@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 {3531, title = {Rotaxane probes for the detection of hydrogen peroxide by 129Xe hyperCEST NMR}, journal = {Angewandte Chemie International Edition}, year = {2019}, doi = {10.1002/anie.201903045}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/anie.201903045}, author = {Klass, Sarah H and Truxal, Ashley E and Fiala, T A and Kelly, Joseph and Nguyen, Dang and Finbloom, Joel A and Wemmer, David E and Pines, Alexander and Francis, Matthew B} } @article {3193, title = {Zero-Field Nuclear Magnetic Resonance of Chemically Exchanging Systems}, journal = {Nature Communications}, volume = {10}, year = {2019}, month = {07/2019}, abstract = {

Zero- to ultralow-field (ZULF) nuclear magnetic resonance (NMR) is an emerging tool for precision chemical analysis. In this work, we study dynamic processes and investigate the influence of chemical exchange on ZULF NMR J-spectra. We develop a computational approach that allows quantitative calculation of J-spectra in the presence of chemical exchange and apply it to study aqueous solutions of [15N]ammonium (15N) as a model system. We show that pH-dependent chemical exchange substantially affects the J-spectra and, in some cases, can lead to degradation and complete disappearance of the spectral features. To demonstrate potential applications of ZULF NMR for chemistry and biomedicine, we show a ZULF NMR spectrum of [2-13C]pyruvic acid hyperpolarized via dissolution dynamic nuclear polarization (dDNP). We foresee applications of affordable and scalable ZULF NMR coupled with hyperpolarization to study chemical exchange phenomena in vivo and in situations where high-field NMR detection is not possible to implement.

}, doi = {https://doi.org/10.1038/s41467-019-10787-9}, url = {https://www.nature.com/articles/s41467-019-10787-9?fbclid=IwAR1MB5nAamCMGynKRk0sjD6V8rTlZ329IvrVKrCwIO8QjrEH4wD23BV5gak}, author = {Danila Barskiy and Michael Tayler and Irene Marco-Rius and John Kurhanewicz and Daniel Vigneron and Sevil Cikrikci and Ayca Aydogdu and Moritz Reh and Andrey Pravdivtsev and Jan-Bernd H{\"o}vener and John Blanchard and Teng Wu and Dmitry Budker 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 {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 {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 {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 {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 {1598, title = {Gradient-free microfluidic flow labeling using thin magnetic films and remotely detected MRI (Cover Article)}, journal = {Journal of Magnetic Resonance}, volume = {249}, year = {2014}, month = {12/2014}, pages = {135-140}, author = {Halpern-Manners, N.W. and Kennedy, D.J. and Trease, D.R. and Teisseyre, T.Z. and Malecek, N.S. and Pines, A. and Bajaj, V.S.} } @article {1450, title = {Long-lived Heteronuclear Spin-Singlet States in Liquids at a Zero Magnetic Field}, journal = {Physical Review Letters}, volume = {112}, year = {2014}, pages = {077601}, chapter = {077601}, author = {Emondts, M. and Ledbetter, M. P. and Pustelny, S. and Theis, T. and Patton, B. and Blanchard, J. W. and Butler, M. C. and Budker, D. and Pines, A.} } @article {1117, title = {Chemical analysis using J-coupling multiplets in zero-field NMR}, journal = {Chemical Physics Letters}, volume = {580}, year = {2013}, month = {08/2013}, pages = {160-165}, abstract = {

Zero-field nuclear magnetic resonance (NMR) spectroscopy is emerging as a new, potentially portable, and cost-effective NMR modality with the ability to provide information-rich, high-resolution spectra. We present simple rules for analysis of zero-field NMR spectra based on first-order perturbation theory and the addition of angular momenta. These rules allow for the prediction of observed spectral lines without numerical simulation. Results are presented for a few small organic molecules with characteristic spin topologies, demonstrating unambiguous assignment of peaks, highlighting the potential of zero-field NMR as a tool for chemical identification.

}, isbn = {0009-2614}, doi = {http://dx.doi.org/10.1016/j.cplett.2013.06.042}, url = {http://www.sciencedirect.com/science/article/pii/S0009261413008191}, author = {Theis, Thomas and Blanchard, John W. and Butler, Mark C. and Ledbetter, Micah P. and Budker, Dmitry and Pines, Alexander} } @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 {247, title = {High-Resolution Zero-Field NMR J-Spectroscopy of Aromatic Compounds}, journal = {Journal of the American Chemical Society}, volume = {135}, year = {2013}, note = {J Am Chem Soc103RNTimes Cited:0Cited References Count:59}, month = {02/2013}, pages = {3607-3612}, abstract = {

We report the acquisition and interpretation of nuclear magnetic resonance (NMR) J-spectra at zero magnetic field for a series of benzene derivatives, demonstrating the analytical capabilities of zero-field NMR The zeroth-order spectral patterns do not overlap, which allows for straightforward determination of the spin interactions of substituent functional groups. Higher-order effects cause additional line splittings, revealing additional molecular information. We demonstrate resonance linewidths as narrow as 11 mHz, permitting resolution of minute frequency differences and precise determination of long-range J-couplings. The measurement of J-couplings with the high precision offered by zero-field NMR may allow further refinements in the determination of molecular structure and conformation.

}, keywords = {density}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja312239v}, url = {://WOS:000315936700050}, author = {Blanchard, J. W. and Ledbetter, M. P. and Theis, T. and Butler, M. C. and Budker, D. and Pines, A.} } @article {246, title = {Multiplets at zero magnetic field: The geometry of zero-field NMR}, journal = {The Journal of Chemical Physics}, volume = {138}, year = {2013}, month = {05/14/}, pages = {184202-15}, keywords = {Zeeman effect}, url = {http://dx.doi.org/10.1063/1.4803144}, author = {Butler, Mark C. and Ledbetter, Micah P. and Theis, Thomas and Blanchard, John W. and Budker, Dmitry and Pines, Alexander} } @article {1094, title = {Parahydrogen-induced polarization at zero magnetic field}, journal = {The Journal of Chemical Physics}, volume = {138}, year = {2013}, month = {06/2013}, pages = {234201}, abstract = {

