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"Is this sedation?” – a Group Delphi process to define cut-off doses and dosing intervals for potentially sedating drugs in palliative care
Full text linkBackground In palliative care, it can be challenging to distinguish between reduced consciousness related to the illness and sedation due to a potentially sedating drug (intended, or unintended). These differentiations are important because unintended sedation requires consideration of alternative treatment options, and intentional sedation demands compliance with guidelines. The aim of the study, which was part of the consortium project iSedPall, was to determine cut-off values for drugs’ doses/dosing intervals which are expected to result in defined depth of sedation/continuous effect. Methods Group Delphi conducted in Germany with prior online survey. Based on a review of the literature, statements regarding cut-off values for drugs´ doses/dosing intervals which are expected to result in a defined depth of sedation/continuous effect were developed for 11 drugs. Consensus was defined as ≥ 75% agreement. Statements with lower agreement entered the next round of discussion. Between the rounds (5 small groups, 3 – 4 participants each), the results were presented and discussed. If necessary, statements were adapted for the following round. Participating experts were physicians, pharmacists, and nurses experienced in palliative care, mostly with over 10 years of professional experience. Results 25/30 invited experts participated in the online survey, 17 in the Group Delphi. 12/33 statements were consented in the survey. The initial questionnaire for the Group Delphi comprised 22 statements on ten drugs. After three rounds, consensus was reached for all statements, determining cut-off doses/dosing intervals for lorazepam, midazolam, diazepam, levomepromazine, haloperidol, melperone, pipamperone, propofol, dexmedetomidine, and trazodone. Conclusions This study for the first time provides evidence- and expert consensus-based data to support clinical judgements regarding sedating effects of a range of potentially sedating drugs commonly used in palliative care.Open Access funding enabled and organized by Projekt DEAL.Bundesministerium für Bildung und Forschunghttps://doi.org/10.13039/501100002347Klinikum der Universität München (6933
Von Metall Clustern zu einzelnen Atomen und über die Bildung von metall-organischen Strukturen: Eine Röntgenphotoelektronenspektroskopie Studie
No full textCatalysis plays a crucial role in the chemical industry. However, the catalysts used for industrial processes are complex and mostly consist of various materials making it challenging to distinguish the reactivity and catalytic active sites of the systems. Thus, model catalysts with increasing complexity are studied to overcome the material gap between real-application catalysts and model systems. The model catalysts studied in this work by X-ray photoelectron spectroscopy are metal clusters on a 2D material support (graphene and h-BN). The 2D materials and their Moiré structures, which evolve on Rh(111), were employed to grow ordered, almost monodisperse nanoclusters on the surface.
Starting with the investigation of Co clusters on a graphene/Rh(111) substrate, the reactive sites were narrowed down to the edges and kinks (undercoordinated sites) of the clusters using CO as a probe molecule. These reactive sites catalyzed the dissociation of CO at elevated temperatures and led to the formation of cobalt carbide and oxide. Repeating the CO adsorption experiment on the C- and O-precovered clusters revealed the blocking of edge adsorption sites by the CO dissociation products, a reduced CO adsorption capacity, and passivation of the clusters towards further CO dissociation.
Furthermore, bimetallic FePt clusters were investigated to distinguish the influence of a small amount of Pt on the catalytic performance of Fe clusters. In this context, strong metal-support interaction was observed resulting in an encapsulation of the Pt by a thin iron oxide layer which evolved due to CO dissociation upon annealing of the sample.
For the investigation of available adsorption sites on Pt clusters of various sizes, a Pt coverage gradient was prepared on h-BN/Rh(111) with cluster sizes ranging from 26 to only one atom per pore. For the larger clusters (12 – 26 Pt atoms), CO adsorption was observed at on-top and step sites of the clusters, while the formation of platinum carbonyls is observed for the smaller investigated Pt coverages (< 12 Pt atoms).
