Fabrication and invitro evaluation of electrospun gum ghatti-polyvinyl alcohol polymeric blend green nanofibre mat (GG-PVA NFM) as a novel material for polymeric scaffolds in wound healing

The present research is mainly based on the fabrication of biodegradable nanofiber mats (NFM) through the process of electrospinning using a novel combination of Gum Ghatti (GG) and Poly vinyl alcohol (PVA). The prepared NFM was crosslinked (CL-1) using Glutaraldeyde-HCl vapours and was characterized for its tensile strength along other analytical characterizations using FTIR, TGA, DSC and XRD. The mechanical strength of the NFM was found to be sufficiently high than in comparison to noncrosslinked sample and PVA NFM. The internal architecture of the CL-1 by use of atomic force microscopy (AFM) revealed that there was very well formed crosslinks suitable for drug loading as well as cell proliferation. The wound healing properties of the CL-1 in mice animal model indicated the healing within 5 days as compared to the control wound. Moreover, the sample was also analysed for its ability as polymeric scaffold and no toxicity was found onto the locally applied tissue on histological investigations.     

Temperature dependence of methanol and ethanol vapor sorption in polyhedral oligomeric silsesquioxane (POSS) containing methacrylate membranes

This study aimed to determine the solubility and temperature dependence of methanol and ethanol vapor caused by the difference in the substituents of polyhedral oligomeric silsesquioxane (POSS)-containing polymethacrylate membranes and the spacer length between the backbone and POSS backbone. Vapor sorption of methanol and ethanol was measured at 25°C, 35°C, and 45°C for three kinds of POSS-containing polymer membranes, namely, poly(methacryl isobutyl POSS), poly(methacrylate isobutyl POSS), and poly(methacryl phenyl POSS). The primary structures of the three POSS-containing polymer chains were columnar. The solubility of alcohol vapor on the POSS-containing polymer membranes followed the mechanism of solid adsorption and not the general dissolution diffusion. The sorption amount at all three temperatures was related to the surface area of the cylindrical primary structure and the solid adsorption property of the alcohol molecule of the POSS substituent. The sorption amount increased because of the large surface area and adsorption property of alcohol molecules. Although a typical glassy polymer shows exothermic mixing and a rubbery polymer displays endothermic mixing, the sample with the POSS substituent of isobutyl group exhibited an unusual behavior of endothermic mixing despite being a glassy polymer.     

Ag3PO4量子点/石墨相氮化碳纳米片复合光催化剂的制备及其对苯甲醇选择性氧化活性

以热氧化剥离法得到的超薄石墨相氮化碳(g-C₃N₄)纳米片为载体,首次在室温条件下,制备了系列Ag₃PO₄量子点/g-C₃N₄纳米片复合光催化剂;通过透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射光谱(UV-Vis DRS)、荧光光谱(PL),对复合光催化剂的形貌、结构和光学性质进行了表征,考察了系列光催化剂对苯甲醇的光催化选择性氧化性能。 结果表明,粒径为3~5 nm Ag₃PO₄颗粒均匀分散g-C₃N₄纳米片上,结晶度良好。 以乙腈为溶剂时,当m(Ag₃PO₄)/m(g-C₃N₄)=0.6时,苯甲醇具有32.1%的最大转化率,对产物苯甲醛具有90%的最高选择性;活性物种捕捉实验结果表明,该催化氧化反应的主要活性物是光生空穴的氧化作用,能带计算结果表明,该复合催化剂结构具有合适的苯甲醇的氧化电位而选择性生成苯甲醛。     

胶束电动毛细管色谱法分析玫瑰纯露中的苯乙醇

玫瑰纯露是玫瑰提取精油后的重要副产物,是玫瑰精油的饱和水溶液,不仅含有植物水溶活性成分,同时也保留了精油的芳香成分,含有矿物养分,具有抗衰老、清除自由基,抗过敏、抗菌、消炎、防紫外线损伤等功效,是继玫瑰精油之后护肤领域重要的优势产品之一,但目前尚无关于其质量控制的标准,市售产品质量参差不齐。为此,该研究发展了一种胶束电动毛细管色谱法用于快速检测玫瑰纯露中的指标成分苯乙醇。在实验过程中分析物的定性通过标准物质加标及紫外吸收可见光谱图比对确认。实验对缓冲溶液中硼砂浓度、十二烷基硫酸钠（SDS）浓度、分离电压、进样条件、检测条件等影响检测的关键因素进行了考察。在优化条件（分离缓冲溶液10 mmol/L Na₂ B₂ O₇ +15 mmol/L SDS,分离电压+20 kV,检测波长208 nm,进样5 kPa,5 s）下,玫瑰纯露样品在7 min内可以完成检测。本方法对苯乙醇检测的线性范围为0.50~1000 mg/L,线性相关系数（r ² ）为0.9990,检出限（LOD,S/N =3）为0.091 mg/L,定量限（LOQ,S/N =10）为0.35 mg/L,实际样品加标回收率为98.1%~102.7%（加标水平10、100、500 g/L）,相对标准偏差（RSD）≤2.8%。结果表明,该方法为玫瑰纯露及其制品的质量控制提供了一种简便、快速、灵敏、稳定的分析方法。     

Palladium complex in a room temperature ionic liquid: a convenient recyclable reagent for catalytic oxidation

Palladium (Pd)-catalyzed carbonylation of alcohols proceeds in ionic liquid (IL) media (1-ethyl-3-methylimidazolium hexafluorophosphate). Carbonylation of primary/secondary alcohols to aldehydes/ketones was greatly accelerated by the use of a Pd-based catalyst in the presence of NaOCl as an oxidant. The catalyst was more easier to recycle in the IL [Emim]PF₆ with an equal-proportioned CH₂Cl₂ than in the single CH₂Cl₂ or IL.     

