1,721,197 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Reactions and enzymes in the metabolism of drugs and other xenobiotics
No full textIn this article, we offer an overview of the compared quantitative importance of biotransformation reactions in the metabolism of drugs and other xenobiotics, based on a meta-analysis of current research interests. Also, we assess the relative significance the enzyme (super)families or categories catalysing these reactions. We put the facts unveiled by the analysis into a drug discovery context and draw some implications. The results confirm the primary role of cytochrome P450-catalysed oxidations and UDP-glucuronosyl-catalysed glucuronidations, but they also document the marked significance of several other reactions. Thus, there is a need for several drug discovery scientists to better grasp the variety of drug metabolism reactions and enzymes and their consequences
Musings on ADME predictions and structure-activity relations
No full textThe first part of the paper examines Structure-Activity Relations (SARs) and their components from a very general point of view. The various types of interpretation emerging from statistically valid relations will be examined, namely causal (mechanistic), contextual (empirical), fortuitous, and tautological correlations. Implications for ADME predictions will be seen when discussing the diversity of interactions between active compounds (e.g., drugs) and biological systems. The second part of the paper is more specific and presents the concept of molecular-property space, an all but neglected concept in SARs. Recent results from Molecular Dynamics (MD) simulations and Molecular Interaction Fields (MIF) computations of acetylcholine will be used to illustrate not only the well-known conformational space of this molecule, but also its property space as exemplified by its lipophilicity space. It will be seen that a molecule as small as acetylcholine is able to span a relatively broad property space. Most significantly in an ADME perspective, the molecule is able, within the limits of its property space, to adapt to the medium. This is equivalent to saying that the medium constrains the molecule to resemble it as much as feasible
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Assessing drug-likeness : what are we missing?
No full textThe concept of drug-likeness helps to optimise pharmacokinetic and pharmaceutical properties, for example, solubility, chemical stability, bioavailability and distribution profile. A number of molecular descriptors have emerged as reasonably informative and predictive, for example, the Rule-of-Five. Here, we review some current approaches, then discuss their major shortcoming, namely the static nature of the structural features and physicochemical properties they encode. As we demonstrate, molecules are not ''frozen statues'' but ''dancing ballerinas'', and several of their computable physicochemical properties are conformation-dependent and lead to the concept of property spaces. Molecular sensitivity (namely, how much a given computable physicochemical property varies as a function of flexibility) appears as a promising descriptor to encode some of the information contained in molecular property space
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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