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A gas sensor made from graphene vertical field effect transistor (VGr-FET) has been fabricated using graphene as the source electrode, C 60 thin film as the semiconductor layer and aluminum thin film as the drain electrode. The on/off ratio of transistor gated by bottom electrode with ionic liquid gel as dielectric layer is derived to be 10 3 from measured source-drain current I ds . The apparent energy barrier height between the graphene and polycrystalline fullerene was calculated from the model of heterojunction diode I-V response curves. The barrier height j BH was altered by the gating potential vertically applied on graphene sheet, resulting the large on/off ratio of the transistor. The effect of surface adsorption of water vapor, oxygen, ammonia and isoprene gas phase molecules on the I ds was measured. The lower limit of detection (LOD) for ammonia (86 ppb) than that of isoprene (420 ppb) is attributed to the donor nature of ammonia contact with p-type graphene, and the adsorbed donor leads to a corresponding positive gating effect to the VGr-FET. This facile, low cost and quick responsive device shows promise for early diagnose of severe human respiratory diseases.

IntraVoxel Incoherent Motion (IVIM) Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) is of great interest for evaluating tissue diffusion and perfusion and producing parametric maps in clinical applications for liver pathologies. However, the presence of macroscopic blood vessels (not capillaries) in a given Region of Interest (ROI) results in a confounding effect that bias the quantification of tissue perfusion. Therefore, it is necessary to identify those voxels affected by blood vessels. In this paper, an efficient algorithm for an automatic identification of blood vessels in a given ROI is proposed. It relies on the sparsity of the spatial distribution of blood vessels. This sparsity prior can be easily incorporated using the all-voxel IVIM-MRI model introduced in this paper. In addition to the identification of blood vessels, the proposed algorithm provides a quantification of blood vessels, tissue diffusion and tissue perfusion of all voxels in a given ROI, in one single step. Besides, two strategies are proposed