We use symmetry arguments and simple model systems to describe the conversion of the singlet state of parahydrogen into an oscillating sample magnetization at zero magnetic field. During an initial period of free evolution governed by the scalar-coupling Hamiltonian HJ, the singlet state is converted into scalar spin order involving spins throughout the molecule. A short dc pulse along the z axis rotates the transverse spin components of nuclear species I and S through different angles, converting a portion of the scalar order into vector order. The development of vector order can be described analytically by means of single-transition operators, and it is found to be maximal when the transverse components of I are rotated by an angle of \±π/2 relative to those of S. A period of free evolution follows the pulse, during which the vector order evolves as a set of oscillating coherences. The imaginary parts of the coherences represent spin order that is not directly detectable, while the real parts can be identified with oscillations in the z component of the molecular spin dipole. The dipole oscillations are due to a periodic exchange between Iz and Sz, which have different gyromagnetic ratios. The frequency components of the resulting spectrum are imaginary, since the pulse cannot directly induce magnetization in the sample; it is only during the evolution under HJ that the vector order present at the end of the pulse evolves into detectable magnetization. \© 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4805062]

}, doi = {doi: http://dx.doi.org/10.1063/1.4805062}, url = {http://link.aip.org/link/?JCP/138/234201\&aemail=author}, author = {Butler, Mark C. and Kervern, Gwendal and Theis, Thomas and Ledbetter, Micah P. and Ganssle, Paul J. and Blanchard, John W. and Budker, Dmitry and Pines, Alexander} } @article {250, title = {Measurement of Arterial Input Function in Hyperpolarized C-13 Studies}, journal = {Applied Magnetic Resonance}, volume = {43}, year = {2012}, note = {Appl Magn Reson974GTTimes Cited:0Cited References Count:16}, month = {Jul}, pages = {289-297}, abstract = {

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.

}, keywords = {kinetics}, isbn = {0937-9347}, doi = {Doi 10.1007/S00723-012-0348-3}, url = {://WOS:000306421200024}, author = {Marjanska, M. and Teisseyre, T. Z. and Halpern-Manners, N. W. and Zhang, Y. and Iltis, I. and Bajaj, V. and Ugurbil, K. and Pines, A. and Henry, P. G.} } @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 {255, title = {Comrehensive sampling with prior information in remotely detected MRI of microfluidic devices}, journal = {Journal of Magnetic Resonance}, year = {2011}, pages = {13-20}, author = {Teisseyre, T. and Paulsen, J.L. and Bajaj, V.S. and Halpern-Manners, N. 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 {253, title = {Parahydrogen-enhanced zero-field nuclear magnetic resonance}, journal = {Nature Physics}, volume = {7}, year = {2011}, note = {Nat Phys786FYTimes Cited:9Cited References Count:31}, month = {Jul}, pages = {571-575}, abstract = {

Nuclear magnetic resonance, conventionally detected in magnetic fields of several tesla, is a powerful analytical tool for the determination of molecular identity, structure and function. With the advent of prepolarization methods and detection schemes using atomic magnetometers or superconducting quantum interference devices, interest in NMR in fields comparable to the Earth\&$\#$39;s magnetic field and below (down to zero field) has been revived. Despite the use of superconducting quantum interference devices or atomic magnetometers, low-field NMR typically suffers from low sensitivity compared with conventional high-field NMR. Here we demonstrate direct detection of zero-field NMR signals generated through parahydrogen-induced polarization, enabling high-resolution NMR without the use of any magnets. The sensitivity is sufficient to observe spectra exhibiting (13)C-(1)H scalar nuclear spin-spin couplings (known as J couplings) in compounds with (13)C in natural abundance, without the need for signal averaging. The resulting spectra show distinct features that aid chemical fingerprinting.

}, keywords = {order}, isbn = {1745-2473}, doi = {Doi 10.1038/Nphys1986}, url = {://WOS:000292290000017}, author = {Theis, T. and Ganssle, P. and Kervern, G. and Knappe, S. and Kitching, J. and Ledbetter, M. P. 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 {252, title = {Ultrafast optical encoding of magnetic resonance}, journal = {Chemical Physics Letters}, volume = {503}, year = {2011}, note = {Chem Phys Lett719FWTimes Cited:0Cited References Count:19}, month = {Feb 17}, pages = {187-190}, abstract = {

Temporal resolution in magnetic resonance imaging (MRI) is limited by the time required to encode the position of spins using time-varying (10-100 ms) magnetic field gradients. Here, we demonstrate spatial encoding of MRI images in a time that is three orders of magnitude shorter than what is possible by conventional gradient encoding techniques. Our method exploits the chemically induced dynamic nuclear polarization (CIDNP) effect and is an initial example of a set of approaches that seek to combine the favorable properties of optical spectroscopy with those of NMR for polarization, encoding, and detection. (C) 2010 Elsevier B.V. All rights reserved.

}, keywords = {state}, isbn = {0009-2614}, doi = {Doi 10.1016/J.Cplett.2010.12.063}, url = {://WOS:000287187800001}, author = {Trease, D. and Bajaj, V. S. and Paulsen, J. and Pines, A.} } @article {265, title = {Magnetic resonance imaging of oscillating electrical currents}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {107}, year = {2010}, note = {P Natl Acad Sci USA595DPTimes Cited:1Cited References Count:47}, month = {May 11}, pages = {8519-8524}, abstract = {

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.

}, keywords = {nerve}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.1003146107}, url = {://WOS:000277591200008}, author = {Halpern-Manners, N. W. and Bajaj, V. S. and Teisseyre, T. Z. and Pines, A.} } @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 {283, title = {Quantifying the diffusion of a fluid through membranes by double phase encoded remote detection magnetic resonance imaging}, journal = {Journal of Physical Chemistry B}, volume = {111}, year = {2007}, note = {J Phys Chem B240VDTimes Cited:11Cited References Count:31}, month = {Dec 20}, pages = {13929-13936}, abstract = {

We demonstrate that a position correlation magnetic resonance imaging (MRI) experiment based on two phase encoding steps separated by a delay can be used for quantifying diffusion across a membrane. This method is noninvasive, and no tracer substance or concentration gradient across the membrane is required. Because, in typical membranes, the T-1 relaxation time of the fluid spins is usually much longer than the T-2 time, we developed and implemented a new position correlation experiment based on a stimulated spin-echo, in which the relaxation attenuation of the signal is dominated by T-1 instead of T-2. This enables using relatively long delays needed in the diffusion measurements. The sensitivity of the double encoded experiment detected in a conventional way is still low because of the low filling factor of the fluid inside the NMR coil around the sample. We circumvent this problem by using the remote detection technique, which significantly increases the sensitivity, making it possible to do the measurements with gaseous fluids that have a low spin-density compared to liquids. We derive a model that enables us to extract a diffusion constant characterizing the diffusion rate through the membrane from the obtained correlation images. The double phase encoded MRI method is advantageous in any kind of diffusion studies, because the propagator of fluid molecules can directly be seen from the correlation image.

