一种疏水色谱填料的特性及应用的研究

 以交联壳聚糖为基质 ,正戊醛为配基 ,利用改进的方法制备了疏水作用色谱 (HIC)填料 ,并对该色谱填料的吸附行为和应用作了研究。结果表明 ,此类填料对蛋白质的吸附行为符合疏水相互作用理论 ,对α 淀粉酶的纯化活性回收率大于 80 %。     

Discriminating Among Co‐monomer Sequence Distributions in Random Copolymers Using Interaction Chromatography

Interaction chromatography has been employed to validate that adsorption of poly[styrene‐co‐(4‐bromostyrene)] (PBr_xS) random copolymers, where x denotes the mole fraction of 4‐bromostyrene (4–BrS) in PBr_xS in solution depends on the average number of adsorptive segments, the type of adsorbing substrate, and on the co‐monomer sequence distribution in PBr_xS.

     

Molecular Dynamics Simulation Study of ClF in Water: Halogen Bonding Interaction in Liquid

Does the halogen bonding interaction co-exist in liquid when it competes with the hydrogen bonding interaction? The classical molecular dynamics simulations for the solvation properties of ClF molecule in water are performed with the Lennard-Jones plus Coulomb electrostatic potential parameters that are optimized with ab initio interaction energy calculations for the pre-reactive H₂O…ClF complex. We find that the halogen bonding interactions occur between O and Cl atoms and have the comparable strength and population with respect to the hydrogen bonding interactions of Cl…H.     

基于分子模拟和光谱法分析漆酶与甲酚的相互作用

该文运用计算模拟与光谱法研究了甲酚与漆酶的相互作用。首先,计算模拟表明漆酶与3种甲酚同分异构体都能发生相互作用,分子对接研究结果表明漆酶与甲酚同分异构体能以氢键和疏水作用力相结合,且结合位点相似。通过分子动力学模拟比较漆酶结合甲酚前后残基的柔性差异,验证了分子对接结合位点的可靠性。其次,选取计算模拟中结果较好的间甲酚,利用光谱法探究间甲酚与漆酶的荧光猝灭机制及结合前后漆酶二级结构的变化。荧光猝灭实验证实漆酶与间甲酚间是形成非荧光复合物的静态猝灭,与分子对接结果一致。红外光谱研究结果表明,漆酶与间甲酚结合后二级结构发生变化,其内部的β-转角和β-反向平行结构向β-折叠、无规则卷曲和α-螺旋结构转化,这与分子动力学模拟结果相呼应。该研究为利用漆酶转化环境中甲酚污染物提供了理论基础与数据支持。     

Laboratory Experiments to Study Radiocaesium Interaction in Organic Soils

Abstract

The total concentration of a pollutant in a given environmental compartment is often used for risk assessment. However, the real impact of the pollutant also depends on its toxicity and mobility. In soils, pollutant mobility is strongly related to its interaction with the different sites. The mechanisms and dynamics of this interaction may be studied by adsorption and desorption approaches. Adsorption experiments based on the measurement of the pollutant solid-liquid distribution coefficient (K_D) determine the interaction capacity of the soil and identify the nature of the sites involved. Desorption experiments based on single, sequential or consecutive extractions show the reversibility of the adsorption process (soil fixation capacity) and how it might be affected by changes in field conditions. They also predict changes in reversibility over time. In this work, the study of radiocaesium interaction in organic soils is used to illustrate these statements. In this study, the combined use of adsorption and desorption experiments shows that, even in highly organic soils, the specific sites of clay materials may govern radiocaesium behaviour.     

疏水作用色谱介质的合成及色谱特性研究

利用国产大孔硅胶作基质合成了疏水填料。按照高效疏水作用色谱法,采用梯度洗脱方式分离了6种标准蛋白及唾液中α-淀粉酶和基因工程生产的γ-干扰素。柱子不可逆吸附小、被试验的α-淀粉酶和溶菌酶活性几乎定量被回收。应用合成的色谱填料研究了洗脱剂中盐浓度和温度对蛋白质保留行为的影响,论证了合成填料的色谱属性。     

基于随机行走的二维空间扩散模拟研究

分子的扩散行为是微观化学的重要研究领域. 影响扩散行为的因素很多,但是目前各个因素的具体影响效果还不明确. 作者基于随机行走理论建立了分子在二维空间的扩散模型,依据此模型自主开发了模拟软件以及数据分析系统,并利用该模拟软件系统研究了势垒尧横向速度等因素对扩散行为的影响,验证了该模型的可靠性,证明根据该模型可以得到和实验尧理论相吻合的结果. 该软件有望成为模拟微观化学扩散行为的潜在平台,如电化学以及膜过滤过程中的扩散.     

