Refine
Has Fulltext
- yes (223)
Is part of the Bibliography
- yes (223)
Year of publication
- 2021 (223) (remove)
Document Type
- Doctoral Thesis (223) (remove)
Language
- English (223) (remove)
Keywords
- Supramolekulare Chemie (6)
- Fluoreszenzmikroskopie (5)
- Aggregation (4)
- Selbstorganisation (4)
- Biomaterial (3)
- Caenorhabditis elegans (3)
- Konjugierte Polymere (3)
- Neisseria gonorrhoeae (3)
- Organische Chemie (3)
- cancer (3)
- ARPES (2)
- Biradikal (2)
- Chlamydia trachomatis (2)
- Chromatin (2)
- Click-Chemie (2)
- DNA repair (2)
- Evolution (2)
- Expansionsmikroskopie (2)
- Extrazelluläre Matrix (2)
- Ferroptosis (2)
- Fotokatalyse (2)
- Furylborane (2)
- GPCR (2)
- Genregulation (2)
- HPLC (2)
- HUWE1 (2)
- Heterocyclische Carbene <-N> (2)
- Hydrogel (2)
- Induzierte pluripotente Stammzelle (2)
- Kognition (2)
- Kombinatorik (2)
- Lernen (2)
- MYC (2)
- MYCN (2)
- Megakaryozyt (2)
- Melanom (2)
- Naphthylisochinolinalkaloide (2)
- Neisseria meningitidis (2)
- Neuroblastom (2)
- Operations Management (2)
- Parity Anomaly (2)
- Perylenderivate (2)
- Phonologie (2)
- Polycyclische Aromaten (2)
- Polymere (2)
- Positronen-Emissions-Tomografie (2)
- Rhodium (2)
- Rutheniumkomplexe (2)
- Self-assembly (2)
- Silizium-Boraustausch (2)
- Spectroscopy (2)
- Sphingolipide (2)
- Stammzelle (2)
- Thrombozyt (2)
- Tissue Engineering (2)
- Topological Insulators (2)
- Topologie (2)
- Transcription (2)
- TrkB (2)
- Trypanosoma brucei (2)
- Ubiquitin (2)
- Virtuelle Realität (2)
- Wasser (2)
- Zeitreihenanalyse (2)
- Zellskelett (2)
- Zelltod (2)
- Zweisprachigkeit (2)
- cell wall (2)
- climate change (2)
- extracellular matrix (2)
- habitat (2)
- host-pathogen interaction (2)
- neuroblastoma (2)
- neuropathy (2)
- optimization (2)
- regulation (2)
- sphingolipids (2)
- 1458-1463 (1)
- 177Lu-OPS201 (1)
- 3D models (1)
- 3D tissue model (1)
- 3D-Druck (1)
- 3D-Gewebemodell (1)
- 3D-druck (1)
- 5'-O-Methyldioncophylline D (1)
- 5`-UTR (1)
- 68Ga-OPS202 (1)
- 7-Dehydrocholesterol (1)
- 7T (1)
- ACC (1)
- ADGRL3 (1)
- ADHD (1)
- AI (1)
- ALS (1)
- ARIMA (1)
- ATGL (1)
- ATLAS <Teilchendetektor> (1)
- Abbildungseigenschaften (1)
- Acetylation (1)
- Acute myeloid leukemia (AML) (1)
- AdS-CFT-Korrespondenz (1)
- Adhesion GPCR (1)
- Adipose (1)
- Adipose-Derived Stromal/Stem Cells (1)
- Adrenalin (1)
- Adrenokortikales Karzinom (1)
- Affect regulation (1)
- Affekt (1)
- Agarose (1)
- Aggregat <Chemie> (1)
- Aggression (1)
- Aggressive Driving (1)
- Agrarumweltmaßnahmen (1)
- Airway epithelia (1)
- Albrecht Achilles (1)
- Algebraische Zahlentheorie (1)
- Algorithmische Geometrie (1)
- Algorithmus (1)
- Alkaloid (1)
- Alkaloide (1)
- Aluminium (1)
- Aluminiumhydridderivate (1)
- Alzheimerkrankheit (1)
- Amerikanisches Englisch (1)
- Amino Acids (1)
- Aminosäuren (1)
- Anacardic acid derivatives (1)
- Anacardsäurederivate (1)
- Ancistrocladaceae (1)
- Ancistrocladus (1)
- Ancistrolikokine E3 (1)
- Angle-resolved Photoemission Spectroscopy (1)
- Angst (1)
- Anomalie (1)
- Antagonismus (1)
- Antarctica (1)
- Anthropocene (1)
- Anti-infectious activity (1)
- Antiausterity activity (1)
- Antibiotikum (1)
- Antibody (1)
- Antioxidantien (1)
- Aortenaneurysma (1)
- Aquaporin (1)
- Arbeitsteilung (1)
- Arid biomes (1)
- Aromatizität (1)
- Artenvielfalt (1)
- Artesunate (1)
- Artificial photosynthesis (1)
- Aspergillose (1)
- Aspergillosis (1)
- Aspergillus fumigatus (1)
- Audiovisuelle Medien (1)
- Aufmerksamkeit (1)
- Aufmerksamkeitsdefizit-Syndrom (1)
- Augmented Lagrangian (1)
- Aurora-A (1)
- Aussterbedynamik (1)
- Auto-Scaling (1)
- Autoantikörper (1)
- Autophagie (1)
- Autoradiographie (1)
- Außerschulische Bildung (1)
- Avatar <Informatik> (1)
- B cells (1)
- BDNF (1)
- BN compounds (1)
- BP compounds (1)
- BRCA1 (1)
- BTB domain (1)
- Bacillus subtilis (1)
- Bahnung (1)
- Bakterienzellwand (1)
- Basal Ganglia (1)
- Basalganglien (1)
- Baseline Constrained LAMBDA (1)
- Bavarian War (1)
- Bayern (1)
- Behavior Change (1)
- Belyi map (1)
- Belyi-Funktionen (1)
- Benchmarking (1)
- Berechnungskomplexität (1)
- Beschaffung (1)
- Beschichtung (1)
- Bestrahlung (1)
- Beweissystem (1)
- Biene <Gattung> (1)
- Bienen (1)
- Bildanalyse (1)
- Bildgebendes Verfahren (1)
- Bildqualität (1)
- Bilinear differential games (1)
- Bilingualism (1)
- Biodistribution (1)
- Biodiversität (1)
- Biogenese (1)
- Biologie (1)
- Bioluminescence resonance energy transfer (1)
- Bioprinting (1)
- Bioreactor (1)
- Bioreaktor (1)
- Biradicals (1)
- Bitopic Ligands (1)
- Bitopische Liganden (1)
- Blickbewegung (1)
- Blickinteraktion (1)
- Blütenpflanzen (1)
- Bor (1)
- Bor-Phosphor-Verbindungen (1)
- Bor-Stickstoff-Verbindungen (1)
- Borazin (1)
- Bordetella (1)
- Bororganische Verbindungen (1)
- Borverbindungen (1)
- Borylation (1)
- Borylierung (1)
- Brain (1)
- Brain-derived neurotrophic factor (1)
- Bundesrepublik Deutschland - Finanzagentur (1)
- B–C coupling (1)
- B–C-Kupplung (1)
- C-Cl (1)
- C-F (1)
- C-H (1)
- C. elegans (1)
- CCR4 (1)
- CD28 (1)
- CD28-SA (1)
- CDK4 Inhibitor (1)
- CDK4 inhibitor (1)
- CIDP (1)
- CMT1A (1)
- CSIDH (1)
- Calciumkanal (1)
- Camponotus rufipes (1)
- Candida albicans (1)
- Capacity Management (1)
- Carbene (1)
- Cardiac (1)
- Cardinality Constraints (1)
- Cardiomyocyte (1)
- Cartilage (1)
- Cartilage Tissue Engineering (1)
- Cataglyphis (1)
- Cayley graph (1)
- Ccr4-Not (1)
- Cdu1 (1)
- Cell-Assisted Lipotransfer (1)
- Ceramide (1)
- ChR2 (1)
- Channelrhodopsinen (1)
- Charcot-Marie-Tooth 1A (1)
- Charge-Transfer (1)
- Charged Aerosol Detection (1)
- Chemische Reinheit (1)
- Chemotaxis (1)
- Chern Insulator (1)
- Chewing Gum (1)
- Children (1)
- Chimeric antigen receptor (CAR) (1)
- Chimpanzee (1)
- Chiral Anomaly (1)
- Chirality (1)
- Chirality Transfer (1)
- Chiralität (1)
- Chiralität <Chemie> (1)
- ChlaDUB1 (1)
- Chlamydia (1)
- Cholesterin (1)
- Cholesterol (1)
- Chromatographischer Detektor (1)
- Chromophor (1)
- Chronobiologie (1)
- Ciliary neurotrophic factor (1)
- Cloud Computing (1)
- Co-Kultur (1)
- Co-culture system (1)
- Cochlear-Implantat (1)
- Cognitive conflict (1)
- Cognitive control (1)
- Color Center (1)
- Comoé National Park (1)
- Complement system (1)
- Computational Chemistry (1)
- Computer Science education (1)
- Computersicherheit (1)
- Computertomografie (1)
- Conditioning (1)
- Congo (1)
- Conjunction analysis (1)
- Corannulene (1)
- Cortico-striatal projection neurons (1)
- Count Ulrich (1)
- Critical Phenomena (1)
- CubeSat (1)
- Cushing-Syndrom (1)
- Cuticular transpiration (1)
- Cuticular waxes (1)
- Cyclization (1)
- Cystein (1)
- Cytokine (1)
- Cytoskeleton (1)
- C–C coupling (1)
- C–C-Kupplung (1)
- C–H Aktivierung (1)
- C–H activation (1)
- DC (1)
- DHCR7 (1)
- DLS (1)
- DNA (1)
- DNS (1)
- DNS-Reparatur (1)
- DOT1 (1)
- DTI (1)
- Data Driven Operations (1)
- Data Fusion (1)
- Data-driven Operations Management (1)
- Decapping (1)
- Dectin-1 (1)
- Deeplearning (1)
- Deletion (1)
- Dendritische Zelle (1)
- Depletion (1)
- Derivsatisierung (1)
- Deutsch (1)
- Diabetes mellitus (1)
- Diagnostik (1)
- Didaktik der Informatik (1)
- Diels-Alder-Reaktion (1)
- Dienstgüte (1)
- Differential Games (1)
- Differential scanning calorimetry (1)
- Diffusionsgewichtete Magnetresonanztomografie (1)
- Dimer (1)
- Dimere (1)
- Dimerisierung (1)
- Dimerization (1)
- Dioncophylline C (1)
- Dirac System (1)
- Directed Percolation (1)
- Disjoint pair (1)
- Disordered Lattice (1)
- Donor-Acceptor Interface (1)
- Doppelresonanz (1)
- Driving Behavior (1)
- Drohne <Flugkörper> (1)
- Drosophila (1)
- Drug delivery platform (1)
- Drug resistance (1)
- Duke Ludwig the Rich (1)
- Duplikation (1)
- Dyade (1)
- E2 (1)
- ECAP (1)
- ECG-gated PET (1)
- EDTA (1)
- EEG (1)
- EPR spectroscopy (1)
- ERK-Kaskade (1)
- ERK-cascade (1)
- Educational robotics (1)
- Educational robotics competitions (1)
- Effect anticipation (1)
- Effective Action (1)
- Effektantizipation (1)
- Einkauf (1)
- Einzelmolekül-Lokalisationsmikroskopie (1)
- Einzelmolekülmikroskopie (1)
- Elector of Brandenburg (1)
- Electrical transport (1)
- Electron hydrodynamics (1)
- Elektrochemie (1)
- Elektrochromie (1)
- Elektronenkorrelation (1)
- Elektronenmikroskopie (1)
- Elektronenspinresonanz (1)
- Elektronenspinresonanzspektroskopie (1)
- Elektronentransfer (1)
- Elektronischer Transport (1)
- Elektrospinnen (1)
- Elektrostimulation (1)
- Elliptische Kurve (1)
- Emergency Medical Service System (1)
- Emotionsregulation (1)
- Emperor Friedrich III (1)
- Empirical Research (1)
- Enantiomerüberschuss (1)
- Englisch (1)
- Ensemble optimal control (1)
- Entscheidungsunterstützung (1)
- Entwicklungsländer (1)
- Entzündung (1)
- Enzyminhibitor (1)
- Eosinophiler Granulozyt (1)
- Epigenetic (1)
- Epigenetik (1)
- Ermüdungssyndrom (1)
- Error-State Extendend Kalman Filter (1)
- Erwachsener (1)
- Euler equations (1)
- Europäische Zentralbank (1)
- Expansion microscopy (1)
- Experimentelle Psychologie (1)
- Explainability (1)
- Explicit Computation (1)
- Explizite Berechnung (1)
- Expositionstherapie (1)
- Extracellular Vesicles (1)
- Exziton (1)
- FLT3 inhibitor (1)
- FMRP (1)
- FMS-like tyrosine kinase 3 (FLT3) (1)
- FRAMEWORK <Programm> (1)
- FRET (1)
- FT-IR-Spektroskopie (1)
- Fachdidaktik (1)
- Fahrerassistenzsystem (1)
- Fahrerverhalten (1)
- Farbstoff (1)
- Farbzentrum (1)
- Feature Engineering & Extraction (1)
- Feldtheorie (1)
- Female Refugees (1)
- Ferroptose (1)
- Fertilization in angiosperm (1)
- Festkörperphysik (1)
- Festkörpertheorie (1)
- Fibromyalgia (1)
- Fibromyalgie (1)
- Finite-Elemente-Methode (1)
- Finite-Volumen-Methode (1)
- Fitness (1)
- Fixpunktsatz (1)
- Flavonoide (1)
- Flippase (1)
- Flow (1)
- Fluconazol (1)
- Fluconazole (1)
- Flugbahn (1)
- Flughöhe (1)
- Flugnavigation (1)
- Flugregelung (1)
- Fluid (1)
- Fluorescence correlation spectroscopy (1)
- Fluorescence spectroscopy (1)
- Fluoreszenzliganden (1)
- Fluoreszenzspektrometer (1)
- Fluoreszenzspektroskopie (1)
- Fluorierte Arylboronate (1)
- Fluorinated Aryl Boronates (1)
- Fluss (1)
- Flüssigkristall (1)
- Folliculin (1)
- Forecasting (1)
- Formoptimierung (1)
- Formulation development (1)
- Formulierung (1)
- Formulierungsentwicklung (1)
- Fortpflanzung (1)
- Fortpflanzungsmechanismen (1)
- Fotoionisation (1)
- Fotolyse (1)
- Foxo1 (1)
- Fragiles-X-Syndrom (1)
- Freie-Elektronen-Laser (1)
- Fuchsbandwurm (1)
- Functional analyses (1)
- Functions with Primitive (1)
- Funktion von beschränkter Variation (1)
- Funktionen mit Stammfunktion (1)
- Furagieraktivität (1)
- Furanderivate (1)
- Furcht (1)
- Furylboranes (1)
- Förster Resonanz Energie Transfer (1)
- Fürstenkrieg <1458-1463> (1)
- G glycoprotein (1)
- G-Protein gekoppelte Rezeptoren (1)
- G-Protein gekoppelter Rezeptor (1)
- G-protein-coupled receptors (1)
- GWAS (1)
- Gallium (1)
- Galois-Theorie (1)
- Game mechanic (1)
- Gamification (1)
- Gasionisationsdetektor (1)
- Gaze interaction (1)
- Gefäßwand (1)
- Gehirn (1)
- Geldpolitik (1)
- Gelenkknorpel (1)
- Gen BRCA 1 (1)
- Gene Expression (1)
- Genetics (1)
- Genexpression (1)
- Genotoxicity (1)
- Genotype-phenotype relationship (1)
- Geometry (1)
- Geschichte 1458-1463 (1)
- Gestaltoptimierung (1)
- Gesundheitswesen (1)
- Glacier (1)
- Gleichmäßige Konvergenz (1)
- Global Health (1)
- Glucose Starvation (1)
- Glutathion (1)
- Glycinrezeptor (1)
- Glycophyten (1)
- Glykomodifizierung (1)
- Glykosylierung (1)
- Golgi (1)
- Gonococcal invasion (1)
- Graph (1)
- Graph spectrum (1)
- Graphenzeichnen (1)
- Gravitationsfeld (1)
- Gravitationsmodellunsicherheit (1)
- Gravity model uncertainty (1)
- Grundschulkind (1)
- GtACR1 (1)
- GvHD (1)
- H2A.Z (1)
- HECTD1 (1)
- HFpEF (1)
- HRUS (1)
- Hall Viscosity (1)
- Halophyten (1)
- Halophytes (1)
- Heart (1)
- Heart development (1)
- Heat stress (1)
- Helicobacter pylori (1)
- Herz (1)
- Herzhypertrophie (1)
- Herzmuskelzelle (1)
- Heterogenität (1)
- Heubacillus (1)
- High resolution data (1)
- High-thropughput screening (1)
- Hill numbers (1)
- Hippo pathway (1)
- Hippocampus (1)
- Hirnhaut (1)
- Histon-Methyltransferase (1)
- Histonacetyltransferase (1)
- Histone (1)
- Histone Acetylation (1)
- Histone modification (1)
- Histone variant (1)
- Hochaufgelöste Fluoreszenzmikroskopie (1)
- Hochauflösungsmikroskopie (1)
- Hochdurchsatz-Screening (1)
- Hochtemperatursupraleiter (1)
- Homicidal Chauffeur game (1)
- Hornhaut (1)
- Host-Guest-Chemistry (1)
- Human Transcriptome (1)
- Human-Centered Design (1)
- Human-pathogenic (1)
- Hyaliner Knorpel (1)
- Hyaluronsäure (1)
- Hydrodynamics (1)
- Hypercube Queueing Model (1)
- Hypoxia (1)
- Hypoxie (1)
- Höhenangst (1)
- IL-1β (1)
- IRAK2 (1)
- Ideomotor gaze control (1)
- Ideomotorik (1)
- Ideomotorische Blickkontrolle (1)
- Illustration (1)
- Iminoborane (1)
- Immunological synapse (1)
- Impurity Profiling (1)
- In-Car Interface (1)
- In-silico Modell (1)
- Infektion (1)
- Informatik (1)
- Infrarotspektroskopie (1)
- Inhibitor (1)
- Insektenstaaten (1)
- Instrumentelle Analytik (1)
- Insulin (1)
- Integer Expression (1)
- Integer circuit (1)
- Integral graph (1)
- Integralgleichung (1)
- Integration (1)
- Integration Policy (1)
- Interaktion (1)
- Interleukin (1)
- Interleukin 1-beta (1)
- Interleukin 4 (1)
- Interleukin 5 (1)
- Interleukin-4 Antagonist (1)
- Intracellular bacteria (1)
- Intrazelluläre Bakterien (1)
- Ion-Dip-Spectroscopy (1)
- Iridium-Photosensibilisator (1)
- Iron Oxide Nanoparticles (1)
- Irradiation (1)
- Ischemia (1)
- Ising model (1)
- Ising-Modell (1)
- Isoelektronisches Prinzip (1)
- Isolation (1)
- Isolierung (1)
- Isolierung <Chemie> (1)
- J-Aggregates (1)
- Jozimine A2 (1)
- Kalman-Filter (1)
- Kapazitätsplanung (1)
- Kapillarelektrophorese (1)
- Katalyse (1)
- Kation (1)
- Kaugummi (1)
- Kinetics (1)
- Kinetoplastida (1)
- Kleine Proteine (1)
- Kleinsatellit (1)
- Klimaerwärmung (1)
- Klimawandel (1)
- Klimaänderung (1)
- Knowledge encoding (1)
- Kohärenz (1)
- Kollisionsschutz (1)
- Komplement (1)
- Komplexität (1)
- Kondo-System (1)
- Konglomerat (1)
- Kongo (1)
- Konjunktionsanalyse (1)
- Konnektivitätsschätzung (1)
- Kontrollierte Wirkstofffreisetzung (1)
- Konvexe Zeichnungen (1)
- Kopienzahlvariation (1)
- Krebs <Medizin> (1)
- Krebsforschung (1)
- Kreditmarkt (1)
- Kryptologie (1)
- Kutikula (1)
- Kutikularwachs (1)
- Künstliche Intelligenz (1)
- L3 acquisition (1)
- LC3-assoziierte Phagozytose (1)
- LEED (1)
- LPS Biosynthese (1)
- Labeling (1)
- Ladungstransfer (1)
- Landnutzung (1)
- Langerhans cells (1)
- Laserspektroskopie (1)
- Latrophilin (1)
- Lebensraum (1)
- Leber-Metabolismus (1)
- Leishmania (1)
- Leistungsbewertung (1)
- Letalität (1)
- Ligand <Biochemie> (1)
- Ligand design (1)
- Linearer Operator (1)
- Liouville and transport equations (1)
- Lipid Raft (1)
- Lipid Transfer Protein (1)
- Lipid-Peroxide (1)
- Lipide (1)
- Lipolysis (1)
- Liquid Crystal (1)
- Location Optimization (1)
- Loose Coupling (1)
- Lower Critical Solution Temperature (LCST) (1)
- Ludwig der Reiche (1)
- Lung (1)
- Lunge (1)
- LysR-type (1)
- Löslichkeit (1)
- M1 Muscarinic Receptor (1)
- MIZ1 (1)
- MPGD (1)
- MS2-affinity purification and RNA-seq (1)
- Machine Learning (1)
- Macrophages (1)
- Magnetfeld (1)
- Magnetresonanztomographie (1)
- Makrophage (1)
- Mapping Properties (1)
- Markierte Verbindungen (1)
- Maschinelles Lernen (1)
- Mathematisches Modell (1)
- Mauerbiene (1)
- Mean-Field-Methode (1)
- Mechanical deformation (1)
- Mechanismus (1)
- Medium spiny neurons (1)
- Medizinische Versorgung (1)
- Megakaryocyte (1)
- Mehrkriterielle Optimierung (1)
- Mehrsprachigkeit (1)
- Melt electrowriting (1)
- Membrane receptor (1)
- Membranrezeptor (1)
- Meninges (1)
- Mensch-Maschine-Kommunikation (1)
- Merkel cell carcinoma (1)
- Merkel cell polyomavirus (1)
- Mesenchymal stem cell (1)
- Mesenchymal stromal cells (1)
- Mesenchymzelle (1)
- Mesoscopic Transport (1)
- Messenger-RNP (1)
- Metabolism (1)
- Metabolismus (1)
- Metaheuristic (1)
- Metaheuristik (1)
- Metallosupramolekulare Chemie (1)
- MgrB (1)
- Micelle (1)
- Microglia (1)
- Micromegas (1)
- Micronucleus (1)
- Microvesicle (1)
- Mitochondria (1)
- Mitochondrien (1)
- Mitochondrium (1)
- Modellgetriebene Entwicklung (1)
- Modellierung (1)
- Modifizierung (1)
- Molecular Physics (1)
- Molekularmechanik (1)
- Molekularstrahl (1)
- Molekülphysik (1)
- Monte Carlo simulations (1)
- Monte-Carlo-Simulation (1)
- Morbus Alzheimer (1)
- Motilität (1)
- Motor learning (1)
- Motorisches Lernen (1)
- Mouse Model (1)
- Multi-objective optimization (1)
- Multiproteinkomplex (1)
- Muscarinrezeptor (1)
- Muster (1)
- Mutualismus (1)
- Myatrophische Lateralsklerose (1)
- Myb-MuvB complex (1)
- Myeloid (1)
- N-Heterocyclic Carbene (1)
- N-Myc (1)
- NK cell (1)
- NK-DC cross-talk (1)
- NMR Spektroskopie (1)
- NMR spectroscopy (1)
- NMR-Spektroskopie (1)
- NP-vollständiges Problem (1)
- NRF2 (1)
- NTRK fusions (1)
- Nanogels (1)
- Nanometerbereich (1)
- Nanopartikel (1)
- Naphthyl Isoquinolines (1)
- Naphthylisoquinolin (1)
- Naphthylisoquinoline (1)
- Natural Products (1)
- Natürliche Killerzelle (1)
- Neisseria (1)
- Nervenbiopsie (1)
- Nervenultraschall (1)
- Neuroanatomie (1)
- Neuroethologie (1)
- Neuronales visuelles System (1)
- Neuropathie (1)
- Neuropeptide (1)
- Neuroprotektivum (1)
- Neuroscience (1)
- Neutronenstreuung (1)
- Neutrophil (1)
- Neutrophil granulocyte (1)
- Neutrophiler Granulozyt (1)
- Nichtgleichgewichts-Phasenübergang (1)
- Nichtlinearer Operator (1)
- Nickel (1)
- Nickelkomplexe (1)
- Niederschlag (1)
- Non-coding RNA (1)
- Non-linear optics (1)
- Nonlinear Optical Properties of Organic Materials (1)
- Notenbank (1)
- Notfallmedizin (1)
- Nozizeption (1)
- Nuclear export control (1)
- Nuclear periphery granules (1)
