Figure 1 shows a proton magnetic resonance image of skin taken from a hairless rat. In addition, MR images of skin with electric fields applied have shown that under conditions of pulsed electrical fields the effective diffusion coefficient of water is greatly enhanced in the stratum corneum. Current work focuses on the effects of various chemical species on water and other solute transport in the skin as measured with magnetic resonance imaging methods. Related work deals with the effects of pulsed electrical field on diffusion and relaxation properties in cancer tumors. Image of a vertical slice of skin from a hairless rat.
Light regions indicate high proton signal.
NMR studies have dealt with the fundamental aspects of diffusive, electrophoretic, and electroosmotic transport in porous media. A theoretical framework has been developed using the method of volume averaging to analyze experimental data obtained from diffusion measurements and T1 relaxation measurements. Oligonucleotide diffusion coefficients measured in Pluronics indicate that the major mode of transport of these compounds is not reptation. Theoretical analysis using volume averaging methods in combination with experimental measurements using NMR has resulted in further understanding of transport in porous materials. This figure shows velocity profiles for the case of 50 Volts applied across 10 cm of a 1 cm diameter glass tube packed with 2 to 4 mm spherical glass particles.