Hierarchical Self‐Assembly of Peptide‐Coated Carbon Nanotubes

Numerous applications, from molecular electronics to super‐strong composites, have been suggested for carbon nanotubes. Despite this promise, difficulty in assembling raw carbon nanotubes into functional structures is a deterrent for applications. In contrast, biological materials have evolved to self‐assemble, and the lessons of their self‐assembly can be applied to synthetic materials such as carbon nanotubes. Here we show that single‐walled carbon nanotubes, coated with a designed amphiphilic peptide, can be assembled into ordered hierarchical structures. This novel methodology offers a new route for controlling the physical properties of nanotube systems at all length scales from the nano‐ to the macroscale. Moreover, this technique is not limited to assembling carbon nanotubes, and could be modified to serve as a general procedure for controllably assembling other nanostructures into functional materials.     

装配式贝雷桁架门机设计

本文就装配式贝雷桁架门机的设计要点作了简要的介绍,并对其拼装的技术质量提出要求。     

国内外电雷管电引火元件现状及改进思路

文章分析了目前国内外电引火元件的现状，列举了国外著名火炸药公司典型的几种电引火元件结构及电火参数，提出了改进我国电引火元件的技术构思。     

循环流液相等电聚焦方法及应用研究

利用循环流液相等电聚焦技术，对Ｈｂ、Ｃｙｔ．Ｃ和ＢＳＡ混合物进行分离，对ＲＮａｓｅＡ粗制品进行精制。该方法上样量大，活性回收好。对聚焦过程中扩散、对流和电渗的影响进行了讨论。     

乳腺癌中着丝粒蛋白CenpG的差异表达

用间接免疫荧光（IIF）验证了着丝粒蛋白CenpG的一种抗血清；通过对31例乳腺癌组织块及每一例病人的癌旁正常（非癌性）组织块蛋白提取物进行免疫印迹（Western blot）分析，发现多数情况下（71%）癌组织中着丝粒蛋白CenpG(95kD)过表达；在两例乳腺癌组织中还发现了一种能被CenpG抗血清识别的43kD蛋白质成分。结果表明，新近发现和命名的CenpG（或者还有其他相关成分）的差异表达可能与细胞恶性增殖有关。     

An analysis of contemporary printed wiring board manufacturing environment in the USA

This article presents a comparative analysis of contemporary printed wiring assembly (PWA) batch manufacturing systems employing surface mount technology (SMT), This analysis is accomplished by reviewing a typical case study of PWA manufacturing system in the USA. A previously developed model is then applied to the system to predict the cost and performance in the production of typical PWA designs. Various modifications to the system are then proposed and evaluated. From the case study, conclusions concerning optimum manufacturing system configuration for this industry can be drawn and are presented.     

The effects of induction conditions on production of a soluble antitumor sFv in Escherichia coli

CC49 is a second generation monoclonal antibody(mAb) with highaffinity to a pancarcinoma antigen, TAG-72. A single-chain Fv(sFv)ofCC49 may have a role in managing human carcinomas. Most reportedsFvs have been expressed as insoluble products that must besolubilized and renatured. Soluble sFv expression is advantageousas activity can be assayed directly from the periplasmic fraction.Also, gene-level immunoconjugates may not be amenable to refoldingprotocols. Using a vector that carries the tac promoter andomp A signal, we have examined the effects of four variableson the expression and accumulation of soluble CC49 sFv: (i)linker sequence joining VL and VH, (ii) isopropylthio-ß-D-galactosideconcentration for induction, (iii) temprature, and (iv) theaddition of nonmetabolizable sugars to the medium. We have beenable to demonstrate, using rapidly prepared periplasmic extracts,that the yield of soluble sFv improves by the addition of 0.4Msucrose to the medium and by inducing expression with a verylow concentration of IPTG (0.02–0.03 mM). Under theseinduction conditions periplasmic extracts demonstrate increasedexpression of the sFv, as shown by the larger amount of a 27kDa band on SDS-polyacrylamide gel, and an increased abilityto inhibit binding of the mAb CC49 to immobilized tumor extracts.     

Automating the identification and analysis of protein {beta}-barrels

ßBarrels are widespread and well-studied featuresof a great many protein structures. In this paper an unsuper-visedmethod for the detection of P-barrels is developed based ontechniques from graph theory. The hydrogen bonded connectivityof ß-sheets is derived using standard pattern recognitiontechniques and expressed as a graph. Barrels correspond to topologicalrings in these connectivity graphs and can thus be identifiedusing ring perception algorithms. Following from this, the characteristictopological structure of a barrel can be expressed using a novelform of reduced nomenclature that counts sequence separationsbetween successive members of the ring set These techniquesare tested by applying them to the detection of barrels in anon-redundant subset of the Brookhaven database. Results indicatethat topological rings do seem to correspond uniquely to ß-barrelsand that the technique, as implemented, finds the majority ofbarrels present in the dataset.     

吲哚美辛对荷瘤小鼠抗肿瘤作用机制的实验研究

用微观放射自显影技术及免疫组化法探讨了非甾体类抗炎药吲哚美辛(IN)对Lewis肺癌的生长抑制作用机制。结果显示:与对照组相比,实验组IN的抑瘤率为55.05%;IN可显著下调Bcl-2蛋白的表达(t=6.154,P<0.001),对Bax蛋白的表达没有明显影响(t=2.101,P>0.05)。放射自显影结果显示,在肿瘤细胞的细胞膜、细胞浆及细胞核中均有黑色银颗粒分布,且在用药后12 h时肿瘤组织中的平均银颗粒数高于4、7、243、6 h时。以上结果表明,IN可抑制Lewis肺癌的生长,其机制与下调抗凋亡蛋白Bcl-2的表达及降低Bcl-2/Bax的比值有关;IN可进入到肿瘤细胞内发挥抗肿瘤作用。