Immunochemical characterisation of structure and allergenicity of peanut 2S albumins using different formats of immunoassays

Proteins of the 2S albumin family, such as Ara h2 and Ara h6, are most frequently involved in peanut allergy. We have developed a reverse enzyme allergo-sorbent test (EAST) in which total serum IgE antibodies are first captured by immobilised anti-human IgE monoclonal antibodies, and then the binding of the anti-Ara h2 and anti-Ara h6 specific IgE to the corresponding labelled allergens is measured. This reverse immunoassay was used either as a direct EAST or as an EAST inhibition assay to study the interactions of whole peanut protein extract and purified Ara h2 and Ara h6 with IgE antibodies from peanut-allergic patients. Finally, we identified some IgE-binding epitopes on Ara h6 using a format of EAST in which the protein is immobilised in a particular, well defined, manner through interactions with specific monoclonal antibodies (mAbs) coated on the micro-plates. The fine specificity of those mAbs has been characterised at the epitope level, and their binding to the allergen thus masks a known particular epitope and makes it unavailable for recognition by IgE antibodies. The reverse EAST increased the ratio specific signal/background. It avoids interferences with competitors such as anti-peanut protein IgG antibodies and allows the study of the specificity and/or affinity of the interactions between IgE antibodies and Ara h2 or Ara h6 with a higher sensitivity and accuracy than the conventional EAST. The EAST results obtained when the allergens are presented by specific mAbs suggest that the homologous molecular domain(s) in peanut 2S albumins encompass major IgE epitope(s) and are strongly involved in peanut allergenicity.     

Laser-induced breakdown spectroscopic characterization of impurity deposition on the first wall of a magnetic confined fusion device: Experimental Advanced Superconducting Tokamak

Our recent investigations have indicated the potential of laser-induced breakdown spectroscopy (LIBS) for analysis of the co-deposited layers on the first wall in the Experimental Advanced Superconducting Tokamak (EAST) in the vacuum environment. Detailed information of compositions at the superficial and in-depth positions of the first wall of divertor tiles can be obtained by analyzing the spectra from 200 to 980 nm. The decrease in concentrations of the depositional elements (such as D, Li) was clearly observed in the depth from 0 to 100 μm, but the concentrations of the substrate elements were found to be relatively uniform in the depth after dozens of laser pulses. The linear correlation approach has been applied for improving the impurity depth profile accuracy and identifying the interface boundary between the deposition layer and the substrate for the first time. This would help us to develop LIBS technique to monitor the fuel retention and impurity deposition on the first wall of EAST.     

Polyolefins: The most promising large-volume materials for the 21st century

Polyolefins (POs) constitute an extremely interesting family of materials. They include large-volume materials such as polyethylene and polypropylene and specialty materials. Outstanding scientific and technology developments have led to the most aggressive, endless, always increasing, successful growth speed of any family of large-volume materials. For those of us who have lived through the entire PO adventure, from its problematic beginnings to the eventual successful developments of the last 25 years, it has been a quite unforeseeable and unexpected story not shared by the majority. The main reason for such behavior and the present situation is the inherent complexity of their catalytic systems, which are difficult to understand and manage, along with all the consequences in terms of the process versatility, the reliability and cost, the lack of product properties, and the possibility of new material creation and commercial availability. After the early commercial disappointments of the 1960s and early 1970s, the deep commitment of the industry in research and development, mostly aimed at an understanding of the catalysis and its improvement and management, created the basis for and led to the generation of new, elegant, and versatile processes and, most importantly, to the generation of new products and properties. It activated that dynamic and aggressive growth that, since the late 1970s, has characterized the entire PO market and still, at the beginning of the third millennium, is not showing any sign of decline. An attempt to provide a rational explanation for such a unique case of technological and commercial success in the history of materials has led us to the following conclusions. First, dramatic improvements in the polymer properties and the generation of new materials have been the key reasons for their commercial success and continuous market expansion. Second, the tremendous and dynamic development of new, elegant, and versatile technologies has been and is the fundamental prerequisite for the generation of that rich world of new properties and materials. Third, the strategic management of the technological background and potential for the creation of new properties and new applications has been and is the basis for the fast and successful market expansion. The key technological driving force has been the understanding and management of the catalytic system. The early generations of chromium-based and Ziegler–Natta catalysts, after a difficult beginning, have progressively accelerated in their development toward new revolutionary generations with outstanding potential in terms of the creation of new polymer properties. The most recent families of single-site catalysts, together with the still largely unexploited potential of the previous Ziegler–Natta, chromium, and vanadium catalysts, are showing the ability to guarantee the continued support and fueling of the expansion for several further decades. The development philosophy will always be more tuned toward the creation of low-cost, low-environmental-impact polymers and processes, with a minimum amount of constraints. Today, at the beginning of the new century, we see the PO future as still very bright because of the huge, unexploited potential of already existing and emerging technologies. The PO adventure continues and is still exciting like it was 50 years ago. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 396–415, 2004     

