@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 {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 {258, title = {Near-Zero-Field Nuclear Magnetic Resonance}, journal = {Physical Review Letters}, volume = {107}, year = {2011}, note = {Phys Rev Lett813YOTimes Cited:5Cited References Count:26}, month = {Sep 1}, abstract = {

We investigate nuclear magnetic resonance (NMR) in near zero field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J coupling). This is in stark contrast to the high-field case, where heteronuclear J couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectra. Experimental results are in good agreement with first-order perturbation theory and with full numerical simulation when perturbation theory breaks down. We present simple rules for understanding the splitting patterns in near-zero-field NMR, which can be applied to molecules with nontrivial spectra.

}, keywords = {mri}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.107.107601}, url = {://WOS:000294406600017}, author = {Ledbetter, M. P. and Theis, T. and Blanchard, J. W. and Ring, H. and Ganssle, P. and Appelt, S. and Blumich, B. and Pines, A. and Budker, D.} } @article {282, title = {NMR imaging of catalytic hydrogenation in microreactors with the use of para-hydrogen}, journal = {Science}, volume = {319}, year = {2008}, note = {Science254HBTimes Cited:55Cited References Count:33}, month = {Jan 25}, pages = {442-445}, abstract = {

Catalysis is vital to industrial chemistry, and the optimization of catalytic reactors attracts considerable resources. It has proven challenging to correlate the active regions in heterogeneous catalyst beds with morphology and to monitor multistep reactions within the bed. We demonstrate techniques, using magnetic resonance imaging and para- hydrogen ( p-H(2)) polarization, that allow direct visualization of gas- phase flow and the density of active catalyst in a packed- bed microreactor, as well as control over the dynamics of the polarized state in space and time to facilitate the study of subsequent reactions. These procedures are suitable for characterizing reactors and reactions in microfluidic devices where low sensitivity of conventional magnetic resonance would otherwise be the limiting factor.

}, keywords = {chip}, isbn = {0036-8075}, doi = {Doi 10.1126/Science.1151787}, url = {://WOS:000252576600031}, author = {Bouchard, L. S. and Burt, S. R. and Anwar, M. S. and Kovtunov, K. V. and Koptyug, I. V. and Pines, A.} } @article {303, title = {NMR velocity mapping of gas flow around solid objects}, journal = {Physical Review E}, volume = {74}, year = {2006}, note = {Phys Rev EPart 2069DJTimes Cited:4Cited References Count:31}, month = {Jul}, abstract = {

We present experimental visualizations of gas flow around solid blunt bodies by NMR imaging. NMR velocimetry is a model-free and tracer-free experimental means for quantitative and multi-dimensional flow visualization. Hyperpolarization of Xe-129 provided sufficient NMR signal to overcome the low density of the dilute gas phase, and its long coherence time allows for true velocity vector mapping. In this study, the diverging gas flow around and wake patterns immediately behind a sphere could be vectorally visualized and quantified. In a similar experiment, the flow over an aerodynamic model airplane body revealed a less disrupted flow pattern.

}, keywords = {wake}, isbn = {1539-3755}, doi = {Doi 10.1103/Physreve.74.016302}, url = {://WOS:000239425700044}, author = {Han, S. I. and Pierce, K. L. and Pines, A.} } @article {311, title = {NMR analysis on microfluidic devices by remote detection}, journal = {Analytical Chemistry}, volume = {77}, year = {2005}, note = {Anal Chem995DDTimes Cited:25Cited References Count:36}, month = {Dec 15}, pages = {8109-8114}, abstract = {

