Functional Electricity

With modest impairment of blood flow, this mechanism allows for preservation of oxidative metabolism without alteration in electrical function. However, when CPP and therefore CBF are sufficiently low, OEF reaches a maximum and cannot increase further. Brain tissue ceases to function electrically, resulting in a neurologic deficit. Microvascular collapse occurs, and CBV falls. If the oxygen supply falls low enough, the tissue dies. Of critical clinical importance is the observation that the amount of time it takes for tissue to suffer irreversible damage is inversely related to the severity of the ischemic insult. Tissue that is completely deprived of blood will die within a few minutes, but less severely hypoperfused tissue may survive for many hours, and may be saved by timely thrombolysis that restores perfusion, or perhaps by another therapeutic intervention. 

Figure 22 Insulin release rate (normalized to mg/hr per 160 mg device) from insulin-loaded matrix of polyethyloxazolin-poly(methacrylic acid) complex with the application of step-function electric current in 0.9% saline solution (mean from three measurements). ( ) Current on (5mA) (O) current off. (From Ref. 47.)...

An additional point that should be considered is that in the harmonic oscillator approximation, the selection mle for transitions between vibrational states is Ay = 1, where v is the vibrational quantum number and Ay > 1, that is, overtone transitions, which involve a larger vibrational quantum number change, are forbidden in this approximation. However, in real molecules, this rule is slightly relaxed due to the effect of anharmonicity of the oscillator wavefunction (mechanical anharmonicity) and/or the nonlinearity of the dipole moment function (electrical anharmonicity) [55], affording excitation of vibrational states with Ay > 1. However, the absorption cross sections for overtone transitions are considerably smaller than for Ay = 1 transitions and sharply decrease with increasing change in Av. 

McNeal DR (1977) 2000 Years of Electrical Stimulation. In Hambrecht FT, Reswick JB. (eds) Functional Electrical Stimulation. Applications in Neural Prostheses. Marcel Dekker, Inc. New York, p 3... 

In US-A-5113076 a two-terminal radiation detector which is sensitive to two spectral bands of infrared radiation is presented. Two heterojunctions are coupled in series and function electrically as two back-to-back diodes. 

FIGURE 1.29 (a) Depolarization test circuit and (b) depolarization after a heavy side-step-function electric... 

Keywords nanocomposites, dispersion, aspect ratio, in-situ, melt, morphology, tensile properties, glass transition temperature, degradation, functionalization, electrical conductivity, resistivity. 

I j Initiator for polymerization, modified Bessel functions, electric current Electric current density A/m2 ... 

Henry constant for absorption of gas in liquid Free energy change Heat of reaction Initiator for polymerization, modified Bessel functions, electric current Electric current density Adsorption constant Chemical equilibrium constant Specific rate constant of reaction, mass-transfer coefficient Length of path in reactor Lack of fit sum of squares Average molecular weight in polymers, dead polymer species, monomer Number of moles in electrochemical reaction Molar flow rate, molar flux Number chain length distribution Number molecular weight distribution... 

In this section, we describe a solution that employs a net-shaped structure to make flexible electronic film devices conformable to three-dimensional surfaces [18]. Although the base films we presently use are of polyimide and poly(ethylenenaph-thalate) (PEN) — materials that are stiff and not inherently stretchable in a rubberlike sense — our solution includes struts of network structures that twist with the application of tension, as can be seen in Figure 6.3.7. Due to this three-dimensional strut deformation, the whole network structure functions electrically with a unidirectional extension of 25%. We have implemented the pressure sensor network on the surface of an egg and have obtained pressure images in this configuration. 

The Elenbaas-Heller equation (4-55) together with (4-56) permits calculations of the function E I), which is the cmrent-voltage characteristic of the plasma coluttm determined by two material functions electric conductivity a T) and thermal conductivity X(T ). To reduce the number of material functions, it is convenient to introduce, instead of temperatine, the heat flux potential (T) ... 

While electrodes may be integrated as detectors, another possibility is to use the electrodes to stimulate muscles. Electrodes for functional electrical stimulation have been integrated into fabrics to provide actuation stimuli to muscles of the spinal cord of injured and stroke subjects in order to generate or improve lost motor function. 

Kirstein, T., Lawrence, M., Troster, G., 2003. Functional electrical stimulation (FES) with smart textile electrodes. In International Workshop on a New Generation Of Wearable Systems for E-health, Pisa, Italy. 

The modeling and control of movements in this chapter relates to external control of muscles via so-called functional electrical stimulation. Macroscopic viscoelastic models started from the observation that the process of electrical stimulation transforms the viscoelastic material from a compliant, fluent state into the stiff, viscous state. Levin and Wyman [35] proposed a three-element model— damped and undamped elastic element in series. Hill s work [36] demonstrated that the heat transfer depends upon the type of contraction (isometric, slow contracting, etc). The model includes the force generator, damping and elastic elements. Winters [37] generalized Hill s model in a simple enhancement of the original, which... 

Several studies deal with strategies for prolonged standing [ 53-58] and functional electrical stim ulation-aided gait [59-64]. 

Khang, G. and Zajac, F.E., Paraplegic standing controUed by functional electrical stimulation part I — computer model and control-system design part II —computer simulation studies, IEEE Trans. Biomed. Eng. BME-36 873-893,1989. 

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