Willkommen bei JLUpub
JLUpub ist das institutionelle Repositorium der Justus-Liebig-Universität.
JLUpub bietet Mitgliedern und Angehörigen der Universität die Möglichkeit neben wissenschaftlichen Dokumenten auch Forschungsdaten elektronisch zu veröffentlichen und dauerhaft zugänglich zu machen. Alle Veröffentlichungen erhalten einen Digital Object Identifier (DOI) und werden über nationale und internationale Bibliothekskataloge sowie Suchmaschinen nachgewiesen und auffindbar.
Neue Veröffentlichungen:
Item type: Item , Deep Learning–Based Data-Driven Analysis of Complex Plasmas in a Direct Current Discharge(2026) Dormagen, Niklas JosephComplex plasmas, which are composed of electrons, ions, neutral gas atoms and micrometer sized particles, provide a unique platform for studying fundamental physical phenomena. Because the interparticle distances are comparatively large, it is possible to resolve individual particles optically. This makes it possible to investigate processes such as crystallisation, phase transitions and collective excitations. One of the experimental platforms for studying complex plasmas is the Plasma Crystal Experiment 4 (PK-4), which operates under direct current (DC) conditions. It is used on Earth and in microgravity environments, like on the International Space Station (ISS) and during parabolic flights. To reach the full potential of complex plasmas, however, robust methods must be developed to detect, track, and classify microscopic particles. Traditional image processing techniques often reach their limits in this context, especially for large datasets or under experimentally induced image noise. Therefore, modern machine learning approaches and deep neural networks offer a promising way to optimize and automate the analysis of complex plasmas, where possible.<br><br> This dissertation presents a comprehensive framework for using deep learning Methods to analyze complex plasmas in the PK-4 experiment. The work is organized into three main contributions. First, a compact U-Net architecture is developed for efficient and accurate particle detection and tracking in dense plasmas. Second, WignerNet, a PointNet based model, is introduced to enable the local classification of crystalline domains using three-dimensional, Voronoi-based representations. Third, an extended graph neural network approach is used to identify more complex structures. Combining these methods greatly improves the diagnosis of complex plasmas by enabling scalable analysis at the single-particle level. In this way, the dissertation contributes both methodologically and experimentally to a deeper understanding of the dynamics and self-organization of complex plasma systems.Item type: Item , Dynamic Capacity Allocation in Motor-Cognitive Dual-Tasking - probed by Semantic Auditory Stimuli(2025) Müller, JelenaHuman performance in multitasking situations is constrained by limited processing capacity, requiring dynamic allocation of cognitive and motor resources across simultaneously executed tasks. The present work investigates adaptive capacity allocation during motor-cognitive dual- and triple-task performance using semantically loaded auditory probe stimuli. Building on classical capacity theories, multiple resource models, and structural bottleneck approaches, a two-dimensional time-regime model is proposed that integrates both temporal processing demands and accuracy-related resource allocation. <br> Across a series of experiments, participants performed combinations of a continuous motor tracking task, a cognitive calculation task, and an auditory reaction time task under varying task-load conditions. Performance was assessed using reaction time and error, calculation time and error, motor time lag, and motor accuracy measures. In addition, semantically meaningful auditory stimuli were introduced to examine content-specific interference effects on ongoing task performance. Event-related analyses further differentiated interference patterns across distinct temporal regions of interest before, during, and after stimulus processing. <br> Results consistently demonstrated performance decrements during multitasking compared to single-task conditions, particularly reflected in prolonged reaction times, increased motor delays, and reduced motor precision. However, error rates often remained comparatively stable, suggesting adaptive redistribution of processing capacity to