Plasmon-gating photoluminescence in graphene/GeSi quantum dots hybrid structures

The ability to control light-matter interaction is central to several potential applications in lasing, sensing, and communication. Graphene plasmons provide a way of strongly enhancing the interaction and realizing ultrathin optoelectronic devices. Here, we find that photoluminescence (PL) intensities of the graphene/GeSi quantum dots hybrid structures are saturated and quenched under positive and negative voltages at the excitation of 325 nm, respectively. A mechanism called plasmon-gating effect is proposed to reveal the PL dependence of the hybrid structures on the external electric field. On the contrary, the PL intensities at the excitation of 405 and 795 nm of the hybrid structures are quenched due to the charge transfer by tuning the Fermi level of graphene or the blocking of the excitons recombination by excitons separation effect. The results also provide an evidence for the charge transfer mechanism. The plasmon gating effect on the PL provides a new way to control the optical properties of graphene/QD hybrid structures

Layer-dependent nanoscale electrical properties of graphene studied by conductive scanning probe microscopy

Abstract The nanoscale electrical properties of single-layer graphene (SLG), bilayer graphene (BLG) and multilayer graphene (MLG) are studied by scanning capacitance microscopy (SCM) and electrostatic force microscopy (EFM). The quantum capacitance of graphene deduced from SCM results is found to increase with the layer number (n) at the sample bias of 0 V but decreases with n at -3 V. Furthermore, the quantum capacitance increases very rapidly with the gate voltage for SLG, but this increase is much slowed down when n becomes greater. On the other hand, the magnitude of the EFM phase shift with respect to the SiO2 substrate increases with n at the sample bias of +2 V but decreases with n at -2 V. The difference in both quantum capacitance and EFM phase shift is significant between SLG and BLG but becomes much weaker between MLGs with a different n. The layer-dependent quantum capacitance behaviors of graphene could be attributed to their layer-dependent electronic structure as well as the layer-varied dependence on gate voltage, while the layer-dependent EFM phase shift is caused by not only the layer-dependent surface potential but also the layer-dependent capacitance derivation.</p

CFD simulation of gas-liquid flow in stirred tanks: Effect of drag models

Drag force plays important roles in the prediction of gas-liquid flow in stirred tanks, but systematic studies on drag models are still lacking. In this study, we evaluated the effect of four different drag models (DBS-Local, DBS-Global, Brucato, Schiller-Naumann) in which the DBS model was originally developed for bubble columns. The flow regime, liquid flow field and gas holdup predicted by the four drag models are compared with experiments. The DBS-Local and DBS-Global models show the advantages over the other two in the prediction of gas dispersion and flow structure, since the ratio of effective drag coefficient to bubble diameter is either one or twoorders of magnitude over-estimated by the Brucato model or under-predicted by the Schiller-Naumann model. The flow regime at different rotational speeds and the effects of gas dispersion on the liquid loop structure can be correctly predicted by the DBS drag models. This study demonstrates that the drag model is extremely important to accurately predict the gas-liquid flow in stirred tanks

CFD Simulation of Gas Dispersion in a Stirred Tank of Dual Rushton Turbines

3D Eulerian-Eulerian model was applied to simulate the gas-liquid two-phase flow in a stirred tank of dual Rushton turbines using computational fluid dynamics (CFD). The effects of two different bubble treatment methods (constant bubble size vs. population balance model, PBM) and two different coalescence models (Luo model vs. Zaichik model) on the prediction of liquid flow field, local gas holdup or bubble size distribution were studied. The results indicate that there is less difference between the predictions of liquid flow field and gas holdup using the above models, and the use of PBM did not show any advantage over the constant bubble size model under lower gas holdup. However, bubble treatment methods have great influence on the local gas holdup under larger gas flow rate. All the models could reasonably predict the gas holdup distribution in the tank operated at a low aeration rate except the region far from the shaft. Different coalescence models have great influence on the prediction of bubble size distribution (BSD). Both the Luo model and Zaichik model could qualitatively estimate the BSD, showing the turning points near the impellers along the height, but the quantitative agreement with experiments is not achieved. The former over-predicts the BSD and the latter under-predicts, showing that the existing PBM models need to be further developed to incorporate more physics.</p