}, keywords = {mri}, isbn = {1520-6106}, doi = {Doi 10.1021/Jp076760e}, url = {://WOS:000251615400011}, author = {Telkki, V. V. and Hilty, C. and Garcia, S. and Harel, E. 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 {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 {314, title = {SQUID-detected MRI at 132 mu T with T(1)-weighted contrast established at 10 mu T-300 mT}, journal = {Magnetic Resonance in Medicine}, volume = {53}, year = {2005}, note = {Magn Reson Med888NETimes Cited:73Cited References Count:20}, month = {Jan}, pages = {9-14}, abstract = {

T(1)-weighted contrast MRI with prepolarization was detected with a superconducting quantum interference device (SQUID). A spin evolution period in a variable field between prepolarization and detection enabled the measurement of T(1) in fields between 1.7 muT and 300 mT; T, dispersion curves of agarose gel samples over five decades in frequency were obtained. SQUID detection at 5.6 kHz drastically reduces the field homogeneity requirements compared to conventional field-cycling methods using Faraday coil detection. This allows T(1) dispersion measurements to be easily combined with MRI, so that T(1) in a wide range of fields can be used for tissue contrast. Images of gel phantoms with T(1)-weighted contrast at four different fields between 10 muT and 300 mT demonstrated dramatic contrast enhancement in low fields. A modified inversion recovery technique further enhanced the contrast by selectively suppressing the signal contribution for a specific value of the low-field T(1). Published 2004 Wiley-Liss, Inc.

}, keywords = {dispersion}, isbn = {0740-3194}, doi = {Doi 10.1002/Mrm.20316}, url = {://WOS:000226380700003}, author = {Lee, S. K. and Mossle, M. and Myers, W. and Kelso, N. and Trabesinger, A. H. and Pines, A. and Clarke, J.} } @article {320, title = {Xenon NMR as a probe for microporous and mesoporous solids, polymers, liquid crystals, solutions, flames, proteins, imaging}, journal = {Actualite Chimique}, year = {2005}, note = {Actual ChimiqueSuppl. 287952GHTimes Cited:3Cited References Count:89}, month = {Jun}, pages = {16-34}, abstract = {

We present in this paper some examples of the applications of the Nuclear Magnetic Resonance (NMR) of xenon used as a probe in the study of different chemical environments: determination of the porosity of micro-and mesoporous solids, evaluation of the concentrations and sizes of amorphous domains in solid polymers, characterization of liquid crystals, study of combustion processes at high temperature, determination of the structure and dynamics of organic systems and proteins in solution, assessment of cerebral blood flow.

}, keywords = {silica-gels}, isbn = {0151-9093}, url = {://WOS:000230991500005}, author = {Bartik, K. and Choquet, P. and Constantinesco, A. and Duhamel, G. and Fraissard, J. and Hyacinthe, J. N. and Jokisaari, J. and Locci, E. and Lowery, T. J. and Luhmer, M. and Meersmann, T. and Moudrakovski, I. L. and Pavlovskaya, G. E. and Pierce, K. L. and Pines, A. and Ripmeester, J. A. and Telkki, V. V. and Veeman, W. S.} } @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 {321, title = {Hyperpolarized xenon nuclear spins detected by optical atomic magnetometry}, journal = {Physical Review Letters}, volume = {93}, year = {2004}, note = {Phys Rev Lett863ATTimes Cited:32Cited References Count:22}, month = {Oct 15}, abstract = {

We report the use of an atomic magnetometer based on nonlinear magneto-optical rotation with frequency-modulated light to detect nuclear magnetization of xenon gas. The magnetization of a spin-exchange-polarized xenon sample (1.7 cm(3) at a pressure of 5 bars, natural isotopic abundance, polarization 1\%), prepared remotely to the detection apparatus, is measured with an atomic sensor. An average magnetic field of similar to10 nG induced by the xenon sample on the 10 cm diameter atomic sensor is detected with signal-to-noise ratio similar to10, limited by residual noise in the magnetic environment. The possibility of using modern atomic magnetometers as detectors of nuclear magnetic resonance and in magnetic resonance imaging is discussed. Atomic magnetometers appear to be ideally suited for emerging low-field and remote-detection magnetic resonance applications.

}, keywords = {mri}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.93.160801}, url = {://WOS:000224533300012}, author = {Yashchuk, V. V. and Granwehr, J. and Kimball, D. F. and Rochester, S. M. and Trabesinger, A. H. and Urban, J. T. and Budker, D. and Pines, A.} } @article {331, title = {Microtesla MRI with a superconducting quantum interference device}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {101}, year = {2004}, note = {P Natl Acad Sci USA823ZCTimes Cited:76Cited References Count:29}, month = {May 25}, pages = {7857-7861}, abstract = {

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.

}, keywords = {system}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0402382101}, url = {://WOS:000221652000005}, author = {McDermott, R. and Lee, S. K. and ten Haken, B. and Trabesinger, A. H. and Pines, A. and Clarke, J.} } @article {323, title = {Self-diffusion measurements with chemical shift resolution in inhomogeneous magnetic fields}, journal = {Journal of Magnetic Resonance}, volume = {168}, year = {2004}, note = {J Magn Reson814XETimes Cited:5Cited References Count:27}, month = {May}, pages = {31-35}, abstract = {

A methodology for chemical shift resolved molecular self-diffusion measurements in time-independent static and radiofrequency field gradients is demonstrated. Diffusion encoding is provided by a stimulated echo Sequence with additional z-storage that allows for a change of diffusion time Without affecting the relaxation weighting. The signal is acquired stroboscopically between the pulses of a train of adiabatic double passages that induces a z-rotation Counteracting the phase spread resulting from precession in the inhomogeneous static field. as demonstrated in recent approaches to the goal of high-resolution \"ex situ\" NMR. Simulations of the pulse sequence show that the acquired signal results from the desired coherence pathway. Successful demonstrations of the experiment were performed on a Mixture of water and isopropanol. Published by Elsevier Inc.

