Photocatalysis-assisted chemical mechanical polishing, in which the photocatalysis oxidation and silica abrasives polishing are combined, is a novel finishing technique for 4H–SiC wafer. This paper ...characterizes the effect of pressure and abrasives on the MRR and surface quality and discusses mechanical and chemical interaction based three slurries that resulted in maximum material removal rate (1.18 μm/h) with PCMP slurry. The polished silicon carbide wafer was examined with atomic force microscope, transmission electron microscope and X-ray photoelectron spectroscopy for surface quality and material removal mechanism. The results show that an atomically smooth and flat 4H–SiC (0001) surface (Ra about 0.247 nm) was obtained by PCMP. The interface of crystal and amorphous layer of 4H–SiC wafer was flat without introducing crystallographic subsurface damage, and the atoms and lattice fringes of the crystal layer are arranged in regular order. The existence of a thin silicon oxycarbide layer, which are various forms of functional groups such as Si–C, Si–C–O, Si–O, Si
4
C
4
O
4
, C–O, and C = O, at the interface. And, it also demonstrates that the amorphous layer is composed of oxide layer (4–6 nm) and distorted layer. The silicon carbide surface is mechanically activated, oxidized and mechanically removed in turn, which is the main method of material removal.
The "missing" link of complex and multifaceted interplay among endogenous retroviruses (ERVs) transcription, chronic immuno-inflammation, and the development of psychiatric disorders is still far ...from being completely clarified. The present study was aimed to investigate the mechanism of protective role of inhibiting ERVs on reversing microglial immuno-inflammation in basolateral amygdala (BLA) in chronic stress-induced negative emotional behaviors in mice.
Male C57BL/6 mice were exposed to chronic unpredictable mild stress (CUMS) for 6 w. Negative emotional behaviors were comprehensively investigated to identify the susceptible mice. Microglial morphology, ERVs transcription, intrinsic nucleic acids sensing response, and immuno-inflammation in BLA were assessed.
Mice with chronic stress were presented as obviously depressive- and anxiety-like behaviors, and accompanied with significant microglial morphological activation, murine ERVs genes MuERV-L, MusD, and IAP transcription, cGAS-IFI16-STING pathway activation, NF-κB signaling pathway priming, as well as NLRP3 inflammasome activation in BLA. Antiretroviral therapy, pharmacological inhibition of reverse transcriptases, as well as knocking-down the ERVs transcriptional regulation gene p53 significantly inhibited microglial ERVs transcription and immuno-inflammation in BLA, as well as improved the chronic stress-induced negative emotional behaviors.
Our results provided an innovative therapeutic approach that targeting ERVs-associated microglial immuno-inflammation may be beneficial to the patients with psychotic disorders.
Loss of podocytes is a hallmark of diabetic nephropathy, and a growing body of evidence indicates that podocytes are susceptible to palmitic acid (PA). We have previously shown that AS-IV inhibited ...PA-induced podocyte apoptosis by activating sarcoendoplasmic reticulum Ca
2+
ATPase (SERCA), which indicate calcium regulation may involve in the process. Immunofluorescence staining, Western blot and flow cytometry were used to measure the protective efficacy of AS-IV to ameliorate PA-induced ER stress and podocyte apoptosis. Meanwhile, AS-IV inhibited cytochrome c release, decreased mitochondrial membrane potential, accompany with the depletion of endoplasmic reticulum Ca
2+
and elevation of cytosolic and mitochondrial Ca
2+
. Sequestration of cytosolic calcium with BAPTA-AM limited the response of podocyte apoptosis, while during the process the effect of AS-IV was also restrained. In contrast, elevation of cytosolic calcium with calcium ionophore ionomycin was depressed by AS-IV addition. Furthermore, inhibiting TRPC6 expression with SKF96365 or TRPC6 siRNA counteracted the beneficial effect of AS-IV. Our study provides further evidence to conclude the inhibitory effect of AS-IV to podocyte apoptosis is Ca
2+
-dependent. And the efficacy correlates with inhibiting TRPC6-mediated Ca
2+
influx, and then cellular Ca
2+
disturbance was coordinated.
N6-methyladenosine (m6A) modification is the most universal and abundant post-transcriptional modification of eukaryotic RNA and occurs mainly at the consensus motif RR (m6A) CH (R = A or G, H = A, ...C, or U) in long internal exons, near stop codons, or in the 3' untranslated region (UTR). "Writers," "erasers," and "readers" are responsible for the occurrence, removal, and recognition of m6A modification, respectively. Substantial evidence has shown that m6A RNA modification can exert important functions in physiological and pathological processes. Cardiovascular diseases (CVDs) are a wide array of disorders affecting heart or vessels, including atherosclerosis (AS), hypertension (HT), ischemia/reperfusion (I/R) injury, myocardial infarction (MI), stroke, cardiac hypertrophy, heart failure (HF), and so on. Despite the advances in lipid-lowering drugs, antihypertensives, antiplatelet agents, and anticoagulation therapy, CVDs are still the leading cause of death worldwide. Recent studies have suggested that m6A modification of RNA may contribute to the pathogenesis of CVDs, providing a novel research insight for CVDs. Herein, we provide an up-of-date summarization of the molecular mechanism of m6A and the roles of m6A in different types of CVDs. At last, we propose that m6A might be a potiential biomarker or therapeutic target for CVDs.
