168 results on '"Ulrich Fischer"'
Search Results
2. Does the severity of low-gradient aortic stenosis classified by computed tomography–derived aortic valve calcification determine the outcome of patients after transcatheter aortic valve implantation (TAVI)?
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Ulrich Fischer-Rasokat, Maren Weferling, Won-Keun Kim, Christian W. Hamm, Thomas Walther, Matthias Renker, Mirko Doss, Helge Möllmann, Christoph Liebetrau, and Andreas Rolf
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medicine.medical_specialty ,Severity of Illness Index ,Ventricular Function, Left ,030218 nuclear medicine & medical imaging ,Transcatheter Aortic Valve Replacement ,03 medical and health sciences ,0302 clinical medicine ,Afterload ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Tomography ,Retrospective Studies ,Neuroradiology ,Ejection fraction ,medicine.diagnostic_test ,business.industry ,Stroke Volume ,Interventional radiology ,Aortic Valve Stenosis ,General Medicine ,Stroke volume ,medicine.disease ,Stenosis ,Treatment Outcome ,Aortic Valve ,030220 oncology & carcinogenesis ,Aortic valve stenosis ,Radiology ,Aortic valve calcification ,business - Abstract
Aortic valve calcification (AVC) determined by computed tomography has emerged as a complementary measure of aortic stenosis (AS) severity and as a predictor of adverse events. Thus, AVC can guide further treatment decisions in patients with low-gradient AS (LG-AS). We compared the symptomatic and prognostic outcome of patients with low vs. high AVC after transcatheter aortic valve implantation (TAVI). Patients with an aortic valve area index ≤ 0.6 cm2/m2 and a mean pressure gradient (MPG) 35 ml/m2, LVEF ≥ 50%, n = 244); patients with MPG ≥ 40 mmHg (n = 1142) served as controls. Patients were further categorized according to published AVC thresholds. Demographic characteristics and cardiovascular risk were not different between patients with high vs. low AVC in any of the subgroups. Patients with low AVC had a lower MPG. Symptom improvement at 30 days was observed in the majority of patients but was less pronounced in LFLG-AS patients with low vs. those with high AVC. Kaplan-Meier 1-year survival curves were identical between patients with low and high AVC in all three LG-AS groups. The severity of LG-AS based on AVC has no impact on 1-year prognosis once TAVI has been performed. • Aortic valve calcification (AVC) determined by computed tomography has emerged as a complementary measure of aortic stenosis (AS) severity and is of prognostic value in selected patients. • Patients with inconsistent echocardiographic measures can be classified as having severe or nonsevere AS by the computed tomography–derived AVC score. • The prognostic value of AVC in patients with low-gradient AS is abrogated after correction of afterload by TAVI.
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- 2020
3. Exercise Hemodynamic Profiling Is Associated With Outcome in Patients Undergoing Percutaneous Mitral Valve Repair
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Christoph B. Wiedenroth, Veselin Mitrovic, Christoph Liebetrau, Steffen D. Kriechbaum, Andreas Rieth, Khodr Tello, Elena Wenninger, Henning Gall, Stefan Guth, Hossein Ardeschir Ghofrani, Manuel J. Richter, Christian W. Hamm, Claudia Walther, and Ulrich Fischer-Rasokat
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Heart Valve Prosthesis Implantation ,medicine.medical_specialty ,Mitral regurgitation ,New York Heart Association Class ,Ejection fraction ,business.industry ,Hemodynamics ,Mitral Valve Insufficiency ,medicine.disease ,Treatment Outcome ,medicine.anatomical_structure ,Internal medicine ,Mitral valve ,Heart failure ,Cohort ,medicine ,Cardiology ,Humans ,Mitral Valve ,Cardiac Surgical Procedures ,Cardiology and Cardiovascular Medicine ,business ,Percutaneous Mitral Valve Repair - Abstract
Background: Percutaneous mitral valve repair (PMVR) in high-risk patients is currently controversial, especially in those with secondary mitral regurgitation (MR). Exercise pulmonary hemodynamics may help to unmask cardiac dysfunction as well as the dynamic impact of MR. The present study sought to explore the clinical impact of preprocedural exercise right heart catheterization (RHC) for the selection of patients who could most benefit from PMVR. Methods: Sixty-eight patients with symptomatic primary and secondary MR and exercise RHC before PMVR were included in this retrospective analysis of the association of exercise RHC parameters with survival and improvement in New York Heart Association class within 12 months. Results: Median patient age was 77 years (±8.5), 37% were female, and 81% presented with New York Heart Association class III. A total of 65% of the patients had left ventricular ejection fraction P P Conclusions: In our cohort of patients with indication for PMVR, preprocedural exercise RHC was able to identify patients with an unfavorable outcome. Further studies with larger patient numbers are warranted before this approach can be implemented in a structured diagnostic workup of patients under evaluation for PMVR.
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- 2021
4. Prospective validation of an acoustic-based system for the detection of obstructive coronary artery disease in a high-prevalence population
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Christoph Liebetrau, Oliver Dörr, Samuel Emil Schmidt, Matthias Renker, Steffen D. Kriechbaum, Bjarke Skogstad Larsen, Jan Sebastian Wolter, Ulrich Fischer-Rasokat, Holger Nef, Won-Keun Kim, Timm Bauer, Morten Bøttcher, and C. W. Hamm
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medicine.medical_specialty ,medicine.medical_treatment ,Population ,Coronary Artery Disease ,030204 cardiovascular system & hematology ,Coronary Angiography ,Coronary artery disease ,03 medical and health sciences ,Coronary circulation ,0302 clinical medicine ,Percutaneous Coronary Intervention ,Predictive Value of Tests ,Internal medicine ,medicine ,Prevalence ,Humans ,030212 general & internal medicine ,education ,education.field_of_study ,business.industry ,Coronary Stenosis ,Phonocardiography ,Percutaneous coronary intervention ,Invasive coronary angiography ,Acoustics ,medicine.disease ,Confidence interval ,Cardiac surgery ,Coronary Stenosis/diagnostic imaging ,medicine.anatomical_structure ,Cohort ,Conventional PCI ,Cardiology ,Heart sounds ,Coronary Artery Disease/diagnosis ,Cardiology and Cardiovascular Medicine ,business - Abstract
Recent guidelines recommend a risk-adjusted, non-invasive work-up in patients presenting with chest discomfort to exclude coronary artery disease (CAD). However, a risk-adjusted diagnostic approach remains challenging in clinical practice. An acoustic detection device for analyzing micro-bruits induced by stenosis-generated turbulence in the coronary circulation has shown potential for ruling out CAD in patients with low-to-intermediate likelihood. We examined the diagnostic value of this acoustic detection system in a high-prevalence cohort. In total, 226 patients scheduled for clinically indicated invasive coronary angiography (ICA) were prospectively enrolled at two centers and examined using a portable, acoustic detection system. The acoustic analysis was performed in double-blinded fashion prior to quantitative ICA and following percutaneous coronary intervention (PCI). An acoustic detection result (CAD score) was obtained in 94% of all patients. The mean baseline CAD score was 41.2 ± 11.9 in patients with obstructive CAD and 33.8 ± 13.4 in patients without obstructive CAD (p < 0.001). ROC analysis revealed an AUC of 0.661 (95% CI 0.584–0.737). Sensitivity was 97.6% (95% confidence interval (CI) 91.5–99.7%), specificity was 14.5% (CI 9.0–21.7%), negative predictive value was 90.5% (CI 69.6–98.8%), and positive predictive value was 41.7% (CI 34.6–49.0%). Following PCI, the mean CAD score decreased from 40.5 ± 11.2 to 38.3 ± 13.7 (p = 0.039). Using an acoustic detection device identified individuals with CAD in a high-prevalence cohort with high sensitivity but relatively low specificity. The negative predictive value was within the predicted range and may be of value for a fast rule-out of obstructive CAD even in a high-prevalence population.
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- 2021
5. CMR-derived myocardial strain analysis differentiates ischemic and dilated cardiomyopathy - A propensity score-matched study
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Steffen D. Kriechbaum, Lena Lehmann, Jan Sebastian Wolter, Beatrice von Jeinsen, Christian W. Hamm, C Unbehaun, Till Keller, Andreas Rolf, Andreas Hain, Ulrich Fischer-Rasokat, Christoph Liebetrau, Maren Weferling, and J Vietheer
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medicine.medical_specialty ,Ejection fraction ,Ischemic cardiomyopathy ,business.industry ,Cardiomyopathy ,Dilated cardiomyopathy ,medicine.disease ,Heart failure ,Internal medicine ,Propensity score matching ,Cardiology ,medicine ,Radiology, Nuclear Medicine and imaging ,Cardiology and Cardiovascular Medicine ,business ,Radial stress ,Cardiac imaging - Abstract
Left ventricular (LV) longitudinal, circumferential, and radial motion can be measured using feature tracking of cardiac magnetic resonance (CMR) images. The aim of our study was to detect differences in LV mechanics between patients with dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) who were matched using a propensity score-based model. Between April 2017 and October 2019, 1224 patients were included in our CMR registry, among them 141 with ICM and 77 with DCM. Propensity score matching was used to pair patients based on their indexed end-diastolic volume (EDVi), ejection fraction (EF), and septal T1 relaxation time (psmatch2 module L Feature tracking provided six parameters for global longitudinal, circumferential, and radial strain with corresponding strain rates in each group. Strain parameters were compared between matched pairs of ICM and DCM patients using paired t tests. Propensity score matching yielded 72 patients in each group (DCM mean age 58.6 ± 11.6 years, 15 females; ICM mean age 62.6 ± 13.2 years, 11 females, p = 0.084 and 0.44 respectively; LV-EF 32.2 ± 13.5% vs. 33.8 ± 12.1%, p = 0.356; EDVi 127.2 ± 30.7 ml/m2 vs. 121.1 ± 41.8 ml/m2, p = 0.251; native T1 values 1165 ± 58 ms vs. 1167 ± 70 ms, p = 0.862). There was no difference in global longitudinal strain between DCM and ICM patients (− 10.9 ± 5.5% vs. − 11.2 ± 4.7%, p = 0.72), whereas in DCM patients there was a significant reduction in global circumferential strain (− 10.0 ± 4.5% vs. − 12.2 ± 4.7%, p = 0.002) and radial strain (17.1 ± 8.51 vs. 21.2 ± 9.7%, p = 0.039). Our data suggest that ICM and DCM patients have inherently different myocardial mechanics, even if phenotypes are similar. Our data show that GCS is significantly more impaired in DCM patients. This feature may help in more thoroughly characterizing cardiomyopathy patients.
