2-巯基苯并咪唑保护的铜纳米团簇的制备及银离子检测

以2-巯基苯并咪唑为保护剂,聚乙烯吡咯烷酮为稳定剂,水合肼为还原剂,“一锅法”合成2-巯基苯并咪唑保护的,高稳定性、强荧光、大斯托克斯位移的铜纳米团簇(Cu NCs),并用于检测水样中的银离子含量。采用透射电子显微镜(TEM)和X射线光电子能谱(XPS)对铜纳米团簇的结构进行表征,通过荧光光谱和紫外可见光谱对其光学性能进行研究。研究表明:该铜纳米团簇的最大激发和发射波长分别为340和558 nm,在日光灯和紫外灯下分别为无色和橙色。Cu NCs具有较高的分散性,尺寸大小为2~3 nm。在最佳反应条件下,铜纳米团簇可以选择性地被银离子猝灭,且灵敏度高,线性范围为1~40μmol/L,检测限为0.5μmol/L。该方法用于检测实际水样(自来水、湖水)中银离子的浓度,结果令人满意,表明在环境监测中有非常高的应用价值。     

An in silico ensemble method for lead discovery: decision forest

Recent progress in combinatorial chemistry and parallel synthesis has radically changed the approach to drug discovery in the pharmaceutical industry. At present, thousands of compounds can be made in a short period, creating a need for fast and effective in silico methods to select the most promising lead candidates. Decision forest is a novel pattern recognition method, which combines the results of multiple distinct but comparable decision tree models to reach a consensus prediction. In this article, a decision forest model was developed using a structurally diverse training data set containing 232 compounds whose estrogen receptor binding activity was tested at the U.S. Food and Drug Administration (FDA)'s National Center for Toxicological Research (NCTR). The model was subsequently validated using a test data set of 463 compounds selected from the literature, and then applied to a large data set with 57,145 compounds as a screening example. The results show that the decision forest method is a fast, reliable and effective in silico approach, which could be useful in drug discovery.     

Recent progress in two-photon small molecule fluorescent probes for enzymes

This review aims to provide a summary of the progress in TP small molecule fluorescent probes for enzymes in recent years and displays the main fluorescent mechanisms that have been applied to design probes.     

水溶性高聚物的研究进展

自八十年代初，水溶性高聚物再次成为高分子科学研究热点，评述了水溶性高聚物，特别是疏水缔合型改性水溶性高聚物的最新进展。     

Chemical ionization mass spectrometry of nitrosamines

The mass spectra of eight nitrosamines have been recorded, with excitation by chemical ionization (CI) and electron impact (EI). Comparison of the intensities of the base peaks under CI and El conditions gives intensity ratios in the range 1.4-1.9 for low resolution measurements and up to 10 for high resolution measurements, confirming the enhanced sensitivity available in the CI mode.     

透明导电玻璃(ITO)基材自加热传感静态芯片聚合酶链反应(PCR)

利用商品化ITO玻璃导电层的温阻效应, 无需任何微加工手段, 实现了自加热和传感的芯片温度自动程序控制, 最大程度地减小了传感滞后对温度控制稳定性的影响, 温度控制的稳定性达到了0.2 ℃, 升温速度最快可达20 ℃/s以上, 在冷却风扇辅助下降温速度最快达到了8 ℃/s. 芯片温控单元的引线从传统的两对(一对用于传感, 一对用于加热)减少为一对. 通过在该芯片上直接构建多个开放微池反应器的方法成功地实现了λDNA 157 bp片段的并行扩增. 将该芯片置于倒置荧光显微镜样品台上, 以蓝色(575 nm)发光二极管为光源, 以光电倍增管为检测手段检测了dsDNA和SYBR Green Ⅰ嵌合物的荧光强度随温度的实时变化曲线.     

