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Dissertation
Development of digital fluorescence light sheet microscopy for high-resolution optical imaging
(2021-12-15)
In modern biology investigating the morphological development of an organism is an inevitable task. Optical microscopy has been extensively used to monitor the live tissue changes in a model organism and it is typically used in conjunction with white light or fluorescence microscopy. The fluorescence microscopy occupies a significant place in biological research due to its ability to address various biological question at subcellular level of a biological sample. One of the more recent developments in fluorescence ...
Dissertation
Vergleichende phylogeographische und populationsgenetische Untersuchungen an der Pionierbaumgattung Macaranga (Euphorbiaceae) in Sundaland
(2022)
Die vorliegende Arbeit beschäftigt sich mit der Phylogeographie und Populationsgenetik der Pionierbaumgattung Macaranga in Sundaland, einer Region, die die Großen Sundainseln Sumatra, Borneo, Java und die malaiische Halbinsel umfasst. Eine Vielzahl der 300 in dieser Gattung enthaltenen Arten sind Wiederbesiedler gestörter Areale und sind daher in Sekundärwaldstrukturen besonders häufig. Im Rahmen dieser Dissertation wurden Studien in ganz Sundaland zu den sechs Arten M. tanarius (Tanarius-Artengruppe), M. gigantea, ...
Dissertation
Functional characterization of disease-associated mutations in type I cGMP-dependent protein kinase
(2022-08)
Cardiovascular diseases are the leading cause of death worldwide, and while mainly associated with behavioral risk factors, they can also be linked to genetic disorders. The cGMP-dependent protein kinase type I (PKG I) plays a pivotal role in the homeostasis of the vasculature by mediating NO/cGMP-dependent relaxation of vascular smooth muscle cells. A recently described genetic risk factor associated with PKG I results in heritable thoracic aortic aneurysms and dissections (TAAD). Although PKG isoforms Iα and Iβ ...
Dissertation
Synthese von [3]Ferrocenophanen und Ferrocen-verbrückten Oligophosphanen zur (elektro-)chemischen Erzeugung Phosphor-basierter Radikale
(2021-12)
Phosphor-basierte Radikale wurden in der Vergangenheit neben der bewährten Verwendung zur Phosphanierung von (an-)organischen Verbindungen auch als Reduktionsmittel in Einzelelektronen-Transfer-Reaktionen, als Radikalstarter oder als Flammschutzmittel eingesetzt. Ein geeigneter Weg, solche Radikale zu erzeugen, führt über eine thermisch induzierte homolytische Spaltung einer zentralen, sterisch abgeschirmten, elektronenreichen Bindung wie in Bisaminodiphosphanen X₂P PX₂ (X = NR₂). Ein Nachteil sind hier die meist ...
Dissertation
Mathematical Modelling and Adaptive Finite Element Simulation of Viscoelastic Fluid-Structure Interaction Systems and Chemical Processes with Applications to Ophthalmology
(2023)
The aim of this thesis is the numerical analysis of nonlinear coupled partial differential equations and their application to ophthalmology. Firstly, we consider fluid-structure interaction problems where the fluid is either Newtonian or viscoelastic. The structure is modelled as a hyperelastic material. The application to ophthalmology lies in the interaction of the vitreous with its surrounding elastic structures like the sclera and the lens. The underlying flow in the vitreous is modelled by a viscoelastic Burgers ...
Dissertation
Magnetic Textures and Magnetization Reversal Processes in Arrays of Ferromagnetic and Exchange-Biased Hollow Hemispheres
(2022)
The main objective of this thesis is to investigate hemispherical caps prepared by thin film deposition of magnetic material compositions on top of nano- and micrometer sized silica spheres. When compared to flat magnetic discs, these microcaps differ in their magnetic properties due to the curved and therefore three-dimensional shape. However, under certain conditions, both microstructures have previously been proven to express the famous magnetic vortex texture because of the confinement into a circular shape. ...
Dissertation
Electronic Theory of the Magnetic Order, Anisotropy and Reversal Processes in Rolled-Up Stripes and Thin Films
(2022)
A comprehensive multiscale approach consisting of a combination of state of the art, first principles quantum theory and the flexible statistical methodologies of complex systems is applied in order to achieve a detailed microscopic understanding of the magnetic properties of rolled-up transition-metal [TM] ultrathin films and stripes. A quantum electronic investigations of the effective interactions between the local magnetic moments is performed as a function of composition and rolling radius R including the limit ...
Dissertation
Investigations on Diamond Thin Films as Implant Coating and Biosensing Platform
(2021)
Diamond is researched in biological context for decades. Fundamental research has established diamond as a material that combines a pronounced compatibility with biological entities and resilience against even the harshest chemical and physical conditions. The present dissertation strives to improve the abilities of diamond in this matter even further by utilizing methods of nanostructuring and biochemical functionalization. Numerous characterization methods are used to monitor each step in detail and to evaluate the ...
Dissertation
Pollen Metabarcoding: Theory and Application
(2022-01)
Der vom Menschen verursachte Verlust der biologischen Vielfalt bedroht die Versorgungssicherheit durch Ökosystemleistungen, wie beispielsweise Bestäubung. Da unser Überleben als Spezies hiervon abhängt, ist es notwendig, unser Wissen über die Biodiversität in beschleunigter Weise zu erweitern, um dieser Bedrohung zu begegnen. Im Gegensatz zu dem Barcoding, bei welchem ein unbestimmter Organismus mit Hilfe eines Teils seiner DNS durch Abgleich mit einer Referenzdatenbank bestimmt wird, handelt es sich beim Metabarcoding ...
Dissertation
Optimal Control of Quantum Information Tasks in Open Quantum Systems
(2020-07-30)
Every quantum system inevitably interacts with its environment. This is a fundamental requirement that allows us to control, measure and, in general, interact with quantum systems. In that respect, a quantum system's openness can be interpreted as prerequisite that enables quantum technologies in the first place. The latter are built to harness the intrinsic quantum mechanical behavior of quantum devices in order to build new, powerful technologies. However, a quantum system's openness also causes it to interact ...