3,559 research outputs found

    Forchheimer flow to a well-considering time-dependent critical radius

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    Previous studies on the non-Darcian flow into a pumping well assumed that critical radius (RCD) was a constant or infinity, where RCD represents the location of the interface between the non-Darcian flow region and Darcian flow region. In this study, a two-region model considering time-dependent RCD was established, where the non-Darcian flow was described by the Forchheimer equation. A new iteration method was proposed to estimate RCD based on the finite-difference method. The results showed that RCD increased with time until reaching the quasi steady-state flow, and the asymptotic value of RCD only depended on the critical specific discharge beyond which flow became non-Darcian. A larger inertial force would reduce the change rate of RCD with time, and resulted in a smaller RCD at a specific time during the transient flow. The difference between the new solution and previous solutions were obvious in the early pumping stage. The new solution agreed very well with the solution of the previous two-region model with a constant RCD under quasi steady flow. It agreed with the solution of the fully Darcian flow model in the Darcian flow region

    Etanercept Inhibits Pro-inflammatory Cytokines Expression in Titanium Particle-Stimulated Peritoneal Macrophages

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    Purpose: To investigate the inhibitory role of Etanercept in pro-inflammatory cytokines such as TNF-α, IL-1β and IL-6 production in titanium (Ti) particle stimulated macrophages.Methods: Peritoneal macrophages were stimulated with 1 × 109 Ti particles and treated simultaneously with or without 10, 100, or 1000 ng/mL Etanercept. The levels of TNF-α, IL-1β and IL-6 in the culture supernatants were measured using ELISA.Results: Titanium particles could stimulate TNF-α, IL-1β and IL-6 secretion in peritoneal macrophages. Etanercept inhibited Ti particle-induced TNF-α release by 29.7 % at 10 ng/ml (19.19 ± 4.72 pg/mL, p < 0.01), 49.3 % at 100 ng/mL (13.83 ± 3.72 pg/ml, p < 0.01) and 60.4 % at 1000 ng/mL (10.82 ± 3.87 pg/mL, p < 0.001), IL-1β release by 5.23 % at 10 ng/mL (34.79 ± 7.83 pg/mL, p > 0.05), 21.06 % at 100 ng/mL (28.98 ± 4.81 pg/mL, p < 0.01) and 29.83 % at 1000 ng/mL (25.76 ± 5.23 pg/ml, p < 0.001), and IL-6 release by 38.69 % at 10 ng/mL (256.8 ± 99.56 pg/mL, p < 0.01), by 42.13 % at 100 ng/mL (242.4 ± 33.26 pg/mL, p < 0.01) and 53.4 % at 1000 ng/ml (195.2 ± 48.82 pg/mL, p < 0.001).Conclusion: Etanercept has potent ability to prevent wear debris–induced osteolysis and may be valuable as a therapeutic agent for the treatment of prosthetic loosening in humans.Keywords: Etanercept; titanium particle; proinflammatory cytokines; peritoneal macrophage

    Forchheimer flow to a well-considering time-dependent critical radius

    Get PDF
    Previous studies on the non-Darcian flow into a pumping well assumed that critical radius (RCD) was a constant or infinity, where RCD represents the location of the interface between the non-Darcian flow region and Darcian flow region. In this study, a two-region model considering time-dependent RCD was established, where the non-Darcian flow was described by the Forchheimer equation. A new iteration method was proposed to estimate RCD based on the finite-difference method. The results showed that RCD increased with time until reaching the quasi steady-state flow, and the asymptotic value of RCD only depended on the critical specific discharge beyond which flow became non-Darcian. A larger inertial force would reduce the change rate of RCD with time, and resulted in a smaller RCD at a specific time during the transient flow. The difference between the new solution and previous solutions were obvious in the early pumping stage. The new solution agreed very well with the solution of the previous two-region model with a constant RCD under quasi steady flow. It agreed with the solution of the fully Darcian flow model in the Darcian flow region

    QUANTIFYING THE RELATIONSHIP BETWEEN NATURAL AND SOCIOECONOMIC FACTORS AND WITH FINE PARTICULATE MATTER (PM2.5) POLLUTION BY INTEGRATING REMOTE SENSING AND GEOSPATIAL BIG DATA

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    PM2.5 pollution is an environmental issue results from various natural and socioeconomic factors, frequently witnessed in the spring and winter across mainland China. However, the dominant influence of natural and socioeconomic factors within a city on PM2.5 is not extensively studied yet. In this study, the Random Forest Regression (RFR) is utilized to quantify the relationships between PM2.5 and potential factors within Wuhan city on a typical day turn from winter to spring. Technically, the 24-hour average PM2.5 concentration in downtown area on February 17th 2017 are collected at 9 sites. In the meantime, we retrieve simultaneous aerosol depth optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS). The ground measured PM2.5 and AOD are coupled for the retrieval of near-surface PM2.5 concentration by Spatial-temporal CoKriging (STCK) with Normalized Vegetation Index (NDVI), Modified Normalized Water Index (MNDWI), Normalized Building Index (NDBI) from Landsat-8 and DEM from Shuttle Radar Topography Mission (SRTM). As the geospatial big data booms, the Internet-collected volunteered geographic information (VGI), representing the urban form and function, are integrating for the regression to obtain the spatial variables importance measures (VIMs) by RFR both in centre and sub-urban region of Wuhan. The results reveal that terrain characteristics and the density of industrial enterprises have obvious relationships with the accumulation of PM2.5 while the density of roads also contributes to this

