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Techniques like speckle holography and shearography are rarely applied due to the complexity of instrument setup and lack of automated result analysis, despite their potential. By simulating speckle interferometric outcomes, we seek to address these challenges, enabling more efficient measurement processes and paving the way for automated defect recognition. This research focuses on developing a simulation code for speckle interferometric results derived from finite element analyses. The aim is to improve the parameter settings of speckle interferometry measurements and create specific datasets, which will be used to develop machine learning-based methods for automation in series production.
Cellular adhesion and contractility are essential for cell movement. In this study, we investigated the effects of actin stabilization on adhesion properties, contractility, and cell migration. For this, we used the recently synthesized actin stabilizer miuraenamide A (MiuA), which has been discussed as a more reliable alternative to the otherwise commonly used actin stabilizer jasplakinolide. We investigated the number and size of focal adhesions in RPE-1 cells and used single-cell force spectroscopy to evaluate the adhesion properties of those cells after MiuA treatment. We showed that MiuA increases the number of focal adhesions while decreasing their size and reduces adhesion energy and force. Additionally, we investigated its effects on the contractility of RPE-1 cells by measuring their contractile energy using pattern-based contractility screening (PaCS). We found no significant change in contractility after MiuA treatment. Finally, we confined RPE-1 cells in PDMS microchannels and analyzed their migration after treatment with MiuA, showing that neither their speed nor their persistence is affected by MiuA. To check that these effects are not specific to RPE-1 cells, we also analyzed the effects of MiuA treatment in MEF cells and neutrophils. Both MEF cells and neutrophils showed the same results as the RPE-1 cells. Our measurements indicate that, although altering focal adhesions significantly reduces adhesion, it does not impact cell contractility. This finding also clarifies why amoeboid migration, which operates independently of adhesion, remains unaffected. Additionally, it explains the previously observed reduction in mesenchymal migration, which relies on adhesion-based mechanisms.
Background: Electrical stimulation is an effective treatment method for improving motor function after stroke, but the optimal current type for patients with stroke and arm paresis remains unclear.
Objective: To compare the effects of kilohertz frequency with low-frequency current on stimulation efficiency, electrically induced force, discomfort, and muscle fatigue in patients with stroke.
Design: A randomized crossover study.
Setting: Neurological inpatient rehabilitation clinic in Germany.
Participants: A total of 23 patients with arm paresis after stroke within the last 6 months were recruited, 21 were enrolled, and 20 completed the study (7 females; mean ± SD: 66 ± 12 years; 176 ± 11 cm; 90 ± 19 kg; 57 ± 34 days since stroke).
Intervention: All patients underwent both kilohertz and low-frequency stimulation in a randomized order on 2 days (48-hour washout). Each day included a step protocol with a gradual increase in stimulation intensity, starting at the first measurable force (up to 12 steps, 1 mA increments, 8 seconds stimulation, 60 second rest) and a fatigue protocol (30 repetitions, 8 second stimulation, 3 second rest).
Main Outcome Measure: Primary outcome was stimulation efficiency (electrically induced force/stimulation intensity) [N/mA], measured during each step of the stepwise increase in current intensity protocol.
Results: Linear-mixed-effects models showed significantly higher stimulation efficiency for low-frequency stimulation (mean difference 0.14 [95% confidence interval, 0.01–0.27 N/mA], p = .031). However, current type did not significantly affect electrically induced force, level of discomfort, or muscle fatigue (p > .05).
Conclusion: The findings suggest that low-frequency stimulation is more efficient than kilohertz-frequency stimulation. However, both current types yield similar effects on force, discomfort, and fatigue, making them both viable options for wrist extensor stimulation in patients after stroke. Considering the variability among individuals, customizing the current type based on electrically induced force and perceived discomfort may enhance therapeutic outcomes. Further research on the long-term treatment effects of both current types is warranted.
