189 research outputs found
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Interaction of a free burning arc with regenerative protective layers
The possible use of protective layers made of ceramic powders for walls in thermal plasma applications is studied. A stable free burning arc of currents up to 5 kA between copper- tungsten electrodes is used to analyse the arc interaction with samples coated by mixtures of CaCO3, MgCO3, and Mg(OH)2 with plaster. By means of optical emission spectroscopy the maximum arc temperature and the radiation impact on the surfaces are estimated to be around 15000 K and 20 MWm-2, respectively. Thermographic measurements confirm the efficient protection of substrates by all layer materials. Layers containing CaCO3 lead to the lowest heating of ceramic samples which may be caused by a strong evaporation of the layer material
A Case Study on Formal Verification of Self-Adaptive Behaviors in a Decentralized System
Self-adaptation is a promising approach to manage the complexity of modern
software systems. A self-adaptive system is able to adapt autonomously to
internal dynamics and changing conditions in the environment to achieve
particular quality goals. Our particular interest is in decentralized
self-adaptive systems, in which central control of adaptation is not an option.
One important challenge in self-adaptive systems, in particular those with
decentralized control of adaptation, is to provide guarantees about the
intended runtime qualities. In this paper, we present a case study in which we
use model checking to verify behavioral properties of a decentralized
self-adaptive system. Concretely, we contribute with a formalized architecture
model of a decentralized traffic monitoring system and prove a number of
self-adaptation properties for flexibility and robustness. To model the main
processes in the system we use timed automata, and for the specification of the
required properties we use timed computation tree logic. We use the Uppaal tool
to specify the system and verify the flexibility and robustness properties.Comment: In Proceedings FOCLASA 2012, arXiv:1208.432
Evaluation of maternal antibody levels for establishing the vaccination program against Newcastle disease in ostrich chicks
ABSTRACT Newcastle disease virus (NDV) is known as one of the most important endemic viral pathogen for various avian species such as ostrich, in Iran. Therefore, establishing a routine vaccination program against ND in ostrich flocks would be useful in order to reduce the danger of this infection. Newcastle disease occurs among the ostriches and leads to high rate of mortality while most of the losses are among the youngest ones. This experiment was designed to follow up the changes of maternal antibody in ostrich chicks during the first weeks of their life. At this point of view, 700 one day old ostrich chicks were monitored and every seven days interval 10 blood samples were taken regularly and the titers of maternal antibody in their sera were studied. The haemagglutination inhibition (HI) test was used to evaluate the amount of anti-ND antibody. After hatching this study followed up to 49 th day. Due to our findings, the day 30 is recommended as a proper time to start the vaccination program against ND in flocks of ostrich chicks with maternal antibody
Investigating The Frequency of Serrated Polyps/Adenomas and Their Subtypes in Colonic Polyp Samples
BACKGROUND: The purpose of this study was to determine the frequency of Serrated polyps of colonic polyps samples in Hazrate Rasoule Akram Hospital over ten years. MATERIALS: The target group in this study was patients with colonic polyps in Hazrate Rasoule Akram Hospital. Pathologic evaluation of these patients was done. Serrated polyps, by location, gender, age and type of polyps were divided and frequency of them were determined separately. RESULTS: Of 381 patients studied, 224 (58.79) and 157(41.20) were males and females, respectively. Mean age of patients was 59.25 years. In initial diagnosis, frequency of Adenomatous polyp, Hyperplastic polyp and Mixed polyp were 92.44 and 5.33, and 2.22, respectively. In final diagnosis (Second evaluation), frequency of Adenomatous polyp, Hyperplastic polyp, Mixed polyp, Sessile Serrated Adenoma/ Polyp, Traditional Serrated Adenoma and SPU (Serrated Polyp Unclassifiable) were 90.44, 4.88, 2.44, 1.11, 0.66 and 0.44, respectively. 72.13 and 27.86 of polyps were low grade dysplasia and high grade dysplasia, respectively. According to the results of this study, the incidence of all types of polyps detected was more in men than women. Rectum and sigmoid were most abundant in the area polyp in both initial and final diagnosis. CONCLUSION: Despite the low prevalence of Serrated polyps in patients, early diagnosis is the best action to reduce morbidity and mortality. Probability of the risk of progression from low grade to high grade dysplasia and transforming into Adenocarcinoma is high in Serrated polyps
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Arrhythmic risk profile and outcomes of patients undergoing cardiac sympathetic denervation for recurrent monomorphic ventricular tachycardia after ablation
