1,720,960 research outputs found
Surface Engineering of Magnesium Alloys for the Next Generation of Biodegradable Device
No full textAlthough the biocompatibility and good mechanical properties make the magnesium and its alloys excellent candidates for biomedical applications, the high corrosion rate, involving hydrogen release and the alkalization of the physiological environment, limit their clinical use. However, this constrain could be exploited for the realization of biodegradable devices. In this regard, it is necessary to ensure a degradation rate comparable to the rate of growth of the hosting tissues, avoiding side effects, premature failures, and adverse reactions. The surface engineering approaches which involve the use of a coating made of single or multiple layers represent a possible method to tailor the deterioration rate. The poor adhesion strength between layers could be an important drawback of this approach. In the present research, a multilayer coating composed of an oxide layer, a bio-inspired polydopamine (PDA)-based one and a biodegradable polymer film, made of polylactic acid (PLA) has been realized on magnesium alloys substrates. The first layer was obtained by a plasma electrolytic oxidation (PEO) treatment to increase the corrosion resistance. Then, the polydopamine layer has been applied by the dip-coating method to improve the adhesion between the oxide layer and the polylactic acid film. Each layer and their combinations were characterized by using morphological examinations, and electrochemical test by means of potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS) methods. The use of a multilayer coating has demonstrated to be a promising strategy to control the degradation rate of the magnesium alloys to produce biodegradable device
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
Designing the Surface of Medical Devices
No full textThe most important properties of metal medical devices are i) biocompatibility, ii) mechanical strength and, in some cases, iii) reliable osseointegration. The surface of biodevices can be designed and then modified to improve these properties. After a brief review of the technologies used to modify the surface of metallic biodevices, some examples of surface treatments used to improve their properties are given. The effect of acid etching on the surface shape of the metal material to improve implant osseointegration, to produce a surface with more ‘valleys’ than ‘peaks’, a requirement for improved osseointegration, is shown. It is demonstrated that the “shape” of the surface can be easily and quantitatively measured by using appropriate roughness parameters. In addition, to reduce the risk of implant rejection, nanoscale reservoirs for controlled drug delivery can be formed on the previously acid-etched implant surface. To this end, the methods used to grow titania nanotube dental screws from commercially pure titania are presented. The shape and length of the nanotubes can be varied to increase or decrease the duration of drug delivery as required
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
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
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