Uncoupling, electrical-mechanical

The uncoupled response of a piezoelectric sample to elastic shock compression is determined on the assumption that the mechanical response of the material is independent of any electric fields that may be present. In this approximation, a steady shock is introduced into material at rest while the... 

Uncoupled solutions for current and electric field give simple and explicit descriptions of the response of piezoelectric solids to shock compression, but the neglect of the influence of the electric field on mechanical behavior (i.e., the electromechanical coupling effects) is a troublesome inconsistency. A first step toward an improved solution is a weak-coupling approximation in which it is recognized that the effects of coupling may be relatively small in certain materials and it is assumed that electromechanical effects can be treated as a perturbation on the uncoupled solution. 

The basic mechanism underlying the toxicity of salicylate is the uncoupling of oxidative phosphorylation. For oxidative phosphorylation to take place, there is a requirement of a charge difference between the intermembrane space and the matrix of the mitochondria (Fig. 7.60). This is achieved when electrons move down the chain of multienzyme complexes and electron carriers (the electron transport chain), causing protons to move from the mitochondrial matrix to the intermembrane space. Consequently, a pH difference builds up, which is converted into an electrical potential across the membrane of approximately 200 mV over 8 nm. 

S.K. Jain, R.B. Schuessler, J.E. Saffitz, Mechanisms of delayed electrical uncoupling induced by ischemic preconditioning, Circ Res 92, 1138-1144 (2003). 

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