16 research outputs found

    Power-to-Syngas: A Parareal Optimal Control Approach

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    A chemical plant layout for the production of syngas from renewable power, H2O and biogas, is presented to ensure a steady productivity of syngas with a constant H2-to-CO ratio under time-dependent electricity provision. An electrolyzer supplies H2 to the reverse water-gas shift reactor. The system compensates for a drop in electricity supply by gradually operating a tri-reforming reactor, fed with pure O2 directly from the electrolyzer or from an intermediate generic buffering device. After the introduction of modeling assumptions and governing equations, suitable reactor parameters are identified. Finally, two optimal control problems are investigated, where computationally expensive model evaluations are lifted viaparareal and necessary objective derivatives are calculated via the continuous adjoint method. For the first time, modeling, simulation, and optimal control are applied to a combination of the reverse water-gas shift and tri-reforming reactor, exploring a promising pathway in the conversion of renewable power into chemicals

    A simple coronary CT angiography-based jeopardy score for the identification of extensive coronary artery disease: Validation against invasive coronary angiography

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    PURPOSE The invasive British Cardiovascular Intervention Society Jeopardy Score (iBCIS-JS) is a simple angiographic scoring system, enabling quantification of the extent of jeopardized myocardium related to clinically significant coronary artery disease (CAD). The purpose of this study was to develop and validate the coronary CT angiography-based BCIS-JS (CT-BCIS-JS) against the iBCIS-JS in patients with suspected or stable CAD. MATERIALS AND METHODS Patients who underwent coronary CT angiography followed by invasive coronary angiography, within 90 days were retrospectively included. CT-BCIS-JS and iBCIS-JS were calculated, with a score ≥ 6 indicating extensive CAD. Correlation between the CT-BCIS-JS and iBCIS-JS was searched for using Spearman's coefficient, and agreement with weighted Kappa (κ) analyses. RESULTS A total of 122 patients were included. There were 102 men and 20 women with a median age of 62 years (Q1, Q3: 54, 68; age range: 19-83 years). No differences in median CT-BCIS-JS (4; Q1, Q3: 0, 8) and median iBCIS-JS (4; Q1, Q3: 0, 8) were found (P = 0.18). Extensive CAD was identified in 53 (43.4%) and 52 (42.6%) patients using CT-BCIS-JS and iBCIS-JS, respectively (P = 0.88). CT-based and iBCIS-JS showed excellent correlation (r = 0.98; P < 0.001) and almost perfect agreement (κ = 0.93; 95% confidence interval: 0.90-0.97). Agreement for identification of an iBCIS-JS ≥ 6 was almost perfect (κ = 0.94; 95 % confidence interval: 0.87-0.99). CONCLUSION The CT-BCIS-JS represents a feasible, and accurate method for quantification of CAD, with capabilities not different from those of iBCIS-JS. It enables simple, non-invasive identification of patients with anatomically extensive CAD

    Duration of adenosine-induced myocardial hyperemia - Insights from quantitative 13N-ammonia positron emission tomography myocardial perfusion imaging

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    AIMS To assess the impact of adenosine on quantitative myocardial blood flow (MBF) in a rapid stress-rest protocol compared to a rest-stress protocol using 13N-ammonia positron emission tomography (PET) myocardial perfusion imaging (MPI) and to gain insights into the time dependency of such effects. METHODS AND RESULTS Quantitative MBF at rest (rMBF), during adenosine-induced stress (sMBF) and myocardial flow reserve (MFR) were obtained from 331 retrospectively identified patients who underwent 13N-ammonia PET-MPI for suspected chronic coronary syndrome and who all exhibited no perfusion defects. Of these, 146 (44.1%) underwent a rapid stress-rest protocol with a time interval (Δtstress-rest) of 20 ± 4 minutes between adenosine infusion offset and rest-imaging, as per clinical routine. The remaining 185 (55.9%) patients underwent a rest-stress protocol and served as the reference. Groups did not differ regarding demographics, risk factors, medication, left ventricular function, and calcium scores. rMBF was significantly higher in the stress-rest vs. the rest-stress group (0.80 [IQR 0.66-1.00] vs. 0.70 [0.58-0.83] ml·min-1·g-1, p < 0.001) and, as sMBF was identical between groups (2.52 [2.20-2.96] vs. 2.50 [1.96-3.11], p = 0.347), MFR was significantly lower in the stress-rest group (3.07 [2.43-3.88] vs. 3.50 [2.63-4.10], p < 0.001). There was a weak correlation between Δtstress-rest and rMBF (r = -0.259, p = 0.002) and between Δtstress-rest and MFR (r = 0.163, p = 0.049), and the proportion of patients with abnormally high rMBF was significantly decreasing with increasing Δtstress-rest. CONCLUSIONS Intravenously applied adenosine induces a long-lasting hyperemic effect on the myocardium. Consequently, rapid stress-rest protocols could lead to an overestimation of rMBF and an underestimation of MFR

