282 research outputs found

    Development of a Web System-based Geographic Information System Technologies to Mapping Electromagnetic Fields: First Developments

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    The purpose of this research work is to make decisions about the exposure levels of people to radiation, for which, the Web System based on GIS technology (DECOMAPS) was developed for mapping electromagnetic fields in the city of Riobamba. This system executes analysis, search, creation, automation of processes, and mapping activities of electromagnetic fields. The system was developed on an agile development methodology called SCRUM, which allows to create an optimal and interactive work environment between the product owner and the developers in order to create a quality system. Many technological tools were applied by the developer of this system. Once successfully completed, the system was subjected to tests of functionality and usability of the final product through quality metrics established by ISO 9126-3, where it was determined that the system is 93.64% functional, in addition to a 94.40% in usability. Concluding that the system is functional and can be implemented as a contribution in research to be developed in the future on the effects of electromagnetic fields on the human body.     Keywords: OpenGeo Suite, Java, SCRUM, ISO 9126-3, DECOMAP

    Comparison of four methods to assess high-on platelet reactivity under P2Y12 receptor inhibitor

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    P2Y12 receptor inhibitors are antiplatelet agents commonly prescribed in the treatment of coronary artery disease. Their efficacy can be limited by high on-treatment platelet reactivity (HPR), which can be evaluated by different biological assays. Most commonly, HPR is evaluated by flow cytometric vasodilator-stimulated phosphoprotein-phosphorylation (VASP-P) assay, which can be time consuming. To evaluate the potential interest of novel technologies, we compared four different assays. Ninety patients receiving P2Y12 inhibitors were included. Four technologies were evaluated: the current standard test measuring VASP-P by flow cytometry, the historical reference test based on light transmittance aggregation (LTA), and two relatively novel techniques: whole blood multiple electrode aggregometry (MEA) and platelet function analyzer (PFA), which are less time consuming. The three latter tests were compared with the VASP-P assay as a reference using receiver operating characteristics (ROC) analysis: LTA has an excellent comparability with the VASP test (ROC AUC > 0.9); the other two tests (multiplate and PFA) have only satisfactory comparability (ROC AUC around 0.7) and therefore may not replace the VASP "gold standard" test, if importance is attached to a quantitative assessment of the substitution parameter of VASP. Nevertheless, if a binary approach of the anti-aggregation result is sought, then one can conclude that the three tests are equivalent since Cohen\u27s kappa coefficients are very close for the three tests (k = 0.548 for LTA; k = 0.554 for MEA; k = 0.570 for PFA/P2Y), and a similar proportion of patients are misclassified (15% for LTA, 14% for MEA, and 13.6% for PFA). Discriminant factor analysis using all the parameters provided by each test did not improve the diagnostic performance of MEA or PFA. In conclusion, only LTA shows a good comparability to the VASP assay using ROC curve analysis, probably because misclassified patients have results close to the cutoff values. All three tests have moderate agreement regarding the classification of patients as responders to P2Y12 inhibition

    Multidetector computed tomography angiography for assessment of in-stent restenosis: meta-analysis of diagnostic performance

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    <p>Abstract</p> <p>Background</p> <p>Multi-detector computed tomography angiography (MDCTA)of the coronary arteries after stenting has been evaluated in multiple studies.</p> <p>The purpose of this study was to perform a structured review and meta-analysis of the diagnostic performance of MDCTA for the detection of in-stent restenosis in the coronary arteries.</p> <p>Methods</p> <p>A Pubmed and manual search of the literature on in-stent restenosis (ISR) detected on MDCTA compared with conventional coronary angiography (CA) was performed. Bivariate summary receiver operating curve (SROC) analysis, with calculation of summary estimates was done on a stent and patient basis. In addition, the influence of study characteristics on diagnostic performance and number of non-assessable segments (NAP) was investigated with logistic meta-regression.</p> <p>Results</p> <p>Fourteen studies were included. On a stent basis, Pooled sensitivity and specificity were 0.82(0.72–0.89) and 0.91 (0.83–0.96). Pooled negative likelihood ratio and positive likelihood ratio were 0.20 (0.13–0.32) and 9.34 (4.68–18.62) respectively. The exclusion of non-assessable stents and the strut thickness of the stents had an influence on the diagnostic performance. The proportion of non-assessable stents was influenced by the number of detectors, stent diameter, strut thickness and the use of an edge-enhancing kernel.</p> <p>Conclusion</p> <p>The sensitivity of MDTCA for the detection of in-stent stenosis is insufficient to use this test to select patients for further invasive testing as with this strategy around 20% of the patients with in-stent stenosis would be missed. Further improvement of scanner technology is needed before it can be recommended as a triage instrument in practice. In addition, the number of non-assessable stents is also high.</p

