Molecular characterization of cell types using single-cell transcriptome sequencing is revolutionizing cell biology and enabling new insights into the physiology of human organs. We created a human reference atlas comprising nearly 500,000 cells from 24 different tissues and organs, many from the same donor. This atlas enabled molecular characterization of more than 400 cell types, their distribution across tissues, and tissue-specific variation in gene expression. Using multiple tissues from a single donor enabled identification of the clonal distribution of T cells between tissues, identification of the tissue-specific mutation rate in B cells, and analysis of the cell cycle state and proliferative potential of shared cell types across tissues. Cell type–specific RNA splicing was discovered and analyzed across tissues within an individual.

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International audienceThe optical and vibrational properties of silicon nanocrystals are studied in two systems elaborated by evaporation. The first one is constituted by a thick SiO layers. The second one is a multilayered sample made by successive evaporations of SiO and SiO2 layers with controlled thicknesses. The luminescence and Raman spectra are fitted by phenomenological exciton and phonon confinement models accounting for the size distribution of the embedded nanocrystals. The coherence between the two models and experimental data is demonstrated and gives support to the notion of exciton and phonon confinement effect in silicon nanocrystals embedded within silica matrix