Trace determination of hexabromocyclododecane diastereomers in water samples with temperature controlled ionic liquid dispersive liquid phase microextraction

A novel temperature controlled ionic liquid dispersive liquid phase microextraction(TCIL-DLPME) coupled with rapid resolution liquid chromatography-electrospray tandem mass spectrometry(RRLC-ESI-MS-MS) has been developed for the enrichment and determination of three hexabromocyclododecane diastereomers(HBCDs) in water samples.Green solvent ionic liquid(IL) was used as extraction solvent instead of toxic organic solvents.This technique also avoided the usage of dispersive solvent.Some important parameters that might affect the extraction efficiency were optimized.Under the optimum conditions,good linear relationship,sensitivity and reproducibility were obtained.All the limits of detection for the three diastereomers were 0.1 ng/ mL.The linear range was obtained in the range of 1-100 ng/mL for the total amount of three HBCD diastereomers.It was satisfactory to analyze real environmental water samples with the recoveries ranging from 77.2%to 99.3%.The main advantage of the method is toxic organic solvent-free.     

无气味代硫醇试剂的合成与应用研究进展

综述了无气味硫醇和硫化试剂的合成及其作为代硫醇试剂在有机合成中应用的研究进展.     

Tracing the evolution of the mitochondrial protein import machinery

Mitochondria are eukaryotic organelles originated from a single bacterial endosymbiosis about 2 billion years ago. One of the earliest events in the evolution of mitochondria was the acquisition of a mechanism that facilitated the import of proteins from cytosol. The mitochondrial protein import machinery consists of dozens of subunits, and they are of modular design. However, to date, it is not clear when certain component was added to the machinery. Using extensive homology searches, the evolutionary history of the mitochondrial protein import machinery was reconstructed. The results indicated that 6 of the 35 subunits have homologs in prokaryote, suggesting that they were prokaryotic origin; the major subunit gains were occurred in the earliest stage of eukaryotic evolution; subsequent to the gain of these conserved set of subunits, the mitochondrial protein import machinery components diversified along the eukaryotic lineages and a number of lineage-specific subunits can be observed. Furthermore, protein import systems of mitochondria-like organelles (hydrogenosomes and mitosomes) have dramatically reduced their subunit contents, however, they share most of the prokaryotic origin components with mitochondrion.     

Adsorption of 2,4,6-trinitrotoluene on Al(111) ultrathin film: periodic DFT calculations

The adsorption of 2,4,6-trinitrotoluene (TNT) molecule on the Al(111) ultrathin film were investigated by the generalized gradient approximation (GGA) of density functional theory (DFT). The calculations employ a supercell (4 × 4 × 2) model and three-dimensional periodic boundary conditions. The strong attractive forces between oxygen and aluminum atoms induce the N–O bond breaking of the TNT. Subsequently, the dissociated oxygen atoms and radical fragment of TNT oxidize the Al ultrathin film. The N–O bond of the o-NO₂ group is easier to rupture than that of the p-NO₂ group after the adsorption of the TNT molecule on the Al(111). Except for the breaking of the N–O bonds of the nitro group, other bonds of TNT molecule do not dissociate. The largest adsorption energy is −747.3 kJ/mol. The most of charge transfer is 3.42 e from the Al(111) to the fragment of TNT molecule. The aluminum ultrathin film is readily oxidized by the radical fragment of TNT, which is initiated by the dissociated O atoms from the nitro group.     

一例新型桥联吡啶化合物的合成和结构研究

利用改进的Sonogashira反应一锅法合成了一例未见报道的叁键桥联的联吡啶类化合物L[2,6-二(3'-吡啶乙炔基)-4-甲基苯胺],与常规的分步合成方法相比,新方法不需脱除保护,从而简化了反应步骤,提高了产率.对所合成的化合物利用红外、核磁、元素分析等确定了其结构,并进一步利用X射线单晶衍射法测得了该化合物的单晶结构.单晶分析显示该化合物结晶于正交晶系、Pca21空间群中,a=10.178A,b=10.972A,c=28.949 A;a=β=γ=90°,Z=8.该化合物在配位化学方面具有潜在的应用前景.我们测定了其固态下的荧光性质,显示其能够发出较强的蓝色光.     

Ce-TiO_x超细粒子的模板法制备及结构研究

利用模板法结合真空干燥技术制备出Ce-TiOx超细粒子,用XRD,TG-DSC,TEM等手段进行表征;以甲基橙溶液的光催化降解测试Ce-TiOx超细粒子的催化活性;考察初始物质的量比及热处理温度对Ce-TiOx超细粒子的结构及光催化活性的影响。结果显示:钛干凝胶经400℃热处理可得结晶度较高的锐钛矿型TiO2,800℃时TiO2转变为金红石相;Ce-Ti干凝胶经800℃热处理可得粒径约为45 nm的类球形颗粒;Ce-TiOx超细粒子中,钛以Ti3O5,Ti6O11,TiO2等多种形式存在,铈以CeO2和Ce7O12的形式存在;稀土铈影响Ce-TiOx超细粒子中钛的价态。     

泽泻醇类化合物与血清白蛋白相互作用的分子机理研究

中药泽泻具有抗肿瘤作用,可能与血清中蛋白成分的改变有关.利用荧光光谱、圆二色谱结合分子模拟技术研究了模拟生理条件下泽泻有效成分泽泻醇类化合物与人血清白蛋白的相互作用.实验结果表明,23-乙酰泽泻醇B与蛋白的结合作用远强于24-乙酰泽泻醇A.分子模拟结果与实验一致,并且表明,结合强弱的差异与小分子的侧链结构有关.该结果可...     

Synthesis and biological evaluation of novel benzothiazole-2-thiol derivatives as potential anticancer agents

A series of novel benzothiazole-2-thiol derivatives were synthesized and their structures determined by 1H-NMR, 13C-NMR and HRMS (ESI). The effects of all compounds on a panel of different types of human cancer cell lines were investigated. Among them, pyridinyl-2-amine linked benzothiazole-2-thiol compounds 7d, 7e, 7f and 7i exhibited potent and broad-spectrum inhibitory activities. Compound 7e displayed the most potent anticancer activity on SKRB-3 (IC(50) = 1.2 nM), SW620 (IC(50) = 4.3 nM), A549 (IC(50) = 44 nM) and HepG2 (IC(50) = 48 nM) and was found to induce apoptosis in HepG2 cancer cells.     

A structurally ordered thiophene-thiazole copolymer for organic thin-film transistors

This paper reports a new donor-acceptor copolymer semiconductor, PTBTh, comprising bithiophene and bithiazole where the regular coplanar structure and the intramolecular charge transfer are expected to increase the opportunity for --- stacking and charge transport. The AFM image shows lamellar stacking of the polymer on the surface. The field-effect transistor (FET) properties of PTBTh have been evaluated by a bottom-contact/bottom-gate TFT configuration. The device showed a high hole mobility of 1.14×10-2 cm2 V-1 s-1 and a current on/off ratio of 3×105 with the polymer thin film annealed at a mild temperature of 120 ℃ when measured under ambient conditions.