DWI – Leibniz Institute for Interactive Materials
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SERCA2, MuRF1 und MAFbx in Heparansulfat-stimulierten HL-1-Kardiomyozyten und im murinen Sepsismodell und der Einfluss des synthetischen Peptids 19-2.5
No full textConfounding effects of blood hemoglobin and hematocrit levels on flap perfusion measurement with the Oxygen-to-see (O2C) analysis system in microvascular head and neck reconstruction– a retrospective study
No full textKompensation thermischer Linseneffekte in optischen Systemen für die Lasermaterialbearbeitung
No full textIn laser material processing, optical systems are used e.g. for beam guidance and shaping. Particularly with laser powers in the multi-kilowatt range, the absorbed laser light leads to heating of the optical elements. One consequence is the so-called thermal lens effect. The thermal lens effect leads to a change in the focal length of the optical system and thus to a shift in the focal position relative to the workpiece. This can lead to reduced machining quality or even to an abortion of the machining process. This thesis therefore investigates various concepts for active and passive compensation of thermal effects. A passive approach for the compensating of thermal effects is investigated using the example of plastic optics for a laser power of 15 W. Compared to glass optics, plastic optics exhibit thermal effects that are about 100 times greater at the same laser power, which is why their range of application has so far been limited to optical systems with laser powers <<1 W. On the other side, they offer considerable cost-saving potential due to their injection molding production. Passive compensation of thermal effects through a different combination of thermoplastics is not possible due to their similar material parameters. This work therefore pursues a passive approach in which the geometry of an existing plastic lens is adapted for a specific operating condition. This approach extends the power range that has been effectively usable to date. To this end, the laser and material parameters relevant to the thermo-optical design are first identified using a sensitivity analysis and measured using various measurement methods. The lens geometry is then optimized for the operating condition based on the laser and material parameters. The adapted lens geometry is produced by injection moulding and then characterized with regard to its optical properties. The compensated lens geometry has a Gaussian intensity distribution in the focal plane but deviates from the target value by 27% in terms of its focal length. The thermal effects during the laser machining process can also be intensified by process-related contamination of the optics, in particular the protective glass. In practice, the protective glass is therefore replaced at regular intervals. By compensating for the thermal effects over time, it would be possible to extend the necessary service intervals or increase the process accuracy. Due to the temporal change of the thermal effects that occur, passive compensation is not possible here. As an alternative, active compensation of thermal effects is therefore demonstrated using a new type of measurement and control system. The measurement of the focus position is based on the evaluation of the characteristic diffraction pattern of an amplitude mask integrated into the beam path, the so-called Bahtinov mask. The diffraction pattern is evaluated using different evaluation algorithms. Following experimental validation, the measurement concept is being further developed for coaxial integration in almost any laser material processing system. Measurements show a determination of the focus position over a range of ±2.5 mm with an average deviation of 42.52 μm
Aufklärung des Effekts von Nrf2 auf parodontale Erkrankungen in vitro
No full textPeriodontal diseases (PD) are among the most significant health issues worldwide. They are caused by bacterial infections, including Porphyromonas gingivalis (P. g.), which can damage the periodontal ligament and alveolar bone, leading to tooth loss and a significant reduction in quality of life. Lipopolysaccharide (LPS) from P. g. is considered a critical factor in the onset and development of PD, as it induces the formation of intracellular reactive oxygen species (ROS). The accumulation of ROS leads to oxidative stress, influencing the progression of PD and degrading nuclear factor erythroid-derived 2-related factor 2 (Nrf2), which plays a crucial role in bone healing. This study investigates the impact of LPS-P. g. as an ROS inducer and methysticin as an Nrf2 activator on the proliferation and mineralization of preosteoblasts from the MC3T3-E1 (subclone 4) cell line. Cells were cultured in α-MEM and stimulated with LPS-P. g. (STD and ULT). NF-κB activity was determined using a dual luciferase assay, while cell proliferation and cytotoxicity were assessed using the CyQUANT® Cell Assay. Mineralization was evaluated by Alizarin Red staining of calcium deposits after a 28-day differentiation process, and ALP activity was measured. The protein concentration of IL-6, IL-1ß, VEGF, and TNF-α was determined using sandwich ELISAs. Results showed weak activation of NF-κB in MC3T3-E1 cells compared to RAW 264.7 macrophages after stimulation with 1µg/ml LPS-P. g. (STD). LPS-P. g. (STD and ULT) had no inhibitory effect on cell proliferation. However, LPS P. g. (STD) could inhibit the differentiation of MC3T3-E1 cells and their ALP activity. Conversely, methysticin positively affected ALP activity and mineralization. Injection of LPS-P. g. (STD) increased IL-6 expression and decreased VEGF expression. In summary, the concentration of 1µg/ml LPS-P. g. (STD) used is significantly above the physiological range and could cause decreased mineralization of MC3T3-E1 cells due to inflammation or increased ROS formation. Methysticin, due to its antioxidative properties, could potentially be developed as a drug for the treatment or prevention of PD in the future. However, its toxicity needs to be considered in the overall assessment
Die Dynamik von Geschwisterbeziehungen: Messung von Aggression und Dominanz in interaktiven Paradigmen und ihre Auswirkungen auf die Hormonregulation
No full textDue to their family background and shared experience of conflict, siblings represent a particularly interesting target group for studying competitive behavior. The steroid hormones testosterone and cortisol have already been linked to status-relevant behavior in several studies. The aim of the present study was to investigate the behavior of siblings using two interactive competition tasks and their effects on hormone levels. The influence of personality factors and the effect on aggression and dominance were examined. 20 same-sex (10 male and 10 female) sibling pairs competed against each other in two paradigms measuring dominance and aggression (interactive chicken game and interactive Taylor aggression paradigm). Saliva samples were taken before and after each task to measure cortisol and testosterone. The participants answered questions about their sibling relationship (Sibling Type Questionnaire, STQ) beforehand and personality questionnaires on anger, status-relevant behavior and competition after the study. Based on the information provided by the siblings in the STQ, they were divided into cooperative and competitive siblings, with more males falling into the competitive cluster and more females into the cooperative clusterGender differences were also observed in testosterone levels. A significant change in cortisol levels over time was observed. No sufficient effect on hormonal regulation could be demonstrated for the paradigms, nor was there a correlation between self-reported personality factors, competitive behavior, hormone levels and cluster assignment. Future studies should consider a larger sample size and other influencing factors, such as socio-cultural factors. The study suggests gender differences in status-relevant behavior and hormone regulation but does not capture all relevant aspects to explain the interplay of competitive behavior, hormone regulation and personality factors
