基于文献计量的氮化镓照明材料研究态势分析

采用文献计量方法对SCIE文献数据库中1990~2016年与氮化镓(GaN)照明材料相关的科研产出进行分析,得到国内外在该领域的研究现状及趋势。通过对GaN照明材料领域科研活动基本特征的分析发现,发达国家在该领域的整体科研实力明显强于发展中国家,美国在多项统计指标中均占据主导地位。利用VOSviewer软件对文献内容进行深入挖掘,得到目前国内外在该领域的研究热点、主要产出国家/地区及机构的合作网络,以及该领域主要论文的引文情况。最后,通过对论文数、总被引数、h-index因子、ESI高被引论文数、高产机构和期刊等6项指标值进行标准化计算,对比了我国与领先国家/地区在GaN照明领域的科研综合竞争力,并分析了我国在该领域的科研特点,提出相关发展建议。     

基于文献计量分析的全球系统动力学研究力量分布及合作网络研究

本研究基于社会网络理论,以美国科学引文索引数据库扩展版(SCI-EXPANDED)和社会科学引文索引数据库(SSCI)收录,发表于1981~2013年间的1160篇论文题录数据为研究对象,对系统动力学领域的研究力量分布及全球合作网络进行了分析。研究发现:过去30余年来越来越多国家/研究机构涉足于系统动力学研究。大多数论文发表量较多的国家/机构在全球合著网络中都处于较为核心的地位。其中,美国、英国位列第一梯队。此外,部分国家/机构的表现,无论是在论文产出质量上还是在合作网络中的地位上,均与其论文产出规模的表现存在差异性。     

阻燃剂研究的文献计量分析

利用ISI Web of Science的数据,采用文献计量法,对世界范围内的阻燃剂(FR)科研产出进行分析。重点分析了2005~2015年FR领域的文献数量和增长趋势、高被引论文、论文高产国家/地区分布、重要科研机构、核心作者分布、学科领域分布、相关期刊及其影响因子和论文关键词等。文献分析结果表明,世界FR研究发展相对平稳。中国和美国在FR研究领域发文量方面处于世界领先地位,两国被SCI收录的相关论文超过世界论文总数的1/2。另外,中国科学院和中国科技大学发表FR相关论文总数也位居世界首列,但从论文质量和综合影响力来看,我国在FR领域和欧美发达国家依然存在差距。     

从文献计量看世界纳火研究的发展状况

依据SCI1996-2000年的纳米科技论文数据，统计和分析了世界各国纳米论文发表及合作研究情况；提出了纳米论文高产的世界高校、研究和企业前50名；纳米论文的国际期刊分布；对我国的纳米研究状况与世界部分国家（地区）的情况进行了对比分析。     

日本基础研究领域国际合作态势的文献计量分析

本文以科学引文索引数据库扩展版收录的、日本发表于2004～2008年的国际合著论文为研究对象，通过对论文在学科领域分布、国家分布、机构分布等方面的文献计量分析，揭示了过去5年来日本在基础研究领域所开展的国际合作的基本表现与特征。     

森林生态学研究态势计量分析

近年来,随着生态环境问题日益严峻,各国和各相关研究机构对森林生态学的研究力度不断加大。利用Thomson Data Analyzer(TDA)等文献计量分析工具,对2004~2014年SCIE收录的森林生态学研究相关文献进行了分析,讨论了相关研究领域不同国家、地区、主要研究机构的论文发文情况以及近年来国际森林生态学研究的状态和发展趋势。     

国际生物科学十年发展态势的文献计量分析(1992-2001年)

本文利用文献计量数据库，定量描述全球生物科学领域论文产出的学科分布、国家分布、机构分布及著者分布、时空分布、主要国家生物科学研究科学影响力的对比、中国生物学论文的状况、中国生物学领域顶尖论文数量占全球的比例，从而定量反映国际及中国生物科学的发展态势。     

基于文献计量的人脸识别技术研究进展与趋势分析

基于1991年以来全球人脸识别领域的研究论文和专利数据,对人脸识别技术的时间发展趋势、被引频次、产出国、研究机构等进行分析,并绘制引文编年图对演化路径进行解读。研究表明:中国和美国是目前世界上人脸识别研究领域综合实力最强的两个国家。美国在人脸识别的历史发展中起到了关键性作用;中国人脸识别研究整体水平已经进入世界先进行列,但整体学术影响力和科研质量有待进一步提高。从演化路径来看,人脸识别的技术演进经过了传统算法和深度学习算法两个阶段,后者是目前的主流算法。未来,提高在非理想环境下的人脸辨识度将是人脸识别研究的重点。     

