60 research outputs found

    Electroless Nanoplating of Pd−Pt Alloy Nanotube Networks: Catalysts with Full Compositional Control for the Methanol Oxidation Reaction

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    Due to its simplicity, flexibility and conformity, electroless plating presents itself as an attractive route towards functional metal nanostructures. Despite the importance for creating multimetallic materials with enhanced properties, the complex interactions between the components in electroless plating baths make alloy formations a challenging objective. In this work, we outline an electroless plating strategy fabricating Pd−Pt alloy nanomaterials, which is based on arbitrarily miscible plating baths for the individual metals. To demonstrate the excellent nanoscale conformity and homogeneity of our plating system, we apply it to ion track‐etched polymer templates with large inner surfaces as ambitious substrates, resulting in the formation of 3D free‐standing PdₓPt₁₀₀₋ₓ‐nanotube‐networks (NTNWs). Based on the electro‐oxidation of methanol as a model reaction, we utilize the compositional freedom provided by our syntheses for optimizing the catalytic performance of our metal NTNWs, which heavily depends on the Pd−Pt ratio. Within our system, the highest surface normalized activity was found for the Pd₂₀Pt₈₀ NTNW, reaching more than a two‐fold increase of the peak current density in comparison to pure Pt. Overall, our reaction system provides a versatile toolkit for fabricating intricate Pd−Pt nanostructures of arbitrary elemental composition, and constitutes a starting point for designing new electroless alloy plating baths

    Point-of-care lung ultrasound in COVID-19 patients: inter- and intra-observer agreement in a prospective observational study

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    With an urgent need for bedside imaging of coronavirus disease 2019 (COVID-19), this study's main goal was to assess inter- and intraobserver agreement in lung ultrasound (LUS) of COVID-19 patients. In this single-center study we prospectively acquired and evaluated 100 recorded ten-second cine-loops in confirmed COVID-19 intensive care unit (ICU) patients. All loops were rated by ten observers with different subspeciality backgrounds for four times by each observer (400 loops overall) in a random sequence using a web-based rating tool. We analyzed inter- and intraobserver variability for specific pathologies and a semiquantitative LUS score. Interobserver agreement for both, identification of specific pathologies and assignment of LUS scores was fair to moderate (e.g., LUS score 1 Fleiss' kappa =0.27; subpleural consolidations Fleiss' kappa =0.59). Intraobserver agreement was mostly moderate to substantial with generally higher agreement for more distinct findings (e.g., lowest LUS score 0 vs. highest LUS score 3 (median Fleiss' kappa =0.71 vs. 0.79) or air bronchograms (median Fleiss' kappa =0.72)). Intraobserver consistency was relatively low for intermediate LUS scores (e.g. LUS Score 1 median Fleiss' kappa =0.52). We therefore conclude that more distinct LUS findings (e.g., air bronchograms, subpleural consolidations) may be more suitable for disease monitoring, especially with more than one investigator and that training material used for LUS in point-of-care ultrasound (POCUS) should pay refined attention to areas such as B-line quantification and differentiation of intermediate LUS scores

    Developing a Cloud Scheme With Prognostic Cloud Fraction and Two Moment Microphysics for ECHAM‐HAM

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    We present a new cloud scheme for the ECHAM‐HAM global climate model (GCM) that includes prognostic cloud fraction and allows for subsaturation and supersaturation with respect to ice separately in the cloud‐free and cloudy air. Stratiform clouds form by convective detrainment, turbulent vertical diffusion, and large‐scale ascent. For each process, the corresponding cloud fraction is calculated, and the individual updraft velocities are used to determine cloud droplet/ice crystal number concentrations. Further, convective condensate is always detrained as supercooled cloud droplets at mixed‐phase temperatures (between 235 and 273 K), and convectively detrained ice crystal number concentrations are calculated based on the updraft velocity. Finally, the new scheme explicitly calculates condensation/evaporation and deposition/sublimation rates for phase‐change calculations. The new cloud scheme simulates a reasonable present‐day climate, reduces the previously overestimated cirrus cloud fraction, and in general improves the simulation of ice clouds. The model simulates the observed in‐cloud supersaturation for cirrus clouds, and it allows for a better representation of the tropical to extra‐tropical ratio of the longwave cloud radiative effect. Further, the ice water path, the ice crystal number concentrations, and the supercooled liquid fractions in mixed‐phase clouds agree better with observations in the new model than in the reference model. Ice crystal formation is dominated by the liquid‐origin processes of convective detrainment and homogeneous freezing of cloud droplets. The simulated ice clouds strongly depend on model tuning choices, in particular, the enhancement of the aggregation rate of ice crystals.ISSN:1942-246

    Developing a Cloud Scheme With Prognostic Cloud Fraction and Two Moment Microphysics for ECHAM‐HAM

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    Abstract We present a new cloud scheme for the ECHAM‐HAM global climate model (GCM) that includes prognostic cloud fraction and allows for subsaturation and supersaturation with respect to ice separately in the cloud‐free and cloudy air. Stratiform clouds form by convective detrainment, turbulent vertical diffusion, and large‐scale ascent. For each process, the corresponding cloud fraction is calculated, and the individual updraft velocities are used to determine cloud droplet/ice crystal number concentrations. Further, convective condensate is always detrained as supercooled cloud droplets at mixed‐phase temperatures (between 235 and 273 K), and convectively detrained ice crystal number concentrations are calculated based on the updraft velocity. Finally, the new scheme explicitly calculates condensation/evaporation and deposition/sublimation rates for phase‐change calculations. The new cloud scheme simulates a reasonable present‐day climate, reduces the previously overestimated cirrus cloud fraction, and in general improves the simulation of ice clouds. The model simulates the observed in‐cloud supersaturation for cirrus clouds, and it allows for a better representation of the tropical to extra‐tropical ratio of the longwave cloud radiative effect. Further, the ice water path, the ice crystal number concentrations, and the supercooled liquid fractions in mixed‐phase clouds agree better with observations in the new model than in the reference model. Ice crystal formation is dominated by the liquid‐origin processes of convective detrainment and homogeneous freezing of cloud droplets. The simulated ice clouds strongly depend on model tuning choices, in particular, the enhancement of the aggregation rate of ice crystals

