大蹼铃蟾多肽及其制备方法和在制药中的应用

本发明属于生物医学领域。大蹼铃蟾多肽是从中国两栖类动物大蹼铃蟾皮肤分泌物中分离得到的一种单链多肽，分子量2698.4，等电点10.0，多肽全序列一级结构为：NH2—TITTKKLSGLKTALKGAAKELASTYT—COOH。制备方是将活体大蹼铃蟾用水清洗干净，置于带盖的玻璃容器中，滴加无水乙醚，密闭容器3—5分钟，可见大量的泡沫状物质从大蹼铃蟾皮肤分泌出来，收集分泌物，离心去除沉淀、冷冻干燥后，经离子交换、凝胶过滤、高压液相反相柱层析分离纯化后得到。具有显著的抑制细菌和真菌生长、肿瘤细胞生长、和抗艾滋病病毒活性的作用。适用于制备抗微生物感染、抗肿瘤、抗艾滋病药物。

我国中药来源的抗HIV天然化合物研究进展

由于迄今仍无艾滋病(acquired immunodeficiency syndrome,AIDS)疫苗问世,抗人类免疫缺陷病毒(human immunodeficiency virus,HIV)药物仍然是艾滋病治疗的主要手段。传统中药和药用植物来源的天然化合物具有结构多样性、毒性较低、来源广泛等特点,因而在防治艾滋病方面有着独特的优势和巨大的潜力。研究者已经对天然化合物抗HIV作用进行了大量研究,并取得了可喜的成绩,发现了一些生物碱、香豆素、木脂素、黄酮类、萜类、鞣质类、多糖类、蛋白质和多肽类等天然化合物具有抗HIV的活性。然而,多数研究都是在体外试验完成的,大多数天然化合物体外抗HIV活性偏低,而且抗HIV的靶点仍不十分清楚。本文结合笔者实验室研究工作,重点介绍近年来我国传统中药来源的抗HIV活性较强的天然化合物研究进展。

Learning large-scale spatial relationships in a maze and effects of MK-801 on retrieval in the rhesus monkey

Monkeys have strong abilities to remember the visual properties of potential food sources for survival in the nature. The present study demonstrated the first observations of rhesus monkeys learning to solve complex spatial mazes in which routes were guid

State estimation over a communication network: Measurement or estimate communication?

In this paper we consider the problem of state estimation over a communication network. Using estimation quality as a metric, two communication schemes are studied and compared. In scheme one, each sensor node communicates its measurement data to the remote estimator, while in scheme two, each sensor node communicates its local state estimate to the remote estimator. We show that with perfect communication link, if the sensor has unlimited computation capability, the two schemes produce the same estimate at the estimator, and if the sensor has limited computation capability, scheme one is always better than scheme two. On the other hand, when data packet drops occur over the communication link, we show that if the sensor has unlimited computation capability, scheme two always outperforms scheme one, and if the sensor has limited computation capability, we show that in general there exists a critical packet arrival rate, above which scheme one outperforms scheme two. Simulations are provided to demonstrate the two schemes under various circumstances. © South China University of Technology and Academy of Mathematics and Systems Science, CAS and Springer-Verlag Berlin Heidelberg 2010.

大型水电站对河流底栖藻类群落的影响

2004年9月—2007年6月,对古夫河受大型水电站影响的GF04样点及高岚河的参照样点GL03进行逐月采样,研究了大型水电站对古夫河底栖藻类的影响.结果表明:研究期间,两样点主要理化指标差异均不显著(P>0.05);两样点水动力学差异显著(P<0.05),研究期间GL03样点基本处于缓流状态,其季节变化显著(P<0.05),而GF04样点由于受水库放水影响,采样期间60%以上时间处于急流状态,没有明显的季节节律,说明水动力学及生境的变化是影响研究区底栖藻类群落的重要因素;群落相似性以及非着生型硅藻、直立

强壮粗体虫寄生引起的鳜肠道病理

强壮粗体虫是鳜肠道最常见寄生蠕虫。通过光镜及电镜对自然感染强壮粗体虫的鳜肠道进行了组织病理观察。强壮粗体虫的寄生引起鳜肠上皮细胞脱落、肠固有膜层结缔组织增生及白细胞向病灶处浸润 ,并可观察到嗜酸性粒细胞附着在与肠上皮及固有膜接触的虫体的体壁及吻部。在虫体吻部与肠固有膜层接触处依次观察到纤维细胞、成纤维细胞、嗜酸性粒细胞等 ,其中嗜酸性粒细胞又可分为未成熟嗜酸性粒细胞、成熟的嗜酸性粒细胞及正在脱颗粒的嗜酸性粒细胞。另外在肠壁的固有膜层观察到包裹虫体的结缔组织纤维囊 ,囊壁由三层结构构成 ,同时在鳜肠壁相同的

Ultrafast dynamics of exciton formation in semiconductor nanowires.

The dynamics of free electron-hole pairs and excitons in GaAs-AlGaAs-GaAs core-shell-skin nanowires is investigated using femtosecond transient photoluminescence spectroscopy at 10 K. Following nonresonant excitation, a bimolecular interconversion of the initially generated electron-hole plasma into an exciton population is observed. This conducting-to-insulating transition appears to occur gradually over electron-hole charge pair densities of 2-4 × 10(16) cm(-3) . The smoothness of the Mott transition is attributed to the slow carrier-cooling during the bimolecular interconversion of free charge carriers into excitons and to the presence of chemical-potential fluctuations leading to inhomogeneous spectral characteristics. These results demonstrate that high-quality nanowires are model systems for investigating fundamental scientific effects in 1D heterostructures.

简评美国公布的15个AES候选算法

文章对美国国家标准和技术研究所（ＮＩＳＴ）最近公布的１５个ＡＥＳ候选算法的基本设计思想作了简要介绍，同时也介绍了对这些算法的最新分析结果

谓词μ演算和模态图的语义一致性

模态图是谓词μ演算的一种有效的图形表示形式。证明了谓词μ演算和模态图的语义一致性，详细讨论了谓词μ演算公式、嵌套谓词等式系和模态图之间的关系，并给出了一种优化的从线性公式到嵌套谓词等式系的转换算法。