    Revisiting Sex Equality With Transcatheter Aortic Valve Replacement Outcomes A Collaborative, Patient-Level Meta-Analysis of 11,310 Patients

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    AbstractBackgroundThere has been conflicting clinical evidence as to the influence of female sex on outcomes after transcatheter aortic valve replacement.ObjectivesThe aim of this study was to evaluate the impact of sex on early and late mortality and safety end points after transcatheter aortic valve replacement using a collaborative meta-analysis of patient-level data.MethodsFrom the MEDLINE, Embase, and the Cochrane Library databases, data were obtained from 5 studies, and a database containing individual patient-level time-to-event data was generated from the registry of each selected study. The primary outcome of interest was all-cause mortality. The safety end point was the combined 30-day safety end points of major vascular complications, bleeding events, and stroke, as defined by the Valve Academic Research Consortium when available.ResultsFive studies and their ongoing registry data, comprising 11,310 patients, were included. Women constituted 48.6% of the cohort and had fewer comorbidities than men. Women had a higher rate of major vascular complications (6.3% vs. 3.4%; p < 0.001), major bleeding events (10.5% vs. 8.5%; p = 0.003), and stroke (4.4% vs. 3.6%; p = 0.029) but a lower rate of significant aortic incompetence (grade ≥2; 19.4% vs. 24.5%; p < 0.001). There were no differences in procedural and 30-day mortality between women and men (2.6 % vs. 2.2% [p = 0.24] and 6.5% vs. 6.5% [p = 0.93], respectively), but female sex was independently associated with improved survival at median follow-up of 387 days (interquartile range: 192 to 730 days) from the index procedure (adjusted hazard ratio: 0.79; 95% confidence interval: 0.73 to 0.86; p = 0.001).ConclusionsAlthough women experience more bleeding events, as well as vascular and stroke complications, female sex is an independent predictor of late survival after transcatheter aortic valve replacement. This should be taken into account during patient selection for this procedure

    Photoperiod affects the phenotype of mitochondrial complex I mutants

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    Plant mutants for genes encoding subunits of mitochondrial Complex I (CI, NADH:ubiquinone oxidoreductase), the first enzyme of the respiratory chain, display various phenotypes depending on growth conditions. Here, we examined the impact of photoperiod, a major environmental factor controlling plant development, on two Arabidopsis thaliana CI mutants: a new insertion mutant interrupted in both ndufs8.1 and ndufs8.2 genes encoding the NDUFS8 subunit, and the previously characterized ndufs4 CI mutant. In long day (LD) condition, both ndufs8.1 and ndufs8.2 single mutants were indistinguishable from Col-0 at phenotypic and biochemical levels, whereas the ndufs8.1 ndufs8.2 double mutant was devoid of detectable holo-CI assembly/activity, showed higher AOX content/activity and displayed a growth-retardation phenotype similar to that of the ndufs4 mutant. Although growth was more affected in ndufs4 than ndufs8.1 ndufs8.2 under short day (SD) condition, both mutants displayed a similar impairment of growth acceleration after transfer to LD as compared to the WT. Untargeted and targeted metabolomics showed that overall metabolism was less responsive to the SD-to-LD transition in mutants than in the WT. The typical LD acclimation of carbon, nitrogen-assimilation and redox-related parameters was not observed in ndufs8.1 ndufs8. Similarly, NAD(H) content, that was higher in SD condition in both mutants than in Col-0, did not adjust under LD. We propose that altered redox homeostasis and NAD(H) content/redox state control the phenotype of Complex I mutants and photoperiod acclimation in Arabidopsis

