A fundamental problem in theoretical neurosciences is the inverse problem of source localization, which aims at locating the sources of the electric activity of the functioning human brain using measurements usually acquired by non-invasive imaging techniques. Such a technique is the electroencephalography (EEG) which measures the e↵ect of the electric activity of active brain regions through v...

PURPOSE To determine exposure to gradient switching fields of adults and children in a magnetic resonance imaging (MRI) scanner by evaluating internal electric fields within realistic models of adult male, adult female, and child inside transverse and longitudinal gradient coils, and to compare these results with compliance guidelines. MATERIALS AND METHODS Patients inside x-, y-, and z-gradi...

Magnetically enhanced inductively coupled plasmas (MEICP) and helicons have complex plasma electric-field coupling between the electric field and the plasma due to the tensor conductivity and multiple-dimensional antenna segments. Computed three-dimensional electric fields and electron temperatures are presented for a helicon reactor demonstrating azimuthal asymmetries and rotations of the elec...

PURPOSE: The capacity to measure conductivity and conductivity anisotropy in vivo and non-invasively has practical significance in a number of biomedical applications. For example, large changes of tissue conductivity have been reported in tumors, strokes and myocardial infarction. Considerable early efforts were focused on the measurement of injected low-frequency currents (1-3). Electric prop...

In microfluidic applications it has been observed that flows with spatial gradients in electrical conductivity are unstable under the application of sufficiently strong electric fields. These electrohydrodynamic instabilities can drive a nonlinear flow despite the low Reynolds number. Such flows hold promise as a simple mechanism for mixing fluids. In this work, the effect of a time periodic el...

We investigate the heterogeneity of electrical conductivity as a new mechanism to stimulate excitable tissues via applied electric fields. In particular, we show that stimulation of axons crossing internal boundaries can occur at boundaries where the electric conductivity of the volume conductor changes abruptly. The effectiveness of this and other stimulation mechanisms was compared by means o...

Effects of ionic concentration gradient on electroosmotic flow (EOF) mixing of one stream of a high concentration electrolyte solution with a stream of a low concentration electrolyte solution in a microchannel are investigated numerically. The concentration field, flow field and electric field are strongly coupled via concentration dependent zeta potential, dielectric constant and electric con...

We investigate the heterogeneity of electrical conductivity as a new mechanism to stimulate excitable tissues via applied electric fields. In particular, we show that stimulation of axons crossing internal boundaries can occur at boundaries where the electric conductivity of the volume conductor changes abruptly. The effectiveness of this and other stimulation mechanisms was compared by means o...

Electroencephalography (EEG) is a non invasive imaging technique that measures the effect of the electric activity of active brain regions, called sources, through values of the electric potential furnished by a set of electrodes placed at the surface of the scalp. A fundamental problem there is the inverse problem of source localization which aims at locating the sources of the electric activi...