1,720,965 research outputs found
Microscale approaches for molecular regulation of skeletal development
No full textCells reside in dynamic, three-dimensional (3-D) microenvironments, which regulate their ability to respond to the spatiotemporal cues, such as neighbouring cells, the extracellular matrix, soluble factors and physical forces. Microscale technologies are rapidly emerging as key strategies to recapitulate the 3-D microarchitecture of the tissue, and the complex biochemical milieu and dynamic biomechanical cues of the in vivo cellular microenvironment. An overview of principal microscale approaches that have been successfully applied to promote skeletal development through augmentation of skeletal cell growth and differentiation is presented in this chapter. The microscale approaches include micropatterning techniques to fabricate defined microtopographies for directing skeletal cell differentiation; high-throughput material formulation and microarray techniques, in combination with microfabrication approaches, for rapid screening, selection and fabrication of 3-D biomaterial scaffolds with microscale resolution, which offers increased control of the cellular microenvironment and improved ability to direct skeletal stem cell fate; application of microbioreactors and microfluidic scaffolds for culturing skeletal cells in closely regulated 3-D microenvironments that recapitulate the organ-specific microarchitecture and dynamic physical forces crucial for manipulation of long-term skeletal cell growth and differentiation; and microinjection/micromanipulation techniques for modulation of skeletal development in ex vivo models, followed by analyses of skeletal development and 3-D bone microarchitecture using microcomputed tomography. Thus, microscale technologies have enhanced our ability to generate physiologically relevant ex vivo microscale skeletal tissue models, which effectively recapitulate in vivo tissue development and function, and have the potential to be used for the development of skeletal disease models and for pharmacological and toxicological drug screenin
Prospective isolation of human bone marrow stromal cell subsets: a comparative study between Stro-1-, CD146- and CD105-enriched populations
No full textStro-1 has proved an efficacious marker for enrichment of skeletal stem and progenitor cells although isolated populations remain heterogeneous, exhibiting variable colony-forming efficiency and osteogenic differentiation potential. The emerging findings that skeletal stem cells originate from adventitial reticular cells have brought two further markers to the fore including CD146 and CD105 (both primarily endothelial and perivascular). This study has compared CD146-, CD105- and Stro-1 (individual and in combination)-enriched human bone marrow stromal cell subsets and assessed whether these endothelial/perivascular markers offer further selection over conventional Stro-1. Fluorescent cell sorting quantification showed that CD146 and CD105 both targeted smaller (2.22% ± 0.59% and 6.94% ± 1.34%, respectively) and potentially different human bone marrow stromal cell fractions compared to Stro-1 (16.29% ± 0.78%). CD146+, but not CD105+, cells exhibited similar alkaline phosphatase-positive colony-forming efficiency in vitro and collagen/proteoglycan deposition in vivo to Stro-1+ cells. Molecular analysis of a number of select osteogenic and potential osteo-predictive genes including ALP, CADM1, CLEC3B, DCN, LOXL4, OPN, POSTN and SATB2 showed Stro-1+ and CD146+ populations possessed similar expression profiles. A discrete human bone marrow stromal cell fraction (2.04% ± 0.41%) exhibited positive immuno-labelling for both Stro-1 and CD146. The data presented here show that CD146+ populations are comparable but not superior to Stro-1+ populations. However, this study demonstrates the critical need for new candidate markers with which to isolate homogeneous skeletal stem cell populations or skeletal stem cell populations which exhibit homogeneous in vitro/in vivo characteristics, for implementation within tissue engineering and regenerative medicine strategies
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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