1,720,974 research outputs found
PLP-dependent enzymes as potential drug targets for protozoan diseases
No full textThe chemical properties of the B(6) vitamers are uniquely suited for wide use as cofactors in essential reactions, such as decarboxylations and transaminations. This review addresses current efforts to explore vitamin B(6) dependent enzymatic reactions as drug targets. Several current targets are described that are found amongst these enzymes. The focus is set on diseases caused by protozoan parasites. Comparison across a range of these organisms allows insight into the distribution of potential targets, many of which may be of interest in the development of broad range anti-protozoan drugs. This article is part of a Special Issue entitled: Pyridoxal Phosphate Enzymology
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Structural and thermodynamic insights into the assembly of the heteromeric pyridoxal phosphate synthase from plasmodium falciparum
No full textPyridoxal 5'-phosphate (PLP) is required as a cofactor by many enzymes. The predominant de novo biosynthetic route is catalyzed by a heteromeric glutamine amidotransferase consisting of the synthase subunit Pdx1 and the glutaminase subunit Pdx2. Previously, Bacillus subtilis PLP synthase was studied by X-ray crystallography and complex assembly had been characterized by isothermal titration calorimetry. The fully assembled PLP synthase complex contains 12 individual Pdx1/Pdx2 glutamine amidotransferase heterodimers. These studies revealed the occurrence of an encounter complex that is tightened in the Michaelis complex when the substrate l-glutamine binds. In this study, we have characterized complex formation of PLP synthase from the malaria-causing human pathogen Plasmodium falciparum using isothermal titration calorimetry. The presence of l-glutamine increases the tightness of the interaction about 30-fold and alters the thermodynamic signature of complex formation. The thermodynamic data are integrated in a 3D homology model of P. falciparum PLP synthase. The negative experimental heat capacity (C(p)) describes a protein interface that is dominated by hydrophobic interactions. In the absence of l-glutamine, the experimental C(p) is less negative than in its presence, contrasting to the previously characterised bacterial PLP synthase. Thus, while the encounter complexes differ, the Michaelis complexes of plasmodial and bacterial systems have similar characteristics concerning the relative contribution of apolar/polar surface area. In addition, we have verified the role of the N-terminal region of PfPdx1 for complex formation. A "swap mutant" in which the complete alphaN-helix of plasmodial Pdx1 was exchanged with the corresponding segment from B. subtilis shows cross-binding to B. subtilis Pdx2. The swap mutant also partially elicits glutaminase activity in BsPdx2, demonstrating that formation of the protein complex interface via alphaN and catalytic activation of the glutaminase are linked processes
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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