89 research outputs found

    Pressurized carbonization of coal liquefaction by-product materials: Fluor Advanced Liquefaction and Parsons' POGO processes

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    Experiments were performed to determine the results of carbonization under pressure of three coal liquefaction product (or by-product) materials and thus supply data needed as a design base for two concepts for advanced coal liquefaction plants. Solid-liquid separation underflow (SLSU) and solvent from a hydroextraction process were carbonized at 900/sup 0/F in an inert atmosphere at pressures up to 400 psig. Vacuum still bottoms from the H-Coal process were pyrolyzed at 1100/sup 0/F in a methane atmosphere at 400 psig. Results from carbonization of hydroextraction solvent and SLSU show that (1) only 1 to 7 percent of the solvent is degraded during carbonization at 900/sup 0/F and 400 psig, (2) the heavier fraction of the residue contributed the most toward coke formation, and (3) increased pressure increases the degree of coking of the heavier fractions. Results from pyrolysis of the vacuum still bottoms material at 1100/sup 0/F and 400 psig indicated that (1) small amounts of liquid are produced, (2) a significant quality of gas is produced, and (3) higher temperature will probably be required to produce free-flowing char

    αB Crystallin Is Apically Secreted within Exosomes by Polarized Human Retinal Pigment Epithelium and Provides Neuroprotection to Adjacent Cells

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    αB Crystallin is a chaperone protein with anti-apoptotic and anti-inflammatory functions and has been identified as a biomarker in age-related macular degeneration. The purpose of this study was to determine whether αB crystallin is secreted from retinal pigment epithelial (RPE) cells, the mechanism of this secretory pathway and to determine whether extracellular αB crystallin can be taken up by adjacent retinal cells and provide protection from oxidant stress. We used human RPE cells to establish that αB crystallin is secreted by a non-classical pathway that involves exosomes. Evidence for the release of exosomes by RPE and localization of αB crystallin within the exosomes was achieved by immunoblot, immunofluorescence, and electron microscopic analyses. Inhibition of lipid rafts or exosomes significantly reduced αB crystallin secretion, while inhibitors of classic secretory pathways had no effect. In highly polarized RPE monolayers, αB crystallin was selectively secreted towards the apical, photoreceptor-facing side. In support, confocal microscopy established that αB crystallin was localized predominantly in the apical compartment of RPE monolayers, where it co-localized in part with exosomal marker CD63. Severe oxidative stress resulted in barrier breakdown and release of αB crystallin to the basolateral side. In normal mouse retinal sections, αB crystallin was identified in the interphotoreceptor matrix. An increased uptake of exogenous αB crystallin and protection from apoptosis by inhibition of caspase 3 and PARP activation were observed in stressed RPE cultures. αB Crystallin was taken up by photoreceptors in mouse retinal explants exposed to oxidative stress. These results demonstrate an important role for αB crystallin in maintaining and facilitating a neuroprotective outer retinal environment and may also explain the accumulation of αB crystallin in extracellular sub-RPE deposits in the stressed microenvironment in age-related macular degeneration. Thus evidence from our studies supports a neuroprotective role for αB crystallin in ocular diseases
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