We present a novel approach to perform high-sensitivity NMR imaging and spectroscopic analysis on microfluidic devices. The application of NMR, the most information-rich spectroscopic technique, to microfluidic devices remains a challenge because the inherently low sensitivity of NMR is aggravated by small fluid volumes leading to low NMR signal and geometric constraints resulting in poor efficiency for inductive detection. We address the latter by physically separating signal detection from encoding of information with remote detection. Thereby, we use a commercial imaging probe with sufficiently large diameter to encompass the entire device, enabling encoding of NMR information at any location on the chip. Because large-diameter coils are too insensitive for detection, we store the encoded information as longitudinal magnetization and flow it into the outlet capillary. There, we detect the signal with optimal sensitivity, using a solenoidal microcoil, and reconstruct the information encoded in the fluid. We present a generally applicable design for a detection-only microcoil probe that can be inserted into the bore of a commercial imaging probe. Using hyperpolarized Xe-129 gas, we show that this probe enables sensitive reconstruction of NMR spectroscopic information encoded by the large imaging probe while keeping the flexibility of a large coil.

}, keywords = {probes}, isbn = {0003-2700}, doi = {Doi 10.1021/Ac051320+}, url = {://WOS:000234079200034}, author = {McDonnell, E. E. and Han, S. L. and Hilty, C. and Pierce, K. L. and Pines, A.} } @article {318, title = {NMR detection using laser-polarized xenon as a dipolar sensor}, journal = {Journal of Magnetic Resonance}, volume = {176}, year = {2005}, note = {J Magn Reson972AITimes Cited:14Cited References Count:46}, month = {Oct}, pages = {125-139}, abstract = {

Hyperpolarized Xe-129 can be used as a sensor to indirectly detect NMR spectra of heteronuclei that are neither covalently bound nor necessarily in direct contact with the Xe atoms, but coupled through long-range intermolecular dipole-dipole interactions. To reintroduce long-range dipolar couplings the sample symmetry has to be broken. This can be done either by using an asymmetric sample arrangement, or by breaking the symmetry of the spin magnetization with field gradient pulses. Experiments are performed where only a small fraction of the available Xe-129 magnetization is used for each point, so that a single batch of xenon suffices for the point-by-point acquisition of a heteronuclear NMR spectrum. Examples with H-1 as the analyte nucleus show that these methods have the potential to obtain spectra with a resolution that is high enough to determine homonuclear J couplings. The applicability of this technique with remote detection is discussed. Published by Elsevier Inc.

}, keywords = {dynamics}, isbn = {1090-7807}, doi = {Doi 10.1016/J.Jmr.2005.05.013}, url = {://WOS:000232425800001}, author = {Granwehr, J. and Urban, J. T. and Trabesinger, A. H. 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 {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 {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 {379, title = {NMR study of InP quantum dots: Surface structure and size effects}, journal = {Journal of Chemical Physics}, volume = {110}, year = {1999}, note = {J Chem Phys192HUTimes Cited:30Cited References Count:28}, month = {May 8}, pages = {8861-8864}, abstract = {

We report the results of P-31 NMR measurements on trioctylphosphine oxide (TOPO) passivated InP quantum dots. The spectra show distinct surface-capping sites, implying a manifold of crystal-ligand bonding configurations. Two In P-31 surface components are resolved and related to different electronic surroundings. With decreasing particle size the In P-31 core resonance reveals an increasing upfield chemical shift related to the overall size dependence of the InP electronic structure. (C) 1999 American Institute of Physics. [S0021-9606(99)70718-X].

}, keywords = {clusters}, isbn = {0021-9606}, doi = {Doi 10.1063/1.478858}, url = {://WOS:000080073200002}, author = {Tomaselli, M. and Yarger, J. L. and Bruchez, M. and Havlin, R. H. and deGraw, D. and Pines, A. and Alivisatos, A. P.} } @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 {396, title = {NMR of supercritical laser-polarized xenon}, journal = {Chemical Physics Letters}, volume = {292}, year = {1998}, note = {Chem Phys Lett112EZTimes Cited:25Cited References Count:35}, month = {Aug 14}, pages = {686-690}, abstract = {

