1,721,027 research outputs found
Immediate cell signal induced by laminin in rat Sertoli cells
No full textRat Sertoli cells in primary culture have been studied for their ability to respond to extracellular matrix macromolecules by increases of [Ca2+](i). We observed that cells seeded oil glass coverslips, loaded with the intracellular Ca2+ indicator fura-2, responded to laminin, but nut to fibronectin, with an immediate [Ca2+](i) raise, with a peak followed by a prolonged plateau. [Ca2+](i) increases were dependent upon Ca2+ influx across the plasma membrane and Ca2+ release from intracellular Ca2+ pools. Ca2+ influx was inhibited by extracellular Ca2+ removal by EGTA, and by treatment with La3+, or with the L-type voltage operated Ca2+ channel blocker, nifedipine. Ca2+ release from intracellular Ca2+ storing organelles, was inhibited by the microsomal Ca2+-ATPase blocker thapsigargin. Responses were mimicked by synthetic peptides carrying the Arg-Gly-Asp adhesion sequence, but not by the control Arg-Gly-Glu-containing peptide, in which aspartic acid was replaced by glutamic acid. Laminin-dependent [Ca2+](i) increases were down-regulated by the follicle-stimulating hormone. However, this occurred only when cells were not subjected to homotypic cell-cell contact, and responded to the hormone with a significant [Ca2+](i) elevation. These results indicate that laminin may regulate Sertoli cells by intracellular signals that perturb Ca2+ homeostasis. This role may be related to an effect exerted by the seminiferous epithelium basement membrane on the regulation of spermatogenesis. (C) 2000 Elsevier Science B.V./International Society of Matrix Biology. All rights reserved
Microgravity accelerates differentiation, induces apoptosis and stimulates interleukin 6 expression in osteoblast-like cells
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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
Long-term outcome of nephropathic cystinosis: a 20-year single-center experience.
No full textNephropathic cystinosis (NC) is a severe disease that is complicated by early-onset chronic renal failure (CRF) and other complications related to cystine deposition in tissue. Since the 1980s, the prognosis of NC has dramatically improved after the introduction of cysteamine treatment. Limited data are available documenting improvement in prognosis. We reviewed our long-term data (follow-up 6.3-27.8 years) on 23 patients followed in the past 26 years. Overall, stage III CRF was reached at 10 years of age in >90\% of patients, whereas >80\% reached end-stage renal disease before the age of 14 years. Three patients died during the follow-up. Our analysis shows a clear improvement in renal outcome (p = 0.001) and linear growth (p = 0.04) in patients treated more recently. Improvement in the evolution of renal function was significantly associated with early initiation of cysteamine (p = 0.006), with the dose of cysteamine (p = 0.04), and with the use of angiotensin-converting enzyme inhibitors (p = 0.01). Nonrenal long-term complications are similar to previously reported data. Of note, 3/23 patients developed rare forms of primary tumors that were successfully treated. In conclusion, our experience shows a significant improvement in the renal and nonrenal complications of cystinosis over the past decades and highlights the importance of early diagnosis in order to initiate cysteamine as soon as possible
Coupling NANF to Silicon Photonics circuits
No full textWe present the first demonstration of optical coupling between hollow core fibers and Silicon Photonics circuits. We achieved moderate excess coupling loss with respect to SMF-28 and achieved 25 Gb/s data transmission over NANF fibers.</p
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