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Controlling Excitons in Quasi-1D Perovskites by Dielectric Screening and Connectivity
No full textReducing the dimensionality of metal-halide perovskites enhances quantum and dielectric confinement, enabling tunable excitonic properties. In one dimension, the arrangement of metal-halide octahedra in chains with corner-, edge-, or face-sharing connectivity allows for additional structural flexibility. This not only expands material design possibilities but also reflects quasi-one-dimensional motifs that arise during perovskite formation but are poorly understood. Using first-principles many-body perturbation theory within the GW and Bethe-Salpeter equation framework, we provide a comprehensive picture of how one-dimensional confinement, octahedral connectivity and dielectric screening affect optical absorption and exciton photophysics in these materials. Our calculations reveal that increasing octahedral connectivity leads to increased exciton binding and complex, anisotropic optical signatures. However, in experimentally synthesized organic-inorganic systems, pronounced dielectric screening effects can reduce exciton binding energies by several hundred meV, altering these trends. These findings offer insights and design principles for excitonic properties, and aid the interpretation of optical experiments on one-dimensional perovskites
Towards Economic Zero Boil-Off Technology for Liquid Hydrogen Storage
No full textHydrogen is increasingly recognized as a cornerstone of the transition to sustainable energy systems. Storing hydrogen in liquefied form (LH₂) is particularly advantageous due to its relatively high energy density and scalability for storage and transport. However, managing boil-off rates (BOR) during storage and transportation remains a significant challenge. Hydrogen boil-off leads to safety concerns, environmental impacts, and economic losses, highlighting the critical need for zero boil-off (ZBO) systems. Depending on the size and application, the BOR ranges from 0.05–0.2% per day for large-scale, stationary, spherical storage tanks (>500 m³) to 0.3–1% per day for stationary cylindrical vessels (1–100 m³), and even up to 1.5% per day for 0.1 m³ tanks typically used in mobile applications.Advances in passive insulation technologies, such as vacuum-insulated multi-layer insulation (MLI) and variable density MLI (VDMLI), have shown potential to reduce BOR further compared to conventional vacuum-perlite. However, passive measures alone are insufficient due to the high liquefaction energy costs (~30% of hydrogen’s energy capacity) of LH2. This underscores the need for active cooling systems to achieve ZBO in LH₂ storage and transport applications. While existing ZBO systems in aerospace demonstrate feasibility, their high energy requirements and costs limit large-scale industrial deployment.An in-depth review of the current state of LH₂ storage technologies was conducted, focusing on BOR mitigation strategies and their limitations. A framework for the design and development of economic ZBO systems is proposed, with an emphasis on bridging the gap between laboratory-scale solutions and practical implementation. This work is part of the HyTROS program under the Dutch GroenvermogenNL initiative to advance hydrogen storage and transport technologies.<br/
Improved diagnostic accuracy for polymyalgia rheumatica using FDG-PET/CT with clinical diagnosis or 2012 ACR/ EULAR classification criteria
No full textObjective: In routine care, clinicians may employ 2-[18F]fluoro-2-deoxy-D-glucose (FDG)-PET/CT to validate their initial clinical diagnosis of PMR. Nevertheless, the diagnostic utility of combining FDG-PET/CT findings with clinical presentation has not been explored. Therefore, this study aimed to investigate whether the diagnostic accuracy for PMR could be enhanced by combining FDG-PET/CT findings with the clinical baseline diagnosis or the 2012 ACR/EULAR clinical classification criteria for PMR. Methods: An investigation and a validation cohort were included from two countries, encompassing 66/27 and 36/21 PMR/non-PMR patients, respectively. The cohorts comprised treatment-naïve patients suspected of PMR, who initially received a clinical baseline diagnosis and underwent FDG-PET/CT scans. The FDG-PET/CT Leuven score was applied to classify patients as either PMR or non-PMR and combined with the clinical baseline diagnosis. Final diagnoses were established through clinical follow-up after 12 or six months in the investigation and validation cohorts, respectively. Results: In the investigation cohort, a clinical baseline diagnosis yielded a sensitivity/specificity of 94%/82%, compared with 78%/70% using the ACR/EULAR criteria. Combining the clinical baseline diagnosis with a positive Leuven score showed a sensitivity/specificity of 80%/93%, compared with 80%/82% for an ACR/EULAR-Leuven score. In the validation cohort, the baseline diagnosis revealed a sensitivity/specificity of 100%/91%, compared with 92%/76% using the ACR/EULAR criteria. Combining FDG-PET/CT with the baseline diagnosis demonstrated a sensitivity/specificity of 83%/95% compared with 89%/81% for the ACR/EULAR-Leuven score. Conclusion: Combining FDG-PET/CT findings with the clinical baseline diagnosis or ACR/EULAR clinical classification criteria can improve the diagnostic specificity for PMR.</p
