Esta tesis doctoral se ocupa de la historia del concepto de democracia en Chile a mediados del siglo xx. A través de un enfoque de historia conceptual, se explora la manera en que la democracia fue interpretada, conceptualizada y representada en el panorama político e intelectual chileno entre 1945 y 1964. La propuesta entiende la democracia, en tanto régimen de gobierno, conformada tanto por principios como por una naturaleza institucional. Se argumenta que dos de estos principios, el pueblo y la historia, tuvieron un rol central en la configuración conceptual de la democracia chilena durante el período. Estos principios dotaron a la democracia de valores, imágenes y una proyección en el tiempo. También colaboraron en dotar al fenómeno democrático con la particularidad e importancia que alcanzó durante el siglo XX en Chile y el mundo, especialmente después de 1945. Se sostiene que, tras el fin de la Segunda Guerra Mundial, la democracia y su vocabulario se volvieron referencias ineludibles, impregnando una variedad de corrientes ideológicas y sensibilidades intelectuales en todo el espectro político. Pero no con el mismo sentido ni trasfondo conceptual. Acontecimientos y procesos de la historia mundial, en tanto, acompañan la comprensión del concepto, su apertura a nuevos significados, sus asociaciones teóricas. Con el fin de complejizar el panorama político e intelectual chileno de estas décadas, esta investigación ha considerado precisamente algunas posiciones críticas al “modelo occidental” de democracia liberal. Así, la tesis se estructura según tres ejes centrales: primero, el pensamiento de la izquierda marxista, en especial de los partidos Comunista y Socialista; segundo, el pensamiento socialcristiano asociado a la Falange Nacional, la Democracia Cristiana y expresiones no partidistas del catolicismo social; y, tercero, el pensamiento de derecha, en sus vertientes conservadora, tradicionalista y nacionalista. En cada uno de estos ejes se explora el concepto de democracia, sus mutaciones y la configuración que en cada corriente se le atribuyó al orden político y social del país. Cada eje contuvo una elaboración conceptual de la democracia enriquecida con ideas sobre el pueblo y la historia: esto es, cada corriente incluyó una idea sobre la entidad colectiva que habría de legitimar o ejercer el poder, así como una interpretación sobre la democracia a través del tiempo. Se pensaba, en general, que la democracia moderna no había dado aún cuenta del pueblo y su misión, y que los fundamentos de una “democracia verdadera” debían por lo tanto ser buscados en otra parte. La tesis propone, finalmente, que la democracia en Chile fue conceptualizada y representada prioritariamente desde sus principios, en paralelo u oposición con su carácter formal e institucional. En tanto régimen de gobierno, la democracia ha sido indisociable de una narración sobre sí misma.

In this thesis the biophysical properties of four phytochromes were investigated to understand the enhancement mechanism of fluorescence in phytochrome-based near-infrared fluorescent proteins and to understand the contribution of the protonation heterogeneity to the function of phytochrome. Phytochromes are red/far-red photosensor proteins found in many organisms, such as plants, bacteria or fungi. The investigated phytochromes are Cph1 and Cph2 from cyanobacteria, as well as Agp1 and Agp2 from the Agrobacterium tumefaciens. The photosensor itself is a linear tetrapyrrole, which is bound to the photosensor module of phytochrome comprising the PAS, GAF and PHY domain (in short PGP) for Cph1, Agp1 and Agp2. In the first part (Chapter 4 and 5), we performed pH-titration of the linear tetrapyrrole chromophore in the Pr (red absorbing) state of different Cph1 PGP and Agp1 PGP constructs. Moreover, the role of the chromophore type such as biliverdin (BV) and phycocyanobilin (PCB) in phytochrome protonation heterogeneity in the Pr state was investigated using covalent and non-covalent PCB binding to Agp1 PGP V249C and wildtype (WT), respectively. The structural changes at various positions in Cph1 PGP and Agp1 PGP were measured as a function of pH using picosecond time resolved fluorescence anisotropy. We showed that only in Cph1 PGP, a direct correlation of chromophore deprotonation with pH-dependent conformational changes was found, but not in Agp1 PGP. In the second part (Chapter 6 and 7), we characterized the fluorescent properties of several variants from two different phytochrome families: phycocyanobilin-binding phytochromes (Cph1 and Cph2) and biliverdin-binding bacteriophytochromes (Agp1, und Agp2, as well as the variants of PAiRFP2), using steady-state and time-resolved fluorescence spectroscopy. The PCB adducts of Agp1 PGP variants were characterized to test the effect of chromophore type and conserved amino acids in the chromophore binding pocket on fluorescence quantum yield and fluorescence lifetime. Our results on Cph1 indicated that the combination of mutations known to enhance fluorescence in the cyanobacterial phytochrome Cph1 yield a quantum yield of about 17%. Also, our results confirmed a remarkable higher fluorescence quantum yield of phycocyanobilin-binding phytochromes (Cph1 and Cph2) compared to biliverdin-binding bacteriophytochromes (Agp2 and PAiRFP2), as it was shown in the previous studies.

The aim of this dissertation is to construct and develop a theory of “personal commitment”, and defend it in the context of other existing approaches. The first part of this dissertation introduces some practical examples that help explain the plausibility of the idea of personal commitment. Roughly, a personal commitment is understood as willing something to be a reason for you. A formerly optional endeavor becomes something that one now ought to pursue. Personal commitments are a crucial component of human agency because they promise some control over one’s identity and are expressive of agential activity. The concept promises the opportunity to color one’s own life. Several desiderata of a plausible account of personal commitment that prove to be essential are introduced. It becomes apparent that personal commitments cannot be adequately captured in the language of intentions or promises. On the basis of this conjecture, it is examined in great detail whether personal commitments can be understood as being a subcategory of intentions or promises after all, and, if not, how a theory of personal commitment differentiates from existing ones. It becomes evident that personal commitments obligate without having moral weight attached to them. Intentions and promises cannot capture the appeal of personal commitments because they are either too weak or too strong. Furthermore, personal commitments are distinguishable from so-called volitional necessities because they understand volitional activity simply as being satisfied with one’s dispositions. This is not the case with personal commitments. Thus, personal commitments should not be understood as a subcategory of an already existing concept but as an independent phenomenon. This is being demonstrated particularly well by the stark contrast. The uniqueness of personal commitments consists in the fact that they can be entered and exited at will, however, without falling victim to arbitrariness. This is yet another important highlight of the approach. Personal commitments should subsequently be understood as willing something to be a reason for you that is followed by the demands of proper engagement. This theory of personal commitment adds to the existing discourse on will-based commitments by being in a better position to be able to explain an important part of practical life. The relevance of this inadequately considered idea to date of personal commitment underlines the significance of this dissertation.

