Aptamer and its applications in neurodegenerative diseases

Aptamers are small single-stranded DNA or RNA oligonucleotide fragments or small peptides, which can bind to targets by high affinity and specificity. Because aptamers are specific, non-immunogenic and non-toxic, they are ideal materials for clinical applications. Neurodegenerative disorders are ravaging the lives of patients. Even though the mechanism of these diseases is still elusive, they are mainly characterized by the accumulation of misfolded proteins in the central nervous system. So it is essential to develop potential measures to slow down or prevent the onset of these diseases. With the advancements of the technologies, aptamers have opened up new areas in this research field. Aptamers could bind with these related target proteins to interrupt their accumulation, subsequently blocking or preventing the process of neurodegenerative diseases. This review presents recent advances in the aptamer generation and its merits and limitations, with emphasis on its applications in neurodegenerative diseases including Alzheimer’s disease, Parkinson’s disease, transmissible spongiform encephalopathy, Huntington’s disease and multiple sclerosis.     

低碳约束下青岛市就业结构评价与优化研究

在国家提出发展低碳经济的背景下,为了分析低碳约束下青岛市就业结构优化水平,选取青岛市9个行业2004-2015年的数据,通过面板数据模型研究不同行业碳排放强度和就业结构之间的关系。结果表明,青岛市同行业自身的碳排放强度存在差异,与就业人口的关系也存在较大差异。最后根据评价结果,提出调整能源结构、寻找绿色经济增长点以及促进绿色就业从而实现低碳约束下就业结构优化的建议。     

Liquid marbles.

The transport of a small amount of liquid on a solid is not a simple process, owing to the nature of the contact between the two phases. Setting a liquid droplet in motion requires non-negligible forces (because the contact-angle hysteresis generates a force opposing the motion), and often results in the deposition of liquid behind the drop. Different methods of levitation-electrostatic, electromagnetic, acoustic, or even simpler aerodynamic techniques-have been proposed to avoid this wetting problem, but all have proved to be rather cumbersome. Here we propose a simple alternative, which consists of encapsulating an aqueous liquid droplet with a hydrophobic powder. The resulting 'liquid marbles' are found to behave like a soft solid, and show dramatically reduced adhesion to a solid surface. As a result, motion can be generated using gravitational, electrical and magnetic fields. Moreover, because the viscous friction associated with motion is very small, we can achieve quick displacements of the droplets without any leaks. All of these features are of potential benefit in microfluidic applications, and also permit the study of a drop in a non-wetting situation-an issue of renewed interest following the recent achievement of super-hydrophobic substrates.     

NiO nanosheet assembles for supercapacitor electrode materials

In this paper, large scale hierarchically assembled Ni O nanosheets have been favorably fabricated through a facile hydrothermal route. The as-prepared Ni O nanosheet assembles were characterized in detail by various analytical techniques. The results showed these nanosheets present the thickness of about 30 nm and the surface area is 116.9 m~2 g~(-1). These NiO nanosheet assembles were used as the working electrode materials in electrochemical tests, which demonstrated a specific capacitance value of 81.67 Fg ~(-1)at the current density of 0.5 Ag~(-1)and excellent long cycle-life stability with 78.5% of its discharge specific capacitance retention after 3000 cycles at the current density of 0.5 Ag~(-1), revealing the as-synthesized NiO nanosheet assembles might be a promising electrode material for supercapacitor applications.     

大型二维装箱问题及其禁忌算法研究

对大型二维装箱问题进行描述,提出求解该问题的禁忌算法.算法基于自然数编码,设计了货物的摆放规则和序列生成方式,采用二种邻域,根据邻域的不同,构造了两种禁忌表.算法采用惩罚函‘数处理空间利用率约束.介绍算法的原理,给出了具有代表性算例试验结果并且进行了分析.试验结果表明了提出的禁忌算法对优化大型二维装箱问题的有效性.     