    Single high-dose erythropoietin administration immediately after reperfusion in patients with ST-segment elevation myocardial infarction: results of the Erythropoietin in Myocardial Infarction Trial

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    Background Preclinical studies and pilot clinical trials have shown that high-dose erythropoietin (EPO) reduces infarct size in acute myocardial infarction. We investigated whether a single high-dose of EPO administered immediately after reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) would limit infarct size. Methods A total of 110 patients undergoing successful primary coronary intervention for a first STEMI was randomized to receive standard care either alone (n = 57) or combined with intravenous administration of 1,000 U/kg of epoetin β immediately after reperfusion (n = 53). The primary end point was infarct size assessed by gadolinium-enhanced cardiac magnetic resonance after 3 months. Secondary end points included left ventricular (LV) volume and function at 5-day and 3-month follow-up, incidence of microvascular obstruction (MVO), and safety. Results Erythropoietin significantly decreased the incidence of MVO (43.4% vs 65.3% in the control group, P = .03) and reduced LV volume, mass, and function impairment at 5-day follow-up (all P &lt; .05). After 3 months, median infarct size (interquartile range) was 17.5 g (7.6-26.1 g) in the EPO group and 16.0 g (9.4-28.2 g) in the control group (P = .64); LV mass, volume, and function were not significantly different between the 2 groups. The same number of major adverse cardiac events occurred in both groups. Conclusions Single high-dose EPO administered immediately after successful reperfusion in patients with STEMI did not reduce infarct size at 3-month follow-up. However, this regimen decreased the incidence of MVO and was associated with transient favorable effects on LV volume and function

    Accuracy of dual-source CT coronary angiography: first experience in a high pre-test probability population without heart rate control

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    The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography (DSCT) for evaluation of coronary artery disease (CAD) in a population with extensive coronary calcifications without heart rate control. Thirty patients (24 male, 6 female, mean age 63.1±11.3 years) with a high pre-test probability of CAD underwent DSCT coronary angiography and invasive coronary angiography (ICA) within 14±9 days. No beta-blockers were administered prior to the scan. Two readers independently assessed image quality of all coronary segments with a diameter ≥1.5 mm using a four-point score (1: excellent to 4: not assessable) and qualitatively assessed significant stenoses as narrowing of the luminal diameter >50%. Causes of false-positive (FP) and false-negative (FN) ratings were assigned to calcifications or motion artifacts. ICA was considered the standard of reference. Mean body mass index was 28.3±3.9 kg/m(2) (range 22.4–36.3 kg/m(2)), mean heart rate during CT was 70.3±14.2 bpm (range 47–102 bpm), and mean Agatston score was 821±904 (range 0–3,110). Image quality was diagnostic (scores 1–3) in 98.6% (414/420) of segments (mean image quality score 1.68±0.75); six segments in three patients were considered not assessable (1.4%). DSCT correctly identified 54 of 56 significant coronary stenoses. Severe calcifications accounted for false ratings in nine segments (eight FP/one FN) and motion artifacts in two segments (one FP/one FN). Overall sensitivity, specificity, positive and negative predictive value for evaluating CAD were 96.4, 97.5, 85.7, and 99.4%, respectively. First experience indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD in a high pre-test probability population with extensive coronary calcifications and without heart rate control

    Visualization of elusive structures using intracardiac echocardiography: Insights from electrophysiology

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    Electrophysiological mapping and ablation techniques are increasingly used to diagnose and treat many types of supraventricular and ventricular tachycardias. These procedures require an intimate knowledge of intracardiac anatomy and their use has led to a renewed interest in visualization of specific structures. This has required collaborative efforts from imaging as well as electrophysiology experts. Classical imaging techniques may be unable to visualize structures involved in arrhythmia mechanisms and therapy. Novel methods, such as intracardiac echocardiography and three-dimensional echocardiography, have been refined and these technological improvements have opened new perspectives for more effective and accurate imaging during electrophysiology procedures. Concurrently, visualization of these structures noticeably improved our ability to identify intracardiac structures. The aim of this review is to provide electrophysiologists with an overview of recent insights into the structure of the heart obtained with intracardiac echocardiography and to indicate to the echo-specialist which structures are potentially important for the electrophysiologist
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