Palladium-Catalyzed Aminomethylation of Nitrodienes and Dienones via Double C-N Bond Activation

A new strategy for the generation of the active Pd-alkyl species from aminal via C-N bond activation has been established,in which the formation of zwitterionic...     

Hepatoprotective Effects of Ixeris chinensis on Nonalcoholic Fatty Liver Disease Induced by High-Fat Diet in Mice: An Integrated Gut Microbiota and Metabolomic Analysis

Ixeris chinensis (Thunb.) Nakai (IC) is a folk medicinal herb used in Mongolian medical clinics for the treatment of hepatitis and fatty liver diseases even though its pharmacological mechanism has not been well characterized. This study investigated the hepatoprotective mechanism of IC on mice with nonalcoholic fatty liver disease (NAFLD) by integrating gut microbiota and metabolomic analysis. A high-fat diet (HFD) was used to develop nonalcoholic fatty liver disease, after which the mice were treated with oral IC (0.5, 1.5 and 3.0 g/kg) for 10 weeks. HFD induced NAFLD and the therapeutic effects were characterized by pathological and histological evaluations, and the serum indicators were analyzed by ELISA. The gut microbial and metabolite profiles were studied by 16S rRNA sequencing and untargeted metabolomic analysis, respectively. The results showed that the administration of IC resulted in significant decreases in body weight; liver index; serum biomarkers such as ALT, TG, and LDL-C; and the liver inflammatory factors IL-1β, IL-6, and TNF-α. The 16S rRNA sequencing results showed that administration of IC extract altered both the composition and abundance of the gut microbiota. Untargeted metabolomic analysis of liver samples detected a total of 212 metabolites, of which 128 were differentially expressed between the HFD and IC group. IC was found to significantly alter the levels of metabolites such as L-glutamic acid, pyridoxal, ornithine, L-aspartic acid, D-proline, and N4-acetylaminobutanal, which are involved in the regulation of glutamine and glutamate, Vitamin B6 metabolism, and arginine and proline metabolic pathways. Correlation analysis indicated that the effects of the IC extract on metabolites were associated with alterations in the abundance of Akkermansiaceae, Lachnospiraceae, and Muribaculaceae. Our study revealed that IC has a potential hepatoprotective effect in NAFLD and that its function might be linked to improvements in the composition of gut microbiota and their metabolites.     

全自动固相萃取技术同时测定动物产品中9种磺胺药物残留

针对目前动物产品中兽药残留检测样品前处理繁琐的问题,应用全自动固相萃取技术对动物产品中9种磺胺类药物残留检测的样品前处理方法进行了系统的研究,对提取溶剂、固相萃取柱、淋洗液、洗脱溶剂及仪器分析条件进行了优化选择,建立了新型磺胺药物残留检测的全自动固相萃取净化方法.经不同检测单位验证,该方法的加标回收率为78.4%～107.8%,精密度为3.9%～11.0%检出限为0.010～0.020mg/kg,满足出口检测要求.     

Analysis of plasma migration components in Patrinia villosa (Thunb.) Juss. effective parts by UPLC–Q-TOF–MS

Patrinia villosa (Thunb.) Juss. (PVJ) is described as pungent, bitter and slightly cold in Chinese medicine, and is associated with the large intestine, stomach and liver meridians. The preliminary experiments of our research team proved that PVJ total flavonoids have excellent inhibitory effects on liver cancer cells. The present experiment uses the UPLC–Q-TOF–MS technology and serum pharmacochemistry methods to analyze the chemical components in vitro and in vivo of PVJ antiliver tumors. A total of 14 chemical components were identified in the total flavonoids extract of PVJ, and it is mainly composed of flavonoids, flavonones, flavonols and phenolic acids. At the same time, seven prototypical components and seven metabolic components were detected in the drug-containing plasma. Hydrocaffeate and scutellarein are the phase I metabolites of caffeic acid and scutellarin, respectively. Sulfated apigenin, sulfated luteolin, sulfated kaempferol and methylated kaempferol are the II phase metabolites of apigenin, luteolin, kaempferol, respectively. The experiment provides a reference for the research and development of antitumor drug candidates, and provides a basis for revealing the bioactive components of PVJ and the antitumor mechanism.     

High Catalytic Performance of Mesoporous Dual Brønsted Acidic Ternary Poly (Ionic Liquids) for Friedel‐Crafts Alkylation

A newfangled cross‐linked dual Brønsted acidic ternary mesoporous poly (ionic liquids)(MPILs) with mesoporous structure was successfully synthesized with divinylbenzene as cross linker, 1‐vinyl‐3‐butyl imidazole bromide and sodium p‐styrene sulfonate as functional group through an ordinary post‐modification method and anion exchange process. A sponge‐like mesoporous tunnel structure was observed and the obtained P (BVS‐SO₃H)‐SO₃CF₃ sample appeared a relatively high thermal stability, a large surface area (up to 286.8 m²/g) and great pore volume (0.73 cm³/g). The abundant dual acidic group of sulfonic acid and trifluoromethanesulfonic acid of the composite in the polymer framework impart Brønsted acidity. For the sake of demonstrating our claims, the sample has been used as a novel solid acid catalyst for the reaction of alkylation of o‐xylene with styrene to 1‐diphenylethane (PXE). Under optimal reaction conditions (reaction under 120 °C for 3 hr, catalyst amount was 0.5 wt% of the reaction system, and the mass ratio of o‐xylene/styrene was 7.5:1, a 100% conversion of styrene and 93.7% PXE yield was acquired. After four times recycle, the yield remains 53.3%. Comparing with the commercial liquid acid catalyst, it processing a higher catalytic property and recyclability. Moreover, this fresh dual acidic heterogeneous catalyst owning a promising future applied in other acidic catalytic reactions and provide a new method to modify catalyst.     

