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Duration of mild acute SARS-CoV-2 infections with Omicron depending on previous vaccinations and infections : using data of the German DigiHero cohort study from post-pandemic winters 2022/2023 and 2023/2024
No full textObjectives: Protection against severe course of SARS-CoV-2 infection after COVID-19 vaccination or infec
tion was extensively studied. It is unknown whether this effect also translates into shortened duration of mild infections. We assessed the duration of symptoms depending on vaccination status and previous SARS- CoV-2 infections among individuals with a mild course of infection.
Methods: For two post-pandemic winters (2022/2023 and 2023/2024), in total 13,615 participants of the German DigiHero study reported their SARS-CoV-2 infections from September to March. Via negative bi
nomial regression adjusting for sociodemographic factors, we studied the association of infection duration (days with symptoms and in bed) with number of vaccinations, prior SARS-CoV-2 infections, and time since last vaccination/and infection.
Results: We noted no major differences in infection duration depending on the number of vaccinations and time since last infection for short mild infections (≤21 days with symptoms). Per 6 months since the last vaccination, symptom duration and days spent in bed increased by 2 % and 4 %. The risk of long mild SARS-CoV- 2 infections (> 21 days with symptoms) was higher for individuals with no prior SARS-CoV-2 infection (Odds Ratio: 1.98; 95 % confidence interval [1.43; 2.76]), but not for vaccinations (OR: 0.98; 95 % CI [0.74; 1.33]).
Conclusions: There was no indication of reduced duration of symptoms during short mild infections de
pending on the number of vaccinations and time since the last SARS-CoV-2 vaccination or infection. A prior SARS-CoV-2 infection was protective against prolonged disease in mild SARS-CoV-2 infections
Of individual and collaborative experiences: training and learning in immersive environments for medical education
No full textThe ongoing digital transformation is fundamentally reshaping the landscape of medical education. Mixed Reality (MR) technologies contribute significantly to these advancements by introducing immersive simulations that enhance user engagement and learning outcomes. However, designing such systems for educational purposes involves addressing interdisciplinary challenges. A crucial aspect of this process is understanding students’ needs and the pedagogical framework while integrating technological considerations.
Therefore, the overarching question in this thesis is: How can immersive experiences be designed to enrich medical education? The first part of this work addresses the design of virtual environments by exploring the impact of visual and interactive fidelity in medical task simulations. This investigation provides a practical framework for balancing realism, development effort, and user needs. The findings indicate that higher fidelity enhances the user experience, while no significant differences in task performance were observed across the selected interaction modalities.
The second part focuses on the field of anatomical education and introduces a fully immersive virtual environment designed to foster individual knowledge construction. Through interdisciplinary collaboration, a system was developed that leverages natural hand interaction to enhance understanding of embryonic heart development. The results indicate that effective visualizations in MR must strike a balance between simplicity and sufficient contextual detail, while interactions should cater to varying levels of user expertise and spatial reasoning. Furthermore, when this application was used as a supplementary learning tool during exam preparation by medical students, it demonstrated a measurable knowledge gain. Building on these insights, the third part focuses on the development of collaborative approaches across different MR systems and compares them to individual learning applications. The study concluded that there were no significant differences in educational outcomes between individual learning environments and collaborative setups, as both effectively supported knowledge acquisition for embryonic heart development. While individual environments facilitated learning with greater user control, collaborative approaches enhanced social presence and teamwork dynamics. The final part extends the focus to advanced practical training in the context of liver surgery. A cross-modality MR-based platform was developed to explore different modalities and learning approaches using curated clinical use cases. A study involving teachers and students demonstrated the potential of this cross-modality system to effectively support both collaborative and explorative learning in liver surgery education.
This thesis explores how user-centered principles can guide the design of MR systems for medical education, addressing technical and pedagogical challenges through varied technologies, learning approaches, and interaction principles. It further advances understanding by examining human-computer interaction methods and interaction design decisions to improve MR-based educational tools.Die fortschreitende digitale Transformation verändert die Landschaft der medizinischen Ausbildung grundlegend. Mixed-Reality-Technologien (MR) tragen wesentlich zu diesen Fortschritten bei, indem sie immersive Simulationen ermöglichen, die sowohl die Motivation der Lernenden erhöhen als auch das Lernen verbessern. Die Entwicklung solcher Systeme erfordert jedoch die Bewältigung interdisziplinärer Herausforderungen.
