%0 Journal Article %J Israel Journal of Chemistry %D 2014 %T Molecular Sensing Using Hyperpolarized Xenon NMR Spectroscopy %A Palaniappan, K.K. %A Francis, M.B. %A Pines, A. %A Wemmer, D.E. %B Israel Journal of Chemistry %V 54 %P 104-112 %G eng %R 10.1002/ijch.201300128 %0 Journal Article %J Angewandte Chemie-International Edition %D 2013 %T Molecular imaging of cancer cells using a bacteriophage-based (129) xe NMR biosensor. %A Palaniappan, K. K. %A Ramirez, R.M. %A Bajaj, V.S. %A Wemmer, D.E. %A Pines, A. %A Francis, M.B. %B Angewandte Chemie-International Edition %7 2013 Mar 28 %V 52 %P 4849-4853 %G eng %N 18 %! Molecular imaging of cancer cells using a bacteriophage-based (129) xe NMR biosensor. %R 10.1002/anie.201300170 %0 Journal Article %J Applied Magnetic Resonance %D 2012 %T Measurement of Arterial Input Function in Hyperpolarized C-13 Studies %A Marjanska, M. %A Teisseyre, T. Z. %A Halpern-Manners, N. W. %A Zhang, Y. %A Iltis, I. %A Bajaj, V. %A Ugurbil, K. %A Pines, A. %A Henry, P. G. %K kinetics %X

Recently, hyperpolarized substrates generated through dynamic nuclear polarization have been introduced to study in vivo metabolism. Injection of hyperpolarized [1-C-13] pyruvate, the most widely used substrate, allows detection of time courses of [1-C-13] pyruvate and its metabolic products, such as [1-C-13] lactate and C-13-bicarbonate, in various organs. However, quantitative metabolic modeling of in vivo data to measure specific metabolic rates remains challenging without measuring the input function. In this study, we demonstrate that the input function of [1-C-13] pyruvate can be measured in vivo in the rat carotid artery using an implantable coil.

%B Applied Magnetic Resonance %V 43 %P 289-297 %8 Jul %@ 0937-9347 %G English %U ://WOS:000306421200024 %N 1-2 %M WOS:000306421200024 %! Measurement of Arterial Input Function in Hyperpolarized C-13 Studies %R Doi 10.1007/S00723-012-0348-3 %0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America %D 2010 %T Magnetic resonance imaging of oscillating electrical currents %A Halpern-Manners, N. W. %A Bajaj, V. S. %A Teisseyre, T. Z. %A Pines, A. %K nerve %X

Functional MRI has become an important tool of researchers and clinicians who seek to understand patterns of neuronal activation that accompany sensory and cognitive processes. However, the interpretation of fMRI images rests on assumptions about the relationship between neuronal firing and hemodynamic response that are not firmly grounded in rigorous theory or experimental evidence. Further, the blood-oxygen-level-dependent effect, which correlates an MRI observable to neuronal firing, evolves over a period that is 2 orders of magnitude longer than the underlying processes that are thought to cause it. Here, we instead demonstrate experiments to directly image oscillating currents by MRI. The approach rests on a resonant interaction between an applied rf field and an oscillating magnetic field in the sample and, as such, permits quantitative, frequency-selective measurements of current density without spatial or temporal cancellation. We apply this method in a current loop phantom, mapping its magnetic field and achieving a detection sensitivity near the threshold required for the detection of neuronal currents. Because the contrast mechanism is under spectroscopic control, we are able to demonstrate how ramped and phase-modulated spin-lock radiation can enhance the sensitivity and robustness of the experiment. We further demonstrate the combination of these methods with remote detection, a technique in which the encoding and detection of an MRI experiment are separated by sample flow or translation. We illustrate that remotely detected MRI permits the measurement of currents in small volumes of flowing water with high sensitivity and spatial resolution.