The feasibility of producing supercritical laser-polarized xenon for nuclear magnetic resonance (NMR) investigations was studied. Using a high-pressure capillary tube, a supercritical xenon sample (52 degrees C, 65 atm) was produced with a Xe-129 polarization approximately 140 times the equilibrium value. The polarization was observed to last for hundreds of seconds, in agreement with previous studies. These preliminary results suggest that supercritical laser-polarized xenon may be used as a polarizing solvent for numerous NMR applications. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

}, keywords = {gas}, isbn = {0009-2614}, doi = {Doi 10.1016/S0009-2614(98)00732-5}, url = {://WOS:000075482300049}, author = {Haake, M. and Goodson, B. M. and Laws, D. D. and Brunner, E. and Cyrier, M. C. and Havlin, R. H. and Pines, A.} } @article {399, title = {NMR spectra with peaks at the principal values of the chemical shielding tensor}, journal = {Chemical Physics Letters}, volume = {285}, year = {1998}, note = {Chem Phys LettZf354Times Cited:10Cited References Count:25}, month = {Mar 13}, pages = {59-63}, abstract = {

The NMR chemical shielding in a solid powder sample produces featured, but broad, lineshapes, or powder patterns, because the shielding experienced by a nuclear spin depends on the spatial orientation of its local molecular frame with respect to the external magnetic field. The Lineshape, however, is fully determined by the three principal values of the shielding tenser. We present a simple approach that uses sample spinning NMR to extract peaks at the principal-value frequencies from chemical shielding powder patterns. Such techniques may simplify spectra with overlapping powder patterns without the information loss inherent in fast magic angle spinning. Experimental data and numerical simulations are presented for two P-31 model compounds. (C) 1998 Elsevier Science B.V.

}, keywords = {SPECTROSCOPY}, isbn = {0009-2614}, doi = {Doi 10.1016/S0009-2614(97)01478-4}, url = {://WOS:000072889100010}, author = {de Swiet, T. M. and Tomaselli, M. and Pines, A.} } @article {415, title = {A novel detection-estimation scheme for noisy NMR signals: Applications to delayed acquisition data}, journal = {Journal of Magnetic Resonance}, volume = {128}, year = {1997}, note = {J Magn ResonYc696Times Cited:47Cited References Count:59}, month = {Sep}, pages = {30-41}, abstract = {

Many potentially interesting and useful classes of NMR experiments generate data for which conventional spectral estimation and quantification aa the Fourier transform are unsatisfactory. In particular, recently introduced solid-state NMR experiments which involve long delays before data acquisition fall into this category, as the free induction decays are heavily \&$\#$39;\&$\#$39;truncated\&$\#$39;\&$\#$39; and have low signal-to-noise ratios. A novel detection-estimation scheme is introduced in order to analyze data from such experiments and others where the sensitivity is low and/or the data record is strongly damped or truncated, Based on the assumption of exponential data modeling, the number of signals present is first detected using criteria derived from information theory and the spectral parameters are then estimated using the matrix pencil method, Monte Carlo simulations and experimental. applications are carried out to demonstrate its superior statistical and computational performances and its general applicability to delayed acquisition data. Over the range of note levels investigated, it is found that this approach is essentially near-optimal in the sense that the estimated spectral parameters have biases almost equal to zero and variances very close to their theoretical Cramer-Rao lower bounds. Compared to the popular method of linear prediction with singular value decomposition, this method not only improves the estimation accuracy (by a factor of 2-4) with a lower \&$\#$39;\&$\#$39;break-down\&$\#$39;\&$\#$39; signal-to-noise threshold (approximate to 1.5 dB), but also reduces the computational cost by about an order of magnitude, It also holds great promise in effectively reducing truncation artifacts. It is concluded that this approach not only facilitates the analysis of delayed acquisition data, but can also become a valuable tool in the routine quantification of general NMR spectra, ia listing of programs is also included in the Appendix. (C) 1997 Academic Press.