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- 2021
6. Evaluation of Patients for Percutaneous Edge-to-edge Mitral Valve Repair: Comparison of Cardiac Computed Tomography Angiography With Transesophageal Echocardiography
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Andreas Rolf, Oliver Dörr, Helge Möllmann, Holger Nef, Christian W. Hamm, Johannes Rixe, Won-Keun Kim, Ulrich Fischer-Rasokat, Claudia Walther, and Matthias Renker
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Pulmonary and Respiratory Medicine ,Male ,medicine.medical_specialty ,Percutaneous ,Computed Tomography Angiography ,medicine.medical_treatment ,Interquartile range ,Cardiac computed tomography angiography ,Internal medicine ,Mitral valve ,High spatial resolution ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Fossa ovalis ,Retrospective Studies ,Mitral valve repair ,Mitral regurgitation ,business.industry ,Mitral Valve Insufficiency ,medicine.anatomical_structure ,cardiovascular system ,Cardiology ,Mitral Valve ,Calcium ,Female ,business ,Echocardiography, Transesophageal - Abstract
PURPOSE We sought to compare parameters derived from cardiac computed tomography angiography (CCTA) with those from transesophageal echocardiography (TEE) for the evaluation of patients with severe mitral regurgitation (MR) before percutaneous edge-to-edge mitral valve repair (PE2E). TEE is the mainstay for PE2E, although it has specific limitations. CCTA enables measurements in any arbitrary plane with high spatial resolution and offers good calcium visibility. MATERIALS AND METHODS Patients who underwent TEE and CCTA before scheduled PE2E at 2 medical centers were included in this retrospective analysis. Quantitative parameters relevant for PE2E were obtained from TEE and CCTA in a blinded manner and the intrareviewer variability was assessed. RESULTS All 30 patients (15 female, 76±10 y) had secondary MR attributable to ischemic (60%) or nonischemic cardiomyopathy (40%). On comparing parameters from TEE and CCTA, left ventricular end-diastolic diameter was 60±11 versus 64±11 mm (r=0.90), intercommissural mitral annulus was 35±5 versus 35±5 mm (r=0.88), long-axis annulus was 33±5 versus 33±5 mm (r=0.74), the distance between the fossa ovalis and the leaflet coaptation was 42±5 versus 41±5 mm (r=0.81), the anterior mitral leaflet was 21±6 versus 20±7 mm (r=0.81), the posterior mitral leaflet was 13±2 versus 13±2 mm (r=0.91), and the median mitral calcification was 1 (interquartile range: 0 to 2) versus 0 (interquartile range: 0 to 1; r=0.53), respectively. Intrareviewer agreement was good and excellent for continuous and categorical variables, respectively. CONCLUSIONS Our data suggest that evaluation of the mitral valve apparatus with CCTA in patients considered for PE2E is feasible, correlates well with TEE, and offers improved calcium visibility. In selected cases, additional information from CCTA may be helpful for achieving optimal interventional results.
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- 2021
7. Prognostic impact of echocardiographic mean transvalvular gradients in patients with aortic stenosis and low flow undergoing transcatheter aortic valve implantation
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Andreas Rolf, Ulrich Fischer-Rasokat, Mirko Doss, Won-Keun Kim, Christoph Liebetrau, Maren Weferling, Matthias Renker, and Christian W. Hamm
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Aortic valve ,medicine.medical_specialty ,Hemodynamics ,030204 cardiovascular system & hematology ,Severity of Illness Index ,Transcatheter Aortic Valve Replacement ,03 medical and health sciences ,0302 clinical medicine ,Afterload ,Internal medicine ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,In patient ,030212 general & internal medicine ,Retrospective Studies ,Heart Valve Prosthesis Implantation ,Body surface area ,Ejection fraction ,business.industry ,Stroke Volume ,Aortic Valve Stenosis ,General Medicine ,Stroke volume ,Prognosis ,medicine.disease ,Stenosis ,Treatment Outcome ,medicine.anatomical_structure ,Echocardiography ,Aortic Valve ,Cardiology ,Cardiology and Cardiovascular Medicine ,business - Abstract
Background Blunted left ventricular hemodynamics reflected by a low stroke volume index (SVI) ≤35 mL/m2 body surface area (low flow [LF]) in patients with severe aortic stenosis (AS) are associated with worse outcomes even after correction of afterload by transcatheter aortic valve implantation (TAVI). These patients can have a low or high transvalvular mean pressure gradient (MPG). We investigated the impact of the pre-interventional MPG on outcomes after TAVI. Methods Patients with LF AS were classified into those with normal (EF ≥ 50%; LF/NEF) or reduced ejection fraction (EF 35 mL/m2 (normal flow; NF) served as controls. Results 597 patients with LF/NEF, 264 patients with LF/REF and 975 patients with NF were identified. Among all groups those patients with a low MPG were characterized by higher cardiovascular risk. In patients with LF/REF, functional improvement post-TAVI was less pronounced in low-MPG patients. One-year survival was significantly worse in LF AS patients with a low vs. high MPG (LF/NEF 16.5% vs. 10.5%, p = 0.022; LF/REF 25.4% vs. 8.0%, p = 0.002), whereas no differences were found in NF patients (8.7% vs. 10.0%, p = 0.550). In both LF AS groups, a low pre-procedural MPG emerged as an independent predictor of mortality. Conclusions In patients with LF AS, an MPG cut-off of 40 mmHg defines two patient populations with fundamental differences in outcomes after TAVI. Patients with LF AS and a high MPG have the same favorable prognosis as patients with NF AS.
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- 2021
8. Effects of Statins After Transcatheter Aortic Valve Implantation in Key Patient Populations
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Oliver J. Liakopoulos, Matthias Renker, Celine Bänsch, Christian W. Hamm, Maren Weferling, Ulrich Fischer-Rasokat, Yeong-Hoon Choi, Eva Herrmann, Won-Keun Kim, and Christoph Liebetrau
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Male ,medicine.medical_specialty ,Statin ,Time Factors ,medicine.drug_class ,medicine.medical_treatment ,Risk Assessment ,Severity of Illness Index ,Coronary artery disease ,Transcatheter Aortic Valve Replacement ,Valve replacement ,Risk Factors ,Internal medicine ,medicine ,Humans ,cardiovascular diseases ,Aged ,Retrospective Studies ,Pharmacology ,Aged, 80 and over ,Ejection fraction ,Proportional hazards model ,business.industry ,Mortality rate ,Hazard ratio ,nutritional and metabolic diseases ,Aortic Valve Stenosis ,Protective Factors ,medicine.disease ,Stenosis ,Treatment Outcome ,Cardiology ,lipids (amino acids, peptides, and proteins) ,Female ,Hydroxymethylglutaryl-CoA Reductase Inhibitors ,Cardiology and Cardiovascular Medicine ,business - Abstract
Statin therapy after transcatheter aortic valve replacement (TAVI) is associated with better short-term and long-term outcomes. It is of interest to identify specific patient populations that may profit from statin therapy. In this retrospective, observational analysis of 2862 patients with symptomatic aortic stenosis after successful transfemoral TAVI, survival during a three-year observation period was characterized by Kaplan-Meier analyses according to statin therapy. Hazard ratios and potential interactions for specific subgroups of patients were determined by Cox regression analyses. At hospital discharge 1761 patients were on low-intensity or moderate-intensity statins, 246 patients were on high-intensity statins, and 855 patients did not take statins. Statin therapy adherence during the first 3 months post-TAVI was 91%. Mortality rates were 18.5%, 12.9%, and 6.9% for patients with no statin, low-intensity or moderate-intensity statins, and high-intensity statins (P < 0.001). Any statin therapy proved to be effective in patients in different classes of age, risk, and manifest cardiovascular disease and was independent of background medication. Statins were of particular benefit in high-risk patients with coronary artery disease [hazard ratio (HR) = 0.57], ejection fraction
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- 2021
9. Challenges of recognizing bicuspid aortic valve in elderly patients undergoing TAVR
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Christian W. Hamm, Andreas Rolf, Mirko Doss, Won-Keun Kim, Matthias Renker, Thomas Walther, Ulrich Fischer-Rasokat, Holger Nef, Helge Möllmann, and Christoph Liebetrau
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Male ,medicine.medical_specialty ,medicine.medical_treatment ,Heart Valve Diseases ,030204 cardiovascular system & hematology ,Multimodal Imaging ,Severity of Illness Index ,Transcatheter Aortic Valve Replacement ,03 medical and health sciences ,0302 clinical medicine ,Bicuspid aortic valve ,Bicuspid Aortic Valve Disease ,Valve replacement ,Predictive Value of Tests ,Interquartile range ,Internal medicine ,Multidetector Computed Tomography ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,030212 general & internal medicine ,Cardiac imaging ,Aged ,Retrospective Studies ,Aged, 80 and over ,business.industry ,Age Factors ,Calcinosis ,Reproducibility of Results ,Aortic Valve Stenosis ,Odds ratio ,medicine.disease ,Confidence interval ,Stenosis ,Echocardiography ,Aortic Valve ,Cardiology ,Female ,Aortic valve calcification ,Cardiology and Cardiovascular Medicine ,business - Abstract
Recognition of bicuspid aortic valve (BAV) may be challenging in elderly patients with heavily calcified aortic valves undergoing transcatheter aortic valve replacement (TAVR). In this subset, the diagnostic value of pre-procedural echocardiography in clinical routine is unknown. From a total of 2583 patients undergoing TAVR in our center, we determined the rate of BAV detected by routine echocardiography as documented in the medical records. Pre-procedural multidetector computed tomography (MDCT) images were retrospectively analyzed for the presence of BAV and served as reference standard. Using MDCT criteria, BAV was found in 235 (9.1%) (age 80.1 years [interquartile range 76.4; 83.4], 44.3% female). Of these, only 27/235 (11.5%) had been identified as BAV according to echocardiography reports, whereas 6/2348 (0.3%) with TAV had been wrongly diagnosed as BAV (p
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- 2019
10. Towards the EU fusion-oriented neutron source: The preliminary engineering design of IFMIF-DONES
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Kuo Tian, F. Martin-Fuertes, Angel Ibarra, W. Krolas, A. Muñoz, M. Perez, Ulrich Fischer, D. Bernardi, Tonio Pinna, Frederik Arbeiter, Mauro Cappelli, F.S. Nitti, R. Heidinger, Gioacchino Miccichè, and Angela Garcia
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Engineering ,Work package ,business.industry ,Design activities ,Mechanical Engineering ,Sound design ,Design integration ,Fusion power ,01 natural sciences ,7. Clean energy ,010305 fluids & plasmas ,Nuclear Energy and Engineering ,Work (electrical) ,0103 physical sciences ,Systems engineering ,Neutron source ,General Materials Science ,010306 general physics ,business ,Engineering design process ,Civil and Structural Engineering - Abstract
The need of a high-intensity, 14 MeV neutron source for the qualification of materials under fusion-relevant conditions has been recognized in the European fusion programme as an essential step towards the design and licensing of DEMO and future commercial fusion power plants. This need has pushed the EU to support the development of a Li(d,nx) neutron source called IFMIF-DONES (International Fusion Materials Irradiation Facility-DEMO Oriented NEutron Source) based on and taking advantage of the results obtained in the IFMIF/EVEDA (IFMIF Engineering Validation and Engineering Design Activities) project conducted in the framework of the bilateral EU-Japan Broader Approach Agreement. The design activities and the supporting R&D work of the IFMIF-DONES facility are presently being carried out in the framework of the Work Package Early Neutron Source (WPENS) of the EUROfusion Consortium in direct collaboration with F4E Agency, with the main goal of consolidating the underlying technology and developing a sound design basis in order to be ready for IFMIF-DONES construction at the early beginning of the next decade. In this paper, some important aspects of the IFMIF-DONES Preliminary Engineering Design concerning in particular the main design integration issues in the target area are presented and briefly discussed.