}, keywords = {excitation}, isbn = {1090-7807}, doi = {Doi 10.1016/J.Jmr.2004.01.018}, url = {://WOS:000221006600004}, author = {Topgaard, D. 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 {322, title = {SQUID-detected liquid state NMR in microtesla fields}, journal = {Journal of Physical Chemistry A}, volume = {108}, year = {2004}, note = {J Phys Chem A772FTTimes Cited:32Cited References Count:36}, month = {Feb 12}, pages = {957-963}, abstract = {

Nuclear magnetic resonance (NMR) experiments performed in magnetic fields on the order of microtesla yield line widths comparable to the lifetime limit even in grossly inhomogeneous magnets. The potential loss in sensitivity is overcome by combining prepolarization in fields on the order of millitesla and signal detection with a Superconducting Quantum Interference Device (SQUID). The enhanced spectral resolution attainable in microtesla fields enables NMR studies of pure liquids and solutions without the need for strong magnets. We have investigated a variety of heteronuclear systems in both the weak and strong J-coupling regimes. Six different nuclear species have been detected with the same experimental apparatus. NMR signals of thermally polarized protons were obtained in fields as low as 554 nT.

}, keywords = {water}, isbn = {1089-5639}, doi = {Doi 10.1021/Jp035181g}, url = {://WOS:000188831500005}, author = {Trabesinger, A. H. and McDermott, R. and Lee, S. K. and M{\"u}ck, M. and Clarke, J. 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 {357, title = {Liquid-state NMR and scalar couplings in microtesla magnetic fields}, journal = {Science}, volume = {295}, year = {2002}, note = {Science534ADTimes Cited:140Cited References Count:20}, month = {Mar 22}, pages = {2247-2249}, abstract = {

We obtained nuclear magnetic resonance (NMR) spectra of liquids in fields of a few microtesla, using prepolarization in fields of a few millitesta and detection with a dc superconducting quantum interference device (SQUID). Because the sensitivity of the SQUID is frequency independent, we enhanced both signal-to-noise ratio and spectral resolution by detecting the NMR signal in extremely tow magnetic fields, where the NMR tines become very narrow even for grossly inhomogeneous measurement fields. In the absence of chemical shifts, proton-phosphorous scalar (J) couplings have been detected, indicating the presence of specific covalent bonds. This observation opens the possibility for \"pure J spectroscopy\" as a diagnostic tool, for the detection of molecules in low magnetic fields.

}, keywords = {resonance}, isbn = {0036-8075}, doi = {Doi 10.1126/Science.1069280}, url = {://WOS:000174561700039}, author = {McDermott, R. and Trabesinger, A. H. and M{\"u}ck, M. and Hahn, E. L. and Pines, A. and Clarke, J.} } @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 {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 {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 {400, title = {In situ NMR analysis of fluids contained in sedimentary rock}, journal = {Journal of Magnetic Resonance}, volume = {133}, year = {1998}, note = {J Magn Reson116WNTimes Cited:23Cited References Count:23}, month = {Aug}, pages = {385-387}, abstract = {

Limitations of resolution and absorption in standard chemical spectroscopic techniques have made it difficult to study fluids in sedimentary rocks. In this paper, we show that a chemical characterization of pore fluids may be obtained in situ by magic angle spinning (MAS) nuclear magnetic resonance (NMR), which is normally used for solid samples. H-1 MAS-NMR spectra of water and crude oil in Berea sandstone show sufficient chemical shift resolution for a straightforward determination of the oil/water ratio, (C) 1998 Academic Press.

}, keywords = {oil}, isbn = {1090-7807}, doi = {Doi 10.1006/Jmre.1998.1459}, url = {://WOS:000075748200020}, author = {de Swiet, T. M. and Tomaselli, M. and Hurlimann, M. D. and Pines, A.} } @article {405, title = {Low field magnetic resonance images of polarized noble gases obtained with a dc superconducting quantum interference device}, journal = {Applied Physics Letters}, volume = {72}, year = {1998}, note = {Appl Phys LettZg930Times Cited:37Cited References Count:24}, month = {Apr 13}, pages = {1908-1910}, abstract = {

Using a low transition temperature superconducting quantum interference device as a detector, we have obtained magnetic resonance images of laser-polarized He-3 gas and solid Xe-129 at 4.2 K in magnetic fields as low as 0.54 mT (He-3) and 1 mT (Xe-129), corresponding to Larmor frequencies of 17.6 and 11.8 kHz, respectively. The experimental resolution of the images is similar to 500 mu m for He-3 ill the gas phase and similar to 950 mu m for Xe-129 in the solid state. (C) 1998 American Institute of Physics.

}, keywords = {mri}, isbn = {0003-6951}, doi = {Doi 10.1063/1.121223}, url = {://WOS:000073054300038}, author = {Augustine, M. P. and Wong-Foy, A. and Yarger, J. L. and Tomaselli, M. and Pines, A. and TonThat, D. M. and Clarke, J.} } @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 {401, title = {Reversal of radio-frequency-driven spin diffusion by reorientation of the sample spinning axis}, journal = {Journal of Chemical Physics}, volume = {108}, year = {1998}, note = {J Chem PhysYr359Times Cited:9Cited References Count:39}, month = {Jan 15}, pages = {826-829}, abstract = {

The dipolar Hamiltonian in a rapidly rotating sample is scaled by the second Legendre polynomial of the cosine of the angle between the rotation axis and the static magnetic field. It is, therefore, possible to refocus the spatial polarization-transfer process, often termed spin diffusion, in extended spin systems by reorienting the rotor axis such that the dipolar interaction Hamiltonian changes sign. We present experimental results which demonstrate that a rapid mechanical sample reorientation leads to a time reversal of the \"radio-frequency-driven\" spin diffusion among C-13 spins. (C) 1998 American Institute of Physics. [S0021-9606(98)03503-X].

