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Dental implant with nanotubes surface with micrometric cavities
No full textIn the dental implant, of titanium or its alloys, at least that surface of the implant intended to come into contact with the gingival epithelium has a structure of the titanium oxide nanotube type, with cavities of micrometric dimensions
Mechanical properties and shock absorption of dental implants equipped with abutments made of composite matherials
No full textThe modern dental endosseous implants include some parts which can be mounted at successive time steps of the tooth replacement. Due to their different requirements - mechanical, aesthetic or related to the comfort -the parts can be profitably constituted by different materials, homogeneous or composite. A crucial component is the abutment connecting the "artificial root" integrated into the bone to the artificial tooth: it is subjected high to axial and transversal loads and preferably it must be clear or semi-transparent because the artificial tooth is not completely opaque. Some composite materials have been tested and compared with the classic components made of titanium alloy. Preliminary in vivo long term analysis on the bone surrounding the implants show that the bone re-absorption rate decreases for the implants equipped with some composite abutments. In order to better understand the implants behavior, the pieces have been tested by means of quasi static and dynamic bending tests and fatigue tests; the damping level of the implant system have been tested by means of vibration and impact tests. The test equipment includes an artificial tooth to be impacted and an implant frame, both instrumented with accelerometers. The results highlight that the impact peaks transmitted from the tooth to the bone vary with the abutment material. These findings together with the information on fatigue strength of the pieces can drive the design of new endossoeus implants. A numerical model of the implant for dynamic simulation, which take into account the distribution and the direction of the fibers of each layer of the composite material, allows to optimize the system mechanical properties. The next step of the research will be the in vivo and mechanical test of the optimized abutments
Guarigione ossea intorno a impianti in titanio plasma – spray e titanio plasma – spray rivestito in TiN
No full text
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
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