    Impact of sex and gender on post-COVID-19 syndrome, Switzerland, 2020

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    Background: Women are overrepresented among individuals with post-acute sequelae of SARS-CoV-2 infection (PASC). Biological (sex) as well as sociocultural (gender) differences between women and men might account for this imbalance, yet their impact on PASC is unknown. Aim: We assessed the impact of sex and gender on PASC in a Swiss population. Method: Our multicentre prospective cohort study included 2,856 (46% women, mean age 44.2 ± 16.8 years) outpatients and hospitalised patients with PCR-confirmed SARS-CoV-2 infection.ResultsAmong those who remained outpatients during their first infection, women reported persisting symptoms more often than men (40.5% vs 25.5% of men; p < 0.001). This sex difference was absent in hospitalised patients. In a crude analysis, both female biological sex (RR = 1.59; 95% CI: 1.41-1.79; p < 0.001) and a score summarising gendered sociocultural variables (RR = 1.05; 95% CI: 1.03-1.07; p < 0.001) were significantly associated with PASC. Following multivariable adjustment, biological female sex (RR = 0.96; 95% CI: 0.74-1.25; p = 0.763) was outperformed by feminine gender-related factors such as a higher stress level (RR = 1.04; 95% CI: 1.01-1.06; p = 0.003), lower education (RR = 1.16; 95% CI: 1.03-1.30; p = 0.011), being female and living alone (RR = 1.91; 95% CI: 1.29-2.83; p = 0.001) or being male and earning the highest income in the household (RR = 0.76; 95% CI: 0.60-0.97; p = 0.030). Conclusion: Specific sociocultural parameters that differ in prevalence between women and men, or imply a unique risk for women, are predictors of PASC and may explain, at least in part, the higher incidence of PASC in women. Once patients are hospitalised during acute infection, sex differences in PASC are no longer evident

    Standard Operating Procedures (SOP) für Ultraschall-gesteuerte Regionalanästhesie : Handbuch der Ultraschall gesteuerten Regionalanästhesie zur intra- und postoperativen Schmerztherapie und deren Implementierung im Klinikbetrieb