}, keywords = {echoes}, isbn = {0021-9606}, doi = {Doi 10.1063/1.475494}, url = {://WOS:000071487500002}, author = {De Paul, S. M. and Tomaselli, M. and Pines, A. and Ernst, M. and Meier, B. H.} } @article {391, title = {Scalar and anisotropic J interactions in undoped InP: A triple-resonance NMR study}, journal = {Physical Review B}, volume = {58}, year = {1998}, note = {Phys Rev B125HUTimes Cited:29Cited References Count:40}, month = {Oct 1}, pages = {8627-8633}, abstract = {

The heteronuclear J-coupling tensor between nearest neighbor P-31 and In-113 spins in undoped InP is investigated by means of In-113--\>P-31 polarization transfer under rapid magic angle spinning (MAS). The scalar contribution can be measured directly and is found to have the value \J(iso)(P-31-In-113,In-115)\ = (225+/-10) Hz. The principal value of the traceless anisotropic J-coupling tensor (pseudodipolar coupling) is determined to be J(aniso)(P-31-In-113,In-115)= 2/3[J(parallel to)(P-31-In-113,In-115)-J(perpendicular to)(P-31-In-113,In-115)] = (813+/-50) or (1733+/-50) Hz, assuming axial symmetry with the principal axis parallel to the In-P bond. Our values deviate from those reported previously [M. Engelsberg and R. E. Norberg, Phys. Rev. B 5, 3395 (1972)] [based on a moment analysis of the P-31 resonance \J(iso)(31P-In-113,In-115)\ = 350 Hz and J(aniso)(P-31-In-113,In-115) = 1273 Hz], but confirm the postulate that the nearest neighbor P-31-In-113,In-115 magnetic dipolar and pseudodipolar interactions are of the same order of magnitude and partially cancel each other.

}, keywords = {solids}, isbn = {0163-1829}, doi = {Doi 10.1103/Physrevb.58.8627}, url = {://WOS:000076232100075}, author = {Tomaselli, M. and deGraw, D. and Yarger, J. L. and Augustine, M. P. and Pines, A.} } @article {398, title = {Time reversal of cross-polarization in solid-state NMR}, journal = {Molecular Physics}, volume = {95}, year = {1998}, note = {Mol Phys146XYTimes Cited:4Cited References Count:21}, month = {Dec 10}, pages = {849-858}, abstract = {

Cross-polarization at the Hartmann-Hahn condition in solid-state NMR frequently is described in terms of thermodynamics. Spin temperatures characterizing the canonical density operator are assigned to the Zeeman reservoirs of the two spins and the cross-polarization process brings about a state of equilibrium of the two reservoirs with a common temperature. In such a model, cross-polarization from an initially polarized spin species (I spins) to another spin species (S spins) is inherently an irreversible process accompanied by an increase in the entropy of the system. However, a cross-polarization echo can be generated whereby the polarization transferred to the S spins returns to the I spins, restoring the initial density operator. Therefore a thermodynamic description should be applied with care even in samples where the build-up and the decay of the magnetization can be approximated well by multiexponential processes. Such cross-polarization echoes are formed by the consecutive application of two pulse trains that produce effective Hamiltonians differing in sign. The \&$\#$39;time reversal\&$\#$39; of cross-polarization is consistent with both the increase in Zeeman entropy during the approach to equilibrium and with the constraint of unitary quantum evolution.

}, keywords = {echoes}, isbn = {0026-8976}, doi = {Doi 10.1080/002689798166477}, url = {://WOS:000077460200014}, author = {Ernst, M. and Meier, B. H. and Tomaselli, M. and Pines, A.} } @article {397, title = {Time-reversal of cross-polarization in nuclear magnetic resonance}, journal = {Journal of Chemical Physics}, volume = {108}, year = {1998}, note = {J Chem Phys108FUTimes Cited:11Cited References Count:17}, month = {Jun 15}, pages = {9611-9613}, abstract = {

It is demonstrated that the time evolution of the heteronuclear polarization-transfer process in a dipolar-coupled nuclear spin system can be reversed, leading to the observation of cross polarization echoes. The cross-polarization echoes are induced by consecutive application of two pulse trains that produce effective Hamiltonians that differ only in sign, Cross-polarization echoes have been recorded for a powder sample of alanine. The time evolution of the spin;system is consistent with both unitary quantum dynamics and with spin thermodynamics of two systems approaching a common spin temperature. (C) 1998 American Institute of Physics.

}, keywords = {echoes}, isbn = {0021-9606}, doi = {Doi 10.1063/1.476435}, url = {://WOS:000075256100001}, author = {Ernst, M. and Meier, B. H. and Tomaselli, M. and Pines, A.} } @article {418, title = {Determination of dihedral angles in peptides through experimental and theoretical studies of alpha-carbon chemical shielding tensors}, journal = {Journal of the American Chemical Society}, volume = {119}, year = {1997}, note = {J Am Chem SocXt037Times Cited:90Cited References Count:57}, month = {Aug 20}, pages = {7827-7831}, abstract = {

A simple method for the determination of backbone dihedral angles in peptides and proteins is presented. The chemical-shift anisotropies (CSA) of the central alanine alpha-carbon in powdered crystalline tripeptides, whose structures have been determined previously by X-ray crystallography, were measured by cross-polarization magic-angle-spinning nuclear magnetic resonance. The experimental CSA values were correlated with ab initio chemical-shielding calculations over Ramanchandran phi/psi space on an N-formyl-L-alanine amide fragment. Using this correlation, phi/psi probability surfaces for one of the tripeptides were calculated based only on the alpha-carbon CSA, allowing a prediction of backbone angles. Dihedral angles predicted by these calculations fall within +/-12 degrees of the values determined by crystallography. This approach should be useful in the determination of solid-slate protein structure.

