DNA介导的功能性纳米组装体及其生物医学应用

利用表面配体对无机纳米材料进行修饰、组装而获得的功能性纳米组装体,具备不同于单分散纳米材料的特殊光学、电学、磁学和热力学等性质,在生物医药领域显示出巨大的应用价值。DNA具有精确的化学结构和精准的分子识别特性,使其作为一种配体在无机纳米材料表面修饰和组装调控方面展现出独特的优势。由DNA配体介导的功能性纳米组装体能够实现组装结构的精准可控调节,拓宽无机纳米材料在生物医药领域的应用前景,可有效提高肿瘤等重大疾病的诊疗效率,推动生命科学的进步和发展。本文对国内外构建DNA介导功能性纳米组装体及其在生物医药领域应用相关的代表性工作进行总结和对比,讨论我国在该领域面临的机遇和挑战,为今后的发展提出建议。     

液体-固体-溶液界面相转移和相分离——一种通用的纳米晶体合成策略

如何在纳米介观尺度范围内实现对材料结构与性能的调控,是纳米材料功能化及其应用的关键。单分散纳米晶指尺寸及形状均一、且在特定介质中具有良好分散能力的纳米材料。基于纳米粒子自身的尺寸效应、表面效应、量子效应,载流子在纳米粒子限制维度空间内的传输具有不同于其它维度材料的特性,展现出许多独特的光学、电学等物理化学性质。同时形状及尺寸严格均一的单分散纳米晶可以通过各种物理化学相互作用进行组装,在纳米器件、量子点激光器、非线性光学、磁介质、催化、功能材料及纳米生物技术等方面具有极为广阔的应用前景。然而由于不同化…     

聚烯烃纳米塑料发展

纳米聚合复合物材料中目前研究较多的是纳米塑料."纳米塑料"是指无机填充物以纳米尺寸分散在通用塑料基体中形成的有机/无机纳米复合材料.在纳米复合材料中,分散相尺寸至少在一维方向小于100nm.由于分散相的纳米尺寸效应、大比表面积和强界面结合,使纳米塑料具有高强度、耐热性、高阻隔性、阻燃性和优良加工性等优异性能,是一种全新的高技术新材料,应用领域广泛.     

尺寸、形貌和结构可控的球形二氧化硅、及其纳米复合二氧化钛、银球颗粒的研发

纳米材料可控制备技术是目前国内外引人注目的一项高新技术。它利用一系列的化学方法，制备适应不同产品所需要的特定尺寸、结构、形状的纳米材料，改变纳米材料研究中的盲目性、随机性，按照人们的意志来设计、组装、构建纳米功能材料。     

纳米粒子标记的免疫层析芯片与生物传感器的研制

针对乙型肝炎、艾滋病、幽门螺旋杆菌、乳腺癌早期诊断的需求,将纳米粒子标记技术,免疫层析芯片技术与生物传感器结合起来,研发相应的高效、灵敏、特异、快速的纳米检测器件.     

有机小分子原位接枝纳米炭黑的工业制备与应用

本项目旨在对高分散多功能接枝炭黑的工业制备、潜在性能特别是纳米效因、产业上的应用开发及由接枝小分子自组装形成的新结构碳材料的基础研究等进行探索，形成一套具有自主知识产权的技术体系。     

光子束超衍射纳米加工技术及应用基础研究

新型纳米加工技术的研究开发是目前国际上关注的热点,是纳米技术、特别是纳米器件获得应用所必须解决的重要问题之一。纳米器件尺寸小型化、结构多样化、集成高度化的发展趋势要求纳米加工技术不仅具有纳米量级的加工分辨能力,而且也能够实现包括从二维到三维复杂纳米结构的加工与器件制备。     