preserve task accuracy. Semantic stimuli affected reaction times and cognitive processing, while motor performance showed both interference and compensatory stabilization effects depending on task demands and processing phase. Event-related analyses revealed that performance impairments were temporally dynamic rather than constant, supporting the assumption of flexible resource allocation across task phases. <br> The findings support the proposed time-regime model, according to which tasks operating under flexible temporal constraints are prolonged to maintain accuracy, whereas tasks with fixed temporal requirements are more susceptible to interference and performance breakdown. The findings contribute to a deeper understanding of cognitive-motor interference mechanisms and offer a framework for investigating real-world multitasking behavior in domains such as driving, sports, rehabilitation, and human-machine interaction.Item type: Item , Machbarkeit für ein nachhaltiges Ernährungsnetzwerk in Stadt und Landkreis Kassel – Abschlussbericht BioRegion Kassel Stadt + Land(2025-12) Herzig, Christian; Keller, Martina; Bruse, Maike; Tolle, Nils; Flörke, Silke; Ross, Stefanie; Büning, Lena; Herrlich, Lara; Nutz, Katharina(IBAE Bericht; 2025, Dezember)Das Projekt „BioRegion Kassel – Stadt und Land: Aufbau und Stärkung bioregionaler Wertschöpfungsketten vom Acker auf den Teller" untersuchte die Voraussetzungen für eine Versorgung der Gemeinschaftsverpflegung (GV) mit ökologischen Lebensmitteln aus der Region Kassel/Nordhessen. Projektpartner waren das Institut für Betriebslehre der Agrar- und Ernährungswirtschaft (IBAE) der Justus-Liebig-Universität Gießen, das ZÖL e.V. als Träger der Ökomodellregion Nordhessen sowie der GV-Praxispartner Ganz+Gar. In einem transdisziplinären Mixed-Methods-Ansatz wurden mittels Akteursmapping, Interviews und Workshops Hemmnisse und Potenziale entlang von Wertschöpfungsketten (WSK) identifiziert. Eine Foodshed-Analyse ermittelte die regionale Eigenversorgungskapazität u. a. für Getreide, Eier und Kartoffeln. Da die aktuelle Nachfrage kein neues physisches Bündelzentrum trägt, richtete sich der Fokus des Forschungs- und Entwicklungsprojekts auf den Ausbau und die Stärkung bestehender Bündel- und Logistikstrukturen. Hierfür wurden als zentrale Ergebnisse drei praxistaugliche Funktionsmodelle zur Warenbündelung entwickelt sowie Schlüsselfaktoren – insbesondere fehlende Verarbeitungsinfrastrukturen und instabile Nachfrage – identifiziert. Die Ergebnisse bieten eine fundierte Entscheidungsgrundlage für Kommunalpolitik und WSK-Akteur*innen in der Projektkulisse Kassel - Stadt und Landkreis.Item type: Item , IRG1/Itaconate Axis as an Immunometabolic Regulator of Pulmonary Hypertension(2024) Hesami, GolnazPulmonary hypertension (PH) is a progressive cardiopulmonary disease characterized by pulmonary vascular remodeling and right ventricular hypertrophy, with immune cell–mediated mechanisms playing a central role. Immune-Responsive Gene 1 (IRG1), which encodes the enzyme responsible for itaconate production in macrophages, has established functions in inflammatory metabolism; however, its role in cardiopulmonary homeostasis and PH remains unclear. In this study, we identify the IRG1/itaconate axis as a regulator of inter-organ communication between the bone marrow (BM), heart, and lung. Using IRG1-deficient (Irg1⁻/⁻) mice, we demonstrate that loss of Irg1 leads to cardiopulmonary alterations driven by immune and metabolic dysregulation. Cardiac phenotyping of Irg1⁻/⁻ mice revealed significant right and left ventricular hypertrophy and dysfunction, accompanied by increased macrophage and dendritic cell infiltration. Transcriptomic analysis showed activation of inflammatory pathways, including TNF-α/NF-κB signaling, hypoxia-associated responses, and upregulation of endothelin-related genes. Epigenetic alterations were also observed, with increased expression of the histone demethylase Jmjd3 and reduced H3K27me3 levels, suggesting a mechanism linking IRG1 deficiency to sustained inflammation and cardiac remodeling. In the lung, Irg1 deficiency predisposed to pulmonary vascular remodeling and heightened susceptibility to hypoxia-induced PH, associated with an expanded myeloid compartment and enhanced inflammatory signaling. These findings are consistent with observations in PAH patients, who exhibit increased myeloid cell populations compared to non-PH