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1.
The Ni samples were electroformed from additive-free(AF) and saccharin-containing(SC) sulfamate solutions, respectively. In situ backscattered electron(BSE) imaging, electron backscatter diffraction(EBSD), and electron-probe microanalysis(EPMA) were used to investigate the effect of annealing on the deformation behaviors of the AF and SC samples. The results indicate that columnar grains of the as-deposited AF sample had an approximated average width of 3 μm and an approximated aspect ratio of 8. The average width of columnar grains of the as-deposited SC sample was reduced to approximately 400 nm by the addition of saccharin to the electrolyte. A few very-large grains distributed in the matrix of the SC sample after annealing. No direct evidence indicated that S segregated at the grain boundaries before or after annealing. The average value of the total elongations of the SC samples decreased from 16% to 6% after annealing, whereas that of the AF samples increased from 18% to 50%. The dislocation recovery in grain-boundary areas of the annealed AF sample was reduced, which contributed to the appearance of microvoids at the triple junctions. The incompatibility deformation between very-large grains and fine grains contributed to the brittle fracture behavior of the annealed SC Ni.  相似文献   
2.
Cpdm (chronic proliferative dermatitis) mice develop chronic dermatitis and an immunodeficiency with increased serum IgM, symptoms that resemble those of patients with X-linked hyper-IgM syndrome and hypohydrotic ectodermal dysplasia (XHM-ED), which is caused by mutations in NEMO (NF-κB essential modulator; also known as IKBKG). Spontaneous null mutations in the Sharpin (SHANK-associated RH domain interacting protein in postsynaptic density) gene are responsible for the cpdm phenotype in mice. SHARPIN shows significant similarity to HOIL-1L (also known as RBCK1), a component of linear ubiquitin chain assembly complex (LUBAC), which induces NF-κB activation through conjugation of linear polyubiquitin chains to NEMO. Here, we identify SHARPIN as an additional component of LUBAC. SHARPIN-containing complexes can linearly ubiquitinate NEMO and activated NF-κB. Thus, we re-define LUBAC as a complex containing SHARPIN, HOIL-1L, and HOIP (also known as RNF31). Deletion of SHARPIN drastically reduced the amount of LUBAC, which resulted in attenuated TNF-α- and CD40-mediated activation of NF-κB in mouse embryonic fibroblasts (MEFs) or B cells from cpdm mice. Considering the pleomorphic phenotype of cpdm mice, these results confirm the predicted role of LUBAC-mediated linear polyubiquitination in NF-κB activation induced by various stimuli, and strongly suggest the involvement of LUBAC-induced NF-κB activation in various disorders.  相似文献   
3.
The genome sequence and structure of rice chromosome 1   总被引:2,自引:0,他引:2  
The rice species Oryza sativa is considered to be a model plant because of its small genome size, extensive genetic map, relative ease of transformation and synteny with other cereal crops. Here we report the essentially complete sequence of chromosome 1, the longest chromosome in the rice genome. We summarize characteristics of the chromosome structure and the biological insight gained from the sequence. The analysis of 43.3 megabases (Mb) of non-overlapping sequence reveals 6,756 protein coding genes, of which 3,161 show homology to proteins of Arabidopsis thaliana, another model plant. About 30% (2,073) of the genes have been functionally categorized. Rice chromosome 1 is (G + C)-rich, especially in its coding regions, and is characterized by several gene families that are dispersed or arranged in tandem repeats. Comparison with a draft sequence indicates the importance of a high-quality finished sequence.  相似文献   
4.
Atomic-beam alignment of inorganic materials for liquid-crystal displays   总被引:1,自引:0,他引:1  
The technique used to align liquid crystals-rubbing the surface of a substrate on which a liquid crystal is subsequently deposited-has been perfected by the multibillion-dollar liquid-crystal display industry. However, it is widely recognized that a non-contact alignment technique would be highly desirable for future generations of large, high-resolution liquid-crystal displays. A number of alternative alignment techniques have been reported, but none of these have so far been implemented in large-scale manufacturing. Here, we report a non-contact alignment process, which uses low-energy ion beams impinging at a glancing angle on amorphous inorganic films, such as diamond-like carbon. Using this approach, we have produced both laptop and desktop displays in pilot-line manufacturing, and found that displays of higher quality and reliability could be made at a lower cost than the rubbing technique. The mechanism of alignment is explained by adopting a random network model of atomic arrangement in the inorganic films. Order is induced by exposure to an ion beam because unfavourably oriented rings of atoms are selectively destroyed. The planes of the remaining rings are predominantly parallel to the direction of the ion beam.  相似文献   
5.
Yu Y  Nakano M  Ikeda T 《Nature》2003,425(6954):145
Polymer solutions and solids that contain light-sensitive molecules can undergo photo-contraction, whereby light energy is converted into mechanical energy. Here we show that a single film of a liquid-crystal network containing an azobenzene chromophore can be repeatedly and precisely bent along any chosen direction by using linearly polarized light. This striking photomechanical effect results from a photoselective volume contraction and may be useful in the development of high-speed actuators for microscale or nanoscale applications, for example in microrobots in medicine or optical microtweezers.  相似文献   
6.