遥感地表参数反演中的一种不确定性知识处理方法

在基于贝叶斯网络的遥感参数反演模型中引入虚拟节点,提出不确定性知识表示与知识更新方法,推导了遥感反演中的参数后验信息更新公式.用北京顺义遥感实验的多尺度数据对冬小麦的叶面积指数和叶绿素面质量进行反演计算,验证了多知识源反演过程中不确定性知识对参数后验分布概率的调整模式.     

星的全着色和计数

超图H的全着色是指同时给图中的顶点和超边进行着色,使相关联或相邻的元素间着不同的颜色,满足这一条件的最少色数就称为全色数,记为χT(H).超图的全着色又可以分成弱全着色和强全着色两种情况.本篇文章主要讨论超图中星形图S(v)的弱全着色和强全着色,并给出相应的弱全色数和强全色数,χWT(S(v))=Δ 1,χST(S(v))=M 1,以及有关全色数计数的相关结论.     

功能化聚丙烯酸酯乳液的表面改性及产物性能

丙烯酸酯单体添加量达到70%时,加入γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)与剩余单体发生共聚制备表面SiOH功能化聚丙烯酸酯乳液(PAES),产物与正硅酯乙酯(TEOS)发生溶胶-凝胶反应,制备PAES/SiO2杂合乳液.透射电镜分析显示,乳胶粒表面被一层无机硅覆盖.傅里叶变换红外光谱结果表明,KH570与丙...     

基于维基语义的多文档文摘研究

多文档文摘作为自然语言处理领域的重要技术之一,能从不同角度辅助用户实现高效的信息获取.由于文档集合内的内容往往来自不同的信息源,文本之间通常存在丰富而复杂的语义关系.常用的基于词的文档表示法,难以为文摘的语义分析过程提供充足而准确的数据信息.为此,我们提出使用维基百科——当今世界最大的在线概念语料库——为多文档文摘的提取提供语义支持.一方面,我们通过提取文档中的维基概念,生成准确一致的句子表示形式.另一方面,在计算句子特征时,我们利用维基词条的首段指导机器文摘的提取.我们首先通过计算概念在维基中的全局相关性和当前文档集内的局部相关性,获取概念的权重.然后在维基概念表示的基础上,为文档中的句子提取多种基于维基的特征,并最后用于文摘生成.在实验中,我们依次用各个维基特征独立生成文摘,并使用ROUGE(Recall-Oriented Understudy for Gisting Evaluation,面向召回率的要点评估)指标评价文摘质量.通过比较,实验验证了维基词条首段能较好的提升文摘质量.     

The ribosome uses two active mechanisms to unwind messenger RNA during translation

The ribosome translates the genetic information encoded in messenger RNA into protein. Folded structures in the coding region of an mRNA represent a kinetic barrier that lowers the peptide elongation rate, as the ribosome must disrupt structures it encounters in the mRNA at its entry site to allow translocation to the next codon. Such structures are exploited by the cell to create diverse strategies for translation regulation, such as programmed frameshifting, the modulation of protein expression levels, ribosome localization and co-translational protein folding. Although strand separation activity is inherent to the ribosome, requiring no exogenous helicases, its mechanism is still unknown. Here, using a single-molecule optical tweezers assay on mRNA hairpins, we find that the translation rate of identical codons at the decoding centre is greatly influenced by the GC content of folded structures at the mRNA entry site. Furthermore, force applied to the ends of the hairpin to favour its unfolding significantly speeds translation. Quantitative analysis of the force dependence of its helicase activity reveals that the ribosome, unlike previously studied helicases, uses two distinct active mechanisms to unwind mRNA structure: it destabilizes the helical junction at the mRNA entry site by biasing its thermal fluctuations towards the open state, increasing the probability of the ribosome translocating unhindered; and it mechanically pulls apart the mRNA single strands of the closed junction during the conformational changes that accompany ribosome translocation. The second of these mechanisms ensures a minimal basal rate of translation in the cell; specialized, mechanically stable structures are required to stall the ribosome temporarily. Our results establish a quantitative mechanical basis for understanding the mechanism of regulation of the elongation rate of translation by structured mRNAs.