A Two-Layer HiMPC Planning Framework for High-Renewable Grids: Zero-Exchange Test on Germany 2045
(2025)
High-renewables grids are planned in min but judged in milliseconds; credible studies must therefore resolve both horizons within a single model. Current adequacy tools bypass fast frequency dynamics, while detailed simulators lack multi-hour optimization, leaving investors without a unified basis for sizing storage, shifting demand, or upgrading transfers. We present a two-layer Hierarchical Model Predictive Control framework that links 15-min scheduling with 1-s corrective action and apply it to Germany’s four TSO zones under a stringent zero-exchange stress test derived from the NEP 2045 baseline. Batteries, vehicle-to-grid, pumped hydro and power-to-gas technologies are captured through aggregators; a decentralized optimizer pre-positions them, while a fast layer refines setpoints as forecasts drift; all are subject to inter-zonal transfer limits. Year-long simulations hold frequency within ±2 mHz for 99.9% of hours and below ±10 mHz during the worst multi-day renewable lull. Batteries absorb sub-second transients, electrolyzers smooth surpluses, and hydrogen turbines bridge week-long deficits — none of which violate transfer constraints. Because the algebraic core is modular, analysts can insert new asset classes or policy rules with minimal code change, enabling policy-relevant scenario studies from storage mandates to capacity-upgrade plans. The work elevates predictive control from plant-scale demonstrations to system-level planning practice. It unifies adequacy sizing and dynamic-performance evaluation in a single optimization loop, delivering an open, scalable blueprint for high-renewables assessments. The framework is readily portable to other interconnected grids, supporting analyses of storage obligations, hydrogen roll-outs and islanding strategies.
Due to a lack of investigated materials for the additive manufacturing of multi-use functional parts in bioprocess engineering, this study aimed to evaluate the influence of multiple autoclaving cycles on the properties of a heat-resistant material (xPeek147) printed with vat photopolymerization. Sample bodies were tested regarding their mechanical properties of tensile strength, elongation at break, and Charpy impact, as well as surface properties of roughness and wettability after up to 50 autoclaving cycles (121 °C, 2 bars, 15 min). The tightness was checked after up to 20 cycles, and accuracy was inspected for manufactured benchmark bodies after up to 10 autoclaving cycles. The reported results showed no significant changes in tensile strength, elongation at break and Charpy impact after 20 cycles, but a significant decrease after 50 autoclaving cycles, accompanied by microcracks in the structure. Regarding the surface properties the material retained its hydrophilicity, and the surface roughness was not affected significantly. No changes in tightness occurred, and the benchmark bodies for dimensional changes showed no process-relevant deviations. Through the investigations, a material for the additive manufacturing of multi-use functional parts for bioprocess engineering was identified. Additionally, a testing method for materials with the same intended application was provided.
Background: Backpacks are essential in the daily lives of children. Carrying a heavy backpack affects trunk posture during standing. It remains unclear, whether this effect is also observed during gait.
Research question: How do different backpack weights affect trunk kinematics during walking in children?
Methods: Sixteen children stood and walked on a 5 m walkway with a custom load-carrying-system simulating unloaded and loaded backpacks (10 %;20 %;30 % of body mass (BM). A marker-based 3D motion analysis system captured whole-body kinematics (Rizzoli model). During walking, the primary outcomes were the maximum ranges of motion (RoM;[°]) of thoracic and lumbar trunk segmental angles in three planes. During standing, the average angles over 5 s were measured in three planes. Secondary measures included stride length, stride time, and velocity during walking. The children's own backpacks' weights were measured and expressed as a percentage of body mass. Statistical analysis was performed using repeated-measures ANOVA (α=0.05) and Tukey-Kramer post hoc test.
Results: The average weight of the children’s own backpack was 15.4 ± 7.4 %BM. For the experimental conditions, the average weights added to the load-carrying system were 3.3 ± 0.8 kg (10 %BM), 6.5 ± 1.7 kg (20 %BM), and 9.8 ± 2.5 kg (30 %BM). During standing, the average trunk flexion angles (sagittal plane) of the lumbar trunk segment significantly increased with increased backpack weight (p = 0.002). During walking, no changes in sagittal plane RoM but significant decreases in lumbar and thoracic transversal and frontal plane RoM (p < 0.001), stride length (p = 0.047) and velocity (p = 0.041) were observed with additional weight. No significant differences were observed for stride time between the conditions.
Significance: Added backpack weight led to a more flexed trunk posture during standing and reduced transversal and frontal plane trunk movement, stride length, and gait velocity during walking. These adjustments likely compensate for the dorsally displaced center of mass and minimize energy expenditure by reducing trunk-backpack-angular momentum during walking.
This study investigates the effects of mechanical strain on the surface roughness of copper conductors, focusing on the electrolyte-refined copper (Cu-ETP, CW004A) used in H07V-U 1.5 mm2 single-core cables. For the first time, the surface roughness evolution is characterized using the power spectral density (PSD) function, enabling a detailed roughness analysis across different spatial length scales. Conductors were subjected to mechanical stress, with measurements taken at multiple stages of service life. The study confirms the results from other studies that surface roughness increases significantly in the early stages of loading, with a plateau observed in 50 % - 75 % of cycles to failure. Micro crack formation and material extrusion are identified as key mechanisms driving roughness growth, especially at small length scales, with a shift towards larger length scales as strain intensifies. The increasing Hurst exponent suggests a transformation from a random to a more persistent and correlated surface. The results underscore the potential of power spectral density analysis in understanding surface behavior in copper conductors.