    Scripts for the publication "Higher climate sensitivity and stronger cloud feedbacks in ECHAM6.3 with a prognostic cloud fraction scheme"

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    <p>This repository contains the scripts for the paper:</p><p>"Muench, S., Neubauer, D. and Lohmann, U.: Higher climate sensitivity and stronger cloud feedbacks in ECHAM6.3 with a prognostic cloud fraction scheme"</p><p>Each directory contains the scripts to reproduce the figures in our paper.</p><p>Note that the data are to be found in the accompanying package (https://doi.org/10.5281/zenodo.10057458)</p&gt

    Data for the publication "Higher climate sensitivity and stronger cloud feedbacks in ECHAM6.3 with a prognostic cloud fraction scheme"

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    <p>This repository contains the data for the paper:</p><p>"Muench, S., Neubauer, D. and Lohmann, U.: Higher climate sensitivity and stronger cloud feedbacks in ECHAM6.3 with a prognostic cloud fraction scheme"</p><p>Each directory contains the model data to reproduce the figures in our paper.</p><p>Note that the scripts are to be found in the accompanying package (https://doi.org/10.5281/zenodo.10057465)</p&gt

    Time trends in the regional distribution of physicians, nurses and midwives in Europe

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    Background: Country-level data suggest large differences in the supply of health professionals among European countries. However, little is know about the regional supply of health professionals taking a cross-country comparative perspective. The aim of the study was to analyse the regional distribution of physicians, nurses and midwives in the highest and lowest density regions in Europe and examine time trends. Methods: We used Eurostat data and descriptive statistics to assess the density of physicians, nurses and midwives at national and regional levels (Nomenclature of Territorial Units for Statistics (NUTS) 2 regions) for 2017 and time trends (2005–2017). To ensure cross-country comparability we applied a set of criteria (working status, availability over time, geographic availability, source). This resulted in 14 European Union (EU) countries and Switzerland being available for the physician analysis and eight countries for the nurses and midwives analysis. Density rates per population were analysed at national and NUTS 2 level, of which regions with the highest and lowest density of physicians, nurses and midwives were identified. We examined changes over time in regional distributions, using percentage change and Compound Annual Growth Rate (CAGR). Results: There was a 2.4-fold difference in the physician density between the highest and lowest density countries (Austria national average: 513, Poland 241.6 per 100,000) and a 3.5-fold difference among nurses (Denmark: 1702.5, Bulgaria: 483.0). Differences by regions across Europe were higher than cross-country variations and varied up to 5.5-fold for physicians and 4.4-fold for nurses/midwives and did not improve over time. Capitals and/or major cities in all countries showed a markedly higher supply of physicians than more sparsely populated regions while the density of nurses and midwives tended to be higher in more sparsely populated areas. Over time, physician rates increased faster than density levels of nurses and midwives. Conclusions: The study shows for the first time the large variation in health workforce supply at regional levels and time trends by professions across the European region. This highlights the importance for countries to routinely collect data in sub-national geographic areas to develop integrated health workforce policies for health professionals at regional levels.TU Berlin, Open-Access-Mittel – 202

    Time trends in the regional distribution of physicians, nurses and midwives in Europe

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    Winkelmann J, Muench U, Maier CB. Time trends in the regional distribution of physicians, nurses and midwives in Europe. BMC Health Services Research. 2020;20(1): 937.**Background** Country-level data suggest large differences in the supply of health professionals among European countries. However, little is know about the regional supply of health professionals taking a cross-country comparative perspective. The aim of the study was to analyse the regional distribution of physicians, nurses and midwives in the highest and lowest density regions in Europe and examine time trends. **Methods** We used Eurostat data and descriptive statistics to assess the density of physicians, nurses and midwives at national and regional levels (Nomenclature of Territorial Units for Statistics (NUTS) 2 regions) for 2017 and time trends (2005–2017). To ensure cross-country comparability we applied a set of criteria (working status, availability over time, geographic availability, source). This resulted in 14 European Union (EU) countries and Switzerland being available for the physician analysis and eight countries for the nurses and midwives analysis. Density rates per population were analysed at national and NUTS 2 level, of which regions with the highest and lowest density of physicians, nurses and midwives were identified. We examined changes over time in regional distributions, using percentage change and Compound Annual Growth Rate (CAGR). **Results** There was a 2.4-fold difference in the physician density between the highest and lowest density countries (Austria national average: 513, Poland 241.6 per 100,000) and a 3.5-fold difference among nurses (Denmark: 1702.5, Bulgaria: 483.0). Differences by regions across Europe were higher than cross-country variations and varied up to 5.5-fold for physicians and 4.4-fold for nurses/midwives and did not improve over time. Capitals and/or major cities in all countries showed a markedly higher supply of physicians than more sparsely populated regions while the density of nurses and midwives tended to be higher in more sparsely populated areas. Over time, physician rates increased faster than density levels of nurses and midwives. **Conclusions** The study shows for the first time the large variation in health workforce supply at regional levels and time trends by professions across the European region. This highlights the importance for countries to routinely collect data in sub-national geographic areas to develop integrated health workforce policies for health professionals at regional levels
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