Jean-François Miquel

Structure of International Collaboration in Science : Typology of countries through multivariate techniques using a link indicator

In this article patterns of international collaboration in science are investigated using a specific procedure to analyse data collected from theScience Citation Index. We develop an indicator based on the scientific linkages between countries established through internationally co-authored articles (COPs). The credibility, advantages and uses of this indicator are discussed. We apply the Correspondence Factorial Analysis method and the Minimum Spanning Tree classification to this indicator in order to observe the level of resemblance and the main characteristics of the collaboration structured by 98 countries in eight principal fields of science. The results shown summarize the diverse aspects of countries participating in collaborative works and bring into view the cognitive structure of international research. The use of these methods in the investigation of international collaboration contributes to the analysis of the complex structure of the scientific communities of different countries.

Structure of international collaboration in science-part II: Comparisons of profiles in countries using a link indicator

In this article, the behaviors of countries in scientific production activities are investigated using an asymmetrical matrix system to analyze data collected from theScience Citation Index. Examination of international collaboration, intercountry relationships, and domestic scientific output patterns structured by 98 countries in eight principal fields of science reveal diverse aspects of country behaviors. Three asymmetrical matrixes are established and the multidimentional Minimum Spanning Tree technique is applied to classify, visualize and determine the distinctive characteristics of country profiles. Investigations are conducted at both a macro (country behavior) and a micro (particular city behavior) level in order to demonstrate the applicability of the methodology and to obtain global observations of country behaviors. It is argued that these methods contribute to reveal traditions and policies of countries, universities and research organizations as well as that of the international network of scientific exchange. Further usage of these methodologies is advocated for policy analysis.

International scientific collaboration in Latin America

This study attempts to analyse the usability of international databases such as the Science Citation Index (SCI) for the observation of the international collaboration in lesser-developed countries. We have examined the adequacy of this data source (the SCI) in perceiving the international scientific activities of nine Latin American countries. We have studied the relationships of these countries with their main foreign partners in the large fields of science. It has been observed that some of these relationships are not covered by the data source under study. The creation of an information system storing complementary data suited for the identification of existing internatinal collaborative projects is recommended. In the longrange future such a system would provide more appropriate information for the analyses of international collaboration.

Influence of di- and tri-phenylethylene estrogen/antiestrogen structure on the mechanisms of protein kinase C inhibition and activation as revealed by a multivariate analysis

We have performed a systematic study of the interaction of 36 di- and tri-phenylethylene derivatives (DPEs and TPEs) with protein kinase C (PKC). The results were submitted to a multivariate analysis in order to identify the structural features that might be implicated in interference with the activity of three PKC subspecies under three enzyme activation conditions. Four groups of test-compounds, each with common chemical features, could be distinguished clearly. The first group comprised all TPEs substituted with at least one basic dialkylaminoethoxy side-chain. These inhibited type alpha, beta and gamma PKC subspecies activated by Ca2+ and phosphatidylserine (PS) with or without diolein (DO) at micromolar concentrations but did not inhibit protamine sulfate phosphorylation. The other effectors, which all possessed a 1,1-bis-(p-hydroxyphenyl) ethylene moiety, influenced PKC activity at high concentrations (30-200 microM) and could be divided into two groups. One group constituted PKC inhibitors in the TPE series and inhibited PKC activated by Ca2+, PS and DO, as well as protamine sulfate phosphorylation. The other group constituted dual-type inhibitors/activators in the DPE series and stimulated PKC in the presence of Ca2+ and low PS concentrations but inhibited the enzyme in the simultaneous presence of DO. The fourth group of compounds was inactive and had, for the most part, one or two substituents with weak steric hindrance. In agreement with previous data for six lead compounds, this study suggests that, in these chemical series, a basic amino side-chain leads to interaction with phospholipid and the regulatory domain of PKC, whereas a 1,1-bis-(p-hydroxyphenyl) ethylene moiety leads to interaction with the catalytic domain of the enzyme.

World science in 18 disciplinary areas: Comparative evaluation of the publication patterns of 48 countries over the period 1981–1992

In order to be able to develop indicators that can measure the scientific and technological productivity of a nation, it is helpful to have at ones command a prior purely descriptive global overview of how various nations stand with respect to each other with regard to world science, i.e., to dispose of a framework for the elaboration of future quantitative studies.ISI has recently made available a highly comprehensive multidisciplinary database (over 6 million bibliometric entries from 1981 to 1992) that is founded on top-echelon journals and that can form the basis of such a framework. We have in the present study defined a publication pattern per nation that reflects its interest and potential in 18 disciplines and compared the publication patterns of 48 nations by descriptive multivariate analysis, i.e., by measuring the distance between nations in the n-dimensional system. Proximity is a sign of similarity, distance of diversity. Three multivariate methods of distance measurement were used: a hierarchical classification, the distance of each nation from the centre of gravity of the system calculated by χ2-metrics (typicality of behaviour), a bi-plot of the χ2-distances of 46 countries with respect to two reference countries that highlights clusters of nations with similar behaviour.The resultant plots are open to interpretation by experts. We conclude that three factors, geographical proximity, culture, and economic development are the principal determinants of the publication patterns of nations.

