1,721,033 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
Study of crosstalk between G-protein coupled receptor-mediated signals and the Nuclear Factor-κB signal transduction cascade
Get PDFNuclear Factor-κB (NF-κB) is an ubiquitously expressed transcription factor that is activated in response to a broad spectrum of inflammatory stimuli, including the proinflammatory cytokine Tumour Necrosis Factor-α (TNF-α). Whereas NF-κB is pivotal for coordination of the immune/inflammatory response, its excessive activation is associated with the onset and propagation of multiple disease processes. NF-κB activity is mostly studied in cells subjected to proinflammatory stimuli, but in "real life" cells are simultaneously exposed to a plethora of signalling molecules that can modulate NF-κB activity. It has been known for many decades that sympathetic stress modulates immunity and inflammation, yet the molecular bases are not completely understood. Therefore, in this thesis, we focused on the activity of the β2- adrenergic receptor (β2-AR), one of the key mediators of the stress response, as a modulator of NF-κB function.
In line with other reports describing the anti-inflammatory action of β2-AR agonists (β-agonists), we observed that cotreatment of human astrocytes with TNF-α and a β- agonist, inhibited the expression of several NF-κB-driven genes. However, we found that at the same time it potently enhanced the expression of other prototypical NF-κB target genes, including the proinflammatory cytokine Interleukin-6 (IL-6). We found that the IL-6 synergy, depended on the formation of an enhanceosome structure, and hypothesized that the IL-6 promoter acted as a "coincidence" detector, which requires input from multiple signalling cascades for maximal activation. Our previous research was limited to the study of β2-AR/NF-κB crosstalk in the central nervous system, using astrocytes as a cellular model system. In this thesis, we have extended our previous research to skeletal muscle cells. In addition, we have attempted to further unravel the molecular details of the very strong transcriptional synergy apparent at the IL-6 gene using a proteomics approach.
Firstly, we have investigated signalling in response to TNF-α/β-agonist cotreatment in C2C12 cells, a murine skeletal muscle model, representing a physiologically relevant cell type to study β2-AR/NF-κB crosstalk. We observed many similarities in the outcome of β2-AR/NF-κB crosstalk in skeletal muscle cells as compared to astrocytes, although cell-type specific differences in the signalling cascades induced by β- agonists/TNF-α were also apparent. In particular, the very potent synergy at the IL-6 promoter was also detected in skeletal muscle cells. In addition, we found that the expression of several chemokines, influencing the migration potential of undifferentiated skeletal muscle cells, was upregulated upon TNF-α/β-agonist costimulation At the molecular level, we demonstrated that β-agonist-induced potentiation of NF-κB-dependent transcription of the IL-6 gene was associated with histone modifications, chromatin relaxation and formation of an enhanceosome structure.
Secondly, using an unbiased proteomics approach, combining DNA-affinity purification and mass spectrometric analysis, we identified Transcription Enhancer Factor 1 (TEF-1) as a novel interactor of the IL-6 promoter. We found that TEF-1 recruitment to the IL-6 promoter was induced upon TNF-α/β-agonist costimulation and that it acted as a transcriptional repressor. Our results furthermore indicate that TEF-1 modulates the transcriptional activity of CREB, but not NF-κB, and that this is associated with altered accessibility of the IL-6 promoter to transcriptional regulators. Importantly, TEF-1 modulated NF-κB-dependent transcription in a gene selective manner. As the effects of β-agonists appear to be highly gene-selective, further elucidation of its molecular basis might lead to the identification of novel targets for the development of selective NF-κB inhibitors.
In conclusion, these findings indicate that β2-AR/NF-κB crosstalk promotes potent transcriptional synergy for a subset of NF-κB target genes, including IL-6 and several chemokines. This synergy is apparent in multiple relevant cell types, suggesting it might have general significance. As IL-6 has been attributed with devastating properties in inflammatory disease, and as β-agonists are mainstream therapy for respiratory disease, our data warrant further investigation into the outcome of β2- AR/NF-κB crosstalk in vivo
Beyond diagnosis : early antiretroviral treatment and HIV immunopathogenesis in a Belgian acute HIV infection cohort
No full textVariations 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
Dispelling 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
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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