A novel approach to chemical microarray using ketone-modified macromolecular scaffolds: Application in micro cell-adhesion assay

This paper describes a novel strategy for the preparation of chemical microarrays using macro-molecular scaffolds. The macromolecular scaffolds are first functionalized with ketone groups and compounds of interest containing an aminooxy group are conjugated onto the ketone-modified scaffolds through a chemoselective oxime ligation. The conjugate mixtures are then spotted directly onto a plastic or glass surface to form compound microarrays. Because a constant amount of scaffold is used in the presence of excess compound in the ligation reaction, the amount of compound actually immobilized per microarray spot is constant and dependent on the scaffold concentration. Using this approach, 60 different peptides were ligated to human serum albumin or agarose scaffolds, and the peptide conjugates subsequently printed on glass or polystyrene surface to form microarrays. These peptide microarrays were subsequently evaluated and optimized for binding of Jurkat leukemic cancer cells.     

Profiling of generic anti-phosphopeptide antibodies and kinases with peptide microarrays using radioactive and fluorescence-based assays

Kinases represent one of the largest enzyme families and key regulatory proteins in the cell. Only a small subset of these enzymes has been characterised so far. We have prepared different types of phosphopeptide and peptide microarrays displaying peptides deduced from annotated human phosphorylation sites and cytoplasmic domains of all annotated human membrane proteins. This approach was enabled by fully-automated high throughput micro-scale synthesis of peptides by the SPOT technology combined with chemo-selective immobilisation on modified glass slides. The phosphopeptide microarrays displaying 2923 peptides in total have been used for the characterisation of commercially available generic anti-phosphopeptide antibodies. This enabled us to detect Abl kinase activity on a microarray with anti-phosphotyrosine antibodies yielding results comparable to those obtained from a radioactive assay. More than 13 000 peptides deposited on six glass slides were used to profile casein kinase 2 (CK2) using a radioactive assay, since no generic antibody for the reliable detection of serine or threonine phosphorylation could be identified. All previously identified substrates were detected in the microarray experiment. In order to confirm whether substrates on the microarray are substrates in solution phase assays, more than 700 peptides were synthesised and tested with CK2 in a solution phase assay. All substrates identified in the solution phase assay were also detected on the microarray.     

高温超导本征结的制备工艺和特性

自从本征Josephson效应发现以来,由于其涉及到高温超导材料和结构、Josephson结动力学、高频应用等多个领域,本征结的研究一直是国际上研究的热点之一.我们采用低能离子刻蚀,实现了每分钟和单结本征结厚度相当的刻蚀速率,由BSCCO单晶成功的实现了含有单个或少数几个结的本征Josephson结的制备,并用四端子方法测量其低温下的I-V,Ic-T特性.通过反复实验研究,提高本征结制备的成功率及可重复性,完善制备工艺,并进一步探讨本征结的特性.     

An analysis of quantum coherent solar photovoltaic cells

A new hypothesis (Scully et al., Proc. Natl. Acad. Sci. USA 108 (2011) 15097) suggests that it is possible to break the statistical physics-based detailed balance-limiting power conversion efficiency and increase the power output of a solar photovoltaic cell by using “noise-induced quantum coherence” to increase the current. The fundamental errors of this hypothesis are explained here. As part of this analysis, we show that the maximum photogenerated current density for a practical solar cell is a function of the incident spectrum, sunlight concentration factor, and solar cell energy bandgap and thus the presence of quantum coherence is irrelevant as it is unable to lead to increased current output from a solar cell.     

PARTICLE DENSITIES AT THE CENTER REGION IN HIGH ENERGY HEAVY-ION COLLISIONS

Based on the two-chain model by A.Capella et al. the rapidity distributions of the multiplicity in high energy heavy-ion collisions, especially in head-on collisions, are discussed. The energy density at the center region in head-on collisions is estimated for different incident energies and different heavy ions. It is shown that the condition of the phase transition to the quark-gluon plasma can be realized in heavy-ion collisions at several tens of GeV.     