Stress responses are fundamental for the survival of an organism and constitute an adaptive reaction to a real or perceived threat. Neuronal, endocrine, and behavioral responses are activated after the perception of a stressor and are aimed to re-establish the organism's homeostasis. A complex network of neuronal circuits involving several brain regions orchestrates the activation of the major stress system, the Hypothalamic Pituitary Adrenal (HPA) axis, and most of the neuronal populations that control its activity reside in hypothalamic nuclei. Activation of the HPA axis starts within the paraventricular nucleus of the hypothalamus, in which a population of peptidergic neurons secretes corticotropin-releasing hormone (CRH) into the circulation, which in turn initiates a signaling cascade culminating with the production of cortisol. The activity of the HPA axis and CRH-producing neurons must be tightly controlled and rapidly modulated to ensure proper responses to threats but also to avoid overactivation of the stress system, which is deleterious for an animal’s wellbeing. However, the hypothalamic circuits responsible for the activation and termination of the stress response and the underlying neuromodulatory mechanisms are still largely unknown. In this study, I used the zebrafish larva as a model to elucidate the hypothalamic neuronal circuits modulating the behavioral and neuroendocrine responses to acute stress. The transparent and small larval zebrafish brain provides the unique opportunity to study neuronal responses in vivo, facilitating the identification of the neuronal populations modulating stress. Importantly the main brain regions and stress axes are conserved between mammals and teleosts. The Hypothalamic Pituitary Interrenal (HPI) axis is homologous to the mammalian HPA axis and its activation is controlled by Crh-producing neurons located in the preoptic area (PoA), homologous to the mammalian paraventricular nucleus. Among the peptidergic neurons of the hypothalamus that might be involved in the modulation of acute stress, I chose to focus on a population of cells secreting the neuropeptide Galanin (Galn). I identified in the PoA of zebrafish a subpopulation of Galanin-producing neurons (Galn+) highly responsive to different types of stressful stimuli. Ablation of Galn+ neurons led to exacerbated stress responses, elevated cortisol levels, and caused increased activation of Crh-producing neurons, suggesting an inhibitory effect of Galn+ neurons over the HPI axis. I also found that Galn+ neurons in the PoA of zebrafish larvae are GABAergic, suggesting the possibility that GABA is the neurotransmitter released by Galn+ neurons to inhibit downstream stress-promoting circuits. I further investigated the molecular mechanisms by which Galn+ neurons negatively modulate stress responses by manipulating the peptide Galn. Lack of Galn elicited a diminished response to stress and increased the activity of Galn+ neurons in the PoA. Conversely, overexpression of Galn exacerbated stress- related responses and decreased the activity of Galn+ neurons, suggesting a self-inhibitory action of Galn peptide on Galn+ neurons. Taken together, the results reported in this study indicate that Galn+ neurons in the PoA negatively modulate Crh+ neurons, likely through GABAergic transmission, to prevent overactivation of the HPI axis. In parallel, the neuropeptide Galn mediates an additional modulatory control within this hypothalamic circuit, reducing the activity of Galn+ neurons through an autocrine mechanism. This dual system likely regulates a balance of activation and inhibition over Crh+ neurons, which allows fine-tuning of the HPI axis activity and mediate behavioral responses to stress.

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases (prevalence 0.5-1.0%), which can lead to pain and a considerable loss of life quality in affected patients. Many details of underlying causes and mechanisms are still elusive. The persistent autoimmune-mediated inflammation of the joint is one of the key features of this systemic, chronic-inflammatory disease accounting for progressive cartilage destruction. Despite major progress in the treatment of RA, a strong unmet medical need remains. Therefore, a better understanding of the underlying pathomechanisms driving RA progression is required to develop new therapeutic strategies to effectively treat patients at every stage of disease progression. Although various RA models already exist, they either employ phylogenetically distant species or rely on human cells cultured in an oversimplified environment. To date, none of these models allows sufficient or complete extrapolation to the human patient. Therefore, the use of human-based in vitro 3D tissue equivalents of an artificial joint is a promising alternative approach to investigate pathomechanisms and test new therapeutic approaches. Hence, the aim of this thesis was to develop and characterize human in vitro 3D tissue equivalents of the joint, namely (i) cancellous bone, (ii) articular cartilage, and (iii) synovial membrane using bone marrow-derived mesenchymal stromal cells (MSCs). Here, MSCs provide the possibility of producing a complete joint model from single donor material thus offering the opportunity of a personalized testing platform. The results described in this thesis show the potential of mimicking key features of arthritis in three different tissues of a joint. Firstly, to simulate the bone component, β-tricalcium phosphate (TCP) – mimicking the mineral bony part – was populated with MSCs. Cell seeding was optimized using cell sheet technology. In contrast, the cartilage component was produced by cellular self-assembly without any supporting materials. Both models exhibit phenotypic features of native tissue, including expression of bone- or cartilage-related markers, mineralization of bone that was absent in cartilage, and development of distinct zones in the glycosaminoglycan-rich cartilage model. Co-cultivation of both tissue models generated the osteochondral unit characterized by inter-tissue connectivity, cell colonization, and initial calcification implying a functional transitional bridging area. Finally, the synovial membrane model was generated based on a xeno-free synthetic hydrogel populated with MSCs indistinguishable from synovial fibroblasts with regard to classical markers. Similar to the human synovial membrane, a confluent layer of up to four cell layers was detectable within the hydrogel allowing immune cell migration. To simulate inflammation, the individual tissue components were treated with cytokines relevant for RA, such as interleukin-6, tumor necrosis factor-α, and macrophage migration inhibitory factor. This resulted in cytokine-driven cell- and matrix-related changes in accordance with those observed during RA, while treatment using biologics prevented the induction of arthritis in the osteochondral model. These results confirm the pathophysiological mutability, architecture, integrity, and viability of the distinct in vitro 3D joint components. Prospectively, the complete in vitro 3D joint model will serve as a preclinical test platform in basic and applied biomedical research to (i) study pathophysiological processes of musculoskeletal diseases, (ii) identify new potential targets, (iii) test novel therapeutic strategies, including biologic therapies, and (iv) reduce the number of animal experiments.

Adoptive T cell therapy with T cell receptor (TCR) engineered T cells is a promising approach for cancer treatment. Target antigens are categorized into tumor-associated antigens (TAAs) and tumor-specific antigens (TSAs). TAAs are overexpressed on cancer cells and often shared between different cancers, however, targeting TAAs has the risk of inducing autoimmune responses. In contrast to TAAs, TSAs are expressed exclusively on cancer cells, but only some of them are shared between patients. Since drug-selected secondary mutations in chronic myeloid leukemia (CML) are both cancer-specific and shared between patients, they become attractive targets. CML is a myeloproliferative disease. Over 95% of CML cases are associated with Philadelphia (Ph) chromosome t(9;22). Such abnormal chromosome results in the BCR-ABL hybrid gene that encodes a constantly active tyrosine kinase. Currently, tyrosine kinase inhibitors (TKIs) are used as the first-line treatment, as they effectively avoid uncontrollable cell division by blocking the ATP binding site of the kinase. Nevertheless, drug resistance is often observed due to drug-selected secondary mutations that prevent the TKIs from binding to the BCR-ABL protein. As relapsed CML patients with compound mutations are resistant to most or all TKIs, TCR gene therapy could benefit these patients.