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- 2019
11. 1-Year Survival After TAVR of Patients With Low-Flow, Low-Gradient and High-Gradient Aortic Valve Stenosis in Matched Study Populations
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Christian W. Hamm, Matthias Renker, Won-Keun Kim, Mirko Doss, Arnaud Van Linden, Helge Möllmann, Christoph Liebetrau, Mani Arsalan, Thomas Walther, Maren Weferling, Andreas Rolf, and Ulrich Fischer-Rasokat
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medicine.medical_specialty ,Time Factors ,medicine.medical_treatment ,030204 cardiovascular system & hematology ,Risk Assessment ,Severity of Illness Index ,Transcatheter Aortic Valve Replacement ,03 medical and health sciences ,0302 clinical medicine ,Valve replacement ,Risk Factors ,Internal medicine ,medicine ,Humans ,Registries ,030212 general & internal medicine ,Low gradient ,Survival analysis ,Retrospective Studies ,business.industry ,Hazard ratio ,Hemodynamics ,Aortic Valve Stenosis ,Recovery of Function ,medicine.disease ,Confidence interval ,Stenosis ,Treatment Outcome ,Aortic Valve ,Aortic valve stenosis ,Propensity score matching ,Cardiology ,Cardiology and Cardiovascular Medicine ,business - Abstract
Objectives This study sought to examine whether the prognosis of patients with severe aortic stenosis (AS) having high versus low transvalvular mean pressure gradients (MPGs) is intrinsically different after transcatheter aortic valve replacement (TAVR), even after strict matching of baseline parameters. Background Patients with low MPG are characterized by higher cardiovascular risk and more comorbidities than other AS patients are. Methods In this retrospective, single-center study involving 2,282 patients, 3 groups were derived according to the following criteria: 1) high-gradient AS (HG-AS) (MPG ≥40 mm Hg); 2) low-flow, low-gradient AS (LFLG-AS) (MPG Results A total of 136 patients with HG-AS or LFLG-AS were identified. Kaplan-Meier survival curves were significantly different (p = 0.039), with death occurring in 11 versus 21 patients (hazard ratio: 2.12; 95% confidence interval: 1.02 to 4.39; p = 0.044), respectively. A total of 226 patients with HG-AS or pLFLG-AS were identified and here the curves were identical (p = 0.468), with death occurring in 18 versus 21 patients (hazard ratio: 1.26; 95% confidence interval: 0.67 to 2.38; p = 0.469). Conclusions This is the first study comparing survival after TAVR of patients with high versus low MPG in matched study populations. Mortality in patients with LFLG-AS was twice that of HG-AS patients. However, it appears that patients with pLFLG-AS might benefit from TAVR to the same extent as patients with HG-AS. There must be still unmasked factors that influence mortality of patients with LFLG-AS.
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- 2019
12. Determinants of paravalvular leakage following transcatheter aortic valve replacement in patients with bicuspid and tricuspid aortic stenosis
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Matthias Renker, Won-Keun Kim, Yeong-Hoon Choi, Christian W. Hamm, Thomas Walther, Ulrich Fischer-Rasokat, Holger Nef, Helge Möllmann, and Kid Bhumimuang
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Aortic valve ,medicine.medical_specialty ,medicine.medical_treatment ,Population ,030204 cardiovascular system & hematology ,03 medical and health sciences ,0302 clinical medicine ,Bicuspid aortic valve ,Valve replacement ,Internal medicine ,Medicine ,Radiology, Nuclear Medicine and imaging ,030212 general & internal medicine ,education ,education.field_of_study ,business.industry ,General Medicine ,medicine.disease ,Stenosis ,medicine.anatomical_structure ,Aortic valve stenosis ,Cardiology ,Aortic valve calcification ,Cardiology and Cardiovascular Medicine ,business ,Calcification - Abstract
Aims Paravalvular leakage (PVL) after transcatheter aortic valve replacement (TAVR) is a common complication in patients with bicuspid aortic valve (BAV). However, predictors and mechanisms of PVL are not well understood in this subset. The aim of this study was to analyse determinants and mechanisms of PVL in BAV and tricuspid aortic valve (TAV). Methods and results Of the 2394 consecutive patients undergoing transfemoral TAVR using new-generation valves at our centre, we identified 242 cases with BAV. To adjust for baseline differences, we performed 3 : 1 propensity score matching (TAVPS n = 726). We analysed the aortic root anatomy and calcification as well as the number, circumferential distribution, and predilection sites of PVL using pre-procedural multidetector computed tomography and post-TAVR echocardiography. In the matched cohort, the incidence of PVL ≥mild (BAV 51.9% vs. TAVPS 51.7%; P = 0.955) and PVL ≥moderate (BAV 5.0% vs. TAVPS 3.7%; P = 0.393), the circumferential distribution, and independent predictors were similar between BAV and TAVPS. Both the presence of peri-annular calcium chunks or LVOT calcification were highly associated with PVL in BAV and TAVPS patients, whereas in BAV patients neither the presence of a calcium bridge nor the volume of its calcification was related to PVL. Notably, the spatial localization of these lesions did not necessarily match the circumferential leak position. Conclusion The incidence, circumferential distribution, predilection sites, and predictors of PVL were similar in matched population of BAV and TAVPS patients undergoing transfemoral TAVR using new-generation devices. These novel findings suggest a common underlying mechanism of PVL in both entities.
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- 2021
13. Mid-regional pro-atrial natriuretic peptide and copeptin as indicators of disease severity and therapy response in CTEPH
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J S Wolter, Till Keller, Christoph B. Wiedenroth, Ulrich Fischer-Rasokat, Christian W. Hamm, Christoph Liebetrau, Moritz Haas, Lillith Scherwitz, Steffen D. Kriechbaum, Stefan Guth, Felix Rudolph, Andreas Rolf, Mareike Lankeit, Eckhard Mayer, and Stavros Konstantinides
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Pulmonary and Respiratory Medicine ,Pulmonary Vascular Disease ,medicine.medical_specialty ,business.industry ,medicine.drug_class ,medicine.medical_treatment ,lcsh:R ,Area under the curve ,Central venous pressure ,Cardiac index ,lcsh:Medicine ,Original Articles ,medicine.anatomical_structure ,Copeptin ,Internal medicine ,Angioplasty ,Vascular resistance ,medicine ,Cardiology ,Natriuretic peptide ,business ,Cohort study - Abstract
Background Chronic thromboembolic pulmonary hypertension (CTEPH) leads to right heart failure. Pulmonary endarterectomy (PEA) or balloon pulmonary angioplasty (BPA) restore pulmonary haemodynamics and allow cardiac recovery. This study examined the relationship of copeptin and mid-regional pro-atrial natriuretic peptide (MR-proANP) levels to disease severity and therapy response. Methods This observational cohort study included 125 patients (55 PEA/70 BPA) who underwent treatment and completed a 6-/12-month follow-up. Biomarkers, measured at baseline, prior to every BPA and at follow-up, were compared to 1) severe disease at baseline (right atrial pressure (RAP) ≥8 mmHg and cardiac index ≤2.4 L·min−1·m−2) and 2) optimal therapy response (no persistent pulmonary hypertension combined with a normalised RAP (mean PAP ≤25 mmHg, pulmonary vascular resistance (PVR) ≤3 WU and RAP ≤6 mmHg) or a reduction in mean PAP ≥25%, PVR ≥35% and RAP ≥25%). Results Severely diseased patients had higher levels of MR-proANP (320 (246–527) pmol·L−1 versus 133 (82–215) pmol·L−1; p=0.001) and copeptin (12.7 (7.3–20.6) pmol·L−1 versus 6.8 (4.4–12.8) pmol·L−1; p=0.015) at baseline than the rest of the cohort. At baseline, MR-proANP (area under the curve (AUC) 0.91; cut-off value 227 pmol·L−1; OR 56, 95% CI 6.9–454.3) and copeptin (AUC 0.70; cut-off value 10.9 pmol·L−1; OR 1.5, 95% CI 1.2–1.9) identified severely diseased patients. After PEA/BPA, levels of MR-proANP (99 (58–145) pmol·L−1; p, The assessment of cardiac stress and impact of therapy is crucial in CTEPH. Serum levels of MR-proANP are associated with haemodynamic disease severity and therapy response, and might thus support individualised patient management. https://bit.ly/2QKwb7x
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- 2020
14. Copeptin as a novel biomarker for detecting early renal dysfunction after TAVI
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M. Renker, O Doerr, H. Baumgarten, Samuel Emil Schmidt, B Hocher, Christian W. Hamm, Won-Keun Kim, Steffen D. Kriechbaum, Holger Nef, J S Wolter, Till Keller, Christoph Liebetrau, J Reifart, and Ulrich Fischer-Rasokat
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Oncology ,medicine.medical_specialty ,Copeptin ,business.industry ,Internal medicine ,medicine ,Biomarker (medicine) ,urologic and male genital diseases ,Cardiology and Cardiovascular Medicine ,business - Abstract
Background Acute kidney injury (AKI) is one of the most prevalent (10–30%) complications after transcatheter aortic valve implantation (TAVI). Furthermore, AKI is accompanied by increased mortality, a higher incidence of dialysis and blood transfusion, and a prolonged hospital stay. Although measurement of serum creatinine is the gold standard in diagnosing AKI, changes in serum creatinine may lag behind compromised renal function. Arginine vasopressin (AVP), or antidiuretic hormone, is a nine-amino acid peptide member of the hypothalamo-neurohypophysial axis. Copeptin is the C-terminal moiety of the AVP precursor pre-proAVP that is secreted into the circulation. Recently, copeptin has been suggested to play a role in chronic kidney injury. We evaluated the value of copeptin in the prediction of AKI in patients undergoing TAVI. Methods All patients with severe aortic valve stenosis undergoing TAVI between May 2011 and May 2016 were included in our study. AKI was defined by the VARC-2 definition. Patients with no AKI and stage 1 AKI were compared with patients with stage 2 or 3 AKI. Routine laboratory parameters, including creatinine, were measured immediately after blood draw. Additionally, venous blood samples were collected on admission and after 24, 48, and 72 hours, processed immediately, and stored at −80°C until assay. The copeptin concentration in serum was measured by a sandwich immunoluminometric assay. Results Copeptin levels were available in 642 patients who were treated by TAVI in our centre from 2012–2016. AKI was detected in 113 patients (17.6%), including 61 patients with stage 1 (9.5%), 29 with stage 2 (4.5%), and 23 with stage 3 (3.6%). There were no differences among these patients in baseline measurements, but serum copeptin increased in all patients with AKI 24 h post-procedure according to the AKI stage: no AKI 34.5 (18.0–59.3 pmol/L), AKI stage 1: 68.7 (34.6–130.1 pmol/L); AKI stage 2: 96.0 (48.1–185.1 pmol/L); AKI stage 3: 154.9 (79.5–280.7 pmol/L); ANOVA p Conclusion AKI subsequent to TAVI is a common and harmful complication that occurred in almost every 5th patient (17.6%) in our cohort. AVP is secreted in response to hypotension, which commonly occurs during TAVI. In our cohort of TAVI patients, those who developed AKI after TAVI showed a rapid increase in copeptin that was earlier than that of creatinine. In light of these observations, copeptin could be a new parameter for detecting early renal dysfunction. Figure 1 Funding Acknowledgement Type of funding source: None
- Published
- 2020
15. Hybrid Experimental Rocket Stuttgart: A Low-Cost Technology Demonstrator
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Anna Petrarolo, Mario Kobald, Konstantin Tomilin, Christian Schmierer, and Ulrich Fischer
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020301 aerospace & aeronautics ,Engineering ,business.product_category ,Sounding rocket ,nitrous oxide ,business.industry ,Aerospace Engineering ,Stuttgart ,02 engineering and technology ,sounding rocket ,01 natural sciences ,world record ,010305 fluids & plasmas ,Hybrid rocket Propulsion ,0203 mechanical engineering ,Rocket ,Space and Planetary Science ,Range (aeronautics) ,Paraffin fuel ,0103 physical sciences ,Aerospace engineering ,business - Abstract
On 8 November 2016 at 1030 hrs, the Hybrid Experimental Rocket Stuttgart (HEROS) 3 was launched from the European Space and Sounding Rocket Range (ESRANGE) Space Center to an apogee altitude of 32,...
