1,721,004 research outputs found

    Birch, Brian J.

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    Do patients with a history of pre-eclampsia have elevated levels of coagulation and angiogenic markers postpartum?

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    Background: Pre-eclampsia (P-EC) is a pregnancy-specific disorder, characterised by placental insufficiency and endothelial dysfunction. It is a significant cause of maternal and fetal morbidity. Women with a history of P-EC have heightened risks of future cardiovascular and thromboembolic disease. In addition, pre-eclamptic patients have elevated levels of clotting and angiogenic factors; however it is unclear whether these changes persist postpartum. Aims: The aim of this study was to investigate the relationship between haemostatic as well as angiogenic and anti-angiogenic factors in women with a past-history of P-EC, including vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng), in combination with tissue factor (TF) and TF pathway inhibitor (TFPI), also whether these factors were altered postpartum in women with a history of P-EC. Methods: The study followed a case-control design. Blood samples were obtained at 6-12 months postpartum from 21 primiparous women after a pregnancy affected by P-EC, and 21 women with a previously unaffected pregnancy. Plasma concentrations of each of the factors were determined using enzyme-linked immunosorbent assay. Results: Significant differences were not observed in levels of VEGF (p=0.068), PlGF (p=0.333), sFlt-1 (p=0.910), sEng (p=0.612), TF (p=0.260) or TFPI (p=0.786) between women with and without a history of pre-eclampsia. Additionally, no significant difference was found in the TF: TFPI ratio between case and control groups (p=0.734). Conclusion: This study does not support the hypothesis that levels of VEGF, PlGF, sFlt-1, sEng, TF or TFPI are altered in women with a history of P-EC compared to controls. However, we observed a weak positive association between all parameters measured. While we acknowledge that this is a pilot study and that the sample sizes is relatively small, our results suggest that circulating haemostatic, angiogenic and anti-angiogenic factors are not significantly altered in women with a past-history of P-E

    Artemisinins as potential anticancer agents:uptake detection in erythrocytes using Fourier transform infrared spectroscopy and cytotoxicity against bladder cancer cells

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    AimsSemisynthetic derivatives of the antimalarial drug artemisinin may also possess anticancer properties. The ability to detect artemisinin uptake and distribution in cells would facilitate live cell imaging without labelling. This study describes mid-range infrared absorption spectra for three artemisinin variants and attempts to detect their presence in a simple cell model (erythrocytes). Cytotoxicity assays assess potential anticancer properties against bladder cancer cells.MethodsMid-range Fourier transform infrared spectra were obtained from dry preparations of dihydroartemisinin (DHA), artesunate (ART) and artemether (ARTE). Erythrocytes were prepared from normal blood and incubated for 30?min at 37°C with the three artemisinin derivatives. Cytospin preparations were prepared on aluminium foil for spectroscopy. Potential for growth inhibition in the RT112 bladder carcinoma cell line was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide residual viable biomass method.ResultsSpectra were obtained from the three native compounds. Repeat scans after 8?weeks showed ART and ARTE to be stable, stored under manufacturer's recommendations. DHA exhibited marked changes over the same period. It was possible by subtraction to detect DHA in cytospins, but not ART or ARTE. The fit between the subtraction spectrum and that of the native compound was >80%. DHA and ART showed strong cytotoxic potential against RT112 cells.ConclusionsThe artemisinin derivatives tested exhibit unique mid-range infrared absorption spectra which can be used to monitor degradation and, for DHA, can be detected by subtraction in loaded erythrocytes rendering future imaging studies feasible. Its cytotoxic efficacy against RT112 cells suggests bladder cancer as a possible target disease

    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

    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
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