1,721,039 research outputs found
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
Hot Air Coating microparticles: I. Drug release mechanism
No full textThe aim of this work was to evaluate the kinetics and the mechanism of the drug release process from microparticles prepared by Hot Air Coating (HAC) technique. An antiarrhythmic drug (PRF06) was the active molecule and cetearyl alcohol and Pluronic F68 were the excipients. Setting the optimal operating conditions, microparticles were obtained; they were collected, separated by sieving into five size fractions and characterized. Drug release test was carried out on each single fraction of microparticles and the Weibull Function and the exponential kinetic model were applied to the experimental data.
The results show that the size of the microparticles affects the drug release profile. Moreover the absence of a burst-effect indicates that the drug crystals are not on the particles surface, but are coated by the mixture of the excipients. The application of the Weibull model gives values of the Weibull parameter b close to 1, indicating that the shape of the dissolution curves is exponential. All the results suggest that a diffusive mechanism governs the drug release from HAC microparticles
Study of the effects of Pluronic F68 on nifedipine microparticles prepared by Hot Air Coating technique
No full textIn the present work microparticles prepared by Hot air Coating (HAC) technique and costing of nifedipine (nife), cetearyl alcohol (CA) and Pluronic F68 (F68) were investigated as a potential therapeutic system. The characteristics of these microparticles were evaluated by thermogravimetric analysis electron microscopy and dissolution study. The results obtained by TGA, SEM and dissolution study show that Hot Air Coating technique significantly modifies the morphology of the nife-CA/F68 system and the dissolution of nifedipine. Moreover, it can be drawn that Pluronic F68 allows to modulate the release of nifedipine coated with cetearyl alcohol by this new spray process
Effect of spray baking conditions on the chemical and physical properties of nifedipine
No full textSpray techniques are appealing in the pharmaceutical field, because of their versatility: they allow to prepare microparticulate sustained drug delivery systems, starting from solid or liquid materials, such as suspensions, emulsions and solutions. More recently a valid alternative method to spray congealing, the Spray baking process (SB), has been proposed for the encapsulation of pharmaceutical substances. By this new technology, in certain operative conditions, a mixture of solid substances is heated and immediately cooled to form microcapsules.
In this work we have evaluated the efficiency of Spray Baking method as a tool to produce a microcapsulate system for nifedipine and to examine its influence on chemical physical integrity of the drug, on size and morphology of the microcapsules obtained.
SB treatment allows to obtain an entrapment efficiency of 98% nifedipine in microcapsules. Chromatographic analysis doesn't reveal the presence of peaks associable to degradation products of the drug.
These results indicate that Spray Baking technique allows to obtain nifedipine microcapsules with a high entrapment efficiency: it is therefore a valid method of microencapsulation, alternative from conventional methods. During treatment, nifedipine maintains its crystalline habitus and the fast heating in the apparatus does not modify its chemical structure. Pre-treatment process significantly affected microcapsules properties
Injectable multicomposite calcium phosphate bone cement as a drug delivery system for the treatment of bone infection
No full textDispelling 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
- …