Selecting Targets for Molecular Imaging of Gastric Cancer:An Immunohistochemical Evaluation
No full textPurpose: Tumor-targeted positron emission tomography (PET) and fluorescence-guided surgery (FGS) could address current challenges in pre- and intraoperative imaging of gastric cancer. Adequate selection of molecular imaging targets remains crucial for successful tumor visualization. This study evaluated the potential of integrin αvβ6, carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), epidermal growth factor receptor (EGFR), epithelial cell adhesion molecule (EpCAM) and human epidermal growth factor receptor-2 (HER2) for molecular imaging of primary gastric cancer, as well as lymph node and distant metastases. Methods: Expression of αvβ6, CEACAM5, EGFR, EpCAM and HER2 was determined using immunohistochemistry in human tissue specimens of primary gastric adenocarcinoma, healthy surrounding stomach, esophageal and duodenal tissue, tumor-positive and tumor-negative lymph nodes, and distant metastases, followed by quantification using the total immunostaining score (TIS). Results: Positive biomarker expression in primary gastric tumors was observed in 86% for αvβ6, 72% for CEACAM5, 77% for EGFR, 93% for EpCAM and 71% for HER2. Tumor expression of CEACAM5, EGFR and EpCAM was higher compared to healthy stomach tissue expression, while this was not the case for αvβ6 and HER2. Tumor-positive lymph nodes could be distinguished from tumor-negative lymph nodes, with accuracy ranging from 82 to 93% between biomarkers. CEACAM5, EGFR and EpCAM were abundantly expressed on distant metastases, with expression in 88–95% of tissue specimens. Conclusion: Our findings show that CEACAM5, EGFR and EpCAM are promising targets for molecular imaging of primary gastric cancer, as well as visualization of both lymph node and distant metastases. Further clinical evaluation of PET and FGS tracers targeting these antigens is warranted.</p
Forecasting InSAR-derived slope movement from climate records at Baihetan reservoir
Get PDFInterferometric Synthetic Aperture Radar (InSAR) has become a powerful tool for monitoring hillslope deformation. Recent advances have focused on integrating InSAR with predictive models, yet limited effort has been dedicated to developing scenario-based prediction of hillslope deformation informed by climatological records to assess potential geomorphological hazards under future extreme weather conditions. This study investigates slope instability near the Baihetan Reservoir in China, where notable deformation followed its impoundment in 2021. Using Sentinel-1 images (2021–2024), we applied SBAS and PSI techniques to detect 78 and 65 deformation anomalies from descending and ascending orbits, respectively. A two-dimensional Temporal Convolutional Network (2D-TCN) was developed to predict deformation based on slope angle, precipitation, temperature, and reservoir level. We simulated eight extreme weather scenarios based on 40 years of historical climate data. Results show the model reliably predicts spatiotemporal deformation, with the most hazardous scenarios involving >740 mm precipitation, reservoir level rise, and temperatures >20 °C. For example, the Xiapingzi landslide showed >100 mm deformation within 60 days under one scenario. Although the model itself is not directly transferable to other regions, the framework and workflow are. This approach supports proactive hazard management by quantifying landslide responses to extreme weather, providing a valuable tool for scenario-based risk assessment.</p
Tailored Ordering and Inventory Management System for Learning Factories
