1,721,018 research outputs found
Osteopenic bone cell response to strontium-substituted hydroxyapatite.
No full textIonic substitution is a powerful tool to improve
the biological performance of calcium phosphate based
materials. In this work, we investigated the response of primary
cultures of rat osteoblasts derived from osteopenic (OOB)
bone to strontium substituted hydroxyapatite (SrHA),
and to hydroxyapatite (HA) as reference material, compared
to normal (N-OB) bone cells. Strontium (Sr) and calcium
(Ca) cumulative releases in physiological solution are in
agreement with the greater solubility of SrHA than HA,
whereas the differences between the two materials are levelled
off in DMEM, which significantly reduced ion release.
O-OB cells grown on SrHA exhibited higher proliferation
and increased values of the differentiation parameters. In
particular, Sr substitution increased the levels of proliferation,
alkaline phosphatase, and collagen type I, and downregulated
the production of interleukin-6 of O-OB cells,
demonstrating a promising future of SrHA in the treatment of
bone lesions and defects in the presence of osteoporotic bone
Structural and morphological modifications of hydroxyapatite-polyaspartate composite crystals induced by heat treatment.
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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
POLY(L-LACTIC ACID) BASED COMPOSITES WITH A-TRICALCIUM PHOSPHATE AND A POLY(L-LACTIC ACID)-POLY(OXYETHYLENE) DIBLOCK COPOLYMER
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