%B Proceedings of the National Academy of Sciences of the United States of America %V 107 %P 8519-8524 %8 May 11 %@ 0027-8424 %G English %U ://WOS:000277591200008 %N 19 %M WOS:000277591200008 %! Magnetic resonance imaging of oscillating electrical currents %R Doi 10.1073/Pnas.1003146107 %0 Journal Article %J Chemphyschem %D 2010 %T MRI Thermometry Based on Encapsulated Hyperpolarized Xenon %A Schilling, F. %A Schroder, L. %A Palaniappan, K. K. %A Zapf, S. %A Wemmer, D. E. %A Pines, A. %K xe-129 %X

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

%B Chemphyschem %V 11 %P 3529-3533 %8 Nov 15 %@ 1439-4235 %G English %U ://WOS:000285080600023 %N 16 %M WOS:000285080600023 %! MRI Thermometry Based on Encapsulated Hyperpolarized Xenon %R Doi 10.1002/Cphc.201000507 %0 Journal Article %J Review of Scientific Instruments %D 2007 %T Multipole shimming of permanent magnets using harmonic corrector rings %A Jachmann, R. C. %A Trease, D. R. %A Bouchard, L. S. %A Sakellariou, D. %A Martin, R. W. %A Schlueter, R. D. %A Budinger, T. F. %A Pines, A. %K field %X

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.

%B Review of Scientific Instruments %V 78 %8 Mar %@ 0034-6748 %G English %U ://WOS:000245320800056 %N 3 %M WOS:000245320800056 %! Multipole shimming of permanent magnets using harmonic corrector rings %R Doi 10.1063/1.2713438 %0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America %D 2006 %T Magnetic resonance imaging with an optical atomic magnetometer %A Xu, S. J. %A Yashchuk, V. V. %A Donaldson, M. H. %A Rochester, S. M. %A Budker, D. %A Pines, A. %K gas %X

We report an approach for the detection of magnetic resonance imaging without superconducting magnets and cryogenics: optical atomic magnetometry. This technique possesses a high sensitivity independent of the strength of the static magnetic field, extending the applicability of magnetic resonance imaging to low magnetic fields and eliminating imaging artifacts associated with high fields. By coupling with a remote-detection scheme, thereby improving the filling factor of the sample, we obtained time-resolved flow images of water with a temporal resolution of 0.1 s and spatial resolutions of 1.6 mm perpendicular to the flow and 4.5 mm along the flow. Potentially inexpensive, compact, and mobile, our technique provides a viable alternative for MRI detection with substantially enhanced sensitivity and time resolution for various situations where traditional MRI is not optimal.

%B Proceedings of the National Academy of Sciences of the United States of America %V 103 %P 12668-12671 %8 Aug 22 %@ 0027-8424 %G English %U ://WOS:000240035900006 %N 34 %M WOS:000240035900006 %! Magnetic resonance imaging with an optical atomic magnetometer %R Doi 10.1073/Pnas.0605396103 %0 Journal Article %J Science %D 2006 %T Molecular imaging using a targeted magnetic resonance hyperpolarized biosensor %A Schroder, L. %A Lowery, T. J. %A Hilty, C. %A Wemmer, D. E. %A Pines, A. %K agents %X

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.

%B Science %V 314 %P 446-449 %8 Oct 20 %@ 0036-8075 %G English %U ://WOS:000241382500036 %N 5798 %M WOS:000241382500036 %! Molecular imaging using a targeted magnetic resonance hyperpolarized biosensor %R Doi 10.1126/Science.1131847 %0 Journal Article %J Nature Materials %D 2006 %T Multiphase imaging of gas flow in a nanoporous material using remote-detection NMR %A Harel, E. %A Granwehr, J. %A Seeley, J. A. %A Pines, A. %K visualization %X

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.