揭秘纳米收音机

纳米技术堪称“下一代科技领袖”最热门的候选者。最激进的倡导者宣称，纳米技术其实就是一套分子制造系统，可以通过机械方法让一个一个分子彼此相连，自动构架出各种各样的结构，最终制造出各种结构复杂的成品。然而，事实却并非如此。“纳米”这个术语已经被过度滥用，几乎任何微小物件都在用“纳米’，这个名字为自己脸上贴金，甚至连机油、防晒霜、唇膏、滑雪蜡之类的商品都号称含有“纳米粒子”。     

特种纳米涂料

一、主要技术内容 "特种纳米涂料"系"九五"科技攻关成果项目. 纳米材料是由表面(界面)结构组元构成的材料,粒径介于原子团簌与常规粉体之间,一般不超过100纳米.一般根据纳米材料的不同需要,控制其粒子的形态就形成了以下三种纳米材料三维尺寸均为纳米量级的为三维纳米材料,如纳米粉体;某二维尺寸为纳米量级的为二维纳米材料,如层状纳米材料;某一维尺寸为纳米量级的为二维纳米材料,如纳米纤维.     

纳米生物机器原理、制备及其应用探索

纳米生物机器是纳米生物技术领域的前沿热点之一,不仅对了解细胞运作规律、构建人工纳米机器有着重要意义,还为智能材料体系,生物传感器的设计、构造等提供理论和技术基础。本项目围绕纳米生物机器的构建及其运动机理这一核心问题,主要针对典型的天然蛋白质机器和人工核酸机器,通过对其结构与操控机制的研究,探索纳米生物机器的构建原理及一般性工作原理,发展纳米生物机器操控的新方法,     

同构实在论与模型认识论——为罗素的结构实在论辩护

在科学实在论和反实在论的长期的反复的哲学争论中,二十世纪初创建的结构实在论(Structur-alrealism)的学说,最近已成为"科学实在论最有辩护力的形式"(〔1〕,p.1),且"近年来重新进入科学哲学的主流"(〔2〕,p.151)。结构实在论被公认的创始人是著名哲学家罗素。他认为客观事物,特别是不可观察的客体的内部性质是不可认识的,但它的结构可以通过同构关系被人们的感性经验和科学模型认识。本文作者对事物的内部性质不可知持一种保留态度,但对他的通过同构关系认识物质世界的结构持一种赞成的态度,并依罗素的主张将这个观点称为同构实在论,从现象世界与客观世界的同构关系,同态对应在科学理论的模型中的作用和通过建模认识世界的模型这三个方面为罗素的同构实在论和由此决定的认识论辩护,并将它改进为同态实在论,以便更好地说明模型的认识论。     

纳米科学与酶

现代生命科学的发展尤其注重极端条件下生物体系的潜力。作为工业生物技术科学的一个分支,现代酶技术广泛探索如何极大限度地使酶在细胞外长期保持活性,并能有效地适应非生态环境的条件。纳米科学的迅速发展为酶的稳定和高效催化转化带来了新的机遇。纳米材料和酶技术结合可制备纳米酶催化剂,其纳米结构不仅能使酶在不同体系长期保持活性稳定,而且能提高水相、有机相、油．水界面的催化效率,并使多酶体系催化反应和辅酶再生成为可能。纳米颗粒的高曲率能降低酶固定化时的变构,纳米颗粒的布朗运动使纳米固定化酶和底物频繁碰撞,大幅度提高催化效率。同样,纳米纤维和纳米孔均能很好地保持酶的活性。用合适的纳米颗粒和纳米纤维修饰酶,可使酶自组装于油-水界面,不仅加速了油-水界面反应,而且使酶在油-水界面保持稳定。纳米孔还使伴随辅酶再生的多酶催化体系成为可能。深入研究纳米结构对酶稳定性的影响规律,从而根据酶的特性设计最佳的纳米结构是今后的挑战。利用多酶催化体系的工业生物技术是一个极具挑战性和前瞻性的发展方向。同时,微反应器的设计使纳米酶的回收利用成为可能,将带来更大的工业应用优势。     

