is used to determine analytical solutions for the parameters of the trajectory proposed and used by Tycko. A new pulse sequence is presented, and optimized solutions for dynamic-angle spinning, dynamic-angle hopping, and double-rotation versions of ZFHF-NMR are discussed. (C) 1994 Academic Press, Inc.

}, keywords = {solid-state nmr}, isbn = {1064-1858}, doi = {Doi 10.1006/Jmra.1994.1149}, url = {://WOS:A1994PB54600003}, author = {Sun, B. Q. and Pines, A.} } @article {462, title = {Xe-129 Nmr-Study of Tio2 (Anatase)-Supported V2o5 Catalysts}, journal = {Journal of Physical Chemistry}, volume = {98}, year = {1994}, note = {J Phys Chem-UsPk740Times Cited:19Cited References Count:61}, month = {Oct 6}, pages = {10173-10179}, abstract = {

TiO2 (anatase), V2O5, and V2O5/TiO2 (anatase) catalysts with 1.3\%, 3.0\%, and 9.8\% weight loadings of V2O5 have been studied using temperature-dependent xenon-129 NMR spectroscopy. The intrinsic chemical shift values due to the interaction of xenon with the surface are 109 +/- 3 ppm for TiO2 (anatase) and 93 +/- 5 ppm for V2O5. The V2O5/TiO2 catalysts provide strong adsorption sites for xenon which cause an initial decrease of the chemical shift values at low xenon loadings. Additionally, the spectra of pure V2O5 reveal two distinct environments for the xenon atoms, consistent with the hysteresis of the isotherm and the existence of pores. Two-dimensional exchange spectroscopy was used to measure the rates and activation energy of xenon moving between these two environments.

}, keywords = {nay zeolite}, isbn = {0022-3654}, doi = {Doi 10.1021/J100091a037}, url = {://WOS:A1994PK74000037}, author = {Kritzenberger, J. and Gaede, H. C. and Shore, J. S. and Pines, A. and Bell, A. T.} } @proceedings {460, title = {Yakir Aharonov: From A to B}, journal = {Proc. of the Int. Conf. on Fundamental Aspects of Quantum Theory}, year = {1994}, publisher = {World Scientific}, author = {Pines, A.}, editor = {Anandan, J. and Safko, J.} } @article {473, title = {2-Dimensional Proton Nmr-Studies of the Conformations and Orientations of N-Alkanes in a Liquid-Crystal Solvent}, journal = {Journal of Physical Chemistry}, volume = {97}, year = {1993}, note = {J Phys Chem-UsKx596Times Cited:37Cited References Count:20}, month = {Apr 15}, pages = {3858-3866}, abstract = {

Magnetic dipole couplings between pairs of protons in a series of n-alkanes (hexane through decane) dissolved in a nematic liquid crystal were measured by two-dimensional NMR spectroscopy. The dependence of dipole couplings on the distance between pairs of protons and on the orientation of the molecule with respect to the applied magnetic field make them a potentially rich source of information about molecular conformation and orientation. Interpretation of the dipole couplings, however, is complicated by the fact that the measured couplings are averaged over all molecular conformations and orientations sampled by the molecule. Thus, the couplings do not directly provide internuclear distances and orientations, but instead provide constraints on the time-averaged conformations and orientations of the n-alkane molecules that can be used as a rigorous test of models for intermolecular interactions in liquid crystals. Three models for solute-liquid crystal interactions were examined; the model proposed by Photinos et al.1 was found to be superior to the others in describing this system. The results of the modeling, including order parameters and conformer probabilities for the alkanes, are discussed and compared to n-alkanes in the liquid state.

}, keywords = {size}, isbn = {0022-3654}, doi = {Doi 10.1021/J100117a037}, url = {://WOS:A1993KX59600037}, author = {Rosen, M. E. and Rucker, S. P. and Schmidt, C. and Pines, A.} } @article {472, title = {An Approximate Method of Side-Band Intensity Calculation in Magic-Angle-Spinning Nmr}, journal = {Applied Magnetic Resonance}, volume = {5}, year = {1993}, note = {Appl Magn ResonLv192Times Cited:2Cited References Count:19}, pages = {43-61}, abstract = {

A theory of sideband intensity is derived by expanding into a Taylor series the free induction decay observed under magic angle spinning (MAS). According to this procedure, the free induction decay signal is completely represented by a basis of irreducible tensors from rank zero to rank infinity. After averaging over all orientations, only the zero-order irreducible tensors contribute to the sideband intensities. Symmetry properties of the sidebands can be seen clearly in this expansion, and an approximate formula up to ninth order is obtained by truncating the series. Sideband intensities can be calculated rapidly with this formula. The results agree satisfactorily with the exact sideband intensities obtained by numerical simulation if the ratio of the anisotropy to the spinning speed, omega0delta/omega(r), is smaller than 3. The relationship of the sideband intensities with the moments of a MAS spectrum shows that the proposed method is an alternative to moment analysis when the spinning speed is not very slow. Anisotropic information about the chemical shift anisotropy interaction therefore can be extracted efficiently from experimental spectra by this approximate method.