- Published
- 2018
16. Predictors and outcome of conversion to cardiac surgery during transcatheter aortic valve implantation
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Helge Möllmann, Thomas Walther, Mirko Doss, Arnaud Van Linden, Christoph Liebetrau, Christian W. Hamm, Ulrich Fischer-Rasokat, Adalbert Skwara, Won-Keun Kim, Giovanni Filardo, Mani Arsalan, M. Renker, and Benjamin D. Pollock
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Male ,Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,030204 cardiovascular system & hematology ,Transcatheter Aortic Valve Replacement ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,030212 general & internal medicine ,Intraoperative Complications ,Survival rate ,Aged ,Retrospective Studies ,Aged, 80 and over ,Ejection fraction ,business.industry ,Retrospective cohort study ,General Medicine ,Odds ratio ,Conversion to Open Surgery ,Sternotomy ,Confidence interval ,Surgery ,Cardiac surgery ,Treatment Outcome ,Female ,Tamponade ,Cardiology and Cardiovascular Medicine ,Complication ,business - Abstract
Objectives Due to increasing clinical experience with transcatheter aortic valve implantation (TAVI) procedures, sophisticated imaging and advanced device technology, TAVI complication rates are low; however, patients requiring conversion to surgery are confronted with an increased mortality risk. In this retrospective study, we evaluated the predictors for conversion and the outcomes of these patients. Methods We analysed the records of all patients undergoing TAVI in our centre from 2011 to 2016 and focused on cases that required conversion to sternotomy. We investigated reasons and risk factors for conversion as well as 30-day and 1-year outcomes. Results During the study period, 32 (2.1%) of 1775 patients undergoing TAVI required immediate conversion to sternotomy. Annular rupture (5 of 32; 16%), device embolization (9 of 32; 28%) and pericardial tamponade (15 of 32; 47%) were the most common reasons for conversion. Usage of a self-expandable valve showed to be the only predictor for conversion (odds ratio 0.38, 95% confidence interval 0.16-0.90; P = 0.03). Survival at 30 days and 1 year was 56% and 41%, respectively. Patients who survived 30 days after conversion showed higher preoperative ejection fraction, shorter duration of surgery and shorter perfusion time. Conclusions In this high-volume, single-centre experience, conversion to sternotomy during TAVI occurred in about 2%, with annular rupture, device embolization and pericardial tamponade being the most common causes. Complications requiring conversion showed to be unpredictable. However, in view of these life-threatening complications, the 30-day survival rate exceeding 50% emphasizes the importance of an experienced and well-attuned heart team providing immediate access to surgical bailout procedures.
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- 2018
17. Identification of blanket design points using an integrated multi-physics approach
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Gandolfo Alessandro Spagnuolo, Ulrich Fischer, F. Franza, Lorenzo Virgilio Boccaccini, Spagnuolo G.A., Franza F., Fischer U., and Boccaccini L.V.
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Technology ,Nuclear engineering ,DEMO reactor ,Blanket ,7. Clean energy ,01 natural sciences ,010305 fluids & plasmas ,Coupling ,0103 physical sciences ,Multi-physics approach ,General Materials Science ,Point (geometry) ,Design point ,010306 general physics ,Settore ING-IND/19 - Impianti Nucleari ,Civil and Structural Engineering ,Requirements engineering ,business.industry ,Mechanical Engineering ,Nuclear power ,Fusion power ,Finite element method ,Nuclear Energy and Engineering ,Heat flux ,Breeding blanket ,business ,ddc:600 - Abstract
The breeding blanket (BB) is one of the key components for a fusion reactor. It is expected to sustain and remove considerable heat loads due to the heat flux coming from the plasma and the nuclear power deposited by the fusion neutrons. In the design of the BB, the engineering requirements of nuclear, material and safety kind are involved. In the European DEMO project, several efforts are dedicated to the development of an integrated simulation-design tool able to perform a multi-physics analysis, allowing the characterisation of BB design points which are consistent from the neutronic, thermal-hydraulic and thermo-mechanical point of view. Furthermore, at Karlsruhe Institute of Technology, within the framework of EUROfusion activities, a new research campaign has been launched to set-up such a coupling procedure. The first step starts with the definition of the reference geometry which is converted into a more suitable format for neutronic analysis with Monte Carlo codes. In the second step, the results referred to the calculated power density are properly imported and mapped into an analysis platform based on the Finite Element Method. The procedure has been successfully tested on a dedicated model (slice) of the helium cooled pebble bed blanket.
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- 2017
18. Interventionelle Mitralklappen-Therapien
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Holger Nef, Ulrich Fischer-Rasokat, and Claudia Walther
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Gynecology ,03 medical and health sciences ,medicine.medical_specialty ,0302 clinical medicine ,High risk patients ,030202 anesthesiology ,business.industry ,medicine ,030208 emergency & critical care medicine ,General Medicine ,business - Abstract
In den letzten Jahren kam es zu einer enormen Entwicklung im Bereich der perkutanen Mitralklappentherapien. Insbesondere die katheterbasierten Mitralklappenrekonstruktionen haben sich als eine gut durchfuhrbare und bei Hochrisiko-Patienten weniger invasive Therapieoption herausgestellt. Die meiste Erfahrung existiert weltweit mit dem sogenannten MitraClip System, welches sowohl in Registern als auch in randomisierten Studien sehr gute prozedurale Ergebnisse und klinische Erfolge bei Hochrisiko-Patienten nachweisen konnte. In Zentren mit groser Erfahrung wird diese Therapie bereits als Standardtherapie bei entsprechenden Patienten eingesetzt. Die anderen neueren Therapieverfahren sind vielversprechend, stehen jedoch noch am Anfang ihrer klinischen Entwicklung und mussen in Registern und Studien weiter evaluiert werden.
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- 2017
19. Numerical Analysis of Bird Strike Resistance of Helicopter Searchlight
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Frederik Steenbergen, Sebastian Heimbs, Willy Theiler, and Ulrich Fischer
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aviation ,Engineering ,Computer simulation ,business.industry ,Airworthiness ,Bird strike ,02 engineering and technology ,Structural engineering ,021001 nanoscience & nanotechnology ,Collision ,Finite element method ,aviation.accident_type ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Windshield ,Airframe ,0210 nano-technology ,business ,Failure mode and effects analysis ,Earth-Surface Processes - Abstract
Bird strike is a major threat to aircraft structures, as a collision with a bird during flight can lead to serious structural damage. For helicopters the windshield, forward airframe structure, rotor blades and all exterior equipment parts are exposed to the risk of bird impact. Consequently, aviation authorities require that such structures need to prove bird strike resistance before they are allowed for operational use, which primarily had to be demonstrated in full-scale bird impact tests in the past. Today, as numerical simulation techniques have evolved and proven accuracy, compliance can more and more be shown by sufficiently validated numerical analyses. This study shows such an example of successful simulative demonstration of bird strike resistance of a searchlight and its pod as external equipment of a military helicopter. The finite element model was built up and validated step by step according to the building block approach from coupon level up to the full-scale structural level. The focus was on the accurate non-linear constitutive modeling of the different aluminum alloys and mechanical fasteners of the target structure. The searchlight pod as well as its internal electrical components and attachments were modelled with a high level of detail in order to allow for accurate results evaluations. A validated smoothed particle hydrodynamics (SPH) bird impactor model was used to simulate different load cases and impact positions of this fluid-structure interaction scenario with a water-like soft body projectile. Although plastic deformations and partial fracture of the outer housings of the structure were observed, no critical failure mode, detachment of critical parts or loss of structural integrity occurred. These analyses were accepted by the authorities as means of compliance and demonstrate today's progress in airworthiness certification by simulation.
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- 2017
20. Neutronics analysis for the ITER core imaging X-ray spectrometer
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Victor Udintsev, Ulrich Fischer, Raphaël Thenevin, Robin Barnsley, Arkady Serikov, Luciano Bertalot, Alejandro Suarez, and Richard O’Connor
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Neutron transport ,Materials science ,Spectrometer ,business.industry ,Mechanical Engineering ,Nuclear engineering ,Shields ,Flange ,01 natural sciences ,010305 fluids & plasmas ,Nuclear Energy and Engineering ,0103 physical sciences ,Electromagnetic shielding ,General Materials Science ,Neutron ,Radiation protection ,010306 general physics ,business ,Beam (structure) ,Civil and Structural Engineering - Abstract
This paper presents new results of the MCNP neutronics analysis for the core imaging X-ray spectrometer (CIXS) system of the ITER Equatorial Port Plug #17 (EPP#17). Substantial radiation shielding design improvements of the CIXS system have been suggested as the outcomes of this analysis. These suggested improvements allow reaching two major goals: (1) radiation protection of the CIXS Port Interspace (PI) to provide personnel access for maintenance of the vacuum extension flange; (2) reduction of the neutron and gamma loads on the detectors to reduce the need for maintenance itself. By implementing the improvements in our models such as filling void spaces around the CIXS beams with boron carbide and inserting the tungsten collimators in the narrowed beam channel, we were able to reduce the Shut-Down Dose Rate (SDDR) in the PI by 100× from 2 mSv/h in the original CIXS design to 20 microSv/h. In case of non-changed MCNP geometry, the D1S method was applied in calculations of SDDR. To allow the maintenance access to the flange, a part of shielding was removed, therefore the R2Smesh methodology was applied instead of D1S. During the maintenance access of CIXS from the PI side, a screen plate was proposed to introduce behind which a worker receives much less SDDR.
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- 2016
21. P5281Synthetic extracellular volume quantification by cardiac magnetic resonance imaging - a reliable tool in clinical practice?
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J Vietheer, Christoph Liebetrau, Ulrich Fischer-Rasokat, L Zipse, Andreas Rolf, J S Wolter, Maren Weferling, Till Keller, Steffen D. Kriechbaum, Christian W. Hamm, C Unbehaun, and S Nunn
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Clinical Practice ,medicine.diagnostic_test ,Cardiac magnetic resonance imaging ,business.industry ,Extracellular fluid ,medicine ,Cardiology and Cardiovascular Medicine ,business ,Biomedical engineering - Abstract
Background Extracellular volume (ECV) quantification by CMR imaging allows the measurement of changes in the extracellular space indicating diffuse edema and fibrosis, especially in early stages of myocardial disease. Usually venous hematocrit (Hct) is needed in order to calculate standard ECV. Recent findings suggest the alternative use of the blood pool T1-relaxation time (T1blood) instead of the venous Hct to generate “synthetic Hct ” and furthermore “synthetic ECV”, allowing a more routine and user-friendly application without the need of a current blood sample. Purpose Purpose of this study is to re-evaluate whether the connection between venous Hct and T1blood can be used to generate a synthetic ECV in a large number of volunteers and patients with various myocardial diseases from a tertiary care centre. Methods 945 volunteers and patients were divided into a derivation (n=490) and a validation group (n=455). Standard ECV was calculated using T1-relaxtion times acquisitioned in the septal myocardium and blood pool, each on pre- and post-contrast Images using a modified look-locker sequence at a 3 Tesla MR-scanner. In addition venous Hct was measured in a blood sample drawn prior to the scan. Synthetic Hct was derived through linear regression analysis between venous Hct and 1/T1blood and was then compared to venous Hct. Also we derived standard ECV and synthetic ECV and examined these using Lin's rho and Bland-Altman comparison. Results In the derivation group venous Hct and 1/T1blood showed a linear relationship (R2=0,22; p=ehz746.02521). This was used to calculate synthetic Hct and synthetic ECV. Synthetic ECV correlated well with standard ECV (Lin's rho= 0,903; p Table 1. Patient characteristics Sex female (%) 312 (33%) Age, yrs 60±15 EDVi, ml/m2 86±31 ESVi, ml/m2 43±30 LVEF, % 54±16 Hematocrit, % 43±5 Figure 1 Conclusion Despite only weak correlation of synthetic and venous Hct we found excellent correlation in synthetic and standard ECV. Therefore we could confirm the value of synthetic ECV in a large cohort of volunteers and patients, providing a feasible and non-invasive marker for extracellular myocardial alterations in everyday clinical practice.