Ein zentraler Aspekt dabei ist das Verständnis der Bedürfnisse von Lernenden und der pädagogischen Rahmenbedingungen, während gleichzeitig technologische Überlegungen einbezogen werden müssen. Die zentrale Fragestellung dieser Arbeit lautet daher: Wie können immersive Erlebnisse gestaltet werden, um die medizinische Ausbildung zu bereichern? Der erste Teil dieser Arbeit beschäftigt sich mit der Gestaltung virtueller Umgebungen, indem der Einfluss visueller und interaktiver Qualitäten in medizinischen Aufgabensimulationen untersucht wird. Diese Untersuchung liefert einen praxisorientierten Rahmen, um Realismus, Entwicklungsaufwand und Benutzerbedürfnisse in Einklang zu bringen. Die Ergebnisse zeigen, dass eine höhere visuelle Qualität die Nutzererfahrung verbessert, während bei den gewählten Interaktionsmodalitäten keine signifikanten Unterschiede in der Aufgabenleistung festgestellt wurden. Der zweite Teil konzentriert sich auf den Bereich der anatomischen Ausbildung und stellt eine vollständig immersive virtuelle Umgebung vor, die darauf ausgelegt ist, individuelle Wissensbildung zu fördern. In einer interdisziplinären Zusammenarbeit wurde ein System entwickelt, das natürliche Interaktionen nutzt, um das Verständnis der embryonalen Herzentwicklung zu verbessern. Die Ergebnisse zeigen, dass effektive Visualisierungen in MR ein Gleichgewicht zwischen Einfachheit und ausreichendem kontextuellem Detail finden müssen, während die Interaktionen auf unterschiedliche Kompetenzstufen und räumliches Vorstellungsvermögen der Nutzer abgestimmt sein sollten. Darüber hinaus wurde bei der Verwendung dieses Systems als unterstützendes Lernwerkzeug während der Prüfungsphase von Medizinstudierenden ein messbarer Wissenszuwachs festgestellt.
Aufbauend auf diesen Erkenntnissen befasst sich der dritte Teil mit der Entwicklung kollaborativer Ansätze auf verschiedenen MR-Systemen und vergleicht diese mit individuellen Lernanwendungen. Die Studie ergab keine signifikanten Unterschiede in den Lernergebnissen zwischen individuellen Lernumgebungen und kollaborativen Ansätzen, jedoch unterstützten beide effektiv die Wissensvermittlung zur embryonalen Herzentwicklung. Während individuelle Umgebungen das Lernen durch mehr Benutzerkontrolle erleichterten, verbesserten kollaborative Ansätze die soziale Interaktion und die Teamdynamik.
Der abschließende Teil erweitert den Fokus auf einen fortgeschrittenen Ausbildungszweig im Kontext der Leberchirurgie. Eine plattformübergreifende MR-basierte Anwendung wurde entwickelt, um verschiedene Modalitäten und Lernansätze mithilfe kuratierter klinischer Anwendungsfälle zu erforschen. Eine Studie mit Lehrenden und Studierenden zeigte das Potenzial dieses plattformübergreifenden Systems, um sowohl kollaboratives als auch exploratives Lernen in der Leberchirurgie-Ausbildung effektiv zu unterstützen. Diese Arbeit untersucht, wie nutzerzentrierte Prinzipien die Gestaltung von MR-Systemen für die medizinische Ausbildung leiten können, indem technische und pädagogische Herausforderungen durch unterschiedliche Technologien, Lernansätze und Interaktionsprinzipien adressiert werden. Sie erweitert das Verständnis, indem Methoden und Interaktionsdesign-Entscheidungen analysiert werden, um
MR-basierte Systeme für die medizinische Ausbildung zu verbessern.Literaturverzeichnis: Seite 209-24
Patients' perceptions of artificial intelligence acceptance, challenges, and use in medical care : qualitative study
No full textBackground: Artificial intelligence (AI) is increasingly used in medical care, particularly in the areas of image recognition and processing. While its practical use in other areas is still limited, an understanding of patients’ needs is essential for the practical and sustainable implementation of AI, which could further acceptance of new innovations.
Objective: The objective of this study was to explore patients’ perceptions toward acceptance, challenges of implementation, and potential applications of AI in medical care.