Besides these model catalytic studies, the formation and thermal stability of metal-organic frameworks using different precursor molecules and metal coordination centers were investigated. The stability of the formed network strongly depends on the preparation route. The experiments revealed that deposition of the precursor molecules before evaporation of the metal results in a higher stability of the metal-organic framework. The higher stability of this system is explained by interactions between the precursor molecules and the metal, already at low temperatures, which prevent cluster formation. Thus, the availability of metal atoms for coordination is increased. This approach could also be especially interesting in regard to the preparation of single-atom catalysts, which recently is a hot topic in the field of catalysis because sintering of the metal atoms can be prevented by the coordination to the precursor molecules preserving the catalytic activity.Katalyse ist in der chemischen Industrie nicht mehr wegzudenken. Allerdings sind die für industrielle Prozesse verwendeten Katalysatoren meist komplex und bestehen aus unterschiedlichen Materialien, was es oft schwierig macht, die Reaktivität und die katalytisch aktiven Stellen der Systeme zu identifizieren. Aus diesem Grund werden Modellkatalysatoren mit steigender Komplexität untersucht, die den Unterschied zu kommerziellen Katalysatoren überbrücken sollen. Die in dieser Arbeit mittels Röntgenphotoelektronenspektroskopie untersuchten Modellkatalysatoren sind Metallcluster auf einem 2D-Material-Support (Graphen oder h-BN). Die 2D-Materialien bilden eine Moiré-Struktur auf Rh(111) aus, die als Templat dafür sorgt, dass nahezu monodisperse und gleichmäßig verteilte Metallcluster präpariert werden konnten.
Durch die Verwendung von CO als Testmolekül wurden die reaktiven Adsorptionsplätze auf Co Clustern auf Graphen/Rh(111) bestimmt. Die Ecken und Kanten (niedrig-koordinierte Atome) der Nanopartikel stellten sich als die aktiven Zentren heraus. Erhöhung der Probentemperatur führte dazu, dass CO dissoziierte und dadurch C- und O-Atome auf der Oberfläche zurückblieben. Diese Rückstände verursachten eine reduzierte Adsorptionskapazität für CO und verhinderten weitere Dissoziation von CO durch Vergiftung der aktiven Zentren.
Des Weiteren wurden bimetallische FePt Cluster auf einem Graphen/Rh(111) Substrat untersucht, um den Einfluss von geringen Mengen Pt auf den Fe-Modellkatalysator zu testen. Durch die Adsorption von CO und dessen Dissoziation bei Temperaturerhöhung entstanden Eisenoxide. Im Zusammenhang mit dem Phänomen der „Strong Metal-Support Interactions“ führte die Präsenz der Eisenoxide zu einer Einkapselung des Platins, was die CO-Adsorptionskapazität reduzierte.
Darüber hinaus wurde ein reines Pt-Modellsystem auf h-BN/Rh(111) untersucht. Im Fokus lag dabei die Bestimmung der CO-Adsorptionsplätze auf Clustern unterschiedlicher Größe (26 bis 1 Pt Atom). Die größeren Cluster (12 – 26 Pt Atome) zeigten CO-Adsorption hauptsächlich auf on-top Positionen und den Stufen der Cluster, während für die kleineren Clustergrößen (< 12 Pt Atome) die Bildung von Platincarbonylen vorgeschlagen wurde.
