基因传感技术及目前存在的问题和发展对策

对最近几年报道的比较有特色的光学、压电、电化学等基因(DNA)传感器方面的研究工作进行介绍,并就目前基因传感器研究中存在的问题进行了分析讨论,提出了相应的发展对策.     

Electronic structure and conductance of large molecules and DNA

Using a new technique based on embedding in a local orbital formalism, the electronic structure and electron transmission properties of long biological molecules are calculated, in particular DNA. The electronic structure is found by adding one structural unit at a time to the molecule, and calculating an embedding potential for adding the next structural unit. At present, an extended Hückel scheme is used for the Hamiltonian. The transmission is also calculated within the embedding scheme, taking the molecule–metal contacts into account. The results for transmission depend greatly on the orbitals to which contact is made, and also on energy. The implications of these calculations for conductance are discussed.     

免疫分析与细胞检测新原理与新方法研究

将分析化学与临床诊断相结合,发展临床检测新原理、新方法已成为人类健康的前沿领域之一,其中免疫分析,特别是多标志物同时免疫检测新方法的发展,与细胞检测已成为人们关注的课题。本文综述了近3年来这方面的研究进展, 并简要介绍了免分离、准无试剂和全无试剂安培免疫分析,空间分辨多通道安培芯片,底物区带分辨、通道分辨和通道-底物区带二维分辨化学发光免疫分析等多种免疫分析新概念,细胞检测与表面增殖监测、细胞毒效应研究与药敏检测新方法,对其在肿瘤临床诊断中的应用也作了总结。     

Heat- and high-temperature-resistant adhesives for joining carbon and ceramic materials

A review of the literature datas on the application of adhesives based on inorganic binders for joining carbon and ceramic materials was presented and their advantages and disadvantages were revealed. It was concluded that the most preferable for many application fields are polymer carbonizing adhesives with special fillers, and the most promising are the cold-setting adhesives. Datas are presented on the development of new modified ZhTK-14D adhesive compositions that are efficient at temperatures up to 1800°C intended for joining carbon and ceramic materials.     

Rapid and simple determination of aldose reductase and sorbitol dehydrogenase

Rapid and well-reproducible methods were developed for the determination of aldose reductase and sorbitol dehydrogenase. The aldose reductase activity measurement is based on photometric o-toluidine aldose back-measurement, which is widely used in laboratories for the quantitative determination of glucose. The spectrophotometric method based on the quantitative decrease in NADH proved suitable for the measurement of sorbitol dehydrogenase activity.Both methods could well be employed for the measurement of the aldose reductase and sorbitol dehydrogenase activities of normal and diabetic tissue homogenizates, and for the comparison of the measured values.     

Adsorption of hydrocarbons from solutions and gas phase on silica and alumina modified with silver and gold ions

The paper reports the immobilization of Ag⁺ cations on alumina and silica and AuCl ₄ ^? anions on amino silica and alumina. The method of inverse gas chromatography have demonstrated that Ag(I)-silica is selective for the separation of alkanes, alkenes, alkines, and arenes. The dependence of the capacitance of Ag(I) and Au(III) composites with regard to phenylacetylene (PHA) on the nature of the carriers, surface concentration, and technique of immobilizing ion metals has been considered. The isotherms of the adsorption of PHA from solutions in octane have been measured. It has been revealed that the capacitance of composites with regard to toward PHA prepared by the immobilization of ammoniates of silver nitrate on silicon dioxide is several times higher than for composites based on alumina with the same silver concentration and composites prepared by the immobilization of silver nitrate on silicon dioxide. The capacitance of the Au(III) composite based on alumina for PHA is significantly higher than for that based on aluminum oxide. The highest capacitance for PHA (0.83 and 0.88 molecules per metal ion) is observed for Ag(I) silica and the Au(III) alumina composite. In the visible region, the diffuse reflection spectra of amino silica Au(III) composites have a significant shift of the maximum of adsorption band along with the decrease in the concentration of immobilized anions of AuCl ₄ ^? , which evinces the formation of coordination bonds between free amin?propyl groups of the silica carrier and gold atom. The formation of these bonds prevents the adsorption of PHA on amino silica Au(III) composites with low gold concentrations.     

