中国神农架国家森林公园苔藓中的缓步动物

记述了采自湖北省西部神农架国家森林公园苔藓中的缓步动物12种,包括:日本棘影熊虫Echiniscus japonicus Morikawa,1951;双粒棘影熊虫Echiniscus bigranulatus Richters,1907中国新纪录种;华美假棘影熊虫Pseudechiniscus facettalis Petersen,1951;于猪假棘影熊虫Pseudechiniscus suillus(Ehrenberg,1853);迟缓小斑熊虫Milnesium tardigradum(Doyère,

温度和pH值对嗜水气单胞菌毒力基因表达的影响

为了解培养温度和pH值对嗜水气单胞菌的毒力基因表达以及致病性的影响,利用反转录PCR(RT-PCR)对4种基因的表达进行了研究。研究结果显示嗜水气单胞菌毒力基因的表达受温度和pH值影响,其中溶血素(AHH)、气溶素(AerA)、外膜蛋白(OMP)和粘附素(Aha)毒力基因在15℃、25℃和37℃下均能高效表达,在4℃AHH和AerA两基因也能持续表达,但OMP和Aha两基因的表达停止。在中性或偏酸性的条件下(pH5.0和pH7.0)4种毒力基因都得以表达,在碱性条件下(pH9.0)4种基因中只有AHH得以

荧光原位杂交技术(FISH)及其在环境微生物学中的应用

微生物对整个生态系统具有重要的影响,了解和检测微生物的种类具有十分重要的意义。但是传统的培养方法又不能满足科学研究的需要,荧光原位杂交技术(ＦＩＳＨ)就是近年发展起来的一种快速准确检测微生物的方法。作者较全面地介绍了ＦＩＳＨ技术的优点、微生物的分离和固定方法,以及原位杂交过程,同时对ＦＩＳＨ技术在环境微生物学中的应用及其前景作了展望。

微囊藻毒素对鱼蛋白磷酸酶抑制作用的研究

国家自然科学基金39400024;淡水生态与生物技术国家重点实验室资助

我国对虾暴发性流行病病因初探

我国对虾暴发性流行病病因初探江育林，张奇亚，刘荭，李彦，李正秋（中国科学院水生生物研究所武汉４３００７２）关键词杆状病毒、对虾病毒病、中国对虾、日本对虾ＳＴＵＤＹＯＮＣＡＵＳＥＯＦＩＮＦＥＣＴＩＯＮＳＤＩＳＥＡＥＳＯＦＰＥＮＡＥＩＤＳＨＲＩＭＰＩＮＣ...

Quantum dots and nanowires for optoelectronic device applications

InGaAs quantum dots (QDs) and nanowires have been grown on GaAs by metal-organic chemical vapour deposition on GaAs (100) and (111)B substrates, respectively. InGaAs QD lasers were fabricated and characterised. Results show ground-state lasing at about 1150 nm in devices with lengths greater than 2.5 mm. We also observed a strong influence of nanowire density on nanowire height specific to nanowires with high indium composition. This dependency was attributed to the large difference of diffusion length on (111)B surfaces between In and Ga reaction species, with In being the more mobile species. Selective area epitaxy for applications in quantum-dot optoelectronic device integration is also discussed in this paper. ©2006 IEEE.

复合四倍体异育银鲫产生的细胞学机制

<正> 银鲫是行天然雌核发育生殖的鱼类。以往对其繁殖生物学的研究一般都认为:异源父本的性状不能或仅能少量地在子代群体中得到表达。但桂建芳等(1991)在人工繁育的异育银鲫群体中发现了具有一整套父本染色体组的复合四倍体鱼,其出现率为0.2％左右。此外,Kobayasi

葡萄藻三个品系脂类物质含量的比较研究

<正> 葡萄藻作为一种新的再生性能源的研究,已引起了不少学者的重视。其中较为关键的是对葡萄藻所含脂类物质的研究。过去通常采用重量法及各类色谱法测定植物中的脂类物质。这些方法不但繁琐,而且均需一个较长时间的提取过程。近年来国外采用一种新型染料——尼罗