%B Nature Materials %V 5 %P 321-327 %8 Apr %@ 1476-1122 %G English %U ://WOS:000236530400024 %N 4 %M WOS:000236530400024 %! Multiphase imaging of gas flow in a nanoporous material using remote-detection NMR %R Doi 10.1038/Nmat1598 %0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America %D 2005 %T Microfluidic gas-flow profiling using remote-detection NMR %A Hilty, C. %A McDonnell, E. E. %A Granwehr, J. %A Pierce, K. L. %A Han, S. I. %A Pines, A. %K mri %X

We have used nuclear magnetic resonance (NMR) to obtain spatially and temporally resolved profiles of gas flow in microfluidic devices. Remote detection of the NMR signal both overcomes the sensitivity limitation of NMR and enables time-of-flight measurement in addition to spatially resolved imaging. Thus, detailed insight is gained into the effects of flow, diffusion, and mixing in specific geometries. The ability for noninvasive measurement of microfluidic flow, without the introduction of foreign tracer particles, is unique to this approach and is important for the design and operation of microfluidic devices. Although here we demonstrate an application to gas flow, extension to liquids, which have higher density, is implicit.

%B Proceedings of the National Academy of Sciences of the United States of America %V 102 %P 14960-14963 %8 Oct 18 %@ 0027-8424 %G English %U ://WOS:000232811800006 %N 42 %M WOS:000232811800006 %! Microfluidic gas-flow profiling using remote-detection NMR %R Doi 10.1073/Pnas.0507566102 %0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America %D 2004 %T Microtesla MRI with a superconducting quantum interference device %A McDermott, R. %A Lee, S. K. %A ten Haken, B. %A Trabesinger, A. H. %A Pines, A. %A Clarke, J. %K system %X

MRI scanners enable fast, noninvasive, and high-resolution imaging of organs and soft tissue. The images are reconstructed from NMR signals generated by nuclear spins that precess in a static magnetic field B(0) in the presence of magnetic field gradients. Most clinical MRI scanners operate at a magnetic field B(0) = 1.5 T, corresponding to a proton resonance frequency of 64 MHz. Because these systems rely on large superconducting magnets, they are costly and demanding of infrastructure. On the other hand, low-field imagers have the potential to be less expensive, less confining, and more mobile. The major obstacle is the intrinsically low sensitivity of the low-field NMR experiment. Here, we show that prepolarization of the nuclear spins and detection with a superconducting quantum interference device (SQUID) yield a signal that is independent of B(0), allowing acquisition of high-resolution MRIs in microtesla fields. Reduction of the strength of the measurement field eliminates inhomogeneous broadening of the NMR lines, resulting in enhanced signal-to-noise ratio and spatial resolution for a fixed strength of the magnetic field gradients used to encode the image. We present high-resolution images of phantoms and other samples and T(1)-weighted contrast images acquired in highly inhomogeneous magnetic fields of 132 muT; here, T, is the spin-lattice relaxation time. These techniques could readily be adapted to existing multichannel SQUID systems used for magnetic source imaging of brain signals. Further potential applications include low-cost systems for tumor screening and imaging peripheral regions of the body.

%B Proceedings of the National Academy of Sciences of the United States of America %V 101 %P 7857-7861 %8 May 25 %@ 0027-8424 %G English %U ://WOS:000221652000005 %N 21 %M WOS:000221652000005 %! Microtesla MRI with a superconducting quantum interference device %R Doi 10.1073/Pnas.0402382101 %0 Journal Article %J Journal of Magnetic Resonance %D 2002 %T Measurement of dipolar couplings in partially oriented molecules by local field NMR spectroscopy with low-power decoupling %A Marjanska, M. %A Castiglione, F. %A Walls, J. D. %A Pines, A. %K resolution %X

Low-power phase-modulated Lee-Goldburg homonuclear decoupling was used to record PDLF spectra of fluorine-substituted benzene derivatives dissolved in nematic thermotropic liquid crystalline solvents. The low-power decoupling minimizes sample heating during RE irradiation while still achieving highly resolved PDLF spectra. The method is illustrated by recording spectra for 1,3-dichloro-4-fluoro-5-nitrobenzene, 1,3-dichloro-4-fluorobenzene, and 1, 2-difluoro benzene dissolved in different nematic solvents. (C) 2002 Elsevier Science (USA). All rights reserved.

