发泡镍电极电化学还原嘌呤中间体

由三维发泡镍电极H2SO4电解质和阳离子交换膜,组成隔膜式三维发泡镍电解循环装置.利用该装置将3-甲基-4-亚氨基-5-异亚硝基脲嗪(NAU)电还原为3-甲基-4,5-二氨基脲嗪(DAU).比较发泡镍阴极的电流密度,测定不同pH条件下的反应电位.结果表明,发泡镍电极的电流密度比平板镍高77.3%～86.7%,电流效率平均90.3%,NAU还原转化率平均98.4%,电还原能耗平均2.92kWh/kg.恒电流电还原过程出现峰电位,继续延长电还原时间则有副反应产生.分别以传统铁粉还原和电还原的DAU完成下游嘌呤产品的合成,证明电还原产品收率不低于铁粉还原.     

水相模拟体系中胆红素钙的合成与表征

以水溶液作为生物模拟体系,在不同反应摩尔比条件下,合成了一系列胆红素钙,利用中、远红外光谱,多晶X射线粉末衍射谱,电感耦合等离子体发射光谱等对合成的胆红素钙进行了表征.结果表明:胆红素钙的组成在Ca(C33H34N4O6)和Ca2.4(C33H32N4O6)(H2O)0.06之间变化,具有非化学计量性质,显示了与生物矿化产物相类似的特征.不同的胆红素钙其配位情况有所不同,并且钙含量较高时形成的胆红素钙有较好的结晶态.     

单官能团物质的用量对体型缩聚凝胶点之影响

通过引入官能团的单官能团物质贡献率这一新参数，用统计的方法导出了可反映的单官能团物质的用量对体型缩聚凝胶点之影响，并可预测体系的凝胶点的新公式，同时给出了该公司的应用示例。     

菲的三维荧光光谱特性研究

多环芳烃(简称PAHs)具有高荧光量子产率,利用三维荧光光谱研究了PAHs中菲的荧光光谱特性.菲具有两个荧光峰.通过对菲的三维荧光光谱的分析,选择在激发波长255 nm、发射波长370 nm对菲进行定量分析.菲溶液在5.0～250.0 ng·mL-1的范围内工作曲线呈线性关系,检出限为3.88 ng·mL-1,相对标准偏差为4.23%(n=5),实验还尝试了对自来水样品的测定,测试效果良好,回收率为90.0%～105.4%.该研究为快速检测水源水中痕量PAHs提供了方法基础.     

Development of a ZHER3‐Affibody‐Targeted Nano‐Vector for Gene Delivery to HER3‐Overexpressed Breast Cancer Cells

Despite the initial successes of gene delivery applications, they faced on several intrinsic drawbacks including toxicity and immunogenicity. Therefore, alternative gene‐delivery systems derived from recombinant peptides have emerged and is rapidly developing. Human epidermal growth factor receptor‐3 (HER3) shows high activity in tumor resistance to anti‐human epidermal growth factor receptor 2 (HER2) therapies. In this study, an affibody molecule against HER3 is conjugated to a biomimetic peptide RALA (an amphipathic and cationic peptide enriched with arginine) and the ability of the fusion vector for targeting HER3 and afterward delivering specific genes in breast cancer cells is evaluated. The results demonstrate that the biopolymeric platform, which contains an affibody‐conjugated RALA peptide, can effectively condense DNA into nanoparticles and target the overexpressed HER3 receptors in breast cancer cells and transfer specific genes. The use of such a recombinant biopolymer may pave the way for the development of sensitive and effective diagnostic and treatment tool for breast cancer.     

Regio‐ and Stereoselective Biomimetic Synthesis of Oligostilbenoid Dimers from Resveratrol Analogues: Influence of the Solvent,Oxidant, and Substitution

Oligostilbenoids are polyphenols that are widely distributed in nature with multifaceted biological activities. To achieve biomimetic synthesis of unnatural derivatives, we subjected three resveratrol analogues to oligomerization by means of one‐electron oxidants. Upon varying the metal oxidant (AgOAc, CuBr₂, FeCl₃ ? 6 H₂O, FeCl₃ ? 6 H₂O/NaI, PbO₂, VOF₃), the solvent (over the whole range of polarities), and the oxygenated substitution pattern of the starting material, stilbenoid oligomers with totally different carbon skeletons were obtained. Here we propose to explain the determinism of the type of skeleton produced with the aid of hard and soft acid/base concepts in conjunction with the solvating properties of the solvents and the preferred alignment by the effect of π stacking.     

Dioxygen oxidation of hydrocarbons by a methane monooxygenase-like system: diiron complex-O2-Zn/HOAc-MV2+

The activation of dioxygen and incorporation into hydrocarbons have been achieved under mild conditions by a methane monooxygenase (MMO)-like system using a dinuclear iron complex [Fe₂ Dhist (OAc)₂]BPh₄.3H₂O as the model complex, zinc powder as the electron donor, HOAc as the proton source and methylviologen as the electron transfer agent. The results show that styrene is oxygenated predominantly to styrcne oxide (1 396 mol/100 mol of the Fe₂ complex), benzaldehyde (16160) and acetophenone (986), and cyclohexane to cyclohexanol (9370) and cyclohexanone (2670). EPR studies indicate that the hypervalent ironoxo spices Fe^IVFe^IV=O, derived from Fe^III Fe^III core via reduction, O₂-binding and protonation, is the active intermediate which inserts the activated oxygen atom into C—C or C—H bond giving each product. The system closely resembles MMO and its close relative hemerythrin in the aspects of reaction phenomena, EPR characteristics and product distributions. The Mn₂ analog cmplex, Fe-Zn heterodinuclear complex and mononuclear iron complex show no catalytic activity, indicating that dinuclear iron core is indespansable to catalytic activity.     

Multigrid solution of high order discretisation for three-dimensional biharmonic equation with Dirichlet boundary conditions of second kind

In this paper, we propose two compact finite difference approximations for three-dimensional biharmonic equation with Dirichlet boundary conditions of second kind. In these methods there is no need to define special formulas near the boundaries and boundary conditions are incorporated with these techniques. The unknown solution and its second derivatives are carried as unknowns at grid points. We derive second-order and fourth-order approximations on a 27 point compact stencil. Classical iteration methods such as Gauss–Seidel and SOR for solving the linear system arising from the second-order and fourth-order discretisation suffer from slow convergence. In order to overcome this problem we use multigrid method which exhibit grid-independent convergence and solve the linear system of equations in small amount of computer time. The fourth-order finite difference approximations are used to solve several test problems and produce high accurate numerical solutions.