面向资源和环境的石油化工技术创新与展望

当前,我国石油化工面临着资源和环境等方面的重大挑战,石油化工新技术创新对于促进我国石油化工可持续发展以及保障国家能源安全等意义重大.本文列举了近年来在反应工程、过程耦合与强化、新型催化材料创制以及集成创新等方面的创新实例,总结了包括技术创新途径、方法等方面的若干对创新过程的认识和体会.最后,在分析了石油化工技术未来发展趋势与需求的基础上,对我国石油化工发展方向与技术创新进行了展望,并提出了建议.     

Nanomaterials and nanotechnologies in chemical and biochemical sensors: Capabilities and applications

The publications reporting on the use of nanomaterials and nanotechnologies in chemical and biochemical sensor designing were reviewed for the recent decade. The capabilities and applications were discussed for nanoparticles based on gold, silver, magnetic and semiconductor materials (quantum dots), lanthanides, and silica compounds, as well as for nanotubes and nanolayers (Langmuir-Blodgett films, selfassembled monolayers) used in optical (absorbance, luminescence, surface enhanced Raman spectroscopy, surface plasmon resonance), electrochemical, and mass-sensitive sensors. It was shown that the unique capabilities of nanosensors might hold the key to improve the analysis of liquids, gases, and especially biochemical and biological objects in the near future.     

Electroanalytical biosensors and their potential for food pathogen and toxin detection

The detection and identification of foodborne pathogens continue to rely on conventional culturing techniques. These are very elaborate, time-consuming, and have to be completed in a microbiology laboratory and are therefore not suitable for on-site monitoring. The need for a more rapid, reliable, specific, and sensitive method of detecting a target analyte, at low cost, is the focus of a great deal of research. Biosensor technology has the potential to speed up the detection, increase specificity and sensitivity, enable high-throughput analysis, and to be used for monitoring of critical control points in food production. This article reviews food pathogen detection methods based on electrochemical biosensors, specifically amperometric, potentiometric, and impedimetric biosensors. The underlying principles and application of these biosensors are discussed with special emphasis on new biorecognition elements, nanomaterials, and lab on a chip technology.     

Integrated biosensors: Promises and problems

After a brief review of the biosensors area, this paper explores the possibilities of integrating various classes of biosensors on silicon. Of all classes of sensors, electrochemical and bioelectrochemical sensors are the most suitable for integration, although substantial research on the fabrication and understanding of bioactive layers on semiconductor sensors is still required. Optical, gravimetric and thermal sensors could also be integrated to varying extents; however, the cost benefits are not yet very attractive except for immunosensors based on immobilized immunoglobulins. Electrochemical and gravimetric sensors based on silicon show the greatest potential for batch fabrication and could therefore be best suited for disposable sensors. The review ends with a discussion of the technological, functional and conceptual problems associated with integrated biosensors.     

Identification and functional study of cytokines and chemokines involved in tumorigenesis

Tumorigenesis may be affected by various cellular components in the tumor cells and/or by tumor microenvironmental factors. Cytokines, including chemokines (chemotactic cytokines) are polypeptides or small soluble proteins generated by leukocytes and non-leukocytes, including cancer cells and stromal cells, for example, fibroblasts, mesenchymal stem cells (MSCs) and epithelial cells. Cytokines exert their functions on the cells that secrete them, on nearby cells, or on distant cells. Chemokines have expanded beyond their initial roles in impinging on every aspect of the immune system and leukocyte biology. They display multifunctional effects for regulating angiogenesis, tumor cell proliferation and apoptosis, mediating tumor cell metastasis in an organ-specific manner. This review will focus on the structural and functional aspects of chemokines as well as the roles that cytokines and their receptors play in angiogenesis, tumor invasion and metastasis, and discuss their potential value as important therapeutic targets for intervention in cancer.     

