Cover figure courtesy of Kim et al, "Rhodamine-123 Staining in Hematopoietic Stem Cells of Young Mice Indicates Mitochondrial Activation Rather Than Dye Efflux." Mouse hematopoietic stem cells were sorted into quiescent (Rh-123^low) and activated (Rh-123^high) subpopulations by flow cytometry and subsequently imaged using confocal microscopy. The fluorescent images derived from the Rh-123 probe have been pseudocolored to indicate fluorescence intensity increasing from blue to red; these images were then overlaid onto visible light images of the same cells. Quiescent hematopoietic stem cells are predominantly Rh-123^low (blue) while activated stem cells have focal accumulations of high fluorescence intensity (red) which correspond to the distribution of mitochondria in the Rh-123^high cells. See Figure 7 of the article. 4106