}, keywords = {crystal-structure}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja970124k}, url = {://WOS:A1997XT03700025}, author = {Heller, J. and Laws, D. D. and Tomaselli, M. and King, D. S. and Wemmer, D. E. and Pines, A. and Havlin, R. H. and Oldfield, E.} } @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 {408, title = {Low magnetic field dynamic nuclear polarization using a single-coil two-channel probe}, journal = {Review of Scientific Instruments}, volume = {68}, year = {1997}, note = {Rev Sci InstrumWp247Times Cited:4Cited References Count:29}, month = {Mar}, pages = {1527-1531}, abstract = {

We describe the design and construction of a single-coil, two-channel probe for the detection of low-field magnetic resonance using dynamic nuclear polarization (DNP). The high-frequency channel of the probe, which is used to saturate the electron spins, is tuned to the electron Larmor frequency, 75 MHz at 2.7 mT, and matched to 50 Omega. Low-field, H-1 nuclear magnetic resonance (NMR) is detected through the second, low-frequency channel at frequencies \<1 MHz. The performance of the probe was tested by measuring the DNP of protons in a manganese (II) chloride solution at 2.7 mT. At the proton NMR frequency of 120 kHz, the signal amplitude was enhanced over the value without DNP by a factor of about 200. (C) 1997 American Institute of Physics.

}, keywords = {nmr}, isbn = {0034-6748}, doi = {Doi 10.1063/1.1147641}, url = {://WOS:A1997WP24700033}, author = {TonThat, D. M. and Augustine, M. P. and Pines, A. and Clarke, J.} } @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 {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 {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 {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 {438, title = {Xe-129 Nmr-Studies of Hyper-Cross-Linked Polyarylcarbinols - Rigid Versus Flexible Structures}, journal = {Chemistry of Materials}, volume = {7}, year = {1995}, note = {Chem MaterRk993Times Cited:27Cited References Count:30}, month = {Jul}, pages = {1325-1332}, abstract = {

Xenon NMR is used with adsorption measurements to infer information about the microstructure of some novel hyper-cross-linked polyarylcarbinols. It is shown that rigidrod connecting units are necessary for microporosity in these systems, as hyper-cross-linked polymers based on flexible structures are found to have conventional surface areas and xenon NMR spectra. A microporous polymer based on rigid triarylcarbinol monomers shows high xenon uptake and a linear chemical shift variation with pressure at room temperature. Spin-lattice relaxation and cross-polarization dynamics are studied at low temperatures. In this regime the xenon has extremely long equilibration times, and the adsorption dynamics are complicated but give important insight into the polymer topology. The data are compared with two possible models of the polymer microstructwre.

}, keywords = {adsorption}, isbn = {0897-4756}, doi = {Doi 10.1021/Cm00055a008}, url = {://WOS:A1995RK99300008}, author = {Urban, C. and Mccord, E. F. and Webster, O. W. and Abrams, L. and Long, H. W. and Gaede, H. and Tang, P. 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 {474, title = {Spin-Polarized Xe-129 Nmr-Study of a Polymer Surface}, journal = {Journal of Physical Chemistry}, volume = {97}, year = {1993}, note = {J Phys Chem-UsKp603Times Cited:51Cited References Count:48}, month = {Feb 25}, pages = {1649-1655}, abstract = {

A method for NMR studies of low surface area materials using optically pumped xenon gas is described. The method has been used to investigate spin-polarized xenon adsorbed onto poly(acrylic acid). The temperature dependence of the xenon-surface interaction, as measured by the xenon chemical shifts extrapolated to zero pressure, is shown to be consistent with a simple model of chemical exchange between the gas and adsorbed phases. The magnitude of the surface contribution to the Xe-129 chemical shift indicates a relatively strong interaction between xenon and poly(acrylic acid), possibly due to the polar carboxylic acid functional groups at the polymer surface. From the pressure dependence of the Xe-129 shift, the diffusion coefficient of xenon on poly(acrylic acid) is estimated to be 3.3 x 10(-5) cm2/s.

