987 resultados para 386


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四须ba属是一个“大口袋”类群。中国的四须ba实际上分属于至少4个不同的属。通过与Rainboth的分类系统比对之后,对中国四须ba属鱼类的分类系统重新进行了以下的修订:(1)保山四须ba、软鳍四须ba和异口四须ba归入新光唇鱼属;(2)小四须ba归入盘齿ba属;(3)分布于云南的高体四须ba实为大鳞四须ba,大鳞四须ba应归入高须鱼属;(4)其余四须ba属鱼类,抚仙四须ba、常氏四须ba、太平四须#[183]ba、云南四须ba、颌突四须ba(=洱海四须ba)、鲂形四须ba、棱四须ba、后鳍四须ba和油四须ba均归入吻孔ba属。

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Leber hereditary optic neuropathy (LHON) was the first disease to be linked to the presence of a mitochondrial DNA (mtDNA) mutation. Nowadays over 95% of LHON cases are known to be caused by one of three primary mutations (m.11778G>A, m.14484T>C, and m.34

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p53蛋白质核心区249位点精氨酸被其他残基替换后能引起p53蛋白质核心区L2、L3结构域间的密切联系趋于松散,正常的空间构象发生改变并使整个核心区结构稳定性受到破坏。

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When a thin rectangular plate is restrained on the two long edges and free on the remaining edges, the equivalent stiffness of the restraining joints can be identified by the order of the natural frequencies obtained using the free response of the plate at a single location. This work presents a method to identify the equivalent stiffness of the restraining joints, being represented as simply supporting the plate but elastically restraining it in rotation. An integral transform is used to map the autospectrum of the free response from the frequency domain to the stiffness domain in order to identify the equivalent torsional stiffness of the restrained edges of the plate and also the order of natural frequencies. The kernel of the integral transform is built interpolating data from a finite element model of the plate. The method introduced in this paper can also be applied to plates or shells with different shapes and boundary conditions. © 2011 Elsevier Ltd. All rights reserved.

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有关水生植物净化污水的研究已有广泛报道,但现有成果多来源于静态的室内研究,所用植物多为生活型接近的物种。为了比较不同生活型植物对河道污水的原位净化效果差异,构建了由水芹菜(Oenanthe javanica)、马尾草(Equisetum flu-viatile)、伊乐藻(Elodea Canadensis Michx.)和狐尾藻(Myriophyllum verticillatum L.)等4种不同生活型水生植物组成的水生植物塘系统,研究塘中不同植物对滇池入湖河道污水中氮、磷等指标去除效能的差异。结果表明

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采用0.1,1.0,10.0μg/mL的微囊藻毒素-RR(MC-RR)处理烟草BY-2悬浮细胞,测定了细胞活力、细胞内蛋白质含量、可溶性糖含量、硝态氮含量及总磷含量,并且检测了酸性磷酸酶(ACP)的活力变化情况.结果表明,中、高浓度毒素处理细胞2d后,细胞活力及蛋白质含量与对照相比均显著下降.高浓度MC-RR处理降低了胞内可溶性糖的含量,暴露2d后仅为对照的45.57%;低浓度MC-RR处理在后期增加了胞内可溶性糖含量.高浓度毒素处理细胞4d后,细胞内硝态氮含量显著低于对照;中、低浓度毒素处理细胞7d后降

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描述了采自长白山永青电站的蓝藻门新植物灰白伪枝藻(Scytonema cineraceumC.L.Zhou et Xiao,sp.nov.),其原植体丛生,垫状,近半球形,灰褐色。蓝藻门新植物岩生蓝柄藻(Cy-anostylon rupestrisL.H.L櫣et Xiao,sp.nov.),采自吉林省集安市五女峰,植物团块为较柔软的胶质小皮壳状堆积体,棕黄色或棕红色。

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目的了解微囊藻毒素(MC)LR对L-02细胞的毒性机制。方法以L-02细胞为材料,用不同浓度的MCLR处理该细胞,观察了细胞增殖能力、细胞形态改变、乳酸脱氢酶(LDH)泄漏、细胞凋亡率及凋亡相关基因等一系列指标的变化。结果 MTT细胞增殖实验可知,MCLR在24 h内对L-02细胞有轻微的抑制作用,随后却促进细胞增殖。48 h处理对 LDH泄漏没有显著影响,延时处理导致LDH泄漏发生,且MCLR浓度越高,LDH泄漏越严重,此结果显示发生了细胞氧化损伤。光镜下50μg/ml的毒素浓度在60 h处理后可造成明

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1993年作者对河南信阳市南湾水库网箱养殖鲤鱼肠道单极虫病进行了系统研究。该地区发病率高达 90 %以上 ,发病鲤鱼肠壁上寄生了大量单极虫孢囊 ,破坏肠道组织 ,吸收鱼体营养 ,病鱼失去光泽 ,体色呈暗黑色 ,肠管呈紫红色 ,充满脓血粘液 ,大型孢囊集中在中、后肠 ,孢囊形态大多为椭球形 ,最大个体为 4 .5× 2 .5cm ,肠管膨大一倍以上 ,肠壁变薄 ,肠道完全被堵塞 ,停止进食而死亡。经比较研究 ,该病原体被定为信阳单极虫新种 (Thelohanellusxinyangensissp .nov