}, keywords = {nuclei}, isbn = {0937-9347}, url = {://WOS:A1993LV19200006}, author = {Sun, B. Q. and Pines, A.} } @article {470, title = {Effects of Double Rotation on Homonuclear Spin Systems}, journal = {Journal of Magnetic Resonance Series A}, volume = {102}, year = {1993}, note = {J Magn Reson Ser AKz354Times Cited:3Cited References Count:13}, month = {Mar}, pages = {29-33}, keywords = {solids}, isbn = {1064-1858}, doi = {Doi 10.1006/Jmra.1993.1064}, url = {://WOS:A1993KZ35400005}, author = {Wu, Y. and Peng, Z. Y. and Olejniczak, Z. and Sun, B. Q. and Pines, A.} } @article {475, title = {High-Field Cross-Polarization Nmr from Laser-Polarized Xenon to a Polymer Surface}, journal = {Journal of the American Chemical Society}, volume = {115}, year = {1993}, note = {J Am Chem SocLx752Times Cited:77Cited References Count:16}, month = {Sep 8}, pages = {8491-8492}, keywords = {gas}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja00071a086}, url = {://WOS:A1993LX75200086}, author = {Long, H. W. and Gaede, H. C. and Shore, J. and Reven, L. and Bowers, C. R. and Kritzenberger, J. and Pietrass, T. and Pines, A. and Tang, P. and Reimer, J. A.} } @article {476, title = {Nmr-Study of Xenon Dynamics and Energetics in Na-a Zeolite}, journal = {Chemical Physics Letters}, volume = {214}, year = {1993}, note = {Chem Phys LettMd614Times Cited:56Cited References Count:22}, month = {Oct 29}, pages = {220-226}, abstract = {

For xenon atoms adsorbed in Na-A zeolite, electronic interactions cause shifts in NMR frequencies, resulting in a spectrum with discrete peaks from xenon atoms in cages with different xenon occupancies. Using two-dimensional exchange NMR, it is possible to determine the microscopic rates of intercage motion and to relate them to the adsorption and activation energies of the xenon atoms. The dependence of the adsorption energies on xenon cage occupancy reflects the importance of the intercage interactions and is directly related to the cage occupancy distribution. Variable temperature measurements yield an activation energy of about 60 kJ/mol for the transfer of a xenon from one cage to another.

}, keywords = {xe}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(93)90085-F}, url = {://WOS:A1993MD61400015}, author = {Larsen, R. G. and Shore, J. and Schmidt-Rohr, K. and Emsley, L. and Long, H. and Pines, A. and Janicke, M. and Chmelka, B. F.} } @article {477, title = {Side-Band Patterns in Dynamic-Angle-Spinning Nmr}, journal = {Journal of Magnetic Resonance Series A}, volume = {102}, year = {1993}, note = {J Magn Reson Ser AKz480Times Cited:19Cited References Count:26}, month = {Apr}, pages = {195-204}, keywords = {samples}, isbn = {1064-1858}, doi = {Doi 10.1006/Jmra.1993.1091}, url = {://WOS:A1993KZ48000011}, author = {Grandinetti, P. J. and Lee, Y. K. and Baltisberger, J. H. and Sun, B. Q. and Pines, A.} } @article {491, title = {Multiple-Quantum Nmr-Study of the Distribution of Benzene in Nay Zeolite}, journal = {Journal of Physical Chemistry}, volume = {96}, year = {1992}, note = {J Phys Chem-UsJu555Times Cited:26Cited References Count:24}, month = {Oct 15}, pages = {8517-8522}, abstract = {

We have used multiple-quantum NMR to measure the apparent spin network size as a function of excitation time of NaY zeolite samples containing varying amounts of benzene. Behavior observed at low concentrations of benzene was consistent with the presence of isolated clusters of benzene molecules in the supercages, with a statistical distribution of benzene molecules between supercages. Behavior observed at high concentrations of benzene was consistent with the presence of weakly coupled clusters of benzene molecules, with a uniform distribution of benzene molecules between supercages.

}, keywords = {solids}, isbn = {0022-3654}, doi = {Doi 10.1021/J100200a057}, url = {://WOS:A1992JU55500057}, author = {Pearson, J. G. and Chmelka, B. F. and Shykind, D. N. and Pines, A.} } @inbook {486, title = {New Angles in Motional Averaging}, booktitle = {Pulsed magnetic resonance: NMR, ESR and optics: A recognition of E.L. Hahn}, year = {1992}, pages = {80 - 94}, publisher = {Claredon Press}, organization = {Claredon Press}, chapter = {3}, address = {Oxford}, author = {Samoson, A. and Sun, B.Q. and Pines, A.}, editor = {Bagguley, D.M.S.} } @article {487, title = {Nmr-Studies of the Surface-Structure and Dynamics of Semiconductor Nanocrystals}, journal = {Chemical Physics Letters}, volume = {198}, year = {1992}, note = {Chem Phys LettJt385Times Cited:77Cited References Count:27}, month = {Oct 16}, pages = {431-436}, abstract = {

H-1 NMR studies of thiophenol capping groups on cadmium sulfide nanocrystals demonstrate that the coverage of the capping molecule depends on the size of the nanocrystal. Data are presented which show that as the size of the nanocrystal increases, the coverage of thiophenol decreases. In addition, information about the overall tumbling of the nanocrystal and the motion of the capping groups relative to the surface can be obtained from linewidth studies, indicating that the rotation of the capping groups is hindered in the smaller nanocrystals (r almost-equal-to 12 angstrom) and becomes less so in larger nanocrystals (r almost-equal-to 20 angstrom). The coverage data are related to the electronic properties of this important class of compounds.

