New synthetic corticosteroids inhibit Epstein–Barr virus release

Novel spiroandrostene-17,6'-[1,3,4]thiadiazines obtained by synthesis from 16β,17β-epoxy-17-isopregn-5-en-3β-ol-20-one and N-aryl-2-hydrazino-2-thioxoacetamide efficiently inhibited the release of Epstein–Barr virus from cells carrying the virus in culture. Other studied steroids, such as Spirolactone, Digitonin, Diosgenin, and Hecogenin were inactive. DMSO alone was found to inhibit the virus release, as well, likely, because of changing properties of the cell membranes. The novel steroids, Spironolactone and most analogues display no or low cell toxicity while Digitonin produced a significant toxic effect.     

Bond orders and electron delocalization indices for S–N,S–C and S–S bonds in 1,2,3-dithiazole systems

A parametric QTAIM-based (topological) model of bond orders and a modification of the Pauling bond order model are proposed for N,S-containing heterocycles, in particular, for 1,2,3-dithiazoles and 1,2,3-dithiazolium systems, which are prone to the formation of stable radicals and therefore are promising compounds in photovoltaics. These models have been parameterized for covalent S–N, S–C and S–S bonds using the electron delocalization indices. A modified Pauling’s bond order model uses turning radii, that is, the distances within which the potential acting on an electron in a system still tends to return that electron to the atomic basin, and avoids the need to choose the hybridization state of bound atoms arbitrarily.     

Efficient production of nanoporous silicon carbide from rice husk at relatively low temperature

Nanoporous silicon carbide with a specific surface area of up to 186.45 m² g⁻¹ has been efficiently synthesized from waste rice husk using a magnesiothermic reduction at 950 °C as a key step. Throughout the entire process, the recovery rates of silicon, potassium and phosphorus from rice husk can reach 88.46, 91.5 and 65.5%, respectively. Turning rice husk waste into a real treasure, this promising method for producing porous SiC protects the environment and brings economic benefits.     

Easy size control of polymer nanoparticles obtained by emulsification–evaporation technique in a microfluidic reactor

The production of polymer nanoparticles with a narrow size distribution on standard T- and X-configuration microfluidic chips with a channel size of 100 μm has been achieved. Introducing ethanol into the aqueous phase in 1:9 ratio (v/v) allowed one to reduce the surface tension of the contacting phases and obtain nanoparticles in the range of 100–150 nm. This makes our approach promising for development of nanoscale drug delivery systems.     

Metabolomics techniques applied in the investigation of phenolic acids from the agro-industrial by-product of Carapa guianensis Aubl

Processing of Carapa guianensis seeds to obtain oil on an industrial scale generates a significant amount of by-product, approximately 66% w/w, which is called cake and is a potential source of biomolecules, including simple phenolic structures. For this reason, studies were carried out on the chemical profiles of hydrolyzed extract from this agro-industrial by-product through High Performance Thin-Layer Chromatography (HPTLC) and Gas Chromatography coupled to Mass Spectrometry (GC–MS). These techniques were used to detect metabolic classes and/or groups, and to identify, for the first time, thirteen simple phenolic acids in this by-product. The sample antioxidant capacity was determined by methods of 2,2-diphenyl-1-picrylhydrazyl (DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS⁺) radicals direct sequestration. The hydrolyzed fraction showed a total of 63.47% in the relative abundance of the total of compounds, standing out: p-hydroxybenzoic acid (39.19%) and protocatechuic acid (3,4-dihydroxybenzoic acid) (5.62%), both from hydroxybenzoic acids and 3-(3,4-dihydroxyphenyl)lactic acid, (7.76%) hydroxycinnamic acids derivatives. In these results, the fraction rich in simple phenolic acids was obtained, attributing the prominent behavior of this matrix antioxidant activity, expressed by (IC₅₀: of 16.42 µg/mL and 6.52 µg/mL for DPPH and ABTS⁺ radicals, respectively). The research demonstrated an alternative to applicability that involves sustainability from agro-industrial. These techniques were used to detect metabolic classes and/or groups, and to identify, for the first time, thirteen simple phenolic acids in this by-product, generating a process capable of converting biomass into a bioproduct, consisting of bioactive compounds, in addition to adding value to the industrial chain.     

过渡态理论在化学体系中的2个应用实例*

在大学本科一二年级的物理化学教学中,化学动力学章节的学习涉及到对不同时间尺度的认识。本文利用过渡态理论得到的速率常数表达公式,以乙烷分子碳/碳单键旋转和水分子氢键交换的动力学过程为例,对这2个应用实例的动力学过程所发生的时间尺度做出估算。这些时间尺度的估算对于学生理解不同动力学过程的物理图像至关重要,同时也有助于加强学生对重要公式的理解并能够将这些公式在化学体系中灵活运用。     

Biocatalytic process intensification via efficient biocatalyst immobilization,miniaturization, and process integration

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二羰基环戊二烯基（三环己基锡基）铁的晶体结构

关于（三烃基锡基）二数基环戊二烯基铁类配合物的合成反应已进行了许多研究D'，并发现某些这类配合物具有一定的催化聚合作用或抗肿瘤活性［'·'j．这类配合物中已见报道晶体结构的只有烃基为三苯基作配体时的配合物CP（CO）。FesnPh。D'，为了便于比较及研究结构和性能的关系，我们以三环已基为锡的配体，以与文献［'j中近似的方法合成了配合物CP（CO）。Fesfl（C6HI人，并进行了IR、NMR的测定．X光四圆衍射仪对所得单晶的结构测定结果表明，该配合物具有与CP（CO）。F。SnPh。相近的晶体结构．1标题配合物的制备与谱学表征1…     

Formation at low surfactant concentrations and characterization of mesoporous MCM-41

At low concentrations of cetyltrimethylammonium bromide,all silica-based mesoporous materials with hexagonal phase have been synthesized via interactions between self-assembled surfactant molecule aggregates and aniomc silicate polymers.The resulting materials are characterized by XRD,FT-IR,solid state 29Si MAS NMR,thermal analysis and N2 adsorption-desorption measurements.After soluble ions are removed,the interactors between surfactant micelles and silicate polymers are reorganized and then form mesostructures 1 he hexagonal framework is sonsistent with amorphous silica gel.The structures of materials depend on the synthesis conditions Hydrothermal process improves the interactions between molecules and increases the degree of framework silicon atom polymerization The.surface area and the mesopore volume of the material prepared at 100℃ increase by 87% and 71 %,respectively,compared with those obtained at room temperature.     

甲烷—空气燃烧中NOx生成的简化模型研究

用特征值－特征向量法对甲烷－空气燃烧时ＮＯＸ生成的化学反应机理进行了简化，得到了仅由１５个基元以应组成的简化反应模型。对比计算结果表明，该模型能在较宽燃空比内与全面模型很好吻合，因而可望用于燃烧过程数值模拟时对ＮＯＸ生成的预测