1,720,969 research outputs found
The interaction of DNMT1 and DNMT3A epigenetic enzymes with phthalates and perfluoroalkyl substances: an in silico approach
No full textThe occurrence of long-lasting adverse effects of the environmental contaminants on human health is a current emerging issue. In particular, phthalates, poly- and perfluoroalkyl substances are proposed to trigger toxic effects as well as persistent changes on human development and metabolism by different mechanisms, including epigenetic modifications, although the specific underlying pathways are still unknown. This study contributes to identify the potential molecular initiating events of epigenetic-mediated adverse effects by an in silico approach, which combines molecular docking and molecular dynamics simulation. The approach probes the potential molecular interaction between several different phthalates and persistent organic pollutants and a specific class of epigenetic modulators, namely the DNA methyltransferases (DNMTs). The dynamics of interaction and the binding free energies of the ligand-DNMTs complexes demonstrated that pollutants can be classified into two main groups, according to the ligand-target complex stability: (1) a larger class of phthalates (DBP, DEHP, MBP and MEHP) acting as inhibitors of the enzymatic activity of the epigenetic targets and (2) a smaller class of phthalates (DMP and MMP) and perfluoroalkyl substances (PFOA and PFOS) which do not interact stably with the human DNMTs. These findings provide the first valuable in silico insights on the ability of these specific environmental pollutants to directly bind and inhibit a key class of epigenetic regulators
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
A microdosimetric study of electropulsation on multiple realistically shaped cells. Effect of Neighbours
No full textOver the past decades, the effects of ultrashort-pulsed electric fields have been used to investigate their action in many medical applications (e.g. cancer, gene electrotransfer, drug delivery, electrofusion). Promising aspects of these pulses has led to several in vitro and in vivo experiments to clarify their action. Since the basic mechanisms of these pulses have not yet been fully clarified, scientific interest has focused on the development of numerical models at different levels of complexity: atomic (molecular dynamic simulations), microscopic (microdosimetry) and macroscopic (dosimetry). The aim of this work is to demonstrate that, in order to predict results at the cellular level, an accurate microdosimetry model is needed using a realistic cell shape, and with their position and packaging (cell density) characterised inside the medium
Diet and Epigenetics: Dietary Effects on DNA Methylation, Histone Remodeling and mRNA Stability
No full textEpigenetics relies on three major molecular mechanisms: DNA methylation, chromatin remodeling and RNA interference. Promoter hypermethylation usually drives gene silencing, whereas hypomethylation is associated with transcriptional activation. Chromatin remodeling is triggered by multiple post-translational modifications of histones that regulate the accessibility of genes to the transcription machinery. Non-coding RNAs, including microRNAs, modulate gene expression by altering the stability of target mRNAs. All these mechanisms can be modulated by nutrition. This contribution deals with the effect of either specific dietary profiles or specific molecules of nutritional interest on the above-mentioned epigenetic mechanisms and the potential consequences on human health and disease
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
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