1,720,955 research outputs found
Novel CFTR Chloride Channel Activators Identified by Screening of Combinatorial Libraries Based on Flavone and Benzoquinolizinium Lead Compounds
No full textThe flavonoid genistein and the benzo[c]quinolizinium MPB-07 have been shown to activate the cystic fibrosis transmembrane conductance regulator (CFTR), the protein that is defective in cystic fibrosis. Lead-based combinatorial and parallel synthesis yielded 223 flavonoid, quinolizinium, and related heterocyclic compounds. The compounds were screened for their ability to activate CFTR at 50 microm concentration by measurement of the kinetics of iodide influx in Fisher rat thyroid cells expressing wild-type or G551D CFTR together with the green fluorescent protein-based halide indicator YFP-H148Q. Duplicate screenings revealed that 204 compounds did not significantly affect CFTR function. Compounds of the 7,8-benzoflavone class, which are structurally intermediate between flavones and benzo[c]quinoliziniums, were effective CFTR activators with the most potent being 2-(4-pyridinium)benzo[h]4H-chromen-4-one bisulfate (UCcf-029). Compounds of the novel structural class of fused pyrazolo heterocycles were also strong CFTR activators with the most potent being 3-(3-butynyl)-5-methoxy-1-phenylpyrazole-4-carbaldehyde (UCcf-180). A CFTR inhibitor was also identified. The active compounds did not induce iodide influx in null cells deficient in CFTR. Short-circuit current measurements showed that the CFTR activators identified by screening induced strong anion currents in the transfected cell monolayers grown on porous supports. Compared with genistein, the most active compounds had up to 10 times greater potency in activating wild-type and/or G551D-CFTR. The activators had low cellular toxicity and did not elevate cellular cAMP concentration or inhibit phosphatase activity, suggesting that CFTR activation may involve a direct interaction. These results establish an efficient screening procedure to identify CFTR activators and inhibitors and have identified 7,8-benzoflavones and pyrazolo derivatives as novel classes of CFTR activators
CFTR activation in human bronchial epithelial cells by novel benzoflavone and benzimidazolone compounds
No full textActivators of the CFTR Cl- channel may be useful for therapy of cystic fibrosis. Short-circuit current (Isc) measurements were done on human bronchial epithelial cells to characterize the best flavone and benzimidazolone CFTR activators identified by lead-based combinatorial synthesis and high-throughput screening. The 7,8-benzoflavone UCcf-029 was a potent activator of Cl- transport, with activating potency (5 to <0.4 microM with increasing basal Isc from approximately 4 microA/cm2 to approximately 12 microA/cm2. This dependence was confirmed in permeabilized Fischer rat thyroid cells stably expressing CFTR. Our results demonstrate efficacy of novel CFTR activators in bronchial epithelia and provide evidence that activating potency depends on basal CFTR activity
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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