1,720,956 research outputs found
Lipopeptides as anti-infectives: a practical perspective
No full textLipopeptide antibiotics represent an old class of antibiotics that were discovered over 50 years ago, which includes the old polymyxins but also new entries, such as the recently approved daptomycin. They generally consist of a hydrophilic cyclic peptide portion attached to a fatty acid chain which facilitates insertion into the lipid bilayer of bacterial membranes. This review presents an overview of this class of antibiotics, focusing on their therapeutic applications and putting particular emphasis on chemical modifications introduced to improve their activit
Atomic force microscopy evaluation of the effects of a novel antimicrobial multimeric peptide on Pseudomonas aeruginosa.
No full textSynthesis, characterization, antimicrobial activity and LPS-interaction properties of SB041, a novel dendrimeric peptide with antimicrobial properties
No full textMultimeric peptides offer several advantages with respect to their monomeric counterparts, as increased
activity and greater stability to peptidases and proteases. SB041 is a novel antimicrobial peptide with dendrimeric
structure; it is a tetramer of pyrEKKIRVRLSA linked by a lysine core, with an amino valeric acid
chain. Here, we report on its synthesis, NMR characterization, antimicrobial activity, and LPS-interaction
properties. The peptide was especially active against Gram-negative strains, with a potency comparable
(on molar basis) to that of lipopeptides colistin and polymixin B, but it also displayed some activity against
selected Gram-positive strains. Following these indications,weinvestigated the efficacy of SB041 in binding
Escherichia coli and Pseudomonas aeruginosa LPS in vitro and counteracting its biological effects in
RAW-BlueTM cells, derived from RAW 264.7 macrophages. SB041 strongly bound purified LPS, especially
that of E. coli, as proved by fluorescent displacement assay, and readily penetrated into LPS monolayers.
However, the killing activity of SB041 against E. coli was not inhibited by increasing concentrations
of LPS added to the medium. Checking the SB041 effect on LPS-induced activation of pattern recognition
receptors (PRRs) in Raw-Blue cells revealed that while the peptide gave a statistically significant
decrease in PRRs stimulation when RAW-Blue cells were challenged with P. aeruginosa LPS, the same was
not seen when E. coli LPS was used to activate innate immune defense-like responses. Thus, as previously
seen for other antimicrobial peptides, also for SB041 binding to LPS did not translate necessarily into
LPS-neutralizing activity, suggesting that SB041–LPS interactions must be of complex natur
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
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