SYNTHESIS AND CHARACTERIZATION OF ALPHA,BETA-TRIINDIUM SUBSTITUTED HETEROPOLYTUNGSTATES

The complexes of alpha,beta-K(a)H(b)XW(9)O(37)(InH2O)(3) . xH(2)O (X = Si, Ge; a+b = 7) were synthesized from their lacunary precursors alpha,beta-XW(9)O(34)(10-) (X = Si, Ge) and characterized by elemental analysis, W-183 NMR, IR and UV spectroscopy and polarography. W-183 NMR spectra of the title complexes consist of two lines with intensity ratio 2:1, as expected for the C-3 nu structure of trisubstituted A alpha- and A beta-Keggin anions.

CRYSTAL AND MOLECULAR STRUCTURES AND MS ANALYSE OF beta-CARBOXYLETHYL (OR alpha-METHYLETHYL) GERMANIUM TRICHLORIDES

This paper reports the results of the crystal and molecular structures, CI-MS and FAB-MS analyse of Cl3GeCH2CH2COOH and Cl3GeCH(CH3)CH2COOH. The characters and active parts of these molecules are also discussed

Genomic cloning, expression and recombinant protein purification of alpha and beta subunits of the allophycocyanin gene (apc) from the cyanobacterium Anacystis nidulans UTEX 625

A genomic fragment encoding alpha(APC) and beta(APC) (i.e., alpha and beta units of the allophycocyanin, APC) from Anacystis nidulans UTEX 625 was cloned and sequenced. This fragment, containing a non-coding sequence of 56 nucleotides in between, was then subcloned into the expression vector pMal-c2 downstream from and in frame with the malE gene of E. coli encoding MBP ( maltose binding protein). The fusion protein was purified by amylose affinity chromatography and cleaved by coagulation factor Xa. alpha(APC) and beta(APC) were then separated from MBP and MBP fusion proteins, respectively, and concentrated by membrane centrifugation. The study provides a method to produce recombinant allophycocyanin subunits for biomedical and biotechnological applications.

Defects in LPE-grown beta-barium borate (beta-BaB2O4) thin films

Morphological defects in beta-barium borate (beta-BBO) thin films grown on Sr2+ -doped alpha-BBO substrates by liquid phase epitaxy (LPE) technique were studied by scanning electron micrograph (SEM), atomic force microscopy (AFM) and optical spectroscopy. The present results indicate that the main defects exit in beta-BBO thin films are microcracks and hollow structure. The formation of microcrack is due to the lattice mismatch and the difference of thermal expansion coefficients between substrate and film. The hollow structure might be caused during the combination of islands, which formed in the initial stage. (C) 2006 Elsevier GmbH. All rights reserved.

Influence of carbon on the thermoluminescence and optically stimulated luminescence of α -Al2O3:C crystals

alpha-Al2O3:C crystal shows excellent thermoluminescence (TL) and optically stimulated luminescence (OSL) properties but the real role carbon plays in this crystal is still not clearly understood so far. In this work, alpha-Al2O3:C crystal doping with different amounts of carbon were grown by the temperature gradient technique, and TL and OSL properties of as-grown crystals were investigated. Additionally, a mechanism was proposed to explain the role of carbon in forming the TL and OSL properties of alpha-Al2O3:C. TL and OSL intensities of as-grown crystals increase with the increasing amount of carbon doping in the crystal, but no shift is found in the glow peak location at 465 K. As the amount of carbon doping in the crystals decreases, OSL decay rate becomes faster. With the increase in heating rate, the integral TL response of as-grown crystals decreases and glow peak shifts to higher temperatures. TL response decrease rate increases with the increasing amount of carbon doping in the crystals. All the TL and OSL response curves of as-grown crystals show linear-sublinear-saturation characteristic, and OSL dose response exhibits higher sensitivity and wider linear dose range than that of TL. The crystal doping with 5000 ppm carbon shows the best dosimetric properties. Carbon plays the role of a dopant in alpha-Al2O3:C crystal and four-valent carbon anions replace the two-valent anions of oxygen during the crystal growth process, and large amounts of oxygen vacancies were formed, which corresponds to the high absorption coefficient of F and F+ centers in the crystals.