In this project, we aimed to discover neoepitopes from drug-selected secondary mutations in CML and to generate neoepitope-specific TCRs for clinical use. ABabDII mice expressing a human TCR repertoire and HLA-A2 molecules were immunized with two selected mutant peptides and analyzed. Although the peptide comprising mutation T315I did not elicit immune responses, two specific TCRs against the peptide comprising mutation E255V (ABL-E255V) were isolated from ABabDII mice. The T9141 TCR exhibiting a superior avidity was further analyzed for off-target toxicity. As no allo- and cross-reactivities were detected, T9141 was constructed to express minimal murinized human TCR constant region (T9141-mmc) as in the clinic. The expression and the functionality of T9141-mmc were comparable to T9141. Furthermore, ABL-E255V was demonstrated to be endogenously processed and presented by the ABL-minigene-E255V-transduced cancer cell lines. Taking a step forward, we introduced the point mutation E255V into Ph+ CML cell lines to simulate the antigen expression of blast cells in CML patients. Although no T cell responses against the genome-edited BV173 cells were found, detectable T cell responses against the genome-edited K562-A2 cells were observed, suggesting that the induced T cell responses varied with the BCR-ABL expression level in CML cell lines. Accordingly, the potency of T9141 could differ among CML patients. Therefore, it is recommended to analyze the BCR-ABL expression level in corresponding CML patients, which should allow us to evaluate the efficacy of TCR gene therapy with T9141. Taken together, T9141 is optimal for TCR gene therapy; ABL-E255V could be a potential target.

This dissertation combines insights from the Spanish labour market, the impact of the economic crisis and the lifelines of Colombian and Ecuadorian-born (ir)regular migrants between 2003 and 2015. The concept of in-between serves to better understand the migrants as vital actors, finding, creating and (re)shaping social spaces of (in)formal reaction, resistance and survival to changing conditions over time. The connections between the dimensions of labour market access, (in)formality and legal status are analysed by exploring how these structures influence the work and status trajectories of migrants. The findings question the conventional wisdom that secure legal status is the key factor for migrants to achieve a living. The results showed how migrants’ agency can surpass obstacles. Migrants act in-between spaces of in/formality and il/legality to secure their legal status through job contracts. Circular labour engagement and multiple job or site engagement are effective ways for migrants to confront the economic crisis and use their agency to shape in-between spaces and sustain their livelihood in Spain.

Winter windstorms are among the most severe natural hazards in Europe and are frequently the cause of enormous economic losses. Therefore, it is not surprising that studies on windstorms often revolve around their potential insured losses, return values, or overall severity. Each of these measures is an important indicator for decision-makers to understand the potential impacts of current and future windstorm events. Especially now, as evidence of advancing climate change becomes more apparent. A much less researched but equally informative topic in this context is the characteristics of windstorms. Duration, size, and intensity are only a few examples of windstorm characteristics that are not only statistical properties of the event but also measures of severity themselves. In this dissertation, we study multiple European winter windstorm characteristics with the goal of identifying and understanding key parameters determining these characteristics, quantifying their impact, and investigating potential trends. Using the new ERA5 reanalysis product of the European Centre for Medium-Range Weather Forecasts, windstorms are tracked and matched to a parent cyclone. A set of windstorm characteristics is designed based on commonly evaluated characteristics from the windstorm and natural hazard community. Based on these characteristics, a set of windstorms is partitioned for the purpose of constructing objective windstorm classes, not only for further evaluation but also in an effort to create universally applicable windstorm classes for a wide range of end-users. In the process, we introduce our newly developed quasi-supervised k-means (QSKM), a semi-supervised clustering technique for grouping windstorm events with respect to a catalog of historically severe windstorm events. QSKM constructs three different windstorm classes, one of which closely resembles the windstorm catalog in its inherent characteristics. In a comprehensive evaluation of the constructed classes, we show that large events with high wind speeds and an exceptionally long lifetime often originate in the West Atlantic near the US east coast, intensify over the mid and eastern parts of the Atlantic, and usually hit Central or North Europe. Their occurrence can be associated with a strong jet stream and a deep parent cyclone. Affected areas experience strong wind gusts between 15-20 hours, with peak wind speeds in the early 10 hours of occurrence. Comparable weaker and smaller events are found in the Mediterranean region. Those events often develop in the East Atlantic or Mediterranean Sea where they also dissolve due to their short lifetime. However, due to their slow-moving character, they often affect local areas for up to 20 hours and more regardless of their short lifetime. Similar small and short events, but with high wind speeds are typical for northern Europe. These types of events usually originate in the western parts of the North Atlantic and further intensify as they travel across the open water. Although only exhibiting a third of the size of the first class of events, the core pressure of their parent cyclone can also drop below 970 hPa.

