1,720,962 research outputs found
Mechanical Response of Short Fiber Reinforced Fly Ash Based Geopolymer Composites
No full textThe requirement for environmentally friendly construction materials for sustainable development is nowadays an important issue and the geopolymer technology provides a good solution to replace, as binder, the ordinary cement materials for green building. Fly ash, an industrial by-product currently disposed of as waste, can be used as feedstock for geopolymers with an excellent greenness. In order to preserve the eco-friendly nature of the fly ash based geopolymer and enhance the mechanical properties that represent a weak point of the cementitious materials, limiting their application fields, a new fly ash based geopolymer composite was introduced. For this purpose, inorganic, organic and natural short fibers, i.e. Eglass, aramid and hemp respectively, were considered as reinforcement. The mechanical response of these composites under quasi-static and dynamic load conditions was investigated and compared to plain geopolymers, drawing the attention to the hemp reinforced ones, because of their low coast and eco-friendly nature
Pluronic F127- Alginate blends as gel-paving for coronary drug eluting stent
No full textIn this work a technique to realize a pluronic-alginate gel covering of stent by simple and repeatable operations at low cost was presented. To test the gel-paving resistance (with and without drug loading) to erosion phenomena when exposed to a fluid mimicking the blood flux, a dedicated device, named Simulated Artery Device, SAD, was built to simulate the human circulatory apparatu
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
Injectable Chitosan/β-Glycerophosphate System for Sustained Release: Gelation Study, Structural Investigation, and Erosion Tests
No full textHydrogels can constitute reliable delivery systems of drugs, including those based on nucleic
acids (NABDs) such as small interfering ribonucleic acid (siRNA). Their nature, structure, and response
to physiological or external stimuli strongly influence the delivery mechanisms of entrapped active
molecules, and, in turn, their possible uses in pharmacological and biomedical applications. In this
study, a thermo-gelling chitosan/β-glycero-phosphate system has been optimized in order to assess its
use as injectable system able to: i) gelling at physiological pH and temperature, and ii) modulate the release
of included active ingredients. To this aim, we first analyzed the effect of acetic acid concentration
on the gelation temperature. We then found the “optimized composition”, namely, the one in which the
Tgel is equal to the physiological temperature. The resulting gel was tested, by low field nuclear magnetic
resonance (LF-NMR), to evaluate its average mesh-size, which can affect release kinetics of loaded
drug. Finally, films of gelled chitosan, loaded with a model drug, have been tested in vitro to monitor
their characteristic times, i.e. diffusion and erosion time, when they are exposed to a medium mimicking
a physiological environment (buffer solution at pH 7.4). Results display that the optimized system is
deemed to be an ideal candidate as injectable gelling material for a sustained relea
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
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