A validation study of a variable weighting algorithm for cluster analysis

De Soete (1986, 1988) proposed a variable weighting procedure when Euclidean distance is used as the dissimilarity measure with an ultrametric hierarchical clustering method. The algorithm produces weighted distances which approximate ultrametric distances as closely as possible in a least squares sense. The present simulation study examined the effectiveness of the De Soete procedure for an applications problem for which it was not originally intended. That is, to determine whether or not the algorithm can be used to reduce the influence of variables which are irrelevant to the clustering present in the data. The simulation study examined the ability of the procedure to recover a variety of known underlying cluster structures. The results indicate that the algorithm is effective in identifying extraneous variables which do not contribute information about the true cluster structure. Weights near 0.0 were typically assigned to such extraneous variables. Furthermore, the variable weighting procedure was not adversely effected by the presence of other forms of error in the data. In general, it is recommended that the variable weighting procedure be used for applied analyses when Euclidean distance is employed with ultrametric hierarchical clustering methods.     

On Gene’s Action and Reciprocal Causation

Advancing the reductionist conviction that biology must be in agreement with the assumptions of reductive physicalism (the upward hierarchy of causal powers, the upward fixing of facts concerning biological levels) A. Rosenberg argues that downward causation is ontologically incoherent and that it comes into play only when we are ignorant of the details of biological phenomena. Moreover, in his view, a careful look at relevant details of biological explanations will reveal the basic molecular level that characterizes biological systems, defined by wholly physical properties, e.g., geometrical structures of molecular aggregates (cells). In response, we argue that contrary to his expectations one cannot infer reductionist assumptions even from detailed biological explanations that invoke the molecular level, as interlevel causal reciprocity is essential to these explanations. Recent very detailed explanations that concern the structure and function of chromatin—the intricacies of supposedly basic molecular level—demonstrate this. They show that what seem to be basic physical parameters extend into a more general biological context, thus rendering elusive the concepts of the basic level and causal hierarchy postulated by the reductionists. In fact, relevant phenomena are defined across levels by entangled, extended parameters. Nor can the biological context be explained away by basic physical parameters defining molecular level shaped by evolution as a physical process. Reductionists claim otherwise only because they overlook the evolutionary significance of initial conditions best defined in terms of extended biological parameters. Perhaps the reductionist assumptions (as well as assumptions that postulate any particular levels as causally fundamental) cannot be inferred from biological explanations because biology aims at manipulating organisms rather than producing explanations that meet the coherence requirements of general ontological models. Or possibly the assumptions of an ontology not based on the concept of causal powers stratified across levels can be inferred from biological explanations. The incoherence of downward causation is inevitable, given reductionist assumptions, but an ontological alternative might avoid this. We outline desiderata for the treatment of levels and properties that realize interlevel causation in such an ontology.     

Seismites(地震岩)等术语的概念与名称

seismites,按其字面意思理应翻译成地震岩,即与地震有成因联系或受发震断裂改造、变形的岩石。按发震时地质材料的固结程度与力学性质,地震岩可分为震积岩(地震时尚未固结成岩的含水沙土层,即软沉积物)和脆性断层岩(地震时已经固结成岩的沉积岩、岩浆岩和变质岩)。脆性断层岩包括断层角砾岩、碎裂岩、超碎裂岩、假熔岩和断层泥等。发育由沙土液化形成的软沉积物变形构造的沉积岩,统称为“沙土液化岩”(liquefactites),但是长期以来一直被误译为seismites。大量的研究表明,并不是所有的沙土液化和软沉积物变形都是由地震造成的,也并不是所有地震都能导致沙土液化。只有那些所在区域存在重要发震断层、真正由地震引起的区域性的沙土液化造成的软沉积物发育变形构造的岩层才能称之为震积岩(seismic liquefactites)。震积岩不应再翻译成seismites。零星出现的软沉积物变形构造与沙土液化构造(例如:砂涌丘)不足以作为古地震的证据。     

