1,720,957 research outputs found

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    α-Ketoglutarate-related inhibitors of HIF prolyl hydroxylases are substrates of renal organic anion transporters 1 (OAT1) and 4 (OAT4)

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    2-Oxoglutarate or alpha-ketoglutarate (alpha KG) is a substrate of HIF prolyl hydroxylases 1-3 that decrease cellular levels of the hypoxia-inducible factor 1 alpha (HIF-1 alpha) in the presence of oxygen. alpha KG analogs are applied to stabilize HIF-1 alpha even in the presence of oxygen and thus provide a novel therapeutic option in treating kidney diseases. In the kidneys, the organic anion transporters 1 and 3 (OAT1 and OAT3, respectively) in cooperation with the sodium-dependent dicarboxylate transporter 3 (NaDC3) and the OAT4 might be responsible for the uptake of alpha KG analogs into and the efflux out of the tubular cells. Using the radiolabelled substrates p-aminohippurate (PAH, OAT1), estrone-3-sulfate (ES; OAT3, OAT4), and succinate (NaDC3), N-oxalylglycine (NOG), dimethyloxalyl glycine (DMOG), 2,4-diethylpyridine dicarboxylate (2,4-DPD), and pyridine-2,4-dicarboxylic acid (PDCA) were tested in cis-inhibition and trans-stimulation experiments. None of these alpha KG analogs interacted with NaDC3. 2,4-DPD and PDCA inhibited ES uptake by OAT3 moderately. NOG, 2,4-DPD and PDCA, but not DMOG, inhibited PAH uptake by OAT1 significantly. trans-Stimulation experiments and experiments demonstrating stabilization of HIF-1 alpha revealed that NOG and PDCA, but not 2,4-DPD, are translocated by OAT1. All compounds trans-stimulated ES uptake by OAT4, but only PDCA stabilized HIF-1 alpha. The data suggest that OAT1 is involved in the uptake of NOG and PDCA across the basolateral membrane of proximal tubule cells, whereas OAT4 may release these compounds into the primary urine.German Research Council [BU998/5-1

    Variations on the Author

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    “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

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    We 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

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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

    Selective Stabilization of HIF-1 alpha in Renal Tubular Cells by 2-Oxoglutarate Analogues

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    The role of proximal versus distal tubular injury in the pathogenesis of acute kidney injury (AM) is debatable. Inhibition of prolyl hydroxylases that regulate the degradation of hypoxia-inducible transcription factors (HIFs) is a promising therapeutic approach to optimize energy preservation under hypoxia and has successfully been applied to protect kidney structure and function in AKI models. Presently used prolyl hydroxylase inhibitors are lipophilic 2-oxoglutarate analogues (2OGAs) that are widely taken up in cells of most organs. Given the selective expression of organic anion transporters (OATs) in renal proximal tubular cells, we hypothesized that hydrophilic 2OGAs can specifically target proximal tubular cells. We found that cellular hydrophilic 2OGAs uptake depended on OATs and largely confined to the kidney, where it resulted in activation of HIF target genes only in proximal tubular cells. When applied in ischemia-reperfusion experiments, systemically active 2OGA preserved kidney structure and function, but OAT1-transported 2OGA was not protective, suggesting that HIT stabilization in distal tubular rather than proximal tubular cells and/or nontubular cells mediates protective effects. This study provides proof of concept for selective drug targeting of proximal tubular cells on the basis of specific transporters, gives insights into the role of different nephron segments in AKI pathophysiology, and may offer options for long-term HIF stabilization in proximal tubules without confounding effects of erythropoietin induction in peritubular cells and unwarranted extrarenal effects. (Am J Pathol 2012, 181:1595-160 http://dx.doi.org/10.1016/j.ajpath.2012.07.010
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