Structure and Dynamics of Confined Polymer Melts from Attractive Interaction to Repulsive Interaction Between Polymer and Smooth Wall

We studied the static and dynamic properties of unentangled polymer chains which have a variable strength of interaction with the confining smooth walls by means of the lattice Monte Carlo simulation based on the bond-fluctuation model, that is, investigated the wall-polymer interactions which systematically vary from attraction to repulsion. A critical value of attractive potential(ε_wc) is found to be -0.6k_BT, and only below it can the adsorption layer of monomers be formed near the wall. At the critical point of attraction ε_wc, attractive interaction counterba- lances the wall-polymer excluded volume effect, which minimizes the confinement effects on both chain dimension and mobility. Influences on both chain dimension and mobility increase with the increasing of either attraction or repulsion imposed by the walls. Despite of the nature and strength of the wall-polymer interaction, with the decrease of film thickness, configurations more parallelly aligned and flattened are adopted by confined chains, and a systematic trend of deceleration is found. Variations of chain dynamics with both film thickness and wall-polymer interaction can be well explained by the corresponding changes in the confinement of the nearest-neighboring particles that surround the chains. Besides, the thickness of the interfacial layer inside polymer films, where chains adopt a flattened “pancake” shape, is about two times the bulk radius of gyration and independent of the wall-polymer interaction.     

Comparative Study of Flow Characteristics Inside Plasma Torch with Different Nozzle Configurations

A numerical analysis of the influence of different nozzle configurations on the plasma flow characteristics inside D.C plasma torches is presented to provide an advanced nozzle design basis for plasma spraying torches. The assumption of steady-state, axis-symmetric, local thermodynamic equilibrium, and optically thin plasma is adopted in a two-dimensional modeling of plasma flow inside the plasma torch. The PHOENICS software is used for solving the governing equations, i.e. the conservation equations of mass, momentum, and energy along with the equations describing the K-epsilon model of turbulence. The calculated arc voltages are consistent with the experimental results when arc current, gas inflow rate, and working gas are the same as the experimental parameters. Temperature, axial velocity contours inside plasma torches, profiles along the torch axis and profiles at the outlet section are presented to show the plasma flow characteristics. Comparisons are made among those torches. The results show that torches with different anode nozzle configurations produce different characteristics of plasma flows, which suggest some important ideas for the advanced nozzle design for plasma spraying. In order to validate the model and to show its level of predictivity, a comparison of the model with experimental results encountered in the literature is presented in the last part.     

混合超临界流体的密度及分子间相互作用

在３０８．１５Ｋ、６－１２ＭＰａ范围内,测定了ＣＯ２及ＣＯ２－正戊烷、ＣＯ２－正庚烷二元混合流体的密度,并计算了溶质的偏摩尔体积．在此基础上,将偏摩尔体积与ＭｏｎｔｅＣａｒｌｏ分子模拟研究相结合,研究了ＣＯ２－正戊烷、ＣＯ２－正庚烷二元系中的分子间相互作用和溶液的结构随压力和密度的变化．     

DCN1-UBE2M相互作用抑制剂的3D-QSAR、分子对接和分子动力学研究

类泛素化是一种蛋白质翻译后修饰,其异常会导致神经退行性疾病和多种肿瘤的发生,因此它被视为有希望的抗肿瘤靶标.研究表明,抑制DCN1-UBE2M相互作用可选择性阻遏类泛素化.本文基于哌啶基脲类DCN1-UBE2M相互作用抑制剂进行3D-QSAR、分子对接和分子动力学模拟研究.利用3D-QSAR中的CoMFA和CoMSIA...     

纺丝组件砂腔中流体流动性的冷态模型研究

自制冷态模型实验装置,针对熔融纺丝组件中的流体流动特征进行研究。实验结果表明:利用葡萄糖浆溶液作为PA6熔体的模拟介质是可行的,糖浆粘度与PA6熔体粘度有相似的变化规律及一定条件下粘度值相近,糖浆粘度随着剪切速率的增加而出现剪切变稀现象;在温度为21℃时,糖浆粘度与265℃时PA6熔体粘度接近,表明常温下,用糖浆作为模拟介质是可行性的;通过模拟介质在透明纺丝组件中流动特性的研究表明:流体在纺丝组件的砂腔中流动并不是理想的平推流,在压盖下方物料停留时间较四周长,不利于物料性质的均匀性。此研究实验结果为优化纺丝组件奠定了一定的基础。     

ZnO Nanoparticles Obtained by Green Synthesis as an Alternative to Improve the Germination Characteristics of L. esculentum

