草地与农牧交错带退化生态系统重建及防治途径

草地不仅是草地畜牧业的基地，而且在生态环境保护与建设方面的作用尤为重要。草原与农牧交错带，即不同于西部牧区，也不同于东部农区。根据它在地理、气候、农林牧产业结构、生态、经济、文化、社会等方面具有自己独特地位的实际情况，因地制宜提出了相应之对策，为国家在西部大开发和草地与农牧交错带生态环境的恢复提供科学依据。     

Effects of oestradiol and progesterone on FSH and LH contents of the pituitaries and blood of ovariectomized ewes

Zusammenfassung Zufuhr von 20 µg Östradiolbenzoat an zwei sich folgenden Tagen verursachte bei ovariektomierten Mutterschafen keine Veränderung im FSH- und LH-Gehalt von Hypophyse und Serum. Nach cinmaliger Verabreichung von 10 mg Progesteron (nach östradiolbehandlung) stieg das FSH im Blut an. Ebenso ergab Zufuhr von 20 mg Progesteron bei mit Östrogen behandelten Mutterschafen Anstieg des LH-Gehaltes im Blut.     

Temperature variation and the function of complement and antibody of amphibia

Summary Temperature treatment of sera of erythrocyte immunized adults of 3 amphibian species has shown that cooling enhances antigen-antibody complexing and does not alter complement function in vitro. These findings bear on understanding in vivo temperature immunosuppression in poikilotherms.This research was partially supported by a grant No. AI-12846 from the National Institutes of Health, Bethesda, Md, USA. The authors are grateful for the technical assistance of Ms J. S. Ruben.     

Structuralism and the conformity of mathematics and nature

Structuralists typically appeal to some variant of the widely popular ‘mapping’ account of mathematical representation to suggest that mathematics is applied in modern science to represent the world’s physical structure. However, in this paper, I argue that this realist interpretation of the ‘mapping’ account presupposes that physical systems possess an ‘assumed structure’ that is at odds with modern physical theory. Through two detailed case studies concerning the use of the differential and variational calculus in modern dynamics, I show that the formal structure that we need to assume in order to apply the mapping account is inconsistent with the way in which mathematics is applied in modern physics. The problem is that a realist interpretation of the ‘mapping’ account imposes too severe of a constraint on the conformity that must exist between mathematics and nature in order for mathematics to represent the structure of a physical system.     

Estimation of serotonin and its action on oviducts and uteri of some oviparous and viviparous insects

Summary Serotonin was not found in the oviducts ofBlabera gigantea, Clitumnus extradentatus nor in the uterus ofGlossina, but it is present in the uterus ofBlabera. It is also found in the central nervous system of all three insects. In vitro experiments confirm these data by showing that serotonin increases the contractions of the uterus ofBlabera, but has no effect on the uterus ofGlossina.     

Mutagenicity and toxicity of chloroethylene oxide and chloroacetaldehyde

Summary Exposure of severaltrp-auxotrophicEscherichia coli strains, carrying base0pair substitutions, to chloroethylene oxide or chloroacetaldehyde (two metabolites of vinyl chloride) increased the mutation frequency to tryptophan prototrophy. Strong cytotoxic and mutagenic effects were observed with 2.5 mM chloroethylene oxide, while a higher concentration of chloroacetaldehyde (100 mM) exhibited a mutagenic effect which was 400 times lower.I am grateful to Prof. G. Michel, Laboratoire de Biochimie Microbienne, and to Dr H. Bartsch, International Agency for Research on Cancer, for the support of this work. I wish to thank Dr F. Besson-Simien and Dr A. Barbin for their collaboration.     

The metabolism and function of sphingolipids and glycosphingolipids

Sphingolipids and glycosphingolipids are emerging as major players in many facets of cell physiology and pathophysiology. We now present an overview of sphingolipid biochemistry and physiology, followed by a brief presentation of recent advances in translational research related to sphingolipids. In discussing sphingolipid biochemistry, we focus on the structure of sphingolipids, and their biosynthetic pathways – the recent identification of most of the enzymes in this pathway has led to significant advances and better characterization of a number of the biosynthetic steps, and the relationship between them. We then discuss some roles of sphingolipids in cell physiology, particularly those of ceramide and sphingosine-1-phosphate, and mention current views about how these lipids act in signal transduction pathways. We end with a discussion of sphingolipids and glycosphingolipids in the etiology and pathology of a number of diseases, such as cancer, immunity, cystic fibrosis, emphysema, diabetes, and sepsis, areas in which sphingolipids are beginning to take a central position, even though many of the details remain to be elucidated. Received 13 February 2007; received after revision 19 April 2007; accepted 26 April 2007     

