1,721,030 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
Vascular endothelial growth factor. From basic research to clinical application
No full textThere is increasing evidence to support the concept that growth and metastasis of solid tumors, including those of gastrointestinal tract, is facilitated by neoangiogenesis. Vascular Endothelial Growth Factor (VEGF) is one of the most powerful known inducer of endothelial cell growth. Therefore, VEGF is likely to contribute to tumor growth by promoting angiogenesis and stroma formation both directly, through its neovascularization inducing activity, and indirectly, by increasing vascular permeability. In addition, VEGF facilitates tumor diffusion favouring metastatic spread of cancer cells. In view of these implications, it is important to understand the physiopathological role played by this factor. In this review the authors present the accumulating body of data on the biological and functional properties of VEGF, paying special reference to new evidence on its contribution in tumor immune escape, through a marked inhibition of differentiation and activity of the professional antigen presenting cells (APC), namely dendritic cells (DC). As the molecular and cellular events that underlie the functional role of VEGF in tumor angiogenesis and immune suppression become better defined, rational pharmacological and/or gene therapies can be derived in order to treat those neoplasms, such as pancreatic adenocarcinoma, not well amenable to chemo- and radiotherapy or immunotherapy
High serum levels of Transforming Growth Factor-beta1, Interleukin-10 and Vascular Endothelial Growth Factor in pancreatic adenocarcinoma patients
No full textBACKGROUND:
Pancreatic adenocarcinomas are among the most aggressive types of cancer with an extremely poor diagnosis. Since this type of cancer is not well amenable to chemo- and radiotherapy or immunotherapy, surgical resection remains the only feasible treatment to date. Transforming Growth Factor (TGF)-beta and Interleukin (IL)-10 are potent immunomodulators that have been shown to suppress several aspects of the immune response. Vascular Endothelial Growth Factor (VEGF) is a powerful angiogenic factor, recently thought to be involved in neoangiogenesis and metastasis spreading. Therefore the three cytokines may contribute, by different pathways, to immune escape and growth of tumor. This study was conducted to determine the possible significance of TGF-beta1, IL-10 and VEGF as markers for monitoring the clinical course of pancreatic adenocarcinoma patients.
METHODS:
Cytokine serum levels were measured in 30 pancreatic cancer patients and in 30 age and sex-matched healthy subjects.
RESULTS:
In comparison to serum concentrations in controls, TGF-beta1, IL-10 and VEGF levels were significantly elevated in all patients. Where the patients were divided by groups on the basis of the clinical stage of the disease, no differences were observed in TGF-beta1 levels among the groups. On the contrary, IL-10 and VEGF were more represented in stage IV patients than in stage II and III patients. In addition, the 14 patients who underwent surgical resection had postoperative cytokine serum levels markedly lower than those observed at diagnosis.
CONCLUSIONS:
Overall, the results suggest the importance of these markers in predicting the biological activity of the disease and suggest new targets for future rational therapies
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
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