An investigation for structure transformation in electric pulse modified liquid aluminum

The electric pulse (EP) modification of liquid metal is a novel method for grain refinement. In this work, the structure tests of EP-modified liquid aluminum were conducted and investigated using high-temperature X-ray diffractometer by virtue of the outstanding structural heredity of EP-modified liquid aluminum. The results show that the EP-modified liquid structure tends to be slack and unordered with increasing temperature similar to that of the unmodified. Nevertheless, the quantitative characterization denoted by the liquid structural parameters exhibits its discrepancy. At the modifying temperature of 750 °C, the order of degree of EP-modified liquid aluminum is remarkably strengthened and the value of average atomic number per cluster changes from 119 (no EP) up to 174 (EP) by an increase of 46%. These tests experimentally testified Wang's electric pulse modification (EPM) model that was built only by phenomenology, and hereby the mechanism of grain refinement resulting from EPM is further elucidated.     

Energy transfer between Eu3+ ions in a lattice with two different crystallographic sites: Y2O3:Eu3+, Gd2O3:Eu3+ and Eu2O3

The Eu³⁺ ion occupies two different crystallographic sites in (Y_1−xEu_x)₂O₃ and (Gd_1−xEu_x)₂O₃, with site symmetry S₆ and C₂. Energy transfer over more than 7 Å occurs from Eu³⁺ (S₆) ions to Eu³⁺ (C₂) ions. This is shown to be a direct one-phonon assisted process, in combination with a one-site resonant two-phonon assisted process at higher temperatures. For x = 1 there is energy migration over the Eu³⁺ (C₂) sublattice to quenching impurities. The presence of cooperative absorption points to superexchange interaction between the Eu³⁺ ions.     

Hepatitis C Virus NS3/4A Inhibition and Host Immunomodulation by Tannins from Terminalia chebula: A Structural Perspective

Terminalia chebula Retz. forms a key component of traditional folk medicine and is also reported to possess antihepatitis C virus (HCV) and immunomodulatory activities. However, information on the intermolecular interactions of phytochemicals from this plant with HCV and human proteins are yet to be established. Thus, by this current study, we investigated the HCV NS3/4A inhibitory and host immune-modulatory activity of phytocompounds from T. chebula through in silico strategies involving network pharmacology and structural bioinformatics techniques. To start with, the phytochemical dataset of T. chebula was curated from biological databases and the published literature. Further, the target ability of the phytocompounds was predicted using BindingDB for both HCV NS3/4A and other probable host targets involved in the immune system. Further, the identified targets were docked to the phytochemical dataset using AutoDock Vina executed through the POAP pipeline. The resultant docked complexes with significant binding energy were subjected to 50 ns molecular dynamics (MD) simulation in order to infer the stability of complex formation. During network pharmacology analysis, the gene set pathway enrichment of host targets was performed using the STRING and Reactome pathway databases. Further, the biological network among compounds, proteins, and pathways was constructed using Cytoscape 3.6.1. Furthermore, the druglikeness, side effects, and toxicity of the phytocompounds were also predicted using the MolSoft, ADVERpred, and PreADMET methods, respectively. Out of 41 selected compounds, 10 were predicted to target HCV NS3/4A and also to possess druglike and nontoxic properties. Among these 10 molecules, Chebulagic acid and 1,2,3,4,6-Pentagalloyl glucose exhibited potent HCV NS3/4A inhibitory activity, as these scored a lowest binding energy (BE) of −8.6 kcal/mol and −7.7 kcal/mol with 11 and 20 intermolecular interactions with active site residues, respectively. These findings are highly comparable with Asunaprevir (known inhibitor of HCV NS3/4A), which scored a BE of −7.4 kcal/mol with 20 key intermolecular interactions. MD studies also strongly suggest that chebulagic acid and 1,2,3,4,6-Pentagalloyl glucose as promising leads, as these molecules showed stable binding during 50 ns of production run. Further, the gene set enrichment and network analysis of 18 protein targets prioritized 10 compounds and were predicted to potentially modulate the host immune system, hemostasis, cytokine levels, interleukins signaling pathways, and platelet aggregation. On overall analysis, this present study predicts that tannins from T. chebula have a potential HCV NS3/4A inhibitory and host immune-modulatory activity. However, further experimental studies are required to confirm the efficacies.     

