The invention relates generally to G protein coupled receptors and in particular to agonists and antagonists of G protein receptors and methods of using the same. In one nonlimiting embodiment, the HIV strain is resistant to a -D-1,3-dioxolanyl nucleoside. The nonlinear distortion compensation circuit is operable to use the sets of nonlinear distortion model parameter values for processing of signals from the plurality of communication partners. The novel findings of cell selective toxicity towards potential disease causing cells indicate a potential utility of ZnO nanoparticle in the treatment of cancer andor autoimmunity.