微生物细胞电镀磁性金属化研究

本文以钝顶螺旋藻细胞为模板,通过电镀工艺在其表面沉积磁性合金来制造螺旋形磁性微粒,对微生物细胞电镀磁性金属化工艺进行研究.通过光学显微镜、扫描电子显微镜、电子能谱、X射线衍射、振动样品磁强计等对电镀磁性化后螺旋藻的细胞形态、表层成分、相结构及静磁性能进行观察与分析.结果表明螺旋藻细胞经电镀处理后表面包覆上一层不含非金属相的铁磁性材料,实现了微生物细胞电镀磁性金属化,这为生物约束成形技术提供了新工艺.在金属化过程中,微生物形体保持良好,细胞表面镀层厚度均匀,镀层为面心立方结构的NiFe合金,颗粒具有软磁特性.此外,对微生物细胞电镀磁性金属化工艺过程的电化学反应机理进行了分析,表明NiFe合金在微生物表面的沉积为异常共沉积.     

大型风电机组变桨距载荷计算与特性分析

以大型水平轴式风电机组电动变桨距系统为研究对象,对其因离心力引起的变桨距载荷、气动力引起的变桨距载荷、重力引起的变桨距载荷等进行深入研究,建立了变桨距载荷计算数学模型.以某1.2MW风电机组为典型算例,对前述变桨距载荷进行了独立和综合的计算与特性分析.结果表明,在叶轮转速、来流风速和节距角一定时,叶轮旋转一周过程中变桨距载荷波动呈相似余弦曲线变化,在不同节距角时波动幅值差异较大.文中提出的风电机组变桨距载荷计算思路与方法具有一定普适性,可为独立变桨距系统深入分析和研究提供理论基础.     

三家子矿6-2煤层瓦斯地质规律研究

通过对南票三家子煤矿瓦斯地质资料的分析,并结合煤层瓦斯含量的现场测定和实验室测试,探讨了断层、构造凹地、煤层围岩、含煤岩系沉积环境以及岩浆侵入等地质因素对6-2煤层瓦斯赋存、分布的影响;夯析了各因素与瓦斯含量的关系,即断层、岩浆侵入破坏了煤体的结构,构造凹地引起的压性应力导致6-2煤层区域性渗透率下降,这些因素对瓦斯的逸散均起了阻碍的作用,因此是影响瓦斯赋存的主控因素。绘制出瓦斯含量等值线图,进而为采掘布置和瓦斯防治工作提供了理论依据。     

引种植物水竹芋捕虫行为的初步观察研究

通过对引种植物水竹芋的观察,发现水竹芋的花具有捕捉昆虫的能力,在此基础上对其花进行了解剖结构特征和捕虫行为的观察,并初步探讨了其捕虫行为的生态学意义.观察研究显示,水竹芋开放花以及即将开放花的花柱具有较强的卷曲能力;未开放以及开放后没有被触及的花的花柱被兜状退化雄蕊包被;当昆虫进入饰变雄蕊群形成的筒状结构而触及到兜状退化雄蕊时,花柱因产生应激反应而迅速卷曲,从而将昆虫捕捉.初步观察研究认为,水竹芋不仅具有捕捉昆虫的能力,而且在水污染处理以及湿地的恢复与重建中具有重要的应用潜力.     

CBERS-02B数据在霍山山前活动断裂带1:5万填图中的应用

利用中巴地球资源卫星02B数据,开展山西霍山山前活动断裂带遥感解译研究,解译获得该断裂带总延伸长度约116km,整体走向NE,按其几何结构可以分为6段,断裂活动在晚更新世以来地层形成的断层陡坎在影像上特征清晰;结合野外调查,认为霍山山前断裂带在全新世以来以垂直运动为主.高分辨率遥感卫星数据可以获取活动构造定量研究中断裂带的长度和分段长度,通过断层构造地貌的解译,可以识别出包括断层陡坎、断层槽谷等构造地貌变形信息,为筛选野外重点工作区域提供帮助.研究表明,高分辨率的中巴地球资源卫星可以有效应用于1:5万活动断层填图工作及活动构造定量研究中.     

黄龙景区钙华沉积对磷酸盐浓度变化敏感性定量研究

为定量研究黄龙地表水中磷酸盐浓度变化对钙华沉积速率的影响,明确景区各景点钙华沉积速率对磷酸盐浓度变化的敏感性大小,于6月下旬~11月上旬,在黄龙风景区5个主要景点设置监测点,定期采集钙华沉积样和磷酸盐水样,利用SPSS统计软件对实验数据进行分析。结果发现,黄龙风景区各景点地表水中磷酸盐浓度与钙华沉积速率皆呈显著负相关性,说明地表水中磷酸盐浓度变化可能已对钙华沉积产生影响。景区各景点钙华沉积速率对磷酸盐浓度变化的敏感性大小依次是金砂铺地、马蹄海、迎宾池、五彩池、争艳池。     

