阳离子碳氟表面活性剂研究Ⅰ:水溶液中的胶束特性及生长

利用动态光散射(Dynamic Light Scattering,DLS)、瞬态电双折射(Transient Electric Birefringence,TEB)和粘度测定方法研究了部分氟代阳离子表面活性剂氟代-2-羟基十一烷基二乙羟基甲基氯化铵(diethanolheptadecafluoro-2-undecanol methylammonium chloride,C8F17CH2CH(OH)CH2NCH3(C2H4OH)2Cl,DEFUMACl)水溶液的胶束化特性.结果表明DEFUMACl的临界胶束浓度cmc为3.8 mmol·L-1.稀溶液中随着DEFUMACl浓度的增加或者无机盐NaCl的加入,DEFUMACl胶束由球形向棒状转变,其转变浓度,即第二临界胶束浓度(cmcⅡ)为0.2 mol·L-1;电导测定的反离子(Cl-)结合度为0.72.利用球形和棒状胶束模型确定的DEFUMACl胶束聚集数分别为45和335.     

多模态教学模式在“食品理化检验”中的应用

基于学生自主学习能力的培养,为更好地帮助并引导学生理解晦涩难懂、枯燥抽象的知识点,以我校卫生检验与检疫专业65名学生为研究对象,将食品理化检验课程的部分章节内容采用多模态教学模式,其余内容采用传统讲授教学模式,课程结束后使用统一问卷进行调查,对多模态教学效果进行评价。结果表明2种教学模式在理解抽象实验技术或仪器、活跃课堂气氛、拓宽学习思路以及培养学习兴趣、自主学习能力和解决实际问题能力等方面均有统计学差异(p＜0.05),且有95%的学生建议继续采用多模态教学模式。教学实践及其效果评价证明多模态教学对理解抽象问题等有一定的促进作用,并可唤起学生学习兴趣、培养学生解决实际问题的能力、拓宽学习思路等。     

Tween-20与牛血清白蛋白的相互作用

通过表面张力和等温滴定量热方法，研究了非离子表面活性剂Tween-20与牛血清白蛋白(BSA)的相互作用. 结果表明，BSA与Tween-20的相互作用较弱，当Tween-20浓度增大时，能将吸附于表面上的BSA分子取代. BSA/Tween-20混合体系的性质随温度的变化趋势与单一非离子型表面活性剂相似. BSA浓度在3.7×10^-5～11.1×10^-5 kg•L^-1范围内，Tween-20的cmc不随BSA浓度的变化而变化. 当Tween-20的含量一定时，Tween-20与BSA相互作用过程的热效应也与BSA 的浓度无关. BSA/Tween-20混合体系的热力学参数表明， BSA的存在使Tween-20的cmc减小，体系的熵变增大.     

Development of a light-up fluorescent probe for HRAS G-quadruplex DNA

The development of small-molecule G-quadruplex DNA probes has attracted significant attention in recent years. However, G-quadruplexes can display a wide variety of topologies, which process different structures and functions. Therefore, selective discrimination one G-quadruplex structure over another is promising. Herein, we reported the design, synthesis and biological evaluation of a long-chain fatty amine functionalized triphenylamine-quinolinium conjugate 1b. Significant enhancement of the fluorescence intensity (over 180 fold) was observed when 1b bound with HRAS G-quadruplex DNA, while much weaker enhancements were presented in the presence of other G-quadruplexes (45–90-fold) and single/double-stranded DNAs (less than 20-fold), indicating 1b had an excellent selectivity to HRAS. The details of the interactions were investigated by UV–Vis, FID and CD analysis. The results show 1b could interact and stabilize HRAS structure mainly by π-π stacking binding mode. The introduced amine chain of the structure core was found to be better in the terms of inducing selectivity toward G-quadruplex structure. In addition, the application of 1b as a fluorescent agent for living cell imaging was also demonstrated.     

Progresses of Magnetic Relaxation Switch Sensor in Medical Diagnosis and Food Safety Analysis

Fast and accurate detection of complex samples in either medical diagnosis or food safety analysis are of great significance for the safeguarding of human health. Magnetic relaxation switches (MRS) technique based on superparamagnetic nanoparticles (SMP) is the combination of nano-biotechnology, nuclear magnetic resonance, chemistry and immunoassay. MRS assay has the characteristics of high sensitivity and specificity, as well as nondestructive and time-saving, and can be used in turbid complex samples. In this paper, with a brief discussion about the detection theory of superparamagnetic nanosensor, the target type, structural characteristics, limit of detection, state of magnetic nanoparticles and the change of T₂ value of MRS were reviewed. The research progresses of magnetic relaxation switch sensor in medical diagnosis of different biomarkers and the analysis of food hazard factor were also summarized. Accordingly, future research targets from three aspects, e.g., preparation and modification of magnetic nanoparticles, the improvement of detection sensitivity and construction of high flux magnetic relaxation switch sensor, were put forward.     