}, keywords = {resolution}, isbn = {1090-7807}, doi = {Doi 10.1006/Jmre.1997.1215}, url = {://WOS:A1997YC69600004}, author = {Lin, Y. Y. and Hodgkinson, P. and Ernst, M. 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 {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 {456, title = {N-14 Squid Nqr of L-Ala-L-His and of Serine}, journal = {Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences}, volume = {49}, year = {1994}, note = {Z Naturforsch AQh740Times Cited:2Cited References Count:15}, month = {Dec}, pages = {1188-1192}, abstract = {N-14 nuclear quadrupole resonance spectroscopy, detected with a Superconducting Quantum Interference Device, makes possible the study of nitrogen environments in amino acids and small peptides. The present experiments characterize: 1) the effects of intermolecular interactions upon the amino nitrogen of serine upon cocrystallization of the stereoisomers in a range of concentrations; 2) the changes of the amino and imidazole nitrogen environments brought about by combining L-Alanine and L-Histidine into the dipeptide L-Ala-L-His.}, keywords = {n-14}, isbn = {0932-0784}, url = {://WOS:A1994QH74000013}, author = {Wernerzwanziger, U. and Ziegeweid, M. and Black, B. 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.} } @book {468, title = {NMR techniques in catalysis}, series = {Chemical industries}, year = {1994}, note = {93043400GLADN151159362edited by Alexis T. Bell, Alexander Pines.ill. ; 24 cm.Includes bibliographical references and index.Chemical industries ; v. 55.}, pages = {viii, 432 p.}, publisher = {M. Dekker}, organization = {M. Dekker}, address = {New York}, keywords = {Nuclear magnetic resonance spectroscopy.}, isbn = {0824791738 (acid-free)}, author = {Bell, A.T. and Pines, 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.} } @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 {484, title = {New Angles in Nuclear-Magnetic-Resonance Sample Spinning}, journal = {Accounts of Chemical Research}, volume = {25}, year = {1992}, note = {Accounts Chem ResHu248Times Cited:41Cited References Count:29}, month = {May}, pages = {209-215}, keywords = {axis}, isbn = {0001-4842}, doi = {Doi 10.1021/Ar00017a001}, url = {://WOS:A1992HU24800001}, author = {Wooten, E. W. and Mueller, K. T. and Pines, A.} } @article {489, title = {Nmr of Optically Pumped Xenon Thin-Films}, journal = {Chemical Physics Letters}, volume = {191}, year = {1992}, note = {Chem Phys LettHp501Times Cited:25Cited References Count:25}, month = {Apr 10}, pages = {385-390}, abstract = {

NMR of Xe-129 has been observed in thin films of xenon frozen onto the surfaces of glass sample cells with various geometries. The Xe-129 polarization was enhanced by optical pumping, and the xenon was then transferred to a high-field pulsed NMR spectrometer allowing the observation of strong signals from xenon films of approximately 1-mu-m thickness. The line shape depends on the film geometry because of the bulk diamagnetic susceptibility chi(D) of solid xenon. The spectral line shape and resonance frequency also depend on temperature.

}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(92)85396-R}, url = {://WOS:A1992HP50100002}, author = {Raftery, D. and Long, H. and Reven, L. and Tang, P. and Pines, A.} } @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 {506, title = {Nmr Probe for Dynamic-Angle Spinning}, journal = {Review of Scientific Instruments}, volume = {62}, year = {1991}, note = {Rev Sci InstrumFp312Times Cited:31Cited References Count:35}, month = {Jun}, pages = {1445-1452}, abstract = {

We describe the design of a probe for dynamic-angle spinning (DAS) NMR experiments, comprised of a spinning cylindrical sample holder whose axis may be reoriented rapidly between discrete directions within the bore of a superconducting magnet. This allows the refocusing of nuclear spin magnetization that evolves under anisotropic interactions such as chemical shift anisotropy and quadrupolar coupling, providing high resolution NMR spectra for quadrupolar nuclei in solid materials. The probe includes an axial air delivery system to bearing and drive jets which support and spin a rotor containing the sample. Axis reorientation is accomplished with a pulley attached to the probehead and coupled to a stepping motor outside of the magnet. The choice of motor and gear ratio is based on an analysis of the moments of inertia of the motor and load, the desired angular resolution, and simplicity of design. Control of angular accuracy and precision are discussed, as well as the efficiency of radiofrequency irradiation and detection. High resolution DAS spectra of oxygen-17 and aluminum-27 nuclei in polycrystalline minerals illustrate the experimental capabilities.