地下水位气压效应的消除及主要气压影响分波的识别

气压变化对地下水位微动态存在影响,而地下水位微动态变化通常携带了大量构造活动和地震异常信息,消除地下水位的气压效应对于有效识别地震异常信息具有重要意义.通过识别地下水位中主要气压影响分波并分析其变化,可以进一步探求地震过程中含水层介质的变化,进而达到预测地震的目的.本文以2008年5月12日汶川地震为例,利用南溪、巢湖与邛崃井的地下水位与气压观测数据,进行了地下水位的气压效应消除和影响地下水位的主要气压分波识别研究.通过2种回归方法得到了消除气压影响后的校正水位;利用调和分析法结合频谱分析识别了影响水位波动的气压分波;对地震前后影响井水位变化的气压分波进行了对比研究,发现地震前后主要气压影响分波发生了改变,各气压分波振幅也有不同程度的增减,这可能与气压分波各自周期性变化有关,也可能是地震造成含水层特性发生改变从而使井水位对气压的响应改变所致.     

超重力水溶液金属镍电沉积及极化反应研究

以电沉积镍箔为例，在离心力场条件下，研究了超重力对水溶液金属电沉积的影响．结果表明超重力电沉积金属镍，晶粒细化、韧性和抗拉强度显著提高；杂质元素H含量减少，但电效降低；超重力场促进析氢反应，析氢过电位降低；超重力场促进溶液中离子传质，降低过电位，提高极限电流密度；对于离心力场超重力条件下的电沉积、电极反应及材料组织性能还与惯性力和电流方向有关，惯性力与电流方向同向有利于获得组织结构致密性能更好的电沉积材料．     

东太平洋海盆多金属结核的物质组构及形成环境意义

运用反光显微镜、电子探针对东太平洋CC区多金属结核中壳层构造及鲕粒的韵律层进行了初步的研究。结果表明，多金属结核的构造及其形成是环境的反映。结核中鲕粒的微纹层构造是结核形成时的一个较短时间段内海洋环境的演化反映。鲕粒纹层的反射率与鲕粒中的δ-MnO2结晶程度有关，每层的元素含量与形成时环境的Eh、pH值有关，元素含量的变化与结晶程度有着相同的变化规律。     

美调查人员就提高航天飞机安全性提出新建议

美“哥伦比亚”号航天飞机事故调查人员日前指出 ,美国宇航局应该寻找办法在航天飞机发射升空过程中加强对外部燃料箱等部件的拍照 ,并将结果及时传回地面。这是他们就提出航天飞机安全性而提出的第 5条建议。调查人员在一份新闻公报中指出 ,在发射升空过程中获取航天飞机部件的高质量照片 ,能够为检测意外脱落的碎片等提供必要数据。在外部燃料箱与航天飞机分离后及时将照片传回 ,对于确定是否有碎片从这一部件脱落具有重要帮助。鉴于目前还无法彻底杜绝产生碎片 ,及早检测是否有碎片击中航天飞机两翼底侧的隔热板 ,也将有助于提高飞行安全…     

区域性UDDI的节点间数据同步技术研究

目前区域性UDDI大多为单节点,有些虽为多节点但节点之间不是采用数据同步而是使用统一的数据库。这导致整个系统的安全性不高、扩展性不好和效率低下等问题。因此本文采用P2P技术和报文技术实现了区域性UDDI系统中各节点的数据同步,很好地解决了以上问题,实现了“一次注册,到处发布”的功能,提高了系统的安全性、可扩展性和效率。     

Neurofilament proteins in neurodegenerative diseases

The function of neurofilaments, the major component in large myelinated neurons, is not well understood even though they were discovered as structures over 100 years ago. Recent studies have suggested that neuro-filaments are closely related to many neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson disease Alzheimer disease, and diabetes. Using in vitro assays, cultures and transgenic mice, these studies provided new insights into neurofilament function. The function of each subunit, the relationship of neurofilaments with other cytoskeletal elements and their clinical significance are topics of increasing attention.Received 22 June 2004; received after revision 4 August 2004; accepted 19 August 2004     

Nitric oxide biosynthesis, nitric oxide synthase inhibitors and arginase competition for L-arginine utilization

Nitric oxide (NO) is a recently discovered mediator produced by mammalian cells. It plays a key role in neurotransmission, control of blood pressure, and cellular defense mechanisms. Nitric oxide synthases (NOSs) catalyze the oxidation of L-arginine to NO and L-citrulline. NOSs are unique enzymes in that they possess on the same polypeptidic chain a reductase domain and an oxygenase domain closely related to cytochrome P450s. NO and superoxide formation as well as NOS stability are finely regulated by Ca²⁺/calmodulin interactions, by the cofactor tetrahydrobiopterin, and by substrate availability. Strong interactions between the L-arginine-metabolizing enzymes are clearly demonstrated by competition between NOSs and arginases for L-arginine utilization, and by potent inhibition of arginase activity by N^ω-hydroxy-L-arginine, an intermediate in the L-arginine to NO pathway.     

