1,721,126 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Modelling TGFβR and Hh pathway regulation of prognostic matrisome molecules in ovarian cancer
Get PDFSummary: In a multi-level “deconstruction” of omental metastases, we previously identified a prognostic matrisome gene expression signature in high-grade serous ovarian cancer (HGSOC) and twelve other malignancies. Here, our aim was to understand how six of these extracellular matrix (ECM) molecules, COL11A1, cartilage oligomeric matrix protein, FN1, versican, cathepsin B, and COL1A1, are upregulated in cancer. Using biopsies, we identified significant associations between TGFβR activity, Hedgehog (Hh) signaling, and these ECM molecules and studied the associations in mono-, co-, and tri-culture. Activated omental fibroblasts (OFs) produced more matrix than malignant cells, directed by TGFβR and Hh signaling cross talk. We “reconstructed” omental metastases in tri-cultures of HGSOC cells, OFs, and adipocytes. This combination was sufficient to generate all six ECM proteins and the matrisome expression signature. TGFβR and Hh inhibitor combinations attenuated fibroblast activation and gel and ECM remodeling in these models. The tri-culture model reproduces key features of omental metastases and allows study of diseased-associated ECM
Enhanced invasiveness of breast cancer cell lines upon co-cultivation with macrophages is due to TNF-alpha dependent up-regulation of matrix metalloproteases
No full textApart from the neoplastic cells, malignant tumours consist of the extracellular matrix (ECM) and normal cells, in particular tumour-associated macrophages (TAM). To understand the mechanisms by which TAM can influence tumour cell invasion we co-cultured the human breast cancer cell lines MCF-7, SK-BR-3 and the benign mammary epithelial cell line hTERT-HME1 with macrophages. Co-incubation enhanced invasiveness of the tumour cells, while hTERT-HME1 remained non-invasive. Addition of the broad-spectrum matrix metalloprotease (MMP)-inhibitor FN 439, neutralizing MMP-9 or tumour necrosis factor-alpha (TNF-alpha) antibodies reduced invasiveness to basal levels. As shown by zymography, all cell lines produced low amounts of MMP-2, -3, -7 and -9 under control conditions. Basal MMP production by macrophages was significantly higher. Upon co-incubation, supernatant levels of MMPs -2, -3, -7 and -9 increased significantly, paralleled by an increase of MMP-2 activation. MMP-2 and -9 induction could be blocked by TNF-alpha antibodies. Co-culture of macrophages and hTERT-HME1 did not lead to MMP induction. In the co-cultures, mRNAs for MMPs and TNF-alpha were significantly up-regulated in macrophages, while the mRNA concentrations in the tumour cells remained unchanged. In summary, we have found that co-cultivation of tumour cells with macrophages leads to enhanced invasiveness of the malignant cells due to TNF-alpha dependent MMP induction in the macrophages
Variations on the Author
Get PDF“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
Get PDFWe 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
Human T-lymphotropic virus type 1-induced CC chemokine ligand 22 maintains a high frequency of functional FoxP3+ regulatory T cells
No full textDispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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