Aufgrund der pandemiebedingten Schulschließungen und der daraus resultierenden Zunahme an emotionalen und Verhaltensproblemen bei Kindern und Jugendlichen, wird die Bedeutung mentaler Gesundheit und einer positiven psychosozialen Entwicklung immer wichtiger. Wenn emotionale und Verhaltensprobleme nicht präventiv oder interventiv behandelt werden, können diese negative kurz- und langfristige Auswirkungen haben und die Wahrscheinlichkeit für internalisierende und externalisierende Störungen erhöhen sowie zu eingeschränkteren schulischen Leistungen und allgemein einer schlechteren akademischen Laufbahn führen. Da Kinder einen Großteil des Tages in der Schule verbringen, ist das Schulsetting ein bedeutsamer Ort, an dem sozial-emotionale Kompetenzen erlernt, erprobt und gefördert werden können. Diese können als protektiver Faktor dienen, um Risikofaktoren für einen negativen Entwicklungsverlauf abzumildern. Metaanalysen konnten zeigen, dass durch die Teilnahme an Schulprogrammen, basierend auf Prinzipien des sozial-emotionalen Lernens (SEL), bei Schüler*innen im Vergleich zu einer Kontrollgruppe sozial-emotionale Kompetenzen, prosoziales Verhalten, Schulleistungen sowie ein positives Selbstbild zunahmen und sich emotionale und Verhaltensprobleme reduzierten (Diekstra & Gravesteijn, 2008; Durlak et al., 2011; Sklad et al., 2012; Taylor et al., 2017). Obwohl es ein umfangreiches Angebot an schulischen Präventions- und Interventionsprogrammen gibt, mangelt es in Deutschland an theoretisch fundierten und evidenzbasierten Programmen, die den Anforderungen aus der Praxis gerecht werden. Die vorliegende kumulative Dissertation beinhaltet drei Manuskripte und zielt darauf ab, unter Berücksichtigung des Wissensstandes der Implementationsforschung, ein universell-selektives schulisches Präventionsprogramm, aufbauend auf den Erkenntnissen der entwicklungsorientierten Prävention und Positiven Psychologie, zu entwickeln. Das Programm Papilio-6bis9 für Kinder der ersten und zweiten Jahrgangsstufe soll den Übergang von einem eher informellen, spielerischen Setting (der Kindertagesstätte) in ein strukturierteres, akademisches Setting (die Grundschule) erleichtern und durch die Förderung sozial-emotionaler Kompetenzen das Risiko für emotionale und Verhaltensprobleme reduzieren. Obwohl das Bewusstsein für evidenzbasierte schulische Prävention und Intervention zunimmt, gibt es einen Mangel an flächendeckender Implementation in der Praxis. Die erste Studie befasst sich mit der Frage, welche Barrieren und welche vorliegenden sowie erwünschten Ressourcen hinsichtlich der Implementation von schulischen Präventions- und Interventionsangeboten (hier bezogen auf (Cyber-)Bullying) vom Schulpersonal wahrgenommen werden und ob sich das Schulpersonal anhand der Daten in bestimmte Typologien/Einstellungsmuster zuordnen lässt. Berücksichtigt man das Phänomen (Cyber-) Bullying als ein Ausdruck von Problemverhalten und einen Mangel an Problemlösestrategien, lassen sich die Erkenntnisse auch auf andere Bereiche der schulischen Prävention und Intervention übertragen. Mit Hilfe eines teilstrukturierten Interviewleitfadens konnten drei partizipative Fokusgruppendiskussionen durchgeführt werden (N = 21, 71% Frauen). Die Transkripte der Fokusgruppen wurden mittels einer datenbasierten, induktiven thematischen Inhaltsanalyse (Braun & Clarke, 2006) mit MAXQDA 2022 ausgewertet, wobei Codes generiert und anschließend übergeordneten Themen zugeordnet wurden. Die gewonnenen Daten liefern Hinweise auf vier Einstellungstypen (der reaktive Typ, der kollaborative Typ, der intendierende Typ und der initiative Typ), anhand derer praktische Implikationen für die Programmgestaltung und Entwicklung von individualisierbaren Fortbildungsangeboten abgeleitet werden konnten. Das zweite Manuskript zielt darauf ab, ein wissenschaftliches, theoretisch fundiertes und transparentes Vorgehen bei der Programmentwicklung und -resultierend aus den Ergebnissen der Prozessevaluation- der Adaption der Materialien zu beschreiben. Hierzu wurde mit Hilfe des Intervention Mapping Ansatzes (IMA, Bartholomew Eldredge et al., 2016) eine Serie von sechs Schritten durchlaufen: nach einer Bedarfsanalyse und der Definition des Problems, der Ursachen und der Zielgruppe wurde ein Modell der Veränderung inklusive Erläuterung der Programmziele eingeführt. Anschließend folgte eine Auswahl von evidenzbasierten Strategien und die Entwicklung von geeigneten, altersangemessenen Methoden, welche in Form eines manualisierten Programms organisiert und erprobt wurden. Nach der praktischen Testung und Überarbeitung der Methoden wurde das Programm entwickelt, gefolgt von einem Implementations- und Evaluationsplan. Basierend auf einer Stichprobe von 224 Schüler*innen der ersten Klasse (52% Mädchen, Alter M = 7.1 Jahre) wurde dann im Rahmen einer Pilotierung mit Hilfe eines kontrollierten (Wartekontroll-)Gruppen-Längsschnittdesigns mit drei Messzeitpunkten untersucht, ob die Programmteilnahme zu signifikanten Veränderungen in den Bereichen sozial-emotionale Kompetenzen, emotionale und Verhaltensprobleme, Exekutivfunktionen und der Lehrkraft-Schüler*innen-Beziehung führt. Die Ergebnisse konnten in der Interventionsgruppe positive Veränderungen in allen untersuchten Bereichen zeigen und weisen auf die generelle Programmwirksamkeit hin. Abschließend werden theoretische und praktische Implikationen sowie Limitationen erörtert und resultieren in einem Ausblick für zukünftige Forschung und praktische/gesellschaftliche Veränderungen.

