Non-homogeneous random walks, subdiffusive migration of cells and   anomalous chemotaxis
  This paper is concerned with a non-homogeneous in space and non-local in time random walk model for anomalous subdiffusive transport of cells. Starting with a Markov model involving a structured probability density function, we derive the non-local in time master equation and fractional equation for the probability of cell position. We show the structural instability of fractional subdiffusive equation with respect to the partial variations of anomalous exponent. We find the criteria under which the anomalous aggregation of cells takes place in the semi-infinite domain. 
S. Fedotov, A. O. Ivanov, A. Y. Zubarev
cond-mat.stat-mech nlin.AO q-bio.CB