1,721,007 research outputs found
Electrochemical degradation of methylene blue
No full textThis study was performed to compare the direct and indirect electrochemical oxidation of a synthetic solution containing methylene blue. The direct electrolysis was carried out using boron-doped diamond, while the indirect electrolyses were mediated by active chlorine electrogenerated on a TiRuO2 oxide anode. The effects of the operating factors that influence COD and colour removal were investigated for each type of electrolysis in order to find the optimum conditions. The experimental results revealed the suitability of both electrochemical processes for completely removing the COD and effectively decolourising the solution. In particular, in the indirect electrolysis, the oxidation of methylene blue only occurred in the presence of chloride ions that acted as redox mediators and the reaction was affected by the chloride concentration and applied current density, while in the direct electrolysis the oxidation took place by reaction with electrogenerated hydroxyl radicals and was favoured by high flow rates, meaning that the oxidation was a diffusion-controlled process. The comparison of the results showed that faster mineralisation and decolourisation of the solution was achieved by the indirect electrolysis, due to the high bleaching properties of active chlorine
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
Electrochemical study of self-assembled cysteine monolayers on polycrystalline gold electrodes and functionalization with microperoxidase MP-11.
No full textSelf-assembled monolayers of cysteine (CYST) have been constructed on polycrystalline gold (polyAu) electrode at different immersion times (timmer) in order to characterize them by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Oxidative desorption experiments allowed the calculation of the surface coverage, whereas reductive desorption informed about the binding of CYST to different gold domains.
Desorption products showed different diffusion ability. The maximum coverage was already achieved at short timmer,
although progressive reordering of CYST molecules led to a relevant decrease of the defects at long time, as ascertained
by EIS. Functionalization of polyAu-CYST electrodes with the enzyme microperoxidase MP-11 performed by following two different binding methods showed that the enzymatically catalyzed reduction of H2O2 is enhanced when the –COOH residues of the MP-11 undecapeptide chain are firstly activated and then linked to the –NH2 functional groups of the non-activated CYST layer formed on the polyAu surface
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
Determination of hydroxyl free radical formation in human platelets using high-performance liquid chromatography with electrochemical detection.
No full textThe formation of the hydroxyl free radical (HFR) can be quantified indirectly, by measuring two products of the hydroxylation of salicylic acid, 2,3-dihydroxybenzoate (2,3-DHB) and 2,5-dihydroxybenzoate (2,5-DHB). In this study, we used reversed-phase high-performance liquid chromatography with electrochemical (coulometric) detection to measure 2,3- and 2,5-DHB levels in human platelets. The limits of detection of the method were 10 and 5 fmol on column for 2,3-DHB and 2,5-DHB, respectively. We tested the technique by measuring increases in dihydroxybenzoate levels after exposure of platelets to experimentally induced oxidative stress. Then, we measured platelet levels of 2,3- and 2,5-DHB in patients with Parkinson's disease, under therapy with L-DOPA, and in normal subjects. We also measured platelet concentrations of L-DOPA and its major metabolite, 3-O-methyldopa (3-OMD). Parkinsonian patients showed increased levels of both 2,3- and 2,5-DHB. Platelet levels of 2,3-DHB were positively correlated with platelet levels of L-DOPA and 3-OMD. The technique we describe proved simple and extremely sensitive and may represent a useful tool for the study of oxidative stress in humans. Copyright (C) 1999
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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