多孔聚四氟乙烯/氟代乙烯丙烯共聚物复合驻极体材料的压电效应研究

采用高温熔融和电晕充电方法制备了由聚四氟乙烯/氟代乙烯丙烯共聚物复合而成的空间电荷驻极体压电膜.借助准静态压电系数测量，研究了制备工艺对复合膜压电活性的影响.根据Kacprzyk等提出的复合驻极体膜的压电模型，结合等温表面电位衰减和压电系数衰减测量结果，讨论了驻极体复合膜系统中的压电性产生机制.结果表明，压电效应的大小不仅取决于俘获在材料中的电荷密度的大小，还与被俘获电荷在材料中的存在形式和分布有关. 关键词： 空间电荷驻极体 压电效应 聚合物复合膜     

Photorefractive hologram writing with high modulation depth in photovoltaic media under different boundary conditions

Photorefractive recording response to sinusoidal intensity pattern in photovoltaic media under different boundary conditions, namely, open-circuit, crystal-resistor-circuit, short-circuit and crystal-voltage supply-circuit, are investigated by solving steady-state Kukhtarev equations numerically. In high modulation depth m limit and when photovoltaic field becomes sufficiently large, we find that both the magnitude and imaginary part of fundamental space-charge field E₁ as a function of m may transit from superlinear increment to sublinear increment for short-circuit condition. The role of photovoltaic field in holographic storage and two-wave mixing is also discussed in comparison with an earlier experimental literature [G. Cook et al., Opt. Commun. 192 (2001) 393]. We further generalize Gu et al.’s remark on photovoltaic field and dc space-charge field, which is for small m only [C. Gu et al., J. Appl. Phys. 69 (1991) 1167], to whole range of m in the limit donor density much larger than ionized donor density that the effect of photovoltaic field cannot be cancelled or considered as an externally applied field for an arbitrary non-zero m.     

正向高密度脉冲电流激发下ZnSe MIS二极管中的自由激子发光

本文测量了在77K和正向脉冲电流密度为50～500mA/mm2的激发下,ZnSe MIS二极管的电致发光光谱.首次在高电流密度激发下的ZnSe晶体的电致发光光谱上,观测到自由激子与自由激子间(Ex-Ex)的散射.本中根据自由激子的动能分布,讨论了2LO声子协助的自由激子伴线的形状,发现当激发电流密度增高时,自由激子的有效温度大于晶格温度,这可归结为激子与激子间的非弹性散射.     

Profiling the immune responses of human patients treated with recombinant streptokinase after myocardial infarct

The SPOT synthesis of peptide arrays on continuous cellulose membranes should be generally applicable in the analysis of sequential antibody binding sites using the enzyme-substrate or other standard detection protocols. The use of total serum is limited by the occurrence of high background levels. This may be overcome if affinity purified antibodies or sera with high antibody titers are used, which allows work at high dilutions and a consequent reduction of background level. Here we demonstrate the mapping of antigenic regions located on recombinant streptokinase SK-2 (Heberkinase) using cellulose-bound peptide scans and human total sera from patients treated with SK-2 (Heberkinase). Streptokinase (SK) is a 47 kDa protein produced by various strains of hemolytic streptococci and is a potent activator of the fibrinolytic enzyme system in humans. SK is in widespread clinical use to treat acute infarction because of its function as an activator of vascular fibrinolysis. Since streptococcal infections are common, normal individuals are immunized with SK and antibodies (Abs) to SK can be detected in most of them. This therapy generates significant T-cell responses to SK and the neutralizing capacity of the Abs rises significantly. Neutralizing Abs reduces the efficiency of thrombolytic therapy and may cause allergic reactions. The widespread use of SK in humans makes its antigenicity an important clinical problem. In this regard the study of the immunodominant regions of SK becomes an important aspect for the improvement of this thrombolytic agent.     