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    Diese Arbeit gliedert in sich zwei Teile. Den ersten Teil bilden die SOP für Ultraschall gesteuerte Regionalanästhesie. Im zweiten Teil erfolgt eine Validierung der erstellten SOP. Der erste Teil bildet das Kernstück dieser Arbeit - die eigentlichen SOP für Ultraschall gesteuerte Regionalanästhesie. Nach einer Einführung in die wichtigsten Elemente der Ultraschallphysik, werden die wichtigsten Aspekte besprochen, wie man vom Ultraschallgerät zu einem guten Ultraschallbild kommt. Anschliessend werden die einzelnen Blockaden dargestellt. Die Gliederung wird dabei immer beibehalten: Synopsis, Übersicht, Anatomie, Sonoanatomie, Punktion und klinische Perlen. Dabei werden folgende Ultraschall gesteuerte Blockaden durchleuchtet: - Blockaden der oberen Extremität (interskalenär, supraclaviculär, infraclaviculär, axillär, zervikal) - Blockaden der unteren Extremität (femoral, Nervus obturatorius, Nervus cutaneus femoris lateralis, Nervus saphenus, proximaler posteriorer Nervus ischiadicus, proximaler anteriorer Nervus ischiadicus, popliteal) - Blockaden am Stamm (thorakal paravertebral, TAP, Nervi ilioinguinalis und iliohypogastricus) Im zweiten Teil wird eine Validierung der SOP durchgeführt. Diese erfolgt direkt durch Befragung von fünf unserer Assistenzärzte sowie von zwei Rotationsoberärzten, welche für ein Jahr vom Universitätspital Basel ins Bruderholzspital kommen, um sich unter anderem im Gebiet der Regionalanästhesie zu vertiefen. Eine indirekte Validierung erfolgte durch Befragung von fünf Anästhesieschwestern und -pflegern, welche in unserem Spital die tägliche Pain Visite durchführen und somit auch unsere Pain Nurses sind. Die direkte Validierung ergab, dass das Skript für alle Befragten als Grundlage zur Vorbereitung auf Blockadetechniken ist. Die SOP werden rege benutzt, vor allem am Tag vor der Blockade und am Tag der Durchführung. Alle der Mitarbeiter schätzen dieses kompakte Werk, in dem die aktuelle Literatur und Bücher bereits eingebunden sind. Die indirekte Validierung soll die Anwendung und Umsetzung der SOP widerspiegeln. Alle Befragten äusserten sich sehr positiv. So konnte eine starke Steigerung des Patientenkomforts und der Erfolgsrate erzielt werden. Auch der Verbrauch an Lokalanästhetika hat stark abgenommen. Bei der Pain Visite konnten wir eine massive Zunahme an gut liegenden Katheter verzeichnen mit stark reduziertem Opiatverbrauch auf Station. Konklusiv bilden die SOP eine wertvolle Stütze in der Ausbildung von Assistenzärzten. Dadurch konnten wir ein gutes Niveau in Regionalanästhesie erreichen im Sinne einer Qualitätssteigerung.vorgelegt von: Michael Dominik SagerMedizinische Universität Wien, Masterarb., 201

    The Role of Trust in the Participatory Establishment of Protected Areas—Lessons Learnt from a Failed National Park Project in Switzerland

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    This article explores the reasons for the local rejection of a proposed national park in Switzerland. Using a mixed-methods approach and resorting to qualitative and quantitative data, we follow the thread of trust issues in the participatory planning process of a protected area. Different rationales and discourses, both project-specific but also more general, influenced the opinions of local stakeholders. Connecting these different opinions was the issue of (dis)trust, which weaves in and out of prominent lines of argumentation and informs individual sentiments. The application of a multidimensional trust framework helps to understand the influence of different types of trust on protected area negotiations. We discuss how a focus on rational trust building can help to sharpen the diverse goals of contemporary protected areas with integrated conservation and economic development schemes, as well as enable the emergence of other types of trust to facilitate conservation debates

    The Role of Trust in the Participatory Establishment of Protected Areas - Lessons Learnt from a Failed National Park Project in Switzerland

    No full text
    This article explores the reasons for the local rejection of a proposed national park in Switzerland. Using a mixed-methods approach and resorting to qualitative and quantitative data, we follow the thread of trust issues in the participatory planning process of a protected area. Different rationales and discourses, both project-specific but also more general, influenced the opinions of local stakeholders. Connecting these different opinions was the issue of (dis)trust, which weaves in and out of prominent lines of argumentation and informs individual sentiments. The application of a multidimensional trust framework helps to understand the influence of different types of trust on protected area negotiations. We discuss how a focus on rational trust building can help to sharpen the diverse goals of contemporary protected areas with integrated conservation and economic development schemes, as well as enable the emergence of other types of trust to facilitate conservation debates

    Reproducibility of Left Ventricular Function Derived From Cardiac Magnetic Resonance and Gated 13N-Ammonia Positron Emission Tomography Myocardial Perfusion Imaging: A Head-to-Head Comparison Using Hybrid Positron Emission Tomography/Magnetic Resonance

