26 research outputs found

    The Compact Linear Collider (CLIC) - 2018 Summary Report

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    Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

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    We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

    The Compact Linear Collider (CLIC) - 2018 Summary Report

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    The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear e+ee^+e^- collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years

    Optimum coupling of photovoltaic devices and Peltier coolers for improved performance and stability

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    Photovoltaics (PV) have admittedly seen substantial advancements during the last decades. Improvements in the performance of conventional technologies as well as the emergence of cost effective alternatives facilitated its establishment as a major contributor towards the adoption of a green power production model. Nevertheless, photovoltaics still suffer from efficiency issues, mainly related to performance dependency upon operating temperature. For perovskite cells, it is also crucial to maintain temperature below a defined threshold to avoid premature degradation. Photovoltaic-thermoelectric hybridization has been recently proposed as a means of restricting excessive temperature increase, reducing recombination and improving the overall efficiency response. In this work, the performance of a hybrid photovoltaic-Peltier system is examined through an analytical modelling approach. Different thermoelectric coolers (TECs) and PV cell types have been studied. Furthermore, a sensitivity analysis has been conducted in order to identify the most critical parameters for obtaining optimum coupling between PV and TEC technologies

    Clinical characteristics of COVID-19 in neonates and young infants

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    We report the clinical characteristics and management of fourteen neonates and very young infants with COVID-19. Although all presented with mild symptoms and did not require specific treatment, most of them had abnormal laboratory and radiological findings. Ten infants presented with neutropenia and/or monocytosis but none with lymphopenia. Transient hypertriglyceridemia and/or prolonged viral shedding were detected in 9 patients. Conclusion: Based to our experience, COVID-19 is mild in very young infants and might have distinct laboratory findings.What is Known:• SARS-CoV-2 in infants is a mild disease.• The period of transmission is approximately 2 weeks.What is New:• Very young age is not a risk factor for severe COVID-19 but could be associated with prolonged viral shedding.• Neutropenia and monocytosis are distinct characteristics of COVID-19 in very young infants. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature

    Study of the Thermo-Mechanical Behavior of the CLIC Two-Beam Modules

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    The final luminosity target of the Compact LInear Collider (CLIC) imposes a micron-level stability requirement on the two-meter repetitive two-beam modules constituting the main linacs. Two-beam prototype modules are being assembled to extensively study their thermo-mechanical behaviour under different operation modes. The power dissipation occurring in the modules will be reproduced and the efficiency of the corresponding cooling systems validated. At the same time, the real environmental conditions present in the CLIC tunnel will be studied. Air conditioning and ventilation systems have been installed in the dedicated laboratory. The air temperature will be changed from 20 to 40°C, while the air flow rate will be varied up to 0.8 m/s. During all experimental tests, the alignment of the RF structures will be monitored to investigate the influence of power dissipation and air temperature on the overall thermo-mechanical behaviour. \nThis test program will allow for better understanding the behaviour of the CLIC modules and the results will be propagated back both to the numerical modelling and the engineering design

    Effect of cryoballoon and radiofrequency ablation for pulmonary vein isolation on left atrial function in patients with nonvalvular paroxysmal atrial fibrillation: A prospective randomized study (Cryo-LAEF study)

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    Background: Isolation of the pulmonary veins (PVI) has become a mainstay in atrial fibrillation (AFib) therapy. Lesions in left atrial tissue lead to scar formation and this may affect left atrial function. Methods: Patients with paroxysmal AFib were randomly assigned in a 1:2 allocation scheme to radiofrequency (RF) ablation or cryoballoon. Real-time three-dimensional echocardiography was performed (under sinus rhythm in all cases) before ablation and at 1 and 3 months to evaluate the left atrial functional indices. The primary outcome measure was change in left atrial ejection fraction (LAEF) at 1 month. Results: 120 patients were randomized (80 to cryoballoon, 40 to RF). The absolute change in LAEF at 1 month was 4.0 (Q1-Q3, −0.1to 7.6)% in the cryoballoon group and −0.8 (Q1-Q3, −1.9 to 0.9)% in the RF group (P < 0.001 for the comparison between groups). At 3 months, the corresponding changes were 6.7 (Q1-Q3, 3.4-11.2)% and 0.7 (Q1-Q3, −0.7 to 3.5)%, respectively (P < 0.001). Overall, the rate of patients with lower LAEF at 3 months compared to baseline was 2.5% in the cryoballoon group and 32.5% in the RF group (P < 0.001). AFib recurrence rate at 6 months was higher in patients with decreased LAEF (odds ratio, 6.2; 95% confidence interval, 2.0-19.5; P = 0.002). Conclusion: The Cryo-LAEF study prospectively compared the effects of RF and cryoballoon ablation on left atrial function. Both at 1 and 3 months postablation, LAEF was either improved or stable in both ablation groups. © 2019 Wiley Periodicals, Inc