基于文献计量的凝聚态物理理论重要研究机构分析

凝聚态物理学是物理学一个较大的分支学科,被美国、欧盟、英国作为发展量子信息科学、数字技术、磁性材料的重要基础学科之一。凝聚态物理在高温超导、拓扑物态领域取得了重要进展。文章将聚焦凝聚态物理理论研究方向,基于论文的学术影响力遴选出4个重要的机构,从机构组织结构和产出能力基本情况、机构的合作模式、资助机构、机构学术影响力4个维度分析,由点及面,反映我国在凝聚态物理理论研究领域的学术能力,并以此为基础,对我国在该领域需要提升的方面提出建议。建议我国围绕现有凝聚态物理理论领域的优势成果,拓展研究的深度和广度。基于凝聚态物理理论研究在量子信息科学等领域的重要作用,推动军事资助机构在凝聚态物理理论研究领域的投资。在提升核心科学家能力的基础之上,继续壮大发展研究队伍。继续拓宽国际合作的范围,争取能和更多国家、更多世界著名院校机构开展交流、合作。     

基于论文和专利分析的人工智能发展态势研究

为揭示当前人工智能领域的发展态势,本文统计分析了当前各主要国家/地区出台的顶层政策规划,并重点分析了人工智能领域论文和专利的年度变化、国家分布、主要机构、技术主题、方向对比和国际合作等。结果显示:当前人工智能科技成果产出正处于快速发展阶段,中美两国引领了人工智能领域科研成果;中国在该领域发文量接近美国,专利数量已超过美国;中国科研机构已具备开展国际竞争的能力,但市场主体的成果产出与先进国家尚有差距,国际化布局程度较低;如何提升机器的"认知能力"是当前人工智能研究的关注焦点。最后,基于分析,提出了对中国人工智能发展的启示。     

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.     

Phytotoxins as potential herbicides

Phytotoxins are produced in various culture media by many fungi that are pathogenic to weeds. These phytotoxins belong to a wide array of chemical substances including sesquiterpenoids, sesterterpenoids, diketopiperazines, peptides, spirocyclic lactams, isocoumarins, and polyketides. In most cases, the phytotoxin belongs to a family of related compounds produced by the fungus. These related compounds may or may not be phytotoxins. Phytotoxin production, in some cases, is optimized by the addition of a host extract to the culture medium. Biological activity is usually observed in a range of concentrations from 10^–3 to 10^–6 M. The concept of using these molecules, derivatives thereof, or related compounds as herbicides should be explored.     

Transfer of secondary metabolites from the spongesDysidea fragilis andPleraplysilla spinifera to the mantle dermal formations (MDFs) of the mudibranchHypserlodoris webbi

The opisthobranch molluscHypselodoris webbi is able to select, among its potential preys, sponges chemically rich in furanosesquiterpenoids. The sequestered secondary metabolites act as defensive allomones against predators and are accumulated in some dorsal glands (MDFs). This transfer from sponges to MDFs has been proven by maintainingH. webbi together with some selected sponges in an aquarium for a prolonged period.     

Instar-specific defensive secretions of stink bugs (Heteroptera: Pentatomidae)

Defensive secretions (allomones) from first-instar nymphs of stink bugs in the subfamily Pentatominae contain (E)-4-oxo-2-decenal as a major constituent, whereas this compound is absent from later instars. In contrast, first instars ofEdessa meditabunda (Edessinae) produce allomones like those of later instars. The C₆ and C₈ (E)-4-oxo-2-alkenals are common, characteristic exocrine compounds of nymphal and adult Heteroptera, but (E)-4-oxo-2-decenal is previously unknown as a major natural product for which a biological role has yet to be established.     

Structure and function of the fig

Summary An overview is given of the functional anatomy of the fig. The fig is the site of pollination and oviposition, it produces wasps, seeds and pollen, and it is the unit of dispersal. Therefore the fig acts as both a flower and a fruit. When a flower is both fertilized and receives a wasp egg, it eventually produces a wasp. Fertilization in flowers that do not recieve a wasp egg initiates seed production. Wide variation exists in the structural features of figs among different subgenera and sections. Monoecious species and gynodioecious species have different strategies for maintaining the symbiosis with the pollinating fig wasps. Monoecious species produce wasps and seeds in a single fig type and show imperfect heterostyly. Gynodioecious species have specialized figs for wasp and for seed production and are characterized by perfect heterostyly.     