Synthesis,crystal structures and magnetic properties of transition metal dicyanamide complexes coordinated with pyridyl nitronyl nitroxides

Two novel complexes Ni(NITpPy)₂[N(CN)₂]₂ · 2H₂O (I) and Zn(NITpPy)₂[N(CN)₂]₂ · 2H₂O (II) (NITpPy = 2-(p-pyridyl)-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide) were synthesized and characterized by infrared spectra, elemental analyses, and UV-Vis techniques. The crystal structures of both complexes have been determined by X-ray diffraction analysis. Both complexes are of centrosymmetric distorted octahedral co-ordination geometry in which metal ions are bound to two dicyanamide anions, two water molecules, and two radicals through the nitrogen atom of pyridine rings and show one-dimensional chain structure via hydrogen bonds. The magnetic properties of complexes I and II were investigated in the temperature range 5–300 K and discussed in detail. The two compounds exhibit weak intermolecular antiferromagnetic interaction. In complex II, the diamagnetic metal zinc just plays the role of a bridge. The article was submitted by the authors in English.     

Development of a mild mercaptoethanol extraction method for determination of mercury species in biological samples by HPLC–ICP-MS

A mild, efficient and convenient extraction method of using 2-mercaptoethanol contained extractant solution combined with an incubator shaker for determination of mercury species in biological samples by HPLC–ICP-MS has been developed. The effects of the concentration of 2-mercaptoethanol, the composition of the extractant solution and the shaking time on the efficiency of mercury extraction were evaluated. The optimization experiments indicated that the quantitative extraction of mercury species from biological samples could be achieved by using 0.1% (v/v) HCl, 0.1% (v/v) 2-mercapoethanol and 0.15% (m/v) KCl extractant solution in an incubator shaker for shaking overnight (about 12 h) at room temperature. The established method was validated by analysis of various biological certified reference materials, including NRCC DOLT-3 (dogfish liver), IAEA 436 (tuna fish), IAEA MA-B-3/TM (garfish filet), IAEA MA-M-2/TM (mussel tissue), GBW 08193 (bovine liver) and GBW 08572 (prawn). The analytical results of the reference materials were in good agreement with the certified or reference values of both methyl and total mercury, indicating that no distinguishable transformation between mercury species had occurred during the extraction and determination procedures. The limit of detection (LOD) for methyl (CH₃Hg⁺) and inorganic mercury (Hg²⁺) by the method are both as 0.2 μg L⁻¹. The relative standard deviation (R.S.D.s) for CH₃Hg⁺ and Hg²⁺ are 3.0% and 5.8%, respectively. The advantages of the developed extraction method are that (1) it is easy to operate in HPLC–ICP-MS for mercury species determination since the extracted solution can be directly injected into the HPLC column without pH adjustment and (2) the memory effect of mercury in the ICP-MS measurement system can be reduced.     

Routine determination of major anions in atmospheric aerosols by capillary electrophoresis

Capillary electrophoresis (CE) with indirect UV detection utilizing a pyromellitate-based electrolyte was used for the routine analysis of major anions in atmospheric aerosols collected on filters with high-volume (Hi-Vol) samplers. The long-term reliability of the CE system was checked over an 8-month period during which over 2900 samples were analyzed. In addition, approximately 1100 samples were analyzed in parallel by ion chromatography (IC). It has been shown that acceptable analytical performance can be routinely obtained. The agreement between the CE and IC results is good, generally better than 20% at concentrations larger than 1 mg l⁻¹.     

含苯氧基萘并萘醌和偶氮苯双变色基化合物的合成和性质

通过６－氯－５，１２－萘并萘醌与４－羟基偶氮苯及其衍生物的反应合成了３种含苯氧基萘并萘醌和偶氮苯光致变色基的双变色基化合物，６－［４－（苯偶氮基）苯氧基］－５，１２－萘并萘醌（５），６－［４－（ｐ－乙氧基苯偶氮基）苯氧基］－５，１２－萘并萘醌（６）和６－［４－（ｐ－硝基苯偶氮基）苯氧基］－５，１２－萘并萘醌（７）．这些化合物的苯氧基萘并萘醌变色基的ＵＶ诱导光致变色性较弱；基于氨与苯氧基萘并萘醌ａｎａ显色体的不可逆反应，化合物５和６ＤＭＳＯ溶液在３６５ｎｍ紫外光辐照光稳态（ＰＳＳ）下的ａｎａ醌式摩尔分数估计分别为２２％和１７％．这些结果说明，苯偶氮基对苯氧基萘并萘醌变色基的光致变色性质有着极强的影响．另一方面，与４－羟基偶氮苯母体不同，这些双变色基化合物在ＤＭＳＯ中偶氮苯变色基的顺式异构体是相对稳定的