Study of complex mixtures of natural substances by the defocusing and dadi methods. VI. Components of the secretion of the pre-anal gland of some poisonous snakes

By mass-spectrometric methods, cholesterol and docosanoic, heneicosanoic, cicosanoic, octadecanoic, cis-octadec-9-enoic, heptadecanoic, hexadecanoic, and pentadecanoic acids have been identified in the odoriferous secretion of the pre-anal glands of the females and males of the common adder and the saw-scaled viper and in those of females of the common mamushi. It has been established that the chemical compositions of the secretions of these glands of the females of the adder, the viper, and the mamushi and of the males of the adder and of the viper are not identical.     

均聚物结晶与熔融化的稳态和亚稳态转变统计理论

基于多重微晶网络结构模型和分子分凝机制建立了高分子晶体的微晶核-和微晶粒-高分子链组模型,推导出了平衡态下高分子预结晶动力学方程,计算出了平衡态下不同尺寸微晶核-和微晶粒-高分子链组的几率分布函数.建立了非稳态下不同尺寸的微晶核-高分子链组的成核演化方程和微晶粒-高分子链组的增长演化方程,求解一般状态下的两个演化方程后,得到了不同时间和不同尺寸的微晶核-和微晶粒-高分子链组的一般密度分布函数.最后根据成核自由能和增长自由能对晶核和晶粒的尺寸大小的依赖性,提出了微晶核-高分子链组和微晶粒-高分子链组存在稳定性的热力学条件和动力学条件,成功地表征为三个特征区(稳态、亚稳态和非稳态).     

OPTICAL ROTATION STUDIES OF COPPER (II)-TRIPEPTIDE COMPLEXES

Abstract

Copper(II) complexes of various optically active di- and tripeptides have been studied with the aid of optical rotatory dispersion (ORD) and circular dichroism (CD) techniques. The magnitudes of the molecular rotations related to the d-d transitions of the complexes fall into three different ranges, depending on the positions of asymmetric carbon atoms of the ligands. The molecular rotations of GAG and GLG complexes are greater than those of GGA, GGL, and GGV complexes, which are again greater than those of AGG, LGG, and VGG complexes (G, A, L, and V are glycine, alanine, leucine, and valine residues, respectively, in the tripeptides investigated, the N-terminal residue being the first residue in each abbreviation). The structures of these complexes, deduced from their potentiometric equilibrium curves and from the known crystal structure of the copper(II)-triglycine complex, show that the asymmetric carbon atoms of the second and third amino acid residues (counting from the N-terminal amino acid residue) are in the plane composed of the central metal ion, the nitrogen atoms of the amino and peptide groups, and the oxygen atom of the carboxylate group. The magnitude of the Cotton effect increases with the planarity of the chelate rings which include the asymmetric carbon atom and the metal ion, and with increasing strength of the coordinate bonds that form these chelate rings. Further support for this interpretation is found in the CD spectra of the copper(II) and nickel(II) complexes of AGG, GAG, GGA, and AAA. Analysis of the CD spectra of LL and DL alanylalanine complexes also demonstrate the influence of planarity and coordinate bond strength on the magnitude of the Cotton effect. Schiff base formation of aldehydes and ketones with dialanines causes fundamental changes in the geometries of the copper(II) complexes and reverses the relative contributions of the chelate rings to the total CD absorption intensities of the complexes.     

