1,720,970 research outputs found
miRNA 34a, 100, and 137 modulate differentiation of mouse embryonic stem cells
No full textMicroRNAs (miRNAs) play an important
role in proper function and differentiation of mouse
embryonic stem cells (ESCs). We performed a systematic
comparison of miRNA expression in undifferentiated
vs. differentiating ESCs. We report that 138 miRNAs
are increased on the induction of differentiation. We
compared the entire list of candidate mRNA targets
of up-regulated miRNAs with that of mRNA downregulated
in ESCs on induction of differentiation.
Among the candidate targets emerging from this analysis,
we found three genes, Smarca5, Jarid1b, and Sirt1,
previously demonstrated to be involved in sustaining
the undifferentiated phenotype in ESCs. On this basis,
we first demonstrated that Smarca5 is a direct target of
miR-100, Jarid1b of miR-137, and we also confirmed
previously published data demonstrating that Sirt1 is a
direct target of miR-34a in a different context. The
suppression of these three miRNAs by anti-miRs caused
the block of ESC differentiation induced by LIF withdrawal.
On the other hand, the overexpression of the
three miRNAs resulted in an altered expression of
differentiation markers. These results demonstrate that
miR-34a, miR-100, and miR-137 are required for
proper differentiation of mouse ESCs, and that they
function in part by targeting Sirt1, Smarca5, and
Jarid1b mRNAs.—Tarantino, C., Paolella, G., Cozzuto,
L., Minopoli, G., Pastore, L., Parisi, S., Russo, T.
miRNA 34a, 100, and 137 modulate differentiation of
mouse embryonic stem cells
Identification of a Novel Transcription Factor Required for Osteogenic Differentiation of Mesenchymal Stem Cells
No full textOsteogenic differentiation is a complex and still poorly understood biological process regulated by intrinsic cellular signals and extrinsic microenvironmental cues. Following appropriate stimuli, mesenchymal stem cells (MSCs) differentiate into osteoblasts through a tightly regulated multistep process driven by several transcription factors and characterized by the expression of a number of bone-specific proteins. In this study, we describe a novel transcription factor that we named osteoblast inducer (ObI)-1, involved in MSC differentiation toward the osteogenic lineage. ObI-1 encodes for a nuclear protein subjected to proteasomal degradation and expressed during osteoblast differentiation both in a murine multipotent mesenchymal cell line (W20-17) and in primary murine MSCs. RNA interference-mediated knockdown of ObI-1 expression significantly impairs osteoblast differentiation and matrix mineralization with reduced expression of the osteogenic markers, Runt-related transcription factor 2 (Runx2) and osteopontin. Conversely, ObI-1 overexpression enhances osteogenic differentiation and bone-specific markers expression. ObI-1 stimulates bone morphogenetic protein (BMP)-4 expression and the consequent activation of the Smad pathway; treatment with a BMP receptor type I antagonist completely abolishes ObI-1-mediated stimulation of osteogenic differentiation. Collectively, our findings suggest that ObI-1 modulates osteogenic differentiation, at least in part, through the BMP signaling pathway, increasing Runx2 activation and leading to osteoblast commitment and maturation
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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