1,720,956 research outputs found
The limitations of coronary angiography: identification of a critical coronary stenosis using intravascular ultrasound
No full textCoronary angiography is considered the gold standard method of imaging coronary stenoses. Quantitative coronary angiography (QCA) has helped to provide information about the degree of stenosis which is used as a surrogate to indicate impaired flow in a coronary bed. QCA however can underestimate disease severity. In this case intravascular ultrasound identifies a critical coronary stenosis not seen on angiography
Thromboelastography: potential bedside tool to assess the effects of antiplatelet therapy?
No full textModified thrombelastography (TEG) is a simple point of care test that provides an overall assessment of ex vivo clot formation and currently has limited clinical application. We evaluated the ability of TEG to assess the effects of antiplatelet therapy on clot formation using a novel assessment parameter (the area under curve). Forty healthy volunteers were divided into four groups of 10. Group A took aspirin 75 mg once daily for 7 days followed by aspirin 75 mg and clopidogrel 75 mg once daily in combination for 7 more days. Blood samples were taken for analysis at day 0 and days 7 and 14. Group B took a single 300 mg dose of aspirin. Group C took 600 mg of clopidogrel only. Group D took 300 mg of aspirin and 600 mg of clopidogrel at the same time. For groups B, C and D blood was taken prior to drug administration and at 2, 6 and 24 h afterwards. Each sample was tested by TEG in four channels following activation using (1) kaolin, (2) activator F (Act F), a direct activator of fibrin, (3) Act F + arachidonic acid (AA) and (4) Act F + adenosine diphosphate (ADP). Parameters measured included the maximum amplitude (MA) of the clot and the area under the TEG-generated curve at 1 h. Significant, time-dependent reductions in MA and area were seen in the AA-activated samples following administration of aspirin in all groups as compared to baseline. By contrast, there were no significant differences in MA or area in the AA-activated samples with clopidogrel alone. Significant reductions were also seen in MA and area in ADP-activated samples from volunteers treated with clopidogrel as compared to baseline. Three out of 10 subjects receiving 600 mg clopidogrel had a reduction in their responses of 30% or less, thus identifying them as relatively resistant to the drug. This study identifies a rapid, reliable method for assessing the time-dependent effects of antiplatelet therapy on clotting using a novel parameter of area of the TEG trace, which could have an important clinical application as a point of care test of efficacy, particularly in the context of acute coronary syndromes and percutaneous coronary intervention
Thrombelastography: current clinical applications and its potential role in interventional cardiology
No full textThrombelastography is a bedside blood test used to assess patients' haemostatic status. It has a well-established role in hepatobiliary and cardiac surgery and is also used in obstetrics and trauma medicine to assess coagulation and identify the causes of post-operative bleeding. It is not routinely used in the diagnosis or treatment of thrombosis although recently it has been shown to predict thrombotic events post-operatively and after percutaneous intervention (PCI). In cardiovascular medicine the importance of the platelet in the pathophysiology of vascular events is increasingly apparent. As a result antiplatelet therapy is a cornerstone of the treatment for coronary disease, particularly in the setting of acute coronary syndromes. The increasing utilization of stents, particularly drug-eluting devices, in PCI has also necessitated widespread use of antiplatelet agents to minimize the risk of stent thrombosis. A quick, accurate and reliable test to measure the effect of platelet inhibition by antiplatelet agents on clotting in an individual patient would be of profound clinical value. The results from such a test could provide prognostic information, allow treatment with antiplatelet agents to be tailored to the individual and identify resistance to one or more of these agents. Optimization and tailoring of anti-platelet therapy in patients with cardiovascular disease, particularly those undergoing PCI, using such a test may reduce morbidity and mortality from thrombotic and haemorrhagic complications. Current methods of assessing platelet activity measure platelet count and function in isolation. Optical aggregation is the most widely used method for assessing platelet function but it is relatively time consuming, measures platelet function in isolation rather than in the context of clot formation and is not a bedside test. By contrast the modified thrombelastograph platelet mapping kit marketed by Haemoscope can be used to assess the effects of antiplatelet agents on ex vivo blood clotting, thus giving a measurement more relevant to in vivo responses. This represents a potentially powerful tool to assess response of individual patients to antiplatelet therapy, particularly in the context of PCI
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
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
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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