A Competitor-switched Electrochemical Sensor for Detection of DNA

A competitor‐switched electrochemical sensor based on a generic displacement strategy was designed for DNA detection. In this strategy, an unmodified single‐stranded DNA (cDNA) completely complementary to the target DNA served as the molecular recognition element, while a hairpin DNA (hDNA) labeled with a ferrocene (Fc) and a thiol group at its terminals served as both the competitor element and the probe. This electrochemical sensor was fabricated by self‐assembling a dsDNA onto a gold electrode surface. The dsDNA was pre‐formed through the hybridization of Fc‐labeled hDNA and cDNA with their part complementary sequences. Initially, the labeled ferrocene in the dsDNA was far from surface of the electrode, the electrochemical sensor exhibited a "switch‐off" mode due to unfavorable electron transfer of Fc label. However, in the presence of target DNA, cDNA was released from hDNA by target DNA, the hairpin‐open hDNA restored its original hairpin structure and the ferrocene approached onto the electrode surface, thus the electrochemical sensor exhibited a "switch‐on" mode accompanying with a change in the current response. The experimental results showed that as low as 4.4×10⁻¹⁰ mol/L target DNA could be distinguishingly detected, and this method had obvious advantages such as facile operation, low cost and reagentless procedure.     

Photodegradation of Rhodamine B on Sulfur Doped ZnO/TiO2 Nanocomposite Photocatalyst under Visible-light Irradiation

Sulfur doped ZnO/TiO₂ nanocomposite photocatalysts were synthesized by a facile sol‐gel method. The structure and properties of catalysts were characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), UV‐vis diffusive reflectance spectroscopy (DRS) and N₂ desorption‐adsorption isotherm. The XRD study showed that TiO₂ was anatase phase and there was no obvious difference in crystal composition of various S‐ZnO/TiO₂. The XPS study showed that the Zn element exists as ZnO and S atoms form SO^2?₄. The prepared samples had mesoporosity revealed by N₂ desorption‐adsorption isotherm result. The degradation of Rhodamine B dye under visible light irradiation was chosen as probe reaction to evaluate the photocatalytic activity of the ZnO/TiO₂ nanocomposite. The commercial TiO₂ photocatalyst (Degussa P25) was taken as standard photocatalyst to contrast the prepared different photocatalyst in current work. The improvement of the photocatalytic activity of S‐ZnO/TiO₂ composite photocatalyst can be attributed to the suitable energetic positions between ZnO and TiO₂, the acidity site caused by sulfur doping and the enlargement of the specific area. S‐3.0ZnO/TiO₂ exhibited the highest photocatalytic activity under visible light irradiation after Zn amount was optimized, which was 2.6 times higher than P25.     

Synthesis,Characterization and Thermal Behaviors of 4-Amino-5-nitro-1,2,3-triazole(ANTZ)and Its Derivatives

4‐Amino‐5‐nitro‐1,2,3‐triazole (ANTZ) and its derivatives, such as 2‐(4‐amino‐5‐nitro‐1,2,3‐trazole‐1‐yl)‐1,3,5‐trinitrobenzene (T‐ANTZ) and 4‐amino‐5‐nitro‐1,2,3‐triazole (M‐ANTZ), were synthesized and characterized, whose structures were confirmed by IR, NMR and elemental analysis. The thermal behaviors of ANTZ, T‐ANTZ and M‐ANTZ were studied by the methods of DSC and TG‐DTG, and the results showed that there is an obvious melting process of ANTZ with melting point of 278.38°C, while there is no melting process in the thermal behavior of T‐ANTZ and M‐ANTZ (the derivatives of ATNZ).     

Trition X-100/C_(10)H_(21)OH/H_2O体系层状液晶中纳米羟基磷灰石粉体的合成

本文以Triton X-100/C10H21OH/H2O体系层状溶致液晶为模板,Ca(NO3)2和(NH4)2HPO4为反应物,在一定的pH条件下,通过三元相图确定了层状液晶单相区域,并合成了羟基磷灰石(HA)纳米颗粒。用傅立叶红外光谱(FTIR),X射线衍射(XRD)和透射电子显微镜(TEM)对产物进行了表征。并考察了不同助表面活性剂浓度和不同表面活性剂浓度对产物的形貌和尺寸的影响。结果表明所制备的HA纳米颗粒平均直径为8~10nm、长度在100nm左右,呈针状。助表面活性剂浓度对HA形貌及尺寸影响不大,但是在一定范围内改变表面活性剂浓度可以起到调控HA纳米颗粒形貌和尺寸的作用。     

表面活性剂胶束对MA-AA复合振荡反应的影响

化学振荡反应是一类典型的非线性现象[1-5],研究各种因素对化学振荡反应的动力学控制问题在生物和化学应用中有重要的意义[6,7].生物体系中化学振荡反应实际上是产生于溶胶中(包括高分子溶液和表面活性剂溶液)[8],因此,要模拟生物体系的化学振荡就不能不考虑溶胶对振荡反应的影响.     

