1,720,954 research outputs found
Development of a cartilage tissue engineering construct based on hASCs spheroids differentiated under hypoxia in a chitosan/chitin nanocrystals 3D scaffold.
Full text link212 p.The generation of a cartilage tissue engineering (TE) construct is currently a viable strategy for the treatment of osteoarthritis. Such construct requires a biomaterial with optimal properties, including biocompatibility, biodegradability and porosity, among others. Natural polymers like, CH and CS are attractive building block for the development of biomaterials for TE applications. We investigated the role of the incorporation of chitin nanoforms (i.e., nanocrystals or nanofibers) into Genipin-chitosan crosslinked (GCS) matrices designed in two different shapes, 2D films and 3D porous scaffolds. The aim was to assess the potential of these biomaterials as support for L-929 murine fibroblast cell line and human adipose-derived stem cells (hASCs) growth.The incorporation of chitin nanocrystals or nanofibers on the GCS 2D films and 3D porous scaffolds displayed better swelling properties and enhanced the mechanical performance when compared to nanoform-free GCS materials. Furthermore, our data showed that these biomaterials provide topological cues to support hASCs growth. The incorporation of low concentration of chitin nanoforms, in particular,was found to be the most appropriate supports for the proliferation and adhesion of hASCs.As cell source, hASCs have shown potential for cartilage regeneration when cultured in the appropriate conditions. Moreover, it has been suggested that physiological low oxygen (hypoxia) can significantly improve hASCs adhesion, proliferation and chondrogenic differentiation while preventing their osteogenic differentiation. We first investigated the chondrogenic potential of the hASCs spheroids and demonstrated that were positive to cartilage-specific markers including collagen type II (COL2A1) and aggrecan (ACAN), while lacked expression in the osteogenic differentiation marker collagen type I (COL1A2). Moreover, hypoxia inducible factor 1¿, which positively directs COL2A1 and ACAN expression, was upregulated in chondrospheroids cultured under hypoxia.Finally, this 3D culture hypoxic system created a pro-chondrogenic environment that allowed hASCs to differentiate into the chitosan/chitin nanocrystals 3D porous scaffold producing a chondral extracellular matrix with a high sulphated glucosaminoglycan content, which is characteristic of articular cartilage. This 3D chondrogenic differentiation model mimics the in vivo cartilage environment during the embryonic development, which entails a further step in cartilage TE, having potential application for articular cartilage regeneration
Development of a cartilage tissue engineering construct based on hASCs spheroids differentiated under hypoxia in a chitosan/chitin nanocrystals 3D scaffold.
Full text link212 p.The generation of a cartilage tissue engineering (TE) construct is currently a viable strategy for the treatment of osteoarthritis. Such construct requires a biomaterial with optimal properties, including biocompatibility, biodegradability and porosity, among others. Natural polymers like, CH and CS are attractive building block for the development of biomaterials for TE applications. We investigated the role of the incorporation of chitin nanoforms (i.e., nanocrystals or nanofibers) into Genipin-chitosan crosslinked (GCS) matrices designed in two different shapes, 2D films and 3D porous scaffolds. The aim was to assess the potential of these biomaterials as support for L-929 murine fibroblast cell line and human adipose-derived stem cells (hASCs) growth.The incorporation of chitin nanocrystals or nanofibers on the GCS 2D films and 3D porous scaffolds displayed better swelling properties and enhanced the mechanical performance when compared to nanoform-free GCS materials. Furthermore, our data showed that these biomaterials provide topological cues to support hASCs growth. The incorporation of low concentration of chitin nanoforms, in particular,was found to be the most appropriate supports for the proliferation and adhesion of hASCs.As cell source, hASCs have shown potential for cartilage regeneration when cultured in the appropriate conditions. Moreover, it has been suggested that physiological low oxygen (hypoxia) can significantly improve hASCs adhesion, proliferation and chondrogenic differentiation while preventing their osteogenic differentiation. We first investigated the chondrogenic potential of the hASCs spheroids and demonstrated that were positive to cartilage-specific markers including collagen type II (COL2A1) and aggrecan (ACAN), while lacked expression in the osteogenic differentiation marker collagen type I (COL1A2). Moreover, hypoxia inducible factor 1¿, which positively directs COL2A1 and ACAN expression, was upregulated in chondrospheroids cultured under hypoxia.Finally, this 3D culture hypoxic system created a pro-chondrogenic environment that allowed hASCs to differentiate into the chitosan/chitin nanocrystals 3D porous scaffold producing a chondral extracellular matrix with a high sulphated glucosaminoglycan content, which is characteristic of articular cartilage. This 3D chondrogenic differentiation model mimics the in vivo cartilage environment during the embryonic development, which entails a further step in cartilage TE, having potential application for articular cartilage regeneration
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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