Pulsed electric determinant factors

In functional electrical stimulation, the typical stimulation waveform is a train of rectangular pulses. This shape is used because of its effectiveness as well as relative ease of generation. All three parameters of a stimulation train, that is, frequency, amplitude, and pulse-width, have effect on muscle contraction. Generally, the stimulation frequency is kept as low as possible, to prevent muscle fatigue and to conserve stimulation energy. The determining factor is the muscle fusion frequency at which a smooth muscle response is obtained. This frequency varies however, it can be as low as 12-14 Hz and as high as 50 Hz. In most cases, the stimulation frequency is kept constant for a certain application. This is true both for surface as well as implanted electrodes. 

Wouters PC, Alvarez I, Raso J. 2001a. Critical factors determining inactivation kinetics by pulsed electric field food processing. Trends Food Sci Tech 12 112-121. 

Under realistic experimental conditions, additional dispersion may well be introduced as a consequence of factors, such as a finite initial width of excess carrier packet or fluctuations in electric field across a specimen film. Most, if not all, of these factors would be expected to yield a relative dispersion that decreases with increasing specimen thickness. In a well-conducted experimental measurement, a relative dispersion of the order of 20% might typically be achieved, giving a transit pulse similar to that shown in Fig. 3.2 (full line) (from which the mean carrier transit time is readily determined). 

The first one determines the optimal electric field in terms of the evolving wavepackets and while the next two equations guarantee their compliance with the Schrodinger equation under the influence of the laser field e t). To satisfy the demand of a smooth switch on and off behavior of the laserfleld, the shape function s t) is introduced. The penalty factor oq limits the time-averaged laser intensity and T denotes the overall pulse duration. Solving this set of nonlinear differential equations iteratively, leads to a laser field which is optimized for the given task. 

A major factor in the clinical acceptability of electrically enhanced transdermal delivery is its effect on the skin. The pig is a widely accepted animal model for assessing electrically assisted transdermal delivery (Mon-teiro-Riviere, 1990 Riviere and Monteiro-Riviere, 1991). Preliminaiy studies using electroporation (Riviere et al, 1995) conducted with pigs had two objectives. The first was to identify any unique skin changes associated with electroporation and to determine the effect of pulses on iontophoresis-induced irritation. The second objective was to define a pulse/iontophoresis protocol for drug delivery that was minimally irritating. 

In addition to the phase modulation an even more pronounced amplitude modulation is observed (Fig. 8.12, top). After the first pre-pulse (red), the oscillating dipole (blue) is damped simultaneously with the temporal decrease in overlap of the nuclear wavefunctions propagating on the X S+ and the A S+ surface (Fig. 8.12, second panel). Due to the difference in position and shape of both surfaces, the freely evolving nuclear wavepackets get out of phase. Their spatial overlap ai(t) aj(t) rlri(R,t) fj R,t))ii is reduced, which is again a decisive factor for the electron dynamics [Eq. (8.12)]. Its decrease stops the electron dynamics as observable in the damping of the electric dipole oscillation and in the loss of control for large subpulse separations [69]. In this sense K2 is an example for the third factor in Eq. (8.12), which determines the electron dynamics. This third factor can be regarded as time-dependent EC overlap. 

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