We revisit the problem of pinning a reaction-diffusion front by defect, in particular reaction-free region. Using collective variables for and numerical simulations, we compare behaviors bistable monostable front. A can be pinned as confirmed criterion, analysis time independant simulations. Conversely, never pinned, it gives rise to secondary pulse past defect calculate this takes appear. Thes...

The kinetic of the heterogeneous chemical reaction of aluminum hydroxide and fluosilicic acid was studied. It was found that the diffusion of the reactants through the porous silica coating to the aluminum hydroxide surface and the interfacial chemical reaction between the diffusing reactant and aluminum hydroxide platelets control the overall reaction rate. These two phenomena were studied...

We propose a simple model for the control of DNA replication in which the rate of initiation of replication origins is controlled by protein-DNA interactions. Analyzing recent data from Xenopus frog embryos, we find that the initiation rate is reaction limited until nearly the end of replication, when it becomes diffusion limited. Initiation of origins is suppressed when the diffusion-limited s...