1,720,974 research outputs found
Tunichrome mimetic matrix, its perspective in abatement for carcinogenic hexavalent chromium and specific coordination behavior
No full textInspired by naturally occurring metal chelation strategy by pyrogallol moiety of tunichromes of marine tunicates, a strong retention of carcinogenic chromium (Cr-VI) is described by mimicking tunichrome matrix as a proof-of-concept investigation in water treatment applications. Harvesting tunichromes tailored with the pyrogallol moiety are extremely difficult owing to aerial sensitivity and purification difficulties, thus proving a challenging synthesis problem. Despite significant interest, knowledge of specific metal coordination in tunicate's matrix is still ambiguous, hindering study scope. We planned to fabricate a promising tunichrome matrix (TM) tailored with pyrogallol moieties from the Earth-abundant raw materials (gallic acid and chitin nanofiber) at mass scale without artificial aid. Specifically, we aimed at atomistic understanding of contaminant and pyrogallol moiety of TM by examining the structural parameters (redox change, geometrical distortion, coordination bond). Cr K-edge extended X-ray absorption fine structure (EXAFS) corresponds well to nontoxic Cr-III (average four Cr-O bond lengths of 1.91 angstrom) and a small fraction of Cr-VI (average two Cr-O bond lengths of 1.62 angstrom). A coupled reductive complexation mechanism was identified by combining near edge X-ray absorption fine structure (NEXAFS) and linear combination fits. From the viewpoint of practical utility and effective performance (nearly 119 mg chromium per g weight of TM), the impacts of water chemistry conditions were investigated from a variety of contaminated waters, showing a distinct improvement compared to conventional popular materials. The gained knowledge would be beneficial for utilizing a pyrogallol moiety as an alternative greener and sustainable scavenger, specifically for toxic chromium. (C) 2017 Elsevier B.V. All rights reserved.112sciescopu
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
Tunicate-Inspired Gallic Acid-Conjugated Chitin Nanofibrous Matrix for Metal Sequestration and Water Treatment Applications
No full textMasterTunicate, marine filter feeder, exhibit an outstanding metal sequestration ability on their blood cells through a series of complexation reaction with oligopeptide containing 3,4,5-trihydroxyphenilalanin (TOPA) moieties called tunichrome. Inspired by this naturally occurred strategy, we design a nano-bio filtration matrix mimicking tunichrome using two cheap and abundant precursor; pyrogallol-5-carboxylic acid (gallic acid) and chitin nanofiber, which is the chitin nanofibrous matrix tailored with gallic acids (CGa). The tunicate mimetic matrix (CGa) demonstrated the versatility of strategy in the generation of water filtration material, especially for 1) gold recovery and 2) carcinogenic hexavalent chromium removal. CGA showed unprecedented fine and clean gold recovery (>99%, 533 mg gold per gram weight), which exceeds that of the present most popular materials. Extended X-ray absorption fine structure (EXAFS) spectroscopy and data-fitting elucidated the decreased coordination numbers for Au-Au nearest neighbors, demonstrating gold coordinated to pyrogallol units, followed by an intramolecular association of Au0. A catalytic reduction of 4-nitrophenol mediated by the CGa with harvested gold revealed an excellent recyclability up to 30 cycles (~95% reduction), together with methylene blue reduction and antimicrobial performances, indicating a versatile characteristic of sustainable processes by the CGa.
In addition, the CGa also exhibits a superior performance towards carcinogenic hexavalent chromium removal (nearly 119 mg chromium per g weight of CGa). Cr K-edge extended X-ray absorption fine structure (EXAFS) corresponds well to nontoxic CrIII (average four Cr-O bond lengths of 1.91 Å) and a small fraction of CrVI (average two Cr-O bond lengths of 1.62 Å). A coupled reductive complexation mechanism was identified by combining near edge X-ray absorption fine structure (NEXAFS) and linear combination fits. This strategy opens the door for fast-developing new biomimetic alternatives for metal sequestration which is not restricted to gold and chromium and can offer a tool for multifaceted soft/hard nanomaterials
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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