Fast random generation of binary,t-ary and other types of trees

Trees, and particularly binary trees, appear frequently in the classification literature. When studying the properties of the procedures that fit trees to sets of data, direct analysis can be too difficult, and Monte Carlo simulations may be necessary, requiring the implementation of algorithms for the generation of certain families of trees at random. In the present paper we use the properties of Prufer's enumeration of the set of completely labeled trees to obtain algorithms for the generation of completely labeled, as well as terminally labeled t-ary (and in particular binary) trees at random, i.e., with uniform distribution. Actually, these algorithms are general in that they can be used to generate random trees from any family that can be characterized in terms of the node degrees. The algorithms presented here are as fast as (in the case of terminally labeled trees) or faster than (in the case of completely labeled trees) any other existing procedure, and the memory requirements are minimal. Another advantage over existing algorithms is that there is no need to store pre-calculated tables.     

层状金属材料断裂行为的尺度与界面/晶界效应研究

本研究采用三点弯曲实验方法系统地研究了具有不同尺度组元层和界面结构搭配的Cu/Au和Cu/Cr层状材料的断裂行为及其尺度与界面/晶界效应。研究发现,组元性质、尺度和界面/晶界结构是影响金属多层材料变形和断裂行为的主要因素。对于具有"透明"界面的Cu/Au多层材料,其变形和断裂行为表现出显著的尺度效应,而具有"模糊"界面的Cu/Cr多层材料的塑性相对较差,其变形和断裂行为没有明显的尺度效应。基于理论分析,提出了高强高韧层状金属材料的多尺度层状结构设计思路。     

Development (and Evolution) of the Universe

I distinguish Nature from the World. I also distinguish development from evolution. Development is progressive change and can be modeled as part of Nature, using a specification hierarchy. I have proposed a ‘canonical developmental trajectory’ of dissipative structures with the stages defined thermodynamically and informationally. I consider some thermodynamic aspects of the Big Bang, leading to a proposal for reviving final cause. This model imposes a ‘hylozooic’ kind of interpretation upon Nature, as all emergent features at higher levels would have been vaguely and episodically present primitively in the lower integrative levels, and were stabilized materially with the developmental emergence of new levels. The specification hierarchy’s form is that of a tree, with its trunk in its lowest level, and so this hierarchy is appropriate for modeling an expanding system like the Universe. It is consistent with this model of differentiation during Big Bang development to view emerging branch tips as having been entrained by multiple finalities because of the top-down integration of the various levels of organization by the higher levels.     

Mathematical,Philosophical and Semantic Considerations on Infinity (I): General Concepts

In the Reality we know, we cannot say if something is infinite whether we are doing Physics, Biology, Sociology or Economics. This means we have to be careful using this concept. Infinite structures do not exist in the physical world as far as we know. So what do mathematicians mean when they assert the existence of ω (the mathematical symbol for the set of all integers)? There is no universally accepted philosophy of mathematics but the most common belief is that mathematics touches on another worldly absolute truth. Many mathematicians believe that mathematics involves a special perception of an idealized world of absolute truth. This comes in part from the recognition that our knowledge of the physical world is imperfect and falls short of what we can apprehend with mathematical thinking. The objective of this paper is to present an epistemological rather than an historical vision of the mathematical concept of infinity that examines the dialectic between the actual and potential infinity.     

Dendrimer的中文名亟需规范统一

树枝状化合物dendrimer因其独特的完美结构以及由此决定的独特性能,在最近20多年里获得了突飞猛进的发展。但关于dendrimer中文名的使用却非常混乱,在中国大陆至少有36种不同的中文名。这种状况严重地阻碍了这门新兴边缘学科在中国的交流与发展,亟需规范统一。综合考虑dendrimer今后在中国的长远发展及名词的实用性等因素,建议将“树状物”作为dendrimer的中文定名。