漆树漆酶催化氧化对苯二胺反应的微量热法研究

在厌氧条件下，０．１ｍｏｌ／Ｌ的磷酸盐缓冲溶液（ｐＨ＝７．４）中，用微量热法测定了２９８．１５Ｋ时漆树漆酶与对苯二胺反应的摩尔反应焓ΔｒＨｍ＝－１６３．３６±０．３６ｋＪ／ｍｏｌ，米氏常数Ｋｍ＝５．５８×１０－３ｍｏｌ／Ｌ和表观一级反应速率常数ｋ１＝８．６３×１０－３ｓ－１，及此条件下用对苯二胺作底物时的漆酶活性值ＥＡ＝０．０４５ＩＵ．还利用阿伦尼乌斯经验公式计算了该反应的表观活化能，并讨论了酶－底复合过程的结合能ΔＧ０的计算．     

植物病毒病化学防治剂的探寻──Ⅲ．2，4－二氧六氢－1，3，5－三嗪N－酰基取代化合物的合成

以２，４－二氧六氢－１，３，５－三嗪为先导化合物，引入不同的酰基，进行Ｎ－酰化结构改造，合成了７个新化合物，抗病毒活性测试表明，其中４个化合物对ＴＭＶ的抑制率达到５０％～５３％，与参照物ＤＡＤＨＴ接近．     

催化抗体及其在化学中的应用

对一类新的有机反应催化剂——催化抗体作了介绍．它能提高速率１０３～１０６倍．许多有机反应，甚至那些在一般条件下很难发生的反应都能被特定的抗体所催化，并可进行克量级合成     

Interaction of an intense laser field with a dielectric containing metallic nanoparticles

In order to understand the role played by nanodefects in optical breakdown of dielectrics, the interaction of an intense laser field with model dielectric samples containing metallic nanoparticles is studied both theoretically and experimentally. A theoretical study of the metal conduction electrons dynamics in the laser field predicts an efficient injection of carriers from the metallic inclusion to the conduction band of the dielectric, which leads to a strong local increase of the optical absorption in the initially transparent matrix. This prediction is tested experimentally by using time-resolved spectral interferometry to measure excitation densities as a function of the laser intensity in silica samples doped with gold nanoparticles, which are compared with similar measurements in pure silica. PACS 61.80.Ba; 42.70.-a; 78.47.+p     

Titanium and carbon implantation of iron

Pure iron foils have been implanted with Ti and with Ti plus C and characterized by conversion electron Mössbauer spectroscopy (CEMS) and Auger electron spectroscopy (AES). Both paramagnetic and magnetic phases are observed and attributed to amorphous Fe?Ti?C alloys of differing Ti and C contents. Estimates of the thicknesses of the amorphous layers based on the CEMS data are in good agreement with the AES concentration depth profiles.     

Ar3H＋中多体势能拆分的从头计算分析

使用从头算的方法计算了Ar3H＋的稳定构型及红外振动基频，并与Ar2H＋的稳定结构及红外振动频率作了对比，讨论了二者之间的联系与差别.对Ar3H＋一个特殊构型下的势能线作了扫描，在此势能线下将Ar3H＋的四体势能拆解为两体，半三体及三体势能的加和，初步探讨了高阶势能分解为低阶势能的最佳途径.     

Comparison of Carboxylic and Hydroxycarboxylic Acids as Complexing Agents for Transition Metal Separation with Nonaqueous Capillary Electrophoresis

Many papers have been published on the analysis of metal cations by capillary electrophoresis (CE), for example, lanthanide, transition metal, alkali, and alkaline earth metal ions. Separations of metal ions are based on the differences in their electrophoretic mobilities. Since most     

Development of Dipolar Proton Transfer Reaction Mass Spectrometer for Real-time Monitoring of Volatile Organic Compounds in Ambient Air