Blue and green spaces in cities provide essential ecosystem services to their inhabitants, including recreational and experiential opportunities. Their importance became further highlighted during the COVID-19 pandemic as urbanites sought to relieve some of the associated pressure. However, urban ecosystems are threatened by degradation and pollution, but also by other activities, including recreation. In this context, protected areas face the challenge of balancing visitor interests with conservation objectives, particularly in peri-urban areas. Social media provides an opportunity to analyse human activities in such areas. This study investigates spatial and temporal patterns in Instagram photos at three case study sites in Vienna, Lainzer Tiergarten, Lobau, and Nussberg with different protection statuses between 2018 and 2022. Automated content labeling using Google's Cloud Vision API and subsequent classification identified 19 clusters from 54,751 downloaded photos. Seasonal variations were observed, such as the prevalence of Plant and Insect photos in spring and summer, and Landscape content in autumn and winter. The COVID-19 pandemic coincided with and contributed to an increase in user activity, but seasonal trends were unaffected. Site-specific patterns also emerged, with Panoramas dominating in Nussberg, the Riverscape characterizing Lobau, and Woodlands dominating in Lainzer Tiergarten. Our findings demonstrate that automated social media photo content analysis can capture spatial and temporal variations in visitor behavior and landscape preferences, providing valuable insights for targeted visitor management and the establishment of conservation strategies in peri-urban ecosystems. Integrating these analyses with other methods, such as surveys or mobile phone tracking, can provide a more comprehensive understanding of human-environment interactions.
Applying the Cultural Values Model to assess biocultural change in Eastern European wood-pastures
(2025)
1. Traditional wood-pastures are emblematic of multifunctional farming systems. Despite their exceptional ecological and cultural value, these systems are undergoing rapid transformation under the combined pressures of modernization, land-use intensification and shifting societal values.
2. We apply the Stephenson's Cultural Values Model to assess the biocultural complexity of 110 ancient wood-pastures across Transylvania, Romania, a unique region of Eastern Europe, where traditional land-use systems persist amidst accelerating institutional and economic change. The three dimensions of the Cultural Values Model—‘Forms’ (material structures), ‘Practices’ (land-use activities) and ‘Relationships’ (cultural meanings and memories)—were quantified through field surveys and 32 semi-structured interviews with local stakeholders.
3. Our results reveal diverse biocultural profiles, with traditional and modern elements (i.e. ‘Forms’ and ‘Practices’) frequently co-occurring. While many sites retain legacy features such as scattered veteran trees and extensive grazing, signs of social-ecological reconfiguration are evident, including electric fencing, mechanized infrastructure, and declining communal governance. Landscape-level analyses show that traditional features (‘Forms’, ‘Practices’ in the Cultural Values Model framework) persist more often in rugged terrains, whereas modernization predominates in flatter, more accessible areas. Interview data show an erosion of cultural engagement, stewardship norms and local agency.
4. Our findings suggest that the transformation of ancient wood-pastures can be effectively traced through the three pillars of the Cultural Values Model: ‘Forms’, ‘Practices’ and ‘Relationships’. The framework proved especially valuable in disentangling how material, functional and symbolic dimensions of these landscapes evolve in response to socio-economic and institutional pressures. We also showed that the Cultural Values Model can be a practical tool for assessing biocultural complexity and identifying early signs of system reconfiguration of traditional farming systems.
In acute stroke patients, arithmetic fact retrieval deficits have been observed due to disrupted white matter connections within a left-hemispheric network centered around the angular gyrus and middle temporal gyrus (Smaczny et al., 2023). However, it remains unclear which specific structural disconnections also hinder successful remediation in the chronic stage of stroke. In this study, 92 patients were examined to determine which impairments continue to affect multiplication performance even in the chronic phase after a first-time unilateral left-hemispheric stroke. Our results revealed a strong association between impaired multiplication performance and the disconnection of left long-term memory (para)hippocampal areas from left frontal and right parietal regions. Thus, unlike previous findings in the acute stroke phase, our results in the chronic phase emphasize the importance of (para)hippocampal regions for successful multiplication performance. We suggest that the affected areas and connections in chronic patients with persistent multiplication problems not only indicate areas that are crucial for the relearning of arithmetic facts, but also those crucial for the learning of arithmetic facts in general. More generally, we suggest that the acquisition of arithmetic facts depends on structural integrity of a network centered around the left (para)hippocampus, while the retrieval of consolidated arithmetic facts from memory relies on the integrity of a left-hemispheric network involving angular gyrus and middle temporal gyrus.