- Nucleic acids (1)
- Nucleinsäuren (1)
- Nucleotide excision repair (1)
- Nukleotid-Exzisions-Reparatur (1)
- OLEDs (1)
- Oberflächenphysik (1)
- Obesity (1)
- Oligomere (1)
- Onboard Software (1)
- Operatortheorie (1)
- Opiatrezeptor (1)
- Optical remote sensing data (1)
- Optimale Kontrolle (1)
- Optimierung (1)
- Optimierung / Nebenbedingung (1)
- Optimierungsproblem (1)
- Optoelektronik (1)
- Optogenetics (1)
- Optogenetik (1)
- Orakel <Informatik> (1)
- Orbit determination (1)
- Orbitbestimung (1)
- Ordnungs-Unordnungs-Umwandlung (1)
- Organisation (1)
- Organischer Halbleiter (1)
- Organisches Molekül (1)
- Organoboron (1)
- Organoboron Compounds (1)
- Osteoarthritis (1)
- Oxidation (1)
- Oxidativer Stress (1)
- Oxygen partial pressure (1)
- P-optimal (1)
- P123 (1)
- P4-ATPase (1)
- PAF1c (1)
- PBP pincer palladium complexes (1)
- PVM (1)
- Palbociclib (1)
- Pancreatic cancer (1)
- Pangenom (1)
- Paraffin (1)
- Parasit (1)
- Parasitoid (1)
- Parc National de la Comoé (1)
- Parkinson Krankheit (1)
- Parkinson's disease (1)
- Pathogenität (1)
- Pathophysiologie (1)
- Pathophysiologische Mechanismen (1)
- Pentacen (1)
- Peroxidzahl (1)
- Persistence (1)
- Persuasive Technology (1)
- Pertussis (1)
- Perylenbisdicarboximide (1)
- Perylenbisdicarboximide <Perylen-3,4:9,10-bis(dicarboximide)> (1)
- Perylenbisimid (1)
- Perylene Bisimide (1)
- Pflanzen (1)
- Pflanzenaussterben (1)
- Phagozytose (1)
- Pharmaceutical Analysis (1)
- Phase Transition (1)
- Phasenkontrastverfahren (1)
- Phasenmehrdeutigkeit (1)
- Phasenvariation (1)
- Phenotypic switch (1)
- Phonetik (1)
- Photocatalysis (1)
- Photoconductivity (1)
- Photoelektronenspektroskopie (1)
- Photolysis (1)
- Photosensibilisator (1)
- Phthalocyanin (1)
- Phänologie (1)
- Pilzkörper (1)
- PinT (1)
- Planare Graphen (1)
- Plant cuticle (1)
- Plant fertilization (1)
- Plasmaantrieb (1)
- Plasmamembran (1)
- Plastizität (1)
- Pluronic (1)
- Pneumoviruses (1)
- Point-of-Care-testing (1)
- Polkörper (1)
- Pollen (1)
- Poly(glycidol)s (1)
- Polycyclic Aromatic Hydrocarbons (1)
- Polyeder (1)
- Polymerlösung (1)
- Polymorphismus (1)
- Polyneuropathie (1)
- Polyoxazoline (1)
- Polyoxazolines (1)
- Polyphenylenvinylenanaloga (1)
- Polyzyklen (1)
- Pontryagin maximum principle (1)
- Post-Quantum-Kryptografie (1)
- Precipitation (1)
- Prescriptive Analytics (1)
- Princes' War in South Germany (1)
- Problemlösefähigkeiten (1)
- Procurement (1)
- Progenitor (1)
- Prognose (1)
- Propositional proof system (1)
- Protease-sensitive release (1)
- Proteasen (1)
- Protein Purification (1)
- Protein purification (1)
- Proteinkinase D (1)
- Proteinmodifizierung (1)
- Protonenreduktion (1)
- Präzisionsmedizin (1)
- Public Debt Meanagement (1)
- Public Spending (1)
- QM/MM (1)
- Quadruplex-DNS (1)
- Quality of Experience (1)
- Qualitätsindikator (1)
- Quanten-Hall-Effekt (1)
- Quanten-Monte-Carlo-Methode (1)
- Quantenmechanik (1)
- Quantenphasenübergänge (1)
- Quantum Anomalous Hall Effect (1)
- Quantum Field Theory (1)
- Quantum Monte Carlo method (1)
- Quantum phase transitions (1)
- REMPI (1)
- RNA (1)
- RNA granules (1)
- RNS (1)
- RSV (1)
- Radicals (1)
- Rastertunnelmikroskopie (1)
- Reaction mechanism (1)
- Reactive Hydrocarbon Species (1)
- Reaktionsmechanismus (1)
- Reaktivität (1)
- Receptor dynamics (1)
- Reduction (1)
- Refugees (1)
- Regenerative Medicine (1)
- Regression (1)
- Regularisation Methods (1)
- Regularisierung (1)
- Regularisierungsverfahren (1)
- Regulation (1)
- Regulatorischer T-Lymphozyt (1)
- Relaxation method (1)
- Remote Sensing (1)
- Remote sensing (1)
- Resilienz (1)
- Resistance (1)
- Resistenz (1)
- Resveratrol (1)
- Rezeptorblocker (1)
- Rezidiv (1)
- Ribonuclease H2 (1)
- Riboregulation (1)
- Ringöffnungspolymerisation (1)
- Rnsstoffwechsel (1)
- Roboterwettbewerbe (1)
- Robotik (1)
- Rossameise (1)
- Ruthenium complexes (1)
- Ruthenium-Photosensibilisator (1)
- Röntgenkristallographie (1)
- Röntgenmikroskopie (1)
- Röntgenstreuung (1)
- SANS (1)
- SAR (1)
- SAXS (1)
- SIM (1)
- SIPGP (1)
- SLC2A3 (1)
- SMN (1)
- Salmonella (1)
- Salmonella Typhimurium (1)
- Samenpflanzen (1)
- Satellit (1)
- Scaffold (1)
- Scaffold <Tissue Engineering> (1)
- Scaffold bone implant (1)
- Schimpanse (1)
- Schizophrenie (1)
- Schizosaccharomyces pombe (1)
- Schlaganfall (1)
- Schließzellfunktion (1)
- Schnelltest (1)
- Schur ring (1)
- Secretion (1)
- Selective extraction (1)
- Self-Assembly (1)
- Self-Assembly in Water (1)
- Sensoren (1)
- Sensorfusion (1)
- Sensors (1)
- Sequential Quadratic Hamiltonian scheme (1)
- Sequenzwiederholung (1)
- Serious game (1)
- Serotonin (1)
- Shape Optimization (1)
- Signaltransduktion (1)
- Siliciumcarbid (1)
- Silicon-Boron Exchange (1)
- Silicon-Boron exchange (1)
- Silizium-Bor-Austausch (1)
- Site-specific protein conjugation (1)
- Skalierbarkeit (1)
- Slave-Boson-Verfahren (1)
- Small RNA (1)
- Small angle X-ray scattering (1)
- Social action effects (1)
- Sociomotor gaze control (1)
- Soft matter (1)
- Software-defined networking (1)
- Solid state physic (1)
- Solubilisation (1)
- Source Code Generation (1)
- Soziale Handlungseffekte (1)
- Soziomotorische Blickkontrolle (1)
- Space Debris (1)
- Spatial resolution (1)
- Speckle tracking (1)
- Spectral Asymmetry (1)
- Sphingosinanaloga (1)
- Sphingosinkinase (1)
- Spider Silk (1)
- Spielmechanik (1)
- Spin Defekt (1)
- Spin defect (1)
- Spin labels (1)
- Spin-Orbit-Torque (1)
- Spin-Sonde (1)
- Spinnenseide (1)
- Spintronics (1)
- Spracherwerb (1)
- Squaraine (1)
- Stammvielfalt (1)
- Standortplanung (1)
- Staphylococcus aureus (1)
- Stark korrelierte Elektronen (1)
- Statische Analyse (1)
- SteC (1)
- Sterblichkeit (1)
- SthK-bPAC (1)
- Stiff-Person Syndrom (1)
- Stiff-person syndrome (1)
- Striatum (1)
- Strongly correlated electrons (1)
- Structural elucidation (1)
- Strukturaufklärung (1)
- Strukturbiologie (1)
- Störstelle (1)
- Substantia nigra (1)
- Sulfoximin (1)
- Super-resolution microscopy (1)
- Superconductivity (1)
- Superresolution microscopy (1)
- Supply Chain (1)
- Supply Chain Management (1)
- Supraleitung (1)
- Supramolecular Chemistry (1)
- Surface modifiaction (1)
- Survival Motor Neuron (1)
- Synapse (1)
- Synaptic plasticity (1)
- Synaptonemaler Komplex (1)
- Synchronisation (1)
- Synchronitätsmessung (1)
- Synchrotron Radiation (1)
- Synchrotronstrahlung (1)
- Systembiologie (1)
- T cell engaging Antibody (1)
- TCS (1)
- TDRD3 (1)
- TERB1-TERB2-MAJIN (1)
- TFIIH (1)
- TH2 Immunantwort (1)
- TLR signaling (1)
- TOP3b (1)
- TTF complex (1)
- Tandem-Massenspektrometrie (1)
- Targeted drug delivery (1)
- Technische Optik (1)
- Teleconnection (1)
- Telekonnektion (1)
- Telemetrie (1)
- Telomerase (1)
- Temporal Resolution (1)
- Terminal domains (1)
- Terminale Domaine (1)
- Textverstehen (1)
- Theoretical Chemistry (1)
- Therapeutisches System (1)
- Thermodynamics (1)
- Thermospheric density uncertainty (1)
- Thermosphärische Dichteunsicherheit (1)
- Thrombopoiesis (1)
- Time Series (1)
- Tissue engineering (1)
- Toll-like-Rezeptoren (1)
- Tongue (1)
- Topological Materials (1)
- Topologische Phase (1)
- Topologischer Isolator (1)
- Total Synthesis (1)
- Totale Variation (1)
- Totalsynthese (1)
- TraDIS (1)
- Transient absorption (1)
- Transiente Absorption (1)
- Transitionmetal (1)
- Transkranielle Sonographie (1)
- Transkription (1)
- Transkriptionsfaktor (1)
- Transkriptomanalyse (1)
- Transkriptomik anlyze (1)
- Translation <Genetik> (1)
- Transpiration <Pflanzen> (1)
- Treg (1)
- Trend (1)
- Trophic Factors (1)
- Trypanosoma Brucei (1)
- Trypanosomen (1)
- Trypanosomes (1)
- Tsetsefliege (1)
- Two-photon absorption (1)
- UBE2S (1)
- Ubiquitin-PA (1)
- Ubiquitin-Protein-Ligase (1)
- Ubiquitin-conjugating enzyme (1)
- Ubiquitinierung (1)
- Ultra-Wideband (UWB) radio ranging (1)
- Ultraschall (1)
- Umbrella Sampling (1)
- Uncertainty realism (1)
- Unconventional Monetary Policy (1)
- Unkonventionelle Geldpolitik (1)
- Unmanned Aerial Vehicle (UAV) (1)
- Unsicherheitsrealismus (1)
- Unstrukturiertes Gitter (1)
- Verhalten (1)
- Verhaltenskontrolle (1)
- Verunreinigung (1)
- Very-long-chain aliphatic (1)
- Vesikelbildung (1)
- Vessel wall (1)
- Videoübertragung (1)
- Virtualisierung (1)
- Viskosität (1)
- Visuelle Aufmerksamkeit (1)
- Vorläufer (1)
- Wald (1)
- Waldstruktur (1)
- War in south Germany (1)
- Warteschlangentheorie (1)
- Wasseroxidation (1)
- Wasserstofferzeugung (1)
- Water (1)
- Water stress (1)
- Weiche Materie (1)
- Wespen (1)
- Winkelaufgelöste Photoemissionspektroskopie (1)
- Wirkstoff-Träger-System (1)
- Wirt-Gast-Beziehung (1)
- Wissensencodierung (1)
- X-ray crystallography (1)
- X-ray diffraction (1)
- Yeast (1)
- Zellzyklus (1)
- Zentriolen (1)
- Zero-divisor graph (1)
- Zink-Finger-Proteine (1)
- Zunge (1)
- Zweiphotonenabsorption (1)
- Zweite Fremdsprache (1)
- Zyklisierung (1)
- [FeFe] hydrogenase mimic (1)
- [FeFe]-Hydrogenase Imitator (1)
- aGPCR (1)
- adaptive traits (1)
- adhesion-GPCR (1)
- adrenal gland (1)
- adrenergic receptor (1)
- adrenocortical carcinoma (1)
- allogeneic stem cell transplantation (1)
- amyotrophe Lateralsklerose (1)
- antimicrobial (1)
- articular cartilage progenitor cells (1)
- articular chondrocytes (1)
- atopic diseases (1)
- attack-aware (1)
- autoantibody (1)
- autophagocytose (1)
- autophagy (1)
- bacterial lipid rafts (1)
- bees (1)
- behavior (1)
- beta diversity (1)
- bicuculline (1)
- bilingualism (1)
- binding mode (1)
- biochemistry (1)
- biodistribution (1)
- biodiversity (1)
- biodiversity response (1)
- biofabrication (1)
- bioimage analysis (1)
- biokinetics (1)
- biopsy (1)
- bioreactor (1)
- biradical (1)
- blood nerve barrier (1)
- bone marrow (1)
- boron (1)
- borylation (1)
- bumblebee*s (1)
- cAMP (1)
- cancer-related fatigue (1)
- candida (1)
- candida albicans (1)
- capillary electrophoresis (1)
- cardiac hypertrophy (1)
- cartilage (1)
- catalysis (1)
- cell-based therapy (1)
- channelrhodopsin (1)
- chlamydia (1)
- chondrogene Differenzierung (1)
- chromosomes telomere-led movement (1)
- circadian rhythms (1)
- claudin-12 (1)
- co-culture (1)
- cochlea implant (1)
- coherent imaging (1)
- compartments (1)
- computed tomography (1)
- conflict (1)
- conjugated electrochromic polymers (1)
- connectomics (1)
- cooperative (1)
- corneal confocal microscopy (1)
- correlation (1)
- cross-coupling (1)
- cushing's syndrome (1)
- cytokine release syndrome (1)
- cytoskeleton (1)
- dCIRL (1)
- dSTORM (1)
- denial of service (1)
- developmental differentiation (1)
- diabetic cardiomyopathy (1)
- diagnostics (1)
- diastolic dysfunction (1)
- diet (1)
- diimidoborane (1)
- disease model (1)
- distance (1)
- distribution (1)
- double-strand break repair (1)
- drug delivery (1)
- drug repurposing (1)
- dual RNA-seq (1)
- dyad (1)
- dynamic (1)
- e-mail (1)
- echocardiography (1)
- ecology (1)
- ecosystem services (1)
- effector protein (1)
- electrochromic device (1)
- electron microscopy (1)
- elliptic curves (1)
- emotions (1)
- entomology (1)
- eosinophil (1)
- exciton coupling (1)
- expression (1)
- extinction dynamics (1)
- fabry disease (1)
- fatigue (1)
- fibromyalgia sydrome (1)
- finite volume methods (1)
- focused ion-beam scanning electron microscopy (1)
- foraging activity (1)
- foxtapeworm (1)
- fullerene (1)
- functional membrane microdomains (1)
- functional studies (1)
- fungus (1)
- germinative cell (1)
- gezielte Therapie (1)
- glycine receptor autoantibodies (1)
- glycophytes (1)
- grating interferometry (1)
- guard cells (1)
- hematopoiesis (1)
- hexadehydro-Diels-Alder (1)
- hippocampus (1)
- homoFRET (1)
- honeybee (1)
- honeybee*s (1)
- honor (1)
- honour (1)
- iLID (1)
- iPSC (1)
- image quality (1)
- impurities (1)
- in-line phase contrast (1)
- in-silico model (1)
- inflammation (1)
- insects (1)
- interleukin-5 signaling (1)
- internal dosimetry (1)
- interphase gap (1)
- interpulse interval (1)
- intracellular (1)
- intrusion detection (1)
- iridium photosensitizer (1)
- isogeny-based cryptography (1)
- isotopically labelled peptides (1)
- kinase (1)
- labeling techniques (1)
- lamellar micelles (1)
- land use (1)
- language attrition (1)
- learning (1)
- lipid rafts (1)
- liquid chromatography (1)
- liquid-metal-jet (1)
- liquids (1)
- local adaptation (1)
- low resolution data (1)
- magnetization (1)
- matrix metalloproteinase (1)
- mechanistische Modellierung (1)
- mechanochemical degradation (1)
- meiosis (1)
- melanoma dedifferentiation (1)
- melt electrowriting (1)
- membrane dynamics (1)
- metabolic adaptation (1)
- metabolic theory of ecology (1)
- metagenomics (1)
- metallosupramolecular chemistry (1)
- microbial ecology and evolution (1)
- microelectrode array (1)
- microswimming (1)
- mikrobielle Ökologie und Evolution (1)
- moderate resolution data (1)
- molecular engineering (1)
- motility (1)
- mram (1)
- myelin barrier (1)
- narrative text (1)
- nature conservation (1)
- network function virtualization (1)
- neuroethology (1)
- neuromodulation (1)
- neuronal visual system (1)
- neuropeptides (1)
- neutron reflectometry (1)
- neutrophil (1)
- nociception (1)
- nutrients (1)
- nutrition (1)
- oligomers (1)
- optogenetic (1)
- osteoarthritis (1)
- pain (1)
- pangenome (1)
- paraffins (1)
- pathophysiological mechanisms (1)
- pattern (1)
- peptide (1)
- peptide engineering (1)
- peptide-based interleukin-5 inhibitor (1)
- perception (1)
- perceptual simulation (1)
- perceptual support (1)
- performance modeling (1)
- phagosome maturation (1)
- phonetics (1)
- phonology (1)
- phosphorylation (1)
- photodynamic therapy (1)
- phylogenetic inertia (1)
- phylogenetische Trägheit (1)
- platelets (1)
- polarized epithelium (1)
- pollen (1)
- poly(2-oxazine)s (1)
- poly(2-oxazoline)s (1)
- polycycles (1)
- polyethism (1)
- polyneuropathy (1)
- polyradiculoneuropathy (1)
- post-disturbance logging (1)
- precision medicine (1)
- preclinical PET (1)
- primate (1)
- problem solving skills (1)
- proboscis extension response (1)
- protease (1)
- protein kinase a (1)
- protein regulation and expression (1)
- proton reduction (1)
- psychosocial resilience (1)
- qNMR (1)
- rapid evolution (1)
- reception (1)
- receptor (1)
- regulation of gene expression (1)
- replication (1)
- reputation (1)
- resilience (1)
- resveratrol (1)
- ring-opening polymerization (1)
- ruthenium photosensitizer (1)
- salinen Wachstumsbedingungen (1)
- salt stress (1)
- schnelle Evolution (1)
- secondary site infection (1)
- self-activation (1)
- self-aware (1)
- signal to noise ratio (1)
- signalling (1)
- silicon-boron exchange (1)
- similarity (1)
- situation model (1)
- skin (1)
- skin biopsy (1)
- small RNA (1)
- small fiber pathology (1)
- small proteins (1)
- software-definded networking (1)
- somatic resilience (1)
- somatostatin receptor antagonists (1)
- species richness (1)
- spectroscopy (1)
- sphingosine (1)
- spin-orbit-torque (1)
- ssVEP (1)
- stiff person syndrome (1)
- strain diversity (1)
- strain rate (1)
- structural mechanism (1)
- structure analysis (1)
- super-resolution array tomography (1)
- super-resolution microscopy (1)
- synaptic plasticity (1)
- synaptische Plastizität (1)
- tandem mass spectrometry (1)
- targeted therapy (1)
- temporal development (1)
- temporal information transfer (1)
- text comprehension (1)
- the Elector Friedrich (1)
- therapy (1)
- time-resolved anisotropy (1)
- tissue regeneration (1)
- tool (1)
- tool-use (1)
- topological insulator (1)
- total variation (1)
- tracheal cytotoxin (1)
- trachomatis (1)
- transcranial sonography (1)
- transcription/replication conflicts (1)
- transcriptional regulation (1)
- transcriptome data analysis (1)
- transcriptomic analysis (1)
- transglutaminase (1)
- transient dynamics (1)
- trypanosome (1)
- tsetse fly (1)
- tumour (1)
- tyrosine kinase (1)
- vector-parasite interaction (1)
- vesicles (1)
- viability (1)
- video streaming (1)
- virulence (1)
- voltage clamp (1)
- wasps (1)
- water oxidation (1)
- water quality (1)
- well-balancing (1)
- worm-like micelles (1)
- x-ray imaging (1)
- x-ray inline phase contrast (1)
- x-ray microscopy (1)
- yeast (1)
- yoga (1)
- zeitlich Informationsübertragung (1)
- zonal Hydrogels (1)
- Öffentliche Ausgaben (1)
- Öffentliches Schuldenmanagement (1)
- Ökologie (1)
- Ökosystemdienstleistung (1)
- Übergangsmetallkomplex (1)
- Übergangsmetallkomplexe (1)
- Überlagerung <Mathematik> (1)
- α-aminoboronates (1)
Institute
- Graduate School of Life Sciences (96)
- Theodor-Boveri-Institut für Biowissenschaften (33)
- Institut für Organische Chemie (13)
- Physikalisches Institut (11)
- Institut für Anorganische Chemie (10)
- Institut für Informatik (10)
- Rudolf-Virchow-Zentrum (10)
- Institut für Mathematik (9)
- Institut für Pharmazie und Lebensmittelchemie (9)
- Julius-von-Sachs-Institut für Biowissenschaften (9)
Sonstige beteiligte Institutionen
- Airbus Defence and Space GmbH (1)
- Biomedical Center Munich, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München (1)
- Department of Veterinary Sciences, Experimental Parasitology, Ludwig-Maximilians-Universität München (1)
- Deutsches Zentrum für Luft- und Raumfahrt (1)
- European Molecular Biology Laboratory, Heidelberg, Germany (1)
- Fraunhofer-Institut für Silicatforschung ISC (1)
- Institut für Organische Chemie, RWTH Aachen (1)
- Lehrkrankenhaus II. Medizinische Klinik Klinikum Coburg (1)
- Max-Delbrück-Center für molekulare Medizin, Berlin (1)
- National Park "Bavarian Forest" (1)
Small proteins, often defined as shorter than 50 amino acids, have been implicated
in fundamental cellular processes. Despite this, they have been largely understudied throughout all domains of life, since their size often makes their identification and characterization challenging.
