The last few years have witnessed a revival of interest in analogues of nucleosides following the discoveries that several of such compounds exhibit powerful antiviral effects. Structural modifications of naturally occurring nucleosides often lead to the discovery of new agents displaying biological and chemotherapeutic activity. A greal deal of effort has been directed towards the modification...

We present a minimal string-inspired supersymmetric SU(4) × SU(2) L × SU(2) R model, and provide a detailed analysis of the symmetry breaking potential in this model, based on a generalisation of that recently proposed by Dvali, Lazarides and Shafi. The model contains a global U(1) R-symmetry and reduces to the MSSM at low energies. However it improves on the MSSM since it explains the magnitud...