}, keywords = {relaxation}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(92)80023-5}, url = {://WOS:A1992JT38500001}, author = {Sachleben, J. R. and Wooten, E. W. and Emsley, L. and Pines, A. and Colvin, V. L. and Alivisatos, A. P.} } @article {498, title = {Quantification of the Disorder in Network-Modified Silicate-Glasses}, journal = {Nature}, volume = {358}, year = {1992}, note = {NatureJb341Times Cited:169Cited References Count:32}, month = {Jul 2}, pages = {31-35}, abstract = {

Local order in silicate glasses has been observed by many experimental techniques to be similar to that in crystalline materials. Details of the intermediate-range order are more elusive, but essential for understanding the lack of long-range symmetry in glasses and the effect of composition on glass structure. Two-dimensional O-17 dynamic-angle-spinning nuclear magnetic resonance experiments reveal intermediate-range order in the distribution of inter-tetrahedral (Si-O-Si) bond angles and a high degree of order in the disposition of oxygen atoms around the network-modifying cations.

}, keywords = {time}, isbn = {0028-0836}, doi = {Doi 10.1038/358031a0}, url = {://WOS:A1992JB34100043}, author = {Farnan, I. and Grandinetti, P. J. and Baltisberger, J. H. and Stebbins, J. F. and Werner, U. and Eastman, M. A. and Pines, A.} } @article {485, title = {Sidebands in dynamic angle spinning (DAS) and double rotation (DOR) NMR}, journal = {Solid State Nuclear Magnetic Resonance}, volume = {1}, year = {1992}, note = {Solid State Nucl MagV26htTimes Cited:63Cited References Count:29}, month = {Dec}, pages = {267-295}, abstract = {

A theory of dynamic angle spinning (DAS) and double rotation (DOR) NMR is described using average Hamiltonian and irreducible tensor methods. Sideband intensities in DAS and DOR spectra are analyzed by both the moment and Bessel function methods, and general formulae are derived. Results show that the DAS moments depend on the relative rotor phase between the first and the second evolution periods, whereas the second and third DOR moments are independent of the relative phase between the inner and outer rotors. Sideband intensities in DAS spectra also depend on the relative rotor phases between evolution at the first and second angles, as well as on the ratio of time spent at each angle. Sideband intensities and phases in DOR spectra are related to the relative rotor phases between the inner and outer rotors, and the sideband pattern is determined by the ratio of the inner and outer rotor spinning speeds. An inversion symmetry of the odd numbered DOR sidebands at the relative rotor phase gamma(r) = 0 degrees. 180 degrees permits the elimination of these sidebands. Finally, numerical simulations are implemented and shown to agree with experimental results. Quadrupolar parameters can therefore be recovered either by calculating the second and third moments or by simulating the sideband intensities and phases.

}, keywords = {central transition}, isbn = {0926-2040}, doi = {Doi 10.1016/0926-2040(92)90047-D}, url = {://WOS:000208537400006}, author = {Sun, B. Q. and Baltisberger, J. H. and Wu, Y. and Samoson, A. and Pines, A.} } @article {504, title = {High-Resolution O-17 Nmr of Solid Silicates}, journal = {Journal of the American Chemical Society}, volume = {113}, year = {1991}, note = {J Am Chem SocEr082Times Cited:90Cited References Count:39}, month = {Jan 2}, pages = {32-38}, abstract = {

Several O-17-enriched silicates were studied by use of dynamic angle spinning (DAS) and double rotation (DOR) nuclear magnetic resonance spectroscopy. These methods average away second-order quadrupolar interactions by reorienting a sample about a time-dependent axis, thereby yielding high-resolution spectra of oxygen-17 nuclei. A narrow spectral line is observed for each distinct oxygen site at the sum of the isotropic chemical shift and the field-dependent isotropic second-order quadrupolar shift. Resolution is increased by up to 2 orders of magnitude compared to conventional magic angle spinning (MAS) spectra. Crystallographically inequivalent oxygens are now observable as distinct resonances in spectra of polycrystalline silicates such as diopside (CaMgSi2(17)O6), wollastonite (CaSi17O3), clinoenstatite (MgSi17O3), larnite (Ca2Si17O4),and forsterite (Mg2Si17O4).

}, keywords = {spectra}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja00001a006}, url = {://WOS:A1991ER08200006}, author = {Mueller, K. T. and Wu, Y. and Chmelka, B. F. and Stebbins, J. and Pines, A.} } @article {507, title = {Scaling and Time-Reversal of Spin Couplings in Zero-Field Nmr}, journal = {Physical Review Letters}, volume = {67}, year = {1991}, note = {Phys Rev LettGj319Times Cited:13Cited References Count:25}, month = {Oct 7}, pages = {1989-1992}, abstract = {

We report the observation of spin echoes resulting from the time reversal of isotropic many-body spin couplings in zero-field NMR. The coherent-averaging pulse sequences responsible for the scaling and the time reversal of isotropic interactions of first and second rank are based on cubic and icosahedral symmetry.