Occurrence,distribution and nature of neuropeptide Y in the rat pancreas

Summary Significant quantities of a newly discovered peptide, neuropeptide Y, were found in the rat pancreas, where they were localized to nerves in the exocrine parenchyma and around arterial and ductal structures. Although unaffected by surgical parasympathectomy, the periarterial and periductal nerves were abolished by chemical sympathectomy, suggesting that NPY is partially costored with sympathetic transmitters in nerve fibers.     

Occurrence, distribution and nature of neuropeptide Y in the rat pancreas

Significant quantities of a newly discovered peptide, neuropeptide Y, were found in the rat pancreas, where they were localized to nerves in the exocrine parenchyma and around arterial and ductal structures. Although unaffected by surgical parasympathectomy, the periarterial and periductal nerves were abolished by chemical sympathectomy, suggesting that NPY is partially costored with sympathetic transmitters in nerve fibers.     

Lactoferrin

The first function attributed to lactoferrin (Lf), an iron binding protein belonging to the non-immune natural defences, was antimicrobial activity that depended on its capacity to sequester iron. Iron-independent microbicidal activities, requiring direct interaction between this cationic protein and microbial surface components, were later demonstrated. Many other anti-microbial and anti-viral functions have since been ascribed to Lf. In mucosal secretions, iron and Lf modulate the motility and aggregation of pathogenic bacteria. Lf inhibits bacterial adhesion on abiotic surfaces through ionic binding to biomaterials, or specific binding to bacterial structures or both. Lf inhibition of bacterial adhesion to host cells requires Lf binding to bacteria and/or host cells. Lf hinders microbial internalization by binding to both glycosaminoglycans and bacterial proteins which can be degraded by Lf-mediated proteolysis. Moreover, Lf internalisation and localisation to the host cell nuclei could modulate bacterial entry into cells through gene regulation. Finally, the capability of Lf to exert antiviral activity, through its binding to host cells and/or viral particles, strengthens the idea that it is an important brick in the mucosal wall, effective against both microbial and viral attacks.     

黑腹果蝇品系纯合体杂交后代翅型变异的遗传分析

目的探究实验室条件下果蝇杂交后代所表现出的基因连锁、互换与自由组合效应,计算白眼、卷刚毛、小翅基因座位间的距离,并探索可能的基因互作。方法将三隐性（白眼、卷刚毛、小翅）与残翅两种品系的果蝇进行杂交,并使F1代互交,对正反交的F2代进行表型数据统计分析。结果发现F2代出现新性状小皱翅,将其分为3种情况进行讨论,计算出了3个基因座位闻的距离。结论果蝇小翅和残翅基因互作产生了新性状小皱翅;在统计上它是一种“例外”新性状,而不是小翅或残翅范畴里的特情。     

Host-defense peptides: from biology to therapeutic strategies

Primitive innate defense mechanisms in the form of gene-encoded antimicrobial peptides are now considered as potential candidates for the development of new therapeutics. They are well known for their function as the first protective barrier of all organisms against microbial infections. In addition, emerging studies reveal that they assist in modulating the host immune system. The biological properties of these host-defense peptides, their role in human health, their cell selectivity and related molecular mechanisms are discussed in this multi-author review along with the strategies to transform them or their peptidomimetics into clinically usable drugs.     

Paneth cell α-defensins in enteric innate immunity

Paneth cells at the base of small intestinal crypts of Lieberkühn secrete high levels of α-defensins in response to cholinergic and microbial stimuli. Paneth cell α-defensins are broad spectrum microbicides that function in the extracellular environment of the intestinal lumen, and they are responsible for the majority of secreted bactericidal peptide activity. Paneth cell α-defensins confer immunity to oral infection by Salmonella enterica serovar Typhimurium, and they are major determinants of the composition of the small intestinal microbiome. In addition to host defense molecules such as α-defensins, lysozyme, and Pla2g2a, Paneth cells also produce and release proinflammatory mediators as components of secretory granules. Disruption of Paneth cell homeostasis, with subsequent induction of endoplasmic reticulum stress, autophagy, or apoptosis, contributes to inflammation in diverse genetic and experimental mouse models.     

Implications of toxins in the ecology and evolution of plant pathogenic microorganisms: Bacteria

This review attempts to rationalise what is known about bacterial phytotoxins and associate it with the ecology and possible evolution of the producing organisms. Study of non-toxin producing variants gives insight into the ecological role of the toxin. Elucidation of chemical structures of phytotoxins has shown that many exist as families of analogous compounds. Studies on the variation of chemical structures and how they are distributed across species and genera can lead to development of hypotheses on evolutionary relationships. Knowledge on biosynthetic pathways to tosins allows recognition of specific enzymatic steps involved in developing the characteristic features of the structures. Phytotoxins often have a potent biochemical activity, and in some cases the producing organism has associated mechanisms to prevent action of the toxin upon itself; in such cases toxigenesis is clearly not a chance event. The various aspects of bacterial toxigenesis indicate that bacterial phytotoxins are special secondary metabolic products that play beneficial roles to the producing organisms in their various ecological niches.