1,720,999 research outputs found
Aromatic interactions and rotational strengths within protein environment: An electronic structural study on β-lactamases from class A
No full textβ-Lactamases are important enzymes, responsible for bacterial resistance against β-lactam antibiotics. The enzymes from class A are the most common and the most intensively studied. Here we present our electronic structural study on the relationships between electrostatic interactions and chiroptical properties of three enzymes from class A in the following directions: (i) an integrated influence of environment and ionization state on the rotational strengths mechanisms of tyrosine chromophore in TEM-1 β-lactamase; (ii) an effect of electrostatic environment on the mechanisms of aromatic rotational strengths in β-lactamases from Streptomyces albus and Staphylococcus aureus
Relationship between chiroptical properties, structural changes and interactions in enzymes: A computational study on β-lactamases from class A
No full textEnzyme functions such as catalysis, binding and regulation are directly related to a variety of conformational changes. A sensitive and useful method for their investigation is circular dichroism (CD) and a rotational strength (R) is its fundamental characteristic. In this study, we show how the sensitivity of the mechanisms of rotational strengths to important conformational changes depends on the chromophore environment in two ß-lactamases from class A (from Escherichia coli and B. licheniformis). Rotational strengths have been calculated using the matrix method and including the effects of local environment (LE). X-ray structures (of protein components) of several enzyme–ligand complexes from the catalytic cycle of the TEM-1 enzyme and for both crystallographic monomers of the enzyme from B. licheniformis were used. An analysis of the relative degree of perturbation of the rotational strengths upon local interactions is performed
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
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
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
FDM analysis for squeezed flow of hybrid nanofluid in presence of Cattaneo-Christov (C-C) heat flux and convective boundary condition
No full textIn this paper we have computed squeezing channel flow of hybrid nanofluid (Al2O3+SiO2+ Water). The lower surface of the channel is subjected to stretching property. Upper surface moves (squeezes) towards lower surface. Heat transport is explored through Cattaneo-Christov (C-C) heat flux and convective boundary condition. This model is constructed via modification in Fourier’s law by addition of thermal relaxation time factor. The governing expressions (PDEs) are non-dimensionalized through suitable variables. The obtained non-dimensional systems (PDEs) are solved using FDM (finite difference method). Velocities, temperature and skin friction are graphically evaluated with respect to influential variables
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