200 - Bioelectrochemical System Models, Electromagnetic Interactions and Noise

Abstract

A general approach to the modelling of bioelectrochemical processes is discussed, which relies on multi—compartment models. This approach can be applied to different types of biosystems, e.g., blood cells, ion flows through membranes, etc. The basic idea is that each net input flux Φ ij entering the i-th compartment can always be splitted into two unidirectional microscopic fluxes Φ′ ij and Φ″ ij such that Φ ij = Φ′ ij Φ″ ij , where Φ′ ij is a true input ( J in ) flow or a production ( P *) rate, and Φ″ ij is a true output ( J out ) flow or a disappearance ( D *) rate. In doing so, it is always possible to define a zero—flux equilibrium condition Φ′ ij = Φ″ ij which allows us to correctly apply Onsager's reciprocity conditions to model constitutive equations, in order to test their physical reliability. A general approach, based on mass—action law statistics, is proposed, which enables us to evaluate unidirectional non—linear fluxes when actual bioelectrochemical forces are not known in detail. Possible interactions of the electromagnetically active populations with electromagnetic fields are discussed. Finally, the noise associated with Φ k ij ( k = J in , J out , P *, D *) is considered. The noiseless value Φ k ij ( t) gives the average occurrence rate of the corresponding Poisson process at t during any transient. We can show that the related autocorrelation noise function R k ij ( t 1, t 2) can be evaluated from this noiseless flux: R k ij ( t 1, t 2) = Φ k ij ( t 1) δ( t 2− t 1), δ( t 2− t 1) being the Dirac delta function. Therefore, it becomes apparent that a quantitative amount of information on the flux values can be obtained from noise measurements. Recent results relevant to the white cell system of human beings are presented.