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    RATIONALE AND OBJECTIVES Cardiac magnetic resonance (CMR) and gated 13N-ammonia positron emission tomography myocardial perfusion imaging (PET-MPI) offer accurate and highly comparable global left ventricular ejection fraction (LVEF) measurements. In addition to accuracy, however, reproducibility is crucial to avoid variations in LVEF assessment potentially negatively impacting treatment decisions. We performed a head-to-head comparison of the reproducibility of LVEF measurements derived from simultaneously acquired CMR and PET-MPI using different state-of-the-art commercially available software. MATERIALS AND METHODS 93 patients undergoing hybrid PET/MR were retrospectively included. LVEF was derived from CMR and PET-MPI at two separate core labs, using two state-of-the-art software packages for CMR (cvi42 and Medis Suite MR) and PET (QPET and CardIQ Physio). Intra- and inter-reader agreement was assessed using correlation and Bland-Altman (BA) analyses. RESULTS While intra- and inter-reader reproducibility of LVEF was high among both modalities and all software packages (r ≥ 0.87 and ICC≥0.91, all significant at p < 0.0001), LVEF derived from PET-MPI and analyzed with QPET outperformed all other analyses (intra-reader reproducibility: r = 0.99, ICC=0.99; inter-reader reproducibility: r = 0.98, ICC=1.00; Pearson correlations significantly higher than all others at p ≤ 0.0001). BA analyses showed smaller biases for LVEF derived from PET-MPI (-0.1% and +0.9% for intra-reader, -0.4% and -0.8% for inter-reader agreement) than those derived from CMR (+0.7% and +2.8% for intra-reader, -0.9% and -2.2% for inter-reader agreement) with similar results for BA limits of agreement. CONCLUSION Gated 13N-ammonia PET-MPI provides equivalent reproducibility of LVEF compared to CMR. It may offer a valid alternative to CMR for patients requiring LV functional assessment

    Reproducibility of Left Ventricular Function Derived From Cardiac Magnetic Resonance and Gated 13N-Ammonia Positron Emission Tomography Myocardial Perfusion Imaging: A Head-to-Head Comparison Using Hybrid Positron Emission Tomography/Magnetic Resonance.

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    RATIONALE AND OBJECTIVES Cardiac magnetic resonance (CMR) and gated 13N-ammonia positron emission tomography myocardial perfusion imaging (PET-MPI) offer accurate and highly comparable global left ventricular ejection fraction (LVEF) measurements. In addition to accuracy, however, reproducibility is crucial to avoid variations in LVEF assessment potentially negatively impacting treatment decisions. We performed a head-to-head comparison of the reproducibility of LVEF measurements derived from simultaneously acquired CMR and PET-MPI using different state-of-the-art commercially available software. MATERIALS AND METHODS 93 patients undergoing hybrid PET/MR were retrospectively included. LVEF was derived from CMR and PET-MPI at two separate core labs, using two state-of-the-art software packages for CMR (cvi42 and Medis Suite MR) and PET (QPET and CardIQ Physio). Intra- and inter-reader agreement was assessed using correlation and Bland-Altman (BA) analyses. RESULTS While intra- and inter-reader reproducibility of LVEF was high among both modalities and all software packages (r ≥ 0.87 and ICC≥0.91, all significant at p < 0.0001), LVEF derived from PET-MPI and analyzed with QPET outperformed all other analyses (intra-reader reproducibility: r = 0.99, ICC=0.99; inter-reader reproducibility: r = 0.98, ICC=1.00; Pearson correlations significantly higher than all others at p ≤ 0.0001). BA analyses showed smaller biases for LVEF derived from PET-MPI (-0.1% and +0.9% for intra-reader, -0.4% and -0.8% for inter-reader agreement) than those derived from CMR (+0.7% and +2.8% for intra-reader, -0.9% and -2.2% for inter-reader agreement) with similar results for BA limits of agreement. CONCLUSION Gated 13N-ammonia PET-MPI provides equivalent reproducibility of LVEF compared to CMR. It may offer a valid alternative to CMR for patients requiring LV functional assessment
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