  We discuss gauge theories on D3 branes embedded in special non-tachyonic
orientifolds of the 0B string theory. In general, they correspond to
non-supersymmetric SU(N) gauge theories with scalars in the adjoint
representation and spinors in the (anti-)symmetric representation. We study
these theories via the AdS/CFT correspondence and present evidence of their
relation to N=4 SYM in the planar limit. We also discuss finite N properties,
focusing in particular on the renormalization group flow. Up to two loops, the
logarithmic running of the gauge coupling is described by the dilaton tadpole
and the cosmological constant that naturally emerge on the string theory side.
