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 , Land access and feeding strategies in post-Soviet livestock husbandry: Evidence from a rangeland system in Kazakhstan(2024) Robinson, Sarah; Petrick, MartinContext: Feeding strategy is a major dimension of intensification and largely determines the environmental and economic impacts of livestock production systems, in particular concerning land use competition, greenhouse gas emissions and rural livelihoods. Literature suggests that a key driver of intensification is increasing population density – associated with decreased labor costs, shifts in demand and institutional and political change; whilst at the household level farmer education and market access are also important. However, the topic has not been addressed in the rangelands of post-Soviet Eurasia, where vast underused pasture resources may be reclaimed, but improved feeding is also a key aim of agricultural policy. Objectives: We aim to firstly describe the extent to which land users in an extensive rangeland system in Kazakhstan exploit pastures, arable land or markets to feed their animals, and secondly to explore the determinants of these decisions. Methods: We identify three potential strategies: self-production of roughage or concentrate, purchase of these inputs, or expansion of pasture use through mobile pastoralism. We then investigate the determinants of these feeding strategies and their interactions, including variables capturing farm and farmer characteristics, access to land and other assets and outcomes of post-independence reforms. We examine the factors determining the three feeding strategies using a farm survey dataset from south-eastern Kazakhstan to estimate a simultaneous equation system, considering herd size as an endogenous variable. Results and Conclusions: Herd size combined with access to land for fodder production largely determines how producers feed their livestock. Barriers to the substitution of pasture for purchased or self-produced fodder include cropland access, distance from markets, and credit availability, so that use of remote and seasonal pastures is the major feeding strategy employed by larger producers. Access to both arable land and pasture is dependent on land reform outcomes, which constrain farmers' livestock feeding decisions today. Other factors such as farmer education, human population density and household labor are less important. Significance: Grazing expansion strategies employed by farmers studied here differ from those based on external input use observed in many regions of the world. Instead, they reflect the continuing importance of pastoral resources in rangeland environments implying important trade-offs to intensification which merit further study.Item type: Item , Mid- to long-term periprosthetic bone density changes after cementless short stem hip arthroplasty in elderly: A clinical and radiological analysis(2024) Brandl, Max; Jahnke, Alexander; Fölsch, Christian; Rickert, Markus; Ishaque, Bernd AlexanderIntroduction: Short stem prostheses were originally designed for younger and more active patients. In recent years, they have been increasingly offered to older patients. This study evaluates the mid-to long-term survival of a short stem prosthesis and the changes in periprosthetic bone density following implantation of a cementless short hip stem in patients over 60 years of age. Methods: 118 patients aged over 60 received short stem prostheses. Clinical examination included Harris Hip Score (HHS) and Hip Disability and Osteoarthritis Outcome Score (HOOS). 93 patients were followed clinically for at least five years. 53 patients underwent dual-energy x-ray absorptiometry (DXA) and radiographic evaluation. Follow-up intervals were preoperative and postoperative (t0), at approximately six months (t1), at approximately two years (t2), and at approximately five years or later (t3). Results: Over a mean 6.7-year observation period for all 118 patients, one stem revision occurred due to a traumatic periprosthetic stem fracture. The five-year survival rate for the endpoint survival of the Metha® stem in 95 at-risk patients is 99.2%. HHS improved significantly from t0 55.3 ± 11.5 (range 30–79) to t3 95.3 ± 8.6 (range 57–100) at a mean of 8.0 years (p < 0.001). HOOS improved significantly in each subscale (p < 0.001). Bone mineral density (BMD) was available for review in 53 patients after a mean of 7.1 years. BMD increased from t0 to t3 in region of interest (ROI) 3 (+0.4%) and ROI 6 (+2.9%) and decreased in ROI 1 (−10.3%), ROI 2 (−9.8%), ROI 4 (−5.3%), ROI 5 (−3.4%) and ROI 7 (−23.1%). Conclusions: The evaluated short stem prosthesis shows a remarkably high survival rate in elderly patients, accompanied by excellent clinical results. Load transfer measurements show a metaphyseal-diaphyseal pattern with a trend towards increased diaphyseal transfer over the period observed.Item type: Item , Impact of earthworms on soil Si availability and wheat Si concentration in low- and high-Si soils(2024) Monoshyn, Dmytro; Chibesa, Mirriam C.; Puschenreiter, Markus; Zaller, Johann G.; Santner, JakobSilicon (Si) is a beneficial element known to increase growth and the stress resistance of plants, including resistance against drought. However, as with many other elements, only a small fraction of Si in soils is available for plant uptake. Plant-available Si originates either from the weathering of soil minerals or from the dissolution of phytoliths in plant litter. It is known that soil fauna plays a role in both processes that contribute to the availability of Si in the soil. However, very little is known about the interactions between the weathering of soil minerals and the dissolution of Si by earthworms from phytoliths and subsequent Si uptake by plants. In greenhouse pot experiments, this study investigated the effect of an epigeic earthworm species (Dendrobaena veneta) on Si availability and uptake by wheat (Triticum aestivum) grown in soils with high or low Si availability. In addition, Si-rich plant litter (wheat straw) was added