1,721,046 research outputs found
Structure Activity Relationships of the Ficin Hydrolysis of X-Phenyl Hippurates. Comparison with Papain, Actinidin and Bromelain
No full textQuantitative Structure Activity Relationships of Cysteine Hydrolases. Ficin Hydrolysis of X-Phenyl-N-Methanesulphonyl Glycinates
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A comparative QSAR analysis of acetylcholinesterase inhibitors currently studied for the treatment of Alzheimer's disease
No full textConsidering the relevance of acetylcholinesterase inhibitors as potential agents for the treatment of the Alzheimer's disease, we have undertaken a comparative QSAR analysis aimed at individuating the physico-chemical properties governing the inhibitory activity of such compounds. The QSAR equations for 13 series of derivatives have been calculated and discussed. The series studied are all those we found in the literature suitable for a QSAR analysis and represent the three main classes of acetylcholinesterase inhibitors currently investigated, namely, physostigmine analogues, 1,2,3,4-tetrahydroacridines and benzylamines. The equations we obtained show that, within each class, the main physico-chemical properties affecting the inhibitory activity are almost the same for all the series and can be individuated by the use of proper parameters. The conclusions of this study can be summarized as follows: (a) hydrophobicity plays a critical role in both the physostigmine-and the benzylamine-derived classes; (b) electronic effects are important for the interactions carried out by the variable portion of benzylamine derivatives; and (c) steric factors are also significant, but, as in other cases, the collinearity between steric and hydrophobic parameters does not allow one to draw any final conclusion
Actinidin hydrolysis of substituted-phenyl hippurates: a quantitative structure-activity relationship and graphics comparison with hydrolysis by papain
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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
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
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
Quantitative structure-activity relationships and molecular graphics in ligand receptor interactions: Amidine inhibition of trypsin
No full textQuantitative structure-activity relationships have been formulated for four sets of amidine inhibitors of trypsin. The quantitative results from these equations are compared with qualitative models constructed from the X-ray crystallographic coordinates of a benzamidine bound to trypsin. The good agreement between the mathematical and graphics models provides further support for the use of substituent constants and regression analysis in the study of enzyme-ligand interactions
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