Strong Strain Hardening in Nanocrystalline Nickel

Low strain hardening has hitherto been considered an intrinsic behavior for most nanocrystalline (NC) metals, due to their perceived inability to accumulate dislocations. In this Letter, we show strong strain hardening in NC nickel with a grain size of 20 nm under large plastic strains. Contrary to common belief, we have observed significant dislocation accumulation in the grain interior. This is enabled primarily by Lomer-Cottrell locks, which pin the lock-forming dislocations and obstruct islocation. motion. These observations may help with developing strong and ductile NC metals and alloys.

猪囊尾蚴铜/锌超氧化物歧化酶(Cu/ZnSOD)基因的克隆和表达

目的克隆猪囊尾蚴胞质含铜/锌的超氧化物歧化酶基因(Cu/ZnSOD),并比较其与其它寄生蠕虫相应基因结构的相似性。方法通过获取其它生物Cu/ZnSOD基因的保守区域,设计保守引物,用于扩增该寄生虫的Cu/ZnSOD基因。结果Cu/ZnSOD基因编码一15.6kDa的蛋白,该蛋白的推导序列中含有这类酶的活性和二级结构所需要的所有保守的氨基酸残基,并且与其它寄生虫的相应序列有高达70.6%的相似度。抑制剂研究试验表明所克隆的SOD属于Cu/ZnSOD,该蛋白在大肠杆菌中得以成功表达,表达产物具有SOD活性。免

Identification and characterization of a cathepsin L-like cysteine protease from Taenia solium metacestode

Taenia solium metacestode, a larval pork tapeworm, is a causative agent of neurocysticercosis, one of the most common parasitic diseases in the human central nervous system. In this study, we identified a cDNA encoding for a cathepsin L-like cysteine protease from the T solium metacestode (TsCL-1) and characterized the biochemical properties of the recombinant enzyme. The cloned cDNA of 1216 bp encoded 339 amino acids with an approximate molecular weight of 37.6 kDa which containing a typical signal peptide sequence (17 amino acids), a pro-domain (106 amino acids), and a mature domain (216 amino acids). Sequence alignments of TsCL-1 showed low sequence similarity of 27.3-44.6 to cathepsin L-like cysteine proteases from other helminth parasites, but the similarity was increased to 35.9-55.0 when compared to mature domains. The bacterially expressed recombinant protein (rTsCL-1) did not show enzyme activity; however, the rTsCL-1 expressed in Pichia pastoris showed typical biochemical characteristics of cysteine proteases. It degraded human immunoglobulin G (IgG) and bovine serum albumin (BSA), but not collagen. Western blot analysis of the rTsCL-1 showed antigenicity against the sera from patients with cysticercosis, sparganosis or fascioliasis, but weak or no antigenicity against the sera from patients with paragonimiasis or clonorchiasis. (c) 2006 Published by Elsevier B.V.

End-pumped continuous-wave passively modelocked Nd : YVO4 laser with low pump power

A simple cw mode-locked solid-state laser, which is end-pumped by a low-power laser diode, was demonstrated by optimizing the laser-mode size inside the gain medium. The optimum ratio between mode and pump spot sizes inside the laser crystal was estimated for a cw mode-locked laser, taking into account the input pump power. Calculation and experiment have shown that the optimum ratio was about 3 when the pump power is 2 W, which is different from the value regularly used in passively mode-locked solid-state lasers. This conclusion is also helpful in increasing the efficiency of high-power ultrashort lasers. (C) 2006 Society of Photo-Optical Instrumentation Engineers.