Frustration and hydrophobicity interplay in protein folding and protein evolution

A lattice model is used to study mutations and compacting effects on protein folding rates and folding temperature. In the context of protein evolution, we address the question regarding the best scenario for a polypeptide chain to fold: either a fast nonspecific collapse followed by a slow rearrangement to form the native structure or a specific collapse from the unfolded state with the simultaneous formation of the native state. This question is investigated for optimized sequences, whose native state has no frustrated contacts between monomers, and also for mutated sequences, whose native state has some degree of frustration. It is found that the best scenario for folding may depend on the amount of frustration of the native structure. The implication of this result on protein evolution is discussed.     

Viscoelasticity and Stokes-Einstein relation in repulsive and attractive colloidal glasses

We report a numerical investigation of the viscoelastic behavior in models for steric repulsive and short-ranged attractive colloidal suspensions, along different paths in the attraction strength vs packing fraction plane. More specifically, we study the behavior of the viscosity (and its frequency dependence) on approaching the repulsive glass, the attractive glass, and in the reentrant region where viscosity shows a nonmonotonic behavior on increasing attraction strength. On approaching the glass lines, the increase of the viscosity is consistent with a power-law divergence with the same exponent and critical packing fraction previously obtained for the divergence of the density fluctuations. Based on mode-coupling calculations, we associate the increase of the viscosity with specific contributions from different length scales. We also show that the results are independent of the microscopic dynamics by comparing Newtonian and Brownian simulations for the same model. Finally, we evaluate the Stokes-Einstein relation approaching both glass transitions, finding a clear breakdown which is particularly strong for the case of the attractive glass.     

Local and global quantitative structure-activity relationship modeling and prediction for the baseline toxicity

The predictive accuracy of the model is of the most concern for computational chemists in quantitative structure-activity relationship (QSAR) investigations. It is hypothesized that the model based on analogical chemicals will exhibit better predictive performance than that derived from diverse compounds. This paper develops a novel scheme called "clustering first, and then modeling" to build local QSAR models for the subsets resulted from clustering of the training set according to structural similarity. For validation and prediction, the validation set and test set were first classified into the corresponding subsets just as those of the training set, and then the prediction was performed by the relevant local model for each subset. This approach was validated on two independent data sets by local modeling and prediction of the baseline toxicity for the fathead minnow. In this process, hierarchical clustering was employed for cluster analysis, k-nearest neighbor for classification, and partial least squares for the model generation. The statistical results indicated that the predictive performances of the local models based on the subsets were much superior to those of the global model based on the whole training set, which was consistent with the hypothesis. This approach proposed here is promising for extension to QSAR modeling for various physicochemical properties, biological activities, and toxicities.     

N-band Hubbard models for copper oxides and isoelectronic systems. New models for organic and organometallic magnetic conductors and superconductors

The electronic structures of undoped and doped copper oxides and other related oxides are investigated on the basis of the N-band Hubbard models. The Hubbard Hamiltonians for clusters of transition metal oxides are exactly diagonalized by the full valence-bond (VB ) configuration interaction (CI) method in order to elucidate populations of doped holes, electronic excitation energies, etc. Possible mechanisms of the high-T_c superconductivity for oxide superconductors are discussed on the basis of the calculated results, together with available experiments. The analysis of correlation and spin correlation effects on doped copper oxides indicates theoretical possibilities of new models for organic and organometallic magnetic conductors and superconductors. Organic and organometallic analogs to copper oxides are therefore proposed on the basis of these results.     

