Adhesion-guided multicellular assembly: a commentary upon the postulates, real and imagined, of the differential adhesion hypothesis, with special attention to computer simulations of cell sorting.

The condition for local dynamic stability of the trajectories of a metabolic network in the presence of conserved moieties and steady state subnetworks is given.     

The hierarchical structure of metabolic networks and the construction of efficient metabolic simulators

Methods are presented for the efficient simulation of large scale metabolic networks based upon the hierarchical structure of such networks and the formation of steady-state aggregations. The methods are dynamic and result in a varying time scale which is always consonant with the response of the network. An algorithm for the generation of reduced equivalent networks is presented. Problems of accuracy and stability are discussed. Special methods such as cascading and telescoping are presented for speeding the solution of the steady-state aggregations.