1,721,095 research outputs found
Biological response of human bone marrow mesenchymal stem cells to fluoride-modified titanium surfaces
No full textObjectives The aim of the present study was to examine the behaviour of human bone marrow-derived mesenchymal stem cells (BM-MSC) to fluoride-modified grit-blasted (F-TiO) titanium surfaces compared with grit-blasted ones (TiO). Material and methods Implant surfaces were analysed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). BM-MSC were isolated from healthy donors and grown on the implant surfaces. Cell adhesion and proliferation, type I collagen (Col I) synthesis, osteoblastic differentiation (in terms of alkaline phosphatase activity, osteocalcin synthesis and extracellular matrix mineralization) were assessed. Furthermore, the ability to affect the osteoblastic/osteoclastic balance in terms of osteoprotegerin (OPG) and activator of nuclear factor kappa B ligand (RANKL) ratio was investigated. Results F-TiO surface showed higher S(a) values (P < 0.05) and the presence of nano-scale structures at the AFM and SEM analysis. Comparable cell morphology and similar adhesion values on both surfaces were detected at early time, whereas higher proliferation values on F-TiO samples were observed at 7 and 10 days. Increased Col I and OPG levels for cells grown on F-TiO were found, whereas RANKL was not detectable in any of the conditioned media. BM-MSC showed a similar expression of early and late osteogenic markers on both TiO and F-TiO surfaces. Conclusions The results of the present study show that the chemical and micro/nano-scale modifications induced by fluoride treatment of TiO-grit blasted surfaces stimulate the proliferation and the extracellular matrix synthesis by BM-MSC, as well as the increase of OPG synthesis, thus preventing osteoclast activation and differentiation. To cite this article:Guida L, Annunziata M, Rocci A, Contaldo M, Rullo R, Oliva A. Biological response of human bone marrow mesenchymal stem cells to fluoride-modified titanium surfaces.Clin. Oral Impl. Res. 21, 2010; 1234-1241.doi: 10.1111/j.1600-0501.2010.01929.x
Good reasons for good manners: an argumentative foundation of courtesy in Giovanni Della Casa's Galateo
No full textAny rule or precept listed in the Galateo is justified by its goal, in the context of human interaction. We compare Della Casa's vantage point with recent linguistic models of politeness
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
Efficacia Di Connessioni Meccaniche Tegolo-trave Sull'azione Diaframma Di Strutture Prefabbricate
No full texthe diaphragm effect allows the collaboration of different parts of the lateral load resisting system of a building. If a concrete screed is not poured, as typical for industrial precast structures, such an effect relies on the floor mechanical connec-tions. Starting from the results of local tests on three typical floor-to-beam connections carried out within the framework of the re-search projects Safecast and ReLUIS, simplified macro-models to represent their mechanical behaviour are proposed. A numerical model of a precast structure with mechanical floor-to-beam connections is validated through the comparison against the results of cyclic and pseudo-dynamic tests carried out on a full scale prototype within the framework of the Precast Structures EC8 project. The efficiency of the different technological solution to connect floor and beams on the diaphragm action and on the seismic behav-iour of the structure is then investigated through dynamic non-linear analyses on the bare frame structure and on an externally braced one. A simplified analytical interpretation of the phenomenon is also proposed and validated against the numerical results
BONE MARROW STROMAL CELLS RESPONSE TO FLUORIDE-MODIFIED IMPLANT SURFACES
No full textBackground: The possibility to enhance the biological performance of dental implants by modulating their topographycal and chemical surface features represents a growing aspect of dental research. Fluoride ion incorporation into titanium surfaces has been suggested to positively affect bone cell and tissue response. Being the precursors of the entire osteoblastic lineage, bone marrow stromal cells play a central role in osteogenesis and bone reparative mechanisms, representing an ideal tool to investigate the interaction between bone cells and implant surface
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
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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