镁及镁合金的研究现状与进展

文献综述了镁及镁合金的性能特性，镁合金系列，国内外镁合金的研究现状，镁合金表面处理的各种方法以及镁合金在航空航天，汽车工业，电子工业及民用各个领域的广泛应用，展望了镁合金的应用前景。     

Mutagenicity and toxicity of chloroethylene oxide and chloroacetaldehyde

Exposure of several trp-auxotrophic Escherichia coli strains, carrying base-pair substitutions, to chloroethylene oxide or chloroacetaldehyde (two metabolites of vinyl chloride) increased the mutation frequency to tryptophan prototrophy. Strong cytotoxic and mutagenic effects were observed with 2.5 mM chloroethylene oxide, while a higher concentration of chloroacetaldehyde (100 mM) exhibited a mutagenic effect which was 400 times lower.     

The influence of oestrogen and thyroid on the pituitary and blood content of FSH and LH

Résumé L'effet de l'administration du «Benzoate d'stradiol» et des hormones thyroïdales seuls ou en combinaison sur le FSH et LH contenus dans le sang et les hypophyses des femelles rats castrés a été étudié. Il a été trouvé que l'stradiol et l'extract de la thyroïde quand ils sont administrés seuls produisent une baisse, dans le sang, du FSH et une hausse du LH. L'administration combinée de ces deux hormones renforce cet effet.     

俄罗斯国家科技基础与普京政府科技政策价值取向

人类社会在经历了漫长的农业经济和工业经济时代后，随着21世纪的到来即将进入知识经济时代，从前苏联到俄罗斯曾奠定了无愧于这一新时代的科技基础，将会成为攻占未来世界市场制高点的一支劲旅。普京政府在这方面充满信心，并且以重振大国雄风为目标而采取了积极推进的科技政策，其价值取向是在科技开发中实际国际化、市场化、产业化和法制化，不断加大本国经济在国际社会的影响力、竞争力、辐射力和吸引力。除此之外，根据中俄两国战略协作伙伴关系的发展要求，双方正在努力使科技合作成为这一关系的题中应有之义，共同开发新项目，改造传统产业，发展宇航业，加强军领域合作，开展人才交流与培训，大力发展教育事业，以科技合作来提升经贸合作水平，进而实现两国经贸合作战略升级的宏大目标争取到2020年使双边经贸额度达到1000亿美元，届时将与中美、中日之间的贸易额度基本持平，为建立世界新秩序作出贡献。     

Specific gravity of epididymal and ejaculated bull spermatozoa and of their parts

Zusammenfassung Es wird ein auffallender Unterschied im spezifischen Gewicht von epididymalen und ejakulierten Bullenspermatozoen durch Gleichgewichtszentrifugierung in Ficollgradienten festgestellt. Ähnliche Versuche mit Kopf- bzw, Mittelstück-Schwanz-Fragmenten, aus ejakulierten Spermien mittelst Ultraschallbehandlung erhalten, zeigen bei Vergleich mit früheren Angaben, dass diese Veränderung nur den Kopf betrifft.     

近现代中国农业科学技术发展回顾与展望

本文回顾了近现代中国农业科学院技术发展的历程，阐述了中国农业科学技术发展取得的成就，总结了半个世纪以来中国农业科技进步的主要特征，对21世纪中国农业发展前景进行了分析展望，作者认为，坚持共产党的领导，走社会主义道路，中国才结束了积贫积弱的历史，才实现中国历史上最广泛最深刻的社会，才使中国人民掌握了自己的命运，中国基本解决温饱问题，支撑现代化建设两步走战略目标的提前实现，一个很重要的因素就是科学技术取得长足的进步，对农业、农村发展做出了重要贡献，21世纪，中国农业担负的任务要比改革开放20年来解决温饱进入小康更为繁重，这是中国现代化进程中最艰巨的历史性任务，科学技术的跨越发展将为21世纪中国实现农业现代化发挥决定性的作用。     

Properties and modes of action of specific and non-specific phospholipid transfer proteins

We have described the mode of action of the phosphatidylcholine transfer protein (PC-TP), the phosphatidylinositol transfer protein (PI-TP) and the non-specific lipid transfer protein (nsL-TP) isolated from bovine and rat tissues. PC-TP and PI-TP specifically bind one phospholipid molecule to be carried between membranes. PC-TP, and most likely PI-TP as well, have independent binding sites for the sn-1- and sn-2-fatty acyl chains. These sites have different properties, which may explain the ability of PC-TP and PI-TP to discriminate between positional phospholipid isomers. nsL-TP, which is identical to sterol carrier protein 2, transfers all common phospholipids, cholesterol and oxysterol derivatives between membranes. This protein is very efficient in mediating a net mass transfer of lipids to lipid-deficient membranes. Models for its mode of action, which is clearly different from that of PC-TP and PI-TP, are presented.