Außerdem wurde die Ausbildung von metall-organischen Strukturen auf Graphen untersucht. Dafür wurden verschiedene Precursormoleküle und Metallkoordinationszentren näher betrachtet. Besonders die Präparationsroute ist ausschlaggebend für die Stabilität der ausgebildeten Strukturen: Wurden die organischen Moleküle vor dem Metall abgeschieden, konnte die Bildung von größeren Metallclustern verhindert werden, wodurch mehr Metallzentren für die Koordination zur Verfügung standen. Dieser Ansatz könnte auch von großem Interesse für die Herstellung von Einzelatom-Katalysatoren sein, welche ein weit erforschtes Feld der Katalyse darstellen, da durch die Koordination der Metallatome an die funktionalen Gruppen der Precursormoleküle das Sintern verhindert werden kann und somit die katalytische Aktivität erhalten bleibt
Synthetic Image Data Generation for Wiring Harness Component Detection Using Machine Learning †
Full text linkMachine learning is a powerful tool for computer vision tasks in manufacturing, as features are automatically extracted and a high variety of components or failures are reliably detected. A focal prerequisite for high-performing machine learning models is a database that is large in quantity as well as quality, and representative for the computer vision task in the manufacturing environment. In addition, manufacturing applications require a domain-specific dataset. Thus, we generated and integrated synthetic data for object detection using convolutional neural networks, specifically for wiring harness component detection. A synthetic data generation pipeline for images was developed and implemented. Experiments were conducted to assess the domain gap between synthetic and real images and to determine factors that are beneficial to synthetic data generation. The experimental findings demonstrate relevant training approaches to integrate synthetic data, factors that have a positive impact on training, and high-performance results comparable to using real data only.This research was supported by the project ‘Next2OEM’ of the Federal Ministry for Economic Affairs and Climate Action (BMWK) based on a decision by the German Bundestag and funded by the European Unions.Federal Ministry for Economic Affairs and Climate Action (BMWK)European Union
A Comparative Study of the Oxygen Reduction Reaction on Pt and Ag in Alkaline Media
Full text linkInvestigating the ORR under practical conditions is vital for optimizing metal–air batteries and alkaline fuel cells. Herein, we characterized Pt and Ag gas diffusion electrodes (GDE) in a GDE half‐cell in high alkaline concentrations at elevated temperatures by polarization curves and electrochemical impedance spectroscopy (EIS) combined with the distribution of relaxation times (DRT) analysis. The Pt catalyst's polarization curve displays substantial losses below 0.82 V vs. RHE. The DRT analysis reveals significantly increased charge transfer resistance and a decelerated ORR at that potential. RRDE measurements attributed the polarization loss observed for Pt catalysts to increased peroxide formation in this potential region triggered by the desorption of oxygenated species. Therefore, the ORR activity of Ag exceeds some of the here‐used Pt catalysts at high current densities. This work combines the benefits of the RRDE and the GDE half‐cell to study catalysts and identify the reaction mechanisms under conditions relevant to practical fuel cells and batteries. Moreover, the DRT analysis is introduced as an analytical tool to determine the charge transfer resistance contribution and the corresponding frequency of the ORR.In this study, the oxygen reduction reaction on Pt and Ag is investigated in alkaline media using fundamental and technical approaches. Strong differences at high currents are observed, leading to better performance for Ag under certain conditions. The underlying mechanistic electrocatalytic processes responsible for these phenomena are investigated and detected. imageKIT Future Field
Analyzing performance portability for a SYCL implementation of the 2D shallow water equations
