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α-Tocopherol (vitamin E) is an essential nutrient for all vertebrates. From the eight naturally occurring members of the vitamin E family, α-tocopherol is the most biologically active species and is selectively retained in tissues. The hepatic α-tocopherol transfer protein (TTP) preferentially selects dietary α-tocopherol and facilitates its transport through the hepatocyte and its secretion to the circulation. In doing so, TTP regulates body-wide levels of α-tocopherol. The mechanisms by which TTP facilitates α-tocopherol trafficking in hepatocytes are poorly understood. We found that the intracellular localization of TTP in hepatocytes is dynamic and responds to the presence of α-tocopherol. In the absence of the vitamin, TTP is localized to perinuclear vesicles that harbor CD71, transferrin, and Rab8, markers of the recycling endosomes. Upon treatment with α-tocopherol, TTP- and α-tocopherol-containing vesicles translocate to the plasma membrane, prior to secretion of the vitamin to the exterior of the cells. The change in TTP localization is specific to α-tocopherol and is time- and dose-dependent. The aberrant intracellular localization patterns of lipid binding-defective TTP mutants highlight the importance of protein-lipid interaction in the transport of α-tocopherol. These findings provide the basis for a proposed mechanistic model that describes TTP-facilitated trafficking of α-tocopherol through hepatocytes.

In this paper, we propose a depth restoration method using a novel superpixel technique. Guided by a normal map reconstructed from the raw depth data, this technique over-segments RGB-D images into many small regions where their depth is assumed to be smooth. As the raw depth data is incomplete, we further introduce a depth confidence map to identify the regions which are more reliable. With the produced superpixels, we can restore the incomplete depth map using a per-superpixel linear regression. A multiresolution su-perpixel strategy is employed when some superpixels do not contain enough valid data. Experiments show that the proposed depth restoration method can effectively fill the wide gaps along depth discontinuities without blurring the object boundaries and the depth discontinuities.