A fluorescent lifetime/phase modulation fluorometer with necessary accessories (X-Y graphic plotter, matrix printer, IBM-PC, photomultiplier tubes, etc.) is requested. The use of the instrument is to be shared among researchers in the School of Medicine at the SUNY at Buffalo. The objects requiring the lifetime/phase modulation fluorometer include, but are not limited to the studies of metal ion interaction with macromolecules (enzymes), molecular mechanisms of membrane fusion for model as well as biological membranes, including molecular mechanisms of virus and bacterial infections to host cells, protein and lipid interaction, the role of sterols at various cellular levels and the conformational change in intrinsic proteins (ionic channels, etc.) with membranes and immunogenic interactions on cell surfaces.