%B Journal of Magnetic Resonance %V 158 %P 52-59 %8 Sep-Oct %@ 1090-7807 %G English %U ://WOS:000179497500006 %N 1-2 %M WOS:000179497500006 %! Measurement of dipolar couplings in partially oriented molecules by local field NMR spectroscopy with low-power decoupling %R Doi 10.1016/S1090-7807(02)00059-9 %0 Journal Article %J Journal of Physical Chemistry B %D 1998 %T Melvin P. Klein: A short personal and scientific biography %A Pines, A. %B Journal of Physical Chemistry B %V 102 %P 8123-8132 %8 Oct 15 %@ 1089-5647 %G English %U ://WOS:000076737100002 %N 42 %M WOS:000076737100002 %! Melvin P. Klein: A short personal and scientific biography %R Doi 10.1021/Jp983371z %0 Journal Article %J Solid State Nuclear Magnetic Resonance %D 1997 %T Multiple-quantum magic-angle spinning and dynamic-angle spinning NMR spectroscopy of quadrupolar nuclei %A Wang, S. H. %A Xu, Z. %A Baltisberger, J. H. %A Bull, L. M. %A Stebbins, J. F. %A Pines, A. %K rb-87 %X

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.

%B Solid State Nuclear Magnetic Resonance %V 8 %P 1-16 %8 Mar %@ 0926-2040 %G English %U ://WOS:A1997WY62900001 %N 1 %M WOS:A1997WY62900001 %! Multiple-quantum magic-angle spinning and dynamic-angle spinning NMR spectroscopy of quadrupolar nuclei %R Doi 10.1016/S0926-2040(96)01277-5 %0 Journal Article %J Journal of Physical Chemistry %D 1996 %T Measurement and assignment of long-range C-H dipolar couplings in liquid crystals by two-dimensional NMR spectroscopy %A Hong, M. %A Pines, A. %A Caldarelli, S. %K shape %X

We describe multidimensional NMR techniques to measure and assign C-13-H-1 dipolar couplings in nematic liquid crystals with high resolution. In particular, dipolar couplings between aromatic and aliphatic sites are extracted, providing valuable information on the structural correlations between these two components of thermotropic liquid crystal molecules. The NMR techniques are demonstrated on 4-pentyl-4'-biphenylcarbonitrile (5CB), a well-characterized room-temperature nematic liquid crystal. Proton-detected local-field NMR spectroscopy is employed to obtain highly resolved C-H dipolar couplings that are separated according to the chemical shifts of the carbon sites. Each C-13 cross section in the 2D spectra exhibits several doublet splittings, with the largest one resulting from the directly bonded C-H coupling, The smaller splittings originate from the long-range C-H dipolar couplings and can be assigned qualitatively by a chemical shift heteronuclear correlation (HETCOR) experiment. The HETCOR experiment incorporates a mixing period for proton spin diffusion to occur, so that maximal polarization transfer can be achieved between the unbonded C-13 and H-1 nuclei. To assign the long-range C-H couplings quantitatively, we combined these two techniques into a novel reduced-3D experiment, in which the H-1 chemical shift-displaced C-H dipolar couplings are correlated with the C-13 chemical shifts. The time domain of this experiment involves separate but synchronous incrementation of the evolution periods for the C-H dipolar couplings and the H-1 chemical shifts, with a variable ratio of the respective dwell times to optimize the resolution and facilitate resonance assignment in the spectrum.

%B Journal of Physical Chemistry %V 100 %P 14815-14822 %8 Aug 29 %@ 0022-3654 %G English %U ://WOS:A1996VE37300036 %N 35 %M WOS:A1996VE37300036 %! Measurement and assignment of long-range C-H dipolar couplings in liquid crystals by two-dimensional NMR spectroscopy %R Doi 10.1021/Jp960972m %0 Journal Article %J Journal of Physical Chemistry %D 1996 %T Measurement of carbon-proton dipolar couplings in liquid crystals by local dipolar field NMR spectroscopy %A Caldarelli, S. %A Hong, M. %A Emsley, L. %A Pines, A. %K solids %X