Comparison of biased and unbiased estimators of variances of qualitative and semi-quantitative results of testing

Unbiased estimators of within-laboratory and between-laboratory (or within reference material unit and between-unit) variances of results of qualitative and semi-quantitative testing are formulated and discussed. Qualitative and semi-quantitative test results were treated as binary nominal and ordinal values, respectively, in framework of the newly developed ordinal analysis of variance (ORDANOVA). It is shown that the difference of the unbiased and the biased estimators of a within-laboratory variance does not exceed 5 %, when the number of replicate tests in a laboratory is larger than 20. Such a difference is increasing when the replicate number is decreasing, not depending on the number of laboratories and the between-laboratory variation, since both the unbiased and the biased estimators are based on the averaged within-laboratory variances. The difference of the unbiased and the biased estimators of the between-laboratory variance depends not only on the number of replicates, but also on the number of laboratories and on the ratio of the contributions to the total variance (the between-laboratory variance and the averaged within-laboratory variance). This difference does not exceed 5 %, when the number of replicates and the number of laboratories are larger than 20 and the ratio of the between-laboratory to the averaged within-laboratory variances does not yield 1. For a limited size of experiment (smaller numbers of replicates and laboratories), the difference is increasing with the size decreasing and can be significant.     

Dihydrofolate reductase: structural aspects of mechanisms of enzyme catalysis and inhibition

The mechanism of catalytic reduction of folic and dihydrofolic acids to tetrahydrofolate, which proceeds under the action of dihydrofolate reductase and the coenzyme NADPH, is considered. The roles of the enzyme active site, the coenzyme, individual amino acid residues of the enzyme, and water molecules in the catalytic reaction are discussed. Interactions of the enzyme with competitive inhibitors many of which are widely used in medicine as antitumor and antibacterial drugs are examined. The factors controlling the selectivity of inhibitor binding to bacterial forms of the enzyme are analyzed. The results of X-ray diffraction and NMR spectroscopic studies of the structures of the enzyme and its complexes with the substrate and inhibitors are surveyed. The role of specific interactions and molecular motions of the protein and ligands in the mechanism of catalysis and in the binding of the ligands to the enzyme is discussed.     

Statistical Theory of Stable and Metastable Transition for Crystallization and Fusion of Homopolymers III Statistical Dynamics of Polymeric Crystallization by Molecular Segregation A General Characteristics for Growth-Rate of Melt-grown Crystals and Their

At first a comprehensive and short review on the characteristics for size growth-rate of crystals is presented. Based on the structural model of micro-nucleus- and crystal-constituent chains and the feature of grown mechanism for crystallization by the molecular segregation of stems, a general principle and method for characteristics of the number growth-rate for micro-crystal-constituent chains and the size growth-rate for crystals by melt-crystallization was proposed. According to the principle, a set of quantitative expressions for the number growth-rate of constituent chains with different sizes and different lengths of segments and the size growth-rate of crystals by four different types of growth with folding, extending, parallel combination of folding and extending and series combination of folding and extending chains was derived by the combination method of statistical mechanics and kinetics. Then four growth-rate equations for the number of constituent chains and the size of crystals produced by four different types of growth are also obtained. These equations can be successful in relating the growth-rate-to the different types of growth and temperature of crystallization and supper-cooling.     

准确快速计算含多肽酰胺和核酸碱基的氢键复合物的氢键强度和氢键作用势能曲线

N-H···O=C、C-H···O=C、N-H···N和C-H···N等氢键作用是蛋白质a-螺旋结构、b-折叠结构和DNA双螺旋结构形成的主要因素,在生物分子识别、蛋白质复制以及遗传信息传递等过程中起重要作用。准确快速计算生物体系中存在的N-H···O=C、C-H···O=C、N-H···N和C-H···N等氢键作用强度以及氢键强度随分子几何结构(距离和角度)变化的势能曲线对正确模拟(从而正确认识和理解)蛋白质折叠机制和DNA双螺旋结构形成机制等生物过程意义重大,对设计合成具有特殊功能的生物分子材料有重要指导价值。本文主要介绍了近年来建立的偶极-偶极氢键作用模型及其在快速预测多肽-多肽分子间和核酸碱基-多肽分子间氢键作用强度和氢键作用势能曲线方面的应用。     

Liquid-phase oxidation of dibenzyl ether by atmospheric oxygen in the presence of homo- and heteroligand pivalate and 3,5-dimethylpyrazolate complexes of 3<Emphasis Type="Italic">d</Emphasis> metals

The main products of the reaction in the presence of homo- and heteroligand pivalate and 3,5-dimethylpyrazolate mono-, bi-, and trinuclear complexes of Co, Cu, Ni, and Zn are the hydroperoxide, benzaldehyde, and benzoic acid. The effect of the composition and structure of the complexes on the conversion of the substrate, the selectivity of the process, and the possibility of alternative routes to the oxidation of dibenzyl ether is discussed.     