有效应力升降过程中不同饱和度水合物沉积物渗透率实验研究

为了研究天然气水合物开采过程中水合物饱和度和有效应力变化对含水合物沉积层渗透率变化规律的影响,利用自主研制的水合物沉积物合成与三轴渗流实验一体化装置,进行了有效应力升降过程中不同饱和度水合物沉积物渗透性实验。结果表明:有效应力升降过程中,不同饱和度水合物沉积物的渗透率与有效应力均呈负指数规律变化,并表现出在低有效应力阶段渗透率变化的幅度大于高有效应力阶段;有效应力升降过程中,试样产生的不可恢复变形使渗透率不能完全恢复,造成渗透率永久损失;有效应力不变时,水合物沉积物的渗透率与水合物饱和度呈负指数规律变化,且曲线的斜率随饱和度增加由大变小;水合物的饱和度越大,最大渗透率损害率越大,渗透率恢复的程度越差。     

Conformational analysis of some 11, 12-dihydrodibenz[B,F][1, 5]oxazocin-6-one derivatives by NMR spectroscopy

A variable temperature 200 MHz ¹H NMR investigation of some N-acylsubstituted 11, 12-dihydrodibenz[b, f][1, 5]oxazocin-6-ones showed the presence at room temperature of at least two conformationally restricted diastereomers (and their enantiomers) which molecular mechanics calculations strongly suggested to be a boat-like structure (major conformer) and a pseudo-chair and/or twistboat-like structure (minor conformer). The diastereomersinterconvert through a bond rotation mechanism just above room temperature (51-54°C, depending upon the nature of the N-acyl substituent), and the boat enantiomers interconvert at higher temperatures (75-95°C, depending upon the nature of the N-acyl substituent and the substitution pattern of the aromatic rings) via a ring inversion process. The N-acyl groups exocyclic to the eight-membered ring are shown to wholly exist - probably as a result of severe dipole: dipole interactions - in the sterically disfavoured conformation where the alkyl substituent bonded to the exocyclic carbonyl carbon atom is trans to the benzylic methylene group. Corresponding N-unsubstituted derivatives exhibit rapid ring inversion on the NMR time scale at room temperature.     

The nuclear pore complex: biochemical machine or Maxwell demon?

The nuclear pore complex sits as the gateway between the genomic, nuclear environment and the primarily enzymatic realm of the cytoplasm. Large channels traversing the two membranes of the nuclear envelope, the nuclear pores govern the passage of specific molecules between these two major compartments of the cell. Its ability to limit passage to specific molecules, and furthermore to pump them against a gradient in concentration, raises intriguing physical questions. This article reviews basic aspects of the structure and operation of this biochemical pump, whose thermodynamic cycle differs from that of conventional machines.     

A convenient one-pot synthesis of 4-amino-3-arylpyrazoles from α-phthaloylaminoacetophenones

Condensation of α-phthaloylaminoacetophenones 1a-c with N,N-dimethylformamide dimethyl acetal afforded the novel enamines 3a-c. Cyclization of 3 with hydrazine, alkylhydrazine or phenylhydrazine salts (4a-d) gave 4-phthaloylamino-3-arylpyrazoles 7–9 in high yields. Deprotection of 7–9 was accomplished with hydrazine to provide 4-amino-3-arylpyrazoles 5 in good yields.     

高效液相色谱法测定环境水中痕量4,4′-二氨基联苯、4-硝基酚和苯酚

采用ＰｈｅｎｏｍｅｎｅｘＳｐｈｅｒｅｘＣ１８色谱柱,以含５０ｍｍｏｌ／Ｌ乙酸－乙酸钠缓冲溶液（ｐＨ６．０）的Ｖ（乙腈）∶Ｖ（乙醚）∶Ｖ（水）＝１２∶１０∶７８混合溶液为流动相,用分光光度法检测,检测波长为２７５ｎｍ,在１６ｍｉｎ内实现了４,４′－二氨基联苯、４－硝基酚和苯酚的同时分离测定。检测限分别为０．１４,０．１９和０．０８ｎｇ。标准回收率分别为９８．８５％,９８．１５％和９８．１０％。方法灵敏度高,用于环境水样分析时结果令人满意。     

高效液相色谱法测定全血中骨碱性磷酸酶的活力

 建立了测定全血中骨碱性磷酸酶(BALP)的高效液相色谱法(HPLC)。色谱柱为SpectraPhysicsODS反相柱,以V(0.01mol/L乙酸,pH4.8)∶V(甲醇)=70∶30的溶液为流动相,流速为0.8mL/min,检测波长为275nm。当BALP的质量浓度为8～200mg/L时,其活性对峰面积呈良好的线性关系(r=0.996),检测限为3ng。该方法简便、快速、可靠,可用于临床测定全血中的BALP。     

Preparation and Application of All Solid State Tramadol Selective Electrode

Hydrochloric Tramadol is a safe effective and not addictive emollient, the methods to gauge the quantity of it are Ultraviolet Spectrophotometry,HPLC, Gas Chromatography-Mass Spectrometry and so on.