The performance of several different two-dimensional NMR methods for the measurement of carbon-proton dipolar couplings in liquid crystalline phases is analyzed. Proton-detected local field spectroscopy allows the measurements of short range C-H couplings, which correspond to directly bond pairs, by direct inspection of the spectra. Off magic angle (OMAS) spinning techniques can be applied to anisotropic phases that can be oriented mechanically at an angle to the magnetic field, such as nematic phases. The consequent scaling of the chemical shift anisotropy and dipolar couplings can be used to resolve otherwise overlapping resonances, Moreover, an estimate of the accuracy of the technique can be achieved by performing a series of OMAS experiments with different sample orientations.

%B Journal of Physical Chemistry %V 100 %P 18696-18701 %8 Nov 28 %@ 0022-3654 %G English %U ://WOS:A1996VV35400008 %N 48 %M WOS:A1996VV35400008 %! Measurement of carbon-proton dipolar couplings in liquid crystals by local dipolar field NMR spectroscopy %R Doi 10.1021/Jp962023z %0 Journal Article %J Synthetic Metals %D 1995 %T Magnetic-Resonance Evidence for Metallic State in Highly Conducting Polyaniline %A Sariciftci, N. S. %A Kolbert, A. C. %A Cao, Y. %A Heeger, A. J. %A Pines, A. %K polymers %X

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.

%B Synthetic Metals %V 69 %P 243-244 %8 Mar 1 %@ 0379-6779 %G English %U ://WOS:A1995QL60100097 %N 1-3 %M WOS:A1995QL60100097 %! Magnetic-Resonance Evidence for Metallic State in Highly Conducting Polyaniline %R Doi 10.1016/0379-6779(94)02435-2 %0 Journal Article %J Journal of the American Chemical Society %D 1995 %T Monitoring Xenon Clathrate Hydrate Formation on Ice Surfaces with Optically Enhanced Xe-129 Nmr %A Pietrass, T. %A Gaede, H. C. %A Bifone, A. %A Pines, A. %A Ripmeester, J. A. %K field %X

A new technique for monitoring the formation of xenon clathrate hydrates is presented. Under controlled-temperature conditions, clathrate formation is studied with optically enhanced Xe-129 NMR spectroscopy, which allows the observation of the xenon occupation of both small and large clathrate cages. The experiments were performed in a temperature range of 170 to 258 K. Only in the range of 195 to 233 K did clathrate formation occur, with applied pressures of typically 0.3 MPa. The NMR data are analyzed with a simple kinetic model, which provides a rate coefficient for clathrate formation and a time constant which describes the decay of the NMR signal intensity. The analysis of the rate coefficients and occupancy ratios of the large to the small cages under the different experimental conditions enabled us to obtain some novel information on the hydrate phase formed on ice surfaces. The results suggest that the surface phase formed initially has many more occupied small cages than the bulk phase at equilibrium and that the composition evolves toward that of the bulk phase in a few minutes. At higher temperatures (258 K) the surface phase seems to be less stable than the bulk phase.

%B Journal of the American Chemical Society %V 117 %P 7520-7525 %8 Jul 19 %@ 0002-7863 %G English %U ://WOS:A1995RK42600025 %N 28 %M WOS:A1995RK42600025 %! Monitoring Xenon Clathrate Hydrate Formation on Ice Surfaces with Optically Enhanced Xe-129 Nmr %R Doi 10.1021/Ja00133a025 %0 Journal Article %J Journal of Physical Chemistry %D 1994 %T Measurement of Internuclear Distances by Switched Angle Spinning Nmr %A Kolbert, A. C. %A Grandinetti, P. J. %A Baldwin, M. %A Prusiner, S. B. %A Pines, A. %K protein %X

Dipolar switched angle spinning, an NMR technique due to Terao et al. [Terao, T.; Miura H.; Saika, A, J. Chem. Phys. 1986, 85, 3816], has been used to measure C-13-C-13 distances in the solid state. The experiment involves rotation of the sample at two different angles during different periods of a two-dimensional experiment. An evolution period with off-magic-angle spinning and chemical shift refocusing, followed by detection of the signal under magic angle spinning, yields scaled Pake patterns in omega(1), correlated with their isotropic shifts in omega(2) allowing the high-resolution measurement of dipolar couplings. We demonstrate this experiment on samples of doubly C-13 labeled zinc acetate and a 14 amino acid peptide, in which we show that under optimal conditions distances of up to 5 Angstrom may be measured.