}, keywords = {nqr}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.67.1989}, url = {://WOS:A1991GJ31900014}, author = {Llor, A. and Olejniczak, Z. and Sachleben, J. and Pines, A.} } @article {522, title = {2-Dimensional Nmr-Studies of Flexible Molecules in Liquid-Crystals - Orientational Order and Conformational Probabilities of N-Hexane}, journal = {Molecular Physics}, volume = {69}, year = {1990}, note = {Mol PhysCy544Times Cited:38Cited References Count:55}, month = {Mar}, pages = {671-695}, isbn = {0026-8976}, doi = {Doi 10.1080/00268979000100501}, url = {://WOS:A1990CY54400007}, author = {Gochin, M. and Pines, A. and Rosen, M. E. and Rucker, S. P. and Schmidt, C.} } @article {521, title = {Dynamic-Angle Spinning of Quadrupolar Nuclei}, journal = {Journal of Magnetic Resonance}, volume = {86}, year = {1990}, note = {J Magn ResonCu525Times Cited:288Cited References Count:32}, month = {Feb 15}, pages = {470-487}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(90)90025-5}, url = {://WOS:A1990CU52500003}, author = {Mueller, K. T. and Sun, B. Q. and Chingas, G. C. and Zwanziger, J. W. and Terao, T. and Pines, A.} } @article {517, title = {A Fast, Stable Quadrature Phase Generator for Multiple-Pulse Nmr}, journal = {Review of Scientific Instruments}, volume = {61}, year = {1990}, note = {Rev Sci InstrumDc425Times Cited:8Cited References Count:14}, month = {May}, pages = {1474-1479}, isbn = {0034-6748}, doi = {Doi 10.1063/1.1141155}, url = {://WOS:A1990DC42500016}, author = {Shykind, D. N. and Chingas, G. C. and Pines, A. and Shaka, A. J.} } @article {514, title = {Nmr Experiments with a New Double Rotor}, journal = {Journal of Magnetic Resonance}, volume = {89}, year = {1990}, note = {J Magn ResonDu813Times Cited:113Cited References Count:13}, month = {Sep}, pages = {297-309}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(90)90236-3}, url = {://WOS:A1990DU81300008}, author = {Wu, Y. and Sun, B. Q. and Pines, A. and Samoson, A. and Lippmaa, E.} } @booklet {549, title = {Double Rotor for Solid-State Nmr}, journal = {Review of Scientific Instruments}, volume = {60}, year = {1989}, note = {Rev Sci InstrumAu005Times Cited:54Cited References Count:12}, month = {Oct}, pages = {3239-3241}, isbn = {0034-6748}, doi = {Doi 10.1063/1.1140558}, url = {://WOS:A1989AU00500021}, author = {Samoson, A. and Pines, A.} } @article {552, title = {Frequency Selective Nmr Pulse Sequences Generated by Iterative Schemes with Multiple Fixed-Points}, journal = {Molecular Physics}, volume = {67}, year = {1989}, note = {Mol PhysAf151Times Cited:3Cited References Count:24}, month = {Jun 20}, pages = {505-516}, isbn = {0026-8976}, doi = {Doi 10.1080/00268978900101251}, url = {://WOS:A1989AF15100003}, author = {Cho, H. and Mueller, K. T. and Shaka, A. J. and Pines, A.} } @article {554, title = {O-17 Nmr in Solids by Dynamic-Angle Spinning and Double Rotation}, journal = {Nature}, volume = {339}, year = {1989}, note = {NatureU4451Times Cited:177Cited References Count:15}, month = {May 4}, pages = {42-43}, isbn = {0028-0836}, doi = {Doi 10.1038/339042a0}, url = {://WOS:A1989U445100054}, author = {Chmelka, B. F. and Mueller, K. T. and Pines, A. and Stebbins, J. and Wu, Y. and Zwanziger, J. W.} } @article {550, title = {Suppression of the Zero Frequency Peak in Zero-Field Nmr}, journal = {Chemical Physics Letters}, volume = {158}, year = {1989}, note = {Chem Phys LettAb503Times Cited:1Cited References Count:22}, month = {Jun 9}, pages = {325-328}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(89)87345-2}, url = {://WOS:A1989AB50300029}, author = {Jarvie, T. P. and Takegoshi, K. and Suter, D. and Pines, A. and Zax, D. B.} } @article {559, title = {Broad-Band Heteronuclear Spin Decoupling in Solids}, journal = {Chemical Physics Letters}, volume = {144}, year = {1988}, note = {Chem Phys LettM4326Times Cited:19Cited References Count:11}, month = {Mar 4}, pages = {324-327}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(88)87122-7}, url = {://WOS:A1988M432600002}, author = {Suter, D. and Pines, A. and Lee, J. H. and Drobny, G.} } @article {568, title = {Diffusive Motion in Alkali Silicate Melts - an Nmr-Study at High-Temperature}, journal = {Geochimica Et Cosmochimica Acta}, volume = {52}, year = {1988}, note = {Geochim Cosmochim AcM3100Times Cited:79Cited References Count:67}, month = {Feb}, pages = {527-538}, isbn = {0016-7037}, doi = {Doi 10.1016/0016-7037(88)90108-1}, url = {://WOS:A1988M310000028}, author = {Liu, S. B. and Stebbins, J. F. and Schneider, E. and Pines, A.} } @article {565, title = {High-Resolution Solid-State Nmr Averaging of 2nd-Order Effects by Means of a Double-Rotor}, journal = {Molecular Physics}, volume = {65}, year = {1988}, note = {Mol PhysR5253Times Cited:405Cited References Count:34}, month = {Nov}, pages = {1013-1018}, isbn = {0026-8976}, doi = {Doi 10.1080/00268978800101571}, url = {://WOS:A1988R525300018}, author = {Samoson, A. and Lippmaa, E. and Pines, A.} } @article {563, title = {Iterative Carr-Purcell Trains}, journal = {Journal of Magnetic Resonance}, volume = {77}, year = {1988}, note = {J Magn ResonN4561Times Cited:39Cited References Count:13}, month = {May}, pages = {606-611}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(88)90022-4}, url = {://WOS:A1988N456100022}, author = {Shaka, A. J. and Rucker, S. P. and Pines, A.