在云母晶面上应用“自下而上”和“自上而下”两种途径制造胶原蛋白纳米线阵列

以云母晶体的(001)晶面为基质,以天然Ⅰ型鼠尾胶原蛋白单体溶液为原料,分别考察了蛋白单体受基质规导进行"自下而上"的自组装过程,以及原子力显微镜探针对吸附在基质表面的蛋白膜层进行"自上而下"加工过程:(1)两种制备途径均能加工出结构精确可控的胶原蛋白纳米线阵列;(2)"自下而上"制备途径利用了蛋白单体和基质晶体在界面上互相识别并规范的"反相生物矿化"原理;(3)"自上而下"的加工利用了原子力显微镜接触模式下探针的"分子扫帚"机理。     

The comparison between 2DE-MS and bottom-up LC-MS demands high-end techniques for both technologies

In contrast to bottom-up LC-MS only 2DE-MS can separate and detect a huge number of human protein species. Kwiatkowski et al. (in this issue) established parameters to estimate the amount of protein speciation for each human protein. Proteins identified in 2DE-MS approaches showed more protein speciation than in bottom-up LC-MS. The authors state that protein speciation is likely to increase the chance of proteins to be determined in 2-DE/MS, though admitting that low-sensitivity 2DE-MS methods were used in this study. In agreement with Kwiatkowski et al., we are convinced that the difference between 2DE-MS and bottom-up LC-MS will disappear, if high-resolution 2DE is combined with identification by a high-sensitivity LC-Orbitrap-MS. Meta-analysis of proteomic data is surely a promising tool, though the technological progress in 2DE and MS has to reach a plateau to enable useful comparisons.     

Peptide and protein characterization by high-rate electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry

The analytical utility of the electron capture dissociation (ECD) technique, developed by McLafferty and co-workers, has substantially improved peptide and protein characterization using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The limitations of the first ECD implementations on commercial instruments were eliminated by the employment of low-energy electron-injection systems based on indirectly heated dispenser cathodes. In particular, the ECD rate and reliability were greatly increased, enabling the combination of ECD/FTICR-MS with on-line liquid separation techniques. Further technique development allowed the combination of two rapid fragmentation techniques, high-rate ECD and infrared multiphoton dissociation (IRMPD), in a single experimental configuration. Simultaneous and consecutive irradiations of trapped ions with electrons and photons extended the possibilities for ion activation/dissociation and led to improved peptide and protein characterization. The application of high-rate ECD/FTICR-MS has demonstrated its power and unique capabilities in top-down sequencing of peptides and proteins, including characterization of post-translational modifications, improved sequencing of peptides with multiple disulfide bridges and secondary fragmentation (w-ion formation). Analysis of peptide mixtures has been accomplished using high-rate ECD in bottom-up mass spectrometry based on mixture separation by liquid chromatography and capillary electrophoresis. This paper summarizes the current impact of high-rate ECD/FTICR-MS for top-down and bottom-up mass spectrometry of peptides and proteins.     

The applicability matrix of a syntax-directed parsing processor

Some bottom-up syntax-directed parsing processors use a rectangular Boolean matrix called an applicability matrix to determine which rules might be used in the syntax analysis of an input string of terminal (basic) characters of a given language. By constructing a graph derived from the rules of a language specified in Backus Normal Form, and imposing a partial order on the vertices of this graph, it is shown in this paper that the applicability matrix may be partitioned into 2 submatrices, one of which is rectangular, and the other uppertriangular.     

Energy and Climate Policy Analysis with the Hybrid Bottom-Up Computable General Equilibrium Model SCREEN: The Case of the Swiss CO2 Act

This paper shows how bottom-up activity analyses within a dynamic computable general equilibrium framework can be undertaken for the longer-term analysis of energy and climate policies using the model SCREEN [25]. In particular we demonstrate for the case of Switzerland how the impact of policy measures to reduce the carbon intensity of the energy sector can be assessed with such a model for various socio-economic and environmental dimensions (e.g., C0₂ emissions, GDP, employment, foreign exchange rate). The results can provide valuable insights for the appropriate design of energy or climate policies that allow for the targeted fostering of a more sustainable energy development.     

