Phenolic compounds from Anaphalis aureo-punctata

From the ethanolic extract of the whole plant of Anaphalis aureo-punctata, a new acylated flavonoid glycoside 3-O-kaempferol-3-O-acetyl-6-O-(p-coumaroyl)-β-D-glucopyranoside (1), and five known phenolic compounds 3-O-kaempferol-6- O- ( p-coumaroyl )-β-D-glucopyranoside ( 2 ), kaempferol-3- O-β-D-glucopyranoside 3,6-(4′-hydroxystyryl)-4-methoxy-2-pyrone (4), 2H-pyran-2-one, 6-[ 2-( 4-(β-D-glucopyranosyloxy ) phenyl ) ethenyl ]-4-methoxy-( E ) (5) and 4-hydroxy-3-methoxycinnamic hexacosyl ester (6) were isolated. Their structures were established by spectral methods (UV, IR, MS, 1D, 2D-NMR). The flavonoid glycosides, 1, 2 and 3 showed markedly inhibited oxidative DNA strand breaks induced by Fenton reaction and NADH/PMS in a concentration-dependent manner.     

新型稀土固体超强酸催化剂的制备及表征

采用分别沉淀-混合-浸渍法制备了稀土固体S2O82-/ZrO2-SiO2-Sm2O3催化剂.分别以乙酸丁酯和乳酸丁酯的合成为探针反应,考察了不同制备条件对催化剂活性的影响及催化剂的稳定性,并采用IR,XRD,DTA/TGA,TEM,BET和XPS等手段对催化剂进行了表征,结果表明本文制得的催化剂属无定型、桥式结构为主的固体超强酸,且其稳定性及活性均比SO42-/ZrO2-SiO2有较大的提高.     

在PVA存在下Os-SnCl_2-亮绿离子缔合体系的研究高纯镍中微量Os的测定

本文研究了Os-SnCl_2-PVA-亮绿离子缔合体系的显色反应,摩尔吸光系数ε_(434)为5.6×10~6L·mol~(-1)·cm~(-1),锇含量在0.1～0.7μg/25mL范围内遵守比耳定律,室温下显色后,吸光度在110min内稳定。研究了30种外来离子的影响,并进行了高纯镍中微量锇的测定。     

精神分裂症患者头发5种元素含量变化及临床意义

采用原子吸收光谱法测定了９６例精神分裂症患者和１０１名正常对照组的头发Ｚｎ、Ｃｕ、Ｆｅ、Ｃａ、Ｍｇ元素含量。结果发现，精神分裂症患者头发ｎ和Ｍｇ元素含量明显低于对照组，而Ｃｕ、Ｆｅ和Ｃａ元素含量明显高于对照组。提示精神分裂症的发病，可能与Ｚｎ和Ｍｇ元素含量降低，Ｃｕ、Ｆｅ和Ｃａ元素含量升高有关。     

In-channel indirect amperometric detection of nonelectroactive anions for electrophoresis on a poly(dimethylsiloxane) microchip

In the present paper, we describe a microfluidics-based sensing system for nonelectroactive anions under negative separation electric field by mounting a single carbon fiber disk working electrode (WE) in the end part of a poly(dimethylsiloxane) microchannel. In contrast to work in a positive separation electric field described in our previous paper (Anal. Chem. 2004, 76, 6902-6907), here the electrochemical reduction reaction at the WE is not coupled with the separation high-voltage (HV) system, whereas the electrochemical oxidation reaction at the WE is coupled with the separation HV system. The electroactive indicator is the carbon fiber WE itself but not dissolved oxygen. This provides a convenient and sensitive means for the determination of nonelectroactive anions by amperometry. The influences of separation voltage, detection potential, and the distance between the WE and the separation channel outlet on the response of the detector have been investigated. The present detection mode is successfully used to electrochemically detect F-, Cl-, SO4(2-), CH3COO-, H2PO4-. Based on the preliminary results, a detection limit of 2 microM and a dynamic range up to three orders of magnitude for Cl- could be achieved.     

Modeling the reaction mechanisms for redox regulation of protein tyrosine phosphatase 1B activity

Protein tyrosine phosphatase 1B (PTP1B) functions by removing the phosphoryl group from tyrosinephosphorylated proteins in insulin signaling and metabolism. The regeneration of the active site involves a sulphenylamide intermediate derived from the intrastrand cross-linking between the catalytic serine and the neighboring backbone nitrogen. Two mechanisms have been proposed for the formation of the sulphenylamide intermediate and the subsequent reactivation of the catalytic site. In the current work, the proposed mechanisms have been investigated by the use of density functional theory calculations. Our results suggest that these two mechanisms have similar overall energy barriers and that the preferred route will be determined by the availability of hydrogen peroxide or other oxidizing reagents.     

6H－1，2－氧硫杂环己烷并［5，6－c］异苯并吡喃类衍生物的合成及其抗炎活性

６Ｈ－１，２－氧硫杂环己烷并［５，６－ｃ］异苯并吡喃类衍生物的合成及其抗炎活性王进军，崔昌亿，韩光范，魏永慧，姜贵吉（吉林化工学院精细化工系吉林１３２０２２）（吉林医学院检验系吉林）（延边大学化学系延吉）关键词异苯并二氢吡喃，杂环化合物，抗炎活性可用...     

Hydrothermal synthesis, crystal structures and luminescent properties of two new Ln(III)–succinate (Ln=Eu, Tb) complexes exhibiting three dimensional networks

Two new coordination polymers, [Eu₂(L)₃(H₂O)₂]_n 1 and {[Tb₂(L)₃(H₂O)₂]·H₂O}_n 2, (H₂L=succinic acid) have been synthesized by the reaction of H₂L with nitrate salts of Eu(III) or Tb(III) under hydrothermal conditions. The X-ray diffraction analysis reveals that the two complexes are constructed by L bridging the chains of edge-sharing EuO₈(H₂O) or TbO₈(H₂O) polyhedra to form 3D network structure. 1 and 2 possess different topological structures due to the difference in the conformations of L. The solid photoluminescence of 1 and 2 was also investigated in room temperature.     

Disposable ionic liquid coating for headspace solid-phase microextraction of benzene, toluene, ethylbenzene, and xylenes in paints followed by gas chromatography-flame ionization detection

Solid-phase microextraction (SPME) with a disposable ionic liquid (IL) coating was developed for headspace extraction of benzene, toluene, ethylbenzene, and xylenes (BTEX) in paints. The SPME fiber was coated with IL prior to every extraction, then the analytes were extracted and desorbed on the injection port of gas chromatography, and finally the IL coating on the fiber was washed out with solvents. The coating and washing out of IL from the fiber can be finished in a few minutes. This disposable IL-coated fiber was applied to determine BTEX in water-soluble paints with results in good agreement with that obtained by using commercially available SPME fibers. For all the four studied paints samples, the benzene contents were under the detection limits, but relatively high contents of toluene, ethylbenzene and xylenes (56-271 microg g(-1)) were detected with spiked recoveries in the range of 70-114%. Compared to the widely used commercially available SPME fibers, this proposed disposable IL-coated fiber has much lower cost per determination, comparable reproducibility (RSD < 11%), and no carryover between each determination. Considering that IL possess good extractability for various organic compounds and metals ions, and that task-specific IL can be designed and synthesized for selective extraction of target analytes, this disposable IL coating SPME might has great potential in sample preparation.