Publications by authors named "Zhaoqiang Chen"

Microtextured microneedles are tiny needle-like structures with micron-scale microtextures, and the drugs stored in the microtextures can be released after entering the skin to achieve the effect of precise drug delivery. In this study, the skin substitution model of Ogden's hyperelastic model and the microneedle array and microtexture models with different geometrical parameters were selected to simulate and analyse the flow of the microtexture microneedle arrays penetrating the skin by the finite-element method, and the length of the microneedles was determined to be 200 μm, the width 160 μm, and the value of the gaps was determined to be 420 μm. A four-pronged cone was chosen as the shape of microneedles, and a rectangle was chosen as the shape of the drug-carrying microneedle.

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An efficient dehydrative coupling of propargylic alcohols with diarylphosphine oxides to construct tetrasubstituted allenylphosphoryl compounds in the presence of a Pd/Brønsted acid co-catalyst has been developed. As a benefit from the use of a Brønsted acid, this reaction could perform under mild conditions with excellent yields, accommodating a wide range of functional groups. The potential utility of this method has also been demonstrated.

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To investigate the impact of interfacial layer effects on the thermal conductivity of nanofluids and the microscopic mechanisms of enhanced thermal conductivity, this study employed non-equilibrium molecular dynamics to compute the thermal conductivity, number density, radial distribution function, and mean square displacement distribution of SiC nanofluids. The impact of nanoparticle volume fraction and particle size parameters on the thermal conductivity of nanofluids and the structure of interfacial adsorption layers was discussed. The simulation calculation results show that the coefficient of thermal conductivity of nanofluid is positively related to the volume fraction of nanoparticles, increasing from 0.

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Aiming at the difficulty of traditional machining of YO-ZrO (YSZ) inert ceramic materials, a different method using focused ion beam to selectively create nanoscale microscale structures on the surface of materials was proposed. The sputtering yield, surface damage, and the energy loss of YSZ materials was investigated using the SRIM software using the Monte Carlo method. It is shown that the sputtering yield increases with ion energy in the range 0-30 keV, reaching a maximum of 9.

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Background: Ginsenoside compound K (CK), the main active metabolite in , has shown good safety and bioavailability in clinical trials and exerts neuroprotective effects in cerebral ischemic stroke. However, its potential role in the prevention of cerebral ischemia/reperfusion (I/R) injury remains unclear. Our study aimed to investigate the molecular mechanism of ginsenoside CK against cerebral I/R injury.

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Cutting force in lathe work is closely related to tool wear and affects the turning quality. Direct measurement of the cutting force by measuring the strain of the tool holder is challenging because the tool holder design aims to be highly rigid in order to undertake large cutting forces. Accordingly, the most popular dynamometer designs modify the standard tool holder by decreasing the structural rigidity of the holder, which reduces the machining precision and is not widely accepted.

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Background: Respiratory diseases mainly include asthma, influenza, pneumonia, chronic obstructive pulmonary disease, pulmonary hypertension, lung fibrosis, and lung cancer. Given their high prevalence and poor prognosis, the prevention and treatment of respiratory diseases are increasingly essential. In particular, the development for the novel strategies of drug treatment has been a hot topic in the research field.

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The addition of CaF@SiO and SiC whiskers to ceramic tools can improve their flexural strength and fracture toughness, reduce surface damage, and improve their cutting performance. The cutting experiments showed that under the same cutting conditions, the surface roughness of the workpiece processed with the AlO/TiC/SiC/CaF@SiO (ATSC10) tool was significantly lower than that of the workpiece processed with the AlO/TiC/ SiC (ATS) tool. Additionally, the main cutting force and cutting temperature when cutting with the ATSC10 tool were lower by 30 and 31.

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Panax ginseng, as the king of Chinese herb, has significant therapeutic effects on obesity, type 2 diabetes mellitus, fatty liver disease, colitis, diarrhea, and many other diseases. This review systematically summarized recent findings, which show that ginseng plays its role by regulating gut microbiota diversity, and gut microbiota could also regulate the transformation of ginsenosides. We conclude the characteristics of ginseng in regulating gut microbiota, as the potential targets to prevent and treat metabolic diseases, colitis, neurological diseases, cancer, and other diseases.

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Background: Knowledge of protein motions is significant to understand its functions. While currently available databases for protein motions are mostly focused on overall domain motions, little attention is paid on local residue motions. Albeit with relatively small scale, the local residue motions, especially those residues in binding pockets, may play crucial roles in protein functioning and ligands binding.

