流动注射化学发光法测定山奈酚

采用流动注射技术,研究了高锰酸钾-山奈酚-过氧化氢体系的化学发光行为,对影响化学发光强度的因素进行了试验,建立了流动注射化学发光法测定山奈酚的新方法.方法检出限为1×10-10g·mL-1,线性范围为1.0×10-7-1.0×10-4g·mL-1.对1.0×10-6g·mL-1的山奈酚平行测定11次,其RSD为2.1%...     

微波消解-FAAS测定6种龙胆科植物花中微量元素的含量

选用硝酸和双氧水(5∶1)的混合消解液对样品进行微波消解,采用火焰原子吸收光谱法测定了云雾龙胆,管花秦艽,线性龙胆,黄管秦艽,麻花秦艽,蓝玉簪龙胆花这6种龙胆科植物花中的Ca、Mg、Cu、Fe、Mn、Zn6种微量元素的含量。该方法的加标回收率为96.53%—100.11%,相对标准偏差(RSD)小于3%,具有良好的准确度和精密度。研究结果显示,6种龙胆科植物花微量元素含量丰富,其中Mg、Ca、Fe的含量普遍较高,不同龙胆花中各元素的含量均有一定差异。本试验为这些龙胆花药材的合理药用及进一步的开发利用提供了可靠依据。     

石墨炉原子吸收光谱法测定不同地区秦艽花中铅和镉的含量

选用硝酸和高氯酸(4∶1)的混合消解液对样品进行微波消解,利用微波消解-石墨炉原子吸收光谱法测定不同地区秦艽花药材中铅、镉的含量。该方法铅、镉加标回收率分别为96.5%、94.0%,相对标准偏差(RSD)分别为2.7%、4.3%,具有良好的准确度和精密度。结果显示,不同地区的秦艽花中Pb的含量介于1.266—3.429mg·kg-1之间,Cd的含量均小于等于0.167mg·kg-1,不同地区秦艽花中Pb、Cd的含量均有一定差异。该测定结果为秦艽花药材的质量控制与开发利用提供可靠依据。     

Characterization and Purification of the Mammalian COP9 Complex, a Conserved Nuclear Regulator Initially Identified as a Repressor of Photomorphogenesis in Higher Plants

The COP9 complex has been identified as a repressor of photomorphogenesis in Arabidopsis. Here we demonstrate that the COP9 complex is also present in mammals. Specific antibodies were generated against human counterparts of the Arabidopsis COP9 and COP11, the two known subunits of plant COP9 complex. Using these antibodies, we showed that indeed mammalian COP9 and COP11, also known as GPS1, could be coimmuno-precipitated using either of the two specific antibodies, definitively confirming that they are physically part of the same complex. Further, the mammalian COP9 and COP11/GPS1 were cofractionated in the same large molecular weight fractions of about 500 kDa and were absent from the monomeric fractions. The mammalian COP9 complex was present in all organs examined but abundances vary. Indirect immunofluorescence studies suggested that the mammalian COP9 complex is largely nuclear localized. Both conventional biochemical and affinity purifications of the COP9 complex from pig spleen indicated that the mammalian COP9 complex consists of eight distinct subunits. These findings indicate that mammals also have a COP9 complex with conserved molecular composition and biochemical and cellular properties similar to the higher plant counterpart.     

以Co2＋掺杂纳米TiO2为光催化氧化剂的原位光致化学发光分析方法 研究及其应用

研究了Co2＋掺杂TiO2纳米粒子在光信号诱导下产生的超氧阴离子自由基在纳米粒子表面的吸附和解吸特性. 当以该纳米粒子为光催化氧化剂进行原位光致化学发光反应时, 光诱导产生的超氧阴离子自由基通过扩散穿过纳米粒子表面的双电层到达本体溶液, 与溶液中的化学发光试剂进行化学发光反应. 由于超氧阴离子自由基在纳米粒子表面的吸附、解吸和双电层效应, 使得光化学反应和其后的光生氧化剂的化学发光反应具有时间和空间的分辨特性. 将 Co2＋掺杂TiO2纳米粒子光致化学发光反应的特点与鲁米诺化学发光体系结合, 建立了一种原位光致化学发光反应的新方法, 并提出了一种基于纳米技术调控化学发光反应的新思路. 在最佳反应条件下, 该方法对格列本脲响应的线性范围为2.0×10－8～1.0×10－6 g•mL－1, 检出限为6×10－9 g•mL－1.     