Neighbor Sum Distinguishing Index of Sparse Graphs

A proper k-edge coloring of a graph G is an assignment of one of k colors to each edge of G such that there are no two edges with the same color incident to a common vertex. Let f(v) denote the sum of colors of the edges incident to v. A k-neighbor sum distinguishing edge coloring of G is a proper k-edge coloring of G such that for each edge uv∈E(G), f(u)≠f(v). By χ'_∑(G), we denote the smallest value k in such a coloring of G. Let mad(G) denote the maximum average degree of a graph G. In this paper, we prove that every normal graph with mad(G) ■ and Δ(G) ≥ 8 admits a(Δ(G) + 2)-neighbor sum distinguishing edge coloring. Our approach is based on the Combinatorial Nullstellensatz and discharging method.     

Utilizing Vinylcyclopropane Reactivity: Palladium‐Catalyzed Asymmetric [5+2] Dipolar Cycloadditions

Vinylcyclopropanes (VCPs) are commonly used in transition‐metal‐catalyzed cycloadditions, and the utilization of their recently realized reactivities to construct new cyclic architectures is of great significance in modern synthetic chemistry. Herein, a palladium‐catalyzed, visible‐light‐driven, asymmetric [5+2] cycloaddition of VCPs with α‐diazoketones is accomplished by switching the reactivity of the Pd‐containing dipolar intermediate from an all‐carbon 1,3‐dipole to an oxo‐1,5‐dipole. Enantioenriched seven‐membered lactones were produced with good reaction efficiencies and selectivities (23 examples, 52–92 % yields with up to 99:1 er and 12.5:1 dr). In addition, computational investigations were performed to rationalize the observed high chemo‐ and periselectivities.     

Green synthesis and application of nanoscale zero-valent iron/rectorite composite material for P-chlorophenol degradation via heterogeneous Fenton reaction

A zero-valent iron/rectorite nanocomposite (NZVI/rectorite) was developed as a heterogeneous H₂O₂ catalyst for P-chlorophenol degradation. The physicochemical properties of NZVI/rectorite were characterized by various techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis. Results showed that NZVI sphere nanoparticles were successfully loaded on the rectorite surface with less aggregation and good dispersion. Moreover, compared with acid-leached rectorite (30.91 m²/g), the NZVI/rectorite appeared to have larger surface area (50.75 m²/g). In addition, the effects of pH, reaction time, initial P-chlorophenol concentration, catalyst amount, and H₂O₂ dosage on the P-chlorophenol degradation were systematically investigated. Results showed that NZVI/rectorite presents better properties for the degradation and mineralization of P-chlorophenol compared with pristine NZVI due to the large surface area, low aggregation, and good dispersion of the former. The degradation mechanisms of P-chlorophenol by NZVI/rectorite were adsorption and reduction coupled with a Fenton-like reaction. Four successive runs of the stability and regeneration study also showed that the NZVI/rectorite were unchanged even after 100% of P-chlorophenol degradation ratio. This study has extended the application of NZVI/rectorite as environment function material for the removal of P-chlorophenol from the environment.     

Atomic‐Scale Insight into Exsolution of CoFe Alloy Nanoparticles in La0.4Sr0.6Co0.2Fe0.7Mo0.1O3−δ with Efficient CO2 Electrolysis

In situ exsolution of metal nanoparticles in perovskite under reducing atmosphere is employed to generate a highly active metal–oxide interface for CO₂ electrolysis in a solid oxide electrolysis cell. Atomic‐scale insight is provided into the exsolution of CoFe alloy nanoparticles in La_0.4Sr_0.6Co_0.2Fe_0.7Mo_0.1O_3?δ (LSCFM) by in situ scanning transmission electron microscopy (STEM) with energy‐dispersive X‐ray spectroscopy and DFT calculations. The doped Mo atoms occupy B sites of LSCFM, which increases the segregation energy of Co and Fe ions at B sites and improves the structural stability of LSCFM under a reducing atmosphere. In situ STEM measurements visualized sequential exsolution of Co and Fe ions, formation of CoFe alloy nanoparticles, and reversible exsolution and dissolution of CoFe alloy nanoparticles in LSCFM. The metal–oxide interface improves CO₂ adsorption and activation, showing a higher CO₂ electrolysis performance than the LSCFM counterparts.     

OSCILLATION AND NON-OSCILLATION FOR SECOND-ORDER QUASI-LINEAR DIFFERENCE EQUATIONS

Some oscillation and non-oscillation criteria for second-order quasi-linear difference equations are given. The results in Zhang and Zhou [4] are improved.