辛巴蓝F-3GA修饰的啤酒废酵母菌亲和吸附溶菌酶

利用j嗪染料辛巴蓝F-3GA修饰经戊二醛交联的啤酒废酵母菌,得到一种新型染料亲和吸附剂.辛巴蓝F-3GA的固载量为161.1 mg/g.以溶菌酶为研究对象,考察吸附时间、酶初始浓度、pH值、离子强度等因素对吸附率的影响.结果表明:当pH=7.0时,其对溶菌酶有较高的吸附量(229.1 mg/g),吸附性能明显优于未接枝...     

Numerical model for the investigation of countercurrent chromatography

A numerical model is developed to describe the separation process of countercurrent chromatography (CCC) in this work. The theory of countercurrent extraction table (TCCET) is first proposed to calculate concentration distributions of chemical components in the CCC, which is essential for a numerical model to describe the dynamic equilibrium of mass transfer. According to the theory of countercurrent extraction, the concentration in chromatography obeys binomial distribution, while the outflow from the n-th stage is a negative binomial distribution. As a result of the central limit theorem, they will obey normal distribution for sufficiently large n. Row-stage ratio (R(RS)) is then defined to determine the K value or retention time because it has a linear relationship to K value and retention time. The stage for a certain K value can be subsequently obtained with a very simple form, n(k)=1/(2piq(k)X(2)(k, max)), which can be calculated from the peak height obtained from experiments. Finally, the actual stage for a separation chromatogram can be acquired with using this simple expression. The agreement between theoretic and experimental results is quite satisfactory in the normal-phase and reversed-phase elution mode.     

脱氧雪腐镰刀菌烯醇与溶菌酶相互作用的研究

利用荧光猝灭、紫外光谱(UV)、傅里叶变换红外光谱(FTIR)和圆二色性光谱(CD)法测定反应的结合常数、主要作用力以及脱氧雪腐镰刀菌烯醇对溶菌酶二级结构的影响;并综合实验所得的热力学参数结果,确定二者间的作用力。脱氧雪腐镰刀菌烯醇与溶菌酶有较强的结合,脱氧雪腐镰刀菌烯醇对溶菌酶的荧光猝灭以氢键和范德华力为主,结合位置与色氨酸残基间的距离r为4.62nm。通过光谱法研究模拟生理条件下真菌毒素脱氧雪腐镰刀菌烯醇与溶菌酶的相互作用,为脱氧雪腐镰刀菌烯醇在体内的储存、运输及毒性机制提供一些具有指导作用的信息。     

Spatio-temporal expression of a novel neuron-derived neurotrophic factor (NDNF) in mouse brains during development

Background  

Neuron-derived neurotrophic factor (NDNF) is evolutionarily well conserved, being present in invertebrate animals such as the nematode, Caenorhabditis elegans, as well as in the fruit fly, Drosophila melanogaster. Multiple cysteines are conserved between species and secondary structure prediction shows that NDNF is mainly composed of beta-strands. In this study, we aimed to investigate the function of NDNF.     

在化学教学中培养学生变量控制能力的实施和分析

设计受控实验是科学实验实证的重要手段,这种科学探究的核心能力,也是教育部在《普通高中化学课程标准(2017年版2020年修订)》中对学生能力的评价之一.在分析学生能力现状、教材内容后,经过教学实施,充分利用教材,帮助学生认识变量控制要素,达成能系统地综合应用变量控制解决实际问题的教学目标.     

古代丝织品及古建彩画蓝色染料的微量及无损分析

染料分析是研究织物颜色老化变色的基础,同时对于了解我国印染工艺的发展有非常重要的作用。通过薄层色谱和拉曼光谱方法,对六个唐代丝绸样品的蓝色染料和故宫建福宫建筑彩画的蓝色物进行了分析,并对两种方法在文物上的适用性进行了比较。结果表明这些呈色物质均为靛蓝,靛蓝不仅作为染料被古人使用,也被当作颜料用于彩绘壁画,使用范围非常广范。两种分析的方法各有利弊,拉曼光谱是无损分析,薄层色谱需要样品量少,但可获得更多的信息。     

BP+基态和激发态的势能曲线和光谱性质的研究

本文利用量子化学中的多参考组态相互作用方法(MRCI), 在aug-cc-pVQZ级别计算了在环境科学中具有重要作用的离子BP⁺. 得到了对应三个离解极限B⁺(¹S_g)+P(⁴S_u), B⁺(¹S_g)+P(²D_u)以及B⁺(¹S_g)+P(²P_u)的6个Λ-S态势能曲线. 在计算中还考虑了Davidson修正(+Q)和标量相对论效应, 用以提高计算精度. 通过分析Λ-S态的电子结构, 确认了电子态的多组态特性. 计算中首次纳入了旋轨耦合效应, 获得了由BP⁺离子的6个Λ-S态分裂出的10个Ω 态的势能曲线. 计算得到的势能曲线表明相同对称性的Ω 态的势能曲线存在着明显的避免交叉. 在得到的Λ-S态和Ω 态的势能曲线的基础上, 运用LEVEL8.0程序通过求解核径向的Schrödinger 方程, 得到了相应的Λ-S态和Ω 态的光谱常数T_e, R_e, ω_e, ω_eχ_e, B_e和D_e, 其中基态X⁴∑^-的光谱常数与已有的理论值符合的非常好, 文中其他电子态的光谱常数均为首次报道. 关键词： 多参考组态相互作用方法(MRCI) 势能曲线 光谱常数 旋轨耦合效应     

Organocatalytic enantioselective sulfa-Michael addition of thiocarboxylic acids to β-trifluoromethyl-α,β-unsaturated ketones for the construction of stereogenic carbon center bearing a sulfur atom and a trifluoromethyl group

An organocatalyzed asymmetric sulfa-Michael addition of thiocarboxylic acids to β-trifluoromethyl-α,β-unsaturated ketones with a chiral bifunctional amine-squaramide as the catalyst is presented. A wide range of chiral ketone compounds bearing a sulfur atom and a trifluoromethyl group at the stereogenic carbon center could be obtained with excellent results (up to 99% yield, 97% ee) under mild conditions. The developed catalytic system is well-tolerated to both (E)-and (Z)-β-trifluoromethylated-α,β-unsaturated ketones.     

海底爆破辐射声场的理论及数值研究

对固体基底浅海中声波传播的色散特性作了数值模拟与分析. 利用液体及固体中声传播理论导出了固体基底内爆破源在浅海中所激发声场的解析解, 在此基础上, 通过数值计算, 得出了浅海中不同空间点处的瞬态声压时域波形, 并在瞬态声压时域波形的平滑伪Wigner-Ville分布基础上, 对固体基底内爆破源在浅海中所激发瞬态声场的特性作了详细分析. 关键词： 海底爆破 声场 色散 瞬态声压     

新型表面活性剂的合成与表征综合实验设计

将专业综合实验与科研成果相结合,设计了新型表面活性剂的合成与表征综合化学实验。实验涉及含羟基基团的表面活性剂的合成、纯化、结构表征和性能测定等操作。该综合实验将有机化学基础知识、表面活性剂的基本性质与前沿科学研究相结合,从而实现学生实验技能的提升、认知视野的拓展和综合能力培养的目标。