聚合-β-环糊精作手性选择剂的毛细管电泳法分离4种光学活性农药中间体

以聚合-β-环糊精作为毛细管区带电泳手性选择剂,成功分离了2-苯氧丙酸(PPA)、顺式-功夫菊酸(cis-PA)、1-苯基-2-(对甲苯基)乙胺(PTE)和1-苯基-2-(对甲氧基苯基)乙胺(PME)4种光学活性农药中间体的对映体。考察了不同手性选择剂及其浓度、背景电解质的pH等操作条件对分离的影响。结果表明,在12kV操作电压下、30mmol／Ltris-HCl背景电解质中,用14g／L聚合-β-CD作为手性选择剂,PPA和cis-PA对映体在pH6．0时,PIE和PME对映体分别在pH2．5和pH3．0时可以被较好分离。在优化的分离条件下,用聚合-β-CD作毛细管区带电泳手性选择剂分离PIE对映体的分离度为1．513,成功测定了两种旋光性PIE的对映体过量值。     

Identification of Different Cobalt Nucleation on Glassy Carbon

The nucleation mechanisms of cobalt from sulfate solutions were studied by utilizing the electrochemical technique, chronoamperometry. It was found that the recorded current-time transients introduced from 1.0mol/L CoSO4 solution were complexes with unusual shapes. All characteristic features were identified as separate process. The instantaneous or progressive nucleation with 2D or 3D growth exists during the cobalt deposition, depending on the applied potentials.     

Virtual screening of novel noncovalent inhibitors for SARS-CoV 3C-like proteinase

The SARS coronavirus 3C-like proteinase is considered as a potential drug design target for the treatment of severe acute respiratory syndrome (SARS). Owing to the lack of available drugs for the treatment of SARS, the discovery of inhibitors for SARS coronavirus 3C-like proteinase that can potentially be optimized as drugs appears to be highly desirable. We have built a "flexible" three-dimensional model for SARS 3C-like proteinase by homology modeling and multicanonical molecular dynamics method and used the model for virtual screening of chemical databases. After Dock procedures, strategies including pharmocophore model, consensus scoring, and "drug-like" filters were applied in order to accelerate the process and improve the success rate of virtual docking screening hit lists. Forty compounds were purchased and tested by HPLC and colorimetric assay against SARS 3C-like proteinase. Three of them including calmidazolium, a well-known antagonist of calmodulin, were found to inhibit the enzyme with an apparent K(i) from 61 to 178 microM. These active compounds and their binding modes provide useful information for understanding the binding sites and for further selective drug design against SARS and other coronavirus.     

Thermochemistry of the complexes of chromium nitrate with l-a-amino acids

The solid complexes of Cr(NO₃)₃ with L-α-amino acids (AA=Val, Leu, Thr, Arg, Phe and Try) have been prepared in 95% alcoholic, the compositions of which were identified as the general formula Cr(AA)₂(NO₃)₃·2H₂O by elemental and chemical analyses. The bonding characteristics of the title complexes were characterized by IR, indicating that nitrogen and oxygen atoms in the ligands coordinated to Cr³⁺ in a bidentate fashion. With the aid of TG-DTG and IR techniques, the complexes were subjected to thermal decomposition in an atmosphere of oxygen, presuming that the decompositions of the complexes consist of two steps and the complexes were decomposed into chromium hemitrioxide after undergoing dehydration and skeleton splitting of the complexes. The constant volume energies of combustion of the complexes were determined by a RBC-P type rotating-bomb calorimeter. According to Hess's law, the standard enthalpies of formation of the complexes were calculated as (-1831.40±4.40), (-2542.03±6.13), (-1723.81±3.99), (-2224.31±3.02), (-2911.61±6.53) and (-659.32±7.42) kJ mol^-1, respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

甲烷部分氧化制合成气的钙钛矿型致密透氧膜反应器的数值模拟(英文)

采用等温理论模型,以甲烷催化氧化制合成气为模型反应,模拟非担载钙钛矿型致密透氧膜反应器的性能。分别研究了Ｌａ_０．２Ｂａ_０．８Ｆｅ_０．８Ｃｏ_０．２Ｏ_(３－δ)、Ｌ３０．２Ｓｒ０．８Ｆｅ０．８Ｃｏ０．２Ｏ３－δ和ＳｒＦｅＣｏ０．５Ｏｘ三种透氧速率不同的膜材料、膜反应器的尺寸以及反应工艺条件对ＣＨ４转化率、ＣＯ选择性和Ｈ２／ＣＯ摩尔比的影响,对膜反应实验具有指导意义。     