大豆超氧岐化酶和品质因素相关性研究

本文进行了大豆种子超氧岐化酶和大豆品质因素（脂肪酸）之间的相关性研究。在这一研究中，我们使用了三种方法：1、HPLC分离测定脂肪酸的组成。2、用聚丙烯酰胺凝胶电泳研究同功酶。3、建立了自旋捕捉方法分析超氧岐化酶的活性。我们对二十四种大豆进行了研究：虎林野生大豆、公主岭野生大豆、秣食豆、黑豆、金元1号、满仓金、小金黄、东农4号、大白眉、早丰1号、十胜长叶、阿姆索、九农9号、黑河3号、绥农4号、黑农26号、吉林3号、合丰23号、哈76-6296、辽宁3号、吉林20、铁丰18、长农4号和EVANS、结果表明大豆种子SOD的比活力和其油脂含量呈极显著负相关；和亚麻酸含量呈极显著正相关；和油酸含量呈极显著负相关；和棕榈酸含量呈显著正相关；和亚油酸含量基本无关；和不饱和脂肪酸和为负相关。其直线回归方程分别为：Yoil = 27.72270-193.04800X比活力 Y18:3 = 3.64289 + 86.69367X比活力 Y18:1 = 31.42366 - 206.61395X比活力 Y16:0 = 9.03986 + 73.46336X比活力 只考虑栽培大豆，它们均未达到5％的显著水平。同功酶的研究结果表明，同功酶可分三个谱带区：A、B和C区，A区为MN-SOO、B、C区均为Cu、Zn-SOD。其中：虎林野生大豆、公主岭野生大豆，秣食豆、黑豆均有两条Mn-SOD同功酶谱带，其余二十个品种栽培大豆均有一条。吉林3号、吉林20的B区只有一条Cu、Zn-SOD同功酶谱带，其余二十二种大豆均有三条。C区都为三条Cu、Zn-SOD同功酶谱带。A、B和C区的百分量和大豆含油量、脂肪酸进行相关分析。结果表明，只有栽培大豆的A区和亚麻含量为显著负相关，其它均没达到5％的显著水平。其直线回归方程为：YA = 43.3277 - 2.5481 X18:3对用HPLC分离脂肪酸的文献方法进行了改进，由文献的1小时改进到每个样品十八分钟。并对二十四种大豆的脂肪酸组成进行了分离测定，结果发现，野生大豆、半栽培大豆和黑豆的亚麻酸含量高于栽培大豆。对光照核黄素体系，DMPO捕捉O_2:的机理进行了探讨。通过SOD抑制O_2~-的DMPO捕捉加合物DMPO－OOH的生成，建立了用自旋捕捉方法分析SOD的活性，并对二十四种大豆种子SOD的活性进行了分析，结果发现，野生大豆，半栽培大豆和黑豆的SOD比活力偏高。

Morphology and Molecular Phylogeny of Trimyema koreanum n. sp., a Ciliate from the Hypersaline Water of a Solar Saltern

A new ciliate, Trimyema koreanum n. sp., isolated from hypersaline water (salinity of 293 parts per thousand) from a solar saltern in Korea, was investigated using live observation, protargol impregnation, and gene sequencing. Trimyema koreanum is about 30 x 13 mu m in vivo, has usually 23 longitudinal ciliary rows forming two distinct ciliary girdles visible both in vivo and in protargol impregnation. A third indistinct ciliary girdle as well as a girdle of mucocysts is distinguishable only in impregnated cells. We suggest T. koreanum as a new species, differing from the most similar species, T. marinum, by the presence of two distinct ciliary girdles (T. marinum usually has six ciliary girdles clearly visible in living cells and three anterior spirals that encircle the cell completely). Although the number of known 18S rRNA sequences in the genus Trimyema was limited, the Trimyema group including T. koreanum forms a strong clade. The phylogenetic position confirms that the isolate belongs to the genus Trimyema and is different from previously sequenced species. Trimyema koreanum is able to consume both prokaryotes and small eukaryotes (specifically, the alga Dunaliella sp.).

Preparation of Dendritic Copper Nanostructures and Their Characterization for Electroreduction

Dendritic copper nanostructures of different morphologies were synthesized by a surfactant-free electrochemical method. Single crystal nature of the nanostructures was revealed from their X-ray diffraction and electron diffraction patterns. Mechanism of dendrite formation was discussed from thermodynamic aspects using the concept of supersaturation. Supersaturation of the copper metal reduced on the surface of the electrode was the crucial factor for the generation of different morphologies. Effects of applied potential, temperature, and the solution concentration on the supersaturation were studied. The NO3- and H2O2 electroreduction ability of the dendritic materials was tested. Use of copper dendrite-modified electrode as NO3- sensor was demonstrated.

Continuous configuration time-dependent self-consistent field method for polyatomic quantum dynamical problems

A new continuous configuration time-dependent self-consistent field method has been developed to study polyatomic dynamical problems by using the discrete variable representation for the reaction system, and applied to a reaction system coupled to a bath. The method is very efficient because the equations involved are as simple as those in the traditional single configuration approach, and can account for the correlations between the reaction system and bath modes rather well. (C) American Institute of Physics.