An important functional group,benzo[1,3]dioxole,of alkaloids induces the formation of the human telomeric DNA G-quadruplex

Over the past few decades, numerous molecules have been discovered or designed to interact efficiently and selectively with a peculiar DNA structure named G-quadruplex. Some of these molecules have been developed as anticancer agents. To aid the design of anticancer agents, the ability of alkaloids possessing Protoberberine and Benzophenanthridine groups to induce the formation of G-quadruplexes were studied using CD spectroscopy. By careful examination of their structures, we found that a benzo[1,3]dioxole group plays an important role in influencing their inductive properties. The more functional groups the alkaloids have, the stronger their G-quadruplex inductive ability.     

Roles of flanking sequences in the binding between unimolecular parallel-stranded G-quadruplexes and ligands

G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug development.As a motif existed in physiological condition,flanking sequences are an important part of G-quadruplexes but the study on the impact of flanking sequences on (G-quadruplex)-ligand binding is rarely reported.In this paper,the effects of flanking sequences on binding affinity between a series of unimolecular parallel-stranded G-quadruplex sequences derived from c-myc oncogene promoter (termed as c-myc G-quadruplexes) and their ligands are discussed in detail.The results showed that the flanking sequences on c-myc G-quadruplexes play key roles in (G-quadruplex)-ligand interaction.When a c-myc G-quadruplex is bound to its ligands,the flanking sequences might form a binding cavity above the terminal G-quartet,which could provide a suitable site for ligands to dock in.Moreover,the bases on flanking sequences could interact with ligand through π-π stacking,and finally form a sandwich-stacking mode (terminal G-quartet,ligand and bases on the flanking sequence).This mode could stabilize the (G-quadruplex)-ligand complex effectively and enhance the binding affinity dramatically.However,flanking sequences are also found to exhibit steric hindrance effect which could impede the (G-quadruplex)-ligand binding.     

Characteristics of Early Eocene radiolarian assemblases of the Sasa area, southern Tibet and their constraint on the closure history of the Tethys

Quantitative analysis of Early Eocene radiolarian assemblages discovered in the sedimentary melange （accretionary prism） of the Saga area, southern Tibet provides new information to constrain the timing of Tethys closure and the initial collision of India and Eurasia. The radiolarian species of Saga include Amphisphaera coronata （Ehrenberg）, Buryella hannae Bak ＆ Barwicz-Piskorz, Buryella clinata Foreman, Buryella tetradica Foreman, Calocycloma ampulla （Ehrenberg）, Lamptonium fabaeforme constrictum Riedel and Sanfilippo, Lamptonium pennatum Foreman, Lithomespilus coronatus Squinabol and Lamptonium （？） colymbus Foreman. The adequate and reliable correlation of these radiolarians specimens indicates that the assemblage is of Early Eocene in age. The age and depositional environment of these radiolarians testify that deep ocean basins existed between India Plate and Asia Plate during the Early Eocene. The complete closure of Tethys must have taken place at least after the Early Eocene.     

工科本科生毕业设计（论文）综合成绩的评定方法

该文就现行工科院校本科毕业设计（论文）现状,选用10个评价指标,由学生综合成绩等级与对应的评价指标关系提炼出5个等级理想评价指标,结合离散Hopfield神经网络的联想记忆能力,建立基于离散Hopfield神经网络的本科毕业设计（论文）综合成绩评定模型;将待评定的学生等级评价指标编码作为模型的输入,利用外积法对网络连接权值进行迭代学习,仿真结果显示,该模型能够快速、准确、直观地评定学生毕业设计（论文）环节的综合成绩。     

基于DNA G-四链体识别的抗肿瘤分子筛选及结构设计研究进展

以生物靶分子为基础进行抗肿瘤药物先导化合物的筛选是抗肿瘤药物研究的热点之一. DNA G-四链体结构的发现和现代分子生物学技术对其与癌症关系的揭示, 为目前抗肿瘤药物研发提供了一个新的契机. 能够诱导DNA形成G-四链体结构或者与G-四链体特异性结合并使之稳定的化合物有望抑制肿瘤细胞的生长, 从而达到抗癌的作用. 以G-四链体为抗癌药物作用靶点对化合物进行筛选和结构设计是目前化学家和生物学家的关注点. 本文旨在针对靶向G-四链体的抗肿瘤分子筛选、结构设计以及抗肿瘤药物开发三个方面的最新研究进展进行综述. 首先, 介绍两种基于G-四链体对其配体结构特异性识别而对化合物进行结构筛选的研究方法: 基于核磁共振进行抗肿瘤化合物筛选方法以及计算机虚拟筛选. 其次, 从化合物与G-四链体之间静电相互作用方面来进行G-四链体配体的结构设计, 主要包括以下4种类型: (1) 原位胺的质子化; (2) 通过杂环芳香族化合物上的N-甲基化; (3) 中心金属离子的存在; (4) 不带电荷的化合物. 最后, 对目前基于G-四链体为抗肿瘤作用靶点、已经走向临床实验的CX-3543, AS1411两个抗肿瘤药物的开发与作用机制进行介绍.     

人类数字、时间和空间加工的关联性与独立性

数字、时间和空间的认知问题是人类认识世界时所面临的根本问题.人脑对这三者的加工均涉及数量的加工.对数字和时间加工来说,研究揭示出二者的加工具有内在联系,但时间加工可能涉及一些特异性的过程;对数字和空间加工来说,除了数字本身具有空间特性之外,二者还表现出了共同的加工特点,但同时也表现出了一定的分离;对时间和空间加工来说,研究发现时间表征也存在空间特点,并且二者的加工相互影响,尤其是人类在加工时间时无法避免无关空间信息的影响.当前有研究者指出,存在着多重数量系统负责数字、时间和空间的加工,也有研究者认为存在着共享的数量系统是这三者加工的基础.未来研究应注重系统地探讨数字、时间和空间的共同机制,探讨其他加工过程的相关性(如运算过程),以及探讨其他相似维度(如声音、亮度等)的加工等.     

基于SMBus的双CPU运煤滚轴温度检测的应用研究

监控煤矿运煤皮带与滚动轴之间的摩擦温度。利用双CPU实现高速数据交换和处理,将主控和数据处理等功能分开执行。利用多个红外测温传感器MLX90614,分别固定在各滚轴附近,其简单的SCK和SDA接口,直接连接于CPU的普通I/O口,各自对应一个不同地址,快速完成滚轴温度检测。利用双端口RAM作为共享数据存储器,两个端口有两套完全独立的控制总线、地址总线和I/O数据总线,可独立读/写任意地址单元,两个CPU共享该存储器,提高了系统的数据传输速率。     

Metabonomics analysis of the urine of rats with Qi deficiency and blood stasis syndrome based on NMR techniques

Metabonomics analysis of the urine of rats with Qi deficiency and blood stasis syndrome has been performed by comparison with those of normal rats based on NMR techniques. The relative contents of formate,creatinine,2-oxoglutarate(2-OG) ,citrate,taurine,trimethylamine-N-oxide(TMAO) ,succinate and hippurate in the urine of the rats with Qi deficiency and blood stasis syndrome have been changed. These results have provided evidence for understanding the mechanism and the therapy of Qi defi-ciency and blood stasis syndrome.