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- 2019
22. P3710Long term follow-up in a real-world study cohort after patent foramen ovale closure
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Christian W. Hamm, O Doerr, L Schulz, T Koerschgen, Christoph Liebetrau, Ulrich Fischer-Rasokat, Till Keller, Holger Nef, and Moritz Haas
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medicine.medical_specialty ,business.industry ,Cohort ,medicine ,Patent foramen ovale ,Closure (psychology) ,Cardiology and Cardiovascular Medicine ,medicine.disease ,business ,Surgery ,Term (time) - Abstract
Background Patent foramen ovale (PFO) closure is the treatment of choice after cryptogenic stroke according recent evidence. The indication is based on results of several randomized controlled trials; however, the results of these trials may not be extrapolated to a real-world clinical setting. Therefore, the aim of the present study was to evaluate long-term outcome regarding recurrent stroke, migraine, and/or peripheral embolism in patients after PFO closure. Methods We retrospectively analyzed outcomes of consecutive patients undergoing PFO closure from 2011 to 2018 at two interventional sites with respect to periprocedural events occurring during hospitalization and long-term follow-up. Follow-up data were collected from outpatient visits or telephone interviews. Results The analysis included 214 consecutive patients (mean age 52 years; 58% male). The follow-up rate was 96% and the mean follow-up time was 38 (SD 22) months. The index vascular event leading to PFO closure was stroke (n=190; 89%), including patients with repetitive stroke (n=36), embolic myocardial infarction (n=21), and migraine (n=3). One quarter (24.6%) of the population studied had an atrial septal aneurysm (>15 mm). Procedural success was achieved in 98%. There were no procedure-related strokes or deaths. Periprocedural complications occurred in 16 patients (7%): two cases of pericardial tamponade, seven complications at the access site mainly caused by bleeding, two cases of transient atrial fibrillation, and five other complications. The Amplatz Septal Occluder™ was used in two thirds (64.5%) of the cases and the Gore Cardioform™ device in one third (28.6%). Four (2%) patients died during follow-up. None of these patients experienced a recurrent stroke. Ten (5%) other patients experienced a recurrent stroke. Patients with recurrent stroke events were older than patients without recurrent stroke (mean 62.6 [SD 8.8] years vs. mean 52.2 [SD 13.8] years; p=0.015) and had a higher rate of preexisting cerebrovascular occlusive disease (5 [50%] vs. 10 [6%]; p Conclusion In this real-world PFO closure cohort the recurrent stroke rate is low, although it is higher than reported in the recent randomized controlled trials. Recurrent strokes after PFO closure may reflect additional comorbid risk factors such as age or cerebrovascular occlusive disease that are unrelated to the potential for paradoxical embolism.
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- 2019
23. P5260Differences in myocardial mechanics between dilated cardiomyopathy and ischemic cardiomyopathy by CMR derived feature tracking strain - A propensity score-matched study
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L Zipse, Andreas Rolf, Maren Weferling, J Vietheer, Christian W. Hamm, Steffen D. Kriechbaum, Till Keller, C Unbehaun, and Ulrich Fischer-Rasokat
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medicine.medical_specialty ,Ischemic cardiomyopathy ,business.industry ,Dilated cardiomyopathy ,Strain (injury) ,medicine.disease ,Myocardial mechanics ,Internal medicine ,Propensity score matching ,medicine ,Cardiology ,Feature tracking ,Cardiology and Cardiovascular Medicine ,business - Abstract
Background Adult heart failure in industrialized nations is primarily due to dilated (DCM) and ischemic cardiomyopathy (ICM). Both diseases are characterized by different pathological pathways. While ICM is predominantly caused by local, subendocardial myocyte necrosis, DCM is characterized by a general myocyte apoptosis involving all myocardial layers. Using feature tracking, longitudinal, circumferential, and radial motion of the left ventricle (LV) can be measured, which allows the function of subendocardial, mostly longitudinal orientated, and subepicardial, mostly circumferential orientated fibers to be assessed independently. Purpose It was the aim of our study to detect differences of LV motion between DCM and ICM patients in a propensity score-matched cohort. Methods Between April 2017 and December 2018 we included 845 patients with a clinical indication for CMR in our tertiary care center registry. Out of this cohort we identified 273 patients with ICM and 126 with DCM. Propensity score matching was used to pair patients in each group based on their indexed enddiastolic volume (EDVi), ejection fraction (EF), septal T1. Feature tracking technique was used for strain analyses quantified on steady state free precession cine CMR images yielding six strain parameters. Results Propensity score matching yielded 59 patients in each group (ICM mean age 59.4±13.0 years, 11 females; DCM mean age 66.5±10.6 years, 15 females; LV-EF 32.6±11.4% vs. 33.0±14.2%, p=0.8178; EDVi 124.2±36 ml/m2 vs. 132.9±42 ml/m2, p=0.0909; native T1 values 1161±66 ms vs. 1164±59 ms, p=0.7049). There was no difference in global longitudinal strain between ICM and DCM patients (−10.9±4.4% vs. −10.6±5.8%, p=0.686), whereas global circumferential strain and radial strain were reduced in DCM patients (−12.0±4.3% vs. −10.31±4.8%, p=0.0190 and 21.1±8.9% vs. 18.0±15.5%, p=0.0386). Conclusion Our data confirm the inherently different mechanics of ICM and DCM patients. While myocardial fibres are globally affected in DCM, myocardial damage is predominantly confined to subendocardial layers in ICM despite equally reduced EF.
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- 2019
24. Integration of safety in IFMIF-DONES design
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Fernando Mota, Maria Teresa Porfiri, Ulrich Fischer, Yuefeng Qiu, Ángela Cortés, Francisco Ogando, Angel Ibarra, Tonio Pinna, Eduardo Gallego, Miguel E. García, Pedro Fernández, F. Martin-Fuertes, Elena Fernández, Gianluca D’Ovidio, Atte Helminen, Slawomir Potempski, Martin-Fuertes, F., Garcia, M. E., Fernandez, P., Cortes, A., D'Ovidio, G., Fernandez, E., Pinna, T., Porfiri, M. T., Fischer, U., Ogando, F., Mota, F., Qiu, Y., Helminen, A., Potempski, S., Gallego, E., and Ibarra, A.
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safety ,fusion ,Technology ,lcsh:Industrial safety. Industrial accident prevention ,Process (engineering) ,Computer science ,Nuclear engineering ,Regulatory requirements ,01 natural sciences ,Linear particle accelerator ,010305 fluids & plasmas ,Linear accelerator ,SDG 3 - Good Health and Well-being ,regulatory requirements ,0103 physical sciences ,Regulatory requirement ,Neutron ,lcsh:T55-55.3 ,010306 general physics ,Safety, Risk, Reliability and Quality ,Fusion ,lcsh:R5-920 ,business.industry ,High intensity ,IFMIF-DONES ,Safety ,Public Health, Environmental and Occupational Health ,linear accelerator ,Electromagnetic shielding ,Neutron source ,Radiation protection ,business ,lcsh:Medicine (General) ,Safety Research ,ddc:600 - Abstract
The IFMIF-DONES (International Fusion Material Irradiation Facility-DEMO Oriented NEutron Source) facility is being designed with the general objective of providing irradiation of representative samples of power fusion machine materials under prototypical conditions. A linear accelerator will deliver deuterons at high intensity to circulating lithium in a loop, which will produce neutrons capable of obtaining the required damage conditions. As a result of this process, radionuclides will be produced as a by-product, which is characterized by several degrees of mobility. Shielding and radiation protection measures will be required in the facility. IFMIF-DONES will be classified as a first class radioactive facility according to national regulations, with Spain being the European candidate to site the facility. Several aspects of the main safety instructions affecting the facility&rsquo, s design are explained and discussed in this paper.
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- 2019
25. Automated supervised learning pipeline for non-targeted GC-MS data analysis
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Jochen Vestner, Ulrich Fischer, and Kimmo Sirén
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Computer science ,Pipeline (computing) ,Feature extraction ,lcsh:Analytical chemistry ,01 natural sciences ,Biochemistry ,Article ,Analytical Chemistry ,Chemometrics ,03 medical and health sciences ,Exploratory data analysis ,Machine learning ,Metabolomics ,Environmental Chemistry ,Spectroscopy ,030304 developmental biology ,Feature detection (computer vision) ,0303 health sciences ,Data processing ,lcsh:QD71-142 ,business.industry ,010401 analytical chemistry ,Supervised learning ,Pattern recognition ,Classification ,0104 chemical sciences ,Tensor decomposition ,Artificial intelligence ,business ,Raw data - Abstract
Non-targeted analysis is nowadays applied in many different domains of analytical chemistry such as metabolomics, environmental and food analysis. Conventional processing strategies for GC-MS data include baseline correction, feature detection, and retention time alignment before multivariate modeling. These techniques can be prone to errors and therefore time-consuming manual corrections are generally necessary. We introduce here a novel fully automated approach to non-targeted GC-MS data processing. This new approach avoids feature extraction and retention time alignment. Supervised machine learning on decomposed tensors of segmented chromatographic raw data signal is used to rank regions in the chromatograms contributing to differentiation between sample classes. The performance of this novel data analysis approach is demonstrated on three published datasets., Graphical abstract Image 1, Highlights • Fully automated and no user input required. • Neither feature detection, nor retention time alignment is applied. • Segmented GC-MS raw data is used for machine learning. • Approach takes advantage of the sample size of experiment for classification. • Performance of the data analysis pipeline is demonstrated on three published datasets.
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- 2019
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26. The European approach to the fusion-like neutron source: The IFMIF-DONES project
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F.S. Nitti, Nicolas Chauvin, Mauro Cappelli, Frederik Arbeiter, A. Aiello, David Regidor, Angel Ibarra, R. Heidinger, D. Bernardi, F. Martin-Fuertes, S. Gordeev, S. Chel, Tonio Pinna, Ulrich Fischer, W. Krolas, A. Muñoz, N. Bazin, G. Devanz, Florian Schwab, Gioacchino Miccichè, Ibarra, A., Arbeiter, F., Bernardi, D., Krolas, W., Cappelli, M., Fischer, U., Heidinger, R., Martin-Fuertes, F., Micciche, G., Munoz, A., Nitti, F. S., Pinna, T., Aiello, A., Bazin, N., Chauvin, N., Chel, S., Devanz, G., Gordeev, S., Regidor, D., and Schwab, F.
- Subjects
Nuclear and High Energy Physics ,Engineering ,Work package ,Facilities engineering ,business.industry ,Fusion power ,Condensed Matter Physics ,facilities engineering ,fusion-like neutron source ,materials irradiation ,01 natural sciences ,7. Clean energy ,010305 fluids & plasmas ,0103 physical sciences ,Systems engineering ,Neutron source ,010306 general physics ,business ,Engineering design process ,Critical path method ,Design evolution - Abstract
The need of a neutron source for the qualification of materials to be used in future fusion power reactors have been recognized in the European (EU) fusion programme for many years. The construction and exploitation of this facility is presently considered to be in the critical path of DEMO. This issue prompted the EU to launch activities for the design and engineering of the IFMIF-DONES (International Fusion Materials Irradiation Facility-DEMO Oriented Neutron Source) facility based on and taking profit of the results obtained in the IFMIF/EVEDA (Engineering Validation and Engineering Design Activities) project, presently conducted in the framework of the EU-Japan Bilateral Agreement on the Broader Approach to Fusion. These activities and R&D work for the IFMIF-DONES Plant are presently taking place in the framework of a work package of the EUROfusion Consortium, in direct collaboration with the Fusion for Energy Organization. The main objective of these activities is to consolidate the design and the underlying technology basis in order to be ready for IFMIF-DONES construction as early as possible. The paper presents the main engineering results for a generic site obtained during the first years of design work, as indicated in the recently released IFMIF-DONES Preliminary Engineering Design Report, making emphasis on the design evolution from previous phases and on the critical issues to be further developed in the near future. The proposed European site to host the facility (Granada, Spain) is briefly introduced as well.