} } @article {564, title = {Iterative Schemes for Bilinear Operators - Application to Spin Decoupling}, journal = {Journal of Magnetic Resonance}, volume = {77}, year = {1988}, note = {J Magn ResonN1647Times Cited:752Cited References Count:31}, month = {Apr}, pages = {274-293}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(88)90178-3}, url = {://WOS:A1988N164700006}, author = {Shaka, A. J. and Lee, C. J. and Pines, A.} } @article {562, title = {Multiple-Pulse Sequences for Precise Transmitter Phase Alignment}, journal = {Journal of Magnetic Resonance}, volume = {80}, year = {1988}, note = {J Magn ResonQ6187Times Cited:10Cited References Count:33}, month = {Oct 15}, pages = {96-111}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(88)90060-1}, url = {://WOS:A1988Q618700008}, author = {Shaka, A. J. and Shykind, D. N. and Chingas, G. C. and Pines, A.} } @article {561, title = {Phase-Incremented Multiple-Quantum Nmr Experiments}, journal = {Journal of Magnetic Resonance}, volume = {76}, year = {1988}, note = {J Magn ResonL9552Times Cited:49Cited References Count:17}, month = {Jan}, pages = {149-154}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(88)90209-0}, url = {://WOS:A1988L955200015}, author = {Shykind, D. N. and Baum, J. and Liu, S. B. and Pines, A.} } @article {567, title = {A Si-29 Nuclear Magnetic-Resonance Study of Silicon-Aluminum Ordering in Leucite and Analcite}, journal = {Physics and Chemistry of Minerals}, volume = {15}, year = {1988}, note = {Phys Chem MinerM6832Times Cited:44Cited References Count:39}, pages = {370-382}, isbn = {0342-1791}, doi = {Doi 10.1007/Bf00311042}, url = {://WOS:A1988M683200009}, author = {Murdoch, J. B. and Stebbins, J. F. and Carmichael, I. S. E. and Pines, A.} } @article {560, title = {Study of the Aharonov-Anandan Quantum Phase by Nmr Interferometry}, journal = {Physical Review Letters}, volume = {60}, year = {1988}, note = {Phys Rev LettM6160Times Cited:184Cited References Count:43}, month = {Mar 28}, pages = {1218-1220}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.60.1218}, url = {://WOS:A1988M616000003}, author = {Suter, D. and Mueller, K. T. and Pines, A.} } @article {579, title = {Berry Phase in Magnetic-Resonance}, journal = {Molecular Physics}, volume = {61}, year = {1987}, note = {Mol PhysK2154Times Cited:90Cited References Count:47}, month = {Aug 20}, pages = {1327-1340}, isbn = {0026-8976}, doi = {Doi 10.1080/00268978700101831}, url = {://WOS:A1987K215400001}, author = {Suter, D. and Chingas, G. C. and Harris, R. A. and Pines, A.} } @article {582, title = {Broad-Band Heteronuclear Decoupling in the Presence of Homonuclear Dipolar and Quadrupolar Interactions}, journal = {Journal of Magnetic Resonance}, volume = {73}, year = {1987}, note = {J Magn ResonH7285Times Cited:40Cited References Count:31}, month = {Jun 1}, pages = {99-113}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(87)90228-9}, url = {://WOS:A1987H728500009}, author = {Schenker, K. V. and Suter, D. and Pines, A.} } @article {577, title = {Multiple Quantum Nmr Excitation with a One-Quantum Hamiltonian}, journal = {Chemical Physics}, volume = {114}, year = {1987}, note = {Chem PhysH4338Times Cited:45Cited References Count:16}, month = {May 15}, pages = {103-109}, isbn = {0301-0104}, doi = {Doi 10.1016/0301-0104(87)80023-X}, url = {://WOS:A1987H433800010}, author = {Suter, D. and Liu, S. B. and Baum, J. and Pines, A.} } @article {578, title = {Observation of Spin Diffusion in Zero-Field Magnetic-Resonance}, journal = {Physical Review Letters}, volume = {59}, year = {1987}, note = {Phys Rev LettH9613Times Cited:4Cited References Count:15}, month = {Jul 6}, pages = {106-108}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.59.106}, url = {://WOS:A1987H961300028}, author = {Suter, D. and Jarvie, T. P. and Sun, B. and Pines, A.} } @article {576, title = {Recursive Evaluation of Interaction Pictures}, journal = {Journal of Magnetic Resonance}, volume = {75}, year = {1987}, note = {J Magn ResonL8015Times Cited:1Cited References Count:8}, month = {Dec}, pages = {509-512}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(87)90106-5}, url = {://WOS:A1987L801500011}, author = {Suter, D. and Pines, A.} } @article {589, title = {Relaxation Mechanisms and Effects of Motion in Albite (Naalsi3o8) Liquid and Glass - a High-Temperature Nmr-Study}, journal = {Physics and Chemistry of Minerals}, volume = {15}, year = {1987}, note = {Phys Chem MinerL0167Times Cited:40Cited References Count:57}, pages = {155-162}, isbn = {0342-1791}, doi = {Doi 10.1007/Bf00308778}, url = {://WOS:A1987L016700007}, author = {Liu, S. B. and Pines, A. and Brandriss, M. and Stebbins, J. F.} } @article {581, title = {Speciation and Local-Structure in Alkali and Alkaline-Earth Silicate-Glasses - Constraints from Si-29 Nmr-Spectroscopy}, journal = {Journal of Non-Crystalline Solids}, volume = {89}, year = {1987}, note = {J Non-Cryst SolidsG5155Times Cited:74Cited References Count:46}, month = {Mar}, pages = {371-383}, isbn = {0022-3093}, doi = {Doi 10.1016/S0022-3093(87)80279-X}, url = {://WOS:A1987G515500011}, author = {Schneider, E. and Stebbins, J. F. and Pines, A.