A chemical classification of nonsteroidal antagonists of sex-steroid hormone action

A highly varied collection of nonsteroids have been reported over the last forty years as being able to exert an antihormonal action versus steroid hormones in vivo. This diversity is partly explained by the manifold molecular targets of these compounds which may be either enzymes or receptors (leading to inhibition of steroid production and action respectively) and by the different possible levels of interference within feedback loops between the central nervous system, pituitary, gonads and other peripheral organs. The present chapter is a chemists classification of some of these structures often in the absence of detailed biochemical data. Nonsteroid antiestrogens (and estrogens) most often share a common feature with diethylstilbestrol and consequently the effects of structural modifications on biological activities can be studied in a rational manner. This is not the case for non-steroidal antiandrogens that we have only been able to classify into conventional chemical groups. Nor have any true lead compounds nor well-defined chemical classes been identified for nonsteroid antiprogestogens. This is however the only hormonal class where natural products play an important role.

International scientific collaboration in Arab countries

Through internationally coauthored scientific articles in the Science Citation Index data base, we analyse international collaboration of some Arab countries in science. Our findings show that international collaboration of these countries is concentrated on engineering & technology and fundamental & applied biology. Collaboration is often established through doctoral studies and the links thus created continue. Cultural and historical traditions play an important role in collaboration. We compare the SCI data base with a local survey of chemists in Morocco and discuss some of the limits of bibliometric methods.

Relative involvement of protein kinase C and of the estrogen receptor in the cytotoxic action of a population of triphenylethylenes on MCF7 cells as revealed by correspondence factorial (CF) analysis

A multivariate statistical method, correspondence factorial (CF) analysis, was used to examine the correlations among the protein binding and cell proliferation effects of a series of 36 di- and triphenylethylenes (DPEs and TPEs). The analysis was applied to a study which measured their competition for estradiol binding to cytosol estrogen receptor (ER), their influence on protein kinase C (PKC) activity under different conditions of enzyme activation, their ability to promote the growth of a breast cancer cell line and to inhibit growth at high concentrations (cytotoxicity). The CF analysis revealed several levels of correlation. First, it distinguished those molecules within the population that stimulated rather than inhibited PKC activity. Second, it made apparent a strong correlation between cytotoxicity and inhibition of Ca++ and phosphatidylserine-dependent PKC activity, which was most marked when the enzyme had been activated by diacylglycerol indicating that PKC inhibition under physiological conditions might contribute to the overall cytotoxicity of these compounds. Third, a lower level of correlation was established between competition for ER binding and cytotoxicity. Taken together, the results suggest that MCF7 cells might be most sensitive to a cytotoxic effect of TPEs (via PKC and other targets) when they at the same time decrease estrogen-stimulated proliferation via an ER-mediated antiestrogenic effect.

Dual action of hydroxylated diphenylethylene estrogens on protein kinase C

Protein kinase C (PKC) I (gamma), II (beta) and III (alpha) subspecies are all activated by 1,1-di-(p-hydroxyphenyl)ethylene derivatives (DPE) at micromolar concentrations. This PKC activation depends on the presence of both Ca2+ and phosphatidylserine (PS) but does not require diacylglycerol (DG). DPEs enhance PKC activity at low PS concentrations, but not at saturating PS concentrations. Like DG, DPEs increase the apparent affinity of PKC for PS as well as for Ca2+, but lead to a decrease in the catalytic activity (Vmax). In the presence of saturating DG concentrations, DPEs exhibit an inhibitory action. The derivatives also inhibit the activity of the proteolytic fragment of PKC, protein kinase M. It is concluded that DPEs are mixed-type inhibitors, probably interacting with the catalytic domain of the enzyme.

IDEAS: a system for international data exchange and access for science

Abstract An operational prototype inhomogeneous distributed database system has been built to provide homogeneous access for researchers and managers of science policy to data on research projects held in three countries. The architecture is sufficiently general not only to accommodate additional countries and databases on research projects, but also to provide a general framework for other international collaborative projects aimed at the provision of information. The design exhibits an optimal compromise between sufficient data to satisfy a retrieval request and the minimal data for transmission to maintain the database.