Growth of alpha-Al2O3:C crystal with highly sensitive optically stimulated luminescence

In this work. an alpha-Al2O3:C crystal was directly grown by the temperature gradient technique (TGT) using Al2O3 and graphite powders as the raw materials. The optical, optically stimulated luminescence (OSL) properties and dosimetric characteristics of as-grown crystal were investigated. As-grown alpha-Al2O3:C crystal shows strong absorption band at 205, 230 and 256 nm. Three-dimensional thermoluminescence (TL) emission spectrum of the crystal shows a single emission peak at similar to 415 nm. The OSL decay curve can be fitted to two exponentials, the faster component and the slower component. The OSL response of the crystal shows a linear-sublinear-saturation characteristic. As-grown alpha-Al2O3:C crystal shows excellent linearity in the dose range from 5 x 10(-6) to 50 Gy. For doses higher than the saturation dose (100 Gy). the OSL sensitivity decreases as the dose increases. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.

Identification and characterization of a novel splice variant of gonadotropin alpha subunit in the common carp Cyprinus carpio

In this study, an alternative splicing transcript GtH-alpha 291 was identified by RT-PCR, which is 291 nt and exists not only in the pituitary but also in the ovary in common carp Cyprinus carpio. The analysis of GtH-alpha 291 amino acid sequence by the SignalP server predicted that the 'missing segment' might characterize as a signal peptide. In the secretion experiment, GtH-alpha 357 subunit could be secreted out of HeLa cells while GtH-alpha 291 could not, which confirmed the prediction. Co-immunoprecipitation assay proved that GtH-alpha 291 subunit is able to interact with both FSH-beta and LH-beta as GtH-alpha 357 does. This is the first report concerning an alternative splicing transcript of a GtH alpha subunit. Further studies are necessary to elucidate the specific role of this variant in the regulation of gonadal development and sexual maturation. (c) 2007 The Authors.

Luminescence emission originating from nitrogen doping of beta-Ga2O3 nanowires

Nitrogen-doped beta-Ga2O3 nanowires (GaO NWs) were prepared by annealing the as-grown nanowires in an ammonia atmosphere. The optical properties of the nitrogen-doped GaO NWs were studied by measurements of the photoluminescence and phosphorescence decay at the temperature range between 10 and 300 K. The experimental results revealed that nitrogen doping in GaO NWs induced a novel intensive red-light emission around 1.67 eV, with a characteristic decay time around 136 mus at 77 K, much shorter than that of the blue emission (a decay time of 457 mus). The time decay and temperature-dependent luminescence spectra were calculated theoretically based on a donor-acceptor pair model, which is in excellent agreement with the experimental data. This result suggests that the observed novel red-light emission originates from the recombination of an electron trapped on a donor due to oxygen vacancies and a hole trapped on an acceptor due to nitrogen doping.

Yellow luminescence mechanism and persistent photoconductivity in n-GaN single crystal films grown on alpha-Al2O3(0001) substrates by LP-MOCVD

Unintentionally doped and Si-doped single crystal n-GaN films have been grown on alpha-Al2O3 (0001) substrates by LP-MOCVD. Room temperature photoluminescence measurement showed that besides the bandedges, the spectrum of an undoped sample was a broad deep-level emission band peaking from 2.19 to 2.30eV, whereas the spectrum for a Si-doped sample was composed of a dominant peak of 2.19eV and a shoulder of 2.32eV. At different temperatures, photoconductance buildup and its decay were also observed for both samples.. The likely origins of persistent photoconductivity and yellow luminescence, which might be associated with deep defects inclusive of either Ga vacancy(V-Ga)/Ga vacancy complex induced by impurities or N antisite (N-Ga), will be proposed.