聚乙烯醇/壳聚糖复合水凝胶的物理化学性质

测定了聚乙烯醇(PVA)和壳聚糖(CS)复合水凝胶的平衡含水量、熔融焓、等温溶胀动力学和非等温失水动力学等性质,讨论了水凝胶的组成和制备参数对这些性质的影响.结果显示:PVA/CS复合水凝胶具有适宜于软骨修复替代材料的网络结构和平衡含水量.CS与PVA复合减弱了凝胶的结晶度,但却增强了水与凝胶支架的相互作用.尽管水凝胶力学拉伸强度有所降低,但却优化了凝胶的生物相容性和降解能力.PVA/CS复合水凝胶是一种潜在的软骨修复材料,作为一种理论研究的模型体系,它将促进热力学在复杂医用材料方面的应用.     

Oxidation of aliphatic alcohols by triethylammonium chlorochromate in non-aqueous medium – A kinetic and mechanistic study

The oxidation of some aliphatic alcohols by triethylammonium chlorochromate (TriEACC) in dimethyl sulfoxide leads to the formation of the corresponding carbonyl compounds. The reaction is first order with respect to TriEACC. The reaction exhibited Michaelis–Menten type kinetics with respect to alcohol. The reaction is catalyzed by hydrogen ions. The hydrogen-ion dependence has the form: k_obs = a + b[H⁺]. The oxidation of [1,1-²H₂] ethanol (MeCD₂OH) exhibits a substantial primary kinetic isotope effect. Oxidation of aliphatic alcohol was studied in 19 different organic solvents. The solvent effect has been analysed using Kamlet’s and Swain’s multi-parametric equation. A suitable mechanism has been proposed.     

Highly Chemoselective Aerobic Oxidation of Amino Alcohols into Amino Carbonyl Compounds

The direct oxidation of unprotected amino alcohols to their corresponding amino carbonyl compounds has often posed serious challenges in organic synthesis and has constrained chemists to adopting an indirect route, such as a protection/deprotection strategy, to attain their goal. Described herein is a highly chemoselective aerobic oxidation of unprotected amino alcohols to their amino carbonyl compounds in which 2‐azaadamantane N‐oxyl (AZADO)/copper catalysis is used. The catalytic system developed leads to the alcohol‐selective oxidation of various unprotected amino alcohols, carrying a primary, secondary, or tertiary amino group, in good to high yield at ambient temperature with exposure to air, thus offering flexibility in the synthesis of nitrogen‐containing compounds.     

Following Solid‐Acid‐Catalyzed Reactions by MAS NMR Spectroscopy in Liquid Phase—Zeolite‐Catalyzed Conversion of Cyclohexanol in Water

A microautoclave magic angle spinning NMR rotor is developed enabling in situ monitoring of solid–liquid–gas reactions at high temperatures and pressures. It is used in a kinetic and mechanistic study of the reactions of cyclohexanol on zeolite HBEA in 130 °C water. The ¹³C spectra show that dehydration of 1‐¹³C‐cyclohexanol occurs with significant migration of the hydroxy group in cyclohexanol and the double bond in cyclohexene with respect to the ¹³C label. A simplified kinetic model shows the E1‐type elimination fully accounts for the initial rates of 1‐¹³C‐cyclohexanol disappearance and the appearance of the differently labeled products, thus suggesting that the cyclohexyl cation undergoes a 1,2‐hydride shift competitive with rehydration and deprotonation. Concurrent with the dehydration, trace amounts of dicyclohexyl ether are observed, and in approaching equilibrium, a secondary product, cyclohexyl‐1‐cyclohexene is formed. Compared to phosphoric acid, HBEA is shown to be a more active catalyst exhibiting a dehydration rate that is 100‐fold faster per proton.     

磷钼酸/聚苯乙烯/聚乙烯醇电纺纤维膜的制备及性能

采用静电纺丝法制备了磷钼酸/聚苯乙烯(PS)/聚乙烯醇(PVA)复合纤维,并将其模压成膜.利用红外光谱(IR)、扫描电子显微镜(SEM)及X射线能谱(EDX)等对复合纤维及其膜的结构与形貌进行表征,并对复合纤维膜的光催化性能、力学性能及在水中稳定性进行测试.结果表明,在复合纤维中磷钼酸的Keggin结构得到保持.PS与PVA质量比为1∶1时,复合纤维形貌最佳,表面光滑,直径较小且分布均匀,复合纤维的直径随着磷钼酸含量的增加而减小.将磷钼酸固载于复合纤维膜上比直接使用具有更高的光催化活性,光照25 min后接近98%的甲基橙降解;复合纤维膜易于回收再利用,5次重复使用后,复合纤维膜没有破损,磷钼酸损失较少,光催化性能无明显下降.复合纤维膜的强度随磷钼酸含量的增加先增大后减小,韧性随PVA含量的增加而增大,随磷钼酸含量的增加而减小.