The concentration dependence of the translational self diffusion rate, D (s), has been measured for a range of micelle and mixed micelle systems. Use of bipolar gradient pulse pairs in the longitudinal eddy current delay experiment minimizes NOE attenuation and is found critical for optimizing sensitivity of the translational diffusion measurement of macromolecules and aggregates. For low volum...

BACKGROUND We tested the hypothesis that in patients with occlusion of the terminal internal carotid artery and/or the proximal middle cerebral artery, a diffusion abnormality of 70 ml or less is accompanied by a diffusion/perfusion mismatch of at least 100%. METHODS Sixty-eight consecutive patients with terminal ICA and/or proximal MCA occlusions and who underwent diffusion/perfusion MRI wit...

The cytoplasm of red blood cells is congested with the oxygen storage protein hemoglobin occupying a quarter of the cell volume. The high protein concentration leads to a reduced mobility; the self-diffusion coefficient of hemoglobin in blood cells is six times lower than in dilute solution. This effect is generally assigned to excluded volume effects in crowded media. However, the collective o...

– Consider uniformly elliptic random walk on Z with independent jump rates across nearest neighbour bonds of the lattice. We show that the infinite volume effective diffusion matrix can be almost surely recovered as the limit of finite volume periodized effective diffusion matrices.  2003 Éditions scientifiques et médicales Elsevier SAS MSC: 60K37; 60K35; 74Q20

The fast reaction limit of a volume-surface reaction-diffusion system is rigorously investigated. We show that as the reaction rate constant goes to infinity, the original system converges to a heat equation with dynamical boundary condition. As a consequence, a dynamical boundary condition can be interpreted as a fast reaction limit of a volume-surface reaction-diffusion system.

We propose a new finite volume method to provide very high-order accuracy for the convection diffusion problem. The main tool is a polynomial reconstruction based on the mean-value to provide the best order. Numerical examples are proposed to show the method efficiency. Key–Words: Finite Volume, very high-order, convection-diffusion, polynomial reconstruction.