This work addressed the knowledge gap surrounding small proteins with a focus
on the model bacterial pathogen Salmonella Typhimurium. In a first step,
new small proteins were identified with a combination of computational and experimental approaches. Infection-relevant datasets were then investigated with
the updated Salmonella annotation to prioritize promising candidates involved in virulence.
To implement the annotation of new small proteins, predictions from the algorithm
sPepFinder were merged with those derived from Ribo-seq. These were added to the Salmonella annotation and used to (re)analyse different datasets. Information
regarding expression during infection (dual RNA-seq) and requirement for virulence (TraDIS) was collected for each given coding sequence. In parallel,
Grad-seq data were mined to identify small proteins engaged in intermolecular
interactions.
The combination of dual RNA-seq and TraDIS lead to the identification of small
proteins with features of virulence factors, namely high intracellular induction
and a virulence phenotype upon transposon insertion. As a proof of principle of
the power of this approach in highlighting high confidence candidates, two small
proteins were characterized in the context of Salmonella infection.
MgrB, a known regulator of the PhoPQ two-component system, was shown to be essential for the infection of epithelial cells and macrophages, possibly via its stabilizing effect on flagella or by interacting with other sensor kinases of twocomponent
systems. YjiS, so far uncharacterized in Salmonella, had an opposite role in infection, with its deletion rendering Salmonella hypervirulent. The mechanism underlying this, though still obscure, likely relies on the interaction with
inner-membrane proteins.
Overall, this work provides a global description of Salmonella small proteins in
the context of infection with a combinatorial approach that expedites the identification
of interesting candidates. Different high-throughput datasets available for
a broad range of organisms can be analysed in a similar manner with a focus on small proteins. This will lead to the identification of key factors in the regulation
of various processes, thus for example providing targets for the treatment of bacterial
infections or, in the case of commensal bacteria, for the modulation of the microbiota composition.
In several countries, a decline in mortality, case-fatality and recurrence rates of stroke was observed. However, studies investigating sex-specific and subtype-specific (pathological and etiological) time trends in stroke mortality, case-fatality and recurrence rates are scarce, especially in Germany. The decline in ischemic stroke mortality and case-fatality might be associated with the high quality of acute care of ischemic stroke, but the exact determinants of early outcome remains unknown for Germany.
Therefore, as first step of this thesis, we investigated the time trends of subtype- and sex-specific age- standardized stroke mortality rates in Germany from 1998 to 2015, by applying joinpoint regression on official causes of death statistics, provided by the Federal Statistical Office. Furthermore, a regional comparison of the time trends in stroke mortality between East and West was conducted. In the second step, time trends in case-fatality and stroke recurrence rates were analyzed using data from a population- based stroke register in Germany between 1996 and 2015. The analysis was stratified by sex and etiological subtype of ischemic stroke. In the third step, quality of stroke care and the association between adherence to measures of quality of acute ischemic stroke care and in-hospital mortality was estimated based on data from nine regional hospital-based stroke registers in Germany from the years 2015 and 2016.
We showed that in Germany, age-standardized stroke mortality declined by over 50% from 1998 to 2015 both, in women and men. Stratified by the pathological subtypes of stroke, the decrease in mortality was larger in ischemic stroke compared to hemorrhagic stroke. Different patterns in the time trends of stroke were observed for stroke subtypes, regions in Germany (former Eastern part of Germany (EG), former Western part of Germany (WG)) and sex, but in all strata a decline was found. By applying joinpoint regression, the number of changes in time trend differed between the regions and up to three changes in the trend in ischemic stroke mortality were detected. Trends in hemorrhagic stroke were in parallel between the regions with up to one change (in women) in joinpoint regression. Comparing the regions, stroke mortality was higher in EG compared to WG throughout the whole observed time period, however the differences between the regions started to diminish from 2007 onwards.
Further it was found that, based on the population-based Erlangen Stroke Project (ESPro), case-fatality and recurrence rates in ischemic stroke patients are still high in Germany. 46% died and 20% got a recurrent stroke within the first five years after stroke. Case-fatality rates declined statistically significant from 1996 to 2015 across all ischemic stroke patients and all etiological subtypes of ischemic stroke. Based on Cox regression no statistically significant decrease in stroke recurrence was observed.
Based on the pooled data of nine regional hospital-based stroke registers from the years 2015 and 2016 covering about 80% of all hospitalized stroke patients in Germany, a high quality of care of acute ischemic stroke patients, measured via 11 evidence-based quality indicators (QI) of process of care, was observed. Across all registers, most QI reached the predefined target values for good quality of stroke care. 9 out of 11 QI showed a significant association with 7-day in-hospital mortality. An inverse linear association between overall adherence to QI and 7-day in-hospital mortality was observed.
In conclusion, stroke mortality and case-fatality showed a favorable development over time in Germany, which might partly be due to improvements in acute treatment. This is supported by the association between overall adherence to quality of care and in-hospital mortality. However, there might be room for improvements in long-term secondary prevention, as no clear reduction in recurrence rates was observed.
This thesis aims at providing efficient and side-channel protected implementations of isogeny-based primitives, and at their application in threshold protocols. It is based on a sequence of academic papers.
Chapter 3 reviews the original variable-time implementation of CSIDH and introduces several optimizations, e.g. a significant improvement of isogeny computations by using both Montgomery and Edwards curves. In total, our improvements yield a speedup of 25% compared to the original implementation.
Chapter 4 presents the first practical constant-time implementation of CSIDH. We describe how variable-time implementations of CSIDH leak information on private keys, and describe ways to mitigate this. Further, we present several techniques to speed up the implementation. In total, our constant-time implementation achieves a rather small slowdown by a factor of 3.03.
Chapter 5 reviews practical fault injection attacks on CSIDH and presents countermeasures. We evaluate different attack models theoretically and practically, using low-budget equipment. Moreover, we present countermeasures that mitigate the proposed fault injection attacks, only leading to a small performance overhead of 7%.
Chapter 6 initiates the study of threshold schemes based on the Hard Homogeneous Spaces (HHS) framework of Couveignes. Using the HHS equivalent of Shamir’s secret sharing in the exponents, we adapt isogeny based schemes to the threshold setting. In particular, we present threshold versions of the CSIDH public key encryption and the CSI-FiSh signature scheme.
Chapter 7 gives a sieving algorithm for finding pairs of consecutive smooth numbers that utilizes solutions to the Prouhet-Tarry-Escott (PTE) problem. Recent compact isogeny-based protocols, namely B-SIDH and SQISign, both require large primes that lie between two smooth integers. Finding such a prime can be seen as a special case of finding twin smooth integers under the additional stipulation that their sum is a prime.
Identification of a novel LysR-type transcriptional regulator in \(Staphylococcus\) \(aureus\)
(2021)
Staphylococcus aureus is a facultative pathogen which causes a variety of infections. The treatment of staphylococcal infections is complicated because the bacteria is resistant to multiple common antibiotics. S. aureus is also known to express a variety of virulence factors which modulate the host’s immune response in order to colonize and invade certain host cells, leading to the host cell’s death. Among the virulence factors is a LysR-type transcriptional regulator (lttr) which is required for efficient colonization of secondary organs. In a recent report, which used transposon screening on S. aureus-infected mice, it was found that the amount of a novel lttr852 mutant bacteria recovered from the kidneys was significantly lower compared to the wildtype strains.
This doctoral thesis therefore focused on phenotypical and molecular characterization of lttr852. An assessment of the S. aureus biofilm formation and the hemolysis revealed that lttr852 was not involved in the regulation of these virulence processes. RNA-sequencing for potential target genes of lttr852 identified differentially expressed genes that are involved in branched chain amino-acid biosynthesis, methionine sulfoxide reductase and copper transport, as well as a reduced transcription of genes encoding urease and of components of pyrimidine nucleotides. Promoter fusion with GFP reporters as as well as OmniLog were used to identify conditions under which the lttr852 was active. The promoter studies showed that glucose and high temperatures diminish the lttr852 promoter activity in a time-dependent manner, while micro-aerobic conditions enhanced the promoter activity. Copper was found to be a limiting factor. In addition, the impact on promoter activity of the lttr852 was tested in the presence of various regulators, but no central link to the genes involved in virulence was identified.
The present work, thus, showed that lttr852, a new member of the class of LysR-type transcriptional regulators in S. aureus, has an important role in the rapid adaptation of S. aureus to the changing microenvironment of the host.
Because of its complexity and intricacy, studying the nervous system is often challenging. Fortunately, the small nematode roundworm Caenorhabditis elegans is well established as a model system for basic neurobiological research. The C. elegans model is also the only organism with a supposedly complete connectome, an organism-wide map of synaptic connectivity resolved by electron microscopy, which provides some understanding of how the nervous system works as a whole. However, the number of available data-sets is small and the connectome contains errors and gaps. One example of this concerns electrical synapses. Electrical synapses are formed by gap junctions and difficult to map due to their often ambiguous morphology in electron micrographs, leading to misclassification or omission. On the other hand, chemical synapses are more easily mapped, but many aspects of their mode of operation remain elusive and their role in the C. elegans connectome is oversimplified. A comprehensive understanding of signal transduction of neurons between each other and other cells will be indispensable for a comprehensive understanding of the nervous system. In this thesis, I approach these challenges with a combination of advanced light and electron microscopy techniques.
First, this thesis describes a strategy to increase synaptic specificity in connectomics. Specifically, I classify gap junctions with a high degree of confidence. To achieve this, I utilized array tomography (AT). In this thesis, AT is adapted for high-pressure freezing to optimize for structure preservation and for super-resolution light microscopy; in this manner, I aim to bridge the gap between light and electron microscopy resolutions. I call this adaptation super-resolution array tomography (srAT). The srAT approach made it possible to clearly identify and map gap junctions with high precision and accuracy. The results from this study showcased the feasibility of incorporating electrical synapses into connectomes in a systematic manner, and subsequent studies have used srAT for other models and questions.
As mentioned above, the C. elegans connectomic model suffers from a shortage of datasets. For most larval stages, including the special dauer larval stage, connectome data is completely missing up to now. To obtain the first partial connectome data-set of the C. elegans dauer larva, we used focused ion-beam scanning electron microscopy (FIB-SEM). This technique offers an excellent axial resolution and is useful for acquiring large volumes for connectomics. Together with our collaborators, I acquired several data-sets which enable the analysis of dauer stage-specific “re-wiring” of the nervous system and thus offer valuable insights into connectome plasticity/variability.
While chemical synapses are easy to map relative to electrical synapses, signal transduction via chemical transmitters requires a large number of different proteins and molecular processes acting in conjunction in a highly constricted space. Because of the small spatial scale of the synapse, investigating protein function requires very high resolution, which electron tomography provides. I analyzed electron tomograms of a worm-line with a mutant synaptic protein, the serine/threonine kinase SAD-1, and found remarkable alterations in several architectural features. My results confirm and re-contextualize previous findings and provide new insight into the functions of this protein at the chemical synapse.
Finally, I investigated the effectiveness of our methods on “malfunctioning,” synapses, using an amyotrophic lateral sclerosis (ALS) model. In the putative synaptopathy ALS, the mechanisms of motor neuron death are mostly unknown. However, mutations in the gene FUS (Fused in Sarcoma) are one known cause of the disease. The expression of the mutated human FUS in C. elegans was recently shown to produce an ALS-like phenotype in the worms, rendering C. elegans an attractive disease model for ALS. Together with our collaboration partners, I applied both srAT and electron tomography methods to “ALS worms” and found effects on vesicle docking. These findings help to explain electrophysiological recordings that revealed a decrease in frequency of mini excitatory synaptic currents, but not amplitudes, in ALS worms compared to controls. In addition, synaptic endosomes appeared larger and contained electron-dense filaments in our tomograms. These results substantiate the idea that mutated FUS impairs vesicle docking and also offer new insights into further molecular mechanisms of disease development in FUS-dependent ALS. Furthermore, we demonstrated the broader applicability of our methods by successfully using them on cultured mouse motor neurons.
Overall, using the C. elegans model and a combination of light and electron microscopy methods, this thesis helps to elucidate the structure and function of neuronal synapses, towards the aim of obtaining a comprehensive model of the nervous system.
The present thesis demonstrates how different thermodynamic aspects of self-assembly and stimuli-responsive properties in water can be encoded on the structure of π-amphiphiles, consisting of perylene or naphthalene bisimide cores. Initially, quantitative thermodynamic insights into the entropically-driven self-assembly was studied for a series of naphthalene bisimides with UV/Vis and ITC measurements, which demonstrated that their thermodynamic profile of aggregation is heavily influenced by the OEG side chains. Subsequently, a control over the bifurcated thermal response of entropically driven and commonly observed enthalpically driven self-assembly was achieved by the modulation of glycol chain orientation. Finally, Lower Critical Solution Temperature (LCST) phenomenon observed for these dyes was investigated as a precise control of this behavior is quintessential for self-assembly studies as well as to generate ‘smart’ materials. It could be shown that the onset of phase separation for these molecules can be encoded in their imide substituents, and they are primarily determined by the supramolecular packing, rather than the hydrophobicity of individual monomers.
The technique to manipulate cells or living animals by illumination after gene transfer of light-sensitive proteins is called optogenetics. Successful optogenetics started with the use of the light-gated cation channel channelrhodopsin-2 (ChR2). After early demonstrations of the power of ChR2, further light-sensitive ion channels and ion pumps were recruited to the optogenetic toolbox. Furthermore, mutations and chimera of ChR2 improved its versatility.
However, there is still a need for improved optogenetic tools, e.g. with higher permeability for calcium or better expression in the plasma membrane. In this thesis, my work focuses on the design of highly functional channelrhodopsins with enhanced Na+ and Ca2+ conductance.
First, I tested different N-terminal signal peptides to improve the plasma membrane targeting of Channelrhodopsins. We found that a N-terminal peptide, named LR, could improve the plasma membrane targeting of many rhodopsins. Modification with LR contributed to three to ten-fold larger photocurrents (than that of the original version) of multiple channelrhodopsins, like ChR2 from C. reinhardtii (CrChR2), PsChR, Chrimson, CheRiff, CeChR, ACRs, and the light-activated pump rhodopsins KR2, Jaw, HR.
Second, by introducing point mutation, I could further improve the light sensitivity and photocurrent of different channelrhodopsins. For instance, ChR2-XXM 2.0, ChR2-XXL 2.0 and PsChR D139H 2.0 exhibited hundred times larger photocurrents than wild type ChR2 and they show high light sensitivity. Also, the Ca2+ permeable channelrhodopsins PsCatCh 2.0f and PsCatCh 2.0e show very large photocurrents and fast kinetics. In addition, I also characterized a novel bi-stable CeChR (from the acidophilic green alga Chlamydomonas eustigma) with a much longer closing time.
Third, I analysed the ion selectivity of different ChRs, which provides a basis for rational selection of channelrhodopsins for different experimental purposes. I demonstrate that ChR2, Chronos, Chrimson, CheRiff and CeChR are highly proton conductive, compared with wild type PsChR. Interestingly, Chronos has the lowest potassium conductance among these channelrhodopsins. Furthermore, I found that mutation of an aspartate in TM4 of ChR2 (D156) and PsChR (D139) to histidine obviously increased both the sodium and calcium permeability while proton conductance was reduced. PsChR D139H 2.0 has the largest sodium conductance of any published channelrhodopsin variants. Additionally, I generated PsCatCh 2.0e which exhibits a ten-fold larger calcium current than the previously reported Ca2+ transporting CrChR2 mutant CatCh.
In summary, my research work
1.) described strategies for improving plasma membrane trafficking efficiency of opsins;
2.) yielded channelrhodopsins with fast kinetics or high light sensitivity;
3.) provided optogenetic tools with improved calcium and sodium conductance.
We could also improve the performance of channelrhodopsins with distinct action spectra, which will facilitate two-color neural excitation, both in-vitro and in-vivo.
This thesis aims to investigate the form-phase diagram of aqueous solutions of the triblock copolymer Pluronic P123 focusing on its high-temperature phases. P123 is based on polyethylene as well as polypropylene oxide blocks and shows a variety of di erent temperaturedependent micelle morphologies or even lyotropic liquid crystal phases in aqueous solutions. Besides the already well-studied spherical aggregates at intermediate temperatures, the size and internal structure of both worm-like and lamellar micelles, which appear near the cloud point, is determined using light, neutron and X-ray scattering. By combining the results of time-resolved dynamic light as well as small-angle neutron and X-ray scattering experiments, the underlying structural changes and kinetics of the sphere-to-worm transition were studied supporting the random fusion process, which is proposed in literature. For temperatures near the cloud point, it was observed that aqueous P123 solutions below the critical crystallization concentration gelate after several hours, which is linked to the presence and structure of polymeric surface layers on the sample container walls as shown by neutron re ectometry
measurements. Using a hierarchical model for the lamellar micelles including their periodicity as well as domain and overall size, it is possible to unify the existing results in literature and propose a direct connection between the near-surface and bulk properties of P123 solutions at temperatures near the cloud point.
Neuropathies are a group of potentially treatable diseases with an often disabling and restricting course. Amyotrophic lateral sclerosis (ALS) is a lethal disease without causal treatment possibilities. The objective of this study was to examine the diagnostic utility of HRUS for the differentiation of subtypes of axonal and demyelinating neuropathies and to investigate its utility for the sonological differentiation of ALS.
