Changes in extracellular space (ECS) diffusion parameters in astrogliotic tissue around a unilateral cortical stab wound were determined from concentration-time profiles of tetramethylammonium (TMA(+)) using TMA(+)-selective microelectrodes. Three diffusion parameters-ECS volume fraction alpha (alpha = ECS volume/ total tissue volume), tortuosity lambda (lambda(2) = D/ADC; where D is the free a...

6 Transient electronics is a class of technology that involves components which physically disappear, in whole or in part, at prescribed rates and at programmed times. Enabled devices include medical monitors that fully resorb when implanted into the human body (“bio-resorbable”) to avoid long-term adverse effects, or environmental monitors that dissolve when exposed to water (“eco-resorbable”)...

Many cellular and subcellular biological processes can be described in terms of diffusing and chemically reacting species (e.g. enzymes). Such reaction-diffusion processes can be mathematically modelled using either deterministic partial-differential equations or stochastic simulation algorithms. The latter provide a more detailed and precise picture, and several stochastic simulation algorithm...

The functional properties of multi-component materials are often determined by a rearrangement of their different phases and by chemical reactions of their components. In this contribution, a material model is presented which enables computational simulations and structural optimization of solid multi-component systems. Typical Systems of this kind are anodes in batteries, reactive polymer blen...

We report on chemoconvective pattern formation phenomena observed in a two-layer system of miscible fluids filling a vertical Hele-Shaw cell. We show both experimentally and theoretically that the concentration-dependent diffusion coupled with frontal acid-base neutralization can give rise to the formation of a local unstable zone low in density, resulting in a perfectly regular cell-type conve...

We consider the Smoluchowski equation with a coordinate-dependent reactivity and obtain asymptotic expansions for the survival probability and the mean lifetime as power series in the diffusion constant. The coefficients in this expansion may depend on both temporal and spatial variables. Using the present results together with the previously derived expansion for the fast diffusion limit, we a...

Slow invariant manifolds (SIM) are calculated for spatially inhomogeneous closed reactive systems to obtain a model reduction. A simple oxygen dissociation reaction-diffusion system is evaluated. SIMs are calculated using a robust method of finding the system’s equilibria and integrating to find heteroclinic orbits. Diffusion effects are obtained by using a Galerkin method to project the infini...