- Published
- 2019
27. APPLICATION OF SUPERMC3.2 TO PRELIMINARY NEUTRONICS ANALYSIS FOR EUROPEAN HCPB DEMO
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Bin Wu, Jing Song, Ulrich Fischer, Bin Li, Lijuan Hao, and G. X. Sun
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Technology ,Neutron transport ,Tokamak ,QC1-999 ,HCPB ,Nuclear engineering ,gwwg ,Blanket ,Radiation ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,law ,0103 physical sciences ,supermc ,Neutronics ,Nuclear fusion ,neutronics ,Neutron ,010306 general physics ,DEMO ,TBR ,business.industry ,Physics ,Nuclear power ,SuperMC ,hcpb demo ,Electromagnetic shielding ,Environmental science ,GWWG ,business ,ddc:600 ,tbr - Abstract
In the D-T fueled tokamak, the neutrons not only carry the approximately 80% energy released in the per fusion reaction, but also are the source of radioactivity in the fusion system. Therefore, high-fidelity neutronics simulation is required to support such reactor design and safety analysis. In the present work, taking European HCPB DEMO (Helium Cooled Pebble Bed demonstration fusion plant) developed by KIT (Karlsruhe Institute of Technology) as an example, the preliminary neutronics analysis covering the assessments of NWL (neutron wall loading), TBR (tritium breeding ratio), nuclear power generation, radiation loads on PFCs (plasma-facing components) and TFCs (toroidal field coils) has been carried out by using SuperMC in the case of both unbiased and biased simulations. The preliminary results indicate that the blanket scheme could satisfy the design requirements in terms of TBR and shielding of inboard blankets. Specially, a speed-up by ~164 times in the calculation for thick shielding region (TFC region) is achieved by using global weight windows generated via GWWG in SuperMC. In addition, compared to MCNP, SuperMC shows advantages in accurate and efficient modeling of complex system, efficient calculation and 3D interactive visualization.
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- 2021
28. Low Cost Small-satellite Access to Space using Hybrid Rocket Propulsion
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C. Schmierer, Ulrich Fischer, Mario Kobald, Stefan Schlechtriem, and Konstantin Tomilin
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Access to space ,020301 aerospace & aeronautics ,business.product_category ,Spacecraft propulsion ,Payload ,Computer science ,business.industry ,Aerospace Engineering ,02 engineering and technology ,Propulsion ,Solid fuel ,01 natural sciences ,Automotive engineering ,Manufacturing cost ,0203 mechanical engineering ,Rocket ,Small launcher ,0103 physical sciences ,Paraffin fuel ,Rocket engine ,business ,hybrid Propulsion ,010303 astronomy & astrophysics ,Gas generator - Abstract
Increased demand for smallsat launch capabilities drives on the search for low-cost launch vehicles. Hybrid rocket technology has been pushed forward in the recent years and is now ready to meet the demand of this low-cost rocket development. With intrinsic safety and reliability the development and production cost of hybrid rocket engines can be a small fraction of bi-liquid propulsion systems. At the German Aerospace Center DLR a hybrid rocket engine is developed in cooperation with the German start-up company HyImpulse Technologies GmbH in order to advance launcher technology in Germany. A concept for a mini-launcher has been designed by HyImpulse and the development of a 75 kN (SL) hybrid rocket engine is on-going with a test campaign foreseen in 2019. This engine will be the largest hybrid rocket engine ever tested in Europe. It takes advantage of the long development and research history of paraffin-based hybrid rockets at the DLR Lampoldshausen. Since 2010 paraffin-based fuels have been analyzed and improved. Additives have been found to greatly improve the mechanical properties of the paraffin solid fuel. At the same time the regression rate has been modulated to adapt the fuel for use in launcher applications. The concept of the HyImpulse mini-launcher includes eleven engines of this type, which will result in large scale serial production for the foreseen launch rate of twelve launches per year. This further reduces production costs of the hybrid rocket engine. The advantage of paraffin-based fuel lies in the simple geometry of the grain caused by the high regression rate. A cylindrical fuel grain will have a much lower manufacturing cost compared to classical wagon wheel fuel grains with HTPB. Hybrid launchers are often used within pressure fed propulsion systems, but in order to increase the payload of the launcher, this is replaced with a gas generator and turbo pump driven propulsion system for this launcher concept.
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- 2018
29. P4506Outcome of patients with heart failure and mid-range ejection fraction after transcatheter aortic valve implantation (TAVI)
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Andreas Rolf, M. Renker, Maren Weferling, Ulrich Fischer-Rasokat, Helge Moellmann, Christian W. Hamm, T Walther, A. Van Linden, Mani Arsalan, Christoph Liebetrau, Mirko Doss, and Won-Keun Kim
- Subjects
medicine.medical_specialty ,Ejection fraction ,Transcatheter aortic ,business.industry ,Heart failure ,Internal medicine ,medicine ,Cardiology ,Cardiology and Cardiovascular Medicine ,medicine.disease ,business - Published
- 2018
30. Clinical symptoms of stable ischaemic heart disease
- Author
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Ulrich Fischer-Rasokat and C. W. Hamm
- Subjects
medicine.medical_specialty ,business.industry ,Internal medicine ,Cardiology ,Medicine ,Ischaemic heart disease ,cardiovascular diseases ,business - Abstract
Ischaemic heart disease (IHD) becomes symptomatic when myocardial demand exceeds blood supply. Myocardial ischaemia leads to a wide range of symptoms, including chest pain as well as diffuse, worrisome sensations, all of which can be summarized under the term ‘chest discomfort’. Cardiac chest discomfort may be characterized according to four attributes: character, location, duration, and association with provoking or relieving factors. Typical angina pectoris, with a very high probability of significant epicardial coronary stenosis, can be diagnosed if three pre-specified criteria are met, whereas atypical angina pectoris, with only a moderate probability of IHD, and non-anginal chest pain fulfil fewer of these criteria. Angina pectoris can be quantified according to the Canadian Cardiovascular Society classification, which is based on threshold activities of angina-limited physical exertion. Some patients with IHD do not complain of chest discomfort but report symptoms such as sweating, nausea, or dyspnoea that have been demonstrated to be early indicators of IHD, denoted here as ‘angina equivalents’. Patients who do not experience any symptoms at all although myocardial ischaemia is detected are said to have ‘silent’ ischaemia. Patients with chest pain or discomfort use certain uniform hand gestures to describe the localization and character of the pain; thus, body language may be complementary to diagnostic criteria for IHD. Women are more likely to present with atypical forms of chest discomfort, and IHD is diagnosed roughly 10 years later in women than in men. Careful interpretation of patients’ descriptions of their symptoms is crucial to correctly diagnosing IHD.
- Published
- 2018
31. Overview over DEMO design integration challenges and their impact on component design concepts
- Author
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G. Federici, T. Eade, J. Keep, C. Gliss, N. Taylor, Fabio Cismondi, Th. Franke, F. Maviglia, J. Morris, Michael Loughlin, Pavel Pereslavtsev, C. Bachmann, Fabio Moro, Ulrich Fischer, Francisco Hernandez, Ronald Wenninger, Sergio Ciattaglia, and Z. Vizvary
- Subjects
Integrated design ,Tokamak ,Computer science ,business.industry ,Mechanical Engineering ,Design integration ,Fusion power ,Blanket ,01 natural sciences ,7. Clean energy ,GeneralLiterature_MISCELLANEOUS ,010305 fluids & plasmas ,law.invention ,Nuclear Energy and Engineering ,law ,Component (UML) ,0103 physical sciences ,Systems engineering ,General Materials Science ,Electricity ,Architecture ,010306 general physics ,business ,Civil and Structural Engineering - Abstract
The EU fusion roadmap defines as one of its goals the development of a Demonstration Fusion Power Reactor (DEMO) to follow ITER. This device shall be tritium self-sufficient, produce net electricity, and acts as a component test facility to demonstrate fusion power plant relevant technologies, e.g. those of the breeding blanket. This article identifies the main DEMO requirements, introduces the rationales for the selected architecture of the DEMO tokamak, and describes how the configuration of the main tokamak components has been derived. This includes (i) the DEMO shielding concept, (ii) the segmentation of the in-vessel components and their maintenance strategy, (iii) an overview of the vessel and in-vessel component technologies, and (iv) a description of the integrated design of the breeding blanket.
- Published
- 2018
- Full Text
- View/download PDF
32. Shielding performances analysis for the IFMIF test facility based on high-fidelity Monte Carlo neutronic calculations
- Author
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Keitaro Kondo, Kuo Tian, Frederik Arbeiter, Ulrich Fischer, Lei Lu, and Yuefeng Qiu
- Subjects
Neutron transport ,Materials science ,Test facility ,business.industry ,Mechanical Engineering ,Nuclear engineering ,Monte Carlo method ,computer.software_genre ,High fidelity ,Software ,Nuclear Energy and Engineering ,Electromagnetic shielding ,Computer Aided Design ,General Materials Science ,Neutron ,business ,computer ,Civil and Structural Engineering - Abstract
The IFMIF Test Cell (TC) design was developed and optimized in the EVEDA phase, and finally the reference TC design was proposed. The present study is devoted to further investigations of open issues on the reference TC design. In order to examine the neutron streaming effect caused by pipe penetrations and gaps around removable shielding plugs, a new geometry model for neutronic analyses has been prepared directly from engineering CAD data by utilizing the McCad conversion software. All removable shielding plugs are separately described in the model and a detailed description of pipes was incorporated into the model. The calculation result suggests that the streaming effect is mitigated if the pipe penetration is designed appropriately, while the gaps around the shielding plugs above the TC have large impact on the radiation dose in the access cell. The concept of the reference TC design has been basically validated from the neutronics point of view, although the streaming effect should be compensated by the shielding capability of the test cell cover plate so that occupational workers can access to the access cell during operation.
- Published
- 2015
33. Integrated approach for fusion multi-physics coupled analyses based on hybrid CAD and mesh geometries
- Author
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Lei Lu, Ulrich Fischer, and Yuefeng Qiu
- Subjects
Physics ,Coupling ,business.industry ,Mechanical Engineering ,Monte Carlo method ,CAD ,Computational science ,Software ,Data visualization ,Nuclear Energy and Engineering ,Mesh generation ,Workbench ,General Materials Science ,Polygon mesh ,business ,Civil and Structural Engineering - Abstract
Coupled multi-physics analyses on fusion reactor devices require high-fidelity neutronic models, and flexible, accurate data exchanging between various calculation codes. An integrated coupling approach has been developed to enable the conversion of CAD, mesh, or hybrid geometries for Monte Carlo (MC) codes MCNP5/6, TRIPOLI-4, and translation of nuclear heating data for CFD codes Fluent, CFX and structural mechanical software ANSYS Workbench. The coupling approach has been implemented based on SALOME platform with CAD modeling, mesh generation and data visualization capabilities. A novel meshing approach has been developed for generating suitable meshes for MC geometry descriptions. The coupling approach has been concluded to be reliable and efficient after verification calculations of several application cases.