Laboratory guidelines and standards in clinical and forensic toxicology

An overview is given of the existing standards and guidelines for analytical toxicology. Details about guidelines concerning forensic toxicology, clinical toxicology, point-of-care testing, and an area of overlap are provided. Guidelines and standards exist for forensic toxicological analysis in general and for specific situations, e.g., workplace drug testing and driving under the influence of drugs and alcohol. For workplace drug testing, detailed guidelines exist in the U.S.A., Australia, and Europe describing for example the methods used, their cut-off and the process of sample handling. Some governments describe the methods and quality requirements for blood alcohol testing for driving under the influence of alcohol in detail in their laws. In the area of clinical toxicology, guidelines not only focus on the analytical aspects of analysis but also on the timeliness of results. According to the US- and UK-based practice guidelines for the emergency department, the turn-around time should be 1 or 2 h, respectively, for a specific set of analytes. Guidelines are either being developed now or already available (e.g., workplace drug testing, breath alcohol analysis) for point-of-care testing in analytical toxicology. In the context of brain death and sexual assault cases, specific demands need to be imposed because of the unique aspects of drug analysis in these situations (variety of drugs used, low concentrations). Many guidelines and standards are available and it is up to every laboratory to choose the best ones depending on the area of activity and the legal and regulatory environment.Presented at the 10th Conference Quality in the Spotlight, March 2005, Antwerp, Belgium     

Monomer adsorption on terraces and nanotubes

We construct a nonsparse transfer matrix (T-matrix) for a lattice gas model of monomers adsorbed on planar and nanotube surfaces of arbitrary geometry. The model can accommodate any number of higher-order pairwise adsorbate-adsorbate interactions. The technique is sufficiently general for application to nonequivalent adsorption sites and coadsorption of two or more monomer species. The T-matrices for monomer adsorption on a finite width terrace and for monomer adsorption on a nanotube, both of the same lattice geometry, share a basic G-matrix. First, the G-matrix is diagrammatically and recursively constructed. Then, its elements are modified to provide the T-matrix elements for either the terrace or the nanotube. The T-matrices for several particular lattice geometries previously studied as special cases are easily recovered with the generalized technique presented here. This generalization also provides a vectorized algorithm for efficient use on multi-parallel processors and supercomputers.     

氮原子在Ni平坦和缺陷表面上的吸附和振动

 构造了氮－镍相互作用的5－参数Morse势，研究了氮原子在Ni（\r\n100），Ni（110）和Ni（111）平坦表面的吸附和振动，获得了氮原子\r\n在三个低指数表面的吸附位、吸附构型、结合能和本征振动等数据，计\r\n算结果与实验结果非常吻合．同时，与Ni（100）表面对比，系统研究\r\n了氮原子在Ni（510）台阶面的吸附和扩散．计算结果表明，氮原子在\r\n台阶下部形成最稳定的吸附态，台阶对下台面上扩散的氮原子形成捕获\r\n势，对上台面上扩散的氮原子形成反射势．     

乙炔、丙烯在多种分子筛上的吸附和脱附性质

在80℃下研究了ZSM5、13X、Y、MOR、5A、SAPO34等多种分子筛和常见载体上乙炔和丙烯的吸附和脱附性能。结果表明,乙炔和丙烯在SiO2、γ-Al2O3上不吸附,而与分子筛存在较强的相互作用。对于同类型的分子筛,两者的饱和吸附量均随分子筛硅铝比的增大而减小。在同一种分子筛上,以摩尔计的丙烯吸附量均明显高于乙炔。在80℃改性β分子筛上乙炔和丙烯饱和吸附量可分别达到0.11mmol/g和4.89mmol/g,该结果明显高于文献报道的结果。     

Plasmochemical Neutralization of Ozone-Destroying Chladones and Fluorine- and Chlorine-containing Wastes

A plasmochemical technique for neutralizing ozone-destroying chladones and fluorine- and chlorine-containing wastes is considered. Experimental results obtained on applying this technique to neutralization of some halogen-containing substances are presented, together with the information gained on using the technological scheme of the process in designing and constructing an industrial installation for neutralizing wastes of a plant manufacturing polytetrafluoroethylene.