Carl D. Gregory

Learn More
Exercise-induced decreases in the (1)H transverse relaxation rate (R(2)) of muscle have been well documented, but the mechanism remains unclear. In this study, the hypothesis was tested that R(2) decreases could be explained by pH decreases and apparent intracellular volume (V(i)') increases. (31)P and (1)H spectroscopy, biexponential R(2) analysis, and(More)
The standard model for the origin of galactic magnetic fields is through the amplification of seed fields via dynamo or turbulent processes to the level consistent with present observations. Although other mechanisms may also operate, currents from misaligned pressure and temperature gradients (the Biermann battery process) inevitably accompany the(More)
Shimming is important. Noniterative methods are desirable. Such methods exist for shimming a spectrometer with pulsed field gradients, generally based on field maps made by spin-warp Fourier imaging. For spectrometers with no pulsed gradients (or for cases where T2 is too short to permit echo imaging), an alternative method is presented:(More)
Ultrasound and magnetic resonance imaging show contrast between the inner and outer myometrium, which is useful in the diagnosis of gynecological disorders. To determine whether the image contrast is associated with biochemical differences between these myometrial regions, phosphorus metabolite concentrations in the inner one third of the myometrium (the(More)
Quantitative lactate imaging and spectroscopy were performed on phantoms and on electrically stimulated, excised frog skeletal muscle at macroscopic and microscopic resolutions. Lactate selectivity was achieved by use of a zero-quantum/double-quantum coherence (ZQC/DQC) lactate filter, which suppressed all signals besides lactate, including water and lipid,(More)
In 1H NMR spectroscopic studies of fatiguing skeletal muscles, two peaks consistently arise near 1.3 ppm, typically 15-20 Hz apart at 300 MHz. From a variety of NMR and biochemical evidence, both peaks are identified as lactate. Both the CH3 and CH protons of lactate experience the same shift in intact muscle; this rules out chemical bonding or(More)