to the topsoil in some treatments. The addition of plant litter significantly increased the available Si in the soil. Plant litter addition was positively correlated with the Si concentration in wheat in low-Si soil, but not in high-Si soil. Earthworms increased Si availability in soil and casts of the low-Si soil and partly of the high-Si soil, but not Si uptake by wheat. These results suggest that earthworms play an important role in regulating the Si status of soils and may influence Si uptake by plants, especially in soils with initially low Si content and when earthworm population densities are high.Item type: Item , Impedance spectroscopy using microscopic reference electrodes to analyze different rate-determining steps in aqueous dye-sensitized solar cells using nitroxide radicals as redox mediators(2024) Holzhacker, Daniel; Ringleb, Andreas; Schlettwein, DerckFor new components in dye-sensitized solar cells (DSSCs), identification and quantification of rate-limiting steps is needed to evaluate their applicability. This is particularly important if fundamental changes are studied. In this work, the use of a micro-reference electrode in DSSCs is proposed to increase the significance of electrochemical impedance spectroscopy. The recombination of charge carriers at the photoanode and the regeneration of redox mediators at the counter electrode, which typically occur on similar timescales, could be studied separately but simultaneously in cells under operating conditions. This is particularly useful in the study of water-based DSSCs. Here, cells with 2,2,6,6-Tetramethylpiperidinoxyl (TEMPO) or 4-Hydroxy-TEMPO (OH-TEMPO) as redox mediators using additives like 1-Methylbenzimidazole (MBI) are discussed. It was revealed that the charge transfer resistance (RCE) for the reduction of the oxidized redox mediator at the counter electrode (CE) limits the fill factor (FF) of such DSSCs. TEMPO/MBI electrolytes yielded low RCE and high FF, whereas OH-TEMPO in otherwise identical cells resulted in large RCE, low FF, and low conversion efficiencies. This indicates that the interface between the CE and the electrolyte significantly influences the DSSC performance of these cells and strongly depends on the electrolyte composition. Important optimization strategies could be discussed based on the present results.Item type: Item , Interphase Growth Kinetics and the Partial Electronic Conductivity of Constituents in Sulfide Solid-State Batteries(2025-06) Alt, Christoph DanielLarge-scale electrification of transportation and advancements in energy storage are key to achieving net-zero emissions. Solid-state batteries present a promising energy storage solution, expected to enable the use of high-capacity electrode materials such as lithium metal and lithium alloys, while also improving safety. However, effectively integrating high-capacity electrode materials remains a key challenge in unlocking the potential of solid-state batteries. The high reactivity of lithium metal poses both safety and operational challenges, leading to dendrite formation and loss of active redox species (i.e., long-term capacity fading). Since most inorganic solid electrolytes undergo reduction upon contact with alkali metal, the corresponding interphase formation and the resulting long-term increase in cell resistance are often underestimated. However, interphase kinetics and the consequent impact on cell performance strongly depend on the composition and properties of the reaction products. Revealing the interphase composition, growth kinetics, and the influence and role of its individual constitu-ents is crucial for developing protective strategies and enhancing material compatibility. Within this doctoral thesis, the intrinsic transport properties and growth kinetics of the interphase and its constituents for lithiated Li6PS5Cl are investigated, emphasizing their impact on long-term cell operation. Following the quantification of the interphase's partial conductivities through bulk-material synthesis, which revealed a significant resistance contribution over the battery's lifespan, conventional physiochemical concepts were revisited. The Wagner diffusion model, predicting diffusion-controlled interphase growth based on experimental data, was analyzed for solid|solid interfaces alongside the Hebb-Wagner method for accurately quantifying low electronic conductivities in lithium-ion conductors. The former addressed the influence of different interface morphologies on evaluating interphase rate constants by impedance measurements, while the latter revealed the partial electronic conductivity of lithium halides (i.e., LiCl, LiBr, and LiI) present in various interphases. Alloy electrodes, owing to their higher electrode potentials relative to lithium metal, are expected to cause reduced degradation of sulfide solid electrolytes. In this context, In/(InLi)x electrodes – prominent for exhibiting a stable potential of 0.62 V vs. Li+/Li – were first investigated to assess how preparation influences electrode microstructure and performance. Controlling microstructure is critical to avoid current constriction and ensure consistent operation. Studies on thin indium films deposited on current collectors offered insights into interphase growth kinetics at alloying interlayers – an essential challenge for reservoir-free cells – and highlighted the gradual degradation of Li6PS5Cl at the electrode potential of In/(InLi)x. Overall, this doctoral thesis advances the fundamental understanding of intrinsic degradation processes at the electrode|electrolyte interface. In particular, this work provides a new perspective on how multiphase interphases form and evolve over time, depending on their partial ionic and electronic transport properties. It delivers essential insights on previously inaccessible kinetic parameters that now enable more accurate computational simulations, improve the prediction by analytical models, and guide the rational design of more stable materials and interfaces to minimize capacity losses in (reservoir-free) solid-state batteries.