1,720,976 research outputs found
A new method of measure of bubble gas volume shows that interleukin-6 injected into rats has no effect on gas embolism
No full textBondi M, Cavaggioni A, Gasperetti A, Rubini A. A new method of measure of bubble gas volume shows that interleukin-6 injected into rats has no effect on gas embolism. Undersea Hyperb Med 2009 1 36 (2):1031 115. The pleiotropic cytokine interleukin-6 increases in the plasma of rats after an air dive. Interleukin-6 shares both of inflammatory and anti-inflammatory properties and may condition the vascular system and gas embolism after an air dive. Up to now it is not known whether interleukin-6 has an effect on gas embolism. Aim of this work is to study the effect of interleukin-6 on gas embolism after a standard decompression protocol in a rat model. The volume of gas bubbles was measured in the heart cavities with a new method based on the buoyancy of the heart at different pressures which is physically sound, accurate and precise down to 10(-4) cm(3). No effect was found after injecting physiological doses of interleukin-6 at different times before the air dive. The mortality of the rats in the first half hour after the decompression was associated with a substantial gas volume measured in the heart. Multi-variate logistic regression analysis showed that the female rats had a higher risk compared to male rats of developing a substantial bubble volume and of not surviving; the spring-summer season was a risk factor for the survival. Further studies are needed to see whether interleukin-6 in association with other cytokines has ail effect on gas embolism
Coronary CT angiography in asymptomatic middle-aged athletes with ST segment anomalies during maximal exercise test
No full textThe clinical significance of ST segment anomalies occurring during exercise test in asymptomatic subjects is still debated. We designed a cross-sectional study to evaluate if the presence of these exercise test abnormalities were related with coronary CT angiography findings. Nine hundred forty athletes (range 30 to 60 years old), performed a maximal exercise test for sport eligibility. Forty-six subjects (4.9%) showing ST abnormalities during exercise and/or the recovery phase were referred to a 64-slice coronary computed tomography (CT) angiography. Among 44 subjects who underwent coronary CT angiography, 23 had an equivocal while 21 had a positive exercise test. Coronary CT angiography found, six and eight subjects with significant and not significant coronary artery disease, respectively. Further, seven patients demonstrated origin and course coronary anomalies. The positive predictive value for significant coronary artery disease of the exercise test was 13.6%. Our data suggest the referral to coronary CT angiography even of patients with equivocal repolarization anomalies during exercise and its recovery phase. Although the positive predictive value of a maximal exercise test in asymptomatic athletes appears lower than what observed in patients at high risk for coronary artery disease, about half of athletes with equivocal or positive exercise test demonstrated some coronary abnormalities
Inter-arm Systolic Blood Pressure Difference in Physically Active, Adult Subjects
No full textIncreased inter-arm systolic blood pressure difference (ΔPsys) has been associated with cardiovascular (CV) disease in elderly patients with CV risk factors. However, its significance in healthy subjects is unclear
Myocardial Crypt in an Asymptomatic Young Athlete: How to Interpret?
No full textMyocardial crypts are extensions of blood signal penetrating the compact myocardium and are considered in literature as either a distinctive cardiac magnetic resonance (CMR) imaging marker for hypertrophic cardiomyopathy or as benign congenital malformations. What if CMR reveals a myocardial crypt in the presence of an altered ECG in an asymptomatic, enlarged young athlete's heart? The illustrated case demonstrates that new insights in CMR can also require further diagnostic interventions, which might have deleterious consequences for the individual athlete due to the uncertain interpretation of some findings in the demanding new world of a rapidly developing diagnostic imaging technique
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
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