Thermal effects accompanying stationary binary condensation of vapors into overcritical droplet

A set of equations is derived to calculate the stationary temperature and concentration of a solution in a overcritical droplet with regard to the heat release accompanying the condensation of a binary mixture of vapors in a diffusion or free-molecular regime. In the approximation of an ideal solution, relations are found for the stationary temperature of droplet growing under the conditions of strong and weak thermal effects. For the general case and the cases of strong and weak thermal effects, the temperature and concentration of the droplet and the coefficient of the thermal deceleration of the droplet growth are calculated as functions of the density of a passive gas. The influence of the condensation heat values of the first and second components of the mixture on the stationary temperature and concentration of the solution in the growing droplet is investigated separately.     

Effect of counter- and co-ions on the structural transport parameters of sulfoacid cationite membranes

The diffusion permeability and specific electroconductivity of MK-40 sulfoacid cationite and Nafion 425 membranes are studied experimentally in NaOH, NaCl, and HCl solutions with various concentrations. The resulting concentration dependences of the electrodiffusion characteristics and data on the nonexchange sorption of the electrolytes are used to calculate the structural transport parameters of the membranes in terms of a two-phase conduction model. Analysis of a set of parameters, including the electroconductivity and diffusion permeability of the membrane gel phase, the volume fractions of the conductive phases, and a parameter that reflects their relative positions, the Donnan constant, and the diffusion coefficients of counter and co-ions in the membrane gel phase reveals the effect the nature of counter- and co-ions has on the electrodiffusion, structural, and sorption characteristics of sulfoacid cationite membranes with different types of structure.     

裂解气相色谱-质谱分析火场残留物中助燃剂

通过对火灾现场助燃剂及其燃烧残留物进行分析，开展了基于裂解气相色谱-质谱法（PyGC-MS）的火场助燃剂分析方法。选取了汽油和柴油2种助燃剂以及棉布和聚对苯二甲酸乙二醇酯（PET）塑料2类载体，制备了助燃剂与载体的混合燃烧残留物。利用热分析技术确定样品的特征性温度，并对分析条件进行优化与选择。通过闪蒸分析和裂解分析的分步裂解方法，对样品进行了PyGC-MS分析。实验结果表明，PET载体原样燃烧残留物的裂解产物共有35个组分，而PET载体与汽油混合燃烧残留物和PET载体与柴油混合燃烧残留物的裂解产物只有25个组分，且各裂解产物的种类和含量均不相同。该法可对同一载体的自身燃烧残留物和与助燃剂混合燃烧残留物进行区分，适用于火灾残留物中助燃剂的分析，可对火场中是否存在助燃剂进行判别，为火灾性质的判断和火灾调查工作提供科学依据。     

Effect of anharmonicity and vibrations resonance interaction in the vibrational spectra of H-bonded crystals

On the basis of the absorption coefficient calculation it is shown that strong optical and mechanical anharmonicity of the OH group vibrations and the interaction between the main tone and the overtone of the other vibration of the same OH group and the same symmetry (Fermi-resonance) leads to the formation of two-phonon bound states (biphonons) seen in spectra as “additional” sharp bands. The IR and Raman bands half-width and shape of the main tone and the bound state is measured as a function of temperature and a possible theoretical treatment is proposed. The anharmonicity parameters and low-frequency vibrations responsible for the temperature behavour of the main tone and the biphonons are determined.     