The hypothetical statement that neuropathy causes enlargement of peripheral nerves compared to healthy controls proved to be right, but the adjunctive assumption that ALS does not cause enlargement of peripheral nerves proved to be wrong – in patients with ALS slight enlargement of peripheral nerves was visible as well. The statement that nerve enlargement can be detected by measurement of the cross-sectional area (CSA) and the longitudinal diameter (LD) with comparable results proved to be right, but the enlargement was slightly less present by measurement of the LD. The statement that axonal and demyelinating neuropathies show distinct patterns of nerve enlargement must be answered differentiated: The comparison between axonal and demyelinating neuropathies showed a stronger nerve enlargement in patients with demyelinating neuropathies than in patients with axonal neuropathies at proximal nerve segments of upper extremities. In the comparison of diagnose-defined subgroups of inflammatory demyelinating neuropathies a respective specific pattern of nerve enlargement was visible. However, remarkable in this context was the strong nerve enlargement found in patients with NSVN, which is classified as an axonal neuropathy. Stratification for specific findings in nerve biopsy did not lead to constructive differences in comparison between the different groups.
To sum up, HRUS showed to provide a useful contribution in the diagnostic process of neuropathies and ALS but needs to be integrated in a multimodal diagnostic approach.
Organoboron compounds are important building blocks in organic synthesis, materials science, and drug discovery. The development of practical and convenient ways to synthesize boronate esters attracted significant interest. Photoinduced borylations originated with stoichiometric reactions of arenes and alkanes with well-defined metal-boryl complexes. Now photoredox-initiated borylations, catalyzed either by transition-metal or organic photocatalysts, and photochemical borylations with high efficiency have become a burgeoning area of research. In this chapter, we summarize research in the field of photocatalytic C-X borylation, especially emphasizing recent developments and trends, based on transition-metal catalysis, metal-free organocatalysis and direct photochemical activation. We focus on reaction mechanisms involving single electron transfer (SET), triplet energy transfer (TET), and other radical processes.
We developed a highly selective photocatalytic C-F borylation method that employs a rhodium biphenyl complex as a triplet sensitizer and the nickel catalyst [Ni(IMes)2] (IMes = 1,3-dimesitylimidazolin-2-ylidene) for the C-F bond activation and defluoroborylation process. This tandem catalyst system operates with visible (400 nm) light and achieves borylation of a wide range of fluoroarenes with B2pin2 at room temperature in excellent yields and with high selectivity. Direct irradiation of the intermediary C-F bond oxidative addition product trans-[NiF(ArF)(IMes)2] leads to fast decomposition when B2pin2 is present. This destructive pathway can be bypassed by indirect excitation of the triplet states of the nickel(II) complex via the photoexcited rhodium biphenyl complex. Mechanistic studies suggest that the exceptionally long-lived triplet excited state of the Rh biphenyl complex used as the photosensitizer allows for efficient triplet energy transfer to trans-[NiF(ArF)(IMes)2], which leads to dissociation of one of the NHC ligands. This contrasts with the majority of current photocatalytic transformations, which employ transition metals as excited state single electron transfer agents. We have previously reported that C(arene)-F bond activation with [Ni(IMes)2] is facile at room temperature, but that the transmetalation step with B2pin2 is associated with a high energy barrier. Thus, this triplet energy transfer ultimately leads to a greatly enhanced rate constant for the transmetalation step and thus for the whole borylation process. While addition of a fluoride source such as CsF enhances the yield, it is not absolutely required. We attribute this yield-enhancing effect to (i) formation of an anionic adduct of B2pin2, i.e. FB2pin2-, as an efficient, much more nucleophilic {Bpin-} transfer reagent for the borylation/transmetalation process, and/or (ii) trapping of the Lewis acidic side product FBpin by formation of [F2Bpin]- to avoid the formation of a significant amount of NHC-FBpin and consequently of decomposition of {Ni(NHC)2} species in the reaction mixture.
We reported a highly selective and general photo-induced C-Cl borylation protocol that employs [Ni(IMes)2] (IMes = 1,3-dimesitylimidazoline-2-ylidene) for the radical borylation of chloroarenes. This photo-induced system operates with visible light (400 nm) and achieves borylation of a wide range of chloroarenes with B2pin2 at room temperature in excellent yields and with high selectivity, thereby demonstrating its broad utility and functional group tolerance. Mechanistic investigations suggest that the borylation reactions proceed via a radical process. EPR studies demonstrate that [Ni(IMes)2] undergoes very fast chlorine atom abstraction from aryl chlorides to give [NiI(IMes)2Cl] and aryl radicals. Control experiments indicate that light promotes the reaction of [NiI(IMes)2Cl] with aryl chlorides generating additional aryl radicals and [NiII(IMes)2Cl2]. The aryl radicals react with an anionic sp2-sp3 diborane [B2pin2(OMe)]- formed from B2pin2 and KOMe to yield the corresponding borylation product and the [Bpin(OMe)]•- radical anion, which reduces [NiII(IMes)2Cl2] under irradiation to regenerate [NiI(IMes)2Cl] and [Ni(IMes)2] for the next catalytic cycle.
A highly efficient and general protocol for traceless, directed C3-selective C-H borylation of indoles with [Ni(IMes)2] as the catalyst was achieved. Activation and borylation of N-H bonds by [Ni(IMes)2] is essential to install a Bpin moiety at the N-position as a traceless directing group, which enables the C3-selective borylation of C-H bonds. The N-Bpin group which is formed is easily converted in situ back to an N-H group by the oxidiative addition product of [Ni(IMes)2] and in situ-generated HBpin. The catalytic reactions are operationally simple, allowing borylation of of a variety of substituted indoles with B2pin2 in excellent yields and with high selectivity. The C-H borylation can be followed by Suzuki-Miyaura cross-coupling of the C-borylated indoles in an overall two-step, one-pot process providing an efficient method for synthesizing C3-functionalized heteroarenes.
This work consists of two parts. On the one hand, it describes simulation and
measurement of the effect of contaminations of the detector gas on the performance
of particle detectors, with special focus on Micromegas detectors. On the other
hand, it includes the setup of a production site for the finalization of drift panels
which are going to be used in the ATLAS NSW. The first part augments these
two parts to give an introduction into the theoretical foundations of gaseous particle
detectors.
The aim of this thesis was the preparation of a biomaterial ink for the fabrication of chemically crosslinked hydrogel scaffolds with low micron sized features using melt electrowriting (MEW). By developing a functional polymeric material based on 2-alkyl-2-oxazine (Ozi) and 2-alkyl-2-oxazoline (Ox) homo- and copolymers in combination with Diels-Alder (DA)-based dynamic covalent chemistry, it was possible to achieve this goal. This marks an important step for the additive manufacturing technique melt electrowriting (MEW), as soft and hydrophilic structures become available for the first time. The use of dynamic covalent chemistry is a very elegant and efficient method for consolidating covalent crosslinking with melt processing. It was shown that the high chemical versatility of the Ox and Ozi chemistry offers great potential to control the processing parameters. The established platform offers straight forward potential for modification with biological cues and fluorescent markers. This is essential for advanced biological applications. The physical properties of the material are readily controlled and the potential for 4D-printing was highlighted as well. The developed hydrogel architectures are excellent candidates for 3D cell culture applications. In particular, the low internal strength of some of the scaffolds in combination with the tendency of such constructs to collapse into thin strings could be interesting for the cultivation of muscle or nerve cells. In this context it was also possible to show that MEW printed hydrogel scaffolds can withstand the aspiration and ejection through a cannula. This allows the application as scaffolds for the minimally invasive delivery of implants or functional tissue equivalent structures to various locations in the human body.
This thesis describes the synthesis and reactivity of NHC-stabilized Lewis-acid/Lewis-base adducts of alanes and gallanes (NHC = Me2ImMe, iPr2Im, iPr2ImMe, Dipp2Im, Dipp2ImH). As this field of research has developed tremendously, especially in the last five years, the first chapter provides an overview of the current state of knowledge.
The influence of electronegative π-donor-substituents on the stability of the NHC alane adducts is examined in chapter 2. For this purpose, the carbene stabilized alanes (NHC)∙AlH3 (NHC = iPr2Im, Dipp2Im) were reacted with secondary amines of different steric demand and with phenols. The π-donor substituents saturate the Lewis acidic aluminium center and coordination of a second NHC-ligand was not observed. The strongly electronegative N and O substituents increase the Lewis acidity of the aluminium atom, which leads to stronger Al-CNHC as well as Al-H bonds, which inhibits the insertion of the carbene into the Al-H bond.
In Chapter 3 the development of the synthesis and reactivity of carbene-stabilized gallanes is presented. The synthesis of NHC gallane adducts (NHC)∙GaH3, (NHC)∙GaH2Cl and (NHC)∙GaHCl2 and their reactivity towards NHCs and cAACMe were investigated in detail. The reaction of the mono- and dichlorogallanes (NHC)∙GaH2Cl and (NHC)∙GaHCl2 (NHC = iPr2ImMe, Dipp2Im) with cAACMe led to insertion of the cAACMe with formation of chiral and achiral compounds depending on the sterically demand of the used NHC. Furthermore, the formation of bis-alkylgallanes was observed for the insertion of two equivalents of cAACMe with release of the NHC ligand.
Chapter 4 describes investigations concerning the synthesis and reactivity of NHC-stabilized iodoalanes and iodogallanes, which are suitable for the formation of cationic aluminium and gallium dihydrides. The reaction of (NHC)∙EH2I (E = Al, Ga) stabilized by the sterically less demanding NHCs (NHC = Me2ImMe, iPr2Im, iPr2ImMe) with an additional equivalent of the NHC led to the formation of the cationic bis-NHC aluminium and gallium dihydrides [(NHC)2∙AlH2]+I- and [(NHC)2∙GaH2]+I-. Furthermore, the influence of the steric demand of the used NHC was investigated. The adduct (Dipp2Im)∙GaH2I was reacted with an additional equivalent of Dipp2Im. Due to the bulk of the NHC used, rearrangement of one of the NHC ligands from normal to abnormal coordination occurred and the cationic gallium dihydride [(Dipp2Im)∙GaH2(aDipp2Im)] was isolated.
Chapter 5 of this thesis reports investigations concerning the reduction of cyclopentadienyl-substituted alanes and gallanes with singlet carbenes. NHC stabilized pentamethylcyclopentadienyl aluminium and gallium dihydrides (NHC)∙Cp*MH2 (E = Al, Ga) were prepared by the reaction of (AlH2Cp*)3 with the corresponding NHCs or by the salt elimination of (NHC)∙GaH2I with KCp*. The gallane adducts decompose at higher temperatures with reductive elimination of Cp*H and formation of Cp*GaI. . The reductive elimination is preferred for sterically demanding NHCs (Dipp2Im > iPr2ImMe > Me2ImMe). In addition, NHC ring expansion of the backbone saturated carbene Dipp2ImH was observed for the reaction of the NHC with (AlH2Cp*)3, which led to (RER-Dipp2ImHH2)AlCp*. Furthermore, the reactivity of the adducts (NHC)∙Cp*EH2 (E = Al, Ga) towards cAACMe was investigated. The reaction of the alane adducts stabilized by the sterically more demanding NHCs iPr2ImMe and Dipp2Im afforded the exceptionally stable insertion product (cAACMeH)Cp*AlH V-10 with liberation of the NHC. The reaction of the gallium hydrides (NHC)∙Cp*GaH2 with cAACMe led to the reductive elimination of cAACMeH2 and formation of Cp*GaI.
A variety of neutral and cationic carbene-stabilized alanes and gallanes are presented in this work. The introduction of electronegative π-donor substituents (Cl-, I-, OR-, NR2-) and the investigations on the thermal stability of these compounds led to the conclusion that the stability of alanes and gallanes increased significantly by such a substitution. Investigations on the reactivity of the NHC adducts towards cAACMe resulted in various insertion products of the carbene into the Al-H or Ga-H bonds and the first cAACMe stabilized dichlorogallane was isolated. Furthermore, a first proof was provided that carbenes can be used specifically for the (formal) reduction of group 13 hydrides of the higher homologues. Thus, the synthesis of Cp*GaI from the reaction of (NHC)∙Cp*GaH2 with cAACMe was developed. In the future, this reaction pathway could be of interest for the preparation of other low-valent compounds of aluminium and gallium.
The Myb-MuvB (MMB) complex plays an essential role in the time-dependent transcriptional activation of mitotic genes. Recently, our laboratory identified a novel crosstalk between the MMB-complex and YAP, the transcriptional coactivator of the Hippo pathway, to coregulate a subset of mitotic genes (Pattschull et al., 2019). Several genetic studies have shown that the Hippo-YAP pathway is essential to drive cardiomyocyte proliferation during cardiac development (von Gise et al., 2012; Heallen et al., 2011; Xin et al., 2011). However, the exact mechanisms of how YAP activates proliferation of cardiomyocytes is not known. This doctoral thesis addresses the physiological role of the MMB-Hippo crosstalk within the heart and characterizes the YAP-B-MYB interaction with the overall aim to identify a potent inhibitor of YAP.
The results reported in this thesis indicate that complete loss of the MMB scaffold protein LIN9 in heart progenitor cells results in thinning of ventricular walls, reduced cardiomyocyte proliferation and early embryonic lethality. Moreover, genetic experiments using mice deficient in SAV1, a core component of the Hippo pathway, and LIN9-deficient mice revealed that the correct function of the MMB complex is critical for proliferation of cardiomyocytes due to Hippo-deficiency. Whole genome transcriptome profiling as well as genome wide binding studies identified a subset of Hippo-regulated cell cycle genes as direct targets of MMB. By proximity ligation assay (PLA), YAP and B-MYB were discovered to interact in embryonal cardiomyocytes. Biochemical approaches, such as co-immunoprecipitation assays, GST-pulldown assays, and µSPOT-based peptide arrays were employed to characterize the YAP-B-MYB interaction. Here, a PY motif within the N-terminus of B-MYB was found to directly interact with the YAP WW-domains. Consequently, the YAP WW-domains were important for the ability of YAP to drive proliferation in cardiomyocytes and to activate MMB target genes in differentiated C2C12 cells. The biochemical information obtained from the interaction studies was utilized to develop a novel competitive inhibitor of YAP called MY-COMP (Myb-YAP competition). In MY-COMP, the protein fragment of B-MYB containing the YAP binding domain is fused to a nuclear localization signal. Co-immunoprecipitation studies as well as PLA revealed that the YAP-B-MYB interaction is robustly blocked by expression of MY-COMP. Adenoviral overexpression of MY-COMP in embryonal cardiomyocytes suppressed entry into mitosis and blocked the pro-proliferative function of YAP. Strikingly, characterization of the cellular phenotype showed that ectopic expression of MY-COMP led to growth defects, nuclear abnormalities and polyploidization in HeLa cells.
Taken together, the results of this thesis reveal the mechanism of the crosstalk between the Hippo signaling pathway and the MMB complex in the heart and form the basis for interference with the oncogenic activity of the Hippo coactivator YAP.
Obesity-induced diabetes affects over 400 million people worldwide. Obesity is a complex metabolic disease and is associated with several co-morbidities, all of which negatively affect the individual’s quality of life. It is commonly considered that obesity is a result of a positive energy misbalance, as increased food intake and lower expenditure eventually lead to the development of this disease. Moreover, the pathology of obesity is attributed to several genetic and epigenetic factors that put an individual at high risk compared to another. Adipose tissue is the main site of the organism’s energy storage. During the time when the nutrients are available in excess, adipocytes acquire triglycerides, which are released during the time of food deprivation in the process of lipolysis (free fatty acids and glycerol released from adipocytes). Uncontrolled lipolysis is the consequent event that contributes to the development of diabetes and paradoxically obesity. To identify the genetic factors aiming for future therapeutic avenues targeting this pathway, we performed a high-throughput screen and identified the Extracellular-regulated kinase 3 (ERK3) as a hit. We demonstrate that β-adrenergic stimulation stabilizes ERK3 leading to the formation of a complex with the co-factor MAP kinase-activated protein kinase 5 (MK5) thereby driving lipolysis. Mechanistically, we identify a downstream target of the ERK3/MK5 pathway, the transcription factor FOXO1, which promotes the expression of the major lipolytic enzyme ATGL. Finally, we provide evidence that targeted deletion of ERK3 in mouse adipocytes inhibits lipolysis, but elevates energy dissipation, promoting lean phenotype and ameliorating diabetes. Moreover, we shed the light on our pharmacological approach in targeting ERK3/MK5 pathways using MK5 specific inhibitor. Already after 1 week of administering the inhibitor, mice showed signs of improvement of their metabolic fitness as showed here by a reduction in induced lipolysis and the elevation in the expression of thermogenic genes. Taken together, our data suggest that targeting the ERK3/MK5 pathway, a previously unrecognized signaling axis in adipose tissue, could be an attractive target for future therapies aiming to combat obesity-induced diabetes.
This thesis is devoted to a theoretical and numerical investigation of methods to solve open-loop non zero-sum differential Nash games. These problems arise in many applications, e.g., biology, economics, physics, where competition between different agents appears. In this case, the goal of each agent is in contrast with those of the others, and a competition game can be interpreted as a coupled optimization problem for which, in general, an optimal solution does not exist. In fact, an optimal strategy for one player may be unsatisfactory for the others. For this reason, a solution of a game is sought as an equilibrium and among the solutions concepts proposed in the literature, that of Nash equilibrium (NE) is the focus of this thesis. The building blocks of the resulting differential Nash games are a dynamical model with different control functions associated with different players that pursue non-cooperative objectives. In particular, the aim of this thesis is on differential models having linear or bilinear state-strategy structures. In this framework, in the first chapter, some well-known results are recalled, especially for non-cooperative linear-quadratic differential Nash games. Then, a bilinear Nash game is formulated and analysed. The main achievement in this chapter is Theorem 1.4.2 concerning existence of Nash equilibria for non-cooperative differential bilinear games. This result is obtained assuming a sufficiently small time horizon T, and an estimate of T is provided in Lemma 1.4.8 using specific properties of the regularized Nikaido-Isoda function. In Chapter 2, in order to solve a bilinear Nash game, a semi-smooth Newton (SSN) scheme combined with a relaxation method is investigated, where the choice of a SSN scheme is motivated by the presence of constraints on the players’ actions that make the problem non-smooth. The resulting method is proved to be locally convergent in Theorem 2.1, and an estimate on the relaxation parameter is also obtained that relates the relaxation factor to the time horizon of a Nash equilibrium and to the other parameters of the game. For the bilinear Nash game, a Nash bargaining problem is also introduced and discussed, aiming at determining an improvement of all players’ objectives with respect to the Nash equilibrium. A characterization of a bargaining solution is given in Theorem 2.2.1 and a numerical scheme based on this result is presented that allows to compute this solution on the Pareto frontier. Results of numerical experiments based on a quantum model of two spin-particles and on a population dynamics model with two competing species are presented that successfully validate the proposed algorithms. In Chapter 3 a functional formulation of the classical homicidal chauffeur (HC) Nash game is introduced and a new numerical framework for its solution in a time-optimal formulation is discussed. This methodology combines a Hamiltonian based scheme, with proximal penalty to determine the time horizon where the game takes place, with a Lagrangian optimal control approach and relaxation to solve the Nash game at a fixed end-time. The resulting numerical optimization scheme has a bilevel structure, which aims at decoupling the computation of the end-time from the solution of the pursuit-evader game. Several numerical experiments are performed to show the ability of the proposed algorithm to solve the HC game. Focusing on the case where a collision may occur, the time for this event is determined. The last part of this thesis deals with the analysis of a novel sequential quadratic Hamiltonian (SQH) scheme for solving open-loop differential Nash games. This method is formulated in the framework of Pontryagin’s maximum principle and represents an efficient and robust extension of the successive approximations strategy in the realm of Nash games. In the SQH method, the Hamilton-Pontryagin functions are augmented by a quadratic penalty term and the Nikaido-Isoda function is used as a selection criterion. Based on this fact, the key idea of this SQH scheme is that the PMP characterization of Nash games leads to a finite-dimensional Nash game for any fixed time. A class of problems for which this finite-dimensional game admits a unique solution is identified and for this class of games theoretical results are presented that prove the well-posedness of the proposed scheme. In particular, Proposition 4.2.1 is proved to show that the selection criterion on the Nikaido-Isoda function is fulfilled. A comparison of the computational performances of the SQH scheme and the SSN-relaxation method previously discussed is shown. Applications to linear-quadratic Nash games and variants with control constraints, weighted L1 costs of the players’ actions and tracking objectives are presented that corroborate the theoretical statements.
During infection, bacteria need to adapt to a changing environment and have to endure various stress conditions. Small non-coding RNAs are considered as important regulators of bacterial gene expression and so allow quick adaptations by altering expression of specific target genes. Regulation of gene expression in the human-restricted pathogen Neisseria gonorrhoeae, the causative agent of the sexually transmitted disease gonorrhoea, is only poorly understood. The present study aims a better understanding of gene regulation in N. gonorrhoeae by studying small non-coding RNAs.
The discovery of antisense RNAs for all opa genes led to the hypothesis of asRNA-mediated degradation of out-of-frame opa transcripts. Analysis of asRNA expression revealed a very low abundance of the transcripts and inclusion of another phase-variable gene in the study indicates that the asRNAs are not involved in degradation of out-of-frame transcripts.
This doctoral thesis focuses on the analysis of trans-acting sRNAs. The sibling sRNAs NgncR_162 and NgncR_163 were discovered as post-transcriptional regulators altering expression of genes involved in metabolic processes, amino acid uptake and transcriptional regulation. A more detailed analysis by in silico and transcriptomic approaches showed that the sRNAs regulate a broad variety of genes coding for proteins of central metabolism, amino acid biosynthesis and degradation and several transport processes. Expression levels of the sibling sRNAs depend on the growth phase of the bacteria and on the growth medium. This indicates that NgncR_162 and NgncR_163 are involved in the adaptation of the gonococcal metabolism to specific growth conditions.
This work further initiates characterisation of the sRNA NgncR_237. An in silico analysis showed details on sequence conservation and a possible secondary structure. A combination of in silico target prediction and differential RNA sequencing resulted in the identification of several target genes involved in type IV pilus biogenesis and DNA recombination. However, it was not successful to find induction conditions for sRNA expression. Interestingly, a possible sibling sRNA could be identified that shares the target interaction sequence with NgncR_237 and could therefore target the same mRNAs.
