低能离子束介导水稻遗传转化的研究

为研究影响低能离子束介导水稻遗传转化效率的各种因素 ,以粳稻 0 2 42 8、花培 94 鉴 0 9、籼稻明恢 63这 3个水稻品种为实验材料 ,分析了离子的种类、能量、剂量、剂量率等参数对遗传转化的影响 ,建立了有利于遗传转化的组织培养条件和筛选程序。分子生物学检测证明 ,外源GUS报告基因已经整合到水稻基因组中 ,3个水稻品种获得抗性愈伤组织的转化率分别为 1 1 %、1 1 4%和 7 1 % ,获得再生试管苗的转化率分别为 1 5 2 %、1 87%和 1 1 3 %。为应用离子束介导法进行其它对农杆菌不敏感的禾谷类作物转基因提供了方法学的参照 ,并为深入研究离子束与生物体相互作用机制打下了基础。     

钢梁-钢筋混凝土柱节点在国内外的应用研究状况

介绍了美国、日本及我国部分学者在开发和利用RCS组合框架结构时的不同思想、梁柱节，最构造及其组合框架的抗震性能、破坏模式、延性等方面的观点。研究和应用表明，梁柱采用两种不同的材料可以发挥材料的各自优点，从选材上具有合理性和经济性。     

新加坡电子政务案例对江西林业信息化建设的启示

新加坡是全球公认的电子政务发展最为领先的国家。借鉴新加坡信息化与电子政务建设的成功经验,建设好江西省林业信息化与电子政务。     

重离子射线照射对家蚕造血器官的生理效应

用碳离子和氦离子射线局部照射家蚕 5龄第 3日幼虫的造血器官 ,调查了对循环血球密度和种类 ,以及其后生长发育和变态的影响。照射后家蚕变态困难 ,结茧率、化蛹率和羽化率显著降低 ;幼虫血液中血球密度在照射后 8～ 2 4h短暂上升 ,随后快速下降 ,5龄后期血球密度显著低下。上述变化程度随射线剂量增加而更加显著 ,而两种离子射线之间没有明显差异。血液中各种血球的比例虽然没有很大变化 ,但照射后出现了一种大型血球。     

钢筋混凝土悬臂梁的构造问题

针对目前的设计和施工现状,对纵向钢筋的构造和弯曲钢筋的合理设置两个问题进行详细分 析,并介绍了悬臂梁中采用弯起钢筋存在的缺陷。     

Demonstration of two different H2-oxidizing activities in soil using an H2 consumption and a tritium exchange assay

H₂-oxidizing activities were assayed in slurries of four soils by measuring the consumption of H₂ and the exchange of ³H₂ with H₂O at increasing mixing ratios of H₂ or ³H₂. Both H₂ consumption and ³H₂ exchange were abolished by autoclaving or the addition of formaldehyde. The rates of H₂ consumption and ³H₂ exchange were proportional to the quantity of soil used. Both activities increased with increasing concentrations of H₂ or ³H₂ and displayed biphasic kinetics, demonstrating the existence of two different H₂-oxidizing activities, one with a relatively low K _m and V _max, and a second with a relatively high K _m und V _max. The first type of activity was characteristic of abiontic soil hydrogenases, and the second of aerobic H₂-oxidizing bacteria. In contrast to H₂ consumption, which required the presence of either O₂ or ferricyanide, ³H₂ exchange operated equally well without an external electron acceptor. The ³H₂ exchange assay may thus be particularly useful for enrichment of soil hydrogenases which have not yet been isolated and for which no natural electron acceptor is known.     

Characterisation of three novel canine osteosarcoma cell lines producing high levels of matrix metalloproteinases

Three canine osteosarcoma cell lines were established from spontaneous pelvic and radial osteosarcomas. The cell populations cultured exhibited characteristics of malignancy and consisted of adherent, pleomorphic, mostly large spindle-shaped or polyhedral cells, characterised by the presence of numerous cytoplasmic granules and vacuoles. The main ultrastructural features included the presence of abundant rough endoplasmic reticulum and numerous cytoplasmic vesicles, deposit vacuoles and small cytoplasmic protrusions. Zymography showed that the cell lines produce high levels of MMP-2 and MMP-9, enzymes directly involved in crucial aspects of the metastatic process. Consistent with their osteoblastic lineage and malignant phenotype, all cell lines were immunoreactive to vimentin, osteopontin, PCNA, p53, MMP-2 and MMP-9, while they were negative for cytokeratin, desmin, SMA, Factor VIII, NSE, GFAP, Rb and p21 protein. No retroviral particles or RNA were detected ultrastructurally or with RT-PCR, although the possibility of viral involvement in osteosarcoma cannot be excluded. The new cell lines provide excellent in vitro models that may allow further studies on the pathobiology of canine osteosarcoma to be undertaken.     

电子束辐照灭菌对豆粕营养品质的影响

采用不同剂量(0、0.83、1.56、2.30、4.93、7.84 kGy)的电子束辐照饲用豆粕样品,研究其对饲用豆粕营养品质的影响.结果显示,辐照剂量为0.83 kGy以上时豆粕样品中霉菌总数小于10 CFU/g,辐照剂量为2.30 kGy时豆粕样品中细菌总数下降至100 CFU/g;不同剂量的电子束辐照对豆粕的蛋白质含量、氨基酸的含量与组成、蛋白质溶解度的影响不明显;电子束辐照能影响豆粕的尿素酶活性(P＜0.05),且随着辐照剂量的增加尿素酶活性降低.结果表明,2.30～7.84 kGy剂量的电子束辐照能有效控制豆粕中的微生物,且对豆粕营养品质的影响不显著.     

Experiment and FEM Analysis on the Joint of Inserted Steel Beam

A new composite structure which is composed of steel beam and concrete girder is introduced in fuel electric plant construction. With different height of concrete girders with or without anchor bar, two scale models from an actual project were designed and tested. It is shown that the maximum restraining moment of ends of steel beams is approximately 60kN*m; influence of anchor bar is little; the one with 600mm high concrete beam is damaged by shear, and the others steel beam is damaged by bending failure. Finite element models were built for supplementary analysis, and the result indicates that critical value of the height of concrete beam of different failure modes is 700mm; stiffness of shear key and thickness of floor have great influence on the structure; size of anchor bar has little influence; and width of the end of the steel beam has certain influence.     

Large Span Concrete Box Beam Construction Technology

Combined with the engineering practice, the method of large span post tensioned prestressed box beam construction technology was introduced, which can provide the reference for the similar project.