Associate Research Physicist
Ph.D., Physics, College of William and Mary (Williamsburg, VA, 1989)
UC Davis Nuclear Magnetic Resonance Facility
Biomedical Engineering Graduate Group
Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). NMR and MRI are used to noninvasively measure material properties (strain, temperature, viscosity, velocity) of materials. Also, NMR and MRI hardware design for use as sensors.
UC Davis NMR Facility
The NMR Facility provides qualified researchers in the biological, medical, and physical sciences access to state-of-the-art NMR instrumentation for spectroscopy and imaging. At present the Facility operates 10 spectrometers of varying purposes and capabilities, four of which are housed in Building MS1-D and four, operated jointly with the Chemistry Department, in the Chemistry building. Four instruments are largely devoted to structural characterization of organic and inorganic molecules. Two vertical bore spectrometers are used primarily for solution studies of biomolecules, with an additional vertical bore instrument for in vitro biological studies. Two horizontal magnet bore spectrometers are utilized for in vivo spectroscopy and imaging of small animals, imaging of materials, and in vitro spectroscopy of perfused organs. One spectrometer is devoted to solid state NMR spectroscopy. All of the spectrometers are multinuclear and a large variety of liquids, solids, surface, and imaging coils are available for use. The Facility also has Linux computers for off-line data processing.
Garcia, S., Walton, J. H., Armstrong, B., Han, S. & McCarthy, M. J. L-band Overhauser dynamic nuclear polarization. Journal of Magnetic Resonance In Press (2010).
Peng, B. J., Walton, J. H., Cherry, S. R. & Willig-Onwuachi, J. Studies of the interactions of an MRI system with the shielding in a combined PET/MRI scanner. Physics in Medicine and Biology 55, 265-280 (2009).
Chen, Y. J., Lam, T. I., Anderson, S. E., Walton, J. H. & O’Donnell, M. E. Blood-brain barrier Na-K-Cl cotransporter and Na/H exchanger: therapeutic targets for ischemia-induced brain Na uptake and edema formation. Journal of Cerebral Blood Flow and Metabolism 29, S489-S489 (2009).
Neu, C. P. & Walton, J. H. Displacement encoding for the measurement of cartilage deformation. Magnetic Resonance in Medicine 59, 149-155 (2008).
Perez-Donoso, A. G., Greve, L. C., Walton, J. H., Shackel, K. A. & Labavitch, J. M. Xylella fastidiosa infection and ethylene exposure result in xylem and water movement disruption in grapevine shoots. Plant Physiol. 143, 1024-1036 (2007).
Reiter, D. A., Fathallah, F. A. & Walton, J. H. Non-Invasive Evaluation of the Effect of Stooped Posture on Spinal Intervertebral Discs Using MRI. Human Factors and Ergonomics Society Annual Meeting Proceedings 50, 1274-1278 (2006).
Pichler, B. J. et al. Performance test of an LSO-APD detector in a 7-T MRI scanner for simultaneous PET/MRI. Journal of Nuclear Medicine 47, 639-647 (2006).
McCarthy, M. J. et al. Measurement of fluid food viscosity using microfabricated radio frequency coils. J. Texture Stud. 37, 607-619 (2006).
d’Avila, M. A. et al. A novel gravity-induced flow transition in two-phase fluids. Physics of Fluids 18 (2006).
Neu, C. P., Hull, M. L., Walton, J. H. & Buonocore, M. H. MRI-Based technique for determining nonuniform deformations throughout the volume of articular cartilage explants. Magnetic Resonance in Medicine 53, 321-328 (2005).
Neu, C. P., Hull, M. L. & Walton, J. H. Error optimization of a three-dimensional magnetic resonance imaging tagging-based cartilage deformation technique. Magnetic Resonance in Medicine 54, 1290-1294 (2005).
Neu, C. P., Hull, M. L. & Walton, J. H. Heterogeneous three-dimensional strain fields during unconfined cyclic compression in bovine articular cartilage explants. J Orthop Res 23, 1390-1398 (2005).
Goloshevsky, A. G. et al. Development of low field nuclear magnetic resonance microcoils. Rev Sci Instrum 76, 24101-24101-24106 (2005).
Goloshevsky, A. G. et al. Nuclear magnetic resonance imaging for viscosity measurements of non-Newtonian fluids using a miniaturized RF coil. Meas Sci Technol 16, 513-518 (2005).
Goloshevsky, A. G. et al. Integration of biaxial planar gradient coils and an RF microcoil for NMR flow imaging. Meas Sci Technol 16, 505-512 (2005).
d’Avila, M. A. et al. Magnetic resonance imaging (MRI): A technique to study flow an microstructure of concentrated emulsions. Brazilian Journal of Chemical Engineering 22, 49-60 (2005).
McCarthy, M. J. et al. Development of microscale NMR sensors for control of food processing. Food Sci Biotechnol 13, 848-851 (2004).
Walton, J. H. et al. A micromachined double-tuned NMR microprobe. Analytical Chemistry 75, 5030-5036 (2003).
Shapley, N. C. et al. Complex flow transitions in a homogeneous, concentrated emulsion. Physics of Fluids 15, 881-891 (2003).
Naruke, T. et al. in Acta Horticulturae Vol. 599 (eds B.E. Verlinden, B.M. Nicolai, & J. De Baerdemaeker) 265-271 (2003).
d’Avila, M. A. et al. Mixing of concentrated oil-in-water emulsions measured by nuclear magnetic resonance imaging. Physics of Fluids 15, 2499-2511 (2003).