1,721,088 research outputs found
Novel methodologies in quantitative proteomics
No full textThe proteome is defined as the set of all expressed proteins in a cell, tissue or organism. Proteome analysis presents specialized analytical problems in two major areas: i) dynamic expression range and ii) diversity of protein expression (multiple protein forms).
Post-translational modification of proteins is part of what makes proteomics so much challenging. It is an event with dramatic effects on the complexity of the proteome. Nowadays the attention towards PTMs is notably increased due to the fact that they play a critical role in cellular functioning and they vary in response of environmental
stimuli. There are many classical techniques designed to analyse PTMs. This PhD thesis focuses on the development of new proteomics approaches for qualitative and quantitative analysis of protein nitration, protein carbonylation and
protein phosphorylation, three of the most important known PTMs. The approaches are mainly based on selective chemical modification of residues of interest coupled to advanced mass spectrometry methods. These approaches aim at a comprehensive analysing of such modifications by identification of the modified proteins, exact localization of the modified residues and quantification of the modification.
The first section of this thesis is focused on the development and the optimization of a new strategy for the qualitative and quantitative analysis of nitration of tyrosine residues. Thus, improved approach, based on chemical labelling and mass spectrometric procedures, for the selective analysis of 3-nitrotyrosine residues in
protein mixtures is described. However the major aim of this work is devoted to the use of isotopically labelled molecule to allow a simple and direct quantitative MS
analysis.
The second part aims to the optimization of a labelling protocol of carbonylated residues coupled to advanced mass spectrometry based scanning techniques to improve detection of such residues. Moreover a method for selective quantitative analysis is also described, aimed at the direct quantification of oxidation levels of proteins in different samples.
The last part of the work is focused on the development of a strategy for qualitative and quantitative analysis of serine and threonine phosphorylation without preliminary
enrichment but using chemical labelling in combination with the high performance of a novel hybrid mass spectrometer Linear Ion Trap.
To prove their wide enforceability these methodologies were set up first on model proteins and then applied to more complex systems
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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