Progress in molecular parasitology

Summary Substantial progress has been made in the last ten years in understanding the structural and functional organization of parasitic protozoa and helminths and the complex physiological relationships that exist between these organisms and their hosts. By employing the new powerful techniques of biochemistry, molecular biology and immunology the genomic organization in parasites, the molecular basis of parasite's variation in surface antigens and the biosynthesis, processing, transport and membrane anchoring of these and other surface proteins were extensively investigated. Significant advances have also been made in our knowledge of the specific and often peculiar strategies of intermediary metabolism, cell compartmentation, the role of oxygen for parasites and the mechanisms of antiparasitic drug action. Further major fields of interest are currently the complex processes which enables parasites to evade the host's immune defense system and other mechanisms which have resulted in the specific adaptations which enabled parasites to survive within their host environments. Various approaches in molecular and biochemical parasitology and in immunoparasitology have been proven to be of high potential for serodiagnosis, immunoprophylaxis and drug design.This paper is based on a review presented at a workshop on Molecular Parasitology, organized by the Swiss Society of Tropical Medecine and Parasitology at the University of Neuchâtel, March 1985.     

Ecological and evolutionary dynamics of fig communities

Summary I review the status of five topics in fig research: pollen-vector versus seed production, flowering phenology and wasp population dynamics, monoecy versus dioecy, parasite pressure, and fig wasp behavior. I raise several new questions based on recent research on two components of fig reproduction: pollen-donation (male) and seed-production (female) success. I focus on how these two components of reproductive success depend on the flowering phenology of the figs and the population dynamics of the pollinator wasps.     

Actin-, myosin- and ubiquitin-dependent endocytosis

Endocytosis is a general term that is used to describe the internalization of external and plasma membrane molecules into the cell interior. In fact, several different mechanisms exist for the internalization step of this process. In this review we emphasize the work on the actin-dependent pathways, in particular in the yeastSaccharomyces cerevisiae, because several components of the molecular machinery are identified. In this yeast, the analysis of endocytosis in various mutants reveals a requirement for actin, calmodulin, a type I myosin, as well as a number of other proteins that affect actin dynamics. Some of these proteins have homology to proteins in animal cells that are believed to be involved in endocytosis. In addition, the demonstration that ubiquitination of some cell surface molecules is required for their efficient internalization is described. We compare the actin, myosin and ubiquitin requirements for endocytosis with recent results found studying these processes usingDictyostelium discoideum and animal cells.     

Fluorinated analogs of insect sex pheromones

Summary The syntheses of fluorinated mimics of pheromones ofSpodoptera littoralis, Diparopsis castanea, Laspeyresia pomonella, Bombyx mori andThaumetopoea pityocampa are described. These analogs showed biological activities similar to those of the natural pheromones in laboratory assays (EAG).We gratefully acknowledge Comisión Asesora de Investigación Cientifica y Técnica for financial support (Grant No. 3296/79) and Consejo Superior de Investigaciones Cientificas for predoctoral and postdoctoral fellowship (to G.F. and M.R.). We also thank Mr J. Baltá and Ms R. Murgó for their collaboration in the EAG work.     

Complement evasion by the Lyme disease spirocheteBorrelia burgdorferi grown in host-derived tissue co-cultures: role of fibronectin in complement-resistance

The effectiveness of complement-mediated killing ofBorrelia burgdorferi, the causative agent of Lyme disease, in the presence of host-derived tissues was studied. Second and high passage forms ofB. burgdorferi 297 isolate were grown in a LEW/N rat joint tissue co-culture system and in artificial BSK medium. Guinea pig complement and third week immune serum from hamsters with experimental Lyme disease were added to the cultures. Both high and low passage borrelia grown in BSK medium died and did not revive after 3 weeks incubation in BSK medium. However, 5–12% of tissue co-cultured borrelia survived the first complement-mediated lysis. Repeated re-growth and lysis cycles in tissue co-culture resulted in isolation of an 85% complement-resistant population ofB. burgdorferi. Joint tissue culture supernatant collected on the third day of tissue culture, and fibronectin (25 g/ml), also protected spirochetes from complement-mediated lysis in contrast to BSK or fresh co-culture medium. Complement-mediated lysis may not be an effective mechanism in eradication of borrelia, and the chronicity of Lyme disease may be due to resistance ofB. burgdorferi variants to host immune defense mechanisms in the presence of host-derived tissues.