In conclusion, this thesis provides further insights in gene regulation by non-coding RNAs in N. gonorrhoeae by analysing two pairs of sibling sRNAs modulating bacterial metabolism or possibly type IV pilus biogenesis.
It is generally acknowledged that polyfluoroarenes are important fluorinated structural units for various organic molecules, such as pharmaceuticals, agrochemicals, and organic materials. Polyfluorinated aryl alkynes and alcohols are also powerful building blocks in chemical synthesis because of their versatility to be transformed into various useful molecules and also their ubiquity in natural product synthesis. Efficient methods for the synthesis of polyfluorinated aryl alkynes and alcohols are presented in Chapter 2 and Chapter 3. In addition, 3-amino-indoles have found a broad applications in medicinal chemistry as effective anticancer agents, compounds with analgesic properties and can function as potent inhibitors of tubulin polymerization, and agents for the prevention of type II diabetes. A simple method for the synthesis of 3-amino-indoles via the annulation reaction of polyfluorophenylboronates with DMF is reported in Chapter 4.
Chapter 2
In Chapter 2, a mild process for the copper-catalyzed oxidative cross-coupling of electron-deficient polyfluorophenylboronate esters with terminal alkynes (Scheme S-1) is reported. This method displays good functional group tolerance and broad substrate scope, generating cross-coupled alkynyl(fluoro)arene products in moderate to excellent yields. This copper-catalyzed reaction was conducted on a gram scale to generate the corresponding product in good yield (72%).
Scheme S-1. Copper-catalyzed oxidative cross-coupling of terminal alkynes with polyfluorophenylboronate esters.
Based on previous reports and the aforementioned observations, a plausible catalytic cycle for this oxidative cross-coupling reaction is shown in Scheme S-2. The first step involves the addition of an alkynyl anion to Cu leading to the formation of alkynylcopper(II) species B. Subsequent transmetalation between ArFBpin and intermediate B occurs to form intermediate C. The desired product 3a is generated by eductive elimination. Finally, the oxidation of Cu(0) to Cu(II) with DDQ and Ag2O regenerates A to complete the catalytic cycle.
Scheme S-2. Proposed mechanism of copper(II)-catalyzed oxidative cross-coupling between terminal alkynes and polyfluorophenylboronate esters.
Chapter 3
In Chapter 3, A convenient and efficient protocol for the transition metal-free 1,2-addition of polyfluoroaryl boronate esters to aldehydes and ketones is reported, which provides secondary alcohols, tertiary alcohols, and ketones (Scheme S-3). The distinguishing features of this procedure include the employment of commercially available starting materials and the broad scope of the reaction with a wide variety of carbonyl compounds giving moderate to excellent yields.
Scheme S-3. Base-promoted 1,2-addition of polyfluorophenylboronates to aldehydes and ketones.
Control experiments were carried out to gain insight into the reaction mechanism. The reaction of 2a with pentafluorobenzene 5 under standard conditions was examined, yet 3a was not formed in any detectable amounts (Scheme S-4a), indicating that the C-Bpin moiety is essential and deprotonation of the fluoroarene or nucleophilic attack at the fluoroarene by the base is not a plausible pathway. Interestingly, for the standard reaction between 1a and 2a, the yield dropped dramatically if 18-crown-6 ether and K2CO3 were added (Scheme S-4b). This experimental result indicates that the presence of the potassium ion plays a crucial role for the outcome of the reaction. Furthermore, if the reaction of 1a and 2a was performed in the presence of only a catalytic amount of K2CO3 (20 mol%) (Scheme S-4c), reaction rates were reduced, and a week was required to produce 3a in good yield. This finding again indicates that the potassium ion (or the base) plays an important role in the reaction. Substituting ortho-fluorines by ortho-chlorines, using either C6Cl5Bpin 2,6-dichlorophenyl-1-Bpin as substrates, did not yield any product as shown by in situ GCMS studies.
Scheme S-4. Control experiments.
Based on DFT calculations, a mechanism for the 1,2-addition of polyfluorophenylboronates to aryl aldehydes in the presence of K2CO3 as base is proposed, as shown in Scheme S-5. K2CO3 interacts with the Lewis-acidic Bpin moiety of substrate 1 to generate base adduct A, which weakens the carbon-boron bond and ultimately cleaves the BC bond along with attachment of a potassium cation to the aryl group. The resulting ArF- anion adduct B undergoes nucleophilic attack at the aldehyde carbon atom of substrate 2 to generate methanolate C. The methanolate oxygen atom then attacks the electrophilic Bpin group to obtain compound D. Transfer of K2CO3 from intermediate D to the boron atom of the more Lewis-acidic polyfluorophenyl-Bpin 1 finally closes the cycle and regenerates complex A. Thus, the primary reaction product is the O-borylated addition product E, which was detected by HRMS and NMR spectroscopy for the perfluorinated derivative.
Scheme S-5. Proposed mechanism of the 1,2-addition of polyfluorophenylboronates to aldehydes and ketones.
Chapter 4
Chapter 4 presents a novel protocol for the transition metal-free addition and annulation of polyfluoroarylboronate esters to DMF, which provides 3-aminoindoles and tertiary amines in moderate to excellent yields (Scheme S-6).
Scheme S-6. Annulation and addition reactions of polyfluorophenylboronates with DMF.
While exploring the application of this strategy in synthesis, perfluorophenylBpin reacted smoothly with ethynylarenes and DMF to afford propargylamines with moderate to excellent yields (Scheme S-7).
Scheme S-7. Three-component cross-coupling reaction for the synthesis of propargylamines.
Within three self-contained studies, this dissertation studies the impact and interactions between different macroeconomic policy measures in the context of financial markets empirically and quantitatively. The first study of this dissertation sheds light on the financial market effects of unconventional central bank asset purchase programs in the Eurozone, in particular sovereign bond asset purchase programs. The second study quantifies the direct implications of unconventional monetary policy on decisions by German public debt management regarding the maturity structure of gross issuance. The third study provides novel evidence on the role of private credit markets in the propagation of public spending toward private consumption in the U.S. economy. Across these three studies a set of different time-series econometric methods is applied including error correction models and event study frameworks to analyze contemporaneous interactions in financial and macroeconomic data in the context of unconventional monetary policy, as well as vector auto regressions (VARs) and local projections to trace the dynamic consequences of macroeconomic policies over time.
Significant advances in fluorescence imaging techniques enable life scientists today to gain insights into biological systems at an unprecedented scale. The interpretation of image features in such bioimage datasets and their subsequent quantitative analysis is referred to as bioimage analysis. A substantial proportion of bioimage analyses is still performed manually by a human expert - a tedious process that is long known to be subjective. Particularly in tasks that require the annotation of image features with a low signal-to-noise ratio, like in fluorescence images of tissue samples, the inter-rater agreement drops. However, like any other scientific analysis, also bioimage analysis has to meet the general quality criteria of quantitative research, which are objectivity, reliability, and validity. Thus, the automation of bioimage analysis with computer-aided approaches is highly desirable. Albeit conventional hard-coded algorithms are fully unbiased, a human user has to set its respective feature extraction parameters. Thus, also these approaches can be considered subjective.
Recently, deep learning (DL) has enabled impressive advances in computer vision research. The predominant difference between DL and conventional algorithms is the capability of DL models to learn the respective task on base of an annotated training dataset, instead of following user-defined rules for feature extraction. This thesis hypothesized that DL can be used to increase the objectivity, reliability, and validity of bioimage analyses, thus going beyond mere automation. However, in absence of ground truth annotations, DL models have to be trained on manual and thus subjective annotations, which could cause the model to incorporate such a bias. Moreover, model training is stochastic and even training on the same data could result in models with divergent outputs. Consequently, both the training on subjective annotations and the model-to-model variability could impair the quality of DL-based bioimage analyses. This thesis systematically assessed the impacts of these two limitations experimentally by analyzing fluorescence signals of a protein called cFOS in mouse brain sections. Since the abundance of cFOS correlates with mouse behavior, behavioral analyses could be used for cross-validation of the bioimage analysis results. Furthermore, this thesis showed that pooling the input of multiple human experts during model training and integration of multiple trained models in a model ensemble can mitigate the impact of these limitations. In summary, the present study establishes guidelines for how DL can be used to increase the general quality of bioimage analyses.
This doctoral thesis is part of a research project on the development of the cognitive compre-hension of film at Würzburg University that was funded by the German Research Foundation (Deutsche Forschungsgemeinschaft) between 2013 and 2019 and awarded to Gerhild Nied-ing. That project examined children’s comprehension of narrative text and its development in illustrated versus non-illustrated formats. For this purpose, van Dijk and Kintsch’s (1983) tri-partite model was used, according to which text recipients form text surface and textbase rep-resentations and construct a situation model. In particular, predictions referring to the influ-ence of illustrations on these three levels of text representation were derived from the inte-grated model of text and picture comprehension (ITPC; Schnotz, 2014), which holds that text-picture units are processed on both text-based (descriptive) and picture-based (depictive) paths. Accordingly, illustrations support the construction of a situation model. Moreover, in line with the embodied cognition account (e.g., Barsalou, 1999), it was assumed that the situa-tion model is grounded in perception and action; text recipients mentally simulate the situation addressed in the text through their neural systems related to perception (perceptual simulation) and action (motor resonance). Therefore, the thesis also examines whether perceptual simula-tion takes place during story reception, whether it improves the comprehension of illustrated stories, and whether motor resonance is related to the comprehension of text accompanied by dynamic illustrations. Finally, predictions concerning the development of comprehending illus-trated text were made in line with Springer’s (2001) hypotheses according to which younger children, compared with older children and adults, focus more on illustrations during text comprehension (perceptual boundedness) and use illustrations for the development of cogni-tive skills (perceptual support).
The first research question sought to validate the tripartite model in the context of children’s comprehension of narrative text, so Hypothesis 1 predicted that children yield representations of the text surface, the textbase, and the situation model during text reception. The second research question comprised the assumptions regarding the impact of illustrations on text comprehension. Accordingly, it was expected that illustrations improve the situation model (Hypothesis 2a), especially when they are processed before their corresponding text passages (Hypothesis 2b). Both hypotheses were derived from the ITPC and the assumption that per-ceptual simulation supports the situation model. It was further predicted that dynamic illustra-tions evoke more accurate situation models than static ones (Hypothesis 2c); this followed from the assumption that motor resonance supports the situation model. In line with the ITPC, it was assumed that illustrations impair the textbase (Hypothesis 2d), especially when they are presented after their corresponding text passages (Hypothesis 2e). In accordance with earlier results, it was posited that illustrations have a beneficial effect for the text surface (Hypothesis 2f). The third research question addressed the embodied approach to the situation model. Here, it was assumed that perceptual simulation takes place during text reception (Hypothesis 3a) and that it is more pronounced in illustrated than in non-illustrated text (Hypothesis 3b); the latter hypothesis was related to a necessary premise of the assumption that perceptual sim-ulation improves the comprehension of illustrated text. The fourth research question was relat-ed to perceptual boundedness and perceptual support and predicted age-related differences; younger children were expected to benefit more from illustrations regarding the situation model (Hypothesis 4a) and to simulate vertical object movements in a more pronounced fash-ion (Hypothesis 4b) than older children. In addition, Hypothesis 4c held that perceptual simu-lation is more pronounced in younger children particularly when illustrations are present.
Three experiments were conducted to investigate these hypotheses. Experiment 1 (Seger, Wannagat, & Nieding, submitted).compared the tripartite representations of written text without illustrations, with illustrations presented first, and with illustrations presented after their corresponding sentences. Students between 7 and 13 years old (N = 146) took part. Ex-periment 2 (Seger, Wannagat, & Nieding, 2019) investigated the tripartite representations of auditory text, audiovisual text with static illustrations, and audiovisual text with dynamic il-lustrations among children in the same age range (N = 108). In both experiments, a sentence recognition method similar to that introduced by Schmalhofer and Glavanov (1986) was em-ployed. This method enables the simultaneous measurement of all three text representations. Experiment 3 (Seger, Hauf, & Nieding, 2020) determined the perceptual simulation of vertical object movements during the reception of auditory and audiovisual narrative text among chil-dren between 5 and 11 years old and among adults (N = 190). For this experiment, a picture verification task based on Stanfield and Zwaan’s (2001) paradigm and adapted from Hauf (2016) was used.
The first two experiments confirmed Hypothesis 1, indicating that the tripartite model is appli-cable to the comprehension of auditory and written narrative text among children. A benefi-cial effect of illustrations to the situation model was observed when they were presented syn-chronously with auditory text (Hypotheses 2a), but not when presented asynchronously with written text (Hypothesis 2b), so the ITPC is partly supported on this point. Hypothesis 2c was rejected, indicating that motor resonance does not make an additional contribution to the comprehension of narrative text with dynamic illustrations. Regarding the textbase, a general negative effect of illustrations was not observed (Hypothesis 2d), but a specific negative effect of illustrations that follow their corresponding text passages was seen (Hypothesis 2e); the latter result is also in line with the ITPC. The text surface (Hypothesis 2f) appears to benefit from illustrations in auditory but not written text. The results obtained in Experiment 3 sug-gest that children and adults perceptually simulate vertical object movements (Hypothesis 3a), but there appears to be no difference between auditory and audiovisual text (Hypothesis 3b), so there is no support for a functional relationship between perceptual simulation and the situ-ation model in illustrated text. Hypotheses 4a–4c were investigated in all three experiments and did not receive support in any of them, which indicates that representations of illustrated and non-illustrated narrative text remain stable within the age range examined here.
These days, treatment of melanoma patients relies on targeted therapy with BRAF/MEK inhibitors and on immunotherapy. About half of all patients initially respond to existing therapies. Nevertheless, the identification of alternative therapies for melanoma patients with intrinsic or acquired resistance is of great importance. In melanoma, antioxidants play an essential role in the maintenance of the redox homeostasis. Therefore, disruption of the redox homeostasis is regarded as highly therapeutically relevant and is the focus of the present work.
An adequate supply of cysteine is essential for the production of the most important intracellular antioxidants, such as glutathione. In the present work, it was investigated whether the depletion of cysteine and glutathione is therapeutically useful. Depletion of glutathione in melanoma cells could be achieved by blocking cysteine supply, glutathione synthesis, and NADPH regeneration. As expected, this led to an increased level of reactive oxygen species (ROS). Surprisingly, however, these changes did not impair the proliferation and survival of the melanoma cells. In contrast, glutathione depletion led to cellular reprogramming which was characterized by the induction of mesenchymal genes and the repression of differentiation markers (phenotypic switch). This was accompanied by an increased migration and invasion potential which was favored by the induction of the transcription factor FOSL1. To study in vivo reprogramming, Gclc, the first and rate-limiting enzyme in glutathione synthesis, was knocked out by CRISPR/Cas9 in murine melanoma cells. The cells were devoid of glutathione, but were fully viable and showed a phenotypic switch, the latter only in MITF-expressing B16F1 cells and not in MITF-deficient D4M3A.781 cells. Following subcutaneous injection into immunocompetent C57BL/6 mice, Gclc knockout B16F1 cells grew more aggressively and resulted in an earlier tumor onset than B16F1 control cells.
In summary, this work demonstrates that inhibition of cysteine supply and thus, glutathione synthesis leads to cellular reprogramming in melanoma. In this context, melanoma cells show metastatic capabilities, promoting a more aggressive form of the disease.
We employ the AdS/CFT correspondence and hydrodynamics to analyze the transport properties of \(2+1\) dimensional electron fluids. In this way, we use theoretical methods from both condensed matter and high-energy physics to derive tangible predictions that are directly verifiable in experiment.
The first research topic we consider is strongly-coupled electron fluids. Motivated by early results by Gurzhi on the transport properties of weakly coupled fluids, we consider whether similar properties are manifest in strongly coupled fluids. More specifically, we focus on the hydrodynamic tail of the Gurzhi effect: A decrease in fluid resistance with increasing temperature due to the formation of a Poiseuille flow of electrons in the sample. We show that the hydrodynamic tail of the Gurzhi effect is also realized in strongly coupled and fully relativistic fluids, but with modified quantitative features. Namely, strongly-coupled fluids always exhibit a smaller resistance than weakly coupled ones and are, thus, far more efficient conductors. We also suggest that the coupling dependence of the resistance can be used to measure the coupling strength of the fluid. In view of these measurements, we provide analytical results for the resistance as a function of the shear viscosity over entropy density \(\eta/s\) of the fluid. \(\eta/s\) is itself a known function of the coupling strength in the weak and infinite coupling limits.
In further analysis for strongly-coupled fluids, we propose a novel strongly coupled Dirac material based on a kagome lattice, Scandium-substituted Herbertsmithite (ScHb). The large coupling strength of this material, as well as its Dirac nature, provides us with theoretical and experimental access to non-perturbative relativistic and quantum critical physics. A highly suitable method for analyzing such a material's transport properties is the AdS/CFT correspondence. Concretely, using AdS/CFT we derive an estimate for ScHb's \(\eta/s\) and show that it takes a value much smaller than that observed in weakly coupled materials. In turn, the smallness of \(\eta/s\) implies that ScHb's Reynolds number, \(Re\), is large. In fact, \(Re\) is large enough for turbulence, the most prevalent feature of fluids in nature, to make its appearance for the first time in electronic fluids.
Switching gears, we proceed to the second research topic considered in this thesis: Weakly coupled parity-breaking electron fluids. More precisely, we analyze the quantitative and qualitative changes to the classical Hall effect, for electrons propagating hydrodynamically in a lead. Apart from the Lorentz force, a parity-breaking fluid's motion is also impacted by the Hall-viscous force; the shear-stress force induced by the Hall-viscosity. We show that the interplay of these two forces leads to a hydrodynamic Hall voltage with non-linear dependence on the magnetic field. More importantly, the Lorentz and Hall-viscous forces become equal at a non-vanishing magnetic field, leading to a trivial hydrodynamic Hall voltage. Moreover, for small magnetic fields we provide analytic results for the dependence of the hydrodynamic Hall voltage on all experimentally-tuned parameters of our simulations, such as temperature and density. These dependences, along with the zero of the hydrodynamic Hall voltage, are distinct features of hydrodynamic transport and can be used to verify our predictions in experiments.
Last but not least, we consider how a distinctly electronic property, spin, can be included into the hydrodynamic framework. In particular, we construct an effective action for non-dissipative spin hydrodynamics up to first order in a suitably defined derivative expansion. We also show that interesting spin-transport effects appear at second order in the derivative expansion. Namely, we show that the fluid's rotation polarizes its spin. This is the hydrodynamic manifestation of the Barnett effect and provides us with an example of hydrodynamic spintronics.
To conclude this thesis, we discuss several possible extensions of our research, as well as proposals for research in related directions.
Expression of the MYC oncoprotein, which binds the DNA at promoters of most transcribed genes, is controlled by growth factors in non-tumor cells, thus stimulating cell growth and proliferation.
Here in this thesis, it is shown that MYC interacts with SPT5, a subunit of the RNA polymerase II (Pol II) elongation factor DSIF. MYC recruits SPT5 to promoters of genes and is required for its association with Pol II. The transfer of SPT5 is mediated by CDK7 activity on TFIIE, which evicts it from Pol II and allows SPT5 to bind Pol II.
MYC is required for fast and processive transcription elongation, consistent with known functions of SPT5 in yeast. In addition, MYC increases the directionality of promoters by stimulating sense transcription and by suppressing the synthesis of antisense transcripts.
The results presented in this thesis suggest that MYC globally controls the productive assembly of Pol II with general elongation factors to form processive elongation complexes in response to growth-factor stimulation of non-tumour cells. However, MYC is found to be overexpressed in many tumours, and is required for their development and progression.
In this thesis it was found that, unexpectedly, such overexpression of MYC does not further enhance transcription but rather brings about squelching of SPT5. This reduces the processivity of Pol II on selected set of genes that are known to be repressed by MYC, leading to a decrease in growth-suppressive gene transcription and uncontrolled tumour growth
The implantation of any foreign material into the body automatically starts an immune reaction that serves as the first, mandatory step to regenerate tissue. The course of this initial immune reaction decides on the fate of the implant: either the biomaterial will be integrated into the host tissue to subsequently fulfill its intended function (e.g., tissue regeneration), or it will be repelled by fibrous encapsulation that determines the implant failure. Especially neutrophils and macrophages play major roles during this inflammatory response and hence mainly decide on the biomaterial's fate. For clinically relevant tissue engineering approaches, biomaterials may be designed in shape and morphology as well as in their surface functionality to improve the healing outcome, but also to trigger stem cell responses during the subsequent tissue regeneration phase.
The main focus of this thesis was to unravel the influence of scaffold characteristics, including scaffold morphology and surface functionality, on primary human innate immune cells (neutrophils and macrophages) and human mesenchymal stromal cells (hMSCs) to assess their in vitro immune response and tissue regeneration capacity, respectively. The fiber-based constructs were produced either via melt electrowriting (MEW), when the precise control over scaffold morphology was required, or via solution electrospinning (ES), when the scaffold design could be neglected. All the fiber-based scaffolds used throughout this thesis were composed of the polymer poly(ε caprolactone) (PCL).
A novel strategy to model and alleviate the first direct cell contact of the immune system with a peptide-bioactived fibrous material was presented in chapter 3 by treating the material with human neutrophil elastase (HNE) to imitate the neutrophil attack. The main focus of this study was put on the effect of HNE towards an RGDS-based peptide that was immobilized on the surface of a fibrous material to improve subsequent L929 cell adhesion. The elastase efficiently degraded the peptide-functionality, as evidenced by a decreased L929 cell adhesion, since the peptide integrated a specific HNE-cleavage site (AAPV-motif). A sacrificial hydrogel coating based on primary oxidized hyaluronic acid (proxHA), which dissolved within a few days after the neutrophil attack, provided an optimal protection of the peptide-bioactivated fibrous mesh, i.e, the hydrogel alleviated the neutrophil attack and largely ensured the biomaterial's integrity. Thus, according to these results, a means to protect the biomaterial is required to overcome the neutrophil attack.