高效液相色谱法分离蛋白质的大孔硅质固定相的制备及分离机理

介绍了不同孔径的大孔硅胶基质的制备，二醇基和氨基固定相的合成，及其蛋白质的分离特性。探讨了流动相中的盐浓度和pH对蛋白质保留时间的影响，以及在此两种固定相上蛋白质分离机理的比较。由于大孔填料具有小的比表面积、往容量也低，从而有利于作蛋白质等生物大分子的高效快速分离分析。     

高密度互连印制电路板孔金属化研究和进展

孔金属化互连是印制电路板（PCB）高密度集成的核心制程之一,化学镀铜和电子电镀铜是实现孔金属化的关键技术。本文介绍HDI-PCB的概念和制作流程;综述化学镀铜和电子电镀铜孔金属化互连的研究和进展,包括溶液组成和操作条件的影响,添加剂及其相互作用机理,以及盲孔填充和通孔孔壁加厚机制;展望高密度互连印制电路板电子电镀基础研究及新技术发展方向。     

Transformations of organic compounds in supercritical fluid solvents: From experiments to kinetics,thermodynamics, simulation,and practical applications

The results of fundamental studies performed by the author on the reactivity of supercritical fluid solvents are systematized and generalized; practical applications of these solvents are considered. Methods for performing kinetic and physicochemical experiments, processing the data, constructing kinetic models, and calculating the thermodynamics of nonideal supercritical fluids (the parameters of critical points, binodal and spinodal lines, and critical point drifts; the thermophysical properties of reaction mixtures under supercritical conditions; etc.) are described. Attention is focused on the effect of supercritical fluid pressure on the rate constants of chemical reactions. The kinetics and mechanisms of the reactions of 2-propanol dehydration and decomposition of aliphatic nitro compounds in supercritical water and the isomerization of terpene compounds (α-pinene, β-pinene, and turpentine) in supercritical lower alcohols are studied. The formation of nanoparticles in supercritical fluid solvents and the treatment of ultradisperse diamonds in supercritical water are considered. The results formed the basis for the simulation and calculation of acetic acid and phenol oxidation processes in supercritical water and the Fischer-Tropsch synthesis in a supercritical solvent and for the development of a pilot plant for the complete oxidation of trinitroglycerol and diethylene glycol dinitrate in supercritical water.     

Some problems in adsorption and calorimetric studies of the steps of catalytic processes

Principal side factors as well as technical and procedural peculiarities capable of distorting the results of measurements of adsorbed and desorbed amounts, of falsifying the nature of the processes proceeding in the systems under study, and of promoting artifacts in calorimetric and other studies of gas chemisorption on powders are considered. Modified techniques and procedures allowing the elimination of sources of side phenomena and artifacts and freeing traditional glass static adsorption apparatuses and experimental procedures from undesirable factors and peculiarities are proposed. Some available chemisorption and calorimetric data representing artifacts and also some data that are not artifacts but,due to imperfections of chemisorption techniques, show up as artifacts are presented and discussed. Several applications of the improved techniques and procedures to calorimetric and adsorption studies of the steps of catalytic processes proceeding on the basis of natural gas and of products of its processing are presented and discussed.     

Evaluation of effect of functionalized gold nanoparticles with a partial negative charge on stability of DNA molecule: a study of molecular dynamics simulation

Today, understanding the interaction between DNA molecule with nanoparticles and functionalized nanoparticles has a significant importance in medical applications and targeted drug delivery. Molecular dynamics simulation on double-stranded molecule with the structure of the double helix and sequence of (CCTCAGGCCTCC) was performed in three states. The aim was to evaluate the effect of gold nanoparticles (GNPs) with partial negative charge on the stability of a DNA molecule. During the simulation process, the GNPs become closed to the DNA molecule and phosphate groups of the DNA molecule guided the nanoparticles toward its major groove. At the end of the DNA molecule chain, the terminal nucleotide of the chain was laid flat on the surface of the GNPs due to excessive exposure to solvent molecules and occurrence of peeling and untwisting states. According to the results, proximity of the GNPs and functionalized GNPs to the DNA molecule led to increased configuration entropy. While conformational energy and van der Waals energy of the DNA molecule increased in the presence of the GNPs and functionalized GNPs, there was a reduction and an increase in the number of hydrogen bonds between complementary bases in the presence of the GNPs and functionalized GNPs, respectively. Radial distribution function was estimated for water molecules and sodium cations, compared to oxygen atoms of the phosphate group of the DNA molecule. Results were indicative of the release of water molecules from around the DNA molecule in the presence of the GNPs. In addition, the distance between sodium cations and the GNPs decreased. Nevertheless, no such phenomenon occurred in the presence of the functionalized GNPs. Therefore, according to results, it seems that GNPs decreased the stability of the DNA molecule and the functionalized GNPs with partial negative charge caused structural changes and created compression, but did not destroy the double-strand structure of the DNA molecule.