Regeneration in crustacean motoneurons: evidence for axonal fusion

Crayfish motor axons remain excitable for over 100 days after severance from their central cell bodies, and continue to store and release normal amounts of transmitter substance. Evidence indicates that regeneration occurs by fusion of the central process with its surviving peripheral segment.     

Structural evidence for evolution of the beta/alpha barrel scaffold by gene duplication and fusion

The atomic structures of two proteins in the histidine biosynthesis pathway consist of beta/alpha barrels with a twofold repeat pattern. It is likely that these proteins evolved by twofold gene duplication and gene fusion from a common half-barrel ancestor. These ancestral domains are not visible as independent domains in the extant proteins but can be inferred from a combination of sequence and structural analysis. The detection of subdomain structures may be useful in efforts to search genome sequences for functionally and structurally related proteins.     

Biochemical and cytological evidence for triple hybrid cell line formed from fusion of three different cells

Hybrids between two parental lines of somatic cells have been observed in various genomic multiplicities by ourselves and others. Possible explanations for the higher multiplicities include the fusion of cells in a 1:1 ratio with one genomic set undergoing an asynchronous replication either before or after fusion or the fusion of two or more cells. We now provide evidence for multiple genomic hybrids arising from the fusion of more than two cells in a mixture of three different cell lines. This proof is based on unique chromosomal and biochemical markers characteristic of the three parental cell lines. The distinctive phenotypes of all three lines are expressed in a clonally derived hybrid. Thus, we conclude that long-term, proliferating somatic cell hybrids can arise from the fusion of three or more cells.     

《浙江农业学报》2003-2005年载文信息分析

运用文献计量学方法,对《浙江农业学报》2003—2005年发表论文的自有计量指标——载文量、出版时滞、基金论文比,参考文献量、平均引文率、篇均作者数、地区分布数、机构数、国际论文比等项目进行统计分析,并引用2004—2006年版《中国科技期刊引证报告》的《浙江农业学报》被引计量指标——总被引频次、影响因子、即年指标、他引率、引用期刊数、被引半衰期等项目进行了评述。通过分析比较,最后提出了扩大《浙江农业学报》学术影响力的建议。     

《新疆农业科学》2007年—2011年刊登论文学科分布分析

通过统计2007～2011年《新疆农业科学》刊登论文的学科分布情况,可以看出五年来,作物育种与栽培发文量最高,在年度中所占比例也最高。编辑部不但要关注基础学科发展,还要加强对农业节水技术、农业机械学科的征稿力度,以便全部反映新疆农业的发展。     

西文图书招标采购评价指标探讨

结合首都医科大学图书馆的工作实际,分析了西文图书招标采购过程中涉及的图书价格、供应商服务、供应商资质与信誉等主要评价指标,探讨了这些评价指标的内在影响因素及建议分值,为图书馆公正合理地评价与选择图书供应商提供参考。     

《浙江林学院学报》1993～2002年载文分析

应用文献计量学方法，对《浙江林学院学报》1993-2002年所刊论文进行了统计分析。结果表明：《浙江林学院学报》载文量和刊容量增加，刊容系数下降，出版时滞为246d；论文平均作者数为3．22人，2人以上合著率为80．2％，与全国科技论文的合著规律相符；作者年龄结构合理，队伍稳定；主要报道森林基础、森林培育和育种、森林经理和经营及森林保护等学科的论文，具有鲜明的学科特色和地方特色。表7参5     

Anaerobic dormancy quantified in artemia embryos: a calorimetric test of the control mechanism

Continuous measurement of heat dissipation from brine shrimp embryos during reversible transitions from aerobic development to anaerobic dormancy demonstrates a primary role for intracellular pH(pH(i))in this metabolic switching. Artificially elevating the depressed pH(i) during anoxia by adding ammonia markedly reactivates metabolism, as judged by increases in heat dissipation, trehalose catabolism, and the ratio of adenosine triphosphate to adenosine diphosphate. Energy flow during anaerobic dormancy is suppressed to 2.4 percent of aerobic values, which is the lowest percentage thus far reported for euryoxic animals. Use of diguanosine tetraphosphate stores cannot account for this observed heat dissipation. Thus, mobilizing trace amounts of trehalose may explain the energy metabolism during quiescence.     