Der Erwerb von guten sprachlichen und schriftsprachlichen Kompetenzen ist eine der zentralsten Entwicklungsaufgaben in der frühen Kindheit. Umfangreiche nationale wie internationale Forschungsarbeiten bestätigten wiederholt die Bedeutung einer qualitativ hochwertigen frühkindlichen Bildung für den erfolgreichen Spracherwerb. In diesem Zusammenhang gilt die sprachliche Bildung von Kindern als eine der wichtigsten Aufgaben frühkindlicher Bildungsinstitutionen. In deutschen Kindertageseinrichtungen werden typischerweise zwei unterschiedliche Ansätze sprachlicher Bildung beschrieben: die Fachkraft-gelenkte, hoch strukturierte additive Sprachförderung über zusätzliche Programme sowie die eher Kind-zentrierte, alltagsintegrierte sprachliche Bildung und Förderung. Letzterer Ansatz wurde auch verstärkt hinsichtlich seines Potentials für eine kompensatorische Förderung von Kindern mit Sprachförderbedarfen diskutiert, was einen weiteren Ansatz sprachlicher Bildung formuliert. Wie die sprachliche Bildung in der Kita-Praxis umgesetzt wird und welche Qualität frühpädagogische Fachkräfte in ihren Interaktionen mit Kindern offerieren, hängt maßgeblich von den professionellen Kompetenzen der Fachkräfte ab. Befunde aus der Lehrkräfteforschung verweisen u. a. auf die Bedeutung von Lehr-Lern-Überzeugungen und fachdidaktischem Wissen für die Unterrichtsqualität. Beide Kompetenzfacetten gelten theoretisch auch für die sprachliche Bildung in Kindertageseinrichtungen als bedeutsam, weil sie darüber informieren, wie sprachliche Lerngelegenheiten ausgewählt und umgesetzt werden. Professionelle Kompetenzen von frühpädagogischen Fachkräften sind jedoch unterforscht, wenngleich in den vergangenen Jahren eine Zunahme an Untersuchungen zu verzeichnen ist. Ein Großteil dieser Studien untersucht Lehr-Lern-Überzeugungen und fachdidaktisches Wissen in den Bildungsbereichen Mathematik und Naturwissenschaften; die Ergebnisse legen nahe, dass die Kompetenzen der Fachkräfte domänenspezifisch erfasst werden sollten. Bislang gibt es jedoch keine Untersuchungen, die Lehr-Lern-Überzeugungen im Bildungsbereich Sprache erforscht haben. Die wenigen Untersuchungen, die zum fachdidaktischen Wissen im Bereich Sprache vorgelegt wurden, setzten sich außerdem kaum mit spezifischen Wissensaspekten auseinander, die zentral für eine alltagsintegrierte sprachliche Bildung und Förderung sind. Vor diesem Hintergrund untersucht die vorliegende Dissertation in drei empirischen Studien die sprachbezogenen Lehr-Lern-Überzeugungen von frühpädagogischen Fachkräften und ihr fachdidaktisches Wissen spezifisch in der alltagsintegrierten sprachlichen Bildung und Förderung. Die erste Studie untersucht die Struktur und Determinanten von sprachbezogenen Lehr-Lern-Überzeugungen bei frühpädagogischen Fachkräften unter Verwendung eines neuentwickelten Instruments. Die Ergebnisse konfirmatorischer und explorativer Faktorenanalysen wiesen auf eine zweidimensionale Struktur der sprachbezogenen Lehr-Lern-Überzeugungen hin. Unter-schieden wurden Überzeugungen, die auf eine Unterstützung additiver Sprachförderprogramme fokussieren (additive sprachbezogene Lehr-Lern-Überzeugungen), und Überzeugungen, die auf eine alltagsintegrierte sprachliche Bildung und Förderung abzielen (alltagsintegrierte sprachbezogene Lehr-Lern-Überzeugungen). Die Facette der alltagsintegrierten sprachlichen Bildung und Förderung mit einem kompensatorischen Fokus konnte hingegen nicht als eigenständige Dimension der Lehr-Lern-Überzeugungen abgebildet werden. Es zeigten sich differenzielle Zusammenhänge zwischen den beiden ermittelten Überzeugungsfacetten und fachkraftbezogenen Strukturmerkmalen, während einrichtungsbezogene Strukturmerkmale nicht bedeutsam waren für die sprachbezogenen Lehr-Lern-Überzeugungen. Die zweite Studie nutzt die in Studie 1 etablierte Skala und untersucht, in welchem Zusammenhang sprachbezogene Lehr-Lern-Überzeugungen und die Prozessqualität in Kindertageseinrichtungen unter Berücksichtigung weiterer Strukturmerkmale stehen. Für die Erfassung bereichsspezifischer Prozessqualität kam die Sustained Shared Thinking and Emotional Well-being (SSTEW)-Skala zum Einsatz, konkret die beiden Subskalen „Unterstützung und Förderung der Sprache und Kommunikation“ und „Unterstützung des Lernens und kritischen Denkens“. Als globales Prozessmaß wurde zudem die Caregiver Interaction Scale (CIS) eingesetzt, wobei die Subskalen „Sensitivität“ und „Strenge“ den Indikator „Sensitivität in Interaktionen“ gebildet haben. Die Ergebnisse multipler Regressionsanalysen zeigten, dass additive sprachbezogene Lehr-Lern-Überzeugungen in einem signifikant negativen Zusammenhang mit dem emotionalen Klima in der Gruppe (CIS) standen, während sich ein tendenziell signifikanter Zusammenhang zwischen alltagsintegrierten sprachbezogenen Lehr-Lern-Überzeugungen und kognitiv anregenden Fachkraft-Kind-Interaktionen im Sinne des Sustained Shared Thinking fand (SSTEW-Subskala „Unterstützung des Lernens und kritischen Denkens“). Darüber hinaus waren eher einrichtungs- als fachkraftbezogene Strukturmerkmale bedeutsam für die Qualität der pädagogischen Prozesse. Die dritte Studie untersucht zwei Aspekte fachdidaktischen Wissens explorativ, die sich insbesondere im Kontext der kind- und situationsorientierten frühpädagogischen Praxis in Deutschland als relevant erweisen, da sprachliche Lerngelegenheiten spontan im Kita-Alltag aufgegriffen und genutzt werden müssen: erstens, die Sensitivität für das sprachbezogene Bildungspotential von Alltagssituationen und zweitens, die pädagogische Gestaltung einer sprachförderlichen räumlich-materiellen Umgebung. Ferner wurde geprüft, ob sich das Wissen der Fachkräfte vor dem Hintergrund ihrer Qualifikation unterscheidet. Die Daten wurden über offene Fragen in einer Onlinebefragung erhoben, inhaltsanalytisch ausgewertet und in quantifizierbare Daten überführt. Die Ergebnisse aus Studie 3 verweisen grundlegend auf ein Verbesserungspotential im Hinblick auf die Konkretisierung von relevanten Wissensbeständen bei der Nutzung von Alltagssituationen und pädagogischen Räumen in der sprachlichen Bildung. Die Varianzaufklärung durch die Qualifikation der Fachkräfte fiel insgesamt gering aus. Zusammenfassend leisten die Ergebnisse der drei empirischen Studien einen wichtigen Beitrag für den Diskurs über professionelle Kompetenzen von frühpädagogischen Fachkräften in der sprachlichen Bildung. Implikationen für die frühpädagogische Forschung, Fachpraxis und Bildungspolitik werden diskutiert.

Im Rahmen der vorliegenden Arbeit wurden die Defektstrukturen von CaO/Mo(001) und SiO2/Ru(0001) und die Hydroxylierung des SiO2/Ru(0001) unter Verwendung der Elektronensprinresonanz Spektroskopie (ESR) und der hochaufgelösten Elektronenenergieverlustspektroskopie (HREELS) untersucht. Es konnte für beide Systeme gezeigt werden, dass die Strukturdefekte stark von Details in der Präparation abhängig sind. Für das SiO2/Ru(0001) System wurde gezeigt, dass die kristalline und die amorphe Form des Films zwar durch die Beugung niederenergetischer Elektronen (LEED), aber nicht aufgrund von Schwingungssignalen unterschieden werden können. Außerdem konnte die Substratbedeckung und Defekte wie zusätzliche Siliziumpartikel oder Anteile, die nur mit einer Monolage bedeckt sind, hervorragend, durch Kombination aus den HREEL Experimenten und theoretisch berechneten Daten charakterisiert werden. Die detektierten HREEL Spektren lassen auf unterschiedliche Hydroxylierungsmechanismen für defektreiche und defektarme SiO2 Filme schließen. Elektronenspinresonanz Spektroskopie Messungen zusammen mit Untersuchungen aus einer Kombination von Infrarot-Reflexions-Absorptions-Spektroskopie (IRAS) und Massenspektrometrie zeigten, dass eine Reihe an reaktiven Spezies während des elektronenunterstützten Hydroxylierungsprozess entstehen, die unterschiedlichen Hydroxylierungsmechanismen denkbar machen. Die Untersuchungen des CaO/Mo(001) Systems zeigen, dass eine geringere Wachstumsgeschwindigkeit eine komplexere Defektstruktur liefert. Die Molybdändiffusion aus dem Substrat in den Film wird bei hoher Präparationstemperatur und geringerer Wachstumsrate des CaO Films begünstigt. Es werden unterschiedliche paramagnetische Strukturdefekte gefunden, die im Volumen der Filme lokalisiert sind. Darüber hinaus lassen sich weitere paramagnetische Spezies detektieren, die im Zusammenhang mit dem Auftreten der paramagnetischen Molybdänspezies stehen und damit zur damit zur Änderung der elektronischen Struktur beitragen.

Lipids have accompanied the emergence of life on Earth. Their tendency to form spherical assemblies in water afforded the separation of organisms from their environment while still allowing controlled exchange of substances between the inside and outside. Lipids enable cellular compartmentalization, modulate membrane proteins, and are involved in intra- and intercellular signaling. The multitude of biological functions is reflected in a tremendous structural diversity, which involves the frequent occurrence of isomers with very specific biological roles. Although highly relevant from a biological perspective, many lipid isomers cannot be distinguished by state-of-the-art mass spectrometry-based analytical techniques.

