Structural and textural features of TiO<Subscript>2</Subscript>/SAPO-34 nanocomposite prepared by the sol–gel method

This paper focuses on the synthesis of nanocomposite materials, TiO₂/SAPO-34, using the sol–gel method, which involves preparing a mixture between as-synthesized or calcined SAPO-34 zeolite and TiO₂ gel under hydrothermal crystallization and then calcining it at 400 °C for the formation of the TiO₂ anatase phase. The structural and textural features of the obtained materials were determined by various physico-chemical techniques such as thermogravimetric analysis, X-ray diffraction, scanning electronic microscopy, nitrogen sorption at 77 K, energy dispersive X-ray analysis and ultraviolet–visible spectrometry. The DRX results showed that calcination at 400 °C of the mixture between the calcined SAPO-34 and TiO₂ gel led to the collapse of the original framework of zeolite, but formed the anatase TiO₂ in a nano-spherical morphology; however, the use of as-synthesized SAPO-34 supports provides a mixture phase between SAPO-34 and TiO₂ anatase after calcination. The photocatalytic properties of the SAPO-34/TiO₂ and TiO₂-type materials were tested for the removal of methylene blue (MB) dye. The MB degradation proved to increase as a function of contact time, catalyst mass and the initial concentration of MB.     

Impact dynamics of surfactant laden drops: dynamic surface tension effects

We study the impact and subsequent retraction of aqueous surfactant-laden drops upon high-speed impact on hydrophobic surfaces. Without surfactants, a rapid expansion of the drop due to the fluid inertia is followed by a rapid retraction, due to the wetting incompatibility. With surfactants, the retraction can be partly or completely inhibited. We provide quantitative measurements showing that both the expansion and the retraction dynamics depend not only on the equilibrium surface tension (ST) but also on the dynamic tension of the surfactant solutions; the latter varies significantly between different surfactants.     

Molecular Docking of SP40 Peptide towards Cellular Receptors for Enterovirus 71 (EV-A71)

Enterovirus 71 (EV-A71) is one of the predominant etiological agents of hand, foot and mouth disease (HMFD), which can cause severe central nervous system infections in young children. There is no clinically approved vaccine or antiviral agent against HFMD. The SP40 peptide, derived from the VP1 capsid of EV-A71, was reported to be a promising antiviral peptide that targeted the host receptor(s) involved in viral attachment or entry. So far, the mechanism of action of SP40 peptide is unknown. In this study, interactions between ten reported cell receptors of EV-A71 and the antiviral SP40 peptide were evaluated through molecular docking simulations, followed by in vitro receptor blocking with specific antibodies. The preferable binding region of each receptor to SP40 was predicted by global docking using HPEPDOCK and the cell receptor-SP40 peptide complexes were refined using FlexPepDock. Local molecular docking using GOLD (Genetic Optimization for Ligand Docking) showed that the SP40 peptide had the highest binding score to nucleolin followed by annexin A2, SCARB2 and human tryptophanyl-tRNA synthetase. The average GoldScore for 5 top-scoring models of human cyclophilin, fibronectin, human galectin, DC-SIGN and vimentin were almost similar. Analysis of the nucleolin-SP40 peptide complex showed that SP40 peptide binds to the RNA binding domains (RBDs) of nucleolin. Furthermore, receptor blocking by specific monoclonal antibody was performed for seven cell receptors of EV-A71 and the results showed that the blocking of nucleolin by anti-nucleolin alone conferred a 93% reduction in viral infectivity. Maximum viral inhibition (99.5%) occurred when SCARB2 was concurrently blocked with anti-SCARB2 and the SP40 peptide. This is the first report to reveal the mechanism of action of SP40 peptide in silico through molecular docking analysis. This study provides information on the possible binding site of SP40 peptide to EV-A71 cellular receptors. Such information could be useful to further validate the interaction of the SP40 peptide with nucleolin by site-directed mutagenesis of the nucleolin binding site.     

新型联苯胺基窄带隙共轭聚合物的光学及电化学性能研究

随着化石燃料的日益枯竭,人类社会对能源的需求在不断增长。为了平衡能量应用需求并提升能量使用效率,开发高效能量转换材料与电化学储能材料成为当前研究的重要课题。导电聚合物基电极材料面临着相应储能器件能量密度、功率密度、循环性能不高的挑战,需进行结构改性提高电导率、改善界面性质。鉴于共轭高分子的电子结构、光学及电化学性质由共轭链骨架结构决定,对导电共轭聚合物进行结构修饰以提升其电荷传输性能和载流子迁移率,进而设计合成新型高迁移率导电聚合物基共轭聚合物是提高相应器件特性的关键所在。已有研究大多借助复杂的结构设计来实现提升迁移率,设计合成了结构简单,有助提升电荷迁移的新型窄带隙聚联苯胺基共轭聚合物聚物。通过光谱学及电化学方法对材料结构与性能进行了表征分析。采用核磁共振氢谱、红外光谱,X射线粉末衍射对单体及聚合物进行了结构表征,通过紫外光谱、紫外可见漫反射、循环伏安、计时电位、交流阻抗对其进行了光学及电化学性能测试。结果表明,成功制得具有预期结构的共轭聚合物,所得聚合物结晶性较佳,光学带隙E_g^opt为1.85eV,HOMO及LUMO能级分别为-5.44和...     

An alkylzinc bromide and a lithium alkyldibromozincate containing tris(organosilyl)methyl groups

The lithium reagent (3) reacts with a molar equivalent of anhydrous zinc bromide to give the dimeric compound (2a), in which zinc is four-coordinate. The product from a similar reaction with Li{C(SiMe₃)₂(SiMe₂NPhMe)} is the lithium zincate [Li(THF)₂(μ-Br)₂Zn{C(SiMe₃)₂(SiMe₂NPhMe)}] (4), in which the zinc is only three-coordinate. The crystal structures of 2a and 4 have been determined.     

Silica/Polyamide Nanocomposite Synthesis via an Original Double Emulsification Process in Miniemulsion

Summary: A new method for the encapsulation of inorganic charges by an organic polymer by a reactive double emulsification process is proposed. This work is especially novel since it is highly unusual to encounter polymerization reactions in such a double emulsification process. Silica was first synthesized in cyclohexane using a sol–gel process in an inverse microemulsion in the presence of a non‐ionic surfactant (nonylphenyl ether polyoxyethylene), tetraethoxysilane, and concentrated ammonia. The coupling agent, 3‐aminopropyl triethoxysilane, was then grafted onto the surface of the silica nanoparticles. In a third step, direct miniemulsions were prepared from the microemulsion containing the functionalized silica nanoparticles. The miniemulsions were prepared using sodium dodecylsulfate as the surfactant and cetyl alcohol as the costabilizer. Finally, an interfacial polycondensation occurred between a diamine added to the external phase and sebacoyl chloride in solution in the dispersed phase. The formation of polyamide latexes was proven using infrared spectroscopy, and observation of the nanocomposites by transmission electron microscopy showed mean diameters of 100 nm.

TEM micrograph of silica/polyamide nanocomposite particles     

Quantitative on-line preconcentration-liquid chromatography coupled with tandem mass spectrometry method for the determination of pharmaceutical compounds in water

One of the current environmental issues concerns the presence and fate of pharmaceuticals in water bodies as these compounds may represent a potential environmental problem. The characterization of pharmaceutical contamination requires powerful analytical method able to quantify these pollutants at very low concentration (few ng L⁻¹).