    Biomarkers determining prognosis of atrial fibrillation ablation

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    Catheter ablation for rhythm control is recommended in specific patient populations with paroxysmal, persistent, or long-standing persistent atrial fibrillation. Pulmonary vein isolation is the cornerstone of the ablative therapy for atrial fibrillation. However, relapse is still common since the single procedure efficacy of atrial fibrillation ablation was estimated to be 60-80% in paroxysmal and 50-70% in persistent atrial fibrillation. It is important to identify predictors of successful atrial fibrillation patients ablation. In the present review, we will assess the role of available biomarkers to predict responders of an initial atrial fibrillation catheter ablation. Emphasis has been given on the role of myocardial injury biomarkers, natriuretic peptides and traditional inflammatory markers. Novel inflammatory markers, oxidative stress biomarkers and microRNAs have also been examined as predictors of a successful atrial fibrillation procedure. Notably, the impact of procedural and short-term administration of steroids, as well as the role of colchicine on preventing atrial fibrillation recurrence after ablation is thoroughly presented. © 2019, Bentham Science Publishers B.V.. All rights reserved

    Effect of pulmonary vein isolation on left atrial appendage flow in paroxysmal atrial fibrillation

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    Background: Left atrial appendage (LAA) functional modification in the context of pulmonary vein isolation has been a focus point of research and LAA emptying flow velocity (LAAEFV) is considered to reflect LAA contractility, stunning, and fibrosis. Objective: In the present study, we sought to prospectively evaluate short-term LAAEFV changes after radiofrequency (RF) or cryoballoon ablation in paroxysmal AF. Methods: This was a prospective substudy of the Effect of Cryoballoon and RF Ablation on Left Atrial Function (CryoLAEF) study (ClinicalTrials.gov Identifier: NCT02611869). Thirty patients, randomly assigned to RF or cryoablation, were prospectively followed. Transesophageal echocardiograms were performed at baseline and at 3 months postablation to measure LAAEFV. Results: All measurements were performed in sinus rhythm. Overall, LAAEFV was 44.2 [38.5–62.8] cm/s at baseline and was increased to 70.8 [64.8–77.6] cm/s at 3 months’ postablation (P < 0.001). Baseline LAAEFV was 52.5 [37.7–68.0] cm/s in the RF group and 42.8 [38.7–52.9] cm/s in the CryoBalloon group (P = 0.653). At 3 months, the corresponding values were 68.5 [61.9–76.6] cm/s and 73.9 [69.2–79.9] cm/s, respectively (P = 0.081 for the difference between the two groups at 3 months). The median change in LAAEFV was 11.0 [4.7–26.2] cm/s in the RF group versus 29.6 [15.8–37.0] cm/s in the CryoBalloon group (P = 0.033). Conclusion: LAA function is improved after catheter ablation with RF or balloon cryoablation in patients with paroxysmal AF, evaluated while in sinus rhythm both at baseline and on follow-up. © 2018 Wiley Periodicals, Inc

    Laboratory investigation and phylogenetic analysis of an imported Middle East respiratory syndrome coronavirus case in Greece.

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    Rapid and reliable laboratory diagnosis of persons suspected of Middle East respiratory syndrome coronavirus (MERS-CoV) infection is important for timely implementation of infection control practices and disease management. In addition, monitoring molecular changes in the virus can help elucidate chains of transmission and identify mutations that might influence virus transmission efficiency. This was illustrated by a recent laboratory investigation we conducted on an imported MERS-CoV case in Greece. Two oropharyngeal swab specimens were collected on the 1st and 2nd day of patient hospitalization and tested using two real-time RT-PCR (rRT-PCR) assays targeting the UpE and Orf-1a regions of the MERS-CoV genome and RT-PCR and partial sequencing of RNA-dependent RNA polymerase and nucleocapsid genes. Serum specimens were also collected and serological test were performed. Results from the first swab sample were inconclusive while the second swab was strongly positive for MERS-CoV RNA by rRT-PCR and confirmed positive by RT-PCR and partial gene sequencing. Positive serologic test results further confirmed MERS-CoV infection. Full-length nucleocapsid and spike gene coding sequences were later obtained from the positive swab sample. Phylogenetic analysis revealed that the virus was closely related to recent human-derived MERS-CoV strains obtained in Jeddah and Makkah, Saudi Arabia, in April 2014 and dromedary camels in Saudi Arabia and Qatar. These findings were consistent with the patient's history. We also identified a unique amino acid substitution in the spike receptor binding domain that may have implications for receptor binding efficiency. Our initial inconclusive rRT-PCR results highlight the importance of collecting multiple specimens from suspect MERS-CoV cases and particularly specimens from the lower respiratory tract
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