Synthesis of a novel C2-symmetric thiourea and its application in the Pd-catalyzed cross-coupling reactions with arenediazonium salts under aerobic conditions

[reaction: see text] A novel thiourea-based C2-symmetric ligand was synthesized, and its application in the palladium-catalyzed Heck and Suzuki coupling reactions of arenediazonium salts was evaluated. The reactions, which were performed at room temperature, without added base, and under aerobic conditions, produced product in 4 h with good yield. The corresponding arenediazonium salts were easily generated in one step from anilines.     

石墨烯负载高活性Pd催化剂对乙醇的电催化氧化

以石墨粉为原料, 采用Hummers法液相氧化合成了氧化石墨(GO), 然后用化学一步还原制得石墨烯负载钯催化剂. X射线衍射(XRD)、透射电镜(TEM)表征表明, Pd在石墨烯载体上有较好的分散度, 粒径为3-5 nm. 电化学活性面积(EASA)、循环伏安(CV)、计时电流(CA)和计时电位(CP)等电化学测试表明, 与传统Pd/Vulcan XC-72相比, Pd/石墨烯催化剂对碱性介质中乙醇电催化氧化的催化活性有了很大的提高.     

TiO2-SiO2复合氧化物结构和红外光谱的量子化学研究

 构建了TiO2-SiO2复合氧化物晶胞结构,采用HyperChem量子化学程序中的从头计算方法以3-21G*基组对其进行了全优化计算,并进行了振动分析,预测了TiO2-SiO2复合氧化物各化学键的红外特征吸收频率. 采用IR谱对TiO2-SiO2复合氧化物进行了表征,通过理论计算与实验数据相结合的方法确定了TiO2-SiO2复合氧化物的分子结构,对其平衡几何构型、IR谱、电子结构和Lewis酸性进行了讨论.     

Binding equilibrium of I− to serum albumin with resonance Rayleigh scattering

The binding equilibrium between l^? and human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by means of the resonance Rayleigh scattering (RRS) and equilibrium dialysis. It has been found for the first time that RRS and multiple frequency scattering (MFS) are enhanced as the l^? binding to the HSA and BSA, but fluorescence quenches. The equilibrium dialysis results suggest that the binding of l^? to HSA and BSA fits a phase-distribution model other than Scatchard model, and that the order of magnitude of its phase-distribution constant was found to be 10⁴. It is most probable that Cl^? or other anion ions influence the binding of l^? by changing the ionic strength in the solution. The dialysis at different pH indicates that the binding mechanism is due to the electrostatic forces between the l^? and protonated basic amino-acid residues.     

沥青基球状活性炭气相吸脱附行为研究

本文利用热重法研究了一系列沥青基球状活性炭对蒸汽及正已烷蒸汽的动态吸脱附曲线。结果表明,PSAC对苯蒸汽的吸附及再生性能优良。随吸附温度的降低、比表面积的增大、总孔容及微孔容的增大,PSAC对苯蒸汽的吸附容量增大。PSAC对正已烷的吸附速度大于对苯蒸汽的吸附速度,但其对正已烷的平衡吸附容量小于对苯蒸汽的平衡吸附容量。     

顺式新烟碱类衍生物的三维定量构效关系研究

采用比较分子力场分析法(CoMFA)和比较分子相似性指数分析法(CoMSIA)对34个顺式新烟碱类衍生物的杀虫活性进行三维定量构效关系(3D-QSAR)研究.构建的CoMFA和CoMSIA模型的交叉验证系数rc2v分别为0.877和0.862,非交叉验证系数r2分别为0.970和0.961,表明建立的3D-QSAR模型具有较好的统计相关性和预测能力.一系列的研究结果指出:立体场、静电场和氢键受体场是描述顺式新烟碱类衍生物的化学结构与杀虫活性关系的重要参数;在咪唑啉环的3,4位不宜引入较大的取代基,提高咪唑啉环的电负性或增强硝基一个端氧的氢键受体特征有利于提高顺式新烟碱类衍生物的杀虫活性.     

氮化硼载体对 Ru-Ba/BN 氨合成催化剂性能的影响

 研究了不同方法合成的氮化硼 (BN) 的性质及其负载的 Ru-Ba 催化剂对氨合成的催化性能. 采用 X 射线粉末衍射、N2 吸附-脱附、扫描电镜和傅里叶变换红外光谱等手段对所合成的 BN 样品进行了表征. 结果表明, 采用程序升温氮化和程序升温还原法均能在低于 900 oC 的条件下合成出较纯的六方相 BN, 其比表面积分别达到 103 和 138 m2/g. 其中前者负载 Ru-Ba 的催化剂活性更高, 在 475 oC, 10 MPa 和 10 000 h–1 的条件下出口氨浓度达 7.3%, 且在 550 oC 热处理 30 h 后, 活性基本保持不变.     

食物过敏原免疫学检测技术研究进展

免疫学检测方法因特异性强、灵敏度高和操作简便的优点而备受青睐.该文介绍了部分国家和地区食物过敏原标签标注情况,食物过敏原免疫学检测技术,包括酶联免疫吸附法(ELISA)、免疫层析技术、生物传感器技术的研究进展和应用.通过与质谱、链式聚合酶反应技术(PCR)对比,探讨了食物过敏原免疫学检测技术的发展方向.     

基于Sol-gel膜和多壁碳纳米管/铂纳米颗粒增效的电流型L-乳酸生物传感器

构建了基于多壁碳纳米管(Multi-walled carbon nanotubes,MWCNTs)和铂纳米颗粒(Pt-nano)的电流型L-乳酸生物传感器。将Sol-gel膜覆盖在L-乳酸氧化酶(L-lactate oxidase,LOD)和MWCNTs/Pt-nano修饰的电极表面。实验结果表明:传感器的最佳工作条件为:检测电压0.5V;缓冲液pH6.4;检测温度25℃。此传感器的响应时间为5s,灵敏度是6.36μA/(mmol/L)。连续检测4星期其活性仍保持90%,线性范围为0.2～2.0mmol/L,且抗干扰能力强。在实际血样的检测中,此传感器与传统的分光光度法具有很好的一致性。     

Boronic Acid functionalized core-shell polymer nanoparticles prepared by distillation precipitation polymerization for glycopeptide enrichment

The boronic acid-functionalized core-shell polymer nanoparticles, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@4-vinylphenylboronic acid (poly(MBA-co-MAA)@VPBA), were successfully synthesized for enriching glycosylated peptides. Such nanoparticles were composed of a hydrophilic polymer core prepared by distillation precipitation polymerization (DPP) and a boronic acid-functionalized shell designed for capturing glycopeptides. Owing to the relatively large amount of residual vinyl groups introduced by DPP on the core surface, the VPBA monomer was coated with high efficiency, working as the shell. Moreover, the overall polymerization route, especially the use of DPP, made the synthesis of nanoparticles facile and time-saving. With the poly(MBA-co-MAA)@VPBA nanoparticles, 18?glycopeptides from horseradish peroxidase (HRP) digest were captured and identified by MALDI-TOF mass spectrometric analysis, relative to eight glycopeptides enriched by using commercially available meta-aminophenylboronic acid agarose under the same conditions. When the concentration of the HRP digest was decreased to as low as 5?nmol, glycopeptides could still be selectively isolated by the prepared nanoparticles. Our results demonstrated that the synthetic poly(MBA-co-MAA)@VPBA nanoparticles might be a promising selective enrichment material for glycoproteome analysis.