硅基光栅耦合器的研究进展

硅基光子集成芯片的研究近年来发展迅速, 已成为信息技术领域中最热门的研究方向之一, 光通信、光互连、光传感等相关研发应用机构高度关注其发展, 并积极介入. 硅基光子集成芯片中, 光栅耦合器作为光信号的输入和输出装置受到极大重视, 尤其在封装和测试等环节体现出极具价值的技术优势. 本文主要分析了光栅耦合器的工作原理、基本特性及国内外的发展现状和趋势, 同时也概括了本课题组近期在该方向上的研究成果. 关键词： 光栅耦合器 耦合效率 绝缘体上硅 光子集成     

New planar substrates for the in situ synthesis of peptide arrays

The performance of new cellulose membranes, aminofunctionalized via a PEG spacer, as a solid support in the synthesis of peptide arrays is described. The new membranes are stable to trifluoroacetic acid (TFA) and strong aqueous base for days. These properties extend the scope of synthesis considerably, e.g., more efficient side chain cleavage protocols can be applied which yielded peptides of improved purity. For the first time, cellulose membranes with a loading as high as 5 micromol/cm2 were accessible. Additionally, newly developed polypropylene membranes with hydroxy- or amino functionalities were successfully employed for the SPOT synthesis of peptides and phosphopeptides. The membranes are compatible with antibody binding as well as enzymatic phosphorylation assays.     

Electron spin polarization in field emission

The field emission microscope can be extended to determine the directionally weighted spin-dependent surface density of states of magnetic metals or to obtain information on the electronic structure of metal to magnetic-semiconductor interfaces. We describe the techniques of spin polarization measurements in field emission. The measurement of Kisker et al. on ferromagnetic EuS evaporated on W are discussed along with recent investigations on Ni.     

超高压下碳结构的第一性原理研究

采用第一性原理密度泛函理论,结合平面波赝势和广义梯度近似(GGA)方法计算了多种碳结构在超高压条件下的热力学稳定性及晶体结构性质.计算结果表明,碳结构的质量密度和基态能量与其对称性高低没有很强的依赖关系;在超高压条件下,随着压强的增加,热力学相对稳定的碳结构依次是石墨、金刚石、BC-8和SC碳结构,Clark等人所提出的R8结构并不是一种真正的高压稳定碳结构.     

Statistical multistep compound reactions — with renormalized exciton state densities

The master equation which takes into account angular momentum considerations is used to obtain the emission spectra for statistical multistep compound reactions. Realistic wave functions are used to evaluate the radial integrals appearing in the escape and spreading widths. The renormalized particle hole state density of Akkermans et al. is used in the calculations. The improvements over the one component formulation are discussed.     

Colossal dielectric constant in high entropy oxides

Entropic contributions to the stability of solids are very well understood and the mixing entropy has been used for forming various solids, for instance such as inverse spinels, see Nawrotsky et al., J. Inorg. Nucl. Chem. 29 , 2701 (1967) [1]. A particular development was related to high entropy alloys by Yeh et al., Adv. Eng. Mater. 6 , 299 (2004) [2] and Cantor et al., Mater. Sci. Eng. A 375–377 , 213 (2004) [3] (for recent reviews see Zhang et al., Prog. Mater. Sci. 61 , 1 (2014) [4] and Tsai et al., Mater. Res. Lett. 2 , 107 (2014) [5]) in which the configurational disorder is responsible for forming simple solid solutions and which are thoroughly studied for various applications especially due to their mechanical properties, e.g. Gludovatz et al., Science 345 , 1153 (2014) [6] and Lu et al., Sci. Rep. 4 , 6200 (2014) [7], but also electrical properties, Kozelj et al., Phys. Rev. Lett. 113 , 107001 (2014) [8], hydrogen storage, Kao et al., Int. J. Hydrogen Energy 35 , 9046 (2010) [9], magnetic properties, Zhang et al., Sci. Rep. 3 , 1455 (2013) [10]. Many unexplored compositions and properties still remain for this class of materials due to their large phase space. In a recent report it has been shown that the configurational disorder can be used for stabilizing simple solid solutions of oxides, which should normally not form solid solutions, see Rost et al., Nature Commun. 6 , 8485 (2015) [11] these new materials were called ”entropy‐stabilized oxides”. In this pioneering report, it was shown that mixing five equimolar binary oxides yielded, after heating at high temperature and quenching, an unexpected rock salt structure compound with statistical distribution of the cations in a face centered cubic lattice. Following this seminal study, we show here that these high entropy oxides (named HEOx hereafter) can be substituted by aliovalent elements with a charge compensation mechanism. This possibility largely increases the potential development of new materials by widening their (already complex) phase space. As a first example, we report here that at least one HEOx composition exhibits colossal dielectric constants, which could make it very promising for applications as large‐k dielectric materials. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Determination of Spatial Distribution of Plasma Electrons by Multibeam FIR Interferometry

