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Item type: Item , Können Plaqueindizes die tatsächliche Plaquemenge abbilden?(2025) Eilert, FranziskaFür die zahnmedizinische Prävention spielen plaquereduzierende Maßnahmen eine zentrale Rolle. Um einschätzen zu können, ob Mundhygienemaßnahmen effektiv sind und inwieweit sie die mikrobielle Besiedlung der Zahnoberflächen reduzieren, kommen heute verschiedene Methoden der Plaquequantifizierung zum Einsatz. Die zwei gängigsten Verfahren sind die Plaqueplanimetrie und der Einsatz von Plaqueindizes, wobei sich Letztere in ihren Differenzierungsgraden teils deutlich unterscheiden. Folglich wird die vorhandene Plaquemenge indexabhängig unterschiedlich abgebildet, was wiederum einen Einfluss auf die Vergleichbarkeit zwischen Studienergebnissen hinsichtlich der ermittelten Effektgröße und statistischen Signifikanz nimmt. Bei der Planimetrie hingegen wird die vorhandene Plaque objektiv durch eine Computersoftware als prozentualer Anteil an der Gesamtoberfläche errechnet. Ziel der vorliegenden Arbeit war es herauszufinden, inwiefern verschiedene Indizes in der Lage sind, die planimetrisch gemessene, tatsächliche Plaquebedeckung, auch zu unterschiedlichen Zeitpunkten der Mundhygiene, darzustellen. Der Erkenntnisgewinn diente unter anderem der kritischen Auseinandersetzung mit der Aussagekraft von vorherigen klinischen Studien. Hierzu wurden Intraoralscans von 30 Probanden zu jeweils drei unterschiedlichen Zeitpunkten der Mundhygiene angefertigt. Der erste Termin repräsentierte dabei die habituelle Mundhygiene (T1). Beim zweiten Termin stellten sich die Probanden nach 72 Stunden ohne Mundhygiene vor (T2), wurden anschließend dazu aufgefordert ihre Zähne wie gewohnt zu putzen und unterzogen sich dann dem dritten Intraoralscan (T3). Vor jeder Datenerfassung wurden die vorhandenen mikrobiellen Beläge durch einen Plaquerevelator (Mira-2-Ton®) sichtbar gemacht. Anhand der ermittelten 3D-Scans wurden standardisierte Screenshots der Vestibulär- und Oralflächen der Ramfjordzähne erstellt und die Plaquemenge mithilfe eines Grids hinsichtlich vier verschiedener Indizes ausgewertet (T-QHI, RMNPI, RMNPI nach Bretz, marginaler Plaqueindex). Im Anschluss erfolgte die Messung der tatsächlichen Plaquebedeckung mithilfe der Planimetrie. Es konnte gezeigt werden, dass zwar alle Indizes Plaquemengenveränderungen widerspiegeln können, diese aber in einer deutlich abweichenden Effektgröße repräsentiert werden. Die Indexwerte fielen immer signifikant niedriger als die planimetrisch erhobenen Messergebnisse aus, zudem bestand ein nichtlinearer Zusammenhang. Insgesamt lieferte der T-QHI noch die zuverlässigsten Ergebnisse, kann aber auch nur eingeschränkt einen Anhalt auf die tatsächliche Plaquemenge geben. Schlussfolgernd ist es also nicht sicher möglich Effektgrößen mithilfe von Plaqueindizes auszudrücken.Item type: Item , Ein Schatz aus dem späten 16. Jahrhundert: ein Nürnberger Gesangbuch(2025) Schneider, OlafItem type: Item , Unraveling the role of heterotrophic feeding in coral tolerance to ocean warming and microplastic pollution(2025) López Hernández, María Antonieta PanamáCoral reefs harbor the highest biodiversity of all marine ecosystems and support the livelihoods of nearly 500 million people worldwide. Yet, they are increasingly threatened by global warming. Marine heatwaves disrupt the symbiosis between corals and Symbiodiniaceae algae, leading to coral bleaching. As these algae provide up to 90% of coral energy requirements, their loss results in energy deficits that compromise coral health, reducing growth and reproduction, increasing disease susceptibility, and often leading to mortality. Heterotrophic feeding, as a secondary pathway of energy acquisition in reef-building corals, can sustain up to 100% of their metabolic demands under stress, thereby enhancing survival and resilience to bleaching caused by ocean warming. Consequently, trophic plasticity, i.e., the ability to modulate trophic strategies in response to environmental change, has emerged as a key trait distinguishing potential “winners” under climate change. However, trophic plasticity varies among species and may be compromised by emerging stressors such as microplastic pollution, which can interfere with coral feeding. Despite the importance of heterotrophy in coral resilience, there are still knowledge gaps regarding the role of food type and food availability on coral physiology, and how these interact with pollutants such as microplastic, particularly in an ocean warming context. These uncertainties are further compounded by a lack of field-based data. This thesis addresses these knowledge gaps through two controlled laboratory experiments and the first in situ application of compound-specific isotope analysis of amino acids during a natural bleaching event. Five coral species (Galaxea fascicularis, Porites lobata, Stylophora pistillata, Ctenactis echinata, and Pocillopora verrucosa) were assessed for key physiological traits (photophysiology, growth, energy reserves, δ¹⁵N and δ¹3C), providing a comparative framework of heterotrophic strategies. Results indicated that complex diets enhanced the benefits of heterotrophy across coral species. Although these benefits varied among species when symbiotic, all bleached corals exhibited positive responses to more complex food sources. Physiological rates were consistently higher in symbiotic fragments compared to their bleached counterparts, with the magnitude of these differences increasing alongside the baseline productivity of the species, from G. fascicularis to P. lobata and S. pistillata. Food treatments did not affect respiration or photosynthetic rates, suggesting that growth gains were driven primarily by enhanced heterotrophic nutrient supply. In situ bleaching was associated with δ¹⁵N enrichment in the trophic amino acids alanine (ALA), glutamic acid (GLU), isoleucine (ISO), proline (PRO), and valine (VAL), suggesting alterations in nitrogen acquisition and processing under stress. The trophic position (TP) of the symbiotic host and symbionts of C. echinata was 1.3, consistent with a mixotrophic diet. In contrast, P. verrucosa exhibited TP values of 1.2 for the host and 1.0 for the symbionts, indicating a stronger reliance on autotrophy. Under bleaching, C. echinata maintained a TP of 1.4, reflecting a stable mixotrophic strategy, whereas P. verrucosa shifted to a TP of 1.5, suggesting an increased reliance I on heterotrophy. These findings suggest higher heterotrophic plasticity in P. verrucosa compared to C. echinata. Microplastics (MPs) exposure significantly decreased the energy reserves of P. verrucosa, although it increased photosynthesis and respiration. High food availability partially mitigated the loss of tissue energy content observed while maintaining photosynthesis and respiration rates comparable to control conditions. S. pistillata was not affected by MP exposure alone, but when combined with high feeding, photosynthesis decreased below that of the Control. When exposed to short-term heat stress, all corals bleached severely, however, both species bleached less in the MP treatment suggesting that MPs may also disrupt the relationship between energy balance and thermal resilience. Overall, this thesis provides evidence supporting the central role of heterotrophic feeding in modulating coral tolerance to the combined pressures of ocean warming and microplastic pollution, while emphasizing the need to integrate trophic plasticity and interspecific variability into future conservation and management strategies.Item type: Item , Predictive Modelling with Machine Learning in Plant Breeding(2025) Heilmann, Philipp GeorgGenomic prediction, originally proposed as a solution to the limitations of marker-assisted selection for complex traits, has become the standard for estimating breeding values in both inbred and hybrid crops. While linear models such as GBLUP and RR-BLUP remain effective in many cases, especially when assuming an additive genetic architecture, recent years have seen a growing interest in applying machine learning (ML) methods to overcome some of their constraints, including their limited capacity to model non-additive effects and nonlinear interactions. This thesis explored the influence of three key aspects on the success of genomic prediction: The choice of input features, the statistical model used, and the target trait or crop.
In terms of input features, marker data was compared to minimalist parentage-based models, haplotype blocks, and features generated using autoencoders. It was shown that even simple ML models using parentage-based information can rival marker-based GBLUP under certain conditions, which holds potential for small breeding programs with large amounts of historical, but ungenotyped, records. At the same time, dimensionality reduction techniques, especially a novel haplotype-based autoencoder that was developed during this thesis, were introduced to compress genomic data while preserving prediction accuracy and successfully accelerated model training.
Concerning the model aspect, a variety of ML algorithms were benchmarked using different approaches for hyperparameter tuning. Although no single model outperformed others across all traits and crops, ensemble approaches typically performed better than the individual models they were based on. Support vector machines seemed to be relatively unstable when compared to other ML based algorithms, such as tree-based models.
Finally, results showed that the accuracy of the genomic predictions was strongly dependent on differences between traits, crops with different breeding schemes, and different populations. For hybrids, ML performed well when SCA was more important for determining the hybrid yield than GCA. Large differences were observed for different fungal diseases in wheat, while differences among methods for the same disease were relatively similar.
While ML has not yet provided a significant improvement over traditional methods in many scenarios, its flexibility and potential for multi-modal data integration remain promising. The development of plant breeding-specific model architectures, such as haplotype-based autoencoders, may represent a more promising path than the general application of standard ML models.Item type: Item , Impact of compressive force on macrophages and cementoblasts and the possible interrelation with orthodontically induced inflammatory root resorption(2025) Wang, YaoThis study analyzes the impacts of orthodontic compressive force on both innate immune responses and cementum homeostasis (Figure 22). In macrophages, compressive force induces chromatin rearrangement, nuclear shrinkage, and polarization. Two distinct mechanotransduction pathways were identified: 1. Histone H3 hyperacetylation: This mediates M2 polarization during the late stage of the immune response. 2. Lamin A/C downregulation: Orthodontic compressive force transiently reduces lamin A/C levels, compromising the nuclear envelope and increasing nuclear permeability to YAP1. This facilitates enhanced force-induced cytokine expression and proliferative inhibition. Concurrently, it reduces force-induced IRF4 expression, DNA damage, and phagocytosis enhancement, likely due to LINC complex disruption. These opposing effects of lamin A/C deficiency jointly regulate cellular behavior under compressive force. Furthermore, cementoblasts respond directly to compressive force but do not respond to macrophage-conditioned medium, suggesting that excessive orthodontic force, rather than macrophage activation, is the primary driver of OIIRR. Mechanistically, Piezo1 activation under force mediates enhanced hypoxia and suppressed mineralization in a Ca2+-independent manner. Lastly, LMCD1 and POSTN were identified as downstream mediators of Piezo1, representing potential therapeutic targets for OIIRR.