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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:
Influence of the First and Second Coordination Sphere on the Stability and Reactivity of Copper(I) Complexes with Dioxygen
(2025) Granichny, Alexander
Selective oxidation reactions are of crucial importance to the chemical industry. However, many current methods are not sustainable, often relying on expensive noble metal catalysts, toxic oxidants, and harsh reaction conditions. In contrast, nature demonstrates the possibility of conducting these reactions using copper proteins and dioxygen as the oxidant under mild conditions. Inspired by the functionality of copper proteins, this work focuses on the synthesis of bioinspired copper model complexes and investigates the influence of the first and second coordination sphere on the stability and reactivity with dioxygen.
Genomic and transcriptomic analyses for markers, genes and regions associated with liver copper concentration in sheep
(2024) Adeniyi, Olusegun Olaniyi
The continuous economic and health impact of copper (Cu) intoxication and deficiency in sheep farming necessitates the need to understand the influence of the ovine genome on within- and between-breed differences in liver Cu concentration in sheep. In our studies, within-breed variations in liver Cu concentration observed in flocks under similar dietary and environmental conditions ranged from 30% to 55%. The heritability estimate and accuracy (0.67 ± 0.29) observed in our study was similar to values of 0.60± 0.32 found in previous studies. Therefore, it can be concluded that this trait is most likely heritable, and it is influenced by genetic factors. To this end, we tested the probability that certain SNP markers of the ovine genome may be associated with variability in liver Cu concentration in sheep using single- and multi-locus GWAS methods. The results revealed that a total of 13 markers, identified using ML-GWAS, were associated with variability in liver Cu concentration in Merinoland sheep. Functional enrichment analysis revealed enriched GO terms such as lysosomal membrane and mitochondrial inner membrane.
To support this finding, a comparative transcriptome analysis between liver samples of Polish Merino sheep with low and high hepatic Cu concentration was performed. Among the differentially expressed genes was the SPATC1L gene, which is located 148.7 Kb from a SNP (rs427314005) identified by GWAS before. Enriched GO and KEGG pathway terms including cholesterol and retinoic acid syntheses were identified.
Furthermore, we performed selection signature analysis to identify genomic regions under selection between Cu-susceptible and Cu-tolerant sheep breeds. Findings from this study showed that regions on OAR 4, 8 and 11 are under selection for this trait. In addition, lipoxygenase and ferroptosis pathways were identified among others as enriched GO and KEGG pathway terms.
The results of the present work point to a polygenic nature of within- and between-sheep breed differences in liver Cu concentration. Additionally, our different studies suggest that pathways responsible for within-breed variation of liver Cu concentration sheep differ from those affecting between-breed variation of this trait. Further studies need to be conducted to confirm identified regions, genes or markers associated with variability in liver Cu concentration and their potential use in animal breeding.
How to reduce weaning and separation stress in dairy cow-calf contact systems? A comparison of a gradual process with the two-step nose flap method and an evaluation of different stress indicators
(2024) Vogt, Anina
Early separation of dairy cows and their calves shortly after birth is increasingly questioned by society, scientists and some farmers. Cow-calf contact (CCC) systems, which allow extended contact between a calf and their dam or a foster cow, are an alternative to this practice with many benefits for the animals’ welfare, but the weaning and separation process remains a major challenge in CCC systems. The aim of this thesis was therefore to compare the behavioral and physiological stress responses of dairy cows and their 3-months-old calves during weaning and separation either via two-step weaning using nose flaps (NF, 2 wks full-time contact while calves wore nose flaps, 1 wk fence-line contact before total separation) or via a gradual reduction of cow-calf contact time (GR, 1 wk half day contact, 1 wk morning contact, 1 wk fence-line contact before total separation, n=18 cow-calf pairs per method). As a secondary aim different indicators for weaning and separation stress were evaluated.
The behavioural responses of 36 cow-cow pairs were directly observed in the cow area and via video monitoring in the calf area, which also included the selection gate where calves could switch between areas. Locomotor play levels and lying times of calves, as well as lying and rumination time of cows, were automatically recorded with sensors. Blood and fecal samples were collected for analysis of fecal cortisol metabolite concentrations, relative telomere length and immune responses. Milk yield was continuously recorded, and calves were weighed weekly.