} } @article {580, title = {Symmetrical Phase-Alternating Composite Pulses}, journal = {Journal of Magnetic Resonance}, volume = {71}, year = {1987}, note = {J Magn ResonG3693Times Cited:74Cited References Count:28}, month = {Feb 15}, pages = {495-503}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(87)90249-6}, url = {://WOS:A1987G369300009}, author = {Shaka, A. J. and Pines, A.} } @article {575, title = {Theory of Broad-Band Heteronuclear Decoupling in Multispin Systems}, journal = {Journal of Magnetic Resonance}, volume = {73}, year = {1987}, note = {J Magn ResonH7285Times Cited:23Cited References Count:6}, month = {Jun 1}, pages = {90-98}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(87)90227-7}, url = {://WOS:A1987H728500008}, author = {Suter, D. and Schenker, K. V. and Pines, A.} } @article {590, title = {Theory of Multiple-Pulse Nmr at Low and Zero Fields}, journal = {Journal of Magnetic Resonance}, volume = {75}, year = {1987}, note = {J Magn ResonK7509Times Cited:14Cited References Count:18}, month = {Oct 15}, pages = {110-124}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(87)90318-0}, url = {://WOS:A1987K750900010}, author = {Lee, C. J. and Suter, D. and Pines, A.} } @article {603, title = {Defects and Short-Range Order in Nepheline Group Minerals - a Si-29 Nuclear-Magnetic-Resonance Study}, journal = {Physics and Chemistry of Minerals}, volume = {13}, year = {1986}, note = {Phys Chem MinerE6311Times Cited:40Cited References Count:61}, pages = {371-381}, isbn = {0342-1791}, url = {://WOS:A1986E631100003}, author = {Stebbins, J. F. and Murdoch, J. B. and Carmichael, I. S. E. and Pines, A.} } @article {609, title = {Determination of Dipole Dipole Couplings in Oriented Normal-Hexane by Two-Dimensional Nmr}, journal = {Journal of the American Chemical Society}, volume = {108}, year = {1986}, note = {J Am Chem SocE5180Times Cited:22Cited References Count:17}, month = {Oct 15}, pages = {6813-6814}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja00281a064}, url = {://WOS:A1986E518000064}, author = {Gochin, M. and Schenker, K. V. and Zimmermann, H. and Pines, A.} } @article {601, title = {Indirect Phase Detection of Nmr Spinor Transitions}, journal = {Physical Review Letters}, volume = {57}, year = {1986}, note = {Phys Rev LettD1256Times Cited:13Cited References Count:11}, month = {Jul 14}, pages = {242-244}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.57.242}, url = {://WOS:A1986D125600022}, author = {Suter, D. and Pines, A. and Mehring, M.} } @article {602, title = {New Probe for High-Temperature Nmr-Spectroscopy with Ppm Resolution}, journal = {Review of Scientific Instruments}, volume = {57}, year = {1986}, note = {Rev Sci InstrumAxa20Times Cited:15Cited References Count:19}, month = {Jan}, pages = {39-42}, isbn = {0034-6748}, doi = {Doi 10.1063/1.1139115}, url = {://WOS:A1986AXA2000010}, author = {Stebbins, J. F. and Schneider, E. and Murdoch, J. B. and Pines, A. and Carmichael, I. S. E.} } @article {619, title = {Composite Pulses without Phase-Distortion}, journal = {Journal of Magnetic Resonance}, volume = {61}, year = {1985}, note = {J Magn ResonAbv11Times Cited:124Cited References Count:37}, pages = {90-101}, isbn = {1090-7807}, doi = {Doi 10.1016/0022-2364(85)90270-7}, url = {://WOS:A1985ABV1100009}, author = {Tycko, R. and Cho, H. M. and Schneider, E. and Pines, A.} } @article {620, title = {A High-Temperature High-Resolution Nmr-Study of Na-23, Al-27 and Si-29 in Molten Silicates}, journal = {Nature}, volume = {314}, year = {1985}, note = {NatureAdt99Times Cited:58Cited References Count:13}, pages = {250-252}, isbn = {0028-0836}, doi = {Doi 10.1038/314250a0}, url = {://WOS:A1985ADT9900039}, author = {Stebbins, J. F. and Murdoch, J. B. and Schneider, E. and Carmichael, I. S. E. and Pines, A.} } @article {629, title = {Broad-Band Population-Inversion in Solid-State Nmr}, journal = {Journal of Chemical Physics}, volume = {81}, year = {1984}, note = {J Chem PhysTb783Times Cited:50Cited References Count:41}, pages = {680-688}, isbn = {0021-9606}, doi = {Doi 10.1063/1.447749}, url = {://WOS:A1984TB78300012}, author = {Tycko, R. and Schneider, E. and Pines, A.} } @article {627, title = {Differentiation between Al-27 Nuclei in Alums by Fourier-Transform Pure Nuclear-Quadrupole Resonance}, journal = {Nature}, volume = {312}, year = {1984}, note = {NatureTt555Times Cited:17Cited References Count:12}, pages = {351-352}, isbn = {0028-0836}, doi = {Doi 10.1038/312351a0}, url = {://WOS:A1984TT55500046}, author = {Zax, D. B. and Bielecki, A. and Pines, A. and Sinton, S. W.} } @article {632, title = {Multiple-Quantum Nmr-Study of Molecular-Structure and Ordering in a Liquid-Crystal}, journal = {Molecular Physics}, volume = {53}, year = {1984}, note = {Mol PhysTq351Times Cited:65Cited References Count:45}, pages = {333-362}, isbn = {0026-8976}, doi = {Doi 10.1080/00268978400102351}, url = {://WOS:A1984TQ35100007}, author = {Sinton, S. W. and Zax, D. B. and Murdoch, J. B. and Pines, A.