蛙虹彩病毒cop基因的克隆表达及亚细胞定位

从蛙虹彩病毒(Rana gryliovirus,RGV)基因组中克隆了含凋亡相关结构域的新基因-cop(Caspaserecruit ment domain only protein,COP)基因的全部编码区,成功构建了重组表达载体,进行了原核表达,并在鲤鱼上皮瘤细胞(Epithelioma papulosumcyprini,EPC)中进行了亚细胞定位.序列分析表明,RGVcop基因全长288 bp,编码一个长为95 aa,分子量为10.4×103的推定蛋白.二级结构预测表明其含有5个α螺旋.同源性比对分析显示,RGVcop与其他6株虹彩病毒及人类cop相关蛋白同源性最高为94%,最低为33%.重组原核表达质粒pET28a-COP转化大肠杆菌BL21后,经IPTG诱导表达,获得一条约14×103的融合蛋白.重组真核表达质粒pEGFPN3-COP转染EPC细胞,经DAPI染色后,在荧光显微镜下观察显示重组蛋白在整个细胞中均有分布.     

Effects of UV photon irradiation on SiOx (0 < x < 2) structural properties

Thin films of a-SiO_x (0 < x < 2) were prepared by reactive r.f. magnetron sputtering from a polycrystalline-silicon target in an Ar/O₂ gas mixture. The oxygen partial pressure in the deposition chamber was varied so as to obtain films with different values of x. The plasma was monitored, during depositions, by optical emission spectroscopy (OES) system. Energy dispersive X-ray (EDX) measurements and infra-red (IR) spectroscopy were used to study the compositional and structural properties of the deposited layers.Structural modifications of SiO_x thin films have been induced by UV photons’ bombardment (wavelength of 248 nm) using a pulsed laser. IR spectroscopy and X-ray photoemission spectroscopy (XPS) were used to investigate the structural changes as a function of x value and incident energy. SiO_x phase separation by spinodal decomposition was revealed. The IR peak position shifted towards high wavenumber values when the laser energy is increased. Values corresponding to the SiO₂ material (only Si⁴⁺) have been found for laser irradiated samples, independently on the original x value. The phase separation process has a threshold energy that is in agreement with theoretical values calculated for the dissociation energy of the investigated material.For high values of the laser energy, crystalline silicon embedded in oxygen-rich silicon oxide was revealed by Raman spectroscopy.     

Polarization inscription in ferroelectric (111) PZT and (100) SBT films

Ferroelectric thin films form an equilibrium domain structure compatible with their respective crystallographic symmetry. In tetragonal (111) PZT, 90° domains prevail; in (pseudo-tetragonal) (100) SBT both 90° and 180° domains are present. The size of 90° domains has been measured for e.g., PZT as slabs of 15 nm width. Domain size is a result of stress minimization in the film during the paraelectric (PE) → ferroelectric (FE) transition. A precise and regular domain pattern for (111) PZT and (100) SBT films has been investigated in detail by TMSFM. Single domains can be addressed mechanically with the tip of an AFM. Such single domain switching corresponds to a data storage density of 200 Gbit/inch². Applications of ferroelectric and high- paraelectric materials for e.g., non-volatile data storage replacing DRAM devices or as sensors in infrared cameras are increasingly becoming popular.     

Steady state analysis of an M/G/1 queue with two phase service and Bernoulli vacation schedule under multiple vacation policy

This paper examines the steady state behaviour of a batch arrival queue with two phases of heterogeneous service along and Bernoulli schedule vacation under multiple vacation policy, where after two successive phases service or first vacation the server may go for further vacations until it finds a new batch of customer in the system. We carry out an extensive stationary analysis of the system, including existence of stationary regime, queue size distribution of idle period process, embedded Markov chain steady state distribution of stationary queue size, busy period distribution along with some system characteristics.     

Mössbauer spectroscopy study of spin structure and its in-field and temperature dynamics in B2 ordered Fe(Al) alloys

The experimental data from Mössbauer spectroscopy and magnetic measurements are presented as functions of the temperature and external magnetic field for a B2-type ordered Fe ₆₆ Al ₃₄ alloy.     

