用RAPD技术对我国栉孔扇贝野生种群与养殖群体的遗传结构及其遗传分化的研究

利用RAPD技术对我国栉孔扇贝野生种群和养殖群体的遗传结构及其分化进行了研究，在对20个野生栉孔扇贝和20个养殖栉孔扇贝的基因组DNA的检测中，20个10碱基的随机引物共扩增出153条清晰可分辨的DNA片段，片段的长度为200－3000bp其中多态性片段分别为116和112条，野生种群和养殖群体的多态位点比例分别为75．82％，和73．47％，杂合度分别为0．27和0．26。根据基因频率计算出两个群体的近交系数为0．00129，遗传距离为0．028。栉孔扇贝野生种群的多态位点比例和杂合度处于较高水平，说明我国栉孔扇贝野生种群的遗传多样性水平较高，种质资源尚处于较好状态，应制定相应的渔业生产和管理措施加以保护，养殖群体的多态位点比例和杂合度都低于野生种群，这与人工累代养殖过程中，群体较小，近交机会增加有关。     

牙鲆GH基因外显子多态性与生长性状关系的初步研究

以一个牙鲆养殖群体中的100个个体为实验材料,根据其生长激素(GH)基因的五个外显子序列设计引物,进行PCR扩增,通过SSCP分析技术对其进行检测,结果表明该群体生长激素基因的第四个外显子存在多态性.共检测到两种基因型,其中AA型个体占88%,AB型个体占12%;DNA测序结果表明,AB型在第1763位发生碱基突变,c→t,与AA型同源性达到99%,同时发现不同基因型的个体在体重和头长上表现出显著的差异(P＜0.05).上述结果表明利用PCR-SSCP技术可以检测到牙鲆生长激素基因外显子部分存在序列遗传多态性,且该多态性与其生长的某些性状具有一定的连锁关系,为将来进行标记辅助选育奠定了基础.     

丝羽乌骨鸡微卫星多态性及其与产蛋性能的关系

选用12个微卫星标记，通过对丝羽乌骨鸡多态性扩增，计算出这些微卫星标记座位的等位基因频率、多态信息含量、群体杂合度。通过标记多态性与产蛋性状的最小二乘分析和多重比较，进行了分子标记与产蛋性状的相关分析。结果表明，12个微卫星标记中，9个表现出丰富的多态性。微卫星标记座位平均检测到4．5556个等位基因(3～7个)。9个微卫星标记平均多态信息含量为0．6072。标记平均杂合度为0．7423。通过最小二乘分析，检测到4个标记G31913、X82867、Z95315、G01672与3种性能指标(4个月连产蛋量、开产蛋重、500天产蛋量)存在显著相关。标记G31913中基因型AB的开产体重最小二乘均值最高，Z95315的基因型CC的开产蛋重、开产体重最小二乘均值最高，标记G31913的基因型AB和标记Z95315的基因型CC有望作为开产蛋重、开产体重早期选择辅助标记，标记X82867基因型为CD的产蛋量较低，而基因型为AB的产蛋量相应较高。     

中国对虾人工选育快速生长群体不同世代间的AFLP分析

利用7对AFLP引物组合检测了中国对虾连续五代选育群体基因组DNA的遗传结构,根据AFLP分析结果计算了选育世代群体间的遗传相似系数和遗传距离.结果表明,AFLP标记表现出较高的多态检测效率,7对引物共产生500余条带,平均每对引物组合检测到33.7个多态性标记,平均杂合度为0.0854～0.1025,非常适合于遗传多样性分析.结果显示,随着选育世代的增加,选育群体的遗传多样性呈现下降趋势,但随着选育时间的延长,群体之间的分化逐渐降低,群体的遗传结构开始趋于稳定,成为一个品系.     

三种鲆鲽鱼养殖群体的遗传多样性及特异性AFLP标记研究

应用AFLP技术对条斑星鲽、星斑川鲽及漠斑牙鲆的养殖群体进行遗传分析。8对EcoRI／MseI 引物在条斑星鲽、星斑川鲽、漠斑牙鲆养殖群体中分别得到196、207、187条扩增带。其群体的多态位点比例分别为26.02％、25.12％、39.57％,Nei遗传多样性指数和Shannon遗传多样性指数分别为0.1101和0.1587,0.1008和0.1465,0.1566和0.2238。结果表明,条斑星鲽和星斑川鲽养殖群体的遗传变异水平相对较低,而漠斑牙鲆的遗传变异水平相对较高。同时还筛选获得了这3种鲆鲽鱼的共享标记19个,种的特有标记依次为44、45、34个。并根据两两间的遗传距离构建了UMPGA聚类关系图,从分子生物学角度衡量了其亲缘关系。     

