EFFECTS OF CHANGES IN PATTERN OF LHRH PULSE ON LH SECRETION BY PERFUSED ANTERIOR PITUITARY CELLS OF MALE RATS

In the present study, a perfusion system of dispersed cells was used to investigate theeffects of LHRH pulse amplitude and frequency, and LHRH continuous stimulation on LHsecretion by anterior pituitary cells of adult male rats. The results have shown that, in therange of LHRH concentrations from 1×10~(-10) to 1 ×10~(-6) mol/L, the dose-response curve of LHsecretion was linear. LHRH pulse frequency generated a biphasic LH response: increasingLHRH pulse frequency increased the basal LH secretion and decreased LH/pulse. When1 ×10~(-9), mol/L or greater LHRH was given at frequencies of 3 pulses/h or higher, it wasobserved that a maximal LH peak was induced and then the LH release declined progres-sively to its LH basal level, i.e. LHRH self-priming effect and LH desensitization occurred.Enhancement of amplitude of LHRH pulses could reduce pulse frequency required for prim-ing. Increases in frequency of LHRH pulses with high amplitude would provoke the prim-ing effect more quickly. In addition, continuou     

Deficiency of glutaredoxin 5 reveals Fe-S clusters are required for vertebrate haem synthesis

Iron is required to produce haem and iron-sulphur (Fe-S) clusters, processes thought to occur independently. Here we show that the hypochromic anaemia in shiraz (sir) zebrafish mutants is caused by deficiency of glutaredoxin 5 (grx5), a gene required in yeast for Fe-S cluster assembly. We found that grx5 was expressed in erythroid cells of zebrafish and mice. Zebrafish grx5 rescued the assembly of grx5 yeast Fe-S, showing that the biochemical function of grx5 is evolutionarily conserved. In contrast to yeast, vertebrates use iron regulatory protein 1 (IRP1) to sense intracellular iron and regulate mRNA stability or the translation of iron metabolism genes. We found that loss of Fe-S cluster assembly in sir animals activated IRP1 and blocked haem biosynthesis catalysed by aminolaevulinate synthase 2 (ALAS2). Overexpression of ALAS2 RNA without the 5' iron response element that binds IRP1 rescued sir embryos, whereas overexpression of ALAS2 including the iron response element did not. Further, antisense knockdown of IRP1 restored sir embryo haemoglobin synthesis. These findings uncover a connection between haem biosynthesis and Fe-S clusters, indicating that haemoglobin production in the differentiating red cell is regulated through Fe-S cluster assembly.     

Synthesis of thiourea derivatives as CCR4 antagonists

A series of thiourea derivatives have been synthesized. Their structures were confirmed by MS and 1H NMR. Several compounds showed potent activities as antagonists of CCR4 receptor.     

Femtosecond Laser Induced Rewritable Optical Memory in Silicate Glasses

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河北省财政支持中等职业教育发展研究

近年来,河北省中等职业教育虽然有了长足发展,但依然存在教育资金投入不足、结构失衡等问题.为了全面贯彻落实<国务院关于大力发展职业教育的决定>、<河北省人民政府关于进一步推进职业教育发展的意见>,推动河北省中等职业教育发展,更好地适应经济发展、社会主义新农村建设和全面小康社会建设对高素质劳动者和技能人才的迫切需要,河北省要加大对中等职业教育的支持力度,改革财政投入方式,提高资金使用效率.     

实现中国动画民族化道路探析——戏曲动画探究

戏曲动画最大程度地集中了戏曲和动画这两门综合艺术的审美特性,从而构成了一种非常特别的艺术形式。动画填补了戏曲在形式和传播等方面的不足,戏曲推动着中国动画产业的发展,为动画产业开辟了一个新的发展领域,为动画片的创作提供了大量题材,使动画片有了更新颖的内容。     

Proton antenna effect of the gamma-cyclodextrin outer surface, measured by excited state proton transfer

The reversible proton dissociation and geminate recombination of the common photoacid, 8-hydroxypyrene-1,3,6-trisulfonate (pyranine), either in dilute aqueous solution or when forming a complex with gamma-cyclodextrin (gamma-CD), has been studied by time-resolved fluorescence spectroscopy and supplemented by molecular modeling and dynamics simulations. We find that the dissociation rate of the proton from the excited molecule was decreased to about approximately 50% of its value in water, while the rate of recombination was doubled. These observations were evaluated by molecular modeling of the reactants at atomic resolution. The combination of the two methodologies indicates that the pyranine in the complex can assume more than one level of interaction with the solvent. The polysugar torus surrounding the pyranine perturbs the hydrogen bond in the dye's immediate vicinity and deforms the electrostatic potential inside the Coulomb cage, causing major deviations from a simple spheric symmetry. These observations can account for the special kinetic features measured for the complex. We suggest that this system can be used as a basic model for evaluating the mechanism of proton transfer in non-homogeneous systems, such as the surface of proteins or biomembranes.     

湖南省高校档案工作现状分析及其发展对策研究

分析了目前湖南省高校档案工作现状,指出了其存在的问题,提出了解决问题的对策.     

激光诱导玻璃内部金纳米颗粒的析出及光谱

使用钛宝石飞秒激光引发和热处理相结合，实现了在含有金离子的硅酸盐玻璃内部，有空间选择性地析出金纳米颗粒。对吸收光谱的研究表明，随着热处理温度的升高，吸收峰强度增大且红移；随着激光功率密度的增大，金纳米颗粒也增大。在特定的激光和热处理条件作用下，可以在玻璃内部有空间选择性的使金离子还原后聚集，形成金纳米颗粒，具有量子尺寸效应。改变激光功率和热处理温度可以控制所析出的金属纳米粒子的尺寸，从而实现多色显示，飞秒激光诱导金纳米颗粒具有稳定性，颜色具有持久性。     

河北省流通领域农民合作经济组织发展研究

进入农业发展新阶段,农业面临的问题和挑战不再是农产品短缺,而是在国内农产品买方市场的条件下,农业生产者所面临的风险从生产领域转向市场流通领域;同时,在我国农产品市场进一步开放背景下,农产品国内国际大流通的基本格局已经形成.由此导致小生产与大市场的矛盾更加突出,市场流通越来越成为农业发展和农民增收的瓶颈.本文通过河北的实践证明在我国将长期坚持家庭承包经营体制不变的前提下,解决这一矛盾的根本途径就是实现农民在流通领域的组织化,即建立流通领域农民合作经济组织.