No full textLearning Factories (LFs), embodied as physical environments replicating realistic production systems for education, are rapidly expanding. These LFs need to enable a variety of learning objectives, allowing diverse learning activities to leverage their capabilities whilst keeping them human-centered. Subsequently, the digital level of LFs needs to be enhanced with technology and manufacturing solutions that improve the system flexibility whilst still maintaining high levels of user-friendliness and industry-realism. Based on literature and empirical observations, communication between users in certain LFs is not efficient and, hence, lacks industry realism. Moreover, inefficient unstructured material handling led to high waste of non-value-adding time and traffic bottlenecks. To avoid the inherent complexity of existing commercial systems, an Order and Inventory Management System (OIMS) was developed in-house to enhance the workflow of manual assembly tasks, facilitate inventory management, avoid vendor lock-in, and streamline material handling by enhancing communications and information flows. To give practical ground and evaluate the efficiency and flexibility improvements of this OIMS, a case study was conducted within the FAB2. The outcomes demonstrate highly flexible material handling and streamlined inventory management capabilities, unconstrained by vendor lock-in. Additional complementary benefits were also found concerning measurable insights into the operational status of workstations.</p
Real-Time Gaze Awareness in Conversational Agents:Enhancing Collaboration and Personalization in VR Art Experiences
Get PDFThe increasing integration of conversational agents into interactive environments has prompted the investigation of methods to enhance user experience. This study explores how varying levels of real-time gaze awareness influence interactions with LLM-based conversational agents within a Virtual Reality (VR) art exhibition. Fifty-one participants were randomly assigned to one of three experimental groups, each experiencing a VR exhibition featuring five paintings and interacting with a conversational agent. The groups differed based on the agent’s gaze-awareness capabilities: 1) identifying the painting the user was viewing, 2) responding based on specific areas within a painting, and 3) analyzing detailed gaze patterns, including fixation counts, area transitions, and dwell times. Results revealed that participants in the third group, where detailed gaze pattern analysis was employed, perceived their interactions as significantly more personalized and collaborative. However, this did not lead to measurable differences in reported enjoyment, engagement, or perceived gaze awareness compared to the other conditions
Seeing and Speaking with Culture:How Visitor Profiles Shape Multimodal Interaction in a VR Art Exhibition
Get PDFUnderstanding how users engage with socially interactive agents in immersive cultural environments is crucial for designing adaptive and contextually appropriate virtual experiences. This study explores how individual user traits—including familiarity with virtual reality, museum visitation habits, prior knowledge, interest in specific artworks, and interaction preferences—relate to gaze behavior and conversational engagement in a VR art exhibition. Fifty-two participants explored a virtual museum featuring five paintings and interacted with agents designed to share information and facilitate discussion. Data were collected through questionnaires, eye-tracking metrics (e.g., fixation duration, scanpath length), and conversational transcripts (e.g., response length, number of user turns). A multimodal analysis aligned gaze and speech data to examine how visual attention and verbal interactions co-occur in relation to user traits. Results indicate that traits such as prior knowledge, interest, and personalization preferences significantly influence both gaze patterns and conversational behaviors. While some effects varied in strength or consistency, the findings offer valuable insights into how personal characteristics shape user-agent interactions. These insights inform the design of adaptive virtual agents and support broader efforts to model multimodal user bahevior for real-time personalization in immersive environment
Grenzüberschreitende Klimafolgenanpassung: Multidisziplinäre Ansätze zur Bewertung und Stärkung regionaler Dürreresilienz im Rahmen von DIWA.
No full textVector-valued Fourier hyperfunctions and boundary values
No full textThis work is dedicated to the development of the theory of Fourier hyperfunctions in one variable with values in a complex non-necessarily metrizable locally convex Hausdorff space E. Moreover, necessary and sufficient conditions are described such that a reasonable theory of E-valued Fourier hyperfunctions exists. In particular, if E is an ultrabornological PLS space, such a theory is possible if and only if E satisfies the so-called property (PA). Furthermore, many examples of such spaces having (PA) (resp. not having (PA)) are provided. We also prove that the vector-valued Fourier hyperfunctions can be realized as the sheaf generated by equivalence classes of certain compactly supported E-valued functionals and interpreted as boundary values of slowly increasing holomorphic functions