The glomerular filtration barrier in the kidney is formed in part by a specialized intercellular junction known as the slit diaphragm, which connects adjacent actin-based foot processes of kidney epithelial cells (podocytes). Mutations affecting a number of slit diaphragm proteins, including nephrin (encoded by NPHS1), lead to renal disease owing to disruption of the filtration barrier and rearrangement of the actin cytoskeleton, although the molecular basis for this is unclear. Here we show that nephrin selectively binds the Src homology 2 (SH2)/SH3 domain-containing Nck adaptor proteins, which in turn control the podocyte cytoskeleton in vivo. The cytoplasmic tail of nephrin has multiple YDxV sites that form preferred binding motifs for the Nck SH2 domain once phosphorylated by Src-family kinases. We show that this Nck-nephrin interaction is required for nephrin-dependent actin reorganization. Selective deletion of Nck from podocytes of transgenic mice results in defects in the formation of foot processes and in congenital nephrotic syndrome. Together, these findings identify a physiological signalling pathway in which nephrin is linked through phosphotyrosine-based interactions to Nck adaptors, and thus to the underlying actin cytoskeleton in podocytes. Simple and widely expressed SH2/SH3 adaptor proteins can therefore direct the formation of a specialized cellular morphology in vivo.  相似文献   
7.
Methane emissions from wetlands on the Qinghai-Tibet Plateau   总被引:4,自引:0,他引:4  
The areal extent of cold freshwater wetlands on the Qinghai-Tibet Plateau (QTP) is estimated at 0.133 × 106 km2, suggesting a significant methane potential. Methane fluxes from wet alpine meadows, peatlands,Hippuris vulgaris mires and secondary marshes were 43.18, 12.96, −0.28 and 45.90 mg · m−2 · d−1, respectively based on the transect flux studies at the Huashixia Permafrost Station (HPS) from July to August 1996. Average CH4 fluxes in the thaw season were extrapolated at 5.68 g · m−2 according to the areal percentage of wetland areas in the Huashixia region. The CH4 fluxes at four fixed sites, representative of similar ecosystems, ranged from −19.384–347.15 mg · m−2 · d−1, and the average CH4 fluxes varied from 6.54 to 71.97 mg · m−2 · d−1 at each site during the observation period from April to September 1997. The CH4 emissions at each site during the entire thaw season was estimated from 1.21 to 10.65 g · m−2, displaying strong spatial variations. Seasonal variations of CH4 fluxes also were observed at four sites: CH4 outbursts occurred upon the spring thaw in May and June, CH4 fluxes increased afterwards with rising soil temperatures. Episodic fluxes were observed in summer, which influenced the average CH4 fluxes considerably. Annual CH4 emissions from cold wetlands on the QTP were estimated at about 0.7–0.9 Tg based on the distribution of wetlands, representative CH4 fluxes, and number of thaw days. The centers of CH4 releasing were located in the sources of the Yangtze and Yellow rivers, and Zoigê Peatlands.  相似文献   
8.
Haploinsufficiency of NSD1 causes Sotos syndrome   总被引:14,自引:0,他引:14  
We isolated NSD1 from the 5q35 breakpoint in an individual with Sotos syndrome harboring a chromosomal translocation. We identified 1 nonsense, 3 frameshift and 20 submicroscopic deletion mutations of NSD1 among 42 individuals with sporadic cases of Sotos syndrome. The results indicate that haploinsufficiency of NSD1 is the major cause of Sotos syndrome.  相似文献   
9.
The medaka draft genome and insights into vertebrate genome evolution   总被引:3,自引:0,他引:3  
Teleosts comprise more than half of all vertebrate species and have adapted to a variety of marine and freshwater habitats. Their genome evolution and diversification are important subjects for the understanding of vertebrate evolution. Although draft genome sequences of two pufferfishes have been published, analysis of more fish genomes is desirable. Here we report a high-quality draft genome sequence of a small egg-laying freshwater teleost, medaka (Oryzias latipes). Medaka is native to East Asia and an excellent model system for a wide range of biology, including ecotoxicology, carcinogenesis, sex determination and developmental genetics. In the assembled medaka genome (700 megabases), which is less than half of the zebrafish genome, we predicted 20,141 genes, including approximately 2,900 new genes, using 5'-end serial analysis of gene expression tag information. We found single nucleotide polymorphisms (SNPs) at an average rate of 3.42% between the two inbred strains derived from two regional populations; this is the highest SNP rate seen in any vertebrate species. Analyses based on the dense SNP information show a strict genetic separation of 4 million years (Myr) between the two populations, and suggest that differential selective pressures acted on specific gene categories. Four-way comparisons with the human, pufferfish (Tetraodon), zebrafish and medaka genomes revealed that eight major interchromosomal rearrangements took place in a remarkably short period of approximately 50 Myr after the whole-genome duplication event in the teleost ancestor and afterwards, intriguingly, the medaka genome preserved its ancestral karyotype for more than 300 Myr.  相似文献   
10.
通过两个研究考察领悟社会支持和客观社会支持与社交焦虑的关系, 并探索领悟社会支持对社交焦虑个体网络认知行为治疗(ICBT)干预的效果。研究1: 对122名大学生被试进行两个时间点的社会支持与社交焦虑的测量, 结果发现领悟社会支持与社交焦虑相互影响, 领悟社会支持在客观社会支持与社交焦虑之间起中介作用, 中介效应的95%置信区间为[–1.47, –0.09]。研究2: 对比64名不同领悟社会支持水平的被试接受社会支持网络认知行为治疗与自助网络认知行为治疗的疗效, 结果发现社会支持组和自助组的被试在接受干预后社交焦虑得分都有显著下降, 领悟社会支持得分都有显著提高(社会支持组的得分显著高于自助组)。被试的领悟社会支持得分与有无社会支持被试的 ICBT 干预效果存在交互作用, 有支持小组的ICBT对低领悟社会支持个体干预效果更好, 而无支持小组的ICBT对高领悟社会支持个体干预效果更好。研究结果进一步理解并澄清了社会支持在社交焦虑中的作用, 可为未来临床工作的实践与应用提供了依据和方向。  相似文献   
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