controls. Adoptive transfer of BM from Irg1⁻/⁻ mice into irradiated WT mice induced cardiac hypertrophy, highlighting the strong contribution of BM to cardiac dysfunction under Irg1 deficiency. Additionally, IRG1-deficient macrophages induced hypertrophic and fibrotic responses in cardiac fibroblasts via paracrine signaling. IRG1 deficiency disrupted hematopoietic stem progenitor cell (HSPC) function and differentiation. This was associated with impaired purine metabolism, increased ATP levels, and activation of the NLRP3 inflammasome, leading to enhanced inflammatory signaling and immune cell mobilization into peripheral organs, particularly the heart and lung. Collectively, these findings indicate that IRG1/itaconate axis deficiency drives the cardiopulmonary phenotype by dysregulating HSPC differentiation and mobilization through immunometabolic alterations, ultimately leading to pulmonary vascular remodeling and cardiac hypertrophy, highlighting its potential as a therapeutic target for PH and related cardiopulmonary complications.Item type: Item , Glutaredoxin 5 as a novel target for β cell survival and regeneration(2025) Zhou, MengmengDiabetes mellitus is a chronic metabolic disorder characterized by progressive pancreatic β cell dysfunction and insulin resistance, ultimately leading to persistent hyperglycemia and severe systemic complications. Increasing evidence suggests that mitochondrial dysfunction, iron imbalance, and lipid overload contribute to β cell failure. Glutaredoxin 5 (Grx5), a mitochondrial protein involved in iron-sulfur cluster biogenesis, plays an important role in cellular iron homeostasis. However, its function in pancreatic β cells under lipotoxic conditions remains unclear. This thesis investigated the role of Grx5 in β cell survival and function, focusing on its interaction with free fatty acids and iron metabolism. In vitro experiments were performed using mouse MIN6 cells and human EndoC-βH3 cells. Cells were exposed to oleic acid or treated with ferroptosis modulators, and metabolic activity, insulin secretion, lipid peroxidation, and iron homeostasis were analyzed. In addition, Grx5 expression was knocked down by siRNA to assess its functional role in β cells. In vivo, β-cell-specific Grx5-overexpressing mice were subjected to a high-fat diet to evaluate glucose metabolism. Furthermore, EndoC-βH3-derived pseudoislets were transplanted into streptozotocin-induced diabetic mice to assess their therapeutic potential. The results showed that oleic acid treatment in β cells led to reduced metabolic activity, insulin content, and secretion, accompanied by increased mitochondrial iron accumulation and decreased levels of Grx5 and Gpx4. In addition, the ferroptosis inducer ML-162 reduced insulin content and secretion, Grx5 levels, and increased lipid peroxidation and mitochondrial free iron accumulation. Cell metabolic activity was only reduced in the presence of oleic acid, and the reduction of Gpx4 and mitochondrial iron accumulation was more evident in the presence of oleic acid. Notably, the ferroptosis inhibitor Liproxstatin-1 was able to alleviate the oleic acid-induced reduction in insulin and Grx5 levels, as well as the associated lipid peroxidation and mitochondrial free iron overload. This suggests that exposure to oleic acid increases susceptibility to ferroptosis, an iron-dependent form of cell death characterized by lipid peroxidation. Grx5 knockdown resulted in reduced insulin content and secretion, increased lipid peroxidation, and mitochondrial free iron overload. This was accompanied by cytoplas mic free iron depletion and decreased cell metabolic activity. However, Grx5 overexpression in vivo did not significantly protect against high-fat diet-induced hyperglycemia, suggesting a limited systemic effect. Finally, EndoC-βH3 pseudoislets demonstrated enhanced glucose-stimulated insulin secretion and improved glycemic control after transplantation, although differences compared to native islets indicate potential functional limitations. In conclusion, we propose that exposure to oleic acid leads to decreased Grx5 levels, impairing iron metabolism, promoting lipid peroxidation, and eventually causing β cell dysfunction. However, Grx5 overexpression in vivo fails to reverse high fat diet-in duced hyperglycemia. Additionally, we highlighted the potential of pseudoislet trans plantation as a therapeutic strategy for diabetes.