Continuous gauge and supersymmetry breaking for open strings on D-branes

We consider freely acting orbifold compactifications, which interpolate in two possible decompactification limits between the supersymmetric type-II s tring and the non-supersymmetric type-0 string. In particular we discuss ho w D-branes are incorporated into these orbifold models. Investigating the o pen string spectrum on D3-branes, we will show that one can interpolate in this way between N = 4 supersymmetric U(N) respectively U(2N) Yang-Mills th eories and non-supersymmetric U(N) x U(N) gauge theories with adjoint massl ess scalar fields plus bifundamental massless fermions in a smooth way. Fin ally, by lifting the orbifold construction to M-theory, we conjecture some duality relations and show that in particular a new supersymmetric branch o f gauge like theories emanate for the non-supersymmetric model.