2,163 research outputs found

    On the shock wave boundary layer interaction in slightly-rarefied gas

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    The shock wave and boundary layer interaction (SWBLI) plays an important role in the design of hypersonic vehicles. However, discrepancies between the numerical results of high-temperature gas dynamics and experiment data have not been fully addressed. It is believed that the rarefaction effects are important in SWBLI, but the systematic analysis of the temperature-jump boundary conditions and the role of translational/rotational/vibrational heat conductivities are lacking. In this paper, we derive the three-temperature Navier-Stokes-Fourier (NSF) equations from the gas kinetic theory, with special attention paid to the components of heat conductivity. With proper temperature-jump boundary conditions, we simulate the SWBLI in the double cone experiment. Our numerical results show that, when the three heat conductivities are properly recovered, the NSF equations can capture the position and peak value of the surface heat flux, in both low- and high-enthalpy inflow conditions. Moreover, the separation bubble induced by the separated shock and the reattachment point induced by impact between transmitted shock and boundary layer are found to agree with the experimental measurement

    Electrolysis of metal oxides in MgCl2 based molten salts with an inert graphite anode

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    Eletrolysis of solid metal oxides has been demonstrated in MgCl2-NaCl-KCl melt at 700 oC taking the electrolysis of Ta2O5 as an example. Both the cathodic and anodic processes have been investigated using cyclic voltammetry, potentiostatic and constant voltage electrolysis, with the cathodic products analysed by XRD, SEM and the anodic products by GC. Fast electrolysis of Ta2O5 against a graphite anode has been realized at a cell voltage of 2 V , or a total overpotential of about 400 mV. The energy consumption was about 1 kWh/kg-Ta with a nearly 100% Ta recovery. The cathodic product was nanometer Ta powder with sizes of about 50 nm. The main anodic product was Cl2 gas, together with about 1 mol% O2 gas and trace of CO. The graphite anode was found to be an excellent inert anode. These results promise an environment-friendly and energy efficient method for metal extraction by electrolysis of metal oxides in MgCl2 based molten salts

    The regulatory effects of second-generation antipsychotics on lipid metabolism: Potential mechanisms mediated by the gut microbiota and therapeutic implications

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    Second-generation antipsychotics (SGAs) are the mainstay of treatment for schizophrenia and other neuropsychiatric diseases but cause a high risk of disruption to lipid metabolism, which is an intractable therapeutic challenge worldwide. Although the exact mechanisms underlying this lipid disturbance are complex, an increasing body of evidence has suggested the involvement of the gut microbiota in SGA-induced lipid dysregulation since SGA treatment may alter the abundance and composition of the intestinal microflora. The subsequent effects involve the generation of different categories of signaling molecules by gut microbes such as endogenous cannabinoids, cholesterol, short-chain fatty acids (SCFAs), bile acids (BAs), and gut hormones that regulate lipid metabolism. On the one hand, these signaling molecules can directly activate the vagus nerve or be transported into the brain to influence appetite via the gut–brain axis. On the other hand, these molecules can also regulate related lipid metabolism via peripheral signaling pathways. Interestingly, therapeutic strategies directly targeting the gut microbiota and related metabolites seem to have promising efficacy in the treatment of SGA-induced lipid disturbances. Thus, this review provides a comprehensive understanding of how SGAs can induce disturbances in lipid metabolism by altering the gut microbiota

    Enhanced Crystallinity of Triple-Cation Perovskite Film via Doping NH\u3csub\u3e4\u3c/sub\u3eSCN

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    The trap-state density in perovskite films largely determines the photovoltaic performance of perovskite solar cells (PSCs). Increasing the crystal grain size in perovskite films is an effective method to reduce the trap-state density. Here, we have added NH4SCN into perovskite precursor solution to obtain perovskite films with an increased crystal grain size. The perovskite with increased crystal grain size shows a much lower trap-state density compared with reference perovskite films, resulting in an improved photovoltaic performance in PSCs. The champion photovoltaic device has achieved a power conversion efficiency of 19.36%. The proposed method may also impact other optoelectronic devices based on perovskite films

    Machine learning-based identification of tumor-infiltrating immune cell-associated model with appealing implications in improving prognosis and immunotherapy response in bladder cancer patients

