@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 {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 {278, title = {Volume-selective magnetic resonance imaging using an adjustable, single-sided, portable sensor}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {105}, year = {2008}, note = {P Natl Acad Sci USA389LBTimes Cited:11Cited References Count:29}, month = {Dec 30}, pages = {20601-20604}, abstract = {

Portable, single-sided NMR sensors can operate under conditions inaccessible to conventional NMR while featuring lower cost, portability, and the ability to analyze arbitrary-sized objects. Such sensors can nondestructively probe the interior of samples by collecting images and measuring relaxation and diffusion constants, and, given careful shimming schemes, even perform chemical analysis. The inherently strong magnetic-field gradients of single-sided sensors developed so far has prevented imaging of materials with high water content, such as biological tissues, over large volumes whereas designs with more homogeneous fields suffer from low field strength and typically cannot probe volumes larger than approximate to 10 cm(3). We present a design with a continuously adjustable sensitive volume, enabling the effective volume to be enlarged several fold. This capability allows for imaging in reasonable times of much bigger objects and opens the door to the possibility of clinical imaging with portable sensors. We demonstrate MRI in axial and sagittal planes, at different depths of the sensitive volume and T(1)-weighted contrast in a tissue sample.

}, keywords = {xenon}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0811222106}, url = {://WOS:000262092800008}, author = {Paulsen, J. L. and Bouchard, L. S. and Graziani, D. and Blumich, B. and Pines, A.} } @article {308, title = {High-resolution NMR spectroscopy with a portable single-sided sensor}, journal = {Science}, volume = {308}, year = {2005}, note = {Science931JTTimes Cited:89Cited References Count:7}, month = {May 27}, pages = {1279-1279}, keywords = {fields}, isbn = {0036-8075}, doi = {Doi 10.1126/Science.1108944}, url = {://WOS:000229482300037}, author = {Perlo, J. and Demas, V. and Casanova, F. and Meriles, C. A. and Reimer, J. and Pines, A. and Blumich, B.} }