beta-delayed fission of Ac-228

The basic process of an exotic decay mode namely P-delayed fission is simply introduced. The progress status of the study in the world is essentialized. The observation of P-delayed fission of Ac-228 is reported. The radium was radiochemically separated from natural thorium. Thin Ra sources in which Ac-228 was got through Ra-228 ->(beta-) Ac-228 were prepared for observing fission fragments from beta-delayed fission Ac-228. They exposed to the mica fission track detectors, and measured by an HPGe gamma-ray detector. The beta-delayed fission events of Ac-228 were observed and its beta-delayed fission probability was found to be (5 +/- 2) x 10(-12).

Search for beta-delayed fission of Ac-228

Radium was radiochemically separated from natural thorium. Thin Ra-228 ->beta Ac-228 sources were prepared and exposed to mica fission track detectors, and measured by an HPGe gamma-ray detector. The beta-delayed fission events of Ac-228 were observed and its beta-delayed fission probability was found to be (5 +/- 2)x10(-12).

Measurement of the inelastic branch of the stellar O-14(alpha,p)F-17 reaction occurring in the explosive burning in Novae and X-ray busters

The inelastic component of the key astrophysical resonance (1(-), E-x=6.15 MeV) in the O-14(alpha,p)F-17 reaction has been studied by using the resonant scattering of F-17+p. The experiment was done at REX-ISOLDE CERN with the Miniball setup. The thick target method in inverse kinematics was utilized in the present experiment where a 44.2 MeV F-17 beam bombarded a similar to 40 mu m thick (CH2)(n) target. The inelastic scattering protons in coincidence with the de-excited 495 keV gamma rays have been clearly seen and they are from the inelastic branch to the first excited state in F-17 following decay of the 1(-) resonance in Ne-18. Some preliminary results are reported.

轻核区质子滴线附近奇异核#beta#延迟质子衰变研究

远离#beta#稳定线的原子核所具有的特性是否与稳定区附近的核的性质相同，一直是核物理学家所关注的问题，实验上通过对缺中子区奇异核#beta#~+延迟粒子衰变的研究，可以精确测定与核性质有关的各个参数，这将对核结构理论研究产生重要的影响。本论文将首先介绍奇异核#beta#~+延迟粒子衰变研究的历史及其理论，接着介绍关于此研究的实验技术，最后详尽阐述对~(19)Na、~(65)Se和~(20)Na的研究

~(153)Er, ~(157)Yb(EC+#beta#~+)衰变纲图的首次建立

用蒸发中子反应产生~(157)Tb和~(153)Er，收集活性样品，作x, #gamma# 单谱及符合谱测量，对~(157)Yb和~(153)Er的(EC+#beta#~+)衰变进行了研究，给出了~(157)Yb及~(153)Er的衰变纲图，其中~(157)Yb的衰变纲图包括25条新#gamma#射线，分析~(157)Yb的衰变纲图，~(153)Er的衰变纲图包括15条#gamma#射线，并指定出~(153)Er半衰变期值，该值与文献给出值符合得很好。指定了~(153)Er的衰变纲图中能级状况

Rapid label-free detection of metal-induced Alzheimer's amyloid beta peptide aggregation by electrochemical method

Amyloid beta peptide plays a critical role in the pathogenesis of Alzheimer's disease (AD). Metal ions are highly enriched in cerebral amyloid deposits in AD and are proposed to be able to mediate A beta conformation. Therefore, a rapid, low-cost, and sensitive detection of metal-induced A beta aggregation and their relation to AD is clearly needed for the clinical diagnosis and treatment. In this report, we study metal-induced A beta aggregation by a rapid, label-free electrochemical method and monitor both the aggregation kinetics and the morphology in the absence or presence of Zn (II) and Cu (II).