Fluorescence decay curves of RY3 for Pyrococcus furiosus cells grown at 80°C (measured at 30°C, upper figure, and at 80°C, center figure) and Lactococcus lactis cells grown at 30°C (measured at 30°C, lower figure). Experimental data, fitted curves, residuals, and estimated τavg values (ns) are shown for controls and cells.