共振瑞利散射法测定核酸的研究进展

DNA在许多生命现象和生命过程中起着决定性的作用,因此寻求快速检测DNA的方法具有重要的社会意义。本文对共振瑞利散射法分析检测DNA的研究进展进行了综述。     

两种不同粒径的SBR粒子对透明ABS树脂力学性能影响

从SBR橡胶粒子出发,采用乳液原位悬浮聚合方法合成了一系列透明ABS树脂.采用小粒径SBR橡胶粒子虽然可以获得透明性良好的透明ABS树脂,但树脂的抗冲性能较差.采用大粒径SBR橡胶粒子ABS树脂的透明性明显下降.采用由粒径分别为400nm和70nm两种SBR橡胶粒子所组成的双峰粒子(指粒度分布谱上有两个峰)体系,当二者比例在4/6~6/4范围内,总橡胶粒子含量为15%~18%时,所得到的透明ABS树脂冲击强度已经达到90~120J/m,透光率超过80%.初步探讨了不同增韧体系的ABS树脂的脆韧转变关系;研究了不同粒径橡胶粒子的协同增韧效应.确定了由SBR双峰粒子增韧体系获得具有良好力学和透光性能的ABS树脂的基本条件.     

新树型配体TTBA与铜配合物的研究

研究了新配体TTBA与二阶铜离子生成配合物的光度特征和电化学 特征。在较宽的PH范围内，新试剂和铜离子形成1：2的棕黄色配合物，并且在一定范围内具有良好的线性关系。通过电化学方法和光度法都可以证明，文中合成的新试剂氮三没食子酸三乙胺测定Cu^2 具有很高的灵敏度和选择性，在实际生产中具有一定的应用价值。     

高浓度高Al13含量聚合氯化铝溶液的制备

通过快速加碱在82 ℃下合成0.2 mol·L^-1、Al_b为60%～70%的低浓度高Al_b聚合氯化铝(L-PAC)，在热侧温度为50～95 ℃，冷侧温度约9～12 ℃的条件下进行膜蒸馏浓缩，制备出总铝浓度在2 mol·L^-1以上，Al_b含量大于90%，Al₁₃含量约为70%的高浓度高Al_b含量的聚合氯化铝溶液。对膜蒸馏浓缩过程中热侧温度、PAC的碱化度和初始pH值等因素对最终聚合氯化铝溶液产品中聚铝形态分布、总铝浓度的影响进行了初步研究，发现在热侧温度低于70 ℃、碱化度为2.47、初始pH值为5.0 ± 0.2的条件下，可以得到高浓度、高Al_b含量的聚合氯化铝溶液，纳米Al₁₃形态在较高的浓度下可以存在；低温贮存条件下，高浓度PAC中Al_b相当稳定。     

新型超分子化合物(H3NCH2CH2NH3)2[(HPO4)2Mo5O15]的晶体结构

首次通过水热方法合成了新型超分子化合物(H3NCH2CH2NH3)2[(HPO4)2Mo5O15]的晶体结构,并通过X衍射进行了结构表征,晶体学数据为:单斜晶系,C2/c空间群,a=1.766 6(4)nm,b=1.003 4(2)nm,c=1.376 7(3)nm,α=90°,β=96.90(3)°,γ=90°,ν=2.422 7(8)nm3,Z=4,R=0.043 1,wR2=0.128 7.     

N-羟基邻苯二甲酰亚胺引发的聚乙烯熔融接枝反应

研究了N-羟基邻苯二甲酰亚胺(NOP)用于引发4种卤胺类前驱单体包括甲基丙烯酰胺(MA)、N-叔丁基丙烯酰胺(N-t-BuA)、马来酰亚胺(MI)和N,N-二烯丙基三聚氰胺(NDAM)与线性低密度聚乙烯(LLDPE)的熔融接枝聚合反应,并将其与工业上普遍应用的有机过氧化物(过氧化二异丙苯,DCP)引发法作对比。在接枝效率方面,NOP的引发效率与单体的分子结构和投料量密切相关。这4种单体中,N-t-BuA的接枝效率最高,与DCP法的差异在2.5%~16.0%之间;MI的接枝效率最低,比DCP法低55%。在副反应控制方面,实时扭矩、凝胶含量和熔融指数测试证实NOP引发体系中聚乙烯交联副反应程度明显低于DCP,接枝反应更加可控。     

Amperometric Glucose Sensor with Tetrathiafulvalene as an Electron Transfer Mediator

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The inorganic cation-tailored “trapdoor” effect of silicoaluminophosphate zeolite for highly selective CO2 separation

Functional nanoporous materials are widely explored for CO₂ separation, in particular, small-pore aluminosilicate zeolites having a “trapdoor” effect. Such an effect allows the specific adsorbate to push away the sited cations inside the window followed by exclusive admission to the zeolite pores, which is more advantageous for highly selective CO₂ separation. Herein, we demonstrated that the protonated organic structure-directing agent in the small-pore silicoaluminophosphate (SAPO) RHO zeolite can be directly exchanged with Na⁺, K⁺, or Cs⁺ and that the Na⁺ form of SAPO-RHO exhibited unprecedented separation for CO₂/CH₄, superior to all of the nanoporous materials reported to date. Rietveld refinement revealed that Na⁺ is sited in the center of the single eight-membered ring (s8r), while K⁺ and Cs⁺ are sited in the center of the double 8-rings (d8rs). Theoretical calculations showed that the interaction between Na⁺ and the s8r in SAPO-RHO was stronger than that in aluminosilicate RHO, giving an enhanced “trapdoor” effect and record high selectivity for CO₂ with the separation factor of 2196 for CO₂/CH₄ (0.02/0.98 bar). The separation factor of Na-SAPO-RHO for CO₂/N₂ was 196, which was the top level among zeolitic materials. This work opens a new avenue for gas separation by using diverse silicoaluminophosphate zeolites in terms of the cation-tailored “trapdoor” effect.

The sodium form of silicoaluminophosphate RHO zeolite exhibits a pronounced cation-tailored “trapdoor” effect, showing an unprecedented selectivity adsorption separation performance for CO₂/CH₄ and CO₂/N₂.     

Inhibition of DNA polymerization and antifungal specificity of furanocoumarins present in traditional medicines

Antifungal activity is positively correlated to furanocoumarin content in extracts of the traditional phytomedicine northern prickly ash (Zanthoxylum americanum Mill. [Rutaceae]). The specificity of these furanocoumarins in inhibiting replication of DNA was investigated with reference to significant base composition differences between fungal and mammalian mitochondrial DNA. We developed a polymerase chain reaction-based assay to investigate whether (1) furanocoumarins inhibit DNA polymerization and (2) distinct furanocoumarins specifically inhibit DNA replication depending on base composition. Specific inhibition of DNA polymerization by 5-methoxypsoralen and psoralen through high-adenine and thymine (AT) (84.3%) and low-AT (51.9%) DNA, respectively, suggests that furanocoumarins inhibit replicative functions of genomes or of regions within the genome that differ in base composition. Greater overall inhibition of DNA polymerization by Z. americanum husk extracts than with single or mixed furanocoumarins suggests that inhibitory compounds in addition to the major furanocoumarins are present in Z. americanum.     

Design and Synthesis of Transparent Poly （acrylonitrile-butadiene-styrene） and Relationship Between Its Phase Construction and Transparency

IntroductionABS resins have been widely applied to the field ofengineering materials because of their excellent me-chanical,electrical,physical,and chemical proper-ties.Typically,ABS resins comprise a rigid copolymermatrix-phase dispersed in a graft copol…