- Published
- 2015
34. Computed Tomography for Diagnosis and Classification of Bicuspid Aortic Valve Disease in Transcatheter Aortic Valve Replacement
- Author
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Mirko Doss, Eva Guenther, Johannes Blumenstein, Matthias Renker, Helge Möllmann, Christoph Liebetrau, Oliver Husser, Arnaud Van Linden, S Loders, Andreas Rolf, Mani Arsalan, Won-Keun Kim, Martin Arnold, Stephan Achenbach, Christian W. Hamm, Ulrich Fischer-Rasokat, Thomas Walther, Susanne Möllmann, and Luise Gaede
- Subjects
medicine.medical_specialty ,Transcatheter aortic ,medicine.medical_treatment ,Population ,Heart Valve Diseases ,Disease ,030204 cardiovascular system & hematology ,Lower risk ,Transcatheter Aortic Valve Replacement ,03 medical and health sciences ,0302 clinical medicine ,Bicuspid aortic valve ,Valve replacement ,Bicuspid Aortic Valve Disease ,Predictive Value of Tests ,Internal medicine ,Germany ,Multidetector Computed Tomography ,Prevalence ,Medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,030212 general & internal medicine ,education ,Retrospective Studies ,education.field_of_study ,business.industry ,Hemodynamics ,Retrospective cohort study ,Aortic Valve Stenosis ,medicine.disease ,Predictive value of tests ,Aortic Valve ,cardiovascular system ,Cardiology ,Cardiology and Cardiovascular Medicine ,business - Abstract
The ongoing shift toward lower risk cohorts for transcatheter aortic valve replacement (TAVR) will increasingly involve patients with bicuspid aortic valve (BAV). Existing data on the prevalence and clinical outcome are inconsistent, which may be attributed to inadequate recognition or population
- Published
- 2017
35. Early changes in N-terminal pro-B-type natriuretic peptide levels after transcatheter aortic valve replacement and its impact on long-term mortality
- Author
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Christian W. Hamm, Steffen D. Kriechbaum, Jan Sebastian Wolter, Oliver Dörr, T Walther, Mani Arsalan, M.T. Huber, Helge Möllmann, Won-Keun Kim, A. Van Linden, Christoph Liebetrau, L. Gaede, Holger Nef, Johannes Blumenstein, Alexander Berkowitsch, and Ulrich Fischer-Rasokat
- Subjects
Male ,medicine.medical_specialty ,Time Factors ,Transcatheter aortic ,medicine.drug_class ,medicine.medical_treatment ,Aortic Valve Insufficiency ,030204 cardiovascular system & hematology ,Independent predictor ,Transcatheter Aortic Valve Replacement ,03 medical and health sciences ,Ventricular Dysfunction, Left ,0302 clinical medicine ,Valve replacement ,Internal medicine ,Natriuretic Peptide, Brain ,medicine ,Natriuretic peptide ,Humans ,cardiovascular diseases ,030212 general & internal medicine ,Prospective Studies ,Mortality ,Aged ,Aged, 80 and over ,Ventricular function ,business.industry ,Peptide Fragments ,Cardiology ,Biomarker (medicine) ,Long term mortality ,Female ,N terminal pro b type natriuretic peptide ,Cardiology and Cardiovascular Medicine ,business ,hormones, hormone substitutes, and hormone antagonists ,Biomarkers ,Follow-Up Studies - Abstract
Background N-terminal pro-hormone B-type natriuretic peptide (NT-proBNP) levels correlate with higher peri-procedural mortality after transcatheter aortic valve replacement (TAVR). The long-term prognostic value of NT-proBNP within the first days after TAVR, however, remains unclear. This study examined early changes in NT-proBNP prior to and within 6 days after TAVR, the diagnostic value of this biomarker regarding aortic regurgitation (AR), and its prognostic value regarding one-year mortality. Methods and results NT-proBNP concentrations were measured in 504 consecutive patients undergoing transapical (TA) or transfemoral (TF) TAVR before and directly after TAVR as well as 4 h and 1, 2, 3, and 6 days after TAVR. The follow-up period was 1 year. NT-proBNP was elevated in all patients at baseline (median 2141 ng/L [IQR 1021–5319 ng/L]). NT-proBNP changes in the first 6 days after TAVR showed significant differences depending on the approach, with a greater and more prolonged rise evident in TA-TAVR patients. NT-proBNP was an independent predictor of mortality in TA patients with AR, with an AUC of 0.794 (95% CI 0.663–0.925; P = 0.003) when measured on day 3 after TAVR. For TF patients with AR and reduced left ventricular systolic function, the AUC for prediction of mortality was 0.897 (95% CI 0.778–1.0; P = 0.004) on day 2. Conclusions The prognostic information of early post-procedural NT-proBNP concentrations is superior to pre-procedural values regarding all-cause mortality within 1 year. Post-procedural NT-proBNP must be interpreted in relation to the TAVR approach. NT-proBNP predicts mortality in TF-TAVR patients with AR and reduced left ventricular function.
- Published
- 2017
36. 3941Worse outcome of patients with normal ejection fraction but low-gradient aortic valve stenosis after transcatheter aortic valve implantation (TAVI)
- Author
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Helge Moellmann, A. Van Linden, Christian W. Hamm, Won-Keun Kim, Ulrich Fischer-Rasokat, T Walther, Alexander Berkowitsch, Mani Arsalan, Christoph Liebetrau, and M. Renker
- Subjects
medicine.medical_specialty ,Ejection fraction ,Transcatheter aortic ,business.industry ,Internal medicine ,Aortic valve stenosis ,Cardiology ,Medicine ,Low gradient ,Cardiology and Cardiovascular Medicine ,business ,medicine.disease - Published
- 2017
37. P1638Impact of left ventricular and aortic valve characteristics on one-year mortality of patients with low-flow low-gradient aortic valve stenosis after transcatheter aortic valve implantation (TAVI)
- Author
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Helge Moellmann, Andreas Rolf, Christoph Liebetrau, Christian W. Hamm, M. Renker, Ulrich Fischer-Rasokat, T Walther, Mani Arsalan, Won-Keun Kim, and A. Van Linden
- Subjects
Aortic valve ,medicine.medical_specialty ,Transcatheter aortic ,business.industry ,medicine.disease ,One year mortality ,medicine.anatomical_structure ,Aortic valve stenosis ,Internal medicine ,medicine ,Cardiology ,Ventricular pressure ,Low gradient ,Cardiology and Cardiovascular Medicine ,business - Published
- 2017
38. P1492The results of V-A-ECMO therapy in patients after out-of-hospital-cardiopulmonary resuscitation in terms of a rescue-approach - a single-center experience
- Author
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Christoph Liebetrau, J S Wolter, J. Barmwarter, Helge Moellmann, Christian Troidl, Ulrich Fischer-Rasokat, Steffen D. Kriechbaum, Claudia Walther, Andreas Rolf, Won-Keun Kim, Christian W. Hamm, and Moritz Haas
- Subjects
Out of hospital ,medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Emergency medicine ,medicine ,In patient ,Cardiopulmonary resuscitation ,Medical emergency ,Cardiology and Cardiovascular Medicine ,medicine.disease ,Single Center ,business - Published
- 2017
39. P6062Predicting outcome with normal-range high-sensitivity troponin i and heart-type fatty acid-binding protein in stable patients with suspected coronary artery disease
- Author
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Andreas Rolf, Helge Moellmann, J S Wolter, Christian Troidl, Till Keller, Steffen D. Kriechbaum, L. Gaede, Karl J. Lackner, Christian W. Hamm, Alexander Berkowitsch, Ulrich Fischer-Rasokat, N. Osman, Holger Nef, and Christoph Liebetrau
- Subjects
Coronary artery disease ,medicine.medical_specialty ,business.industry ,Internal medicine ,Heart-type fatty acid binding protein ,High sensitivity troponin ,medicine ,Cardiology ,Cardiology and Cardiovascular Medicine ,business ,medicine.disease ,Normal range - Published
- 2017
40. Sounding Rocket 'HEROS' - A Low-Cost Hybrid Rocket Technology Demonstrator
- Author
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Konstantin Tomilin, Christian Schmierer, Jonas Breitinger, Paula Kysela, Ulrich Fischer, Anna Petrarolo, Benjamin Hochheimer, Jonas Gauger, Andreas Pahler, Mario Kobald, and Ferdinand Hertel
- Subjects
020301 aerospace & aeronautics ,Engineering ,business.product_category ,Sounding rocket ,Spacecraft propulsion ,nitrous oxide ,business.industry ,Liquid-propellant rocket ,Rocket engine test facility ,02 engineering and technology ,sounding rocket ,01 natural sciences ,Space launch ,Multistage rocket ,world record ,010305 fluids & plasmas ,Hybrid rocket Propulsion ,0203 mechanical engineering ,Rocket ,0103 physical sciences ,Paraffin fuel ,Aerospace engineering ,business ,Pendulum rocket fallacy ,HyEnD - Abstract
The inherent safety of hybrid rocket propulsion offers some unique advantages com- pared to solid and liquid propellant rocket engines. This makes it especially attractive for space tourism, Micro-launcher and hands-on experiments in the education of students. On November 8th, 2016 at 10:30 a.m. the hybrid sounding rocket HEROS 3 was launched from the ESRANGE Space Center to an apogee altitude of 32,300m (106,000 ft). This set a new altitude record for European student and amateur rocketry and a world altitude record for hybrid rockets built by students. The 7.5m long rocket was using Nitrous Oxide (N2O) and a Paraffin-based fuel to produce 10,000N of thrust. The dry mass of the rocket was only 75 kg thanks to a carbon fibre structure for the most part. The rocket performed the record breaking flight at perfect weather and visibility conditions, reaching a maximum airspeed of 720 m/s and Mach 2.3. The rocket performed a soft landing with two parachutes and can be reused. Flight data and engine performance data are published and analyzed. The flight data shows excellent stability of the rocket. Engine performance data proves very high efficiency and stable combustion as in the ground tests. The subsystem design and verification before the launch is reported. Engine and flight trajectory simulations show very good agreements with the flight data. Furthermore, the overall project, the rocket design, the subsystems as well as the launch campaign are presented here in detail.
- Published
- 2017
41. Identification of Periprocedural Myocardial Infarction Using a High-Sensitivity Troponin I Assay in Patients Who Underwent Transcatheter Aortic Valve Implantation
- Author
-
Holger Nef, Thomas Walther, Sandra Schillinger, Christian W. Hamm, Ulrich Fischer-Rasokat, Christian Troidl, Alexander Meyer, Won K. Kim, Johannes Blumenstein, Luise Gaede, Mani Arsalan, Jan Sebastian Wolter, Oliver Dörr, Helge Möllmann, and Christoph Liebetrau
- Subjects
Male ,medicine.medical_specialty ,Myocardial Infarction ,030204 cardiovascular system & hematology ,Diagnosis, Differential ,Transcatheter Aortic Valve Replacement ,03 medical and health sciences ,0302 clinical medicine ,Postoperative Complications ,Troponin T ,Internal medicine ,Germany ,Troponin I ,medicine ,Humans ,030212 general & internal medicine ,Myocardial infarction ,Retrospective Studies ,Aged, 80 and over ,business.industry ,Incidence ,Retrospective cohort study ,Aortic Valve Stenosis ,medicine.disease ,Survival Rate ,Cohort ,Preoperative Period ,cardiovascular system ,Cardiology ,Myocardial infarction complications ,Biomarker (medicine) ,Female ,Myocardial infarction diagnosis ,Cardiology and Cardiovascular Medicine ,Complication ,business ,Biomarkers ,Follow-Up Studies - Abstract
Periprocedural myocardial infarction (MI), a rare complication after transcatheter aortic valve implantation (TAVI), is associated with worse outcome. According to the Valve Academic Research Consortium (VARC-2), MI is defined by an increase in cardiac troponin (cTn) and creatine kinase MB (CK-MB) levels; however, many patients show periprocedurally elevated cTn without clinical evidence of MI. The aims of this study were to establish reference values of cardiac troponin I measured with a high-sensitivity assay (hs-cTnI) and to assess the periprocedural diagnostic value of this biomarker in patients who underwent TAVI. Hs-cTnI and CK-MB levels were assessed before and up to 3 days after transfemoral (TF) or transapical (TA) TAVI in 515 patients. A high proportion (61.2%) of patients had elevated hs-cTnI at baseline. According to VARC-2 criteria, almost all TA-patients (99.5%) showed an MI based on hs-cTnI compared with 4.2% based on CK-MB. In TF-patients, 81.1% had an MI based on hs-cTnI compared with 9.0% based on CK-MB. Only 10 patients (2%), however, had a type 1 MI. The ninety-ninth percentile for hs-cTnI was 285 ng/L in the TAVI cohort. After applying a TAVI-specific cutoff the frequency of MI was lower and more realistic (TF: 5% vs 81.1%; p 0.001; TA: 22.2% vs 99.5%; p 0.001). In conclusion, the VARC-2 definition leads to an overestimation of periprocedural MI. Our new TAVI-specific reference values yield a more realistic estimation of the myocardial ischemic risk. hs-cTnI, however, does not seem to be the biomarker of choice for MI detection in this setting.