Synthesis and Charcterzation of SilicaImmobilized Benzene-Diazo-Dmino-Azobenzene

Chelating groups can be chemically bonded to the surface of solid supports such as silica.Immobilization reations on silica are relatively simple, especially when compared to immobilization involving organic polymers. Because silica exhibits the good mechanical strength,swelling stability and the fast metal ion exchange kinetics, such materials are gaining increasing importance for the separation and enrichment of trace metal ions from dilute aqueous solution.     

Dynamic Behaviour of Self-Diffraction in Bacteriorhodopsin Film

We investigate the dependences of the diffraction efficiency of the first order self-diffracted beam in bacteriorhodopsin (bR) films on the illumination time, the intensity and wavelength of the incident light. When the blue light (λ = 488 nm) and low intensity red light (λ = 632.8 nm) are incident on the bR film respectively,the diffraction efficiencies increase from zero to a stable value with the illumination time. When the green light (λ = 533 nm) and high-intensity red light illuminate the bR film respectively, the diffraction efficiencies increase from zero to the maximum and then decrease to a stable value with the illumination time. Rise and decay times are dependent on the intensity and wavelength of the incident light. The maximal diffraction efficiency of the red light is twice as high as that of the green light. The highest diffraction efficiency of 5.4% is obtained at 633nm.The diffraction efficiency change with the time for the green light is larger than that for the blue and red light.     

Epoxidation of allyl chloride with H_2O_2 on Ti-ZSM-5 prepared by the isomorphous substitution

The epoxidation of allyl chloride with H2O2 on Ti-ZSM-5 prepared by isomorphous substitution of HZSM-5 with TiCl4 gas was studied. The results show that Ti-ZSM-5 has a high catalytic efficiency for the epoxidation of allyl chloride. The H2O2 utilization reaches 99.50% when the allyl chloride/H2O2 molar ratio is > 1. The effect of solvent species, catalyst concentration, H2O2 and allyl chloride concentration and reaction temperature on the epoxidation was investigated simultaneously. It is found that methanol is the best solvent for the reaction. The reaction rate equation with v = k[Cat. ] [H2O2]1/2-[C3H5Cl] and the apparent activation energy with Ea = 63.462 kJ/mol are obtained according to the kinetics study.     

光电催化降解活性艳红K-2BP中电解质NaCl和Na2SO4的作用研究

以TiO₂/Ti为阳极, Ti网为阴极, 研究了活性艳红K-2BP在NaCl和Na₂SO₄电解质中的降解情况, 深入探讨了两种电解质在光电催化降解染料中的作用, 研究了电解质浓度、溶液pH值的影响, 并讨论了在混合盐电解质存在下, 活性艳红K-2BP的降解行为. 研究表明, 以NaCl为电解质时, Cl^－会转化为氧化性很强的活性氯, 活性氯及光电的共同作用, 加速了染料的降解. 以Na₂SO₄为电解质时, SO₄^2－在光电的作用下将发生两类反应, 一部分SO₄^2－捕获光生空穴和HO•, 对光电催化降解染料起抑制作用; 另一部分SO₄^2－将发生反应生成H₂O₂, 对染料降解起促进作用. 关键词 光电催化; 活性艳红K-2BP; TiO₂/Ti电极; 电解质     

常温常湿CO氧化催化剂An/Fe_2O_3 的制备与稳定性研究

研究了不同方法制备的 Ａｎ／Ｆｅ２Ｏ３催化剂上常温常湿条件下 ＣＯ的氧化性能．结果表明,加料顺序、焙烧温度、沉淀剂种类、金含量等因素对催化剂的稳定性均有较大影响,其中以Ｋ２ＣＯ３或Ｎａ２ＣＯ３为沉淀剂,金含量３％,焙烧温度２５０～３５０℃ 制得的催化剂具有较好的稳定性和抗水性,于２５℃连续加入水蒸气反应４３０ ｈ可保持ＣＯ完全转化． ＸＲＤ结果表明,催化剂的稳定性与单质金及α－Ｆｅ２Ｏ３的粒径成反比,并与金和铁的化学状态有关．