Chapter 4 was based on the advancement of melt electrowriting (MEW) to improve the printing resolution of MEW scaffolds in terms of minimal inter-fiber distances and a concomitant high stacking precision. Initially, to gain a better MEW understanding, the influence of several parameters, including spinneret diameter, applied pressure, and collector velocity on mechanical properties, crystallinity, fiber diameter and fiber surface morphology was analyzed. Afterward, innovative MEW designs (e.g., box-, triangle-, round , and wall-shaped scaffolds) have been established by pushing the printing parameters to their physical limits. Further, the inter-fiber distance within a standardized box-structured scaffold was successfully reduced to 40 µm, while simultaneously a high stacking precision was maintained. In collaboration with a co-worker of my department (Tina Tylek, who performed all cell-based experiments in this study), these novel MEW scaffolds have been proven to facilitate human monocyte-derived macrophage polarization towards the regenerative M2 type in an elongation-driven manner with a more pronounced effect with decreasing pore sizes.
Finally, a pro-adipogenic platform for hMSCs was developed in chapter 5 using MEW scaffolds with immobilized, complex ECM proteins (e.g., human decellularized adipose tissue (DAT), laminin (LN), and fibronectin (FN)) to test for the adipogenic differentiation potential in vitro. Within this thesis, a special short-term adipogenic induction regime enabled to more thoroughly assess the intrinsic pro-adipogenic capacity of the composite biomaterials and prevented any possible masking by the commonly used long-term application of adipogenic differentiation reagents. The scaffolds with incorporated DAT consistently showed the highest adipogenic outcome and hence provided an adipo-inductive microenvironment for hMSCs, which holds great promise for applications in soft tissue regeneration.
Future studies should combine all three addressed projects in a more in vivo-related manner, comprising a co-cultivation setup of neutrophils, macrophages, and MSCs. The MEW-scaffold, particularly due to its ability to combine surface functionality and adjustable morphology, has been proven to be a successful approach for wound healing and paves the way for subsequent tissue regeneration.
The aim of the first part of this thesis was to investigate (R,R)-PBI as a model system for polymorphism at its origin by a supramolecular approach. The pathway complexity of (R,R)-PBI was fine-tuned by experimental parameters such as solvent, temperature and concentration to make several supramolecular polymorphs accessible. Mechanistic and quantum chemical studies on the kinetics and thermodynamics of the supramolecular polymerization of (R,R)-PBI were conducted to shed light on the initial stages of polymorphism. The second part of this work deals with mechanistic investigations on the supramolecular polymerization of the racemic mixture of (R,R)- and (S,S)-PBI with regard to homochiral and heterochiral aggregation leading to conglomerates and a racemic supramolecular polymer, respectively.
Peripheral neuropathies can severely affect patients. Causes for the disease are diverse but can be classified into two main groups, acquired and hereditary. Examples for these two types are chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Charcot-Marie-Tooth disease type 1A (CMT1A). CIDP has an estimated prevalence of about 1-9:100 000. In this pathogenetically hetereo- geneous patient group about 5-10% show auto-antibodies against the node of Ranvier and present with distinct symptoms. Treatment with rituximab - a monoclonal antibody that deletes CD20 + B cells - has been shown to be effective in a majority of auto-antibody as- sociated CIDP cases. This suggests that B cells and the produced auto-antibodies might be pathogenic. Previous studies delivered evidence that auto-antibodies alone can induce nerve damage. In this study, the aim was to investigate the pathomechanism of auto-antibodies in vivo and their exact origin: For the analysis of the pathogenicity of auto-antibodies, passive transfer experiments on Lewis rats were performed with whole IgG from a patient with anti-contactin-1 (CNTN1) IgG4 auto-antibodies. IgG was infused through an intrathe- cal catheter targeting the thoracic/lumbar region of the spine over a long-term, 3-week period. In a previous study of our group, the IgG from the same patient has been re- ported to have mild pathogenic effects when applied intraneurally into the sciatic nerve of Lewis rats. In this study however, binding of auto-antibodies to nerve roots could not be detected. Neither evaluation of electrophysiological properties after the injection period nor motor and sensory skills tested throughout the injection period showed differences when compared to animals infused with control IgG. This suggests that in the chronic intrathecal protocol anti-CNTN1 auto-antibodies did not have a pathogenic effect. In peripheral blood, four B cell subsets capable to produce antibodies were previously described: memory B cells, plasmablasts (PBs), B1 cells and CD20 + CD38 hi cells. For the identification of the B cell subsets that produce auto-antibodies, purification and sort protocols as well as an enzyme-linked immuno spot (ELISpot) assay for IgG and IgM were established successfully. Since unstimulated B cell subsets produced very small amounts of IgG and IgM, peripheral blood mononuclear cells (PBMCs) were stimulated with IL-2 and R848 for 72 h prior to sorting. While the memory B cell frequency decreased after stimulation, the frequency of CD20 + CD38 hi cells increased and the overall number of antibody-secreting cells was increased. When stimulating patient PBMCs for 10 days though, detection of anti-neurofascin-155 (NF155) auto-antibodies in supernatants by enzyme-linked immunosorbent assay (ELISA) was possible in two out of three patient samples. Even though cell sorting was feasible after 10 days of stimulation, detection of auto-antibodies could not be accomplished using antigen-specific ELISpot. Although the implementation of the cell sorting and purification protocol was successful, further adjustments of the antigen-specific ELISpot need to be performed. However, we could show that after 10 days of stimulation auto-antibody detection is possible by ELISA which helps to pre-screen if patient PBMC contain auto-reactive B cells. CMT1A has an estimated prevalence of 1:5000 and is caused by a duplication of the peripheral myelin protein 22 kDa (PMP22) gene. Patients suffer from distal weakness and muscle wasting leading even to wheelchair-dependency in some cases. Although different treatment options for CMT1A have been tested in previous clinical trials, none of them have been successful. In this study, the aim was to identify objective and reproducible outcome measures that assess the actual nerve damage in a large cohort of CMT1A patients by analyzing a series of parameters. Glabrous skin samples were collected from 48 CMT1A, 7 CIDP and 16 small fiber neuropathy patients and 45 healthy controls. 40-µm cryosections from the lateral part of the index finger were double-labeled using immunoflu- orescence to investigate cutaneous innervation. The disease severity which was assessed using the Charcot-Marie-Tooth Neuropathy Score version 2 (CMTNSv2) and ranged between mild to severe (3-27) correlated with age in CMT1A patients. Furthermore, the intraepidermal nerve fiber density (IENFD) was reduced in CMT1A patients in comparison to controls and correlated negatively with the disease severity. In controls however, the IENFD correlated inversely with age. Meissner corpuscle density tended to be reduced and correlated inversely with age in CMT1A patients. This was not observed in healthy controls though. Compared to controls, Merkel cell density was also reduced in CMT1A, while the fraction of denervated Merkel cell was increased and correlated with age. Further differences were revealed concerning the node of Ranvier. Paranodes were shortened and the fraction of long nodes was decreased in CMT1A patients compared to controls. These data suggest that the IENFD, the Meissner corpuscle and Merkel cell densities are possible candidates for outcome measures as they are associated with disease severity or age of patients. However, a reliable statement about the suitability as a marker for disease progression can not be made in this study since only six CMT1A patients agreed to give a follow-up biopsy two years later.
Among mental disorders, panic disorder (PD) is one of the most common anxiety disorders characterized by recurring and unexpected episodes of extreme fear i.e. panic attacks. PD displays lifetime prevalence rates in the general population between 2.1-4.7 % and in about 30 to 40 % occurs comorbid with major depressive disorder (MDD). Differential methylation levels of the monoamine oxidase A (MAOA) gene have previously been associated with the etiology of both PD and MDD. The TGFB-Inducible Early Growth Response Protein 2 (TIEG2; alias KLF11), an activating transcription factor of the MAOA gene, has been reported to be increased in MDD, but has not yet been investigated in PD on any level.
Therefore, in an attempt to further define the role of an impaired TIEG2-MAOA pathway in anxiety and affective disorders, in the present thesis TIEG2 promoter DNA methylation was analyzed in two independent samples of I) PD patients with or without comorbid MDD in a case/control design and II) MDD patients with and without anxious depression. Additionally, in PD patients of sample I), TIEG2 methylation was correlated with Beck Depression Inventory (BDI-II) scores. Finally, in a third independent healthy control sample, correlation of TIEG2 promoter methylation levels with Anxiety Sensitivity Index (ASI) scores as a PD-related measure was analyzed.
No overall association of TIEG2 promoter methylation with PD was detected. However, PD patients with comorbid MDD showed significant TIEG2 hypomethylation compared to PD patients without comorbid MDD (p=.008) as well as to healthy controls (p=.010). In addition, MDD patients without anxious features displayed a statistical trend in decreased TIEG2 methylation in comparison to MDD patients with anxious depression (p=.052). Furthermore, TIEG2 methylation was negatively correlated with BDI-II scores in PD patients (p=.013) and positively correlated with ASI scores in the healthy control sample (p=.043).
In sum, the current study suggests TIEG2 promoter hypomethylation as a potential epigenetic marker of MDD comorbidity in PD or of non-anxious depression, respectively. If replicated and verified in future studies, altered TIEG2 methylation might therefore represent a differential pathomechanism of anxiety and mood disorders.
This thesis focused on the influence of the underlying crystal structure and hence, of the mutual molecular orientation, on the excited states in ordered molecular aggregates. For this purpose, two model systems have been investigated. In the prototypical donor-acceptor complex pentacene-perfluoropentacene (PEN-PFP) the optical accessibility of the charge transfer state and the possibility to fabricate highly defined interfaces by means of single crystal templates enabled a deep understanding of the spatial anisotropy of the charge transfer state formation. Transferring the obtained insights to the design of prototypical donor-acceptor devices, the importance of interface control to minimize the occurrence of charge transfer traps and thereby, to improve the device performance, could be demonstrated. The use of zinc phthalocyanine (ZnPc) allowed for the examination of the influence of molecular packing on the excited electronic states without a change in molecular species by virtue of its inherent polymorphism. Combining structural investigations, optical absorption and emission spectroscopy, as well as Franck-Condon modeling of emission spectra revealed the nature of the optical excited state emission in relation to the structural \(\alpha \) and \(\beta \) phase over a wide temperature range from 4 K to 300 K. As a results, the phase transition kinetics of the first order \(\alpha \rightarrow \beta\) phase transition were characterized in depth and applied to the fabrication of prototypical dual luminescent OLEDs.
Two-dimensional triangular lattices of group IV adatoms on semiconductor substrates provide a rich playground for the investigation of Mott-Hubbard physics. The possibility to combine various types of adatoms and substrates makes members of this material class versatile model systems to study the influence of correlation strength, band filling and spin-orbit coupling on the electronic structure - both experimentally and with dedicated many-body calculation techniques. The latter predict exotic ground states such as chiral superconductivity or spin liquid behavior for these frustrated lattices, however, experimental confirmation is still lacking. In this work, three different systems, namely the \(\alpha\)-phases of Sn/SiC(0001), Pb/Si(111), and potassium-doped Sn/Si(111) are investigated with scanning tunneling microscopy and photoemission spectroscopy in this regard. The results are potentially relevant for spintronic applications or quantum computing.
For the novel group IV triangular lattice Sn/SiC(0001), a combined experimental and theoretical study reveals that the system features surprisingly strong electronic correlations because they are boosted by the substrate through its partly ionic character and weak screening capabilities. Interestingly, the spectral function, measured for the first time via angle-resolved photoemission, does not show any additional superstructure beyond the intrinsic \(\sqrt{3} \times \sqrt{3} R30^{\circ}\) reconstruction, thereby raising curiosity regarding the ground-state spin pattern.
For Pb/Si(111), preceding studies have noted a phase transition of the surface reconstruction from \(\sqrt{3} \times \sqrt{3} R30^{\circ}\) to \(3 \times 3\) at 86 K. In this thesis, investigations of the low-temperature phase with high-resolution scanning tunneling microscopy and spectroscopy unveil the formation of a charge-ordered ground state. It is disentangled from a concomitant structural rearrangement which is found to be 2-up/1-down, in contrast to previous predictions. Applying an extended variational cluster approach, a phase diagram of local and nonlocal Coulomb interactions is mapped out. Based on a comparison of theoretical spectral functions with scattering vectors found via quasiparticle interference, Pb/Si(111) is placed in said phase diagram and electronic correlations are found to be the driving force of the charge-ordered state.
In order to realize a doped Mott insulator in a frustrated geometry, potassium was evaporated onto the well-known correlated Sn/Si(111) system. Instead of the expected insulator-to-metal transition, scanning tunneling spectroscopy data indicates that the electronic structure of Sn/Si(111) is only affected locally around potassium atoms while a metallization is suppressed. The potassium atoms were found to be adsorbed on empty \(T_4\) sites of the substrate which eventually leads to the formation of two types of K-Sn alloys with a relative potassium content of 1/3 and 1/2, respectively. Complementary measurements of the spectral function via angle-resolved photoemission reveal that the lower Hubbard band of Sn/Si(111) gradually changes its shape upon potassium deposition. Once the tin and potassium portion on the surface are equal, this evolution is complete and the system can be described as a band insulator without the need to include Coulomb interactions.
CD4+Foxp3+ Tregs can be induced in vitro by TGF-b stimulation. Here, CNS1 deficient CD4+ T cells were found to show compromised Foxp3 upregulation in vitro compared to CNS1 WT CD4+ T cells. Moreover, we could demonstrate that antigen-specific CD4+Foxp3+ Tregs can be induced in vivo by tolerogenic antigen stimulation. Parenteral application of agonist BDC2.5 mimetope induced Foxp3 expression in CD4+ BDC2.5 tg cells. We could show that induction of Foxp3 expression by tolerogenic peptide stimulation is impaired in CNS1 deficient CD4+ BDC2.5 tg cells compared to CNS1 WT CD4+ BDC2.5 tg controls. These results indeed indicate that in vivo induced Tregs share mechanistic characteristics with naturally occurring pTregs.
Additional in vivo experiments with blocking monoclonal anti-TGF-b demonstrated that high dosage TGF-b blockade abrogated peptide-induced Foxp3 expression in CNS1 WT BDC2.5 tg CD4+ cells, akin to what is seen for impaired Foxp3 upregulation in peptide-stimulated CNS1 KO BDC2.5 tg CD4+ cells without anti-TGF-b-treatment.
Adoptive transfer of CD4+CD25- T cells in T cell deficient recipients dramatically increased CD4+Foxp3+ Treg frequencies in both CNS1 WT CD4+ and CNS1 KO CD4+ donor cells. Despite an initially lower increase in Foxp3 expression in CNS1 KO donor cells compared to CNS1 WT donor cells early after transfer, in this setting impaired Treg induction in CNS1 deficient cells was not preserved over time. Consequently, diabetes onset and progression were indistinguishable between mice that received CNS1 WT or CNS1 KO donor cells. Additional Foxp3 induction by peptide stimulation of immunodeficient recipients after transfer of CNS1 WT BDC2.5. tg or CNS1 KO BDC2.5 tg donor cells was not detectable.
Platelets, small anucleate cell fragments in the blood stream, derive from large precursor cells, so-called megakaryocytes (MK) residing in the bone marrow (BM). In addition to their role in wound healing, platelets have been shown to play a significant role during inflammatory bleeding. Above all, the immunoreceptor tyrosine-based activation motif (ITAM) receptors GPVI as well as CLEC-2 have been identified as main regulators of vascular integrity.
In addition to ITAM-bearing receptors, our group identified GPV as another potent regulator of hemostasis and thrombosis. Surprisingly, concomitant lack of GPV and CLEC-2 deteriorated blood-lymphatic misconnections observed in Clec2-/- mice resulting in severe edema formation and intestinal inflammation. Analysis of lymphatic and vascular development in embryonic mesenteries revealed severely defective blood-lymph-vessel separation, which translated into thrombocytopenia and increased vascular permeability due to reduced tight junction density in mesenteric blood vessels and consequent leakage of blood into the peritoneal cavity.
Recently, platelet granule release has been proposed to ameliorate the progression of retinopathy of prematurity (ROP), a fatal disease in newborns leading to retinal degradation. The mechanisms governing platelet activation in this process remained elusive nonetheless, which prompted us to investigate a possible role of ITAM signaling. In the second part of this thesis, granule release during ROP was shown to be GPVI- and partly CLEC-2-triggered since blockade or loss of these receptors markedly deteriorated ROP progression.
Proplatelet formation from MKs is highly dependent on a functional microtubule and actin cytoskeleton, the latter of which is regulated by several actin-monomer binding proteins including Cofilin1 and Twinfilin1 that have been associated with actin-severing at pointed ends. In the present study, a redundancy between both proteins especially important for the guided release of proplatelets into the bloodstream was identified, since deficiency in both proteins markedly impaired MK functionality mainly due to altered actin-microtubule crosstalk.
Besides ITAM-triggered activation, platelets and MKs are dependent on inhibitory receptors, which prevent overshooting activation. We here identified macrothrombocytopenic mice with a mutation within Mpig6b encoding the ITIM-bearing receptor G6b-B. G6b-B-mutant mice developed a severe myelofibrosis associated with sex-specific bone remodeling defects resulting in osteosclerosis and -porosis in female mice. Moreover, G6b-B was shown to be indispensable for MK maturation as verified by a significant reduction in MK-specific gene expression in G6b-B-mutant MKs due to reduced GATA-1 activity.
Arid environments cover almost one-third of the land over the world. Plant life in hot arid regions is prone to the water shortage and associated high temperatures. Drought-stressed plants close the stomata to reduce water loss. Under such conditions, the remaining water loss exclusively happens across the plant cuticle. The cuticular water permeability equals the minimum and inevitable water loss from the epidermal cells to the atmosphere under maximally stomatal closure. Thus, low cuticular water permeability is primordial for plant survival and viability under limited water source. The assumption that non-succulent xerophytes retard water loss due to the secretion of a heavier cuticle is often found in the literature. Intuitively, this seems to be plausible, but few studies have been conducted to evaluate the cuticular permeability of xerophilous plants. In chapter one, we investigated whether the cuticular permeability of Quercus coccifera L. grown in the aridest Mediterranean-subtype climate is indeed lower than that of individuals grown under temperate climate conditions. Also, the cuticular wax chemical compositions of plants grown in both habitats were qualitatively and quantitatively analysed by gas-chromatography. In few words, our findings showed that although the cuticular wax deposition increased in plants under Mediterranean climate, the cuticular permeability remained unaltered, regardless of habitat.
The associated high temperatures in arid regions can drastically increase the cuticular water permeability. Thereby, the thermal stability of the cuticular transpirational barrier is decisive for safeguarding non-succulent xerophytes against desiccation. The successful adaptation of plants to hot deserts might be based on finding different solutions to cope with water and heat stresses. Water-saver plants close the stomata before the leaf water potential drastically changes in order to prevent damage, whereas water-spender plants reduce the leaf water potential by opening the stomata, which allow them to extract water from the deep soil to compensate the high water loss by stomatal transpiration. In chapter two, we compare the thermal stability of the cuticular transpiration barrier of the desert water-saver Phoenix dactylifera L. and the water-spender Citrullus colocynthis (L.) Schrad. In short, the temperature-dependent increase of the cuticular permeability of P. dactylifera was linear over the whole temperature range (25-50°C), while that of C. colocynthis was biphasic with a steep increase at temperatures ≥ 40°C. This drastic increase of cuticular permeability indicates a thermally induced breakdown of the C. colocynthis cuticular transpiration barrier, which does not occur in P. dactylifera. We further discussed how the specific chemical composition of the cutin and cuticular waxes might contribute to the pronounced thermal resistance of the P. dactylifera cuticular transpiration barrier.
A multitude of morpho and physiological modifications, including photosynthetic thermal tolerance and traits related to water balance, led to the successful plant colonisation of hot arid regions over the globe. High evaporative demand and elevated temperatures very often go along together, thereby constraining the plant life in arid environments. In chapter 3, we surveyed cuticular permeability, leaf thermal tolerance, and cuticular wax chemical composition of 14 non-succulent plant species native from some of the hottest and driest biomes in South-America, Europe, and Asia. Our findings showed that xerophilous flowering plants present high variability for cuticular permeability and leaf thermal tolerance, but both physiological features could not be associated with the species original habitat. We also provide substantial evidence that non-succulent xerophytes with more efficient cuticular transpirational barrier have higher leaf thermal tolerance, which might indicate a potential coevolution of these features in hot arid biomes. We further discussed the efficiency of the cuticular transpiration barrier in function to the cuticular wax chemical composition in the general discussion section.
Evolution of antifungal drug resistance of the human-pathogenic fungus \(Candida\) \(albicans\)
(2021)
Infections with the opportunistic yeast Candida albicans are frequently treated with the first-line drug fluconazole, which inhibits ergosterol biosynthesis. An alarming problem in clinics is the development of resistances against this azole, especially during long-term treatment of patients. Well-known resistance mechanisms include mutations in the zinc cluster transcription factors (ZnTFs) Mrr1 and Tac1, which cause an overexpression of efflux pump genes, and Upc2, which results in an overexpression of the drug target. C. albicans strains with such gain-of-function mutations (GOF) have an increased drug resistance conferring a selective advantage in the presence of the drug. It was previously shown that this advantage comes with a fitness defect in the absence of the drug. This was observed in different conditions and is presumably caused by a deregulated gene expression.