}, keywords = {minerals}, isbn = {0034-6748}, doi = {Doi 10.1063/1.1142465}, url = {://WOS:A1991FP31200011}, author = {Mueller, K. T. and Chingas, G. C. and Pines, A.} } @article {511, title = {Nmr-Study of the Distribution of Aromatic-Molecules in Nay Zeolite}, journal = {Journal of Physical Chemistry}, volume = {95}, year = {1991}, note = {J Phys Chem-UsEr473Times Cited:70Cited References Count:64}, month = {Jan 10}, pages = {303-310}, abstract = {

Local and macroscopic distributions of adsorbed benzene, 1,3,5-trimethylbenzene, and hexamethylbenzene (HMB) molecules among the intracrystalline of NaY zeolite samples have been investigated by Xe-129 and multiple-quantum NMR. Xenon-129 NMR, a sensitive probe of macroscopic distributions of molecules in zeolites at room temperature, demonstrates the importance of sample heat treatment in distributing an adsorbate homogeneously throughout a collection of zeolite particles. NaY samples containing organic guests adsorbed a temperatures near the bulk species\&$\#$39; melting point produce multiple or broad xenon lines characteristic of macroscopic (i.e., interparticle) adsorbate concentration gradients. After thorough heat treatment of the samples at elevated temperatures, the xenon spectrum collapses to a single sharp line, consistent with a macroscopically uniform distribution. For HMB adsorbed in NaY, \"counting\" hydrogen clusters by multiple-quantum NMR reveals intraparticle HMB distributions consistent with one molecular per cavity at low loadings (average bulk loading less-than-or-equal-to 1 molecule per cavity) and two molecules per cavity at higher loadings.