Volatile organic compounds (VOCs) in ambient air can participate in photochemical reactions, which lead to the generation of secondary pollutants such as ozone and aerosol. So real-time and accurate monitoring of atmospheric VOCs plays an important role in the study of the causes of air pollution. On the basis of proton transfer reaction mass spectrometry (PTR-MS) research, a novel dipolar proton transfer reaction mass spectrometer (DP-PTR-MS) for real-time and on-line monitoring of atmospheric VOCs was developed. Compared with conventional PTR-MS with one kind of reagent ion H₃O⁺, DP-PTR-MS had three kinds of reagent ions H₃O⁺, OH^?, (CH₃)₂COH⁺, which could be switched according to the actual detection need. So DP-PTR-MS can improve the qualitative ability and expand the detection range effectively. The reagent ion H₃O⁺ can be used for detecting VOCs whose proton affinities are greater than that of H₂O. The reagent ion OH^? can be used to identify VOCs cooperating with the reagent ion H₃O⁺, and can also be used for detecting some inorganic substances such as CO₂. The reagent ion (CH₃)₂COH⁺ can be used for accurately detecting NH₃ under interference elimination circumstances. The limit of detection (LOD) and sensitivity of DP-PTR-MS were measured by using six kinds of standard gases. The results showed that the LOD for detecting toluene was 7 × 10^?12 (V/V) and the sensitivity for detecting ammonia reached 126 cps/10^?9 (V/V). The ambient air in Hefei city was on-line and real-time monitored for continuous 78 h with DP-PTR-MS. The results showed that the newly developed DP-PTR-MS could be used for long-term and real-time monitoring atmospheric VOCs at the concentration of 10^?12 (V/V) level. DP-PTR-MS is an important tool to the study of the causes of atmospheric pollution and the monitoring of trace VOCs emissions.     

Fast determination of β-endosulfan, α-hexachlorocyclohexane and pentachlorobenzene in the river water from northeast of China

A magnetic solid-phase extraction method for the preconcentration of three organochlorine pesticides (OCPs) from water samples has been proposed, based on magnetic phosphatidylcholine (MPC) as adsorbents. The extraction procedure was carried out in a single step by stirring the mixture of MPC and water samples. Subsequently, the MPC was collected by an external magnetic field without additional centrifugation or filtration. The analytes were desorbed from the MPC and finally analysed by gas chromatography–tandem mass spectrometry. The influence of various parameters on OCPs recoveries was studied. Results show that phosphatidylcholine amount and extraction time were critical in enhancing extraction performance, and the presence of humic acid was shown to significantly reduce the extraction efficiency. The limits of detection obtained were in the range of 0.1–0.15 ng L^?1. Recoveries of spiked water samples ranged from 76.2% to 101.5% with relative standard deviations varying from 3.8% to 7.7%. The proposed method was employed for analysis of pentachlorobenzene, α-hexachlorocyclohexane and β-endosulfan in the surface water from two rivers in northeast China.     

A comparative study on in vitro cytotoxicity,cellular uptake,localization and apoptosis-inducing mechanism of two ruthenium(II) complexes

Two ruthenium complexes [Ru(MeIm)₄(bpy)]²⁺ (Ru1, MeIm = 1-methylimidazole, bpy = 2,2′-bipyridine) and [Ru(Im)₄(bpy)]²⁺ (Ru2, Im = imidazole) with the same PF ₆ ^? counter-ion but different lipophilicities were synthesized and characterized and as potent anticancer agents. The relationships between cellular uptake, localization and molecular action mechanisms of these complexes were elucidated. The results showed that Ru1 with higher logP_o/w exhibited faster cellular uptake rates, but lower anticancer activity than Ru2. In addition, Ru1 predominantly accumulated in the mitochondria and cytoplasm, and induced G0/G1 cell cycle arrest, whereas the more hydrophilic Ru2 tended to localize and accumulate in the cell nucleus and mitochondria. Further mechanism studies indicated that Ru2 caused cell cycle arrest at S phase by regulating cell cycle related proteins and induced apoptosis in A549 cells through DNA damage, cellular ROS accumulation, activation of the caspase pathway and mitochondrial dysfunction.