%B Journal of Physical Chemistry %V 98 %P 7936-7938 %8 Aug 18 %@ 0022-3654 %G English %U ://WOS:A1994PC61900003 %N 33 %M WOS:A1994PC61900003 %! Measurement of Internuclear Distances by Switched Angle Spinning Nmr %R Doi 10.1021/J100084a003 %0 Journal Article %J Physical Review A %D 1994 %T Multiple-Pulse Nuclear-Magnetic-Resonance of Optically Pumped Xenon in a Low Magnetic-Field %A Raftery, D. %A Long, H. W. %A Shykind, D. %A Grandinetti, P. J. %A Pines, A. %K ne-21 %X

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.

%B Physical Review A %V 50 %P 567-574 %8 Jul %@ 1050-2947 %G English %U ://WOS:A1994NX00100070 %N 1 %M WOS:A1994NX00100070 %! Multiple-Pulse Nuclear-Magnetic-Resonance of Optically Pumped Xenon in a Low Magnetic-Field %R Doi 10.1103/Physreva.50.567 %0 Journal Article %J Journal of Physical Chemistry %D 1992 %T Multiple-Quantum Nmr-Study of the Distribution of Benzene in Nay Zeolite %A Pearson, J. G. %A Chmelka, B. F. %A Shykind, D. N. %A Pines, A. %K solids %X

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.

%B Journal of Physical Chemistry %V 96 %P 8517-8522 %8 Oct 15 %@ 0022-3654 %G English %U ://WOS:A1992JU55500057 %N 21 %M WOS:A1992JU55500057 %! Multiple-Quantum Nmr-Study of the Distribution of Benzene in Nay Zeolite %R Doi 10.1021/J100200a057 %0 Journal Article %J Physical Review Letters %D 1991 %T Measurement of Xenon Distribution Statistics in Na-a Zeolite Cavities %A Chmelka, B. F. %A Raftery, D. %A Mccormick, A. V. %A Demenorval, L. C. %A Levine, R. D. %A Pines, A. %K fluids %X

Xe-129 NMR spectroscopy has been used to probe directly the distribution of xenon atoms confined in atomic-size Na-A zeolite cavities. For mean xenon occupancies less than about three Xe atoms per a-cage, the guest populations are well described by binomial statistics. At higher guest loadings the finite volumes of the xenon atoms become significant, as reflected by a fit of the experimental populations with a hypergeometric distribution, with a maximum of seven Xe atoms per cage. At the highest xenon loadings the experimental distribution is narrower than hypergeometric, as predicted by Monte Carlo simulations.