}, keywords = {catalysts}, isbn = {0022-3654}, doi = {Doi 10.1021/J100154a056}, url = {://WOS:A1991ER47300056}, author = {Chmelka, B. F. and Pearson, J. G. and Liu, S. B. and Ryoo, R. and Demenorval, L. C. and Pines, A.} } @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.} } @article {520, title = {NMR in physics, chemistry and biology: Illustrations of Bloch{\textquoteright}s legacy in proceedings of the Bloch symposium}, journal = {International Journal of Modern Physics B}, volume = {4}, year = {1990}, pages = {1241-1267}, author = {Pines, A.} } @article {512, title = {Non-Abelian Effects in a Quadrupole System Rotating around 2 Axes}, journal = {Physical Review A}, volume = {42}, year = {1990}, note = {Phys Rev ADy007Times Cited:30Cited References Count:22}, month = {Sep 1}, pages = {3107-3110}, isbn = {1050-2947}, doi = {Doi 10.1103/Physreva.42.3107}, url = {://WOS:A1990DY00700066}, author = {Zwanziger, J. W. and Koenig, M. and Pines, A.} } @article {518, title = {Nuclear Magnetic Resonance}, journal = {Spectroscopy}, volume = {5}, year = {1990}, pages = {34-35}, author = {Pines, A. and Wu, Y.} } @article {557, title = {Non-Abelian Geometric Phase from Incomplete Quantum Measurements}, journal = {Physics Letters A}, volume = {141}, year = {1989}, note = {Phys Lett ACb816Times Cited:19Cited References Count:16}, month = {Nov 13}, pages = {335-339}, isbn = {0375-9601}, doi = {Doi 10.1016/0375-9601(89)90060-1}, url = {://WOS:A1989CB81600005}, author = {Anandan, J. and Pines, A.} } @article {551, title = {Nuclear Magnetic-Resonance with Dc Squid Preamplifiers}, journal = {Ieee Transactions on Magnetics}, volume = {25}, year = {1989}, note = {Ieee T MagnT6706Times Cited:21Cited References Count:23}, month = {Mar}, pages = {1193-1199}, isbn = {0018-9464}, doi = {Doi 10.1109/20.92510}, url = {://WOS:A1989T670600113}, author = {Fan, N. Q. and Heaney, M. B. and Clarke, J. and Newitt, D. and Wald, L. L. and Hahn, E. L. and Bielecki, A. and Pines, A.} } @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 {615, title = {Nmr-Studies of Clustering in Solids}, journal = {Journal of the American Chemical Society}, volume = {108}, year = {1986}, note = {J Am Chem SocF0090Times Cited:114Cited References Count:28}, month = {Nov 26}, pages = {7447-7454}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja00284a001}, url = {://WOS:A1986F009000001}, author = {Baum, J. and Pines, A.} } @article {634, title = {Nmr Imaging in Solids by Multiple-Quantum Resonance}, journal = {Journal of Magnetic Resonance}, volume = {60}, year = {1984}, note = {J Magn ResonTw096Times Cited:79Cited References Count:24}, pages = {337-341}, isbn = {1090-7807}, doi = {Doi 10.1016/0022-2364(84)90336-6}, url = {://WOS:A1984TW09600014}, author = {Garroway, A. N. and Baum, J. and Munowitz, M. G. and Pines, A.} } @article {649, title = {Nmr-Study of Molecular-Reorientation under Fivefold Symmetry - Solid Permethylferrocene}, journal = {Journal of the American Chemical Society}, volume = {103}, year = {1981}, note = {J Am Chem SocKy444Times Cited:68Cited References Count:21}, pages = {28-33}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja00391a006}, url = {://WOS:A1981KY44400006}, author = {Wemmer, D. E. and Ruben, D. J. and Pines, A.} } @article {677, title = {Nmr Double-Quantum Spin Decoupling in Solids}, journal = {Physical Review B}, volume = {18}, year = {1978}, note = {Phys Rev BFl373Times Cited:35Cited References Count:28}, pages = {112-125}, isbn = {1098-0121}, doi = {Doi 10.1103/Physrevb.18.112}, url = {://WOS:A1978FL37300014}, author = {Pines, A. and Vega, S. and Mehring, M.} } @article {686, title = {New Approach to High-Resolution Proton Nmr in Solids - Deuterium Spin Decoupling by Multiple-Quantum Transitions}, journal = {Physical Review Letters}, volume = {36}, year = {1976}, note = {Phys Rev LettBb171Times Cited:105Cited References Count:12}, pages = {110-113}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.36.110}, url = {://WOS:A1976BB17100014}, author = {Pines, A. and Ruben, D. J. and Vega, S. and Mehring, M.} } @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 {725, title = {Nuclear Magnetic Resonance Study of Dipolar Contribution to Ground State in a Series of Fulvenes}, journal = {Journal of the Chemical Society B-Physical Organic}, year = {1971}, note = {J Chem Soc BI6991Times Cited:12Cited References Count:20}, pages = {385-\&}, doi = {Doi 10.1039/J29710000385}, url = {://WOS:A1971I699100040}, author = {Pines, A. and Rabinovi.M} } @article {736, title = {A Nuclear Magnetic Resonance Total Line-Shape Treatment of Internal Rotation in Dimethylformamide}, journal = {Tetrahedron Letters}, year = {1968}, note = {Tetrahedron LettB1658Times Cited:26Cited References Count:15}, pages = {3529-\&}, isbn = {0040-4039}, url = {://WOS:A1968B165800021}, author = {Pines, A. and Rabinovi, M.} } @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} }