1,721,084 research outputs found
All-Optical Electrochemiluminescence
No full textElectrochemiluminescence (ECL) is widely employed for
medical diagnosis
and imaging. Despite its remarkable analytical performances, the technique
remains intrinsically limited by the essential need for an external
power supply and electrical wires for electrode connections. Here,
we report an electrically autonomous solution leading to a paradigm
change by designing a fully integrated all-optical wireless monolithic
photoelectrochemical device based on a nanostructured Si photovoltaic
junction modified with catalytic coatings. Under illumination with
light ranging from visible to near-infrared, photogenerated holes
induce the oxidation of the ECL reagents and thus the emission of
visible ECL photons. The blue ECL emission is easily viewed with naked
eyes and recorded with a smartphone. A new light emission scheme is
thus introduced where the ECL emission energy (2.82 eV) is higher
than the excitation energy (1.18 eV) via an intermediate electrochemical
process. In addition, the mapping of the photoelectrochemical activity
by optical microscopy reveals the minority carrier interfacial transfer
mechanism at the nanoscale. This breakthrough provides an all-optical
strategy for generalizing ECL without the need for electrochemical
setups, electrodes, wiring constraints, and specific electrochemical
knowledge. This simplest ECL configuration reported so far opens new
opportunities to develop imaging and wireless bioanalytical systems
such as portable point-of-care sensing devices
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
Preparation and study of metal oxides for photoelectrochemical applications
No full textCette thèse de doctorat porte sur la préparation et l’étude d’oxydes semi‐ conducteurs et de leurs applications dans des cellules photoélectrochimiques. Nous avons étudié en particulier le vanadate de bismuth BiVO₄ pour la photooxydation de l’eau et la photoélectrochimiluminescence et l’oxyde de fer α-Fe₂O₃ -Fe2O3 pour la détection du H₂O₂. Nous proposons une nouvelle méthode de fabrication de BiVO₄ par électrodéposition du bismuth en milieu basique. Nous avons aussi montré que le revêtement de cette surface par une couche amorphe catalytique de FeOx permet d’améliorer considérablement la performance de cette photoanode pour l’oxydation de l’eau. De même, nous avons rapporté une méthode simple pour le dépôt de couches d'hématite sur du FTO et l’utilisation de ces surfaces pour la détection photoélectrochimique du H₂O₂. Ce système est robuste et permet de détecter expérimentalement du H₂O₂ à des concentrations sous‐micromolaires. Finalement, dans ce travail, le BiVO₄ a été utilisé pour la première fois pour l’électrochimiluminescence. Pour cela, nous avons étudié la luminescence d’un dérivé du luminol à des photoanodes BiVO₄ ce qui a permis de mettre en évidence la possibilité de contrôler son intensité.This doctoral thesis focuses on the preparation and study of semiconductor oxides and their applications in photoelectrochemical cells. In particular, we studied bismuth vanadate BiVO₄ for water photooxidation and photoelectrochemiluminescence and iron oxide α-Fe₂O₃ for the detection of H₂O₂. We propose a new method for manufacturing BiVO₄ by electrodeposition of bismuth in a basic medium. We have also shown that coating this surface with a catalytic amorphous layer of FeO x improves the performance of this photoanode for water oxidation. Likewise, we have reported a simple method for the deposition of hematite layers on FTO and the use of these surfaces for the photoelectrochemical detection of H₂O₂. This system is robust and allows to experimentally detect H₂O₂ at sub‐micromolar concentrations. Finally, in this work, BiVO₄ was used for the first time for electrochemiluminescence. To do that, we studied the luminescence of a luminol derivative at BiVO₄ photoanodes, which allows to finely control the intensity of the luminescence
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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