Tomato is an important crop due to its nutritional contributions and organoleptic properties, which make it an appetizing vegetable around the world. In its sowing, the use of seed is the most accessible propagation mechanism for farmers. However, the induction to germination and emergence is often limited in the absence of stimulants that promote the development and growth of the seedling, added to the interference of infectious agents that notoriously reduce the vitality and viability of the seed. Given this, it was proposed as a research objective to determine the effect of zinc oxide nanoparticles (ZnO NPs) mediated by a green route on the germinative characteristics of Lycopersicon esculentum Mill. 1768 “tomato”. The experimental phase consisted of the synthesis of ZnO NPs and its subsequent characterization. After its synthesis, its inoculation was conducted during the germination of seeds of L. esculentum, considering six sample groups for the treatment with zinc nanoparticles (T1: Control; T2: 21.31 ppm; T3: 33.58 ppm; T4: 49.15 ppm; T5: 63.59 and T6: 99.076 ppm). The results indicate that concentrations close to 100 ppm of ZnO NPs are ideal in the treatment of L. esculentum seeds, due to the promotion of enzymatic and metabolic activity to achieve cell elongation; likewise, the biosynthesized nanoparticles showed no phytotoxicity, due to the fact that, in all the treatments, there were processes of germination and emergence. This was linked to the generation of a Zn⁰-phenolate complex through a chelating effect, which generates compatibility with the seed and, compared to classic inorganic synthesis, usually shows phytotoxicity. In this sense, green synthesis is presented as a great alternative in this type of application.     

A Liquid Chromatography-Mass Spectrometry Method to Study the Interaction between Membrane Proteins and Low-Molecular-Weight Compound Mixtures

Molecular interaction analysis is an essential technique for the study of biomolecular functions and the development of new drugs. Most current methods generally require manipulation to immobilize or label molecules, and require advance identification of at least one of the two molecules in the reaction. In this study, we succeeded in detecting the interaction of low-molecular-weight (LMW) compounds with a membrane protein mixture derived from cultured cells expressing target membrane proteins by using the size exclusion chromatography-mass spectrometry (SEC-MS) method under the condition of 0.001% lauryl maltose neopentyl glycol as detergent and atmospheric pressure chemical ionization. This method allowed us to analyze the interaction of a mixture of medicinal herbal ingredients with a mixture of membrane proteins to identify the two interacting ingredients. As it does not require specialized equipment (e.g., a two-dimensional liquid chromatography system), this SEC-MS method enables the analysis of interactions between LMW compounds and relatively high-expressed membrane proteins without immobilization or derivatization of the molecules.     

A Simple UPLC/MS-MS Method for Simultaneous Determination of Lenvatinib and Telmisartan in Rat Plasma,and Its Application to Pharmacokinetic Drug-Drug Interaction Study

Lenvatinib is a multi-targeted tyrosine kinase inhibitor that inhibits tumor angiogenesis, but hypertension is the most common adverse reaction. Telmisartan is an angiotensin receptor blocker used to treat hypertension. In this study, a simple ultra-performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of lenvatinib and telmisartan, and it was applied to the pharmacokinetic drug interaction study. Plasma samples were treated with acetonitrile to precipitate protein. Water (containing 5 mM of ammonium acetate and 0.1% formic acid) and acetonitrile (0.1% formic acid) were used as the mobile phases to separate the analytes with gradient elution using a column XSelect HSS T3 (2.1 mm × 100 mm, 2.5 μm). Multiple reaction monitoring in the positive ion mode was used for quantification. The method was validated and the precision, accuracy, matrix effect, recovery, and stability of this method were reasonable. The determination of analytes was not interfered with by other substances in the blank plasma, and the calibration curves of lenvatinib and telmisartan were linear within the range of 0.2–1000 ng/mL and 0.1–500 ng/mL, respectively. The results indicate that lenvatinib decreased the systemic exposure of telmisartan. Potential drug interactions were observed between lenvatinib and telmisartan.     

Study of the impact of penetrant characteristics upon diffusion into Teflon membranes to further assess the performance of an ATR/FTIR sensor

In order to critically assess the performance and measuring dynamics of an attenuated total reflectance (ATR)/Fourier transform infrared (FTIR) sensor based on polymer preconcentration the impact of penetrant properties upon diffusion into the enrichment membrane must be characterised. Teflon AF2400, a highly amorphous and robust polymer not previously used in this role, was chosen as the enrichment membrane and various environmentally significant chlorinated hydrocarbon and alcohol species selected as analytes. Analyses were performed on aqueous solutions running in continuous flow configuration. Diffusion coefficients, calculated through regression of experimental data with simulated Fickian diffusion curves, were employed as the primary indicator of diffusion behaviour. Penetrant size and shape were both demonstrated to exhibit a substantial impact upon diffusion behaviour. Significant multi-component effects were observed for the simultaneous detection of two analytes. The results presented highlight the necessity for full characterisation of the observed effects prior to the development of a sensing technology for real applications.