1,720,955 research outputs found
Fatty acids acutely enhance insulin-induced oxidative stress and cause insulin resistance by increasing mitochondrial reactive oxygen species (ROS) generation and nuclear factor-κB inhibitor (IκB)-nuclear factor-κB (NFκB) activation in rat muscle, in the absence of mitochondrial dysfunction.
No full textAIMS/HYPOTHESIS:
Insulin effects reportedly involve reactive oxygen species (ROS) and oxidative stress in vitro, but skeletal muscle oxidative stress is an emerging negative regulator of insulin action following high-fat feeding. NEFA may enhance oxidative stress and insulin resistance. We investigated the acute impact of insulin with or without NEFA elevation on muscle ROS generation and insulin signalling, and the potential association with altered muscle mitochondrial function.
METHODS:
We used hyperinsulinaemic-euglycaemic clamping, 150 min, without or with lipid infusion to modulate plasma NEFA concentration in lean rats.
RESULTS:
Insulin and glucose (Ins) infusion selectively enhanced xanthine oxidase-dependent muscle ROS generation. Ins with lipid infusion (Ins+NEFA) lowered whole-body glucose disposal and muscle insulin signalling, and these effects were associated with high muscle mitochondrial ROS generation and activation of the proinflammatory nuclear factor-κB inhibitor (IκB)-nuclear factor-κB (NFκB) pathway. Antioxidant infusion prevented NEFA-induced systemic insulin resistance and changes in muscle mitochondrial ROS generation, IκB-NFκB pathway and insulin signalling. Changes in insulin sensitivity and signalling were independent of changes in mitochondrial enzyme activity and ATP production, which, in turn, were not impaired by changes in ROS generation under any condition.
CONCLUSIONS/INTERPRETATION:
Acute muscle insulin effects include enhanced ROS generation through xanthine oxidase. Additional NEFA elevation enhances mitochondrial ROS generation, activates IκB-NFκB and reduces insulin signalling. These alterations are not associated with acute reductions in mitochondrial enzyme activity and ATP production, and are reversed by antioxidant infusion. Thus, NEFA acutely cause systemic and muscle insulin resistance by enhancing muscle oxidative stress through mitochondrial ROS generation and IκB-NFκB activation
Can the interaction between the antimicrobial peptide LL-37 and alginate be exploited for the formulation of new biomaterials with antimicrobial properties?
No full textIn this study, we took advantage of the strong interaction between the antimicrobialpeptideLL-37 and anionic polysaccharides, such as alginate, to design and evaluate a new biomaterial with putative antibacterial properties.
To begin with, we have investigated the effect of different biocompatible polysaccharides on both the cytotoxicity and the antimicrobial activity of LL-37, a powerful endogenous antimicrobialpeptide of human origin, whose use in therapy has been hampered by its toxicity to host cells. Interactions of the peptide with polysaccharides were evaluated by circular dichroism analyses, which revealed a different capacity of the polymers to induce the active helical conformation in the peptide. Among the polysaccharides tested, sodium alginate was the only one that significantly reduced the toxicity of LL-37 toward mammalian cells. A sodium alginate/LL-37 preparation was then tested on four bacterial strains. The Gram-negative bacteria resulted susceptible to the mixture, while the growth of the Gram-positive ones was poorly affected and only at the highest peptide concentration tested. Following the positive results with Gram-negative species, the alginate/LL-37 binary system was used for the preparation of calcium alginate beads, which were tested for peptide release
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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