Mas‐related G protein‐coupled receptor X2 was a mast cell–specific receptor mediating anaphylactoid reactions by activating mast cells degranulation, and it was also identified as a target for modulating mast cell–mediated anaphylactoid and inflammatory diseases. The anti‐anaphylactoid drugs used clinically disturb the partial effect of partial mediators released by mast cells. The small molecule of Mas‐related G protein‐coupled receptor X2 specific antagonists may provide therapeutic action for the anaphylactoid and inflammatory diseases in the early stage. In this study, the Mas‐related G protein‐coupled receptor X2 high expression cell membrane chromatography was coupled online with liquid chromatography and mass spectrometry and successfully used to screen anti‐anaphylactoid components from Magnolia biondii Pamp. Fargesin and pinoresinol dimethyl ether were identified as potential anti‐anaphylactoid components. Bioactivity of these two components were investigated by β hexosaminidase and histamine release assays on mast cells, and it was found that these two components could inhibit β hexosaminidase and histamine release in a concentration‐dependent manner. This Mas‐related G protein‐coupled receptor X2 high expression cell membrane chromatography coupled online with liquid chromatography and mass spectrometry system could be applied for screening potential anti‐anaphylactoid components from natural medicinal herbs. This study also provided a powerful system for drug discovery in natural medicinal herbs. 相似文献
To enhance the extraction performance, a mesoporous silica was modified with ordered mesoporous carbon for solid‐phase microextraction. Three stainless‐steel wires coated with the mesoporous material were placed in a polyetheretherketone tube for getting an extraction tube. The tube was coupled to high‐performance liquid chromatography with diode array detector, and the online analysis system was constructed. Then its extraction performance was evaluated using hydrophobic polycyclic aromatic hydrocarbons, phthalates, and hydrophilic neonicotinoids. The best selectivity was presented for polycyclic aromatic hydrocarbons. Several main conditions were optimized such as sampling volume, sampling rate, methanol concentration in the sample, and desorption time, a rapid and sensitive analytical method was established toward polycyclic aromatic hydrocarbons. The analytical method exhibited wide linear range from 0.017 to 15 µg/L with acceptable correlation coefficients more than 0.9990, limits of detection in 0.005‐0.020 µg/L, limits of quantification ranging from 0.017 to 0.066 µg/L as well as large enrichment factors of 377‐2314. It was successfully applied to detect trace polycyclic aromatic hydrocarbons in some real water samples including tap water, snow water, and domestic sewage. 相似文献
With the environmental pollution and non‐renewable fossil fuels, it is imperative to develop eco‐friendly, renewable, and highly efficient electrocatalysts for sustainable energy. Herein, a simple electrospinning process used to synthesis Mo2C‐embedded multichannel hollow carbon nanofibers (Mo2C‐MCNFs) and followed by the pyrolysis process. As prepared lotus root‐like nanoarchitecture could offer rich porosity and facilitate the electrolyte infiltration, the Mo2C‐MCNFs delivered favourable catalytic activity for HER and OER. The resultant catalysts exhibit low overpotentials of 114 mV and 320 mV at a current density of 10 mA cm?2 for HER and OER, respectively. Furthermore, using the Mo2C‐MCNFs catalysts as a bifunctional electrode toward overall water splitting, which only needs a small cell voltage of 1.68 V to afford a current density of 10 mA cm?2 in the home‐made alkaline electrolyzer. This interesting work presents a simple and effective strategy to further fabricating tunable nanostructures for energy‐related applications. 相似文献
In this paper, we propose a coupled awareness—epidemic spreading model considering the heterogeneity of individual influences, which aims to explore the interaction between awareness diffusion and epidemic transmission. The considered heterogeneities of individual influences are threefold: the heterogeneity of individual influences in the information layer, the heterogeneity of individual influences in the epidemic layer and the heterogeneity of individual behavioral responses to epidemics. In addition, the individuals’ receptive preference for information and the impacts of individuals’ perceived local awareness ratio and individuals’ perceived epidemic severity on self-protective behavior are included. The epidemic threshold is theoretically established by the microscopic Markov chain approach and the mean-field approach. Results indicate that the critical local and global awareness ratios have two-stage effects on the epidemic threshold. Besides, either the heterogeneity of individual influences in the information layer or the strength of individuals’ responses to epidemics can influence the epidemic threshold with a nonlinear way. However, the heterogeneity of individual influences in the epidemic layer has few effect on the epidemic threshold, but can affects the magnitude of the final infected density.
34,354,966 active cases and 460,787 deaths because of COVID-19 pandemic were recorded on November 06, 2021, in India. To end this ongoing global COVID-19 pandemic, there is an urgent need to implement multiple population-wide policies like social distancing, testing more people and contact tracing. To predict the course of the pandemic and come up with a strategy to control it effectively, a compartmental model has been established. The following six stages of infection are taken into consideration: susceptible (S), asymptomatic infected (A), clinically ill or symptomatic infected (I), quarantine (Q), isolation (J) and recovered (R), collectively termed as SAIQJR. The qualitative behavior of the model and the stability of biologically realistic equilibrium points are investigated in terms of the basic reproduction number. We performed sensitivity analysis with respect to the basic reproduction number and obtained that the disease transmission rate has an impact in mitigating the spread of diseases. Moreover, considering the non-pharmaceutical and pharmaceutical intervention strategies as control functions, an optimal control problem is implemented to mitigate the disease fatality. To reduce the infected individuals and to minimize the cost of the controls, an objective functional has been constructed and solved with the aid of Pontryagin’s maximum principle. The implementation of optimal control strategy at the start of a pandemic tends to decrease the intensity of epidemic peaks, spreading the maximal impact of an epidemic over an extended time period. Extensive numerical simulations show that the implementation of intervention strategy has an impact in controlling the transmission dynamics of COVID-19 epidemic. Further, our numerical solutions exhibit that the combination of three controls are more influential when compared with the combination of two controls as well as single control. Therefore, the implementation of all the three control strategies may help to mitigate novel coronavirus disease transmission at this present epidemic scenario.
The molecular orientation of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) multilayers adsorbed on Au (111) surface has been investigated using angular dependent O K-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The significant angular dependence of important resonant structures (π* and σ*) reveals that PTCDA molecules adopt an ordered geometry on the substrate surface. The average tilt angle of the PTCDA molecular planes is 27°±10° from the Au (111) surface. 相似文献