The efficient and flexible conversion of electrical energy is increasingly accomplished by megawatt insulated gate bipolar transistor (IGBT) modules. Their dynamic performance is influenced by the ...gate driver control, operating points and the switching loop parasitics, which are crucial to their optimized operational behaviours, efficiency and field reliability. This paper investigates the controllability of the transient voltage and current slopes of megawatt IGBT modules during their turn‐off transitions and proposes an efficient assessment method accordingly. Firstly, the causal relationship of transient characteristic variations and controllability is investigated analytically. Then, major factors impacting the controllability are analysed and validated, including the charge carrier profile, the operating points (i.e. the load voltage, the load current, and the junction temperature), and the gate resistance. Finally, an efficient method using the MOS‐channel turn‐off point on calibrated gate voltage waveform is proposed for the controllability evaluation, which can guide the IGBT, gate driver, and converter design.
A cesium/oxygen activation experiment was conducted on a gallium-arsenide-based electron-injection cathode in an ultra-high vacuum system connected to a spectral response measuring instrument. Before ...activation, high-temperature cleaning was performed at 650 °C to obtain an atomically clean surface. The cathode surface impurities before and after the experiment were characterized by X-ray photoelectron spectroscopy. Because of the cathode Ti/Pt/Au electrode properties, the sample could not be cleaned chemically. High-temperature cathode treatment before activation could not remove the oxides completely, which led to a low cathode emission capacity in the photocurrent and spectral response. The experimental quantum efficiency curve was fitted by a two-minima diffusion model, and parameters, such as the electron diffusion length and escape probability, which characterize the cathode performance, were calculated. According to the fitting results, the residual impurities on the cathode surface and the thin emitter layer resulted in a low probability of electron escape, which resulted in a low quantum efficiency.
•The cesium/oxygen activation experiment and XPS analysis of GaAs-based electron-injected cathode were conducted.•A series of electron-injected cathode performance parameters was obtained by fitting the experimental curves.•A low probability of electron escape is attributed to the cleaning process of electron-injection cathode.
Self-healable hydrogels have attracted significant interests in the fields of environmental protection, oil plugging and electronic sensors, etc. Benefiting from the synergistic contribution of ...hydrogen bonding and ligand chelation, in this work, we prepared a series of self-healable hydrogels via a simple and inexpensive approach, which overcame the limitations of the intrinsic nature of dynamic covalent bonds and non-covalent interactions under harsh conditions. Systematic study of the effect of temperature, salt concentration and particle size on the physicochemical performance of the re-crosslinking progress revealed that re-crosslinked gels using particles of 0.20–0.28 mm (in a solution with salt concentration of 10%) at 130 °C presented an elastic modulus of 62 Pa at a frequency of 10 Hz and remained elastic after 45 days of aging (elastic modulus: 18,170 Pa). Of particular interest, gel particles with a particle size of 0.125–0.28 mm can be reassembled at temperatures up to 150 °C or salt concentrations up to 20%, which is superior to a plethora of previous reports (self-healing temperature usually less than 130 °C, salt concentration <10%). Employment of the green inexpensive sodium D-gluconate instead of partial acrylamide makes the gel product a promising candidate material for oil plugging, targeting fractured reservoirs for consistent control.
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•Self-healable hydrogels were fabricated in a simple and inexpensive method.•Hydrogels were capable of re-crosslinking at harsh conditions.•Chelation of metal ions and hydrogen bonds contributed to the re-crosslinking process.•This re-crosslinkable hydrogel is a promising candidate for oil plugging.
•The cathode uses an electrical signal instead of laser for electron injection.•Extending the cathode lifetime and eliminating the harmful emission.•Inhibiting the hole current and increasing the ...emission current efficiency.
The electron emission model of a negative electron affinity graded-bandgap AlGaAs/GaAs electron-injection cathode was developed from two-dimensional continuity equations. The emission current was obtained from a simulation of the model, and the emission current efficiency and emission current per unit length were calculated. Based on the simulation results and preparation conditions, the range of optimum parameters for the cathode structure were determined. The ranges of optimum thickness for the p-AlGaAs and the graded-bandgap p-AlGaAs layers were 0.05–0.15 μm and 0.1–0.3 μm, respectively. The optimum width of the base electrode ranged from 1 to 4 μm, and the optimum molar ratios of Al in the p-AlGaAs and the n-AlGaAs layers were 0.2–0.3 and 0.4–0.5, respectively. This abrupt PN heterojunction inhibited the hole current and increased the emission current efficiency, with a maximum value of 25.3%. According to the emission current per unit length, the optimum range of width of emission unit surface was 6 to 10 μm, and the peak emission current per unit length reached 43.2 μA/μm.
To investigate the biotransformation of daphnetin by suspension transgenic hairy root of Polygonum multiflorum and provide a biotechnological method for large-scale production of the ...daphnetin-8-O-beta-D-glucoside using this new culture system.
Daphnetin was added into the media of suspension to culture 36 h. The biotransformation product was detected with TLC and HPLC, and isolated by various chromatographic methods. The influence of co-cultured time on conversion ratio, content of degradation product and the reason for the degradation of product II were investigated using HPLC.
One biotransformation product, daphnetin-8-O-beta-D-glucoside, was obtained, the optimal co-cultured time in suspension hairy root of P. multiflorum was 36 h with the highest biotransformation molar ratio of 32.11%, the sucrose medium (sucrose-only) can increase the biotransformation molar ratio to 72.44%. The result demonstrated that the degradation products of the product II was induced by the MS medium.
The potential application of suspension transgenic hairy root of P. multflorum in the sucrose-only medium on generating daphnetin-8-Obeta-D- glucoside could be prospective.
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