%B Physical Review Letters %V 66 %P 580-583 %8 Feb 4 %@ 0031-9007 %G English %U ://WOS:A1991EV89700016 %N 5 %M WOS:A1991EV89700016 %! Measurement of Xenon Distribution Statistics in Na-a Zeolite Cavities %R Doi 10.1103/Physrevlett.66.580 %0 Journal Article %J Review of Scientific Instruments %D 1990 %T Magnetic-Resonance Spectrometer with a Dc Squid Detector %A Connor, C. %A Chang, J. %A Pines, A. %B Review of Scientific Instruments %V 61 %P 1059-1063 %8 Mar %@ 0034-6748 %G English %U ://WOS:A1990CU21600021 %N 3 %M WOS:A1990CU21600021 %! Magnetic-Resonance Spectrometer with a Dc Squid Detector %R Doi 10.1063/1.1141476 %0 Journal Article %J Journal of Magnetic Resonance %D 1988 %T Multiple-Pulse Sequences for Precise Transmitter Phase Alignment %A Shaka, A. J. %A Shykind, D. N. %A Chingas, G. C. %A Pines, A. %B Journal of Magnetic Resonance %V 80 %P 96-111 %8 Oct 15 %@ 0022-2364 %G English %U ://WOS:A1988Q618700008 %N 1 %M WOS:A1988Q618700008 %! Multiple-Pulse Sequences for Precise Transmitter Phase Alignment %R Doi 10.1016/0022-2364(88)90060-1 %0 Journal Article %J Chemical Physics %D 1987 %T Multiple Quantum Nmr Excitation with a One-Quantum Hamiltonian %A Suter, D. %A Liu, S. B. %A Baum, J. %A Pines, A. %B Chemical Physics %V 114 %P 103-109 %8 May 15 %@ 0301-0104 %G English %U ://WOS:A1987H433800010 %N 1 %M WOS:A1987H433800010 %! Multiple Quantum Nmr Excitation with a One-Quantum Hamiltonian %R Doi 10.1016/0301-0104(87)80023-X %0 Journal Article %J Journal of Chemical Physics %D 1987 %T Multiple-Quantum Dynamics in Nmr - a Directed Walk through Liouville Space %A Munowitz, M. %A Pines, A. %A Mehring, M. %B Journal of Chemical Physics %V 86 %P 3172-3182 %8 Mar 15 %@ 0021-9606 %G English %U ://WOS:A1987G442400012 %N 6 %M WOS:A1987G442400012 %! Multiple-Quantum Dynamics in Nmr - a Directed Walk through Liouville Space %R Doi 10.1063/1.452028 %0 Journal Article %J Scientia Sinica Series a-Mathematical Physical Astronomical & Technical Sciences %D 1987 %T Multiple-Quantum Nmr-Study on Correlation of 2 Methyl-Groups %A Tang, J. %A Wang, J. F. %A Pines, A. %B Scientia Sinica Series a-Mathematical Physical Astronomical & Technical Sciences %V 30 %P 157-164 %8 Feb %G English %U ://WOS:A1987G805900005 %N 2 %M WOS:A1987G805900005 %! Multiple-Quantum Nmr-Study on Correlation of 2 Methyl-Groups %0 Journal Article %J Chemical Physics %D 1986 %T Multiple Quantum Spectrum of Oriented Hexane-D6 %A Drobny, G. %A Weitekamp, D. P. %A Pines, A. %B Chemical Physics %V 108 %P 179-185 %8 Oct 1 %@ 0301-0104 %G English %U ://WOS:A1986E175400001 %N 2 %M WOS:A1986E175400001 %! Multiple Quantum Spectrum of Oriented Hexane-D6 %R Doi 10.1016/0301-0104(86)85039-X %0 Journal Article %J Physical Review Letters %D 1986 %T Multiple-Quantum Nmr-Study of Clustering in Hydrogenated Amorphous-Silicon %A Baum, J. %A Gleason, K. K. %A Pines, A. %A Garroway, A. N. %A Reimer, J. A. %B Physical Review Letters %V 56 %P 1377-1380 %8 Mar 31 %@ 0031-9007 %G English %U ://WOS:A1986A628500016 %N 13 %M WOS:A1986A628500016 %! Multiple-Quantum Nmr-Study of Clustering in Hydrogenated Amorphous-Silicon %R Doi 10.1103/Physrevlett.56.1377 %0 Journal Article %J Science %D 1986 %T Multiple-Quantum Nuclear-Magnetic-Resonance