Full text linkSYCL is an open standard for targeting heterogeneous hardware from C++. In this work, we evaluate a SYCL implementation for a discontinuous Galerkin discretization of the 2D shallow water equations targeting CPUs, GPUs, and also FPGAs. The discretization uses polynomial orders zero to two on unstructured triangular meshes. Separating memory accesses from the numerical code allow us to optimize data accesses for the target architecture. A performance analysis shows good portability across x86 and ARM CPUs, GPUs from different vendors, and even two variants of Intel Stratix 10 FPGAs. Measuring the energy to solution shows that GPUs yield an up to 10x higher energy efficiency in terms of degrees of freedom per joule compared to CPUs. With custom designed caches, FPGAs offer a meaningful complement to the other architectures with particularly good computational performance on smaller meshes. FPGAs with High Bandwidth Memory are less affected by bandwidth issues and have similar energy efficiency as latest generation CPUs.Open Access funding enabled and organized by Projekt DEAL.Deutsche Forschungsgemeinschafthttp://dx.doi.org/10.13039/501100001659Universität Bayreuth (3145
Impact of non-contrast-enhanced imaging input sequences on the generation of virtual contrast-enhanced breast MRI scans using neural network
Full text linkObjective To investigate how different combinations of T1-weighted (T1w), T2-weighted (T2w), and diffusion-weighted imaging (DWI) impact the performance of virtual contrast-enhanced (vCE) breast MRI. Materials and methods The IRB-approved, retrospective study included 1064 multiparametric breast MRI scans (age: 52 ± 12 years) obtained from 2017 to 2020 (single site, two 3-T MRI). Eleven independent neural networks were trained to derive vCE images from varying input combinations of T1w, T2w, and multi-b-value DWI sequences (b-value = 50–1500 s/mm 2 ). Three readers evaluated the vCE images with regard to qualitative scores of diagnostic image quality, image sharpness, satisfaction with contrast/signal-to-noise ratio, and lesion/non-mass enhancement conspicuity. Quantitative metrics (SSIM, PSNR, NRMSE, and median symmetrical accuracy) were analyzed and statistically compared between the input combinations for the full breast volume and both enhancing and non-enhancing target findings. Results The independent test set consisted of 187 cases. The quantitative metrics significantly improved in target findings when multi-b-value DWI sequences were included during vCE training ( p 0.05) were observed for the quantitative metrics on the full breast volume when comparing input combinations including T1w. Using T1w and DWI acquisitions during vCE training is necessary to achieve high satisfaction with contrast/SNR and good conspicuity of the enhancing findings. The input combination of T1w, T2w, and DWI sequences with three b-values showed the best qualitative performance. Conclusion vCE breast MRI performance is significantly influenced by input sequences. Quantitative metrics and visual quality of vCE images significantly benefit when multi b-value DWI is added to morphologic T1w-/T2w sequences as input for model training. Key Points Question How do different MRI sequences impact the performance of virtual contrast-enhanced (vCE) breast MRI? Findings The input combination of T1-weighted, T2-weighted, and diffusion-weighted imaging sequences with three b-values showed the best qualitative performance. Clinical relevance While in the future neural networks providing virtual contrast-enhanced images might further improve accessibility to breast MRI, the significant influence of input data needs to be considered during translational research. Graphical AbstractBayerisches Staatsministerium für Wissenschaft und Kunsthttp://dx.doi.org/10.13039/50110002171
The Effect of Hearing Aid Amplification on Gait Parameters: A Pilot Study Using Ear-Worn Motion Sensors
Full text linkBackground/Objectives: Hearing loss, particularly in older adults, is associated with reduced physical functioning; increased fall risk; and altered gait patterns, including slower walking speed and shorter step length. While the underlying mechanisms are not fully understood, one possibility is that these gait changes result from an additional cognitive load due to hearing difficulties. Prior research suggests that hearing aids may improve balance; however, their impact on gait remains less well explored. Methods: This study investigated gait parameters in individuals with hearing loss as they walked with and without hearing aid amplification under different dual-task conditions. Additionally, we showed the potential of ear-worn sensors for detecting relevant gait changes. To achieve this, we used a hearing-aid-integrated accelerometer and our open-source EarGait framework comprising gait-related algorithms specifically developed for ear-worn sensors. Results: Our findings revealed no significant differences in gait velocity or step length between the unaided and aided conditions. For stride time, we observed a significant interaction effect; however, the effect size was negligible. The dual-task costs were lower than in previous reports, indicating that the applied dual-task paradigm did not induce the expected cognitive