超低甲醛硬挺剂WD-2的合成

三聚氰胺和甲醛经羟甲基化、醚化反应,生成甲醚化六羟甲基三聚氰胺树脂.探讨了该硬挺剂的制备工艺和条件,通过浓缩脱醛、添加捕醛剂DF-460,获得了性能稳定的超低醛硬挺剂WD-2.经实验室合成与大釜车间生产,获得了一种新型的硬挺整理剂.     

Mass spectrometry combined with oxidative labeling for exploring protein structure and folding

This review discusses various mass spectrometry (MS)‐based approaches for exploring structural aspects of proteins in solution. Electrospray ionization (ESI)–MS, in particular, has found fascinating applications in this area. For example, when used in conjunction with solution‐phase hydrogen/deuterium exchange (HDX), ESI–MS is a highly sensitive tool for probing conformational dynamics. The main focus of this article is a technique that is complementary to HDX, that is, the covalent labeling of proteins by hydroxyl radicals. The reactivity of individual amino acid side chains with ^. OH is strongly affected by their degree of solvent exposure. Thus, analysis of the oxidative labeling pattern by peptide mapping and tandem mass spectrometry provides detailed structural information. A convenient method for ^. OH production is the photolysis of H₂O₂ by a pulsed UV laser, resulting in oxidative labeling on the microsecond time scale. Selected examples demonstrate the use of this technique for structural studies on membrane proteins, and the combination with rapid mixing devices for characterizing the properties of short‐lived protein (un)folding intermediates. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:651–667, 2010     

黄花菜中黄酮的提取及其对羟自由基的作用

本文以黄花菜为原料,对提取黄酮类化合物的最佳工艺条件进行了研究。结果表明:最佳条件为:水浴温度为75℃,提取时间为2h,乙醇浓度为95%,料液比1:20。此条件下测的其总黄酮含量为6.98%。且该提取物对羟自由基有良好的清除效果。     

Active warm-water fish gelatin film containing oxygen scavenging system

An oxygen scavenging system (OSS), composed of oxygen scavenging nanoparticles and iron chloride (II), was incorporated into warm-water fish gelatin film. Surface morphology, cross sectional images, and mechanical, barrier, and optical properties of the oxygen scavenging fish gelatin (OSFG) film were compared to those of the unmodified fish gelatin (UMFG) film. Results indicated that the OSS was well incorporated into the OSFG film structure. The OSFG film had rough film surface, increased water vapor and oxygen permeability, and decreased tensile strength due to the incorporation and agglomerations of the OSS. The incorporation of the OSS also caused color and haze alterations to the OSFG film. In addition, the oxygen scavenging capability of the OSFG film was investigated. The initial oxygen content (%) in the cup headspace, 20.90%, was decreased to 4.56% after 50 days of storage. The OSFG film had good oxygen scavenging capacity, 1969.08 cc O₂/m²/mil, and moisture was used as the activator to trigger the oxygen scavenging reaction.     

Visible light response photocatalytic water splitting over CdS-pillared zirconium–titanium phosphate (ZTP)

With an attempt to extend the light absorption towards the visible range and inhibit the rapid recombination of excited electrons/holes, a new type photocatalysts, cadmium sulfide intercalated zirconium–titanium phosphate (CdS–ZTP) was synthesized. The photocatalysts were characterized by small angle X-ray diffraction studies (SAXS), N₂ adsorption–desorption studies, diffused reflectance UV–vis (DRUV–vis) spectroscopic analysis, photoluminescence studies (PL), scanning electron microscopic/energy dispersive spectroscopic (SEM/EDS), X-ray photoelectron spectroscopic (XPS) studies etc. The samples exhibit a unique property of optical absorption in UV and visible regions with a wavelength, λ ≤ 450 nm followed by a clear long tail up to 700 nm. The pillared materials showed excellent activity for UV–visible light driven hydrogen production from photocatalytic splitting of water without using any co-catalyst. The photocatalytic activity of this cadmium sulfide pillared catalyst, as well as that of neat cadmium sulfide powder, was monitored for the visible light-induced evolution of hydrogen from water in the presence of hole scavenger, sulfide (S²⁻).     

Radical Reaction Mechanisms in Infrared Multiphoton Dissociation of UF6 with Scavenger Gases

Abstract

The radical reaction mechanisms in the presence of F-atom scavenger gases were investigated in the p-H₂ Raman laser-induced infrared multiphoton dissociation (IRMPD) of gaseous ²³⁶UF₆/²³⁸UF₆ cooled to —35°C in a static gas cell. When CH₄ was added as a scavenger of F-atoms produced via IRMPD of UFC, the dissociation rate of UF6 became several tens of times larger than when no scavenger gas was added. Gas-chromatographic analysis revealed that as low as 7% of the nascent CH₃ radicals were involved in the radical reaction with UF₆. On the other hand, H₂ and C₂H₆ were found to increase both the dissociation rate of UF₆ and the contribution of this non-selective reaction. These results agreed with those obtained in the UV photolysis of UF₆ with scavengers.     

Reactivation of human acetylcholinesterase and butyrylcholinesterase inhibited by leptophos-oxon with different oxime reactivators in vitro

We have evaluated in vitro the potency of 23 oximes to reactivate human erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE) inhibited by racemic leptophos-oxon (O-[4-bromo-2,5-dichlorophenyl]-O-methyl phenyl-phosphonate), a toxic metabolite of the pesticide leptophos. Compounds were assayed in concentrations of 10 and 100 μM. In case of leptophos-oxon inhibited AChE, the best reactivation potency was achieved with methoxime, trimedoxime, obidoxime and oxime K027. The most potent reactivators of inhibited BChE were K033, obidoxime, K117, bis-3-PA, K075, K074 and K127. The reactivation efficacy of tested oximes was lower in case of leptophos-oxon inhibited BChE.     

Modified Porous Clay Heterostructures by Organic–Inorganic Hybrids for Nanocomposite Ethylene Scavenging/Sensor Packaging Film

Porous clay heterostructures (PCHs) were prepared by the surfactant‐directed assembly of mesostructured silica within the two‐dimensional galleries of clays. PCH is an interesting material for use as an entrapping system (for example, as an ethylene scavenger) because of its high surface area with uniform and specific pore sizes. In the present work, the PCH was synthesized within the galleries of bentonite by the polymerization of tetraethoxysilane (TEOS) in the presence of surfactant micelles. In addition, mesoporous clay was modified by an organic–inorganic hybrid material through the co‐condensation reaction of TEOS with the functional groups (methyl and thiol) designated as hybrid organic–inorganic PCH (HPCH) and mercaptopropyl functionalized PCH (MPPCH), respectively. The synthesized PCH, HPCH and MPPCH were blended with polypropylene (PP) to produce PCH/PP, HPCH/PP and MPPCH/PP for ethylene scavenging blown films. All nanocomposite films were evaluated as ethylene sensors by measuring the conductivity changes by the attachment time with the ethylene gas. According to the surface characterization, the specific surface areas of modified PCHs increased from 31 to about 500 m²/g. From the ethylene adsorption results, the PCH, HPCH and MPPCH show higher efficiency in adsorbing ethylene gas than those of bentonite because of the non‐polar property of the modified functional groups. Subsequently, the electrical conductivity of the nanocomposite films decreased when they react with the longer attachment time to the ethylene gas, and the largest conductivity drop resulted from the MPPCH/PP nanocomposite films. Copyright © 2011 John Wiley & Sons, Ltd.