  Based on the low-energy effective field theory of D-branes, the mass spectrum
of an extended Standard Model with two-Higgs doublets used to generate all the
mass terms is investigated. Besides the gauge bosons, the fermion mass spectrum
is weighted by the Higgs VEVs with a partial hierarchy and the smallness of
neutrino masses is exhibited. With reference to the known data, the involved
scales of the model are approached.
