Dynamics of spatially nonuniform patterning in the model of blood coagulation

We propose a reaction-diffusion model that describes in detail the cascade of molecular events during blood coagulation. In a reduced form, this model contains three equations in three variables, two of which are self-acceler ated. One of these variables, an activator, behaves in a threshold manner. An inhibitor is also produced autocatalytically, but there is no inhibitor threshold, because it is generated only in the presence of the activator. A ll model variables are set to have equal diffusion coefficients. The model has a stable stationary trivial state, which is spatially uniform and an ex citation threshold. A pulse of excitation runs from the point where the exc itation threshold has been exceeded. The regime of its propagation depends on the model parameters. In a one-dimensional problem, the pulse either sto ps running at a certain distance from the excitation point, or it reaches t he boundaries as an autowave. However, there is a parameter range where the pulse does not disappear after stopping and exists stationarily. The resul ting steady-state profiles of the model variables are symmetrical relative to the center of the structure formed. (C) 2001 American Institute of Physi cs.