Chain length effect on dynamical structure of poly (vinyl pyrrolidone)-polar solvent mixtures in dilute solution of dioxane studied by microwave dielectric relaxation measurement

Dielectric relaxation study of the binary mixtures of poly(vinyl pyrrolidone) (PVP) (Mw=24000, 40000 and 360000 g mol⁻¹) with ethyl alcohol (EA) and poly(ethylene glycol)s (PEGs) (Mw=200 and 400 g mol⁻¹) in dilute solutions of dioxane were carried out at 10.1 GHz and 35°C. The relaxation time of PVP-EA mixtures was interpreted by the consideration of a wait-and-switch model in the local structure of self-associated ethyl alcohol molecules and also the PVP chain length as a geometric constraint for the reorientational motion of ethyl alcohol molecules. The formation of complexes and effect of PVP chain length on the molecular dynamics, chain flexibility and stretching of PEG molecules in PVP-PEG mixtures were explored from the comparative values of dielectric relaxation time. Further, relaxation time values in dioxane and benzene solvent confirm the viscosity independent molecular dynamics in PVP-EA mixtures but the values vary significantly with the non-polar solvent environment.     

Exciton reflectivity of GaAs/Ga1−x Al x As multiple quantum wells

Summary The normal incidence reflectivity spectrum of excitons in GaAs/Ga_1−x Al _x As multiple quantum wells is calculated within the local response approximation. It is shown that the reflectivity lineshape strongly depends on the sample geometry. Using realistic parameters of a multiple quantum well structure, we obtain an excellent fit of the experimental reflectivity curve, thus giving exciton energies, oscillator strengths and exciton broadening parameters.

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Riassunto Lo spettro di riflettività ad incidenza normale degli eccitoni nei pozzi quantistici multipli di GaAs/Ga_1−x Al _x As è calcolato nell’ambito dell’approssimazione locale. Si mostra con la forma della linea di riflettività dipende in gran misura dalla forma geometrica del campione. Usando parametri realistici di una struttura a pozzi quantistici multipli, si ottiene un’ottima approssimazione della curva di riflettività sperimentale, che fornisce così energie eccitoniche, forze dell’oscillatore e parameri di ampliamento eccitonico.

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Резюме В рамках приближения линейного отклика вычисляется спекрт отражательной способности экситонов при нормальном падении для множественных квантовых ям в GaAs/Ga_1−x Al _x As. Показывается, что форма линии отражательной способности сильно зависит от геометрии образца. Используя реалистические параметры структуры множественных квантовых ям, мы получаем хорошее соответствие с экспериментальной кривой для отражательной способности. Получаются энергии экситонов, силы осцилляторов и парам⪟тры экситонного уширения.

     

Organometallic complexes with biological molecues,part 3. in vivo cytotoxicity of diorganotin (IV) chloro and triorganotin (IV) chloro derivatives of penicillin g on chromosomes of aphanius fasciatus (pisces,cyprinodontiformes)

In order to obtain a continuous source of mitotic metaphases, gill tissue of Aphaius fasciatus (Pisces, Cyprinodontiformes) has been successfully employed. Results gathered after exposure of fish to R₂SnClpenG, R₃SnClpenGNa, to the parents R₂SnCl₂, R₃SnCl and to penGNa (penGNa = penicillinGNa; R = methyl, butyl and phenyl) suggest that both the parent organotin (IV) chloride and organotin (IV) chloropenG derivatives are toxic while penGNa exerts no significant toxic activity. Essentially, all of the chromosome abnormalities are classifiable as irregularly staining of chromosomes, breakages, side-arm bridges or pseudochiasmata.     

多孔硅发光机制的分析

从量子力学的基本理论出发讨论了量子限制效应，推导出多孔硅有效禁带宽度增量并用量子限制效应和表面态及其物质在发光中作用的理论解释了ＰＳ光致发光的实验现象。     

电子通道技术在YBa2Cu3O7外延超导薄膜研究中的应用

本研究采用电子通道技术（ＥＣＰ）对单晶和双晶外延生长的ＹＢａ＿２Ｃｕ＿３Ｏ＿７（ＹＢＣＯ）超导薄膜的结构、取向和表面完好性作检测，并证实对衬底的预处理可改善外延超导薄膜的质量；还对ＹＢＣＯ／ＣｅＯ＿２／ＭｇＯ／ＳｒＴｉＯ３的双外延薄膜作研究。