Background Cardiac sympathetic denervation (CSD) has been used as a bailout strategy for refractory ventricular tachycardia (VT). Risk of VT recurrence in patients with scar-related monomorphic VT referred for CSD and the extent to which CSD can modify this risk is unknown. We aimed to quantify arrhythmia recurrence risk and impact of CSD in this population. Methods and Results Adjusted competing risk time to event models were developed to adjust for risk of VT recurrence and sustained VT/implantable cardioverter-defibrillator shocks after VT ablation based on patient comorbidities at the time of VT ablation. Adjusted VT and implantable cardioverter-defibrillator shock recurrence rates were estimated for the subgroup who subsequently required CSD after ablation. The expected adjusted recurrence rates were then compared with the observed rates after CSD. Data from 381 patients with scar-mediated monomorphic VT who underwent VT ablation were analyzed, excluding patients with polymorphic VT. Sixty eight patients underwent CSD for recurrent VT. CSD reduced the expected adjusted VT recurrence rate by 36% (expected rate of 5.61 versus observed rate of 3.58 per 100 person-months, P=0.01) and the sustained VT/implantable cardioverter-defibrillator shock rates by 34% (expected rate of 4.34 versus observed 2.85 per 100 person-months, P=0.03). The median number of sustained VT/implantable cardioverter-defibrillator shocks in the year before versus the year after CSD was reduced by 90% (10 versus 1, P<0.0001). Conclusions Patients referred for CSD for refractory scar-mediated monomorphic VT are at a higher risk of VT recurrence after ablation as compared with those not requiring CSD, mostly because of their cardiac comorbidities. CSD significantly reduced both the expected risk of recurrences and VT burden
Esophageal cooling for protection during left atrial ablation: a systematic review and meta-analysis.
PURPOSE: Thermal damage to the esophagus is a risk from radiofrequency (RF) ablation of the left atrium for the treatment of atrial fibrillation (AF). The most extreme type of thermal injury results in atrio-esophageal fistula (AEF) and a correspondingly high mortality rate. Various strategies for reducing esophageal injury have been developed, including power reduction, esophageal deviation, and esophageal cooling. One method of esophageal cooling involves the direct instillation of cold water or saline into the esophagus during RF ablation. Although this method provides limited heat-extraction capacity, studies of it have suggested potential benefit. We sought to perform a meta-analysis of published studies evaluating the use of esophageal cooling via direct liquid instillation for the reduction of thermal injury during RF ablation. METHODS: We searched PubMed for studies that used esophageal cooling to protect the esophagus from thermal injury during RF ablation. We then performed a meta-analysis using a random effects model to calculate estimated effect size with 95% confidence intervals, with an outcome of esophageal lesions stratified by severity, as determined by post-procedure endoscopy. RESULTS: A total of 9 studies were identified and reviewed. After excluding preclinical and mathematical model studies, 3 were included in the meta-analysis, totaling 494 patients. Esophageal cooling showed a tendency to shift lesion severity downward, such that total lesions did not show a statistically significant change (OR 0.6, 95% CI 0.15 to 2.38). For high-grade lesions, a significant OR of 0.39 (95% CI 0.17 to 0.89) in favor of esophageal cooling was found, suggesting that esophageal cooling, even with a low-capacity thermal extraction technique, reduces the severity of lesions resulting from RF ablation. CONCLUSIONS: Esophageal cooling reduces the severity of the lesions that may result from RF ablation, even when relatively low heat extraction methods are used, such as the direct instillation of small volumes of cold liquid. Further investigation of this approach is warranted, particularly with higher heat extraction capacity techniques
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NCCN Guidelines Insights: Survivorship, Version 2.2019.
The NCCN Guidelines for Survivorship provide screening, evaluation, and treatment recommendations for consequences of cancer and cancer treatment to aid healthcare professionals who work with survivors of adult-onset cancer. Guidance is also provided to help promote physical activity, weight management, and proper immunizations in survivors and to facilitate care coordination to ensure that all needs are addressed. These NCCN Insights summarize some of the topics discussed by the NCCN Survivorship Panel during the 2019 update of the guidelines, including the survivorship population addressed, ways to improve care coordination, and pain management
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NCCN Guidelines Insights: Survivorship, Version 2.2020.
The NCCN Guidelines for Survivorship provide screening, evaluation, and treatment recommendations for consequences of adult-onset cancer and its treatment, with the goal of helping healthcare professionals who work with survivors, including those in primary care. The guidelines also provide recommendations to help clinicians promote physical activity, weight management, and proper immunizations in survivors and facilitate care coordination to ensure that all of the survivors needs are addressed. These NCCN Guidelines Insights summarize additions and changes made to the guidelines in 2020 regarding cardiovascular disease risk assessment and screening for subsequent primary malignancies
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