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Cutting heat conduction undergoes three stages that include intensity transient-state, transient-state, and steady-states. Especially during machining with coated cutting tools, in the conduction process, cutting heat needs to pass through a few micron thick coatings and then flow into the tool body. This heat conduction presents typical non-Fourier heat conduction characteristics.

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Alzheimer's disease (AD), a neurodegenerative disorder, is a major health concern in the increasingly aged population worldwide. Currently, no clinically effective drug can halt the progression of AD. C.

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In this paper, the Voronoimosaic model and the cohesive element method were used to simulate crack propagation in the microstructure of alumina/graphene composite ceramic tool materials. The effects of graphene characteristic size and volume content on the crack propagation behavior of microstructure model of alumina/graphene composite ceramics under different interfacial bonding strength were studied. When the phase interface is weak, the average energy release rate is the highest as the short diameter of graphene is 10-50 nm and the long diameter is 1600-2000 nm.

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The substitution of methyl (Me or -CH) by trifluoromethyl (TFM or -CF) is frequently used in medicinal chemistry. However, the exact effect of -CH/-CF substitution on bioactivity is still controversial. We compiled a data set containing 28 003 pairs of compounds with the only difference that -CH is substituted by -CF, and the statistical results showed that the replacement of -CH with -CF does not improve bioactivity on average.

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Halogen bonding (XB) has been applied in many fields from crystal engineering to medicinal chemistry. Compared with the well-studied XB of simple halogenated aromatics, little research has been done on the XB of halogenated fused-ring heteroaromatics, a prevalent substructure in organic compounds. With 1H-pyrrolo[3,2-b]pyridines (PPs) as examples of novel fused-ring heteroaromatics with hydrogen bond donor and acceptor and XB donor, the XB formed by the halogenated heteroaromatics was explored in this study.

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This study aimed at improving the cutting performance of a ceramic tool to which were added solid lubricant particles. We prepared the self-lubricating ceramic tool by adding CaF@AlO instead of CaF, and the self-lubricating ceramic tool with AlO as matrix phase, Ti(C,N) as reinforcement phase. The properties of the ceramic tool with different contents of CaF@AlO and CaF were studied by turning 40Cr.

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Eight bisindole alkaloids including six undescribed ones (1a/1b-5) were isolated from an alcohol extract of the Isatis indigotica roots. Their structures and absolute configurations were supported by extensive spectroscopic data analysis, including 1D, 2D NMR, HRESIMS data, specific rotation data, and comparison of the experimental and calculated ECD data. Compounds 1a and 1b were determined to be a pair of enantiomers with a ratio of approximately 1:1 by chiral-phase chromatography analysis while compound 4 was elucidated as a new type of bisindole alkaloid with the aglycone categorized as bis(indole-1'/3″-yl)methane.

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Four undescribed sulfur-containing indole alkaloids, isatisindigoticanines H, I and isatindigosides F, G along with three known analogues were obtained from Isatis tinctoria L. roots. Isatisindigoticanines H and I contained an unusual 1-(thiazol-4-yl)butane-1,2,3,4-tetraol moiety while isatindigosides F and G possessed a new 3-[3-(1H-indole-2-yl)azet-2-yl]-1H-indole skeleton.

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Replica exchange molecular dynamics (REMD) simulation is a popular enhanced sampling method that is widely used for exploring the atomic mechanism of protein conformational change. However, the requirement of huge computational resources for REMD, especially with the explicit solvent model, largely limits its application. In this study, the availability and efficiency of a variant of velocity-scaling REMD (vsREMD) was assessed with adenylate kinase as an example.

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The enoyl-acyl carrier protein reductase InhA of is an attractive, validated target for antituberculosis drug development. Moreover, direct inhibitors of InhA remain effective against InhA variants with mutations associated with isoniazid resistance, offering the potential for activity against MDR isolates. Here, structure-based virtual screening supported by biological assays was applied to identify novel InhA inhibitors as potential antituberculosis agents.

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Aiming at the contradiction between the lubricating performance and mechanical performance of self-lubricating ceramic tools. CaF@Al(OH) particles were prepared by the heterogeneous nucleation method. An AlO/Ti(C,N) ceramic tool with CaF@Al(OH) particles and ZrO whiskers was prepared by hot press sintering (frittage).

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In order to reduce the influence of CaF addition on the mechanical properties of self-lubricating ceramic tools, we applied a silicon dioxide (SiO) coating on calcium fluoride (CaF) nanoparticles through hydrolysis and condensation reactions using the tetraethoxysilane (TEOS) method. The powder was dried by the azeotropic method, so that it acquired a better dispersibility. The resulting composite powders were characterized using XRD (X-ray diffraction) and TEM (transmission electron microscopy), showing that the surface of CaF was coated with a layer of uniform and compact SiO.

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