HSF2 mRNA 在热应激和大剂量11酸睾酮诱导恒河猴生精细胞凋亡中的表达变化

为了探讨 HSF2 mRNA 在热应激和超生理剂量睾酮诱导恒河猴生精细胞凋亡中的表达变化, 作者建立了手术诱导单侧隐睾和注射大剂量11酸睾酮(TU)恒河猴动物模型, 应用3′末端标记分析(TUNEL)和原位杂交方法, 检测睾丸细胞的凋亡信号和 HSF2的表达变化. TUNEL 结果显示热应激和超生理剂量睾酮能够诱导生精细胞出现凋亡信号, 它分别于处理后第5天和第30天达到最强, 表明热应激和睾酮干扰精子发生可能是通过生精细胞凋亡的方式来实现的. HSF2 mRNA 水平在生精细胞凋亡早期(凋亡信号达到最强以前)略有降低, 而在凋亡高峰期之后其表达急剧下降. Hsf2基因与作者以前研究的 Hsp70-2基因的表达具有时间上的相关性, 表明 HSF2蛋白可能调控 Hsp70-2基因的表达, 而且 HSF2可能通过多种方式影响精子的发生以及抑制生精细胞的凋亡。

P16蛋白和生精细胞凋亡对热压和11酸睾酮诱导的恒河猴无精子症和少精子症中的作用

探讨了P16蛋白和生精细胞凋亡在热压和11酸睾酮诱导恒河猴无精子症和少精子症中作用间的关系。3^末端标记分析(TUNEL)结果显示热应激和超生理剂量睾酮能够诱导生精细胞出现凋亡信号,它分别于处理后d5和d30达到最强。免疫组化结果显示,热压或TU主要诱导精原细胞和其它生精细胞以及Sertoli细胞P16的表达。P16蛋白的表达在生精细胞凋亡晚期,即隐睾手术d10或注射TUd60后迅速升高并维持高表达,该蛋白在生精细胞凋亡晚期可能通过抑制精原细胞的有丝分裂,扰乱正常的精子发生。

异育银鲫对鱼粉等11种饲料中磷的利用率

于1988年,以三氧化二铬间接指示法,在水温22±2℃条件下,测定了平均体重为55±5g/尾的异育银鲫对鱼粉、肉骨粉、芝麻饼、虾粉、骨粉、菜籽饼、玉米粉、脱氟磷酸氢钙、磷酸二氢钙、磷酸氢钙、磷酸钙的表观消化吸收率。结果表明:异育银鲫对第一、第二、第三磷酸钙的消化吸收率是不同的,分别为81％,65％和32％,此顺序与其溶解性由大到小的顺序一致;在所测试的八种商品饲料中,对骨粉、虾粉和菜籽饼中磷的表观消化吸收率较高,分别为65％,68％和65％;对鱼粉、芝麻饼、肉骨粉三种原料中磷的表观消化吸收率较低,分别是1

Effects of polarization field on formation of two-dimensional electron gas in (0001) and (11(2)over-bar0) plane AlGaN/GaN heterostructures

Photoluminescence (PL) and temperature-dependent Hall effect measurements were carried out in (0001) and (11 (2) over bar0) AlGaN/GaN heterostructures grown on sapphire substrates by metalorganic chemical vapor deposition. There are strong spontaneous and piezoelectric electric fields (SPF) along the growth orientation of the (0001) AlGaN/GaN heterostructures. At the same time there are no corresponding SPF along that of the (1120) AlGaN/GaN. A strong PL peak related to the recombination between two-dimensional electron gas (2DEG) and photoexcited holes was observed at 3.258 eV at room temperature in (0001) AlGaN/GaN heterointerfaces while no corresponding PL peak was observed in (11 (2) over bar0). The existence of a 2DEG was observed in (0001) AlGaN/GaN multi-layers with a mobility saturated at 6000 cm(2)/V s below 80 K, whereas a much lower mobility was measured in (11 (2) over bar0). These results indicated that the SPF was the main element to cause the high mobility and high sheet-electron-density 2DEG in AlGaN/GaN heterostructures. (C) 2004 Elsevier B.V. All rights reserved.

Luminescence study of (11(2)over-bar0) GaN film grown by metalorganic chemical-vapor deposition

Investigations on photoluminescence properties of (11 (2) over bar0) GaN grown on (1 (1) over bar 02) Al2O3 substrate by metalorganic chemical-vapor deposition are reported. Several emission lines not reported before are observed at low temperature. The sharp peak at 3.359 eV is attributed to the exciton bound to the neutral acceptor. Another peak at 3.310 eV represents a free-to-bound, probably a free electron-to-acceptor, transition. The 3.241 and 3.170 eV lines are interpreted as phonon replica lines of the 3.310 eV line. The phonon energy is 70 meV, consistent with the energy of transverse optical E-1 phonon. The optical properties of the lines are analyzed. (C) 2003 American Institute of Physics.

微过氧化酶-11电化学行为的研究

生物分子的电化学行为与生命过程直接相关,通过对生物大分子电子传递反应机理的研究,可获得有关生理过程的重要信息.该论文主要研究内容和结论如下:1.研究了用共价键合法、Nafion膜法、自组装法和吸附法制备的MP-11修饰电极,发现用吸附法来制备MP-11修饰电极有方法简单,稳定性较好的优点.2.首次利用电化学方法研究了赖氨酸和精氨酸与MP-11配位后对MP-11的电化学性能的影响.3.研究了MP-11对NO还原的电催化作用.4.首次用傅立叶变换表面增强拉曼光谱研究了粗糙银电极表面MP-11的结构和吸附方式.5.首次研究了细胞色素c在尼龙膜修饰金电极上的电化学行为.

A multi-standard active-RC filter with accurate tuning system

A low-power, highly linear, multi-standard, active-RC filter with an accurate and novel tuning architec-ture is presented. It exhibits 1EEE 802. 11a/b/g (9.5 MHz) and DVB-H (3 MHz, 4 MHz) application. The filter exploits digitally-controlled polysilicon resistor banks and a phase lock loop type automatic tuning system. The novel and complex automatic frequency calibration scheme provides better than 4 comer frequency accuracy, and it can be powered down after calibration to save power and avoid digital signal interference. The filter achieves OIP3 of 26 dBm and the measured group delay variation of the receiver filter is 50 ns (WLAN mode). Its dissipation is 3.4 mA in RX mode and 2.3 mA (only for one path) in TX mode from a 2.85 V supply. The dissipation of calibration consumes 2 mA. The circuit has been fabricated in a 0.35μm 47 GHz SiGe BiCMOS technology; the receiver and transmitter filter occupy 0.21 mm~2 and 0.11 mm~2 (calibration circuit excluded), respectively.