This work explores the potential of coupling mass spectrometry with infrared spectroscopy to analyze lipid isomers and study lipid fragmentation mechanisms. Infrared spectroscopy adds a structural dimension to the mass spectrometric analysis and previously yielded promising results for other biomolecules. We recorded the first high-resolution infrared spectra of ionized lipids and glycolipids using helium nanodroplets as a cryogenic spectroscopic matrix. Isomeric glycolipids were found to be unambiguously distinguishable based on their diagnostic spectroscopic fingerprints. The high resolution and sensitivity of the technique enabled the relative quantification of low-abundant glycolipid isomers in biological samples by spectral deconvolution. A similar approach was used to analyze double bond isomers in lipids extracted from cancer cells, which revealed significant differences between cancer types. The position and geometry of C C bonds in sphingolipids and fatty acids were rendered visible by amines, which interact with the C C bond and induce diagnostic vibrations. Furthermore, infrared spectroscopy was employed in combination with computational chemistry to gain fundamental understanding of lipid fragmentation in tandem mass spectrometry. A key fragmentation mechanism used for the structural analysis of glycerolipids was thus unveiled and found to occur with high regioselectivity. In addition, unknown fragmentation pathways of vitamin E derivatives were identified by spectroscopy-based assignment of fragment structures. Overall, the coupling of mass spectrometry and infrared spectroscopy has proven to be a powerful approach to study lipid fragmentation mechanisms and to identify biologically relevant lipid isomers from minute sample amounts. The technique is expected to drive important advances in lipid analysis in the near future.

Cancer is one of the major public health issues, causing several million losses every year. Although anti-cancer drugs have been developed and are globally administered, mild to severe side effects are known to occur during treatment. Computer-aided drug discovery has become a cornerstone for unveiling treatments of existing as well as emerging diseases. Computational methods aim to not only speed up the drug design process, but to also reduce time-consuming, costly experiments, as well as in vivo animal testing. In this context, over the last decade especially, deep learning began to play a prominent role in the prediction of molecular activity, property and toxicity. However, there are still major challenges when applying deep learning models in drug discovery. Those challenges include data scarcity for physicochemical tasks, the difficulty of interpreting the prediction made by deep neural networks, and the necessity of open-source and robust workflows to ensure reproducibility and reusability. In this thesis, after reviewing the state-of-the-art in deep learning applied to virtual screening, we address the previously mentioned challenges as follows: Regarding data scarcity in the context of deep learning applied to small molecules, we developed data augmentation techniques based on the SMILES encoding. This linear string notation enumerates the atoms present in a compound by following a path along the molecule graph. Multiplicity of SMILES for a single compound can be reached by traversing the graph using different paths. We applied the developed augmentation techniques to three different deep learning models, including convolutional and recurrent neural networks, and to four property and activity data sets. The results show that augmentation improves the model accuracy independently of the deep learning model, as well as of the data set size. Moreover, we computed the uncertainty of a model by using augmentation at inference time. In this regard, we have shown that the more confident the model is in its prediction, the smaller is the error, implying that a given prediction can be trusted and is close to the target value. The software and associated documentation allows making predictions for novel compounds and have been made freely available. Trusting predictions blindly from algorithms may have serious consequences in areas of healthcare. In this context, better understanding how a neural network classifies a compound based on its input features is highly beneficial by helping to de-risk and optimize compounds. In this research project, we decomposed the inner layers of a deep neural network to identify the toxic substructures, the toxicophores, of a compound that led to the toxicity classification. Using molecular fingerprints —vectors that indicate the presence or absence of a particular atomic environment —we were able to map a toxicity score to each of these substructures. Moreover, we developed a method to visualize in 2D the toxicophores within a compound, the so- called cytotoxicity maps, which could be of great use to medicinal chemists in identifying ways to modify molecules to eliminate toxicity. Not only does the deep learning model reach state-of-the-art results, but the identified toxicophores confirm known toxic substructures, as well as expand new potential candidates. In order to speed up the drug discovery process, the accessibility to robust and modular workflows is extremely advantageous. In this context, the fully open-source TeachOpenCADD project was developed. Significant tasks in both cheminformatics and bioinformatics are implemented in a pedagogical fashion, allowing the material to be used for teaching as well as the starting point for novel research. In this framework, a special pipeline is dedicated to kinases, a family of proteins which are known to be involved in diseases such as cancer. The aim is to gain insights into off-targets, i.e. proteins that are unintentionally affected by a compound, and that can cause adverse effects in treatments. Four measures of kinase similarity are implemented, taking into account sequence, and structural information, as well as protein-ligand interaction, and ligand profiling data. The workflow provides clustering of a set of kinases, which can be further analyzed to understand off-target effects of inhibitors. Results show that analyzing kinases using several perspectives is crucial for the insight into off-target prediction, and gaining a global perspective of the kinome. These novel methods can be exploited in the discovery of new drugs, and more specifically diseases involved in the dysregulation of kinases, such as cancer.

Drug development is a long, expensive, and iterative process with a high failure rate, while patients wait impatiently for treatment. Kinases are one of the main drug targets studied for the last decades to combat cancer, the second leading cause of death worldwide. These efforts resulted in a plethora of structural, chemical, and pharmacological kinase data, which are collected in the KLIFS database. In this thesis, we apply ideas from structural cheminformatics to the rich KLIFS dataset, aiming to provide computational tools that speed up the complex drug discovery process. We focus on methods for target prediction and fragment-based drug design that study characteristics of kinase binding sites (also called pockets).

First, we introduce the concept of computational target prediction, which is vital in the early stages of drug discovery. This approach identifies biological entities such as proteins that may (i) modulate a disease of interest (targets or on-targets) or (ii) cause unwanted side effects due to their similarity to on-targets (off-targets). We focus on the research field of binding site comparison, which lacked a freely available and efficient tool to determine similarities between the highly conserved kinase pockets. We fill this gap with the novel method KiSSim, which encodes and compares spatial and physicochemical pocket properties for all kinases (kinome) that are structurally resolved. We study kinase similarities in the form of kinome-wide phylogenetic trees and detect expected and unexpected off-targets. To allow multiple perspectives on kinase similarity, we propose an automated and production-ready pipeline; user-defined kinases can be inspected complementarily based on their pocket sequence and structure (KiSSim), pocket-ligand interactions, and ligand profiles.

Second, we introduce the concept of fragment-based drug design, which is useful to identify and optimize active and promising molecules (hits and leads). This approach identifies low-molecular-weight molecules (fragments) that bind weakly to a target and are then grown into larger high-affinity drug-like molecules. With the novel method KinFragLib, we provide a fragment dataset for kinases (fragment library) by viewing kinase inhibitors as combinations of fragments. Kinases have a highly conserved pocket with well-defined regions (subpockets); based on the subpockets that they occupy, we fragment kinase inhibitors in experimentally resolved protein-ligand complexes. The resulting dataset is used to generate novel kinase-focused molecules that are recombinations of the previously fragmented kinase inhibitors while considering their subpockets. The KinFragLib and KiSSim methods are published as freely available Python tools.