One aim of the present study was to examine whether C. albicans can overcome the costs of drug resistance by further evolution. Therefore, the relative fitness of clinical isolates with one or a combination of different resistance mutations in Mrr1, Tac1 and/or Upc2 was analyzed in competition with the matched fluconazole-susceptible partner. Most fluconazole-resistant isolates had a decreased fitness in competition with their susceptible partner in vitro in rich medium. In contrast, three fluconazole-resistant strains with Mrr1 resistance mutations did not show a fitness defect in competition with their susceptible partner. In addition, the fitness of four selected clinical isolate pairs was examined in vivo in mouse models of gastrointestinal colonization (GI) and disseminated infection (IV). In the GI model all four fluconazole-resistant strains were outcompeted by their respective susceptible partner. In contrast, in the IV model only one out of four fluconazole-resistant isolates did show a slight fitness defect in competition with its susceptible partner during infection of the kidneys. It can be stated, that in the present work the in vitro fitness did not reflect the in vivo fitness and that the overall fitness was dependent on the tested conditions. In conclusion, C. albicans cannot easily overcome the costs of drug resistance caused by a deregulated gene expression.
In addition to GOFs in Mrr1, Tac1 and Upc2, resistance mutations in the drug target Erg11 are a further key fluconazole resistance mechanism of C. albicans. Clinical isolates often harbor several resistance mechanisms, as the fluconazole resistance level is further increased in strains with a combination of different resistance mutations. In this regard, the question arises of how strains with multiple resistance mechanisms evolve. One possibility is that strains acquire mutations successively. In the present study it was examined whether highly drug-resistant C. albicans strains with multiple resistance mechanisms can evolve by parasexual recombination as another possibility. In a clonal population, cells with individually acquired resistance mutations could combine these advantageous traits by mating. Thereupon selection could act on the mating progeny resulting in even better adapted derivatives.
Therefore, strains heterozygous for a resistance mutation and the mating type locus (MTL) were grown in the presence of fluconazole. Derivatives were isolated, which had become homozygous for the resistance mutation and at the same time for the MTL. This loss of heterozygosity was accompanied by increased drug resistance. In general, strains which are homozygous for one of both MTL configurations (MTLa and MTLα) can switch to the opaque phenotype, which is the mating-competent form of the yeast, and mate with cells of the opposite MTL. In the following, MTLa and MTLα homozygous strains in the opaque phenotype were mated in all possible combinations. The resulting mating products with combined genetic material from both parents did not show an increased drug resistance. Selected products of each mating cross were passaged with stepwise increasing concentrations of fluconazole. The isolated progeny showed high levels of drug resistance and loss of wild-type alleles of resistance-associated genes. In conclusion, selective pressure caused by fluconazole exposure selects for resistance mutations and at the same time induces genomic rearrangements, resulting in mating competence. Therefore, in a clonal population, cells with individually acquired resistance mutations can mate with each other and generate mating products with combined genetic backgrounds. Selection can act on these mating products and highly drug-resistant und thus highly adapted derivatives can evolve as a result.
In summary, the present study contributes to the current understanding of the evolution of antifungal drug resistance by elucidating the effect of resistance mutations on the fitness of the strains in the absence of the drug selection pressure and investigates how highly drug-resistant strains could evolve within a mammalian host.
Within this work, an additive and a subtractive QM/MM interface were implemented into CAST. The interactions between QM and MM system are described via electrostatic embedding. Link atoms are used to saturate dangling bonds originating from the separation of QM and MM system. Available energy evaluation methods to be combined include force fields (OPLSAA and AMBER), semi-empirical programs (Mopac and DFTB+), and quantum-chemical methods (from Gaussian, Orca, and Psi4). Both the additive and the subtractive interface can deal with periodic boundary conditions. The subtractive scheme was extended to enable QM/QM, three-layer, and multi-center calculations. Another feature only available within the subtractive interface is the microiteration procedure for local optimizations.
The novel QM/MM methods were applied to the investigation of the reaction path for the complex formation between rhodesain and K11777. Benchmark calculations show a very good agreement with results from Gaussian-ONIOM. When comparing the relative energies obtained with different options to a computation where the whole system was treated with the “QM method” DFTB3, the electrostatic embedding scheme with option “delM3” gives the best results. “delM3” means that atoms with up to three bonds distance to the QM region are ignored when creating the external charges. This is done in order to avoid a double counting of Coulomb interactions between QM and MM system. The embedding scheme for the inner system in a three-layer calculation, however, does not have a significant influence on the energies. The same is true for the choice of the coupling scheme: Whether the additive or the subtractive QM/MM interface is applied does not alter the results significantly. The choice of the QM region, though, proved to be an important factor. As can be seen from the comparison of two QM systems of different size, bigger is not always better here. Instead, one has to make sure not to separate important (polar) interactions by the QM/MM border.
After this benchmark study with singlepoint calculations, the various possibilities of CAST were used to approximate the solution of a remaining problem: The predicted reaction energy for the formation of the rhodesain-K11777 complex differs significantly depending on the starting point of the reaction path.
The reason for this is assumed to be an inadequate adjustment of the environment during the scans, which leads to a better stabilization of the starting structure in comparison to the final structure. The first approach to improve this adjustment was performing the relaxed scan with a bigger QM region instead of the minimal QM system used before. While the paths starting from the covalent complex do not change significantly, those starting from the non-covalent complex become more exothermic, leading to a higher similarity of the two paths. Nevertheless, the difference of the reaction energy is still around 15 kcal/mol, which is far from a perfect agreement. For this reason, Umbrella Samplings were run. Here, the adjustment of the environment is not done by local optimizations like in the scans, but by MD simulations. This has the advantage that the system can cross barriers and reach different local minima. The relative free energies obtained by Umbrella Samplings with suitable QM regions are nearly identical, independently of the starting point of the calculation. Thus, \(\Delta A\) evaluated by these computations can be assumed to reproduce the real energy change best. An MD simulation that was started from the transition state in order to mimic a “real-time” reaction indicates a very fast adjustment of the environment during the formation of the complex. This confirms that Umbrella Sampling is probably better suitable to describe the reaction path than a scan, where the environment can never move strong enough to leave the current local minimum.
Squaraine dyes have attracted more attention in the past decade due to their strong and narrow absorption and fluorescence along with the easily functionalized molecular structure. One successful approach of core functionalization is to replace one oxygen of the squaric carbonyl group with a dicyanomethylene group, which shifts the absorption and emission into the near infrared (NIR) region and at the same time leads to a rigid, planar structure with C2v symmetry. However, such squaraines tend to aggregate cofacially in solution due to dispersion forces and dipole-dipole interactions, usually leading to H-type exciton coupling with undesired blue-shifted spectrum and quenched fluorescence. Therefore, the goal of my research was the design of dicyanomethylene-substituted squaraine dyes that self-assemble into extended aggregates in solution with J-type coupling, in order to retain or even enhance their outstanding optical properties. Toward this goal, bis(squaraine) dyes were envisioned with two squaraine units covalently linked to trigger a slip-stacked packing motif within the aggregates to enable J-type coupling.
In my first project, bis(squaraine) dye BisSQ1 was synthesized, in which two dicyanomethylene squaraine chromophores are covalently linked. Concentration and temperature-dependent UV/Vis/NIR spectroscopy experiments reveal that BisSQ1 undergoes cooperative self-assembly resulting in J-type aggregates in a solvent mixture of toluene/1,1,2,2-tetrachloroethane (TCE) (98:2, v/v). The J type exciton coupling is evident from the significantly red shifted absorption maximum at 886 nm and the fluorescence peak at 904 nm. In conclusion, this was a first example to direct squaraine dye aggregation in solution to the more desired slip-stacked packing leading to J-type exciton coupling by simply connecting two dyes in a head-to-tail bis chromophore structure.
Connecting two squaraine dyes with an additional phenylene spacer (BisSQ2) leads to two different polymorphs with very distinct absorption spectra upon cooling down a solution of BisSQ2 in a solvent mixture of toluene/TCE (98:2, v/v) with different rates. Accordingly, rapid cooling resulted in rigid helical nanorods with an absorption spectrum showing a panchromatic feature, while slow cooling led to a sheet-like structure with a significant bathochromic shift in the absorption spectrum.
It was discovered that the conventional molecular exciton model failed to explain the panchromatic absorption features of the nanorods for the given packing arrangement, therefore more profound theoretical investigations based on the Essential States Model (ESM) were applied to unveil the importance of intermolecular charge transfer (ICT) to adequately describe the panchromatic absorption spectrum. Moreover, the red-shift observed in the spectrum for the sheet-like structure can be assigned to the interplay of Coulomb coupling and ICT-mediated coupling.
Furthermore, the same bis-chromophore strategy was adopted for constructing an NIR-II emitter with a bathochromically-shifted spectrum. In chloroform, BisSQ3 exhibits an absorption maximum at 961 nm with a significant bathochromic shift (1020 cm−1) compared to the reference mono-squaraine SQ, indicating intramolecular J-type coupling via head-to-tail arrangement of two squaraine dyes. Moreover, BisSQ3 shows a fluorescence peak at 971 nm with a decent quantum yield of 0.33%. In less polar toluene, BisSQ3 self-assembles into nanofibers with additional intermolecular J-type coupling, causing a pronounced bathochromic shift with absorption maximum at 1095 nm and a fluorescence peak at 1116 nm. Thus, connecting two quinoline-based squaraines in a head-to-tail fashion leads to not only intra-, but also intermolecular J-type exciton coupling, which serves as a promising strategy to shift the absorption and emission of organic fluorophores into the NIR-II window while retaining decent quantum yields.
In conclusion, my research illustrates based on squaraine dyes how a simple modification of the molecular structure can significantly affect the aggregation behavior and further alter the optical properties of dye aggregates. Elongated supramolecular structures based on dicyanomethylene substituted squaraine dyes were successfully established by covalently linking two squaraine units to form a bis-chromophore structure. Then, a simple but efficient general approach was established to direct squaraine dye aggregation in solution to the more desired slip-stacked packing leading to J-type exciton coupling by directly connecting two squaraine dyes in a head-to-tail fashion without spacer units. Moreover, the additional spacer between the squaraine dyes in BisSQ2 allowed different molecular conformations, which leads to two different morphologies depending on the cooling rates for a hot solution. Hence, this is a promising strategy to realize supramolecular polymorphism.
In general, it is expected that the concept of constructing J-aggregates by the bis-chromophore approach can be extended to entirely different classes of dyes since J-aggregates possess a variety of features such as spectral shifts into the NIR window, fluorescence enhancement, and light harvesting, which are commonly observed and utilized for numerous fundamental studies and applications. Moreover, the insights on short-range charge transfer coupling for squaraine dyes is considered of relevance for all materials based on alternating donor-acceptor π-systems. The panchromatic spectral feature is in particular crucial for acceptor-donor-acceptor (ADA) dyes, which are currently considered as very promising materials for the development of bulk heterojunction solar cells.
For the quality assurance of substances for pharmaceutical use, a variety of analytical techniques are available to address specific analytical problems. In this field of application, liquid chromatography (LC) stands out as the gold standard in the pharmaceutical industry. Various detectors can be employed, which are e.g. based on UV/Vis spectroscopy for the examination of molecules with a chromophore, or mass spectrometry (MS) for structural elucidation of analytes. For the separation of enantiomers, the use of capillary electrophoresis (CE) may be more favorable due to the high separation efficiency and easy-to-use and comparatively inexpensive chiral selectors, in contrast to chiral columns for LC, which are usually very expensive and limited to a restricted number of analytes. For structure elucidation in impurity profiling, one- and multidimensional 1H NMR spectroscopy is a valuable tool as long as the analyte molecule has got nuclei that can be detected, which applies for the magnitude of organic pharmaceutical substances.
For the evaluation of the amount of mineral oil aromatic hydrocarbons (MOAH) in various paraffin samples from different suppliers, a straightforward method based on 1H NMR spectroscopy was elaborated. The MOAH/MOSH ratio was used to indicate the amount of MOAH of paraffins and to evaluate the extent of refining. In addition, a representative paraffin sample was measured without sample solvent at high temperatures (about 340 K) to avoid the interfering residual solvent signals in the spectral regions of interest. The results of both methods were in good accordance.
Moreover, the 1H NMR results were complemented with the UV measurements from the purity testing of paraffins according to the DAB 8. Correlations of the NMR and UV spectroscopic data indicated a linear relationship of both methods for the determination of MOAH in paraffins.
Finally, the 1H NMR data was evaluated by principal component analysis (PCA) to explore differences within the paraffin samples and the spectral regions in the 1H NMR spectrum which are responsible for the formation of groups. It could be found that most variation is due to the MOSH of the paraffins. The PCA model was capable of differentiating between soft, liquid and solid paraffins on the one hand and between natural and synthetic liquid paraffins on the other hand.
The impurity profiling of L-ascorbic acid 2-phosphate magnesium (A2PMg) was performed by means of one- and two-dimensional NMR spectroscopy. Several ethylated impurities could be detected, which were likely to be formed during synthesis of A2PMg. The structures of two of the ethylated impurities were identified as ascorbic acid 2-phosphate ethyl ester and ethanol, (residual solvent from synthesis). NMR spectroscopic studies of the fractions obtained from preparative HPLC of A2PMg revealed two additional impurities, which were identified as phosphorylated derivatives of ascorbic acid, ascorbic acid 3,5-phosphate and ascorbic acid 5-phosphate.
Solid state mechanochemistry as an alternative approach for stress testing was applied on the drug substances S-Ibuprofen (Ibu) and Clopidogrel (CLP) using a ball mill, in order to study their degradation profile:
First, the isomerization of S-Ibu was investigated, which was stressed in the solid state applying several milling frequencies and durations under basic, acidic and neutral conditions. For the separation of Ibu enantiomers, a chiral CE method was developed and validated according to ICH Q2(R1). It was found that S-Ibu is overall very stable to isomerization; it shows minor conversion into the R-enantiomer under basic environment applying long milling times and high frequencies.
Last, the degradation profile of clopidogrel hydrogen sulfate (CLP) was investigated, which was stressed in the solid state under various oxidative conditions. An already existing HPLC-UV method was adjusted to sufficiently separate the degradation products, which were characterized by means of UV and MS/(MS) detection. Most of the degradation products identified were already reported to result from conventional CLP stress tests. The degradation profile of CLP was mainly influenced by the material of the milling jar and the type of catalyst used.
The charged aerosol detector (CAD) is an aerosol-based detector employed in liquid chromatography which has become established in the field of pharmaceutical analysis due to its outstanding performance characteristics, e.g. the almost uniform response for nonvolatile analytes. Owing to its principle of detection, the response of the CAD depends on the volatility of a compound and is inherently nonlinear. However, the newly implemented instrumental settings evaporation temperature and power function value (PFV) are valuable tools to overcome some of these drawbacks and can even enhance the detector’s capabilities when adjusted properly.
This thesis aimed to evaluate the impact of the new instrumental settings on the CAD performance. Additionally, the influence of modern separation techniques for small polar compounds on the CAD was assessed and the applicability of hyphenated UV-CAD techniques explored. The optimization strategies derived from the evaluation procedures and the conjunction of the instrumental and chromatographic techniques investigated were utilized for the challenging impurity profiling of amino acids and amino acid-like drugs.
The results of the method validation procedures confirmed the broad applicability of the CAD in the pharmaceutical analysis of nonvolatile compounds, supported by satisfactory sensitivity and reproducibility for meeting the regulatory requirements with respect to the ICH guidelines Q2(R1) and Q3A(R2). The limits of applicability include the analysis of semivolatile compounds, and the method transfer between current and legacy CAD models. Further advances in the definition and standardization of allowed ranges for the instrumental settings and the establishment of general optimization procedures in the method development could lead to a more widespread use of the detection technique in compendial methods.
Background: In recent years, health care has increasingly become the focus of public interest, politics, health insurance companies, and research. This includes the development of therapeutic concepts that can respond individually to patients' resources in order to improve coping with chronic diseases. Research into psychosocial and biological resilience factors is very important and the basic objective of the present work. I studied patients with fibromyalgia syndrome (FMS), who suffer among others from chronic pain, fatigue, sleep and gastrointestinal problems. This patient cohort is characterized by a pronounced heterogeneity in terms of clinical outcome, degree in disability and coping. FMS has a prevalence of 3 – 8 % in the Western population and has a significant socio-economic impact. Validated psychosocial resilience factors include optimism, humor, coherence, self-efficacy, awareness with one's own resources and the ability to apply them profitably (coping), and a healthy social environment with positive relationships. Studies in patients with cancer revealed religiosity as positive and negative factor on the health outcome, but there is little data on religious aspects of pain resilience. Various genetic polymorphisms and anti-inflammatory cytokines are known as biological resilience factors. Various microRNA (miRNA) were detected to contribute to resilience in the context of stress and psychiatric disorders. Objective: The underlying research question of this work is to understand the factors that make some FMS patients resilient and others not, even though they suffer from the same disease. The long-term aim was to understand mechanisms and influencing factors of resilience to design preventive and resource-oriented therapies for FMS patients. Material and Methods: Three studies examined religious, physiological, biological, and psychosocial factors which may contribute to resilience in FMS patients. Study one combined data of questionnaires, a psychosocial interview, and regression analyses to investigate the relevance of religiosity for coping and resilience. Study two examined variance explaining factors and defined clusters among FMS patients by their differences in coping, pain phenotype and disability. The factor analysis used variables derived from questionnaires and qPCR of cytokines in white blood samples (WBC) of patients and healthy controls. Study three assessed cluster-wise miRNA signatures which may underly differences in behaviour, emotional and physiological disability, and resilience among patient clusters. A cluster-specific speculative model of a miRNA-mediated regulatory cycle was proposed and its potential targets verified by an online tool. Results: The data from the first study revealed a not very religious patient cohort, which was rather ambivalent towards the institution church, but described itself as a believer. The degree of religiosity played a role in the choice of coping strategy but had no effect on psychological parameters or health outcomes. The coping strategy "reinterpretation", which is closely related iv to the religious coping "reappraisal", had the highest influence on FMS related disability. Cognitive active coping strategies such as reappraisal which belongs to religious coping had the highest effect on FMS related disability (resilience) and could be trained by a therapist. Results from the second study showed high variances of all measured cytokines within the patient group and no difference between patient and control group. The high dispersion indicated cluster among patients. Factor analysis extracted four variance-explaining factors named as affective load, coping, pain, and pro-inflammatory cytokines. Psychological factors such as depression were the most decisive factors of everyday stress in life and represented the greatest influence on the variance of the data. Study two identified four clusters with respective differences in the factors and characterized them as poorly adapted (maladaptive), well adapted (adaptive), vulnerable and resilient. Their naming was based on characteristics of both resilience concepts, indicated by patients who were less stress-sensitive and impaired as a personal characteristic and by patients who emerged as more resilient from a learning and adaptive process. The data from the variance analysis suggests that problem- and emotion-focused coping strategies and a more anti-inflammatory cytokine pattern are associated with low impairment and contribute to resilience. Additional favorable factors include low anxiety, acceptance, and persistence. Some cluster-specific intervention proposals were created that combine existing concepts of behavioral and mindfulness therapies with alternative therapies such as vitamin D supplementation and a healthy intestinal flora. The results of the third study revealed lower relative gene expression of miR103a-3p, miR107, and miR130a-3p in the FMS cohort compared to the healthy controls with a large effect size. The adaptive cluster had the highest gene expression of miR103a-3p and tendentially of miR107, which was correlated with the subscale score "physical abuse" of the trauma questionnaire. Further correlations were found in particular with pain catastrophizing and FMS-related disability. MiR103a-3p and miR107 form a miRNA-family. Based on this, we proposed a miR103a/107 regulated model of an adaptive process to stress, inflammation and pain by targeting genetic factors which are included in different anti-inflammatory and stress-regulating pathways. Conclusion: All three studies provide new insights into resilience in FMS patients. Cognitive coping (reappraisal/reinterpretation) plays a central role and thus offers therapeutic targets (reframing in the context of behavioral therapy). Religosity as a resilience factor was only partially valid for our patient cohort. Basically, the use of resource-oriented therapy in large institutions still requires research and interdisciplinary cooperation to create a consensus between the humanities, natural sciences and humanism.
Miniaturized satellites on a nanosatellite scale below 10kg of total mass contribute most to the number of launched satellites into Low Earth Orbit today. This results from the potential to design, integrate and launch these space missions within months at very low costs. In the past decade, the reliability in the fields of system design, communication, and attitude control have matured to allow for competitive applications in Earth observation, communication services, and science missions. The capability of orbit control is an important next step in this development, enabling operators to adjust orbits according to current mission needs and small satellite formation flight, which promotes new measurements in various fields of space science. Moreover, this ability makes missions with altitudes above the ISS comply with planned regulations regarding collision avoidance maneuvering.
This dissertation presents the successful implementation of orbit control capabilities on the pico-satellite class for the first time. This pioneering achievement is demonstrated on the 1U CubeSat UWE–4. A focus is on the integration and operation of an electric propulsion system on miniaturized satellites. Besides limitations in size, mass, and power of a pico-satellite, the choice of a suitable electric propulsion system was driven by electromagnetic cleanliness and the use as a combined attitude and orbit control system. Moreover, the integration of the propulsion system leaves the valuable space at the outer faces of the CubeSat structure unoccupied for future use by payloads. The used NanoFEEP propulsion system consists of four thruster heads, two neutralizers and two Power Processing Units (PPUs).
The thrusters can be used continuously for 50 minutes per orbit after the liquefaction of the propellant by dedicated heaters. The power consumption of a PPU with one activated thruster, its heater and a neutralizer at emitter current levels of 30-60μA or thrust levels of 2.6-5.5μN, respectively, is in the range of 430-1050mW. Two thruster heads were activated within the scope of in-orbit experiments. The thrust direction was determined using a novel algorithm within 15.7° and 13.2° of the mounting direction. Despite limited controllability of the remaining thrusters, thrust vector pointing was achieved using the magnetic actuators of the Attitude and Orbit Control System.
