Changing the resonant nucleus by altering the static field, compensation of γ and B effects in T and T* measurements of porous media.

Multinuclear H, C, and Na magnetic resonance (MR) has many advantages for studying porous media systems containing hydrocarbons and brine. In recent work, we have explored changing the nucleus measured, keeping the Larmor frequency constant, by changing the static magnetic field B. Increasing the static B field distorts the field in the pore space due to susceptibility mismatch between the matrix and pore fluid.

Fast spin echo MRI of reservoir core plugs with a variable field magnet.

Fast Spin Echo MRI is now widely employed in biomedicine for proton density and T contrast imaging. Fast Spin Echo methods provide rapid data acquisition by employing multiple echoes to determine multiple k-space lines with single excitations. Due to the multi-exponential behavior of T in typical porous media, and the strong dependence of T on the details of the experiment, acquiring a proton density image with Fast Spin Echo methods requires favorable sample and acquisition parameters.

Studies of periodic seawater spray icing with unilateral NMR.

Sea water ice has a complicated pore structure consisting of brine-filled pockets within a solid ice matrix. In this work, an unilateral Nuclear Magnetic Resonance instrument was used to characterize the evolution of sea-ice brine inclusions in two types of ice: stationary seawater ice and seawater spray ice formed by periodic spraying on horizontal and vertical surfaces. The portable unilateral NMR was capable of measuring very low amounts of brine (<10% of the water-filled volume).

A parallel-plate RF probe and battery cartridge for Li ion battery studies.

A new parallel-plate resonator for Li ion cell studies is introduced along with a removable cartridge-like electrochemical cell for lithium ion battery studies. This geometry separates the RF probe from the electrochemical cell permitting charge/discharge of the cell outside the magnet and introduces the possibility of multiplexing samples under test. The new cell has a geometry that is similar to that of a real battery, unlike the majority of cells employed for MR/MRI studies to this point.

3D Stationary electric current density in a spherical tumor treated with low direct current: an analytical solution.

Electrotherapy with direct current delivered through implanted electrodes is used for local control of solid tumors in both preclinical and clinical studies. The aim of this research is to develop a solution method for obtaining a three-dimensional analytical expression for potential and electric current density as functions of direct electric current intensity, differences in conductivities between the tumor and the surrounding healthy tissue, and length, number and polarity of electrodes. The influence of these parameters on electric current density in both media is analyzed.

Modified Gompertz equation for electrotherapy murine tumor growth kinetics: predictions and new hypotheses.

Background: Electrotherapy effectiveness at different doses has been demonstrated in preclinical and clinical studies; however, several aspects that occur in the tumor growth kinetics before and after treatment have not yet been revealed. Mathematical modeling is a useful instrument that can reveal some of these aspects. The aim of this paper is to describe the complete growth kinetics of unperturbed and perturbed tumors through use of the modified Gompertz equation in order to generate useful insight into the mechanisms that underpin this devastating disease.