Methods: The study used a qualitative research design. To capture a broad range of patient perspectives, we conducted semistructured focus groups (FGs). As a stimulus for the FGs and as an introduction to the topic, we presented a video defining AI and showing 3 potential AI applications in health care. Participants were recruited from different locations in the regions of Halle (Saale) and Erlangen, Germany; all but one group were from outpatient settings. We analyzed the data using a content analysis approach.
Results: A total of 35 patients (13 female and 22 male; age: range 23-92, median 50 years) participated in 6 focus groups. They highlighted that AI acceptance in medical care could be improved through user-friendly applications, clear instructions, feedback mechanisms, and a patient-centered approach. Perceived key barriers included data protection concerns, lack of human oversight, and profit-driven motives. Perceived challenges and requirements for AI implementation involved compatibility, training of end users, environmental sustainability, and adherence to quality standards. Potential AI application areas identified were diagnostics, image and data processing, and administrative tasks, though participants stressed that AI should remain a support tool, not an autonomous system. Psychology was an area where its use was opposed due to the need for human interaction.
Conclusions: Patients were generally open to the use of AI in medical care as a support tool rather than as an independent decision-making system. Acceptance and successful use of AI in medical care could be achieved if it is easy to use, adapted to individual characteristics of the users, and accessible to everyone, with the primary aim of enhancing patient well-being. AI in health care requires a regulatory framework, quality standards, and monitoring to ensure socially fair and environmentally sustainable development. However, the successful implementation of AI in medical practice depends on overcoming the mentioned challenges and addressing user needs
Redox status-selective imaging of iron in vegetative and pathogenic fungal cells using fluorescent dyes synthesized via simple chemical reactions
No full textIron plays a prominent role in various biological processes and is an essential element in almost all organisms, including plant-pathogenic fungi. As a transition element, iron occurs in two redox states, Fe2+ and Fe3+, the transition between which generates distinct reactive oxygen species (ROS) such as H2O2, OH− anions, and toxic OH· radicals. Thus, the redox status of Fe determines ROS formation in pathogen attack and plant defense and governs the outcome of pathogenic interactions. Therefore, spatially resolved visualization of Fe2+ and Fe3+ are essential to understand microbial pathogenesis. Here, we report a simple method for synthesis of the redox-state-selective dyes pyrene-tetramethyl piperidinyl oxyl (p-TEMPO) and 4-(4-methylpiperazine-1)-7-nitrobenz-2-oxa-1,3-diazole (MPNBD) for fluorescence microscopy-based imaging of Fe2+ and Fe3+ ions. Using these dyes, the occurrence and spatial distribution of Fe2+ and Fe3+ ions in vegetative and pathogenic hyphae of the hemibiotrophic maize anthracnose fungus Colletotrichum graminicola are shown
Vertrauen ist gut, Kontrolle ist besser? – Der globale Trend zu Verschärfungen von Ausfuhrkontrollen bei Dual-Use-Gütern
No full textZuletzt ließ sich ein globaler Trend zu Verschärfungen von Ausfuhrkontrollen bei Dual-Use-Gütern beobachten. Insbesondere in der EU, den USA und China gab es rechtliche Neuerungen, die der Beitrag vergleichend untersucht. Die Untersuchung stellt dabei zunächst die jüngsten Entwicklungen dar und vergleicht diese dann anhand der mit den Ausfuhrkontrollen verfolgten Ziele, der Bedeutung multi- und minilateraler internationaler Zusammenarbeit sowie ihrer teils extraterritorialen Reichweite. Schließlich wird die völkerrechtliche Zulässigkeit der Verschärfungen anhand des völkergewohnheitsrechtlichen Interventionsverbots und des WTO-Rechts untersucht
Changes in chronic graft-versus-host disease treatment over time : a15-years survey within allogeneic hematopoietic stem cell transplant centers in Germany, Austria, and Switzerland
No full textBackground
Chronic graft-versus-host disease (cGVHD) represents a major complication after allogeneic stem cell transplantation (alloHSCT). In 2009 and 2018 a survey among German, Austrian, and Swiss transplant centers showed a homogeneous 1st-line treatment practice, while 2nd-line treatment as well as management of progressive onset type and bronchiolitis obliterans syndrome (BOS) displayed significant heterogeneity. Since the last survey, ruxolitinib (rux) has been approved and other new agents are explored in treatment of cGVHD.
Objective
We conducted a follow-up survey in 2024 to document the impact of recent approvals and new agents on treatment pattern focusing on management of 2nd-line treatment, progressive onset type, BOS, and sclerotic manifestations.