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    BackgroundImmune cells are crucial components of the tumor microenvironment (TME) and regulate cancer cell development. Nevertheless, the clinical implications of immune cell infiltration-related mRNAs for bladder cancer (BCa) are still unclear.MethodsA 10-fold cross-validation framework with 101 combinations of 10 machine-learning algorithms was employed to develop a consensus immune cell infiltration-related signature (IRS). The predictive performance of IRS in terms of prognosis and immunotherapy was comprehensively evaluated.ResultsThe IRS demonstrated high accuracy and stable performance in prognosis prediction across multiple datasets including TCGA-BLCA, eight independent GEO datasets, our in-house cohort (PUMCH_Uro), and thirteen immune checkpoint inhibitors (ICIs) cohorts. Additionally, IRS was superior to traditional clinicopathological features (e.g., stage and grade) and 94 published signatures. Furthermore, IRS was an independent risk factor for overall survival in TCGA-BLCA and several GEO datasets, and for recurrence-free survival in PUMCH_Uro. In the PUMCH_Uro cohort, patients in the high-IRS group were characterized by upregulated CD8A and PD-L1 and TME of inflamed and immunosuppressive phenotypes. As predicted, these patients should benefit from ICI therapy and chemotherapy. Furthermore, in the ICI cohorts, the high-IRS group was related to a favorable prognosis and responders have dramatically higher IRS compared to non-responders.ConclusionsGenerally, these indicators suggested the promising application of IRS in urological practices for the early identification of high-risk patients and potential candidates for ICI application to prolong the survival of individual BCa patients

    Influences of graphite anode area on electrolysis of solid metal oxides in molten salts

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    Laboratory studies of electrochemical reduction of refractory metal oxides, e.g. TiO2 and Ta2O5, in molten CaCl2 often involve a graphite anode and a cell voltage of 3.0 V or higher, which deviates significantly from thermodynamic predictions. The causes considered in the past have included mechanistic, kinetic and dynamic complications of cathode reactions, but little was considered on anodic processes. This paper shows that oxidation of the O2− ion on the graphite anode is also a significant contributor to the high cell voltages applied. Cyclic voltammetry in molten CaCl2 containing added CaO (up to 2.51 mol%) suggested that O2− oxidation on graphite proceeds dominantly in two steps as previously observed on glassy carbon. With increasing CaO concentration, the second step became rate-limiting over a wide range of potentials before the processes reached at diffusion controlled high current density. This understanding led to the proposal and experimental confirmation of a “low anode current density strategy” in potentiostatic reduction of thin cylindrical pellets of TiO2 and Ta2O5 in molten CaCl2 at 850 °C. It was observed that a 10-fold increase of the graphite anode area could decrease the cell voltage by about 1.0 V, which should save energy consumption by up to one third

    Environmental and energy gains from using molten magnesium-sodium-potassium chlorides for electro-metallisation of refractory metal oxides

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    © 2015 The Authors. The molten eutectic mixture of magnesium, sodium and potassium chlorides (MgCl2-NaCl-KCl) has inappreciable solubility for oxide ions, and can help disengage a carbon anode from the oxide ions generated at a metal oxide cathode, and effectively avoid carbon dioxide formation. This "disengaging strategy" was successfully demonstrated in electro-reduction of solid oxides of zirconium and tantalum. It has led to significantly higher current efficiency (93%), and lower energy consumption (1.4 kW h kg-1) in electrolysis of tantalum oxide to tantalum metal compared to the conventional electrolysis in molten calcium chloride (e.g. 78% and 2.4 kW h/kg-Ta)

    Leveraging a disulfidptosis-based signature to improve the survival and drug sensitivity of bladder cancer patients

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    BackgroundDisulfidptosis is a recently discovered form of cell death. However, its biological mechanisms in bladder cancer (BCa) are yet to be understood.MethodsDisulfidptosis-related clusters were identified by consensus clustering. A disulfidptosis-related gene (DRG) prognostic model was established and verified in various datasets. A series of experiments including qRT-PCR, immunoblotting, IHC, CCK-8, EdU, wound-healing, transwell, dual-luciferase reporter, and ChIP assays were used to study the biological functions.ResultsWe identified two DRG clusters, which exhibited distinct clinicopathological features, prognosis, and tumor immune microenvironment (TIME) landscapes. A DRG prognostic model with ten features (DCBLD2, JAM3, CSPG4, SCEL, GOLGA8A, CNTN1, APLP1, PTPRR, POU5F1, CTSE) was established and verified in several external datasets in terms of prognosis and immunotherapy response prediction. BCa patients with high DRG scores may be characterized by declined survival, inflamed TIME, and elevated tumor mutation burden. Besides, the correlation between DRG score and immune checkpoint genes and chemoradiotherapy-related genes indicated the implication of the model in personalized therapy. Furthermore, random survival forest analysis was performed to select the top important features within the model: POU5F1 and CTSE. qRT-PCR, immunoblotting, and immunohistochemistry assays showed the enhanced expression of CTSE in BCa tumor tissues. A series of phenotypic assays revealed the oncogenetic roles of CTSE in BCa cells. Mechanically, POU5F1 can transactivate CTSE, promoting BCa cell proliferation and metastasis.ConclusionsOur study highlighted the disulfidptosis in the regulation of tumor progression, sensitivity to therapy, and survival of BCa patients. POU5F1 and CTSE may be potential therapeutic targets for the clinical treatment of BCa
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