牙鲆同质雌核发育人工诱导研究

采用紫外线照射对牙鲆(Paralichthys olivaceus)精子遗传物质进行完全灭活,灭活精子与牙鲆卵子授精获得雌核发育单倍体受精卵,再通过冷休克或静水压法对其进行倍性恢复,成功诱导出同质雌核发育牙鲆.牙鲆精子遗传灭活的最适紫外照射剂量为3.6×10-3J/mm2(照射时间为180s);(15±0.2)℃水温下冷休克法诱导的最适条件为受精后85min,0～2℃水温处理45min;静水压法的最适诱导参数为受精后85min,600kg/cm2压力处理6min,诱导效率静水压法明显高于冷休克法.两种方法诱导组胚胎发育较对照组在原肠期前都有明显滞后现象,开口前同质雌核发育仔鱼比异质雌核发育仔鱼存活率低,但二者全长生长无显著差异(P＜0.05).这些结果为牙鲆纯系建立及其应用提供了重要依据.     

天鹅洲保护区长江江豚AFLP遗传多样性分析

应用AFLP技术对天鹅洲白豚国家级自然保护区的长江江豚 (Neophocaenaphocaenoidesasiaeorientalis)群体进行了遗传多样性分析。每个AFLP引物组合在群体中检测到 0到 6个不等的多态性片段 ,平均为 2 .4 8个。 2 1个引物组合共揭示了 1139个座位 ,其中 5 2个座位具有多态性。多态性座位所占比例为 4 .6 %。分析显示群体的遗传期望杂合度 (He)为 0 .4 430± (SE0 .0 12 2 2 )。研究结果表明保护区长江江豚群体具有适度的核DNA遗传多样性水平。为了该群体的长期生存与发展 ,更多的具有不同遗传变异的个体应该被迁入保护区 ,以形成更大的群体 ,获得更好的群体遗传结构     

牙鲆生长激素基因的克隆及其在大肠杆菌中的融合表达

采用逆转录聚合酶链式反应(RT-PCR)方法,从牙鲆(Paralichthys olivaceus)脑垂体总RNA中扩增出编码牙鲆生长素(GH)成熟肽基因序列。重组至融合表达载体pGEX-4T-3中,构建成牙鲆GH基因融合表达载体pGEX-gh,转化大肠杆菌BL21(DF3),筛选阳性克隆,IVIG诱导表达。经SDS-PAGE电泳显示在45kD处有特异的蛋白条带出现,该蛋白的表达量随诱导时间的延长而增加,3h达最高值,达到细胞总蛋白的18．3％。该融合蛋白在胞内主要以包涵体状态存在,经优化表达条件,成功地获得了可溶性的融合蛋白,经Glutathione Sepharase 4B凝胶纯化后用Western-blotting检测表明其为牙鲆生长激素,并通过酶联免疫吸附受体法证实其具有生物学活性。     

牙鲆淋巴囊肿病的PCR诊断方法研究

以中国养殖牙鲆 (Paralichthysolivaceus)淋巴囊肿病毒 (Lymphocystisdiseasevirus,LCDVcn)主要衣壳蛋白 (majorcapsidprotein ,MCP)基因的中间保守序列为目标基因 ,设计了一对特异性引物。该引物可扩增出 172bp的病毒DNA片段 ,其最小DNA检出量为 0 0 183ng。用PCR法从人工感染淋巴囊肿病毒 3天的牙鲆血、鳃、肝、脾、肠、胃及自然发病牙鲆的肿瘤中 ,分别检测到了LCDV的存在。本实验结果证明 ,PCR法对于早期检测LCDV是十分有效的。     

小麦品种“Lee”中抗条锈病基因的 PAPD 标记

共用３８０个１０碱基随机引物，对抗条锈病基因ＹｒＬｅｅ的近等基因系进行了ＲＡＰＤ分析，其中有两个引物在抗病的近等基因系ＹｒＬｅｅ／６＊Ｔａｉｃｈｕｎｇ２９Ｆ３和基因供体亲本“Ｌｅｅ”中扩增出了特异的ＤＮＡ片段，而在轮回亲本“Ｔａｉｃｈｕｎｇ２９”中没有扩增出同样的ＤＮＡ片段。引物ＯＰＲ－７扩增出的ＤＮＡ片段长度约为４６５ｂｐ，引物ＯＰＲ－９扩增出的ＤＮＡ片段长度约为６６７ｂｐ。用基因供体亲本“Ｌｅｅ”与感病品种“铭贤１６９”杂交的Ｆ２代分离群体（１８９株植株）进行的遗传连锁性分析表明，引物ＯＰＲ－７扩增出的特异ＤＮＡ片段与ＹｒＬｅｅ基因紧密连锁。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.