Spectroscopy %A Munowitz, M. %A Pines, A. %B Science %V 233 %P 525-531 %8 Aug 1 %@ 0036-8075 %G English %U ://WOS:A1986D339100022 %N 4763 %M WOS:A1986D339100022 %! Multiple-Quantum Nuclear-Magnetic-Resonance Spectroscopy %R Doi 10.1126/Science.233.4763.525 %0 Journal Article %J Journal of Chemical Physics %D 1985 %T Multiple-Quantum Dynamics in Solid-State Nmr %A Baum, J. %A Munowitz, M. %A Garroway, A. N. %A Pines, A. %B Journal of Chemical Physics %V 83 %P 2015-2025 %@ 0021-9606 %G English %U ://WOS:A1985AQG3700002 %N 5 %M WOS:A1985AQG3700002 %! Multiple-Quantum Dynamics in Solid-State Nmr %R Doi 10.1063/1.449344 %0 Journal Article %J Molecular Physics %D 1984 %T Multiple-Quantum Nmr-Study of Molecular-Structure and Ordering in a Liquid-Crystal %A Sinton, S. W. %A Zax, D. B. %A Murdoch, J. B. %A Pines, A. %B Molecular Physics %V 53 %P 333-362 %@ 0026-8976 %G English %U ://WOS:A1984TQ35100007 %N 2 %M WOS:A1984TQ35100007 %! Multiple-Quantum Nmr-Study of Molecular-Structure and Ordering in a Liquid-Crystal %R Doi 10.1080/00268978400102351 %0 Journal Article %J Chinese Journal of Microwave and Radio Frequency Spectroscopy %D 1983 %T Multiple quantum NMR spectroscopy %A Ye, C. %A Tang, J. %A Pines, A. %B Chinese Journal of Microwave and Radio Frequency Spectroscopy %V 1 %P 12 %G eng %! Multiple quantum NMR spectroscopy %0 Journal Article %J Journal of Chemical Physics %D 1983 %T Multiple-Quantum Nmr in Solids %A Yen, Y. S. %A Pines, A. %B Journal of Chemical Physics %V 78 %P 3579-3582 %@ 0021-9606 %G English %U ://WOS:A1983QG96300031 %N 6 %M WOS:A1983QG96300031 %! Multiple-Quantum Nmr in Solids %R Doi 10.1063/1.445185 %0 Journal Article %J Journal of Chemical Physics %D 1980 %T Multiple Quantum Nmr and Relaxation of an Oriented Ch3 Group %A Tang, J. %A Pines, A. %B Journal of Chemical Physics %V 72 %P 3290-3297 %@ 0021-9606 %G English %U ://WOS:A1980JM22900051 %N 5 %M WOS:A1980JM22900051 %! Multiple Quantum Nmr and Relaxation of an Oriented Ch3 Group %R Doi 10.1063/1.439565 %0 Journal Article %J Journal of Chemical Physics %D 1980 %T Multiple Quantum Nmr-Study of Correlation of 2 Methyl-Groups %A Tang, J. %A Pines, A. %B Journal of Chemical Physics %V 73 %P 2512-2513 %@ 0021-9606 %G English %U ://WOS:A1980KH29200064 %N 5 %M WOS:A1980KH29200064 %! Multiple Quantum Nmr-Study of Correlation of 2 Methyl-Groups %R Doi 10.1063/1.440366 %0 Journal Article %J Physica B & C %D 1979 %T Multiple Quantum Coherence in Dipolar Relaxation Measurements %A Emid, S. %A Bax, A. %A Konijnendijk, J. %A Smidt, J. %A Pines, A. %B Physica B & C %V 96 %P 333-336 %@ 0378-4371 %G English %U ://WOS:A1979HB23900006 %N 3 %M WOS:A1979HB23900006 %! Multiple Quantum Coherence in Dipolar Relaxation Measurements %R Doi 10.1016/0378-4363(79)90018-4 %0 Journal Article %J Physical Review Letters %D 1974 %T Molecular Ordering and Even-Odd Effect in a Homologous Series of Nematic Liquid-Crystals %A Pines, A. %A Ruben, D. J. %A Allison, S. %B Physical Review Letters %V 33 %P 1002-1005 %@ 0031-9007 %G English %U ://WOS:A1974U373600004 %N 17 %M WOS:A1974U373600004 %! Molecular Ordering and Even-Odd Effect in a Homologous Series of Nematic Liquid-Crystals %R Doi 10.1103/Physrevlett.33.1002