}, keywords = {temperature}, isbn = {0022-3654}, doi = {Doi 10.1021/J100110a029}, url = {://WOS:A1993KP60300029}, author = {Raftery, D. and Reven, L. and Long, H. and Pines, A. and Tang, P. and Reimer, J. 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 {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 {523, title = {Investigations of Adsorbed Organic-Molecules in Na-Y Zeolite by Xe-129 Nmr}, journal = {Journal of Physical Chemistry}, volume = {94}, year = {1990}, note = {J Phys Chem-UsCh532Times Cited:61Cited References Count:26}, month = {Jan 11}, pages = {27-31}, isbn = {0022-3654}, doi = {Doi 10.1021/J100364a006}, url = {://WOS:A1990CH53200006}, author = {Demenorval, L. C. and Raftery, D. and Liu, S. B. and Takegoshi, K. and Ryoo, R. and Pines, A.} } @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 {583, title = {Distribution of Hexamethylbenzene in a Zeolite Studied by Xe-129 and Multiple-Quantum Nmr}, journal = {Journal of Physical Chemistry}, volume = {91}, year = {1987}, note = {J Phys Chem-UsL6632Times Cited:63Cited References Count:16}, month = {Dec 31}, pages = {6575-6577}, isbn = {0022-3654}, doi = {Doi 10.1021/J100311a003}, url = {://WOS:A1987L663200003}, author = {Ryoo, R. and Liu, S. B. and Demenorval, L. C. and Takegoshi, K. and Chmelka, B. and Trecoske, M. and Pines, A.} } @article {591, title = {Effect of Correlated Proton Jumps on the Zero-Field Nmr-Spectrum of Solid P-Toluic Acid}, journal = {Journal of Physical Chemistry}, volume = {91}, year = {1987}, note = {J Phys Chem-UsH0705Times Cited:15Cited References Count:14}, month = {Apr 23}, pages = {2240-2242}, isbn = {0022-3654}, doi = {Doi 10.1021/J100293a006}, url = {://WOS:A1987H070500006}, author = {Jarvie, T. P. and Thayer, A. M. and Millar, J. M. and Pines, A.} } @article {573, title = {Heteronuclear Zero-Field Nmr of Liquid-Crystals}, journal = {Journal of Magnetic Resonance}, volume = {72}, year = {1987}, note = {J Magn ResonH2852Times Cited:1Cited References Count:13}, month = {May}, pages = {567-573}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(87)90164-8}, url = {://WOS:A1987H285200020}, author = {Thayer, A. M. and Luzar, M. and Pines, A.} } @article {574, title = {Multiple-Quantum Nmr-Study on Correlation of 2 Methyl-Groups}, journal = {Scientia Sinica Series a-Mathematical Physical Astronomical \& Technical Sciences}, volume = {30}, year = {1987}, note = {Sci China Ser AG8059Times Cited:2Cited References Count:12}, month = {Feb}, pages = {157-164}, url = {://WOS:A1987G805900005}, author = {Tang, J. and Wang, J. F. and Pines, A.} } @article {587, title = {Quenching of Residual Fields by Nonaxially Symmetrical Dipolar Coupling in Zero-Field Nmr}, journal = {Journal of Magnetic Resonance}, volume = {73}, year = {1987}, note = {J Magn ResonJ1554Times Cited:1Cited References Count:22}, month = {Jul}, pages = {459-466}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(87)90008-4}, url = {://WOS:A1987J155400008}, author = {Luzar, M. and Thayer, A. M. and Pines, A.} } @article {586, title = {Theory of Line-Shapes for Zero-Field Nmr in the Presence of Molecular-Motion}, journal = {Journal of Chemical Physics}, volume = {87}, year = {1987}, note = {J Chem PhysL1661Times Cited:10Cited References Count:41}, month = {Dec 15}, pages = {6867-6876}, isbn = {0021-9606}, doi = {Doi 10.1063/1.453381}, url = {://WOS:A1987L166100011}, author = {Meier, P. and Kothe, G. and Jonsen, P. and Trecoske, M. and Pines, A.} } @article {570, title = {Zero-Field Nmr}, journal = {Accounts of Chemical Research}, volume = {20}, year = {1987}, note = {Accounts Chem ResG2724Times Cited:35Cited References Count:39}, month = {Feb}, pages = {47-53}, isbn = {0001-4842}, doi = {Doi 10.1021/Ar00134a001}, url = {://WOS:A1987G272400001}, author = {Thayer, A. M. and Pines, A.} } @article {572, title = {Zero-Field Nmr of Nematic Liquid-Crystals with Positive and Negative Magnetic-Susceptibility Anisotropies}, journal = {Journal of Physical Chemistry}, volume = {91}, year = {1987}, note = {J Phys Chem-UsG8355Times Cited:4Cited References Count:22}, month = {Apr 9}, pages = {2194-2197}, isbn = {0022-3654}, doi = {Doi 10.1021/J100292a043}, url = {://WOS:A1987G835500043}, author = {Thayer, A. M. and Luzar, M. and Pines, A.} } @article {588, title = {Zero-Field Nmr of Uniaxial and Biaxial Smectic Liquid-Crystals}, journal = {Molecular Physics}, volume = {62}, year = {1987}, note = {Mol PhysL0770Times Cited:2Cited References Count:30}, month = {Oct 20}, pages = {573-583}, isbn = {0026-8976}, doi = {Doi 10.1080/00268978700102411}, url = {://WOS:A1987L077000003}, author = {Luzar, M. and Thayer, A. M. and Pines, A.} } @article {571, title = {Zero-Field Nmr-Study of the Biaxial Smectic-E Phase}, journal = {Liquid Crystals}, volume = {2}, year = {1987}, note = {Liq CrystH5818Times Cited:3Cited References Count:12}, month = {Mar-Apr}, pages = {241-244}, isbn = {0267-8292}, doi = {Doi 10.1080/02678298708086296}, url = {://WOS:A1987H581800012}, author = {Thayer, A. M. and Luzar, M. and Pines, A.} } @article {598, title = {Composite Pulses in Zero-Field Nmr}, journal = {Journal of Magnetic Resonance}, volume = {70}, year = {1986}, note = {J Magn ResonF4381Times Cited:8Cited References Count:33}, month = {Dec}, pages = {518-522}, isbn = {0022-2364}, doi = {Doi 10.1016/0022-2364(86)90147-2}, url = {://WOS:A1986F438100023}, author = {Thayer, A. M. and Pines, A.} } @article {606, title = {High-Resolution Studies of Deuterium by Time-Domain Zero-Field Nqr}, journal = {Journal of Magnetic Resonance}, volume = {69}, year = {1986}, note = {J Magn ResonE1115Times Cited:11Cited References Count:49}, month = {Sep}, pages = {243-257}, isbn = {1090-7807}, doi = {Doi 10.1016/0022-2364(86)90076-4}, url = {://WOS:A1986E111500005}, author = {Millar, J. M. and Thayer, A. M. and Zimmermann, H. and Pines, A.} } @article {611, title = {Iterative Maps for Bistable Excitation of 2-Level Systems}, journal = {Physical Review Letters}, volume = {56}, year = {1986}, note = {Phys Rev LettC1114Times Cited:23Cited References Count:21}, month = {May 5}, pages = {1905-1908}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.56.1905}, url = {://WOS:A1986C111400006}, author = {Cho, H. M. and Tycko, R. and Pines, A. and Guckenheimer, J.