  We investigate the particle production in a toroidal compactified spacetime
due to the expansion of a Friedmann cosmological model in R3 x S1 outside a
U(1) local cosmic string. The case of a Friedmann spacetime is also
investigated when torsion is incorporated in the connection. We present a
generalization to toroidal compactification of p extra dimensions, where the
topology is given by R3 x T^p. Some implications are presented and discussed.
Besides the dynamics of spacetime, we also investigate in details the physical
consequences of the topological transformations.