In mid 2020, several orbit control maneuvers changed the altitude of UWE–4, a first for pico-satellites. During the orbit lowering scenario with a duration of ten days, a single thruster head was activated in 78 orbits for 5:40 minutes per orbit. This resulted in a reduction of the orbit altitude by about 98.3m and applied a Delta v of 5.4cm/s to UWE–4. The same thruster was activated in another experiment during 44 orbits within five days for an average duration of 7:00 minutes per orbit. The altitude of UWE–4 was increased by about 81.2m and a Delta v of 4.4cm/s was applied. Additionally, a collision avoidance maneuver was executed in July 2020, which increased the distance of closest approach to the object by more than 5000m.
Educational robotics is an innovative approach to teaching and learning a variety of different concepts and skills as well as motivating students in the field of Science, Technology, Engineering, and Mathematics (STEM) education. This especially applies to educational robotics competitions such as, for example, the FIRST LEGO League, the RoboCup Junior, or the World Robot Olympiad as out-of-school and goal-oriented approach to educational robotics. These competitions have gained greatly in popularity in recent years and thousands of students participate in these competitions worldwide each year. Moreover, the corresponding technology became more accessible for teachers and students to use it in their classrooms and has arguably a high potential to impact the nature of science education at all levels. One skill, which is said to be benefitting from educational robotics, is problem solving. This thesis understands problem solving skills as engineering design skills (in contrast to scientific inquiry). Problem solving skills count as important skills as demanded by industry leaders and policy makers in the context of 21st century skills, which are relevant for students to be well-prepared for their future working life in today’s world, shaped by an ongoing process of automation, globalization, and digitalization. The overall aim of this thesis is to try to answer the question if educational robotics competitions such as the World Robot Olympiad (WRO) have a positive impact on students’ learning in terms of their problem solving skills (as part of 21st century skills). In detail, this thesis focuses on a) if students can improve their problem solving skills through participation in educational robotics competitions, b) how this skill development is accomplished, and c) the teachers’ support of their students during their learning process in the competition. The corresponding empirical studies were conducted throughout the seasons of 2018 and 2019 of the WRO in Germany. The results show overall positive effects of the participation in the WRO on students’ learning of problem solving skills. They display an increase of students’ problem solving skills, which is not moderated by other variables such as the competition’s category or age group, the students’ gender or experience, or the success of the teams at the competition. Moreover, the results indicate that students develop their problem solving skills by using a systematic engineering design process and sophisticated problem solving strategies. Lastly, the teacher’s role in the educational robotics competitions as manager and guide (in terms of the constructionist learning theory) of the students’ learning process (especially regarding the affective level) is underlined by the results of this thesis. All in all, this thesis contributes to the research gap concerning the lack of systematic evaluation of educational robotics to promote students’ learning by providing more (methodologically) sophisticated research on this topic. Thereby, this thesis follows the call for more rigorous (quantitative) research by the educational robotics community, which is necessary to validate the impact of educational robotics.
The following study, The Integration of Female Refugees in Germany: Perspectives of Women and an Analysis of Federal and Selected State and City Integration Policies from 1998-2019, is focused on the qualitative analysis of integration policy in Germany regarding female refugees. The states of North Rhine-Westphalia, Bavaria, and Saxony-Anhalt have been selected for this dissertation as well as the cities of Cologne, Wuerzburg, and Magdeburg. Through an analysis and comparison of integration policies and programs on the federal and selected state and city levels the question will be answered how recognized female refugees are taken into account with the development and formulation of integration policy in Germany. The analysis is then complemented through interviews with recognized female refugees in each of the states and cities. Through analyzing the results of the interviews the question will be answered how the women view their situation and integration. Through a comparison of the findings from the policy analysis and the interviews it will then be able to decipher if integration policies and programs are truly reaching their target group, if they are effective, or what hurdles they may be producing. The goal of the study is to provide initial findings on the overall integration of recognized female refugees in Germany in connection to integration policies in order to discover potential deficits or ineffective programs and policies which can then be further researched in order to produce concrete policy suggestions.
Owing to climate change, natural forest disturbances and consecutive salvage logging are drastically increasing worldwide, consequently increasing the importance of understanding how these disturbances would affect biodiversity conservation and provision of ecosystem services.
In chapter II, I used long-term water monitoring data and mid-term data on α-diversity of twelve species groups to quantify the effects of natural disturbances (windthrow and bark beetle) and salvage logging on concentrations of nitrate and dissolved organic carbon (DOC) in streamwater and α-diversity. I found that natural disturbances led to a temporal increase of nitrate concentrations in streamwater, but these concentrations remained within the health limits recommended by the World Health Organization for drinking water. Salvage logging did not exert any additional impact on nitrate and DOC concentrations, and hence did not affect streamwater quality. Thus, neither natural forest disturbances in watersheds nor associated salvage logging have a harmful effect on the quality of the streamwater used for drinking water. Natural disturbances increased the α-diversity in eight out of twelve species groups. Salvage logging additionally increased the α-diversity of five species groups related to open habitats, but decreased the biodiversity of three deadwood-dependent species groups.
In chapter III, I investigated whether salvage logging following natural disturbances (wildfire and windthrow) altered the natural successional trajectories of bird communities. I compiled data on breeding bird assemblages from nine study areas in North America, Europe and Asia, over a period of 17 years and tested whether bird community dissimilarities changed over time for taxonomic, functional and phylogenetic diversity when rare, common and dominant species were weighted differently. I found that salvage logging led to significantly larger dissimilarities than expected by chance and that these dissimilarities persisted over time for rare, common and dominant species, evolutionary lineages, and for rare functional groups. Dissimilarities were highest for rare, followed by common and dominant species.
In chapter IV, I investigated how β-diversity of 13 taxonomic groups would differ in intact, undisturbed forests, disturbed, unlogged forests and salvage-logged forests 11 years after a windthrow and salvage logging. The study suggests that both windthrow and salvage logging drive changes in between-treatment β-diversity, whereas windthrow alone seems to drive changes in within-treatment β-diversity. Over a decade after the windthrow at the studied site, the effect of subsequent salvage logging on within-treatment β-diversity was no longer detectable but the effect on between-treatment β-diversity persisted, with more prominent changes in saproxylic groups and rare species than in non-saproxylic groups or common and dominant species.
Based on these results, I suggest that salvage logging needs to be carefully weighed against its long-lasting impact on communities of rare species. Also, setting aside patches of naturally disturbed areas is a valuable management alternative as these patches would enable post-disturbance succession of bird communities in unmanaged patches and would promote the conservation of deadwood-dependent species, without posing health risks to drinking water sources.
Neuroblastoma is the most abundant, solid, extracranial tumor in early childhood and the leading cause of cancer-related childhood deaths worldwide. Patients with high-risk neuroblastoma often show MYCN-amplification and elevated levels of Aurora-A. They have a low overall survival and despite multimodal therapy options a poor therapeutic prognosis. MYCN-amplified neuroblastoma cells depend on Aurora-A functionality. Aurora-A stabilizes MYCN and prevents it from proteasomal degradation by competing with the E3 ligase SCFFBXW7. Interaction between Aurora-A and MYCN can be observed only in S phase of the cell cycle and activation of Aurora-A can be induced by MYCN in vitro. These findings suggest the existence of a profound interconnection between Aurora-A and MYCN in S phase. Nevertheless, the details remain elusive and were investigated in this study.
Fractionation experiments show that Aurora-A is recruited to chromatin in S phase in a MYCN-dependent manner. Albeit being unphosphorylated on the activating T288 residue, Aurora-A kinase activity was still present in S phase and several putative, novel targets were identified by phosphoproteomic analysis. Particularly, eight phosphosites dependent on MYCN-activated Aurora-A were identified. Additionally, phosphorylation of serine 10 on histone 3 was verified as a target of this complex in S phase. ChIP-sequencing experiments reveal that Aurora-A regulates transcription elongation as well as histone H3.3 variant incorporation in S phase. 4sU-sequencing as well as immunoblotting demonstrated that Aurora-A activity impacts splicing. PLA measurements between the transcription and replication machinery revealed that Aurora-A prevents the formation of transcription-replication conflicts, which activate of kinase ATR.
Aurora-A inhibitors are already used to treat neuroblastoma but display dose-limiting toxicity. To further improve Aurora-A based therapies, we investigated whether low doses of Aurora-A inhibitor combined with ATR inhibitor could increase the efficacy of the treatment albeit reducing toxicity. The study shows that the combination of both drugs leads to a reduction in cell growth as well as an increase in apoptosis in MYCN-amplified neuroblastoma cells, which is not observable in MYCN non-amplified neuroblastoma cells. This new approach was also tested by a collaboration partner in vivo resulting in a decrease in tumor burden, an increase in overall survival and a cure of 25% of TH-MYCN mice. These findings indicate indeed a therapeutic window for targeting MYCN-amplified neuroblastoma.
Genome Wide Association Studies (GWAS) have revolutionized the way on
how genotype-phenotype relations are assessed. In the 20 years long history
of GWAS, multiple challenges from a biological, computational, and statistical
point of view have been faced. The implementation of this technique using
the model plant species Arabidopsis thaliana, has enabled the detection of many
association for multiple traits. Despite a lot of studies implementing GWAS
have discovered new candidate genes for multiple traits, different samples are
used across studies. In many cases, either globally diverse samples or samples
composed of accessions from a geographically restricted area are used. With
the aim of comparing GWAS outcomes between populations from different
geographic areas, this thesis describes the performance of GWAS in different
European samples of A. thaliana. Here, association mapping results for flowering
time were compared. Chapter 2 describes the analyses of random resampling
from this original sample. The aim was to establish reduced subsamples to
later carry out GWAS and compare the outcomes between these subsamples.
In Chapter 3, the European sample was split into eight equally-sized local
samples representing different geographic regions. Next, GWAS was carried
out and an attempt was made to clarify the differences in GWAS outcomes.
Chapter 4 contains the results of a collaboration with Prof. Dr. Wolfgang Dröge-
Laser, in which my mainly task was the analysis of RNAseq data from A.
thaliana plants infected by pathogenic fungi. Finally, Appendix A presents a very
short description of my participation in the GHP Project on Access to Care for
Cardiometabolic Diseases (HPACC) at the university of Heidelberg.
The substitution of selected CC units by their isoelectronic and isosteric BN units in π−conjugated organic compounds (BN/CC isosterism), especially polycyclic aromatic hydrocarbons (PAHs), has emerged as a viable strategy to produce novel organic–inorganic hybrid materials with structural similarities to their all-carbon congeners, but in many cases with intriguing properties and functions.
In the first two chapters the synthesis and properties of novel BNB-doped phenalenyls, dithienoazadiborepins and dithienooxadiborepins are presented. The optoelectronic properties of these new building blocks can be effectively tuned by variation of the incorporated Ar (Mes, Tip, FMes) and R groups (H, Me, i-Pr, t-Bu, Ph). Theoretical investigations, including NICS (Nucleus Independent Chemical Shift) scans and AICD (Anisotropy of the Induced Current Density) calculations, have been performed which provide insight into their aromatic or antiaromatic character, respectively.
The incorporation of BP units, on the other hand, which are valence isoelectronic with BN and CC, into unsaturated organic compounds, has been scarcely studied, though the potential of the resulting BCP hybrid materials for electronic applications has been recognized quite recently. Main chain conjugated polymers featuring BP fragments in the backbone are unknown so far. The first molecular model compounds for a BP analogue of the conjugated polymer poly(p-phenylene vinylene) (PPV) are presented in chapter 3. Theoretical investigations revealed that the Mes* group to fully planarizes the phosphorus center, increasing the B=P double bond character and enabling conjugation over the BP unit. Different synthetic approaches to the molecular model compounds have been investigated and a viable synthetic strategy was found.
The present work builds on a conjugated electrochromic polymer with a highly transmissive and colorless bright state and its application in electrochromic devices. The main body of this work focuses on the investigation of the influence of moisture on electrochromic devices and solutions to overcome possible degradation of these devices due to moisture ingress.
Firstly, a series of EDOT derivatives with a terminal double bond in the lateral sidechain to potentially achieve a highly transmissive and fully colorless bright state was investigated. All of the EDOT derivatives were electrochemically polymerized and characterized by means of (in-situ) spectroelectrochemistry. The results highlight the dramatic influence of the terminal double bond on the improved visible light transmittance and color neutrality in the bright state. After detailed evaluation and comparison, the best performing compound, which contains a hexenyl sidechain (PEDOT-EthC6), was scaled-up by changing the deposition technique from an electrochemical to a chemical in-situ polymerization process on a R2R-pilot line in an industrially relevant environment. The R2R-processed PEDOTEthC6 half-cells were characterized in detail and provide enhanced electrochromic properties in terms of visible light transmittance and color neutrality in the bright state as well as short response times, improved contrast ratio, coloration efficiency and cycling stability (10 000 cycles).[21]
In a second step, the novel PEDOT-EthC6 electrochromic polymer was combined with a Prussian Blue counter electrode and a solid polymer electrolyte to form an all-solid-sate ECDs based on complementary switching electrodes and PET-ITO as flexible substrates. The fabricated ECDs were optically and spectroelectrochemically characterized. Excellent functionality of the S2S-processed flexible ECDs was maintained throughout 10 000 switching cycles under laboratory conditions. The ECDs offer enhanced electrochromic properties in terms of visible light transmittance change and color neutrality in the bright state as well as contrast ratio, coloration efficiency, cycling stability and fast response times. Furthermore, the final device assembly was transferred from a S2S-process to a continuous R2R-lamination process.[238]
In a third step, the PEDOT-EthC6/PB-based ECDs were submitted to conscious environmental aging tests. The emphasis of the research presented in this work, was mainly put at the influence of moisture and possible failure mechanisms regarding the PEDOT-EthC6/PB based ECDs. An intense brown coloration of the electrodes was observed while cycling the ECDs in humid atmospheres (90% rH) as a major degradation phenomenon. The brown coloration and a thereby accompanied loss of conductivity of the PET-ITO substrates was related to significant degradation of the ITO layers, inserted as the conductive layers in the flexible ECDs. A dissolution of the ITO thin films and formation of metallic indium particles on the surface of the ITO layers was observed that harmed the cycling stability enormously. The conductive layers of the aged ECDs were investigated by XRD, UV-Vis, SEM and spectroelectrochemical measurements and validated the supposed irreversible reduction of the ITO layers.[279]
In the absence of reasonable alternatives to PET-ITO for flexible (R2R-processed) ECDs, it is also important to investigate measures to avoid the degradation of ECDs. This is primarily associated with the avoidance of appropriate electrode potentials necessary for ITO reduction in humid atmospheres. As an intrinsic action point, the electrode potentials were investigated via electrochemical measurements in a three-electrode setup of an all-solid-state ECD. Extensive knowledge on the electrode potentials allowed the voltage-induced degradation of the ITO in flexible ECDs to be avoided through the implementation of an unbalanced electrode configuration (charge density ratio of working and counter electrode). It was possible to narrow the overall operational voltage window to an extent in which irreversible ITO reduction no longer occurs. The unbalanced electrode configuration lead to an improved cycling stability without harming other characteristics such as response time and light transmittance change and allows ECD operation in the presence of humidity.[279]
The avoidance of the mentioned degradation phenomena is further associated with appropriate sealing methods and materials as well as appropriate electrode and device fabrication processes. Since a variety of sealing materials is commercially available, due to the commercial launch of organic photovoltaic (OPV) and light emitting diodes (OLEDs), the focus in the present work was put to water-free electrode fabrication. As an extrinsic action point, a novel preparation method of a nanoscale PEDOT-EthC6 dispersion based on organic solvents is presented here in a final step. The water-free processing method gives access to straightforward printing and coating processes on flexible PET-ITO substrates and thus represents a promising and simplified alternative to the established PEDOT:PSS. The resulting nano-PEDOT-EthC6 thin films exhibit enhanced color neutrality and transmissivity in the bright state and are comparable to the properties of the in-situ polymerized PEDOT-EthC6 thin films.[280]
One of the fascinating features of meiotic prophase I, is the highly conserved
vigorous movements of homologous chromosomes. These movements are
critical for the success of essential events as homologs alignment, synapsis and
recombination. Several organisms studied so far, including mammals, worms,
yeast and plants achieve these movements by anchoring the chromosome ends
to specialized sites in the nuclear envelope (NE). This attachment requires
telomere adaptor proteins which have to date been identified in fission yeast
and mice.
The mouse meiosis-specific telomere adaptor proteins TERB1, TERB2, and
MAJIN are involved in the attachment of ubiquitous shelterin telomere to the
LINC complex, in an analogous mechanism as those described in fission yeast.
Despite the essential role of meiosis-specific telomere adaptor proteins, the
precise mechanism of anchorage of telomeres to the nuclear envelope, as well
as their evolutionary history, are still not well understood. Therefore, the main
aim of this thesis is to investigate the organization of the mouse meiosis-specific
telomere adaptor complex TERB1-TERB2-MAJIN and its evolutionary history.
In the first part of this thesis high-resolution Structured Illumination Microscopy
(SIM), indirect immunofluorescence and Telo-FISH on mouse spermatocytes
were used to determine precisely how the telomere complex proteins are
localized with relation to the shelterin telomeric TRF1 protein and telomeric
DNA. During zygotene and pachytene stages staining patterns revealed
extensively overlapping of meiotic telomere complex proteins distributions in
which TERB2 organization is more heterogeneous than TERB1 and MAJIN at
the chromosome ends. Further, TRF1 localization was shown at the side of
lateral elements (LEs) ends with grasp-like distribution surrounding the TERB1
and MAJIN signals in zygotene and pachytene stages. Interestingly, telomeric
DNA was shown to be laterally distributed and partially overlapping with the
more central distribution displayed by meiotic telomere complex proteins of LEs
ends. The combination of these results allowed to describe an alternative model
of the telomere attachment to the NE during meiotic prophase I. The second part of this thesis, analyses mouse TERB1, TERB2, and MAJIN
evolutionary history. The lack of similarity between mouse and fission yeast
meiotic-specific telomere adaptor proteins has raised the question about the
origin of this specific complex through evolution. To identify mouse TERB1,
TERB2, and MAJIN putative orthologues, computational approaches and
phylogenetic analyses were performed. Besides, to test their potential function
during meiosis, expression studies were conducted. From these analyses, it was
revealed that mouse meiosis-specific telomere complex is ancient, as it
originated as early as eumetazoans pointing to a single origin. The absence of
any homologs in Nematoda and only a few candidates detected in Arthropoda
for meiosis-specific telomere complex, seemed, that these proteins have been
lost/replaced or highly diversified in these lineages. Remarkably, TERB1, TERB2,
and MAJIN protein domains involved in the formation of the complex as well as
those required for the interaction with the telomere shelterin protein and the
LINC complexes revealed high sequence similarity across all clades. Finally,
gene expression in the cnidarian Hydra Vulgaris provided evidence that the
TERB1-TERB2-MAJIN complex is selectively expressed in the germline
suggesting conservation of meiotic functions across metazoan evolution.
In summary, this thesis provides significant insights into the meiosis-specific
telomere complex mechanism to engage telomeres to the nuclear envelope and
the elucidation of its origin in metazoans.
π-Conjugated oligomers and polymers with tricoordinate boron centers incorporated into the main chain have attracted considerable attention as the interaction of the vacant p orbital on boron with an adjacent π system of the chain leads to conjugated materials with intriguing optical and electronic properties. This enables applicability in organic electronics and optoelectronics (OLEDs, OFETs, photovoltaics) or as sensory materials.
The potential of our B–C coupling protocol using metal-free catalytic Si/B exchange condensation is demonstrated by the synthesis of a series of π-conjugated monodisperse (het)aryl oligoboranes. Variation of the (het)aryl moieties allowed for tunability of the optoelectronic properties of the materials. Additionally, catalytic C–C cross-coupling strategies were applied to synthesize oligofuryl-based mono- and bisboranes, as well as polymers. These studies led to very robust and highly emissive compounds (f up to 97 %), which allow for tuning of their emission color from blue to orange. Furthermore, this work includes investigations of reaction routes to a kinetically stabilized tetraoxaporphyrinogen.
Being a key aspect of this work, a full investigation of the mechanism of the catalytic Si/B exchange was carried out. Additionally, this work presents the use of borenium cations to perform B–C coupling via intermolecular electrophilic borylation. Similar to the Si/B exchange, this route is capable of giving access to diaryl(bromo)boranes.
The present thesis deals with optimisation problems with sparsity terms, either in the constraints which lead to cardinality-constrained problems or in the objective function which in turn lead to sparse optimisation problems. One of the primary aims of this work is to extend the so-called sequential optimality conditions to these two classes of problems. In recent years sequential optimality conditions have become increasingly popular in the realm of standard nonlinear programming. In contrast to the more well-known Karush-Kuhn-Tucker condition, they are genuine optimality conditions in the sense that every local minimiser satisfies these conditions without any further assumption. Lately they have also been extended to mathematical programmes with complementarity constraints. At around the same time it was also shown that optimisation problems with sparsity terms can be reformulated into problems which possess similar structures to mathematical programmes with complementarity constraints. These recent developments have become the impetus of the present work. But rather than working with the aforementioned reformulations which involve an artifical variable we shall first directly look at the problems themselves and derive sequential optimality conditions which are independent of any artificial variable. Afterwards we shall derive the weakest constraint qualifications associated with these conditions which relate them to the Karush-Kuhn-Tucker-type conditions. Another equally important aim of this work is to then consider the practicability of the derived sequential optimality conditions. The previously mentioned reformulations open up the possibilities to adapt methods which have been proven successful to handle mathematical programmes with complementarity constraints. We will show that the safeguarded augmented Lagrangian method and some regularisation methods may generate a point satisfying the derived conditions.