1,720,985 research outputs found
Interazione tra B1-INTEGRINA e SEL1L nello sviluppo del pancreas
No full textBeta1-Integrin and SEL1L interaction in pancreas development Diaferia Giuseppe In the present study we looked at the role of beta1-integrin and SEL1L in beta-cell differentiation through ECM interaction. Using beta-cell specific beta1-integrin KO we showed a dramatic defect in cell-adhesion on extracellular matrixes and a marked reduction in beta-cell mass due to a defect in beta-cell proliferation confirmed by the loss of cyclin D1 expression and the upregulation of the inhibitors p21 and p27. In contrast glucose tolerance was enhanced due to the increased insulin sensitivity. Using an in vitro model of human pancreas development we found SEL1L highly expressed in the developing islet cell clusters and at the basal membrane of undifferentiated acini of the fetal pancreatic tissue while restricted to islet cells in the adult pancreas. In vitro expansion of fetal and adult islet cell clusters on extracellular matrixes as netrin-1 led to a significative upregulation of insulin and PDX-1 expression as well as SEL1L. Coimmunoprecipitation experiments of SEL1L with beta1-integrin suggest that this effect, mediated by ECM, are likely to be integrin dependent. These results point to the essential role of beta1 integrin and SEL1L signaling in pancreatic cell development and proliferatio
Is stem cell chromosomal stability affected by cryopreservation conditions?
No full textThe use of in vitro cultured stem cells in cell therapy, must meet at least two requirements: the preservation of a normal genetic karyotype and maintenance of integrity during long term-culturing and storage in liquid nitrogen tanks. Here we report on the karyological characterization of neural stem cells derived from adult (ANS) subentricular zone (SVZ), mouse fetal cotex cells, mESCs cells NS46 (LC-1) and related engineered clones as well as Neurospheres from the mouse striatum Li-4. The results show a series of chromosomal aberrations present in these cells in agreement with previous reports. On the other hand, karyotyping of the human neural stem cell lines derived from hESCs (H9-hNCPC) and fetal cerebellum (CB541) showed a stable genomic asset with few chromosomal aberration. These results underscore the importance of performing routine cytogenetic analysis before using the cells to produce chimeric mice or in studies of lineage specific differentiation. We are also evaluating the use of Cell microarray for high-throughput screening of stem cell differentiation by immunocytochemical analysis. With this technique we were able to follow the expression of neural differentiation markers and the involvement of SEL1L gene in stem cell self-renewal
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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