Search

Herein, we report a regioselective cycloaddition strategy of N -aminopyridinium ylides with electron-deficient alkenes, in the presence of a hypervalent iodine reagent, PhI(OAc)2. A variety of multifunctionalized pyrazolo[1,5- a ]pyridine architectures were smoothly afforded by the reactions of pyridine-, quinoline-, and isoquinoline-based N -ylides with diverse alkenes with or without a halogen atom adjacent to the electron-withdrawing group (EWG) under facile conditions. [ABSTRACT FROM AUTHOR]

In this study, the wear characteristics of the die were tested and analyzed through compaction tests, and the distribution of wear depth along the direction toward the extrusion outlet was obtained. A discrete element method (DEM) model of the die's wear process was established. The results show that the severe wear area is located near the stop position of the compression rod, forming a plow-shaped wear area along the extrusion direction, accompanied by fatigue peeling. The wear depth gradually decreases towards the extrusion outlet. The DEM model partially reveals the occurrence of the wear phenomenon, but the particle motion speed deviates from the actual situation. The maximum compression force value range during the DEM compression stage is within the actual maximum compression force value range, and the relative error range of the average maximum compression force is less than 2%. By verifying the formula to calibrate the model, the calibrated model is compared with the actual mold wear, and the predicted value is close to the actual test result. The DEM can be used to explore the wear mechanism and predict the die's wear failure process, laying the foundation for optimizing die wear resistance design. [ABSTRACT FROM AUTHOR]

The crude protein (CP) content is an important determining factor for the quality of alfalfa, and its accurate and rapid evaluation is a challenge for the industry. A model was developed by combining Fourier transform infrared spectroscopy (FTIS) and chemometric analysis. Fourier spectra were collected in the range of 4000~400 cm−1. Adaptive iteratively reweighted penalized least squares (airPLS) and Savitzky–Golay (SG) were used for preprocessing the spectral data; competitive adaptive reweighted sampling (CARS) and the characteristic peaks of CP functional groups and moieties were used for feature selection; partial least squares regression (PLSR) and random forest regression (RFR) were used for quantitative prediction modelling. By comparing the combined prediction results of CP content, the predictive performance of airPLST-cars-PLSR-CV was the best, with an R P 2 of 0.99 and an RMSEP of 0.053, which is suitable for establishing a small-sample prediction model. The research results show that the combination of the PLSR model can achieve an accurate prediction of the crude protein content of alfalfa forage, which can provide a reliable and effective new detection method for the crude protein content of alfalfa forage. [ABSTRACT FROM AUTHOR]

This paper reviews the development and application of concentration gradient generators based on microfluidics. Generating solutions of varying concentrations is a frequent requirement in numerous experiments and applications. Traditional approaches involve the preparation of solutions with varying concentrations or the dilution of highly concentrated solutions. Nevertheless, these methods are intricate, time-consuming, and susceptible to errors. The advent of microfluidic concentration generators presents a novel concept for the realms of chemistry, biology, and medicine, allows biological or chemical experiments to be performed on a device with a measurement size of a few square centimeters or even smaller, thus greatly reducing the number of basic routine biological or chemical laboratory operations, such as sample preparation, reaction, separation, and analysis. In this review, we discuss the development and application of microfluidic concentration gradient generators through observation, introduce the development history of microfluidic concentration gradient generators and how they are used, summarize their wide range of applications in various fields, and discuss the possible future development direction of microfluidic concentration gradient generators. [ABSTRACT FROM AUTHOR]

Engineering efficient catalyst interfaces offers a constructive way to boost activity and stability in the field of water electrolysis. Here, unique core–shell FeCoS@CoMoP heterostructure nanoparticles are rationally fabricated on a porous Ni foam through hydrothermal and electrodeposition methods. The as-prepared electrocatalyst exhibits efficient pH-universal hydrogen evolution reaction (HER) activity along with a satisfactory alkaline oxygen evolution reaction (OER) performance, extremely small overpotentials, and Tafel values, achieving prominent durability and stability. A series of structural characterizations help identify the reactive centers during the catalytic procedure and the tight interfacial interaction between the shell and core materials. Density functional theory (DFT) calculations reveal that the surface electrodeposition of CoMoP not only tunes the d-band center but also obviously decreases the Gibbs free energies in the HER/OER processes. It can be expected that the three-dimensional self-supported catalytic system will hold strong promise for effective water splitting, energy storage, and energy transformation devices. [ABSTRACT FROM AUTHOR]

Viral myocarditis (VMC) is a common disease characterized by cardiac inflammation. AC-73, an inhibitor of CD147, disrupts the dimerization of CD147, which participates in the regulation of inflammation. To explore whether AC-73 could alleviate cardiac inflammation induced by CVB3, mice were injected intraperitoneally with AC-73 on the fourth day post-infection (dpi) and sacrificed on the seventh dpi. Pathological changes in the myocardium, T cell activation or differentiation, and expression of cytokines were analyzed using H&E staining, flow cytometry, fluorescence staining and multiplex immunoassay. The results showed that AC-73 alleviated cardiac pathological injury and downregulated the percentage of CD45+CD3+ T cells in the CVB3-infected mice. The administration of AC-73 reduced the percentage of activated CD4+ and CD8+ T cells (CD69+ and/or CD38+) in the spleen, while the percentage of CD4+ T cell subsets in the spleen was not changed in the CVB3-infected mice. In addition, the infiltration of activated T cells (CD69+) and macrophages (F4/80+) in the myocardium also decreased after the AC-73 treatment. The results also showed that AC-73 inhibited the release of many cytokines and chemokines in the plasma of the CVB3-infected mice. In conclusion, AC-73 mitigated CVB3-induced myocarditis by inhibiting the activation of T cells and the recruitment of immune cells to the heart. Thus, CD147 may be a therapeutic target for virus-induced cardiac inflammation. [ABSTRACT FROM AUTHOR]