1,720,975 research outputs found
Expanding the role of Src and protein-tyrosine phosphatases balance in modulating osteoblast metabolism: Lessons from mice
No full textThe widespread nature of protein phosphorylation/dephosphorylation underscores its key role in cell signaling metabolism, growth and differentiation. Tyrosine phosphorylation of cytoplasmic proteins is a critical event in the regulation of intracellular signaling pathways activated by external stimuli. An adequate balance in protein phosphorylation is a major factor in the regulation of osteoclast and osteoblast activities involved in bone metabolism. However, although phosphorylation is widely recognized as an important regulatory pathway in skeletal development and maintenance, the mechanisms involved are not fully understood. Among the putative protein-tyrosine kinases (ptk) and protein-tyrosine phosphatases (ptp) involved in this phenomenon there is increasing evidence that Src and low molecular weight-ptps play a central role in a range of osteoblast activities, from adhesion to differentiation. A role for Src in bone metabolism was first demonstrated in Src-deficient mice and has since been confirmed using low molecular weight Src inhibitors in animal models of osteoporosis. Several studies have shown that Src is important for cellular proliferation, adhesion and motility. In contrast, few studies have assessed the importance of the ptk/ptp balance in driving osteoblast metabolism. In this review, we summarize our current knowledge of the functional importance of the ptk/ptp balance in osteoblast metabolism, and highlight directions for future research that should improve our understanding of these critical signaling molecules. (C) 2010 Elsevier Masson SAS. All rights reserved
A simple method for enhancing cell adhesion to hydroxyapatite surface
No full textFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Objectives Increase cell adhesion on hydroxyapatite (HA) surface, in a simple, fast and inexpensive way. Material and methods Hydroxyapatite powder was immersed into deionized water for 15 days, dried and pressed into discs. On those discs, pre-osteoblasts cells were cultured for 30 min and 24 h, and adhesion was analyzed by MTT reduction. Results The results show that HA treatment in equilibrium with water drastically increases cell adhesion when compared with cultures on HA with no treatment. The results also show that one essential factor required for a complete modification of HA is the amount of time of immersion in water. Conclusions The work presented here suggests a new, simple and effective method to improve the success of different implants. The method is simple, inexpensive and can be used in the daily routine of different contexts where implants are used, from bone substitution to dental procedures. To cite this article:Bertazzo S, Zambuzzi WF, Campos DDP, Ferreira CV, Bertran CA. A simple method for enhancing cell adhesion to hydroxyapatite surface.Clin. Oral Impl. Res. 21, 2010; 1411-1413.doi: 10.1111/j.1600-0501.2010.01968.x.211214111413Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Bioactivation of alumina by surface modification: a possibility for improving the applicability of alumina in bone and oral repair
No full textFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In regenerative medicine, surface engineering of bioinert synthetic materials is often required in order to introduce bioactive species that can promote cell adhesion, proliferation, viability and enhanced ECM-secretion functions. The aim of this work is to study cell interaction with alumina-modified surfaces. In this work, chemical properties of alumina surface were changed by a reaction at the surface of alumina with low molecular weight dicarboxylic acid, which produced carboxyl groups. These carboxyl groups were able to complex with Ca(2+) on the surface, forming sites of precipitation for calcium phosphates that make alumina biocompatible, as indicated by cell culture of pre-osteoblasts (MC3T3-E1 cell line). The procedure presented in this work shows that the insertion of specific functional groups on the surface of alumina increases cell interaction with the surface of alumina. This knowledge can be important in oral science and orthopedics, for the construction of prosthesis. To cite this article:Bertazzo S, Zambuzzi WF, da Silva HA, Ferreira CV, Bertran CA. Bioactivation of alumina by surface modification: a possibility for improving the applicability of alumina in bone and oral repair.Clin. Oral Impl. Res. 20, 2009; 288-293.doi: 10.1111/j.1600-0501.2008.01642.x.203288293Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
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
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
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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