1,721,844 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
Nuclear entry and export of FIH are mediated by HIF1α and exportin1, respectively
Full text linkHypoxia plays a critical role at cellular and physiological levels in all animals. The responses to chronic hypoxia are, at least substantially, orchestrated by activation of the hypoxia inducible transcription factors (HIFs), whose stability and subsequent transcriptional activation are regulated the by HIF hydroxylases. Factor inhibiting HIF (FIH), initially isolated as a HIFα interacting protein following a yeast two-hybridscreen, is an asparaginyl hydroxylase that negatively regulates transcriptionalactivation by HIF. This study aimed to define mechanisms that govern transitions of FIH between nucleus and the cytoplasm. We report that FIH accumulates in thenucleus within a short time window upon hypoxia treatment. We provide evidence, based on the application of genetic interventions and small molecule inhibition of the HIF hydroxylases, that the nuclear localization of FIH is governed by two opposing processes: nuclear entry by “coupling” with HIF1α for importin β1-mediated nuclear import and active export via a Leptomycin B-sensitive exportin1-dependent pathway
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
Mechanistic studies on histone demethylases and related enzymes
Full text linkHistone lysyl demethylases (2OG demethylases) are a family of nuclear proteins that catalyse the demethyation of Nε-methylated lysines on histone tails. 2OG demethylases belong to the 2-oxoglutarate and Fe(II) dependent dioxygenase superfamily, which utilise molecular oxygen to oxidise a wide variety of cellular substrates. The methylation states of histone lysines play crucial roles in regulating gene transcription, and consequently, the 2OG demethylases have been identified as important regulators of chromatin. Therefore, the understanding of the mechanisms and cellular activities of the demethylases is of considerable interest in the context of chromatin biology, and also for medicinal chemistry. Work in this thesis has focused upon investigating the mechanisms and reactivities of 2OG demethylases in vitro. NMR spectroscopy techniques were used to monitor demethylation catalysed by the 2OG demethylase JMJD2E, which resulted in the acquisition of kinetic parameters. Also, the use of a 13C-labelled substrate during NMR analysis enabled the first direct detection of enzymatically-produced formaldehyde. Studies with methylated lysine analogues using mass spectrometry and NMR methods revealed that many 2OG demethylases are capable of oxidising multiple substrates. One such substrate, Nε-methylisopropyllysine, was found to be hydroxylated by JMJD2E, providing strong evidence that 2OG demethylase-catalysed lysyl demethylation proceeds via hydroxylation. Studies with the lysine analogues prompted investigations with methylated arginine peptides; unexpectedly, three 2OG demethylases were observed to demethylate methylated arginines in both histone peptide variants and at known methylarginine sites in histone peptides. These findings indicate that 2OG demethyases may have diversified functions in cells, and are capable of accepting substrates besides methylated lysines. Investigations with point-substituted variants of the 2OG demethylase JMJD2A revealed new insights into the role of lysine-241 during catalysis. Specifically, the proposed role of lysine-241 in oxygen binding was discredited, with evidence suggesting that lysine-241 is likely to be involved in binding the substrate in the active site. Mass spectrometry experiments with the 2OG demethylase FBXL11 identified hydrolysis of histone peptides during incubation with the protein. Further analyses using mass spectrometry revealed that a metalloprotease was the likely catalyst for histone cleavage, indicating that optimised expression and purification of FBXL11 is required for quantitative assays. Studies with deuterated methyllysine substrates revealed a small kinetic isotope effect during 2OG demethylase-catalysed demethylation, indicating that the hydroxylation step during catalysis is partially rate determining. Finally, work was concentrated on investigating the potential metabolism of formaldehyde released during histone demethylation. NMR studies were conducted monitoring the non-enzymatic reaction of glutathione and formaldehyde; these revealed two novel adduct species that may be formed in cellular environments. The function and mechanism of a putative formaldehyde activating enzyme (GFA) was then investigated. These studies showed a limited effect of GFA upon formaldehyde reactivity, suggesting that GFA is not involved in formaldehyde metabolism. In summary, this work has revealed many new insights into both the substrate specificities and catalytic mechanisms of 2OG demethylases and has provided extensive studies probing potential formaldehyde metabolism. These investigations should form the basis of many new research areas on 2OG demethylases and related enzymes
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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