For the cows, no significant differences were found between the two separation methods in any of the used behavioral or physiological indicators. However, both methods led to an increase in vocalizations and searching behaviour compared to baseline at several time points, as well as to a transient increase in physiological stress markers, indicating that both methods provoked stress for the cows. For calves, the abrupt milk loss through the nose flap seemed to compromise adaptation of the gastrointestinal tract and led to low weight gains, reduced play behaviour and an increase in inflammatory blood markers. Furthermore, calves with nose flaps exhibited a marked decrease in lying and play behaviour, along with a high number of unsuccessful suckling attempts, which pointed towards a negative emotional state in NF calves. In contrast, GR calves showed higher weight gains, a lower decrease in lying bouts as well as a lower decrease in locomotor play levels during weaning compared to baseline, indicating a better adaption of the gastrointestinal tract to the dietary change as well as a likely less compromised affective state. In addition, the nose flap had caused pressure marks and injuries at the nasal septum of calves after the 14 days of usage. Results from our video analyses suggested that the calves needed to wear the nose flap for at least 4 days in order to effectively reduce suckling motivation, while there seems to be no benefit of using nose flaps longer than this time. However, it could not be determined whether nasal septum injuries were already present in our NF calves after the 4 days of usage.
Given the overall beneficial effect of the gradual weaning and separation method for the calves and the missing difference in cows, the GR method seems overall favorable to reduce weaning and separation stress for cow-calf pairs compared to the NF method. Nonetheless, the GR method also caused considerable stress for the animals and recommendations for refinement are given in the thesis, highlighting, among others, the need to truly reduce the milk intake of calves and to focus on loosing established routines rather than just contact time itself.
With regard to the stress indicators, it became evident that a low frequency of vocalizations during weaning should not be taken as evidence of low stress levels of animals, if not backed by further indicators. Relative telomere length as sampled in the present thesis was not a valid indicator of cumulative separation stress, while calves’ fecal cortisol metabolite concentrations were found to be a generally valid stress indicator for (unweaned) dairy calves, but unsuitable for comparing pre- and post-weaning states.
In conclusion, this thesis provides valuable new insights to improve the weaning and separation process in CCC systems, that directly support practical applications as well as future research on this topic.
Research on CuxTi1-xO2 Thin Films Acting as Buffer Layers for VO₂-Based Smart Window Applications (Raw data)
(2025-03-26) Hao Lu
This folder contains the raw experimental data of Cu-doped TiO₂ thin films, which will be used for the writing and publication of my scientific paper. It also includes some optical data of VO₂ films grown on CuTiO₂ buffer layers.
About experiment:
The CuxTi1-xO2 layers were deposited by radio-freqency (RF) sputtering on quartz substrates (Suprasil). We used a 4-inch target of ceramics TiO2 at a distance of 4 inches from the substrate. In order to alloy the TiO2 thin films with Cu, several pure Cu lines were mounted onto the target manually. This combination allowed us to achieve CuTiO2 alloy with various Ti:Cu ratios and, thus, to deposit CuxTi1-xO2 thin films. All thin films were sputtered to obtain a thickness from 100 to 200 nm at 200°C to 400°C heater temperature. A mixture of Ar and O2 with a pressure of 3.4×10−3 mbar were used to generate the plasma. The O2 gas flux was varied between 0–3 sccm at a fixed Ar flux of 31 sccm. Anatase and rutile thin films were prepared by ion beam sputtering at room temperature and 560°C, respectively. VO2 thin films were prepared via RF sputtering using a 4-inch metallic vanadium target. The deposition temperature of the VO2 films was controlled within the range of 300°C to 400°C. The RF plasma was generated using a mixture of Ar and O2 gases at a pressure of 3.4×10−3 mbar. The gas flux ratio was set at 1.1 sccm for O2 and 31 sccm for Ar. All VO2 thin films had a thickness of 50 nm.
