1,720,969 research outputs found
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
Thyrospheres enriched in stem-like cells from B-CPAP thyroid cancer cell line: morphomolecular characterization
Full text linkMany studies performed over the past years have shown that tumor growth is sustained by a subpopulation of cells with stem-like features (cancer stem cells, CSCs), such as self renewal, multipotency, high migration capacity, drug resistance and aberrant differentiation, but little is known about thyroid tumor CSCs. Among solid tumors, papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer representing up to 80% of thyroid tumors. Isolation and propagation of stem-like cancer cells from established cancer cell lines by sphere forming assay in selective serum-free medium has been extensively reported. We report here the enrichment and morphomolecular characterization of sphere-propagating cells with stem-like properties from the B-CPAP papillary thyroid cancer-derived cell line. Thyrospheres from B-CPAP cells could be propagated up to ten generations. The “stemness” profile was evaluated by functional assays, RT-PCR, western blot, immunocytochemistry. Sphere forming efficiency (SFE) and self renewal increased exponentially at every generation with maximum value at the 8th. Results showed an increase in mRNA expression of stem cell (Oct 3/4, Nanog, ABCG2, Nestin), endodermal (GATA4), tumoral (TP63), and early thyroid differentiated (PAX8, TTF1) markers. A decrease in mRNA expression was observed in late thyroid differentiated marker (TG) along the generation of spheres. Positive staining of Oct3/4, GATA4, Tp63 and TTF1 was also confirmed by immunoblotting and immunocytochemistry. We conclude that thyroid cancer stem/progenitor cell populations are present in the B-CPAP cell line, and that it can represent a model to propagate putative thyroid cancer stem-like cells. Supported by a RAS Grant (Regione Autonoma della Sardegna, P.O.S. FSE 2007-2013, L.R. 7/2007)
Thyrospheres with stem like properties derived from the papillary carcinoma B-CPAP cell line
No full textGenetic alterations distinguishing molecular subtypes of papillary thyroid tumors may influence the behaviour of corresponding stem-like cancer cells
No full textAppropriate 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
Formation of thyrosphere with cancer stem properties from the B-CPAP human papillary thyroid carcinoma cell line
No full textS100B counteracts effects of the neurotoxicant trimethyltin on astrocytes and microglia
No full textCentral nervous system degenerative diseases are often characterized by an early, strong reaction of astrocytes and microglia. Both these cell types can play a double role, protecting neurons against degeneration through the synthesis and secretion of trophic factors or inducing degeneration through the secretion of toxic molecules. Therefore, we studied the effects of S100B and trimethyltin (TMT) on human astrocytes and microglia with two glial models, primary cultures of human fetal astrocytes and a microglia cell line. After treatment with 10(-5) M TMT, astrocytes showed morphological alterations associated with an increase in glial fibrillary acidic protein (GFAP) expression and changes in GFAP filament organization. Administration of S100B before TMT treatment prevented TMT-induced changes in morphology and GFAP expression. A decrease in inducible nitric oxide synthase expression was observed in astrocytes treated with TMT, whereas the same treatment induced NOS expression in microglia. In both cases, S100B prevented TMT-induced changes. Tumor necrosis factor-alpha mRNA expression in astrocytes was not modified by TMT treatment, whereas it was increased in microglia cells. S100B pretreatment blocked the TMT-induced increase in TNF-alpha expression in microglia. To trace the mechanisms involved in S100B activity, the effect of BAY 117082, an inhibitor of nuclear factor-kappa B (NF-kappa B) activation, and of PD98059, an inhibitor of MEK-ERK1/2, were investigated. Results showed that the protective effects of S100B against TMT toxicity in astrocytes depend on NF-kappa B, but not on ERK1/2 activation. These results might help in understanding the role played by glial cells in brain injury after exposure to chemical neurotoxicants and support the view that S100B may protect brain cells in case of injur
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
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