6,957 research outputs found

    Water resource problems of energy projects in the Colorado River Basin

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    The successful development of western coal and oil shale deposits is dependent, to a significant degree, on the availability of adequate water supplies. EQL is involved in a study of the aggregate effects of various energy activities in the upper Colorado River Basin on downstream water quantity and quality. These activities will tend to reduce the available water in the river, and could increase its salinity, which is already so high as to interfere with downstream domestic and agricultural use

    Effect of multiple transverse modes in self-mixing sensors based on vertical-cavity surface-emitting lasers

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    We investigate the effect of coexisting transverse modes on the operation of self-mixing sensors based on vertical-cavity surface-emitting lasers (VCSELs). The effect of multiple transverse modes on the measurement of displacement and distance were examined by simulation and in laboratory experiment. The simulation model shows that the periodic change in the shape and magnitude of the self-mixing signal with modulation current can be properly explained by the different frequency-modulation coefficients of the respective transverse modes in VCSELs. The simulation results are in excellent agreement with measurements performed on single-mode and multimode VCSELs and on self-mixing sensors based on these VCSELs

    Neuroprotective roles of asiaticoside on hydrogen peroxide-induced toxicity in SH-SY5Y cells

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    This study aims to determine whether the neuroprotective role of asiaticoside at maximum non-toxic dose (MNTD) or half MNTD (½MNTD) on H2O2-induced neurotoxicity in SH-SY5Y cells was mediated by regulation of reactive oxygen species (ROS) and nitric oxide (NO) through inducible nitric oxide synthase (iNOS) and heme-oxygenase 1 (HO-1). The levels of ROS, NO, iNOS and HO-1 in SH-SY5Y cells pre-treated with asiaticoside ½MNTD were significantly reduced by 15.3, 55.6, 24.8 and 6.7 %, respectively as compared to the H2O2 treatment group. Cells pre-treated MNTD only reduced the iNOS level significantly. Asiaticoside, particularly at ½MNTD reduced the ROS, NO and iNOS levels. Contrarily, the HO-1 expression was down-regulated when treated with asiaticoside, which further suggest that asiaticoisde exerted its neuroprotective effects via HO-1 regulation.Keywords: Asiaticoside; Heme-oxygenase 1; Inducible nitric oxide synthase; Nitric oxide; Reactive oxygen species

    Electronic Structure of Electron-doped Sm1.86Ce0.14CuO4: Strong `Pseudo-Gap' Effects, Nodeless Gap and Signatures of Short Range Order

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    Angle resolved photoemission (ARPES) data from the electron doped cuprate superconductor Sm1.86_{1.86}Ce0.14_{0.14}CuO4_4 shows a much stronger pseudo-gap or "hot-spot" effect than that observed in other optimally doped nn-type cuprates. Importantly, these effects are strong enough to drive the zone-diagonal states below the chemical potential, implying that d-wave superconductivity in this compound would be of a novel "nodeless" gap variety. The gross features of the Fermi surface topology and low energy electronic structure are found to be well described by reconstruction of bands by a 2×2\sqrt{2}\times\sqrt{2} order. Comparison of the ARPES and optical data from the samesame sample shows that the pseudo-gap energy observed in optical data is consistent with the inter-band transition energy of the model, allowing us to have a unified picture of pseudo-gap effects. However, the high energy electronic structure is found to be inconsistent with such a scenario. We show that a number of these model inconsistencies can be resolved by considering a short range ordering or inhomogeneous state.Comment: 5 pages, 4 figure

    Removal of steroid estrogens in carbonaceous and nitrifying activated sludge processes

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    This is the post-print version of the final paper published in Chemosphere. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.A carbonaceous (heterotrophic) activated sludge process (ASP), nitrifying ASP and a nitrifying/denitrifying ASP have been studied to examine the role of process type in steroid estrogen removal. Biodegradation efficiencies for total steroid estrogens (ΣEST) of 80 and 91% were recorded for the nitrifying/denitrifying ASP and nitrifying ASP respectively. Total estrogen biodegradation (ΣEST) was only 51% at the carbonaceous ASP, however, the extent of biodegradation in the absence of nitrification clearly indicates the important role of heterotrophs in steroid estrogen removal. The low removal efficiency did not correlate with biomass activity for which the ASPcarbonaceous recorded 80 μg kg−1 biomass d−1 compared to 61 and 15 μg kg−1 biomass d−1 at the ASPnitrifying and ASPnitrifying/denitrifying respectively. This finding was explained by a moderate correlation (r2 = 0.55) between total estrogen loading (ΣEST mg m−3 d−1) and biomass activity (μg ΣEST degraded kg−1 d−1) and has established the impact of loading on steroid estrogen removal at full-scale. At higher solids retention time (SRT), steroid estrogen biodegradation of >80% was observed, as has previously been reported. It is postulated that hydraulic retention time (HRT) is as important as SRT as this governs both reaction time and loading. This observation is based on the high specific estrogen activity determined at the ASPcarbonaceous plant, the significance of estrogen loading and the positive linear correlation between SRT and HRT.Public Utilities Board of Singapore, Anglian Water Ltd., Severn Trent Water Ltd., Thames Water Utilities Ltd., United Utilities Plc., and Yorkshire Water Services Ltd

    Glucose metabolism and oscillatory behavior of pancreatic islets

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    A variety of oscillations are observed in pancreatic islets.We establish a model, incorporating two oscillatory systems of different time scales: One is the well-known bursting model in pancreatic beta-cells and the other is the glucose-insulin feedback model which considers direct and indirect feedback of secreted insulin. These two are coupled to interact with each other in the combined model, and two basic assumptions are made on the basis of biological observations: The conductance g_{K(ATP)} for the ATP-dependent potassium current is a decreasing function of the glucose concentration whereas the insulin secretion rate is given by a function of the intracellular calcium concentration. Obtained via extensive numerical simulations are complex oscillations including clusters of bursts, slow and fast calcium oscillations, and so on. We also consider how the intracellular glucose concentration depends upon the extracellular glucose concentration, and examine the inhibitory effects of insulin.Comment: 11 pages, 16 figure
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