Third, we advocate for open and reproducible research that applies FAIR principles ---data and software shall be findable, accessible, interoperable, and reusable--- and software best practices. In this context, we present the TeachOpenCADD platform that contains pipelines for computer-aided drug design. We use open source software and data to demonstrate ligand-based applications from cheminformatics and structure-based applications from structural bioinformatics. To emphasize the importance of FAIR data, we dedicate several topics to accessing life science databases such as ChEMBL, PubChem, PDB, and KLIFS. These pipelines are not only useful to novices in the field to gain domain-specific skills but can also serve as a starting point to study research questions. Furthermore, we show an example of how to build a stand-alone tool that formalizes reoccurring project-overarching tasks: OpenCADD-KLIFS offers a clean and user-friendly Python API to interact with the KLIFS database and fetch different kinase data types. This tool has been used in this thesis and beyond to support kinase-focused projects.

We believe that the FAIR-based methods, tools, and pipelines presented in this thesis (i) are valuable additions to the toolbox for kinase research, (ii) provide relevant material for scientists who seek to learn, teach, or answer questions in the realm of computer-aided drug design, and (iii) contribute to making drug discovery more efficient, reproducible, and reusable.

Der Begriff Politische Religion sowie Entsprechungen in anderen Sprachräumen erfreuen sich seit über einem Vierteljahrhundert einer wachsenden internationalen Popularität in der wissen-schaftlichen und populärwissenschaftlichen, aber auch tagespolitischen Medienlandschaft. Dies ist mitunter der 1986 veröffentlichten englischen Übersetzung und der 1993 herausgegebenen Neuauflage der Schrift Die politischen Religionen (1938) des österreichischen Politologen und Philosophen Eric Voegelin (1901-1985) und der breiten Rezeption seiner gleichnamigen Theo-rie zu verschulden, die er zur Wesensbeschreibung und Interpretation totalitärer Herrschafts-formen des 20. Jahrhunderts, wie etwa des Kommunismus und Nationalsozialismus, heranzog. Seit dieser Neubelebung in den 1990er Jahren wurde der Begriff als politisch-religiöses Inter-pretationsmodell interdisziplinär in der Forschungslandschaft in zahlreichen wissenschaftlichen Studien wieder aufgegriffen, die im Gros auf Voegelin als Galionsfigur des Theorems Politi-sche Religion und dessen Publikation als Grundlagen- und Referenzschrift rekurrieren, obwohl er weder Begründer noch einziger zeitgenössischer Vertreter dieses Ansatzes war und sich spä-terhin von dieser kontroversen Terminologie distanzierte. Es ist vermutlich dieser seit den 1990er Jahren anhaltenden Voegelin-Fixierung geschuldet, dass bisher nur wenige Forschende den Blick auf frühe Verwendungen des Begriffs Politische Religion gerichtet haben, dessen Wurzeln bis ins 16. Jahrhundert zurückverfolgt werden kön-nen. Diesem Mangel wendet sich die vorliegende Studie mit dem Ziel einer begriffsgeschichtli-chen Annäherung an die frühen Verwendungen des Begriffs Politische Religion im Zeitraum vom 16. bis zum 19. Jahrhundert zu. Da sich allein im deutschsprachigen Raum zahlreiche Verwendungsbelege finden, wird der Fokus auf deutschsprachige Publikationen gelegt. Punk-tuell soll an ausgewählten Stellen auch auf Quellen aus anderen Sprachräumen (zum Beispiel Latein, Französisch und Englisch) verwiesen und ein translingualer Ausblick gewagt werden. Zur Erschließung des Quellenmaterials bedient sich die Studie einer Verflechtung methodischer Ansätze aus den Bereichen der Historischen Semantik. Dabei sollen u. a. folgende Untersu-chungsfragen in den Vordergrund gestellt werden: In welchen historischen, politischen oder religiösen Kontexten tauchen die ersten belegbaren Verwendungen im 16. und 17. Jahrhundert auf und welchem sozialen wie religiösen Umfeld ist die frühe Autorschaft zuzuordnen? Wel-chen Wandel durchlief der Begriff im Untersuchungszeitraum? Welche Gemeinsamkeiten und Unterschiede bestehen zwischen dem frühneuzeitlichen Begriffsverständnis und einer Verwen-dung als Analyseinstrument zur Deutung moderner Herrschaftsformen im 20. und 21. Jahrhundert? Die Historisierung des Begriffs und seine Einbettung in den diskursgeschicht-lichen Kontext des Religionsbegriffs sollen einen Überblick zur Geschichte des Begriffs Politi-sche Religion auf der Grundlage eines bisher unerschlossenen Quellenmaterials bieten und die unterschiedlichen Begriffsbedeutungen sowie die mit ihnen transportierten Intentionen im Laufe der Jahrhunderte und im Wandel eines bis heute kaum greifbaren Religionsbegriffs aufzeigen.

Sensory neurons of the vagus nerve monitor distention, stretch and nutrients in the gastrointestinal tract, and major efforts are underway to assign physiological functions to the many distinct subtypes of vagal sensory neurons. Here, we used genetically guided anatomical tracing, optogenetics and electrophysiology to identify and characterize three vagal sensory neuronal subtypes expressing Prox2 and Runx3 in mice. We show that these neuronal subtypes function as putative mechanoreceptors. They innervate the esophagus and stomach where they display regionalized innervation patterns, as well as other organs. The electrophysiological analysis of Prox2/Runx3 neurons innervating the esophagus showed that they are all low threshold mechanoreceptors, but possess different adaptation properties. Lastly, genetic ablation of Prox2 and Runx3 neurons demonstrated their essential roles for esophageal peristalsis and swallowing in freely behaving mice. Our work reveals the identity and function of the vagal neurons that provide mechanosensory feedback from the esophagus to the brain, and might lead to better understanding and treatment of esophageal motility disorders.

To extend current charge-based electronics by new features and functionalities, the electron spin, as a new degree of freedom, is likely to play a major role in future information technology. Devices using such spin-based electronics (spintronics), for example magnetic random-access memories, are about to enter the market. To be competitive with other information carriers, it is required to push the bandwidth of the elementary spintronic operations to the terahertz (THz) frequency range.

This thesis addresses central open questions regarding ultrafast spin transport in prototypical FjN thin-film stacks. Is ultrafast spin transport mediated by magnons as universal as indicated by previous modelling? What impact does the F/N interface between F and N have on the ultrafast spin-to-charge current conversion (S2C)? How can we exploit spintronic features for new functionalities of spintronic THz emitters (STEs)? By studying spin current dynamics on their natural timescale, one may find new interesting effects or push existing concepts to THz frequencies, which might advance future spintronic applications to work at higher clock rates.

To study ultrafast spin transport in FjN bilayers, we excite them with femtosecond laser pulses. Following absorption of the pulse, a spin current in F is launched and converted into a transverse charge current in N and/or F, giving rise to the emission of a THz electromagnetic pulse. Using this approach, along with an analysis based on symmetry arguments and modeling, the following insights are gained:

First, depending on the conductivity of F, spin currents can be carried by either (i) conduction electrons or (ii) magnons. Remarkably, in the half-metallic ferrimagnet Fe3O4 we observe the coexistence of these two spin transport types and disentangle them based on their distinctly different ultrafast dynamics. Our results also indicate that the ultrafast SSE spin current is localized close to the F/Pt interface and its ultrafast dynamics are determined by the relaxation dynamics of the electrons in the Pt layer.