Study design
A paper-and-pencil-based questionnaire was sent electronically to 60 German speaking centers performing alloHSCT. 20 centers responded, representing 45% of the patients receiving an alloHSCT in 2023 in Germany, Austria, and Switzerland.
Results
In 1st-line treatment of classic standard risk cGVHD, single agent prednisone represents standard of care (14/20 centers) which may be combined with calcineurin inhibitor (CNI) (4/20), while rux is used in selected cases only. In 2nd-line treatment rux is now used by the majority of centers (19/20). In the presence of cytopenia, rux remains the preferred agent (12/20) while use of extracorporeal photopheresis (ECP) is considered by 8 of 20 centers. In case of active infections, ECP is preferred by 15 of 20 centers and both agents are regarded as steroid-sparing agents in 2nd-line treatment of steroid-dependent cGVHD. Rux would be applied in the presence of active infections by 5/20 centers only. Moreover, rux (15/20) and ECP (6/20) are also preferred treatment modalities in treatment of progressive onset cGVHD. For BOS, systemic and inhalative corticosteroids, montelukast and azithromycin (FAM, 13/20), rux (15/20), ECP (17/20) and CNI (10/20) are frequently applied agents, while abatacept (8/20), belumosudil (7/20), imatinib (5/20), mycophenolate mofetil (MMF) (5/20), everolimus (4/20) and ibrutinib (3/20) are used as salvage options in selected patients only. In case of new sclerotic manifestations after failure of 2nd-line treatment including steroids, CNI and rux, most centers would use ECP (14/20), whereas subsequent or alternative salvage treatment of sclerotic manifestations remains heterogenous comprising belumosudil (13/20), ibrutinib (5/20), imatinib (5/20), rituximab (4/20), cyclosporine (3/20), tacrolimus (3/20), everolimus (3/20), sirolimus (3/20), methotrexate (3/20) and MMF (3/20). The preferred taper sequence of immunosuppressive agents in case of response applied in 12/20 centers is initial taper of steroids, followed by taper of CNI and final termination of rux.
Conclusion
The survey documents the effect of evidence and approval on clinical care with single agent prednisone representing the standard of care in 1st-line treatment while rux combined with steroids defines the new standard for 2nd-line treatment of cGVHD. ECP is used in case of contraindication for rux and both agents are also used in progressive onset cGVHD. In contrast, treatment of BOS and sclerotic cGVHD beyond 2nd-line treatment remains heterogeneous with new agents being integrated in the treatment landscape
Multifunctional steep-slope spintronic transistors with spin-gapless-semiconductor or spin-gapped-metal electrodes
No full textSpin-gapless semiconductors (SGSs) are emerging as a promising class of materials for spintronic applications, offering unique opportunities to realize functionalities beyond conventional electronics. In this work, we propose a concept of multifunctional spintronic field-effect transistors (FETs) using SGSs and/or spin-gapped metals (SGMs) as source and drain electrodes. These devices operate similarly to metal-semiconductor Schottky-barrier FETs, where a potential barrier forms between the SGS (or SGM) electrode and the intrinsic semiconducting channel; however, unlike conventional Schottky-barrier FETs, our proposed devices exploit the distinctive spin-dependent transport properties of SGS and SGM electrodes to achieve sub-60-mV/dec switching, significantly surpassing the 60 mV/dec subthreshold swing (SS) limit in traditional MOSFETs, thereby enabling low-voltage operation. Additionally, the proposed FETs exhibit a nonlocal giant magnetoresistance (GMR) effect, enhancing functionality by enabling nonvolatile memory capabilities. The incorporation of SGMs also introduces a negative differential resistance effect with an ultrahigh peak-to-valley current ratio, further expanding the device’s multifunctionality. Two-dimensional (2D) nanomaterials provide a promising platform for realizing these advanced FETs. We perform a comprehensive screening of the computational 2D materials database to identify suitable SGS and SGM candidates. Among the materials identified, several exhibit Curie temperatures significantly above room temperature, ensuring robust ferromagnetic properties for practical applications. For device simulations, we select VS2 as the SGS material and, as a proof of concept, employ a nonequilibrium Green’s function method combined with density functional theory to simulate the transfer (D-G) and output (D-D) characteristics of a vertical VS2/Ga2O2 heterojunction FET. Our calculations predict a remarkably low SS of 20 mV/dec, a high on-off ratio of 108, and a significant nonlocal GMR effect, demonstrating the potential of these devices for low-power, high-performance logic and memory applications
Engineering "Meso-Atom" bonding : honeycomb-network transitions in reticular liquid crystals