- Published
- 2017
42. Nuclear data for fusion technology – the European approach
- Author
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Andrej Trkov, I. Kodeli, Dieter Leichtle, H. Leeb, L.W. Packer, Axel Klix, Vlad Avrigeanu, P. Pereslavtsev, Arjan J. Koning, Patrick Sauvan, Ulrich Fischer, Dimitri Rochman, Marilena Avrigeanu, Oscar Cabellos, Natalia Dzysiuk, Alexander Konobeev, and Elena Nunnenmann
- Subjects
Engineering ,Technology ,010308 nuclear & particles physics ,business.industry ,Nuclear engineering ,Physics ,QC1-999 ,Nuclear data ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Benchmarking ,Fusion power ,01 natural sciences ,0103 physical sciences ,Systems engineering ,Neutron source ,010306 general physics ,business ,ddc:600 - Abstract
The European approach for the development of nuclear data for fusion technology applications is presented. Related R&D activities are conducted by the Consortium on Nuclear Data Development and Analysis for Fusion to satisfy the nuclear data needs of the major projects including ITER, the Early Neutron Source (ENS) and DEMO. Recent achievements are presented in the area of nuclear data evaluations, benchmarking and validation, nuclear model improvements, and uncertainty assessments.
- Published
- 2017
43. Benchmarking and validation activities within JEFF project
- Author
-
I. Hill, J.-Ch. Sublet, S. C. van der Marck, M. Pecchia, F. Michel-Sendis, Do Heon Kim, I. Kodeli, L. Fiorito, Raphaelle Ichou, A. Stankovskiy, Dimitri Rochman, F. Álvarez-Velarde, Elena Nunnenmann, Y. Peneliau, Ulrich Fischer, Oscar Cabellos, M. Fleming, Pierre Leconte, Axel Klix, C.J. Diez, J. Dyrda, Wim Haeck, A. J. M. Plompen, Pablo Romojaro, P. Tamagno, Massimo Angelone, and Angelone, M.
- Subjects
Engineering ,010308 nuclear & particles physics ,Process (engineering) ,business.industry ,Physics ,QC1-999 ,Nuclear data ,Context (language use) ,Benchmarking ,01 natural sciences ,Data science ,010305 fluids & plasmas ,Variety (cybernetics) ,Engineering management ,0103 physical sciences ,Data bank ,business - Abstract
The challenge for any nuclear data evaluation project is to periodically release a revised, fully consistent and complete library, with all needed data and covariances, and ensure that it is robust and reliable for a variety of applications. Within an evaluation effort, benchmarking activities play an important role in validating proposed libraries. The Joint Evaluated Fission and Fusion (JEFF) Project aims to provide such a nuclear data library, and thus, requires a coherent and efficient benchmarking process. The aim of this paper is to present the activities carried out by the new JEFF Benchmarking and Validation Working Group, and to describe the role of the NEA Data Bank in this context. The paper will also review the status of preliminary benchmarking for the next JEFF-3.3 candidate cross-section files. © The Authors, published by EDP Sciences, 2017.
- Published
- 2017
44. Session 46. BMBF-Zwanzig20 joint project: Fast Actuator and Sensor Technologies (FAST) care
- Author
-
Andreas Müller, Jens-Uwe Just, Christian Reinboth, and Ulrich Fischer-Hirchert
- Subjects
Engineering ,business.industry ,Biomedical Engineering ,Session (computer science) ,business ,Joint (audio engineering) ,Actuator ,Simulation - Published
- 2017
45. Neutronic analyses of the HCPB DEMO reactor using a consistent integral approach
- Author
-
Pavel Pereslavtsev, Oliver Bitz, Lei Lu, and Ulrich Fischer
- Subjects
Neutron transport ,Computer science ,business.industry ,Mechanical Engineering ,Nuclear engineering ,Monte Carlo method ,Full scale ,Nuclear power ,Blanket ,Nuclear Energy and Engineering ,Shield ,Electromagnetic shielding ,General Materials Science ,business ,Civil and Structural Engineering - Abstract
This work is devoted to nuclear design analyses of the new HCPB-type DEMO reactor developed in the frame of the EFDA PPPT program. The neutronic simulations were carried out with the MCNP5 code using a full scale 3D torus sector model of the DEMO reactor. The model was generated with the McCad conversion tool from available CAD models using a consistent integral approach. The neutronic analyses addressed the tritium breeding performance, the nuclear power generation and the shielding capabilities of the reactor. Although tritium self-sufficiency was shown, the tritium breeding performance of the current design calls for further design improvements to arrive at a higher uncertainty margin. The shielding performance of the reactor is close to the limit. Sufficient shielding can be easily provided by a slight increase of the inboard shield thickness.
- Published
- 2014
46. A generic data translation scheme for the coupling of high-fidelity fusion neutronics and CFD calculations
- Author
-
Pavel Pereslavtsev, Peng Lu, Ulrich Fischer, Yuefeng Qiu, and S. Kecskes
- Subjects
Neutron transport ,Computer science ,business.industry ,Mechanical Engineering ,Monte Carlo method ,Computational fluid dynamics ,Blanket ,Computational science ,Data mapping ,Thermal hydraulics ,Nuclear Energy and Engineering ,Kernel (image processing) ,General Materials Science ,Polygon mesh ,business ,Civil and Structural Engineering - Abstract
The design of fusion device components is achieved through iterative coupled neutronics and thermal hydraulics analyses. A translation scheme has been developed for transferring the nuclear heating data from Monte Carlo (MC) neutronic calculations to CFD simulations. It contains a generic data translation kernel which supports the high-fidelity data mapping of MC meshes on CFD meshes, and provides interfaces for processing the nuclear response data on the meshes for CFD codes. This translation scheme has been implemented in the open-source pre- and post-processing platform SALOME to extend its capabilities on data manipulations and visualizations. For verification purposes, a blanket test case based on the Helium Cooled Pebble Bed Test Blanket Module was investigated. The processing of the heating distribution data was validated through a so-called Inversion Check comparing the inverted heating field with the original MC tally distribution. The results of the verification have been discussed in detail, and the reliability of the data translation scheme is concluded.
- Published
- 2014
47. Neutronic analysis for the IFMIF EVEDA reference test cell and test facility
- Author
-
Viktoria Weber, Keitaro Kondo, Dennis Große, Axel Klix, Volker Heinzel, Arkady Serikov, Ulrich Fischer, Martin Mittwollen, Kuo Tian, Lei Lu, and Frederik Arbeiter
- Subjects
Neutron transport ,Materials science ,Test facility ,business.industry ,Mechanical Engineering ,Nuclear engineering ,Isotopes of lithium ,Monte Carlo method ,chemistry.chemical_element ,Software ,Nuclear Energy and Engineering ,chemistry ,Electromagnetic shielding ,General Materials Science ,Neutron ,Lithium ,business ,Civil and Structural Engineering - Abstract
The IFMIF test cell (TC) design has been further developed and optimized in the EVEDA phase, and finally the reference TC design has been proposed. In order to carry out the detailed neutronic analysis for the reference TC design, a very detailed geometrical model for Monte Carlo neutronic calculations has been prepared directly from engineering CAD data by utilizing the McCad conversion software developed at KIT. The geometrical model includes the detailed descriptions of the lithium target system proposed by Japan, all test modules based on the EVEDA phase design, and the 3-dimesional arrangement of the biological shielding. The Monte Carlo code McDeLicious, which is an enhancement to MCNP5, has been utilized in order to adequately simulate the neutron and photon productions from the 6,7Li(d,xn) reactions in the lithium target. The present analysis is focusing on the nuclear heating distribution inside the biological shielding, the nuclear property of the TC liner, and the biological dose distribution around TC during operation. Some countermeasures for reducing the He production in the liner are discussed.
- Published
- 2014
48. The Activities of the European Consortium on Nuclear Data Development and Analysis for Fusion
- Author
-
E. Dupont, J. Izquierdo, H. Leeb, Patrick Sauvan, Dieter Leichtle, J. C. Sublet, Marilena Avrigeanu, Vlad Avrigeanu, Oscar Cabellos, Ulrich Fischer, A. Yu. Konobeyev, I. Kodeli, Dimitri Rochman, Pavel Pereslavtsev, Andrej Trkov, and Arjan J. Koning
- Subjects
Nuclear physics ,Nuclear and High Energy Physics ,Engineering ,Software ,business.industry ,Data file ,Iter tokamak ,Nuclear data ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,business - Abstract
This paper presents an overview of the activities of the European Consortium on Nuclear Data Development and Analysis for Fusion. The Consortium combines available European expertise to provide services for the generation, maintenance, and validation of nuclear data evaluations and data files relevant for ITER, IFMIF and DEMO, as well as codes and software tools required for related nuclear calculations.
- Published
- 2014
49. Quality Assurance of the Cross-sections Measured on p+Li/C Source
- Author
-
Eva Simeckova, Stanislav Simakov, Milan Štefánik, Ulrich Fischer, Pavel Bem, Mitja Majerle, and Jan Novák
- Subjects
Nuclear physics ,Physics ,Nuclear and High Energy Physics ,business.industry ,Continuum (design consultancy) ,Extraction (chemistry) ,Nuclear data ,Neutron ,Irradiation ,business ,Neutron irradiation ,Quality assurance ,Spectral line - Abstract
Irradiation of material with quasi-monoenergetic neutrons with energies up to 35 MeV is routinely used for cross-section measurement. Neutron irradiation, gamma measurement, and cross-section extraction are three steps in obtaining the final cross-section, each of them contributing to the final uncertainty. The nature of the spectra, which consists of the monoenergetic peak and the continuum at lower energies, makes the extraction of the cross-sections a non-trivial problem and different methods of extraction are used. In this paper, we identify the main sources of uncertainties, discuss possible improvements, and address the differences between some commonly used methods of cross-section extraction.
- Published
- 2014
50. The McCad Code for the Automatic Generation of MCNP 3-D Models: Applications in Fusion Neutronics
- Author
-
Ulrich Fischer, S. Podda, R. Villari, Fabio Moro, Pavel Pereslavtsev, Lei Lu, Moro, F., and Villari, R.
- Subjects
Nuclear and High Energy Physics ,neutronics ,JET ,DEMO ,Analysis ,design ,business.industry ,Computer science ,Monte Carlo method ,Analysi ,CAD ,Condensed Matter Physics ,computer.software_genre ,Computational science ,Visualization ,Software portability ,Boundary representation ,Software ,Computer Aided Design ,business ,computer ,Graphical user interface - Abstract
The Monte Carlo (MC) code MCNP is the reference tool in fusion neutronics, allowing the description and analysis of full and detailed 3-D geometry of a tokamak machine. The geometrical models of the components used are typically available through computer aided design (CAD) files: the main benefits of this system are related to its portability and compatibility with several tools commonly used in engineering analyses. However, at the present stage, the information contained in CAD files cannot be directly provided to MC as inputs, because of the different representation scheme used. This issue leads to the necessity to develop interfaces that can translate them into the correct MC geometrical description. McCad is a software developed by the Karlsruhe Institute of Technology, dedicated to the fully automated generation of the MCNP geometrical models from CAD files (step, iges, and brep formats): it is provided with a graphical user interface allowing the visualization of the geometries and tools for data exchange and modeling. This paper summarizes the results of some benchmark tests performed on JET components and a DEMO reactor aimed at the assessment of the suitability of McCad for fusion neutronic applications. The reliability of the conversion algorithm has been evaluated comparing the results of stochastic MCNP volume calculations carried out using the generated models, and the corresponding volumes provided by the CAD kernel of the interface program. Moreover, the consistency of a converted DEMO MCNP model has been verified through particle transport calculations for the estimation of the neutron wall loading poloidal distribution. Several aspects related to the use of the code have been evaluated such as its portability, performances, and impact of the geometric approximation introduced on the neutronic analyses. Furthermore, a useful feedback for the optimization and enhancement of the McCad interface has been provided. ᄅ 2014 IEEE.
- Published
- 2014
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