Tiaolipiwei Acupuncture Reduces Albuminuria by Alleviating Podocyte Lesions in a Rat Model of Diabetic Nephropathy

Background. Diabetic nephropathy is a common and serious complication of diabetes and a major cause of end-stage renal disease. Tiaolipiwei acupuncture is a safe treatment approach that may be effective for lowering albuminuria in diabetic nephropathy. Yet, the exact mechanisms of this therapeutic effect are unclear. Methods. A rodent model of type 2 diabetic nephropathy (T2DN) was induced by a high-fat diet combined with low-dose streptozotocin. T2DN rats were treated with Tiaolipiwei acupuncture (ACU) for 4, 8, or 12 weeks. At the end of treatment, urinary and blood samples were collected for analysis. Transmission electron microscopy was used to observe morphological changes, and protein expression levels of nephrin, CD2AP, podocalyxin, and desmin were quantified in renal tissue. Results. Compared to the T2DN groups, the T2DN + ACU groups showed significant improvements in 24-hour urinary protein, serum urea, cholesterol, and triglycerides at all time points. ACU treatment also improved the density of slit diaphragms. Simultaneously, ACU promoted the renal expression of nephrin, CD2AP, and podocalyxin and decreased the expression of desmin. Conclusion. Our study suggests that Tiaolipiwei acupuncture ameliorates podocyte lesions to reduce albuminuria and prevent the progression of T2DN in a rat model

Efficacy and safety of fire-needle in the treatment of gouty arthritis： a protocol for systematic review and meta analysis

Background Fire needle therapy is an ancient external treatment method of traditional Chinese medicine. This therapy is simple to operate and has fewer side effects. Gouty arthritis is common disease that is often characterized by high excruciating pain on joint. Evidence from clinical studies show that fire needle exert therapeutic effects on gout arthritis, but no evidence-based medicine is available. This study aimed to evaluate the efficacy and safety of fire acupuncture in the treatment of gout arthritis. Methods Randomized controlled trials (RCTs) of fire needle in the treatment of GA published until May，2020 will be searched in the English databases (PubMed, EMBASE, web of science, the Cochrane Library）and Chinese databases (China National Knowledge Infrastructure, the Chongqing VIP Chinese Science and Technology Periodical Database, Wanfang database, and China biomedical literature database). Additional search will be performed on Google academy and Baidu Academy. Data will be extracted from the studies by two reviewers working independently. Subsequently, quality assessment and a meta-analysis will be carried out for the studies using RevMan 5.3. Results The efficacy and safety of fire needle in the treatment of GA will be evaluated based on overall effective rate, VAS, BUA, CRP, joint swelling and pain score, adverse reaction rate, and other clinical outcomes. Conclusions The proposed systematic review and meta-analysis are expected to provide reliable evidence for the clinical benefits of fire-needle therapy in GA

Enhanced IL-10 inhibits proliferation and promotes apoptosis of HUVECs through STAT3 signaling pathway in sepsis

Aims. The present study aims to determine the expression of interleukin (IL)-10 in peripheral blood of patients with sepsis, and investigate its effects on the biological function of vascular endothelial cells. Methods. Thirty-six sepsis patients and 20 healthy subjects were included. Peripheral blood was collected from all subjects. ELISA was used to determine IL-10 content in serum. A ratio of IL-10+ T cells was determined by flow cytometry. CCK-8 assay was used to investigate proliferation. Cell cycle and apoptosis were analyzed by flow cytometry. Western blotting was used to examine the expression of phosphorylated STAT3 protein. Results. The content of IL-10 and the ratio of IL-10+ T cells were enhanced in pa-tients with sepsis. Serum from patients with sepsis inhibited the proliferation of HU-VECs, and addition of IL-10 antibody reversed this effect. IL-10 in the serum from patients with sepsis promoted the apoptosis of HUVECs. IL-10 inhibited the proliferation and promoted the apoptosis of HUVECs by enhancing the phosphorylation of STAT3. Conclusions. The present study demonstrates that the content of IL-10 and the ratio of IL-10+ T cells in peripheral blood of patients with sepsis are up-regulated, and this inhibits HUVEC proliferation and promotes HUVEC apoptosis through STAT3 sig-naling pathway. The results in this study provide a new experimental basis for further understanding the molecular mechanism of sepsis-induced vascular injury