Asymmetric cross aldol addition of isatins with α,β-unsaturated ketones catalyzed by a bifunctional Brønsted acid–Brønsted base organocatalyst

The asymmetric cross-aldol reaction of isatins with α,β-unsaturated ketones has been developed under catalysis by a Cinchona alkaloid-derivated bifunctional Brønsted acid–Brønsted base catalyst, affording the aldol adducts in moderate to good yields (18–98%) with moderate to good enantioselectivities (30–97%). The noncovalent organo-catalyzed asymmetric cross-aldol reaction displays a broad substrate scope and wide functional-group tolerability, albeit the electronic and steric properties of both reaction partners have considerable and regular effects on the reactivity and stereocontrol.     

Lattice Bhatnagar-Gross-Krook Simulations in 2-D Incompressible Magnetohydrodynamics

Lattice Boltzmann Method is recently developed within numerical schemes for simulating a variety of physical systems. In this paper a new lattice.Bhatnagar-Gross-Krook （LBGK） model for two-dimensional incompressible magnetohydrodynamics （IMHD） is presented. The model is an extension of a hydrodynamics lattice BGK model with 9 velocities on a square lattice, resulting in a model with 17 velocities. Most of the existing LBGK models for MHD can be viewed as compressible schemes to simulate incompressible flows. The compressible effect might lead to some undesirable errors in numerical simulations. In our model the compressible effect has been overcome successfully. The model is then applied to the Hartmann flow, giving reasonable results.     

发夹型荧光分子探针用于DNA甲基化酶的活性分析及其在药物筛选中的应用

报道了一种基于发夹型荧光探针的甲基化酶活性的分析方法, 甲基化酶和相应的限制性内切酶的识别位点被设计在发夹型探针的茎部, 四甲基罗丹明(TAMRA)被连接在探针的5'端, 其荧光被连在3'端的熄灭基团4-(4'-二甲基对胺基偶氮苯)苯甲酸(DABCYL)所熄灭. 限制性内切酶可切割未发生甲基化修饰的探针, 导致探针的发夹结构遭到破坏, 引起TAMRA荧光信号的恢复. 根据荧光信号的恢复程度可实现对甲基化酶活性的分析. 在此基础上, 建立了一种简便、快速分析抗肿瘤药物对DNA甲基化酶活性的影响的方法, 为筛选针对基因甲基化异常引起的恶性肿瘤的治疗药物提供了一种新的思路和方法.     

含有机配体的活性双过氧钒配合物与组氨酸的相互作用研究

在合成和表征了4种具有较强生物活性双过氧钒配合物K_3[VO(O_2)_2(ox)]· 2H_2O，Na[VO(O_2)_2(bipy)]·5H_2O，K[VO(O_2)_2(phen)]·3H_2O和K_2[VO (O_2)_2(pic)]·2H_2O[分别缩写为pV(ox)，pV(bipy)，pV(phen)和pV(pic)，其中 ox为草酸根，bipy为2,2'-联吡啶，phen为邻菲咯啉，pic为2-羧酸吡啶负离子]的 基础上，利用多种NMR技术和电喷雾质谱（ESI-MS）研究了这4种含有机配体双过氧 钒酸合物与组氨酸（His）在溶液中的相互作用以及反应物浓度、时间、pH等对相 互作用体系的影响。~(51)V NMR跟踪监测的结果表明：双过氧钒配合物pV(ox)和 pV(pic)与His在中性水溶液中存在强配位相互作用，而pV(bipy)和pV(phen)与His 在中性水溶液中无明显作用。我们还利用谱学方法确定了pV(ox)和His相互作用后 所生成产物是pV(ox)分别与His在中性水溶液中无明显作用。我们还利用谱学方法 确定了pV(ox)和His相互作用后所生成产物是pV(ox)分别与His咪唑基上的3-N和1- N配位的一对异构体。     

Time calibration for the end cap TOF system of BESⅢ

The time calibration for end cap TOF system of BESⅢ is studied in this paper.It has achieved about 110 ps time resolution for muons in dimu events.The pulse height correction using electronic scan curve and the predicted time calculated using Kalman filter method are introduced.This paper also describes the study of using electrons and muous as calibration samples.