} } @article {647, title = {Time-Resolved Optical Nuclear-Polarization by Rapid Field Switching}, journal = {Chemical Physics Letters}, volume = {93}, year = {1982}, note = {Chem Phys LettPv837Times Cited:4Cited References Count:15}, pages = {392-395}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(82)83716-0}, url = {://WOS:A1982PV83700018}, author = {Tycko, R. and Pines, A. and Stehlik, D.} } @article {655, title = {Dipolar Relaxation by Rotation in Spin Space}, journal = {Journal of Magnetic Resonance}, volume = {45}, year = {1981}, note = {J Magn ResonMk798Times Cited:7Cited References Count:28}, pages = {94-101}, isbn = {1090-7807}, doi = {Doi 10.1016/0022-2364(81)90103-7}, url = {://WOS:A1981MK79800009}, author = {Emid, S. and Smidt, J. and Pines, A.} } @article {656, title = {Selectivity in Multiple-Quantum Spectroscopy}, journal = {Philosophical Transactions of the Royal Society a-Mathematical Physical and Engineering Sciences}, volume = {299}, year = {1981}, note = {Philos T R Soc ALj669Times Cited:19Cited References Count:17}, pages = {585-592}, isbn = {1364-503X}, doi = {Doi 10.1098/Rsta.1981.0036}, url = {://WOS:A1981LJ66900008}, author = {Drobny, G. and Pines, A. and Sinton, S. and Warren, W. S. and Weitekamp, D. P.} } @article {660, title = {Anisotropic Spin-Lattice Relaxation of Deuterated Hexamethylbenzene}, journal = {Journal of Magnetic Resonance}, volume = {41}, year = {1980}, note = {J Magn ResonKx294Times Cited:25Cited References Count:7}, pages = {389-394}, isbn = {1090-7807}, doi = {Doi 10.1016/0022-2364(80)90294-2}, url = {://WOS:A1980KX29400004}, author = {Tang, J. and Sterna, L. and Pines, A.} } @article {659, title = {Double-Quantum Cross-Polarization Nmr in Solids}, journal = {Physical Review A}, volume = {22}, year = {1980}, note = {Phys Rev AKb812Times Cited:53Cited References Count:27}, pages = {638-661}, isbn = {1050-2947}, doi = {Doi 10.1103/Physreva.22.638}, url = {://WOS:A1980KB81200041}, author = {Vega, S. and Shattuck, T. W. and Pines, A.} } @article {667, title = {Selective Double-Quantum Nmr in Solids}, journal = {Chemical Physics Letters}, volume = {73}, year = {1980}, note = {Chem Phys LettKe433Times Cited:7Cited References Count:24}, pages = {496-499}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(80)80703-2}, url = {://WOS:A1980KE43300021}, author = {Emid, S. and Smidt, J. and Pines, A.} } @article {668, title = {On the short time behavior of the dipolar signal in relaxation measurements by the pulse method}, journal = {Physica}, year = {1980}, pages = {215-218}, author = {Emid, S. and Konijnendijk, J. and Schmidt, J. and Pines, A.} } @article {665, title = {Study of Liquid-Crystal Conformation by Multiple Quantum Nmr - Normal-Pentyl Cyanobiphenyl}, journal = {Chemical Physics Letters}, volume = {76}, year = {1980}, note = {Chem Phys LettKx693Times Cited:104Cited References Count:19}, pages = {263-267}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(80)87017-5}, url = {://WOS:A1980KX69300017}, author = {Sinton, S. and Pines, A.} } @article {664, title = {Viscosity and Temperature-Dependence of the Magnetic Isotope Effect}, journal = {Journal of Chemical Physics}, volume = {73}, year = {1980}, note = {J Chem PhysKx295Times Cited:53Cited References Count:35}, pages = {5493-5499}, isbn = {0021-9606}, doi = {Doi 10.1063/1.440068}, url = {://WOS:A1980KX29500010}, author = {Sterna, L. and Ronis, D. and Wolfe, S. and Pines, A.} } @article {674, title = {Multiple Quantum Coherence in Dipolar Relaxation Measurements}, journal = {Physica B \& C}, volume = {96}, year = {1979}, note = {Physica B \& CHb239Times Cited:26Cited References Count:9}, pages = {333-336}, isbn = {0378-4371}, doi = {Doi 10.1016/0378-4363(79)90018-4}, url = {://WOS:A1979HB23900006}, author = {Emid, S. and Bax, A. and Konijnendijk, J. and Smidt, J. and Pines, A.} } @article {673, title = {Quantitative Aspects of Deuteron (Spin 1) Spin Decoupling in Solid-State Nmr}, journal = {Physical Review B}, volume = {19}, year = {1979}, note = {Phys Rev BGn686Times Cited:13Cited References Count:14}, pages = {238-246}, isbn = {0163-1829}, doi = {Doi 10.1103/Physrevb.19.238}, url = {://WOS:A1979GN68600029}, author = {Suwelack, D. and Mehring, M. and Pines, A.} } @article {672, title = {Selective Excitation of Multiple-Quantum Coherence in Nuclear Magnetic-Resonance}, journal = {Physical Review Letters}, volume = {43}, year = {1979}, note = {Phys Rev LettHw700Times Cited:85Cited References Count:14}, pages = {1791-1794}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.43.1791}, url = {://WOS:A1979HW70000008}, author = {Warren, W. S. and Sinton, S. and Weitekamp, D. P. and Pines, A.} } @article {676, title = {5-Quantum and 6-Quantum Nmr-Spectra of Oriented Benzene}, journal = {Bulletin of the American Physical Society}, volume = {23}, year = {1978}, note = {B Am Phys SocEg455Times Cited:27Cited References Count:3}, pages = {21-21}, isbn = {0003-0503}, url = {://WOS:A1978EG45500071}, author = {Pines, A. and Wemmer, D. and Tang, J. and Sinton, S.} } @article {679, title = {Fourier transform multiple quantum nuclear magnetic resonance}, journal = {Faraday Symposia of the Chemical Society}, volume = {13}, year = {1978}, pages = {49-55}, abstract = {

