1,721,060 research outputs found
Bioactive Glasses Containing Au Nanoparticles. Effect of Calcination Temperature on Structure, Morphology, and Surface PropertiesDOI:10.1021/la100472p
No full textBioactive glasses containing gold nanoparticles (AuNPs) have been synthesized via the sol-gel route usingHAuCl4 x 3H2O as gold precursor. The formation process of AuNPs was studied as a function of the thermal treatment,which induces nucleation of Au particles and influences their nature, optical properties, shape, size, and distribution.The physicochemical characterization indicates that the sample treated at 600 °C presents the best characteristics to beused as a bioactive material, namely high surface area, high amount of AuNPs located at the glass surface, presence ofmicropores, and abundant surface OH groups. In the case of samples either aged at 60 °C or calcined at 150 °C, AuNPsjust begin their formation, and at this stage the gel is not completely polymerized and dried yet. A thermal treatment athigher temperatures (900 °C) causes the aggregation of AuNPs, forming “AuMPs” (i.e., Au microparticles) in adensified glass-ceramic material with low surface area, absence of pores, and low number of surface OH groups. Thesefeatures induce in the glass-ceramic materials treated at high-temperatures a lower bioactivity (evidenced by SBFreaction), as compared with that exhibited by the glass samples treated at 600 °C
Nanostructured gold/conjugated polymer hybrids: Preparation, chemical structure and morphology
No full textConjugated micro and nanostructured Pd containing polymers, derived from a monosubstituted acetylene, namely 3-dimethylamino-l-propyne (DMPA), has been synthesized and used as matrix for the preparation of hybrid systems containing Au(0) nanoparticles, obtained by means of Metal Vapor Synthesis (MVS) technique. By this way the formation of a new heterobimetallic Au/Pd polymeric material was achieved. The novel hybrid was characterized by means of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and high resolution transmission microscopy (HRTEM) showing the Au/polymer interaction and the particle dispersion in the nanostructured polymer matrix. The morphology of the pristine polymer shows dendritic structures or compact enamels and upon formation of the hybrid a high surface extension was observed. HRTEM measurements showed in the Au/Pd-PDMPA hybrid system an almost homogeneously distributed population of gold particles with a main size value of 3.4 +/- 1.4 nm. (c) 2006 Elsevier B.V. All rights reserved
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
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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