Second, interfaces of metallic heterostructures are known to have a marked impact on the S2C process. We study thin metal lms of a ferromagnetic layer F and nonmagnetic layer N with strong and weak spin-orbit coupling. Varying the interface composition allows us to drastically change the amplitude and even invert the polarity of the THz charge current. Symmetry arguments and first-principles calculations strongly suggest that the interfacial S2C arises from skew scattering of spin-polarized electrons at interface imperfections.

Third, we add a functionality to the STE and modulate the polarization of broadband THz electric field pulses at tens of kHz by time-dependent external magnetic field with a contrast exceeding 99 %.

In conclusion, THz emission spectroscopy is a powerful tool to explore and exploit spintronic effects in the ultrafast regime, which will lay the cornerstone for spintronics at THz frequencies.

Molecular Dynamics simulations provide a powerful tool to study biomolecular systems with atomistic detail. The key to better understand the function and behaviour of these molecules can often be found in their structural variability. Simulations can help to expose this information that is otherwise experimentally hard or impossible to attain. This work covers two application examples for which a sampling and a characterisation of the conformational ensemble could reveal the structural basis to answer a topical research question. For the fungal toxin phalloidin—a small bicyclic peptide—observed product ratios in different cyclisation reactions could be rationalised by assessing the conformational pre-organisation of precursor fragments. For the C-type lectin receptor langerin, conformational changes induced by different side-chain protonations could deliver an explanation of the pH-dependency in the protein’s calcium-binding. The investigations were accompanied by the continued development of a density-based clustering protocol into a respective software package, which is generally well applicable for the use case of extracting conformational states from Molecular Dynamics data.

The heart is the first functional organ to form during vertebrate development and it is evolutionarily conserved across species. It is crucial for the proper delivering of essential nutrients and oxygen throughout the embryo's body. Its development is complex and requires fine-tuning processes at levels involving growth, differentiation, and morphogenesis. First, a linear heart tube is formed, followed by cardiac looping, chamber formation, and maturation. As for many organs, the heart arises from a simple epithelium with planar polarity properties. The genetic and molecular programs involved in heart formation have been studied for a long time. However, besides the genetic and cellular contributions to heart formation, little is known about the molecular and cellular components involved in generating tissue and tension forces required in heart morphogenesis. Embryonic heart tube remodeling requires coordination of actomyosin-dependent tissue forces fundamental to the emergence of cardiac chambers and looped heart. It has been established that cardiac chamber remodeling is coordinated through tissue-scale polarization of actomyosin. Here, using zebrafish as a model, I describe the role of actomyosin in generating and distributing the tension forces necessary across the ventricular myocardium during cardiac looping and chamber formation. I describe the spatiotemporal distribution of phosphorylated myosin during embryonic heart formation. A mathematical model was generated to demonstrate that the tissue-scale supracellular polarization of actomyosin within the myocardial epithelium is essential for heart formation. The mathematical model serves as a predictive tool of cardiac looping and chamber formation and supports its dependence on the proper actomyosin distribution. Examining the molecular mechanisms governing the actomyosin activity along the heart tube, I demonstrate that both Rho-associated Protein Kinase 2a (Rock2a) and cardiac-specific Myosin Light Chain Kinase 3 (Mylk3) regulate the actomyosin-based tissue forces through the phosphorylation state of the Myosin Regulatory Light Chain (MRLC). I show that the preferential basal activity of Mylk3 and the apical activity of Rock2a mediate the proper levels of phosphorylated myosin (pMyo) and its polarized distribution along the apicobasal axis within the myocardium. I propose that the antagonistic force-generating activities of Mylk3 and Rock2a facilitate mechano-molecular control of heart tube morphogenesis. Moreover, I show Mylk3 and Rock2a are under the genetic control of Planar Cell Polarity signaling, identifying Mylk3 as a novel tissue-specific effector, downstream of the Vangl2 branch of this signaling pathway. Altogether, these findings describe for the first time a mechano-molecular mechanism necessary for proper looping and chamber formation during heart development.

This work is focused on the development of new microscopy-based analysis methods with single-entity resolution and high-throughput capabilities from the cellular to the molecular level to study biomembrane-associated interactions. Currently, there is a variety of methods available for obtaining quantitative information on cellular and molecular responses to external stimuli, but many of them lack either high sensitivity or high throughput. Yet, the combination of both aspects is critical for studying the weak but often complex and multivalent interactions at the interface of biological mem-branes. These interactions include binding of pathogens such as some viruses (e.g., influenza A virus, herpes simplex virus, and SARS-CoV-2), transmembrane signaling such as ligand-based oli-gomerization processes, and transduction of mechanical forces acting on cells. The goal of this work was to overcome the shortcomings of current methods by developing and es-tablishing new methods with unprecedented levels of automation, sensitivity, and parallelization. All methods are based on the combination of optical (video) microscopy followed by highly refined data analysis to study single cellular and molecular events, allowing the detection of rare events and the identification and quantification of cellular and molecular populations that would remain hidden in ensemble-averaging approaches. This work comprises four different projects. At the cellular level, two methods have been developed for single-cell segmentation and cell-by-cell readout of fluorescence reporter systems, mainly to study binding and inhibition of binding of viruses to host cells. The method developed in the first pro-ject features a high degree of automation and automatic estimation of sufficient analysis parameters (background threshold, segmentation sensitivity, and fluorescence cutoff) to reduce the manual ef-fort required for the analysis of cell-based infection assays. This method has been used for inhibition potency screening based on the IC50 value of various virus binding inhibitors. With the method used in the second project, the sensitivity of the first method is extended by providing an estimate of the number of fluorescent nanoparticles bound to the cells. The image resolution was chosen to allow many cells to be imaged in parallel. This allowed for the quantification of cell-to-cell heterogeneity of particle binding, at the expense of resolution of the individual fluorescent nanoparticles. To account for this, a new approach was developed and validated by simulations to estimate the number of fluo-rescent nanoparticles below the diffraction limit with an accuracy of about 80 to 100 %. In the third project, an approach for the analysis and refinement of two-dimensional single-particle tracking ex-periments was presented. It focused on the quality assessment of the derived tracks by providing a guide for the selection of an appropriate maximal linking distance. This tracking approach was used in the fourth project to quantify small molecule responses to hydrodynamic shear forces with sub-nm resolution. Here, the combination of TIRF microscopy, microfluidics, and single particle tracking enabled the development of a new single molecule force spectroscopy method with high resolution and parallelization capabilities. This method was validated by quantifying the mechanical response of well-defined PEG linkers and subsequently used to study the energy barriers of dissociation of mul-tivalent biotin-NeutrAvidin complexes under low (~ 1.5 to 12 pN) static forces. In summary, with this work, the repertoire of appropriate methods for high-throughput investigation of the properties and interactions of cells, nanoparticles, and molecules at single resolution is expand-ed. In the future, the methods developed here will be used to screen for additional virus binding inhib-itors, to study the oligomerization of membrane receptors on cells and model membranes, and to quantify the mechanical response of force-bearing proteins and ligand-receptor complexes under low force conditions.