    Au plasmonics in a WS2-Au-CuInS2 photocatalyst for significantly enhanced hydrogen generation

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    Promoting the activities of photocatalysts is still the critical challenge in H2 generation area. Here, a Au plasmon enhanced photocatalyst of WS2-Au-CuInS2 is developed by inserting Au nanoparticles between WS2 nanotubes and CuInS2 (CIS) nanoparticles. Due to the localized surface plasmonic resonance properties from Au nanoparticles, WS2-Au-CIS shows the best performance as compared to Au-CIS, CIS, WS2-CIS, CIS-Au, WS2-Au, and WS2-CIS-Au. The surface plasmonic resonance effects dramatically intensify the absorption of visible light and help to inject hot electrons into the semiconductors. Our findings open up an efficient method to optimize the type-II structures for photocatalytic water splitting

    Obvious enhancement of the total reaction cross sections for 27,28^{27,28}P with 28^{28}Si target and the possible relavent mechanisms

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    The reaction cross sections of 27,28^{27,28}P and the corresponding isotones on Si target were measured at intermediate energies. The measured reaction cross sections of the N=12 and 13 isotones show an abrupt increase at % Z=15. The experimental results for the isotones with Z14Z\leq 14 as well as % ^{28}P can be well described by the modified Glauber theory of the optical limit approach. The enhancement of the reaction cross section for 28^{28}P could be explained in the modified Glauber theory with an enlarged core. Theoretical analysis with the modified Glauber theory of the optical limit and few-body approaches underpredicted the experimental data of 27^{27}P. Our theoretical analysis shows that an enlarged core together with proton halo are probably the mechanism responsible for the enhancement of the cross sections for the reaction of 27^{27}P+28^{28}Si.Comment: 16 pages, 5 figures, to be published in Phys.Rev.

    Receptor interactive protein kinase 3 promotes cisplatin-triggered necrosis in apoptosis-resistant esophageal squamous cell carcinoma cells

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    Cisplatin-based chemotherapy is currently the standard treatment for locally advanced esophageal cancer. Cisplatin has been shown to induce both apoptosis and necrosis in cancer cells, but the mechanism by which programmed necrosis is induced remains unknown. In this study, we provide evidence that cisplatin induces necrotic cell death in apoptosisresistant esophageal cancer cells. This cell death is dependent on RIPK3 and on necrosome formation via autocrine production of TNFα. More importantly, we demonstrate that RIPK3 is necessary for cisplatin-induced killing of esophageal cancer cells because inhibition of RIPK1 activity by necrostatin or knockdown of RIPK3 significantly attenuates necrosis and leads to cisplatin resistance. Moreover, microarray analysis confirmed an anti-apoptotic molecular expression pattern in esophageal cancer cells in response to cisplatin. Taken together, our data indicate that RIPK3 and autocrine production of TNFα contribute to cisplatin sensitivity by initiating necrosis when the apoptotic pathway is suppressed or absent in esophageal cancer cells. These data provide new insight into the molecular mechanisms underlying cisplatin-induced necrosis and suggest that RIPK3 is a potential marker for predicting cisplatin sensitivity in apoptosis-resistant and advanced esophageal cancer. © 2014 Xu et al

    The active fault belts in eastern Tibet margin inferred using magnetotellurics

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    A magnetotelluric (MT) sounding has been carried out in the eastern margin of the Tibetan plateau. The survey line is about 145 km long, trending in NEE direction and crossing the Daliangshan block in the eastern edge of the Tibetan plateau. The field measurements acquired effective data of 68 sites. Through data processing and a 2-D inversion with consideration of topography, a 2-D electrical structure model of crust and upper mantle was constructed. The structure reveals that there is a deep electrical boundary between the Daliangshan block in the west and Sichuan block in the east. West to the boundary, the crust has a relatively low resistivity with respect to the east and can be divided into three layers, the middle layer has low resistivity with a minimum of 3-10 W•m, presumably associated with partial melt and/or salty fluids. Beneath the intersection area of the Anninghe fault, the Xianshuihe fault and the Longmenshan fault, which the MT profile crosses, the faults are separated into upper and lower sections. The upper section exhibits a nearly vertical low-resistivity zone in the upper crust, and the lower section manifests an electrical boundary in the lower crust and upper mantle. Other faults in the Daliangshan block are either nearly vertical low-resistivity zones or electrical boundaries. It is suggested that the formation of the low-resistivity layer in the middle crust is associated with the southeastward motion of the eastern margin of the Tibetan plateau, clockwise rotation of the Chuandian (Sichuan-Yunnan) block, and the westward obstruction from the Sichuan block in Huanan terrain. Seismicity, including the M 8.0 Wenchuan earthquake in the study area, is discussed
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