demand. The ear-worn gait analysis system showed strong performance compared to foot-worn sensors. Conclusions: Our findings indicate that in controlled, low-cognitive-demand settings, hearing aid amplification does not affect gait performance and, therefore, neither hinders nor improves walking performance. Additionally, the high accuracy of the ear-worn gait analysis system highlights the strong potential of ear-mounted wearable devices (“earables”) for real-world mobility assessments. Future research should explore more complex real-world conditions to better understand the impact of hearing aids on walking behavior. Our proposed earable-based system offers a promising tool for continuous, unobtrusive gait monitoring in everyday environments.This project was a joint collaboration between the Machine and Data Analytics (MaD) Lab, Friedrich-Alexander Universität Erlangen-Nürnberg, and Sivantos GmbH. The MaD Lab received funding from Sivantos GmbH under a research and development contract.Machine and Data Analytics (MaD) LabFriedrich-Alexander Universität Erlangen-NürnbergSivantos Gmb
Quantum Fields and the Cosmological Constant
Full text linkIt has been shown that if one solves self-consistently the semiclassical Einstein equations in the presence of a quantum scalar field, with a cutoff on the number of modes, spacetime become flatter when the cutoff increases. Here, we extend the result to include the effect of fields with spin 0, 1/2, 1 and 2. With minor adjustments, the main result persists. Remarkably, one can have positive curvature even if the cosmological constant in the bare action is negative.This work was supported by a grant from the Simons Foundation (grant no. 1034867, Dittrich).Simons Foundatio
Quantum field theory of black hole perturbations with backreaction IV: spherically symmetric 2nd order Einstein–Maxwell sector in generalised gauges
Full text linkIn previous papers of this series we analysed the reduced phase space approach to perturbations of Einstein–Maxwell theory to second order around spherically symmetric backgrounds in the Gullstrand Painlevé gauge and confirmed consistency with previous approaches. In the analysis, we defined the gauge invariant variables non-perturbatively and took backreaction effects explicitly into account. In this paper, as a non-trivial consistency check, we generalize the results and show that a similar analysis is possible for other choices of gauge for the background variables. We obtain the same structure for the reduced Hamiltonian that contains the well known Regge–Wheeler and Zerilli potentials. Possible applications of this generalization are discussed.Open Access funding enabled and organized by Projekt DEAL.Hanns-Seidel-Stiftunghttps://doi.org/10.13039/501100016117Friedrich-Alexander-Universität Erlangen-Nürnberg (1041
Envisioning Global Education in Rwanda: Contributions from Secondary School Teachers
Full text linkGlobal education (GE) has become important in education due to heightened global interconnectedness and interdependence, with its incorporation into school materials aimed at preparing learners to navigate global challenges. In implementing GE, teachers are considered critical agents to transform normative GE into knowledge in classrooms. This study examines Rwandese teachers’ knowledge, awareness, and perceptions of challenges they face in implementing GE in schools. In a quantitative design, 208 teachers from 15 participating secondary schools completed a survey. The study findings reveal that the teachers had moderate to high levels of knowledge and awareness of global education, with most of the teachers recognising GE to be important in preparing learners for the future and stated the need to incorporate it within the curriculum in Rwanda. This study underscores the need for teacher training and professional development to enhance GE integration, and the provision of necessary resources and materials to enable the implementation of GE in schools in Rwanda.The work of Dalila Pinto Coelho was supported by national funding from FCT—Fundação para a Ciência e a Tecnologia, through the research contract within the Individual Scientific Employment Stimulus Programe [ref. n.º 2023.09356.CEECIND—DOI https://doi.org/10.54499/2023.09356.CEECIND/CP2878/CT0005]; and by FCT, through the multi-year funding of CIIE [grants n.º UIDB/00167/2020, UIDP/00167/2020 and UID/00167:Centre for Research and Intervention in Education—CIIE], and of the RESTART funding [2023.00069.RESTART].FCT—Fundação para a Ciência e a TecnologiaIndividual Scientific Employment Stimulus ProgrameFCTmulti-year funding of CIIECentre for Research and Intervention in Education—CIIERESTAR