新的手性双膦配体的合成及其在苯乙烯不对称氢酯基化中的应用

以甘露醇和山梨醇为原料,合成了2个新的手性膦配体,并用这些新的手性膦配体与钯原位生成的催化剂体系催化苯乙烯的不对称氢酯基化反应,得到R构型的2－苯基丙酸甲酯,其ee值分别为28.5%和13.6%。     

血管紧张素转化酶活性抑制剂──丝素肽的分离、纯化和结构鉴定

 可溶性丝素粉末经碱性蛋白酶Alcalase水解后 ,其酶解产物对血管紧张素转化酶 (ACE)的活性有很强的抑制作用。采用凝胶过滤色谱SephadexG 15和反相高效液相色谱 (RP HPLC)对水解度为 2 0 %的酶解产物进行分离纯化 ,利用质谱鉴定其中一种ACE抑制剂是肽 ,其结构为Gly Tyr。     

循环流动固定床光催化反应器动力学数学模拟

以甲基橙为模型反应物,研究了连续循环固定床光催化反应器的动力学过程.根据光催化氧化过程特点,分析并建立了准一级反应动力学方程,对该反应系统的动力学过程进行动态数学模拟,用四阶Runge-Kutta法进行数值计算,结果表明数学模拟与实验数据相吻合.在该光催化反应体系中,处理量增加时实际反应速率常数k基本不变,而表观反应速率常数kapp变小,二者之间关系与反应器体积对处理量体积比（γ）密切相关;反应速率常数受起始浓度影响很大,在15～150 μmol•L－1浓度范围内,lnk=－0.48ln[c0]＋1.42;反应速率常数与光强的关系为k∝I0.5;反应速率常数受溶液pH值的影响也很大.     

分子动力学研究V82A和L90M变异对HIV PR-IDV复合物的影响

为了说明V82A和L90M变异对蛋白酶(PR)和茚地那韦(IDV)复合物的影响,进行了5.5ns的MD模拟.用MM-PBSA方法计算了体系的结合自由能,计算和实验结果一致.分解自由能为不同能量项说明,这两个变异引起熵的贡献变化大于焓的贡献变化.分解自由能到每个残基说明Wild,V82A和L90M具有相似的结合模式,结合能的贡献主要来源于A28/A28',I50/I50'和I84/I84'这六个残基组,详细分析了Wild和IDV的结合模式,对比分析了V82A和L90M变异引起结合模式的细小变化.V82A变异引起结合模式的变化是由于变异后位阻减小导致的.L90M变异引起D25和L90间的作用增强并引起结合模式的细小变化.研究结果有助于更好地理解变异对抑制剂和HIV-1PR结合模式的影响,并可以用来帮助设计更高效的PR抑制剂.     

外偶极电场作用下H_2O,D_2O和T_2O的可逆分解电压

采用密度泛函B3P86方法和6-311++G(3df,3pf)基组,计算了在-0.05～0.05a.u.外偶极电场作用下,H2O,D2O,T2O,H2,D2,T2,O2的电子能量、核运动能量和熵值,在此基础上通过计算H2O(g)→H2(g)+O2(g)、D2O(g)→D2(g)+O2(g)、T2O(g)→T2(g)+O2(g)的焓变ΔH、熵变ΔS、Gibbs函数变化ΔG,最后得到了H2O,D2O,T2O的可逆分解电压Er.计算结果表明,外偶极电场存在时,H2O,D2O,T2O的Gibbs自由能变ΔG和可逆分解电压Er都有明显的变化,当外偶极电场正方向增加时,其Gibbs自由能变ΔG和可逆分解电压Er均趋于线性增加;当外偶极电场负方向增加时,其Gibbs自由能变ΔG和可逆分解电压Er均趋于线性减小;在相同外偶极电场作用下,Gibbs自由能变ΔG和可逆分解电压Er随H2O,D2O,T2O依次增加.