The excitation and detection of multiple quantum transitions in systems of coupled spins offers, among other advantages, an increase in resolution over single quantum n.m.r. since the number of lines decreases as the order of the transition increases. This paper reviews the motivation for detecting multiple quantum transitions by a Fourier transform experiment and describes an experimental approach to high resolution multiple quantum spectra in dipolar systems along with results on some protonated liquid crystal systems. A simple operator formalism for the essential features of the time development is presented and some applications in progress are discussed.

}, isbn = {0301-5696}, url = {http://dx.doi.org/10.1039/FS9781300049}, author = {Drobny, Gary and Pines, Alexander and Sinton, Steven and Weitekamp, Daniel P. and Wemmer, David} } @inbook {682, title = {Double quantum NMR in solids}, booktitle = {Magnetic Resonance in Condensed Matter: Recent developments}, year = {1977}, pages = {127-129}, publisher = {University of Ljubljana Press}, organization = {University of Ljubljana Press}, author = {Pines, A. and Vega, S. and Ruben, D.J. and Shattuck, T.W. and Wemmer, D.}, editor = {Lahajanr, R. Blinc and G.} } @article {685, title = {Dynamics of Spin Decoupling in Carbon-13-Proton Nmr}, journal = {Chemical Physics Letters}, volume = {43}, year = {1976}, note = {Chem Phys LettCk656Times Cited:35Cited References Count:19}, pages = {382-386}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(76)85325-0}, url = {://WOS:A1976CK65600042}, author = {Sinning, G. and Mehring, M. and Pines, A.} } @article {684, title = {Fourier-Transform Double-Quantum Nmr in Solids}, journal = {Physical Review Letters}, volume = {37}, year = {1976}, note = {Phys Rev LettBv563Times Cited:139Cited References Count:12}, pages = {43-46}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.37.43}, url = {://WOS:A1976BV56300013}, author = {Vega, S. and Shattuck, T. W. and Pines, A.} } @article {687, title = {Nmr Line Broadening in Solids by Slowing down of Spin Fluctuations}, journal = {Zeitschrift Fur Physik B-Condensed Matter}, volume = {24}, year = {1976}, note = {Z Phys B Con MatBs166Times Cited:23Cited References Count:13}, pages = {73-76}, isbn = {0722-3277}, doi = {Doi 10.1007/Bf01312875}, url = {://WOS:A1976BS16600009}, author = {Mehring, M. and Sinning, G. and Pines, A.} } @article {693, title = {C-13 Proton Nmr Cross-Polarization Times in Solid Adamantane}, journal = {Journal of Chemical Physics}, volume = {61}, year = {1974}, note = {J Chem PhysT7994Times Cited:44Cited References Count:16}, pages = {1255-1256}, isbn = {0021-9606}, doi = {Doi 10.1063/1.1682009}, url = {://WOS:A1974T799400079}, author = {Pines, A. and Shattuck, T. W.} } @article {702, title = {Simple Data Acquisition-System for Proton-Enhanced Nuclear Induction Spectroscopy}, journal = {Journal of Magnetic Resonance}, volume = {14}, year = {1974}, note = {J Magn ResonT4998Times Cited:2Cited References Count:7}, pages = {270-273}, isbn = {1090-7807}, doi = {Doi 10.1016/0022-2364(74)90283-2}, url = {://WOS:A1974T499800003}, author = {Merrick, T. and Smiriga, S. and Pines, A.} } @article {706, title = {Enhanced Inhomogeneous Nuclear Spin Echoes for Dilute Spins in Solids}, journal = {Chemical Physics Letters}, volume = {23}, year = {1973}, note = {Chem Phys LettS0678Times Cited:16Cited References Count:14}, pages = {614-616}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(73)89042-6}, url = {://WOS:A1973S067800042}, author = {Pines, A. and Shattuck, T. W.} } @article {1925, title = {Non-disruptive dissolution of hp-129Xe in viscou aqueous and organic liquid crystalline environments}, author = {Ashley E. Truxal and Clancy C. Slack and Muller D. Gomes and Christophoros C. Vassiliou and David E. Wemmer and Alexander Pines} }