2003～2006年《广西农业科学》载文作者群分析

为总结办刊经验,提高刊物质量,对2003~2006年《广西农业科学》载文第一作者的基本情况、论文合作情况、作者所属系统及地区分布、作者所在单位等信息资料进行统计分析。结果表明,《广西农业科学》已拥有一批高素质、相对稳定的以中青年科技人员为主的活跃的作者群,并具有一定的知名度和影响力。今后,应努力提高《广西农业科学》的学术性和知名度,提高办刊质量,以吸引更多的高素质作者投稿,增加作者源。     

Seismic evidence for deep-water transportation in the mantle

We report seismic evidence for the transportation of water into the deep mantle in the subduction zone beneath northeastern Japan. Our data indicate that water is released from the hydrated oceanic crust at shallow depths (< approximately 100 kilometers) and then forms a channel of hydrated mantle material on top of the subducting plate that is the pathway for water into the deep mantle. Our result provides direct evidence that shows how water is transported from the ocean to the deep mantle in a cold subduction zone environment.     

Two-million-year record of deuterium depletion in great basin ground waters

Fluid inclusions in uranium series-dated calcitic veins from the southern Great Basin record a reduction of 40 per mil in the deuterium content of ground-water recharge during the Pleistocene. This variation is tentatively attributed to major uplift of the Sierra Nevada Range and the Transverse Ranges during this epoch with attendant increasing orographic depletion of deuterium from inland-bound Pacific storms.     

《大连海洋大学学报》2003年-2012年高被引论文的研究

利用CNKI中国引文数据库,以2003年-2012年《大连海洋大学学报》最高被引30篇论文为基础数据,通过进一步分析,探讨高引论文形成的主要因素.结果表明：学科特色、高水平基金、海洋水产新兴热点领域等成为高被引论文的主要因素,而作者职称等因素作用不明显.研究可为《大连海洋大学学报》未来的选题、组稿等提供借鉴.     

RNA-mediated metal-metal bond formation in the synthesis of hexagonal palladium nanoparticles

RNA sequences have been discovered that mediate the growth of hexagonal palladium nanoparticles. In vitro selection techniques were used to evolve an initial library of approximately 10(14) unique RNA sequences through eight cycles of selection to yield several active sequence families. Of the five families, all representative members could form crystalline hexagonal palladium platelets. The palladium particle growth occurred in aqueous solution at ambient temperature, without any endogenous reducing agent, and at low concentrations of metal precursor (100 micromolar). Relative to metal precursor, the RNA concentration was significantly lower (1 micromolar), yet micrometer-size crystalline hexagonal palladium particles were formed rapidly (7.5 to 1 minutes).     

Measurements of the equation of state of deuterium at the fluid insulator-metal transition

A high-intensity laser was used to shock-compress liquid deuterium to pressures from 22 to 340 gigapascals. In this regime deuterium is predicted to transform from an insulating molecular fluid to an atomic metallic fluid. Shock densities and pressures, determined by radiography, revealed an increase in compressibility near 100 gigapascals indicative of such a transition. Velocity interferometry measurements, obtained by reflecting a laser probe directly off the shock front in flight, demonstrated that deuterium shocked above 55 gigapascals has an electrical conductivity characteristic of a liquid metal and independently confirmed the radiography.     

Biogeochemical evidence for dinoflagellate ancestors in the early cambrian

Dinoflagellates are single-celled organisms that reflect the ecological conditions in modern oceans and lakes. Ultrastructural data and molecular phylogeny suggest that they originated in the Neoproterozoic, yet dinoflagellate ancestors are classified only to the Middle Triassic ( approximately 240 million years ago). Examination of dinoflagellate-specific biological markers (dinosteranes and 4alpha-methyl-24-ethylcholestane) in concentrated microfossils with known morphology identified ancient dinoflagellate ancestors from the Early Cambrian ( approximately 520 million years ago).