The layer thicknesses and densities were analyzed with X-ray Reflection (XRR). The film structure was analyzed with Grazing-Incidence X-Ray Diffraction (GIXRD). In this mode of XRD, the X-rays are incident on the sample at a grazing angle, meaning they skim along the surface rather than striking it directly perpendicularly. Thus, this shallow angle enables an enhanced sensitivity to surface structures. Both, XRR and XRD, were performed using a Rigaku SmartLab diffractometer that operates a 9 kW rotating Cu anode. X-ray Photoelectron Spectroscopy (XPS) was employed for the comprehensive analysis of both the elemental composition within the film and the valence states inherent to each individual element. We used a PHI VersaProbe II spectrometer with a monochromated Al Kα (1486.6 eV) X-ray anode directed at 45° towards the surface normal. Charge compensation was achieved using a combination of an electron gun and an Ar+ ion gun. The samples were exposed to a focused Ar+ beam at an acceleration voltage of 1 kV to remove adsorbed impurities. Raman spectroscopy with 515 nm laser excitation and a spectral resolution of 1.5 cm−1 (Renishaw inVia Raman microscope system) was used for phase identification of the CuxTi1-xO2 and VO2 thin films, providing complementary confirmation to the findings obtained by XRD. A Zeiss-Merlin scanning electron microscope (SEM) equipped with an InLens detector was used for investigating the film morphology. Optical transmittance measurements were conducted using a PerkinElmer Lambda 900 UV–Vis–NIR spectrometer. For temperature-dependent measurements, a resistively heated sample holder, controlled by a Eurotherm heating controller and integrated with a Peltier cooling device, was used to achieve precise heating and cooling rates. A PT100 sensor was employed to monitor the sample's actual temperature. Optical simulations were conducted using the Essential MacLeod software, based on optical constants obtained from spectroscopic ellipsometry for all constituent layers, TiO2, VO2 and CuxTi1-xO2, respectively.
Effekt von BDNF auf die Angiogenese im humanen Kokultursystem aus Endothelzellen und osteoporotischen Osteoblasten
(2025) Holtkamp, Katharina Ines Carmen
Die Bildung und Stabilisierung von Blutgefäßen ist für die Frakturheilung von entscheidender Bedeutung. Im Herz konnte gezeigt werden, dass das Signalmolekül brain-derived neurotrophic factor (BDNF) die Angiogenese fördert. Vor diesem Hintergrund stellte sich die Frage, ob durch eine Applikation von BDNF die Bildung von Blutgefäßen stimuliert wird und ob die Osteoblasten osteoporotischer Spender hierbei regulierend wirken. Angelehnt an die gestellte Hypothese konnte kürzlich aufgezeigt werden, dass mesenchymale Stammzellen (MSC) und Osteoblasten bei Osteoporose phänotypische Veränderungen im Vergleich zu knochengesunden Zellen aufweisen. Zur Beantwortung der Frage wurden humane Osteoblasten und Endothelzellen im Kokultursystem untersucht. MSC wurden aus humaner Spongiosa isoliert, die bei der Endoprothetik als Restmaterial anfiel. Es wurden MSC von n = 5 knochengesunden und n = 5 osteoporotischen Spendern verwendet. Für das Kokultursystem wurden die MSC 10 Tage osteogen differenziert. Anschließend wurden immortalisierte humane dermale mikrovaskuläre Endothelzellen (HMEC), in einem Verhältnis von 1:4, sowie BDNF (20 ng/mL Medium) hinzugefügt. Nach 3 und 5 Tagen wurde der von-Willebrand-Faktor (vWF) im Zellkulturmedium mittels ELISA bestimmt. Die Zellen wurden ebenfalls nach 3 und 5 Tagen geerntet und zur Bestimmung der relativen alkalischen Phosphatase (ALP) Aktivität verwendet. Abschließend erfolgte eine statistische Analyse und graphische Darstellung. Die Konzentration des sezernierten vWF im Zellkulturmedium stieg von Tag 3 zu Tag 5 signifikant in Kokulturen mit humanen Osteoblasten von osteoporotischen Spendern nach Zugabe von BDNF an. In Kokulturen knochengesunder Osteoblasten konnte ein vergleichbarer Anstieg der vWF Konzentration auch ohne die zusätzliche Applikation von BDNF gemessen werden. Die Differenzierung und Aktivität der Osteoblasten wurde durch die relative Aktivität der ALP ermittelt. Es waren keine signifikanten Unterschiede in der ALP Aktivität in den Kokulturen knochengesunder und osteoporotische Osteoblasten, sowie nach Applikation von BDNF zu verzeichnen.
Die Ergebnisse zeigen, dass Osteoblasten osteoporotischer Spender nach Zugabe von BDNF keinen negativen Einfluss auf die Bildung des vWF und somit auf die Angiogenese ausüben. Diese stimulierende Wirkung von BDNF ist in Kokulturen knochengesunder Osteoblasten nicht notwendig. BDNF zeigte im Kokultursystem mit humanen Endothelzellen keinen Einfluss auf die ALP Aktivität, die als Zeichen für die Aktivität der Osteoblasten verwendet wurde. Zusammenfassend zeigte sich durch BDNF eine positive Beeinflussung der osteoporotischen Kokultur in Bezug auf die Angiogenese, womit ein zukünftiger Ansatz im Umgang mit Osteoporose aufgezeigt werden konnte.