The spatial distribution of plasma electrons in the ISX-B Tokamak has been determined by Abel-inverting vertical integral data from far infrared (FIR) laser-phase shift measurements. The calculational method for performing the Abel inversion is discussed and the results of the inversion of several sets of data are compared with Thomson scattering measurements of the pointwise electron density, and with the 2-mm interferometer measurement of the horizontal-midplane line-integral electron density. The inversion method used is essentially that described by Demas et al. This method is an extension of the method described by Yasutomo et al. The main difference is that the inversion method used here can treat plasmas with any outer boundary shape as long as the radius of the surface is single valued. In this regard it is more general than the inversion method of Wetzer, which is restricted to using an elliptical outer-plasma boundary.     

基于可调控多肽纳米管和石墨烯复合纳米结构的光吸收催化平台

近年来, 自组装纳米结构因为其容易制备、稳定、环保以及与各种功能基团、粒子等的多样结合能力吸引了科学家们的目光, 成为人们研究的热点课题, 在光电池、光催化、水凝胶、药物缓释等方面的实验科学领域得到了广泛的应用. 尤其是光催化方面, 自组装结构的重复性为激子的传递创造了比较良好的条件, 成为众多激子传递平台中的佼佼者. 本文报道了一种以苯丙氨酸二肽纳米管和羧基石墨烯为基础的自组装光吸收催化平台, 对其结构进行研究, 并使用该体系进行了烟酰胺腺嘌呤二核苷酸到它的还原态的催化实验. 该体系的微观结构由纳米管和石墨烯膜复合而成, 羧基石墨烯的存在能够降低纳米管直径, 实现纳米管的形态操控, 石墨烯与多肽纳米管复合纳米结构的存在实现了多通道协同激子传递, 降低了激子传递的距离, 极大增强了催化中心对于激子的接受和使用效率. 在复合了光敏剂和催化中心之后, 该体系具有较高的稳定性, 均一的分散性, 很强的光能吸收和转化能力等性质. 对于从NADP⁺往NADPH转变的催化实验表明, 该体系有较高的反应速率和催化效率, 并且比两种单一结构催化平台效果之和更好, 实现了一加一大于二的效应, 展现了复合纳米结构光吸收催化平台的巨大潜力和广阔应用前景.     

On the estimation of dynamic mass density of random composites

The dynamic effective mass density and bulk modulus of an inhomogeneous medium at low frequency limit are discussed. Random configurations in a variety of two-dimensional physical contexts are considered. In each case, effective dynamic mass density and bulk modulus are calculated based on eigenmode matching theory. The results agree with those provided by Martin et al. [J. Acoust. Soc. Am. 128, 571-577 (2010)] obtained from effective wavenumber method.     

具有广阔应用前景的纳米金刚石膜

纳米金刚石膜的制备、表征和应用研究已经成为CVD金刚石膜研究领域的一个新的热点．文章重点介绍了Gruen等人在贫氢和无氢环境中制备纳米金刚石膜的开创性工作,并和在富氢气氛中制备的纳米金刚石膜进行了对比评述．对纳米金刚石膜的表征技术和应用前景进行了讨论．     

ON THE SPONTANEOUS PION EMISSION BY HEAVY NUCLEI

In this paper a method of detecting the pionic nuclear radio-activity discussed by Ion et al.is proposed using in clusive high energy gamma ray measurement.Taking the maximum pion energy given by Ion et al,the energy ranges of the gamma rays from the emitted π⁰ mesons are calculated.