1,720,956 research outputs found
Sviluppo e caratterizzazione di un nuovo microsensore per il monitoraggio in tempo reale della autossidazione della dopamina
Get PDFOxidative stress is responsible of the dopaminergic neuronal death at nigro-striatal level, as in Parkinson's Disease. Reactive oxygen species are responsible of the non enzymatic oxidation of dopamine (DA, so called auto-oxidation). Both, the non-enzymatic dopamine auto-oxidation and the enzymatic one, determine the formation of the corresponding ortho-quinone with the production of anion superoxide (O2-) and hydrogen peroxide (HP). In this study we have developed a novel electrochemical device able to monitor the auto-oxidation of DA, induced by HP, exploiting the different catalytic properties of the materials used as electrochemical transducers. The electrochemical cell consists in a buffer solution at pH 7.4, reproducing the cerebral extracellular environment, an Ag/AgCl pseudoreference electrode, an auxiliary electrode and two working electrodes, one made with epoxycarbon (Ep) and the other one with platinum (Pt). Ep sensors were coated with a poly-dopamine (pDA) permselective polymer, while Pt sensors were coated with poly-orthofenilendiamine (pPD). The developed system is able to record the redox interactions between DA and HP in a homogeneous phase and in the presence of interfering molecule such as ascorbic acid. This relative selectivity of the electrochemical transducers and polymers allowed us to discriminate between HP (at Pt/pPD surface) and DA (at Ep/pDA surface) and record their changes
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
Development of a new electrochemical device for the determination of dopamine auto-oxidation
No full textOxidative stress, caused by reactive oxygen species (ROS), is responsible of the dopaminergic neuronal death at nigrostriatal
level, as it occurs in Parkinson's Disease (PD, Serra et al. 2002). During PD, ROS are responsible of the non
enzymatic oxidation of dopamine (DA, so called auto-oxidation) but, at the same time, this process enhances the
production of ROS with an amplification of dopaminergic pathways damage. Both, the non-enzymatic dopamine autooxidation
and the enzymatic one, mainly mediated by monoamine oxidase enzyme (MAO), determine the formation of the
corresponding ortho-quinone with the production of anion superoxide (O2
-) and hydrogen peroxide (HP). In this study we
have developed a novel electrochemical device able to monitor the auto-oxidation of DA, induced by HP, exploiting the
different catalytic properties of the materials used as electrochemical transducers. The system consists of an
electrochemical cell in which there is a buffer solution at pH 7.4, reproducing the cerebral extracellular environment, an
Ag/AgCl pseudoreference electrode, an auxiliary electrode and two working electrodes, one made with epoxy/carbon
(Ilinoiu et al. 2013) and the other one with platinum/iridium (Pt/Ir, Calia et al., 2015). Both sensors were coated with a polydopamine
(poly-DA) permselective polymer (Zhou P. et al. 2014) able to record the redox interactions between the DA and
the HP in a homogeneous phase and in the presence of interfering molecule such as ascorbic acid (AA) or other
electroactive anions (DOPAC, UA, 5-HIAA, etc.), normally present in the fluids of the central nervous system (Calia et al.
2009). The developed system, optimized during the study, allowed the oxidation of DA and HP at platinum surface while
the only DA was oxidized at carbon surface. This relative selectivity of the electrochemical transducers allowed us to
discriminate between HP and DA and record their changes in the homogeneous phase by constant potential amperometry.
The device, coupled with a dual-channel telemetric transmitter, has been used for studying the time curse of DA autooxidation
in the extracellular compartment of PC12 cells exposed to HP and the protective properties of several
antioxidants.
Serra P. A. et al. (2002). M. S. J. Biol. Chem. 277, 34451–33461
Ilinoiu E. C. et al. (2013). Sensors (Basel). 13(6):7296-307.
Calia et al. (2015). Analyst. 140(10):3607-15
Zhou P. et al. (2014 ). PLoS One. 9(11):e113087
Calia et al. (2009). Sensors (Basel).9(4): 2511–2523
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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