超级化学镀铜填充微道沟的研究

超级化学铜填充技术不仅可以应用于半导体超大集成电路铜互连线, 而且可以应用于三维封装. 研究了不同浓
度、不同分子量的PEG 对以甲醛为还原剂的化学镀铜溶液中铜的沉积速率的影响. 随着添加剂PEG 浓度和分子量的
增大, 化学铜的沉积速率明显降低. 电化学研究结果表明PEG 通过抑制甲醛的氧化反应降低化学铜的沉积速率, PEG
分子量越大, 对化学铜的抑制作用越强. 利用PEG-6000 对化学铜的抑制作用和在溶液中低的扩散系数, 采用添加
PEG-6000 的化学镀铜溶液, 成功地实现了宽度在0.2 μm 以下微道沟的超级化学填充. 就PEG 的分子量、微道沟的深
径比等因素对超级化学铜填充的影响也做了研究.     

Bottom-Up Synthesis,Dispersion and Properties of Rectangular-Shaped Graphene Quantum Dots

Carbon nanomaterials have attracted the attention of the scientific community for more than 30 years now; first with fullerene, then with nanotubes and now with graphene and graphene related materials. Graphene quantum dots (GQDs) are nanoparticles of graphene that can be synthesized following two approaches, namely top-down and bottom-up methods. The top-down synthesis used harsh chemical and/or physical treatments of macroscopic graphitic materials to obtain nanoparticles, while the second is based on organic chemistry through the synthesis of polycyclic aromatic hydrocarbons exhibiting various sizes and shapes that are perfectly controlled. The main drawback of this approach is related to the low solubility of carbon materials that prevents the synthesis of nanoparticles containing more than few hundreds of sp² carbon atoms. Here we report on the synthesis of a family of rectangular-shaped graphene quantum dots containing up to 162 sp² carbon atoms. These graphene quantum dots are not functionalized on their periphery in order to keep the maximum similarity with nanoparticles of pure graphene. We chose water with sodium deoxycholate surfactant to study their dispersion and their optical properties (absorption, photoluminescence and photoluminescence excitation). The electronic structure of the particles and of their aggregates are studied using Tight-Binding (TB). We observe that the larger particles ( GQD 3 and GQD 4 ) present a slightly better dispensability than the smaller ones, probably because the larger GQDs can accommodate more surfactant molecules on each side, which helps to stabilize their dispersion in water.     

有机多孔催化研究进展

有机多孔材料POPs (Porous Organic Polymers)成为近年来的研究前沿之一. 有机多孔材料包括非晶型(如CMP, HCP, PIM等)和晶型(比如COFs等)有机多孔材料两类, 它们具有优异的孔性质、较大的比表面积、稳定性好、重量轻以及易于功能化等诸多优点, 被广泛应用于气体存储分离、传感、有机光电和多相催化等重要领域. 这里对有机多孔材料在多相催化领域中的应用做一综述. 目前, 有机多孔催化领域的研究工作主要有三类: 一类是通过“自下而上”策略将金属-配体类催化剂嵌入有机多孔骨架来构建多相催化剂; 另一类是将有机多孔材料作为载体, 通过后修饰方式负载金属纳米颗粒构建多相催化剂; 最后一类是通过“自下而上”策略将不含金属的有机小分子催化剂嵌入材料骨架来构建多孔有机催化剂. 受益于其结构的优越性, 有机多孔材料在多相催化中表现出优异的催化性能. 借鉴于均相催化的发展, 具有催化活性的有机多孔材料在多相催化领域中的应用也将会有更大的发展空间.     

Artificial Cytoskeleton Assembly for Synthetic Cell Motility

Imitation of cellular processes in cell-like compartments is a current research focus in synthetic biology. Here, a method is introduced for assembling an artificial cytoskeleton in a synthetic cell model system based on a poly(N-isopropyl acrylamide) (PNIPAM) composite material. Toward this end, a PNIPAM-based composite material inside water-in-oil droplets that are stabilized with PNIPAM-functionalized and commercial fluorosurfactants is introduced. The temperature-mediated contraction/release behavior of the PNIPAM-based cytoskeleton is investigated. The reversibility of the PNIPAM transition is further examined in bulk and in droplets and it could be shown that hydrogel induced deformation could be used to controllably manipulate droplet-based synthetic cell motility upon temperature changes. It is envisioned that a combination of the presented artificial cytoskeleton with naturally occurring components might expand the bandwidth of the bottom-up synthetic biology.