蔬菜和食用菌中多种氨基甲酸酯农药残留的UPLC-MS/MS的确证方法

建立了蔬菜和食用菌中19种氨基甲酸酯农药残留的液相色谱串联质谱（UPLC-MS/MS）确证方法.实验方法采用丙酮和乙腈混合溶液提取,凝胶渗透色谱净化,经浓缩后由HPLC-MS/MS测定.实验结果表明：方法定性定量准确,灵敏度高,满足了国内外限量要求,具有较好的推广价值.回收率为70.1%~95.7%,RSD为1.63%~13.83%,方法最低检出限0.01 mg/kg.     

钼钒氧簇二聚体[Ni(enMe)_2]_4{[Ni(enMe)_2][Ni(enMe)_2(H_2O)]_2[Mo_8~(Ⅵ)V_6~(Ⅳ)O_(38)(V~ⅤO_4)]_2}·8H_2O的合成与结构表征(英文)

在水热条件下合成了一例新型的多金属氧酸盐二聚物,[Ni(enMe)2]4{[Ni(enMe)2][Ni(enMe)2(H2O)]2[Mo8ⅥV6ⅣO38(VⅤO4)]2}.8H2O(1)(enMe=1,2-丙二胺),利用元素分析、红外光谱分析、粉末X射线衍射、热重分析和单晶X射线衍射表征了其结构。结果表明,化合物(1)属于单斜晶系,P2(1)/n空间群.晶胞参数为a=1.9685(4)nm,b=1.3549(3)nm,c=2.7039(5)nm,α=90°,β=93.94(3)°,γ=90°,V=7.195(2)nm3,Z=4,Dc=2.390g/cm3,Mr=2588.4,μ=3.195mm-1,F(000)=5012,最终R1=0.0743,wR2=0.1861.与此同时,(1)是第一个具有二帽-Keggin型钼钒氧簇的二聚体,它由过渡金属部分[Ni(enMe)2(H2O)]22+连接形成{[Ni(enMe)2][Ni(enMe)2(H2O)]2[Mo8ⅥV6ⅣO38(VⅤO4)]2}8-二聚阴离子.     

13顶点金属碳硼烷结构和非线性光学性质的DFT研究

采用量子化学密度泛函理论(DFT)B3LYP/6-31G(d)方法,对4,1,6-MC2B10H1213顶点金属碳硼烷几何构型进行优化,结合有限场(FF)方法计算了它们的极化率和二阶非线性光学(NLO)系数.结果表明,十个13顶点金属碳硼烷分子中1a～6a的二阶NLO系数与其构型纵向扩张呈现相同的规律.分子的前线分子轨道能级差越小,其二阶NLO系数越大.对于不同自旋态的同种金属碳硼烷分子,其偶极矩值为高自旋态大于相应的低自旋态,极化率和二阶NLO系数与自旋多重度没有一致的对应规律,自旋多重度对NLO性质影响不大.     

Investigation of a catalyst ink dispersion using both ultra-small-angle X-ray scattering and cryogenic TEM

The dispersion of Nafion ionomer particles and Pt/C catalyst aggregates in liquid media was studied using both ultra-small-angle X-ray scattering (USAXS) and cryogenic TEM. A systematic approach was taken to study first the dispersion of each component (i.e., ionomer particles and Pt/C aggregates), then the combination of the components, and last the catalyst ink. Multiple-level curve fitting was used to extract the particle size, size distribution, and geometry of the Pt/C aggregates and the Nafion particles in liquid media from the scattering data. The results suggest that the particle size, size distribution, and geometry are not uniform throughout the systems but rather vary significantly. It was found that the interaction of each component (i.e., the Nafion ionomer particles and the Pt/C aggregates) occurs in the dispersion. Cryogenic TEM was used to observe the size and geometry of the particles in liquid directly and to validate the scattering results. The TEM results showed excellent agreement.