} } @article {614, title = {Spatially Selective Nmr with Broad-Band Radiofrequency Pulses}, journal = {Chemical Physics}, volume = {105}, year = {1986}, note = {Chem PhysC7043Times Cited:6Cited References Count:47}, month = {Jun 1}, pages = {7-14}, isbn = {0301-0104}, doi = {Doi 10.1016/0301-0104(86)80051-9}, url = {://WOS:A1986C704300002}, author = {Baum, J. and Tycko, R. and Pines, A.} } @article {613, title = {Time Domain Zero-Field Nmr and Nqr}, journal = {Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences}, volume = {41}, year = {1986}, note = {Z Naturforsch AA6350Times Cited:2Cited References Count:22}, month = {Jan-Feb}, pages = {440-444}, isbn = {0932-0784}, url = {://WOS:A1986A635000084}, author = {Bielecki, A. and Zax, D. B. and Thayer, A. M. and Millar, J. M. and Pines, A.} } @article {599, title = {Two-Dimensional Zero-Field Nmr and Nqr}, journal = {Chemical Physics Letters}, volume = {129}, year = {1986}, note = {Chem Phys LettD7200Times Cited:16Cited References Count:24}, month = {Aug 15}, pages = {55-58}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(86)80167-1}, url = {://WOS:A1986D720000011}, author = {Thayer, A. M. and Millar, J. M. and Pines, A.} } @article {607, title = {Zero-Field Nmr of Small-Amplitude Motions in a Polycrystalline Solid}, journal = {Journal of the American Chemical Society}, volume = {108}, year = {1986}, note = {J Am Chem SocD7238Times Cited:22Cited References Count:21}, month = {Aug 20}, pages = {5113-5116}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja00277a012}, url = {://WOS:A1986D723800012}, author = {Millar, J. M. and Thayer, A. M. and Zax, D. B. and Pines, A.} } @article {600, title = {Zero-Field Nuclear-Magnetic-Resonance of a Nematic Liquid-Crystal}, journal = {Journal of Physical Chemistry}, volume = {90}, year = {1986}, note = {J Phys Chem-UsA8609Times Cited:10Cited References Count:32}, month = {Apr 10}, pages = {1577-1581}, isbn = {0022-3654}, doi = {Doi 10.1021/J100399a024}, url = {://WOS:A1986A860900024}, author = {Thayer, A. M. and Millar, J. M. and Luzar, M. and Jarvie, T. P. and Pines, A.} } @article {624, title = {Broad-Band and Adiabatic Inversion of a 2-Level System by Phase-Modulated Pulses}, journal = {Physical Review A}, volume = {32}, year = {1985}, note = {Phys Rev AAvc77Times Cited:227Cited References Count:35}, pages = {3435-3447}, isbn = {1050-2947}, doi = {Doi 10.1103/Physreva.32.3435}, url = {://WOS:A1985AVC7700029}, author = {Baum, J. and Tycko, R. and Pines, A.} } @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 {618, title = {Fixed-Point Theory of Iterative Excitation Schemes in Nmr}, journal = {Journal of Chemical Physics}, volume = {83}, year = {1985}, note = {J Chem PhysAqw58Times Cited:126Cited References Count:72}, pages = {2775-2802}, isbn = {0021-9606}, doi = {Doi 10.1063/1.449228}, url = {://WOS:A1985AQW5800020}, author = {Tycko, R. and Pines, A. and Guckenheimer, J.} } @article {621, title = {Zero-Field Nmr and Nqr with Selective Pulses and Indirect Detection}, journal = {Journal of Chemical Physics}, volume = {83}, year = {1985}, note = {J Chem PhysAmg31Times Cited:36Cited References Count:31}, pages = {934-938}, isbn = {0021-9606}, doi = {Doi 10.1063/1.449419}, url = {://WOS:A1985AMG3100004}, author = {Millar, J. M. and Thayer, A. M. and Bielecki, A. and Zax, D. B. 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 {631, title = {Iterative Schemes for Broad-Band and Narrow-Band Population-Inversion in Nmr}, journal = {Chemical Physics Letters}, volume = {111}, year = {1984}, note = {Chem Phys LettTu813Times Cited:50Cited References Count:18}, pages = {462-467}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(84)85541-4}, url = {://WOS:A1984TU81300031}, author = {Tycko, R. and Pines, A.} } @article {630, title = {Spatial Localization of Nmr Signals by Narrowband Inversion}, journal = {Journal of Magnetic Resonance}, volume = {60}, year = {1984}, note = {J Magn ResonTs255Times Cited:66Cited References Count:26}, pages = {156-160}, isbn = {1090-7807}, doi = {Doi 10.1016/0022-2364(84)90042-8}, url = {://WOS:A1984TS25500022}, author = {Tycko, R. and Pines, A.} } @article {643, title = {Broad-Band Population-Inversion by Phase Modulated Pulses}, journal = {Journal of Chemical Physics}, volume = {79}, year = {1983}, note = {J Chem PhysRn512Times Cited:89Cited References Count:13}, pages = {4643-4644}, isbn = {0021-9606}, doi = {Doi 10.1063/1.446381}, url = {://WOS:A1983RN51200071}, author = {Baum, J. and Tycko, R. and Pines, A.} } @article {638, title = {Multiple quantum NMR spectroscopy}, journal = {Chinese Journal of Microwave and Radio Frequency Spectroscopy}, volume = {1}, year = {1983}, pages = {12}, author = {Ye, C. and Tang, J. and Pines, A.} } @article {642, title = {Spin Diffusion between Inequivalent Quadrupolar Nuclei by Double-Quantum Flip-Flops}, journal = {Chemical Physics Letters}, volume = {99}, year = {1983}, note = {Chem Phys LettRb604Times Cited:13Cited References Count:13}, pages = {35-40}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(83)80265-6}, url = {://WOS:A1983RB60400008}, author = {Eckman, R. and Pines, A. and Tycko, R. and Weitekamp, D. P.} } @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 {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 {662, title = {Multiple Quantum Nmr and Relaxation of an Oriented Ch3 Group}, journal = {Journal of Chemical Physics}, volume = {72}, year = {1980}, note = {J Chem PhysJm229Times Cited:41Cited References Count:26}, pages = {3290-3297}, isbn = {0021-9606}, doi = {Doi 10.1063/1.439565}, url = {://WOS:A1980JM22900051}, author = {Tang, J. and Pines, A.} } @article {663, title = {Multiple Quantum Nmr-Study of Correlation of 2 Methyl-Groups}, journal = {Journal of Chemical Physics}, volume = {73}, year = {1980}, note = {J Chem PhysKh292Times Cited:18Cited References Count:14}, pages = {2512-2513}, isbn = {0021-9606}, doi = {Doi 10.1063/1.440366}, url = {://WOS:A1980KH29200064}, author = {Tang, J. and Pines, A.} } @article {661, title = {Spin-Lattice Relaxation of Reorienting or Tunneling Deuterated Methyl-Groups}, journal = {Journal of Chemical Physics}, volume = {73}, year = {1980}, note = {J Chem PhysKb127Times Cited:10Cited References Count:18}, pages = {172-175}, isbn = {0021-9606}, doi = {Doi 10.1063/1.439903}, url = {://WOS:A1980KB12700025}, author = {Tang, J. and Pines, A. and Emid, S.} } @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 {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} }