No full textA library of rod-like bolapolyphiles with sticky hydrogen-bonded glycerol groups at their ends and having highly branched side chains with a carbosilane-based four-way branching point, all based on the same oligo(phenylene ethynylene) core, has been synthesized and investigated. For these compounds, a A15-type Frank–Kasper phase is formed upon side-chain elongation in the steric frustration range at the transition from the triangular to the much larger square honeycombs. In contrast to the previously known tetrahedral sphere packings the A15 phase is in this case formed by tetrahedral networks of aggregates of parallelly organized π-conjugated rods. This allows the design of compounds with wide ranges of the A15 network down to room temperature. However, its formation becomes strongly disfavored by core fluorination that is attributed to a changing mode of core–core interaction that also modifies the square honeycombs by deformation of the squares into rectangular or rhombic cells, either with or without emergence of tilt of the rods
Divergence in physical, chemical, and biological soil properties caused by different long-term bare fallow management and natural succession
No full textThe absence of plants has profound effects on many ecosystem functions of soil. Long-term bare fallow trials are valuable tools for studying the dynamics in soil carbon decline and associated soil degradation. However, it is challenging to disentangle the contribution of missing organic inputs from the frequent physical disturbance caused by soil tillage or herbicide application to keep the soil free from vegetation.
In this study, we evaluate a unique long-term experiment (36 years) in which a bare fallow was established using different methods: i) mechanically through soil tillage, ii) chemically with herbicides, and iii) a combination of both methods. The aim was to separately assess the effects of tillage and herbicide application on various soil properties. Additionally, the bare fallow treatments were compared with natural succession to evaluate the effect of missing organic inputs. We monitored the annual dynamics of carbon and nitrogen contents in the topsoil (0–30 cm) and subsoil (30–60 cm). In addition, we analyzed the shallow topsoil (5–10 cm) comprehensively by integrating physical properties (microstructure and hydraulic properties), chemical properties and biological properties.
All bare fallows were declining in carbon contents at very similar rates while physical disturbance by conventional tillage did not accelerate this effect. In both soil depths of all bare fallows a fast decline in C content during the first ten years was followed by a more gradual or no decline. A large share of the long-term stable carbon was contributed by pyrogenic carbon and to a lesser degree by microbially processed carbon. In the natural succession, the annual increase in soil organic carbon contents was more pronounced in the topsoil than in the subsoil and had not reached a plateau after 36 years.
Irrespective of the bare fallow treatment, the absence of plants ceased the nutrient uplift by roots and the supply of carbon, which drastically reduced all indicators of biological activity like basal respiration, mesofauna abundance, and feeding activity. Soil tillage had a greater impact on the diversity of soil organisms than the application of herbicides. This was due to the disturbance of soil structure, the resulting changes in physical soil properties and the structure of habitats. In addition, tillage effects were stronger for fungal than bacterial communities, as fungal hyphae might be more susceptible to physical disturbance. The bioporosity and especially the amount of empty root channels was elevated in the herbicide fallow to values in the same range as the natural succession, despite the sparse vegetation cover. The fragmentation of the soil matrix by plowing drastically decreased the unsaturated hydraulic conductivity without affecting water retention.
In summary, the frequent physical disturbance by soil tillage had a surprisingly small effect on the quantity and quality of organic carbon, as the decline and shifts in molecular composition were dominated by the absence of organic inputs. In turn, strong effects of physical disturbance were observed for soil properties that depend on pore structure and its persistence in time, like hydraulic conductivity and microbial communities
Patterns of intraspecific and intraindividual trait variation in trees along experimental diversity gradients
No full textPhenotypic differences addressed from functional traits are widely used to study forest functioning. However, while ecological studies have traditionally focused on species-level trait differences, recent research emphasizes the need of considering intraspecific and intraindividual trait variation. Using leaf-level data collected in two large-scale forest biodiversity experiments in subtropical China and in Germany, I studied leaf trait variation along diversity gradients. The results show that trees change their leaf strategy and the leaf variability within the crown in response to diversity. Further, intraspecific trait variation is higher in monocultures to alleviate intraspecific competitive interactions and decreases with increasing tree species richness. Last, the results show how the organization of intraspecific and intraindividual trait variation lead to higher functional diversity of forest stands, which highlights their importance for understanding forest functioning