宜昌鳅鮀仔稚鱼的形态特征

<正> 宜昌鳅(鱼它)系底栖性小型鱼类,在长江宜昌江段的渔获物中时有出现。繁殖期为5—6月,产漂流性卵,膜径在3.1—4.0毫米之间,水温21.2—25℃时,受精卵约经40小时孵出。作者对其仔稚鱼的形态进行了观察。实验材料系长江宜都江段采得的天然受精卵,经室内孵化培养而成的仔稚鱼。选择一尾经乌拉坦(ureathane)麻醉后在解剖镜下测量身体各部比例,记述形态特征,并绘制草图。另选两尾作对照。开始摄食后,以浮游生物喂养,培育至外

Modeling turn-off voltage rise in SOI LIGBT

The behavior of the drain voltage rise of the Lateral IGBT during inductive turn-off is studied in detail. Numerical simulations show that, if compared with the well known vertical IGBT, the Lateral IGBT presents a differences in the on-state stored charge and in the growth of the depleted region that result in a different drain voltage rise. In this paper a complete model for the voltage rise is devised through an accurate calculation of the equivalent output capacitance. The model is in excellent agreement with two-dimensional simulations. Further, the paper shows that previously proposed models, which targeted the vertical IGBT, are not adequate for the description of the turn-off voltage rise in the Lateral IGBT. © Springer Science + Business Media LLC 2006.

Mix design, mechanical properties and impact resistance of UHPFRCCs

The research work focused on the determination of guidelines for the production of an UHPFRCC, and the experimental investigation of the quality and the behaviour of this material in a highly demanding application, such as the impact resistance of structures. Specifically, the aim of this study is to present the results of an extended work on the development of an UHPFRCC and the experimental determination of the mechanical properties of the produced material. Furthermore, the paper will present preliminary experimental results on the impact resistance of Reinforced Concrete and UHPFRCC slab specimens. © 2012 Taylor & Francis Group.

Bioaccumulative characteristics of hexabromocyclododecanes in freshwater species from an electronic waste recycling area in China

Hexabromocyclododecanes (HBCDs) are now emerging ubiquitous contaminants due to their wide usage, persistence and toxicities. To investigate the bioaccumulative characteristics of HBCDs, sediments, Winkle (Littorina littorea), crucian carp (Carassius carassius) and loach (Misgurnus anguillicaudatus) were collected from two streams near an E-waste dismantling site in China. and HBCD exposure test was then conducted on Chinese rare minnow. The concentration of HBCDs was 14 ng g(-1) dry weight in sediments, 186. 377 and 1791 ng g(-1) lipid weight in winkle, crucian carp and loach, respectively. gamma-HBCD was found to be the dominant diastereoisomer in the sediments (63% of total HBCDs). However, alpha-HBCD was selectively accumulated in the biotic samples and contributed to 77%, 63% and 63% of total HBCDs in winkle, crucian carp and loach, respectively. Moreover, an enrichment of (-)-enantiomers of alpha- and gamma-HBCD were found in the winkle. The reverse results were observed in the crucian carp and loach. Similar observations of diastereoisomeric and enantiomeric composition were obtained in Chinese rare minnow with those found in the crucian carp and loach. These results indicate that the freshwater species from the streams are contaminated by HBCDs. alpha-HBCD can be selectively accumulated in organisms and the accumulative characteristics are enantioselective among species. (C) 2009 Elsevier Ltd. All rights reserved.

Reduced swimming abilities in fast-growing transgenic common carp Cyprinus carpio associated with their morphological variations

Critical swimming speeds (U-crit) and morphological characters were compared between the F-4 generation of GH-transgenic common carp Cyprinus carpio and the non-transgenic controls. Transgenic fish displayed a mean absolute U-crit value 22.3% lower than the controls. Principal component analysis identified variations in body shape, with transgenic fish having significantly deeper head, longer caudal length of the dorsal region, longer standard length (L-S) and shallower body and caudal region, and shorter caudal length of the ventral region. Swimming speeds were related to the combination of deeper body and caudal region, longer caudal length of the ventral region, shallower head depth, shorter caudal length of dorsal region and L-S. These findings suggest that morphological variations which are poorly suited to produce maximum thrust and minimum drag in GH-transgenic C. carpio may be responsible for their lower swimming abilities in comparison with non-transgenic controls.

Understanding the cascode switching process

Cascode circuits are useful for driving normally-on wide-bandgap devices, but the switching process must be properly understood to optimise their design. Little detailed consideration has previously been given to this. This paper proposes an idealised mathematical description of the cascode switching process, which is used to show that the stray inductance between the two devices plays a critical role in switching. This idealised model is used to propose methods for optimising cascode performance in different applications. © 2013 IEEE.