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Dissertation
The tRNA binding protein Kti12 and its role in the regulation of Elongator complex
(2020-06-08)
[Summary] Kti12 is a conserved eukaryotic protein showing sequence homology to O-phosphoseryltRNA kinase (Pstk), which is required for the synthesis of selenocysteine tRNA. Saccharomyces cerevisiae Kti12 was originally discovered in a genetic screening for resistance against zymocin, a protein toxin produced by Kluyveromyces lactis. The cytotoxicity of zymocin lies in its anticodon nuclease activity, causing tRNA depletion and cell death in sensitive yeast cells. It recognizes and cleaves a particular wobble uridine ...
Dissertation
Investigation of the functional synergy and involvement of different tRNA modifications in translational control
(2020-07-02)
Transfer RNAs are essential adapter molecules employed in the translational process and are highly modified all over their structure. Specific modification of the four canonical ribonucleotides (A, U, C, G) is accomplished by various proteins and/or protein complexes, ranging from simple isomerisations (e.g. Ψ) and methylations (e.g. m5C) up to complex chemical structures (e.g. mcm5s2U, ct6A). The functions of tRNA modifications are linked to the specific position and may influence translation by supporting the native ...
Dissertation
High temperature-stable InGaAs QDs for the monolithic integration in external-cavity surface-emitting lasers
(2021)
Optically pumped vertical external-cavity surface-emitting lasers (VECSELs), also called semiconductor disk lasers (SDLs), benefit from the flexibility and versatility of the semiconductor material. With a simple cavity layout, fundamental transverse mode operation with a circular output beam and high beam quality is possible. They have excellent heat-sink properties and only require inexpensive multimode diode lasers for pumping. The complete VECSEL structure is only a few micrometers thick which leads to a strong ...
Dissertation
Integrierte hydrologische Modellierung von Oberflächen- und Grundwasser in dem mesoskaligen Einzugsgebiet des Rautenbach, Nordhessen
(2021-07)
In den vergangenen Jahren kam es in Europa vermehrt zu sommerlichen Dürreperioden mit erheblichen Beeinträchtigungen der Ökosysteme sowie für Land- und Forstwirtschaft. Die dadurch zunehmenden Herausforderungen an das Wasserressourcenmanagement fordern ein erweitertes Systemverständnis, welches durch realitätsnahe hydrologische Modellierung gewonnen werden kann.
Integrierte hydrologische Modelle ermöglichen die räumlich und zeitlich differenzierte Abbildung ober- und unterirdischer Abflüsse und derer Wechselwirkungen. ...
Dissertation
Fabrication and characterization of diamond nanopillars, waveguides and AFM tips with incorporated color centers
(2020-06)
Diamond is a unique material with outstanding properties and the perfect host for different crystal defects in its lattice, so-called color centers, which provide exceptional spin properties, rendering them a promising platform for the development of novel devices and components in quantum information technologies (QIT) and quantum sensing applications. To overcome diamond's high internal reflection due to its high refractive index, color centers need to be incorporated in photonic diamond structures, leading to ...
Dissertation
Technical and Environmental Assessment of Energy and Material Production from Rural and Urban Residual Biomass
(2020-04)
Die vorliegende Arbeit umfasst Studien zur Untersuchung technischer und ökologischer Aspekte bei der Nutzung von Restbiomassen in den Nutzungspfaden Energieerzeugung und Aktivkohleproduktion. Im Mittelpunkt der jeweiligen Untersuchung stand das Verfahren zur integrierten Erzeugung von Festbrennstoff und Biogas aus Biomasse (IFBB) und dessen Einfluss auf technische und ökologische Aspekte bei der Verwertung von Restbiomassen. Im Zuge von Naturschutz- und Landschaftspflegemaßnahmen auf extensiv bewirtschafteten ...
Dissertation
Synthese von Ester- und Etherlipiden durch die GPAT/AGPAT-Proteinfamilie und Lipin in Dictyostelium
(2021-05-12)
The synthesis of glycerolipids starts with the acylation of lipid backbones. Two structurally different glycerolipids emerge in the cell: ether-lipids and ester-lipids. In the case of ether-lipids the first fatty acid is substituted with a fatty alcohol inside the peroxisome. By the characterization of the protein FARAT in this thesis, a key enzyme in etherlipid-synthesis was identified for D. discoideum. FARAT shows a peroxisomal localization and is in principle able to do two jobs. Firstly, it initiates the peroxisomal ...
Dissertation
Ferrocen-basierte N-heterocyclische Tetrylene mit tertiären Alkylsubstituenten an den Stickstoff-Atomen
(2020)
In 2009, our group published two stable N-heterocyclic carbenes (NHCs) with a 1,1'-ferrocenediyl backbone (fc), which formally exhibit a six-membered FeIIC2N2CII-heterocycle. The stabilization of the fcNHCs is favored by bulky N-substituents. So far neopentyl and 2-adamantyl have been used for this purpose - a bulky primary and secondary alkyl substituent. In contrast to other cyclic diaminocarbenes, the fcNHCs are capable of activating small molecules such as NH3 or CO. The reason for this remarkable ability is the ...
Dissertation
Power Series Representations of Hypergeometric Type and Non-Holonomic Functions in Computer Algebra
(2020-06-10)
A Laurent-Puiseux series
$$ \sum\limits_{n = n_0}^{\infty }{a_n (z - z_0)^{n/k} (a_n \in K, k \in ℕ, n_0 \in ℤ ) } \quad (1) $$
where $ k $ denotes the corresponding Puiseux number and $ K $ an infinite computable field - mostly $ K= ℚ(α_1,\ldots,α_n) $ : a field of rational functions in several variables, is mainly characterized by the general coefficient. We consider the case where an is a term of an m-fold hypergeometric sequence.
That is $ a_{n+m} = r(n) a_n $ for all sufficiently large integers $ n, r(n) $ ...
Dissertation
Analysis of key pungent compounds in mustard products: A comparison of sensory and chemical–analytical determinations
(2020)
The consumption of mustard, horseradish and wasabi is characterized by a pungent sensation and lachrymatory effect primarily induced by allyl isothiocyanate (AITC). This study aimed to check the possible correlation between sensory-perceived pungency and the quality-determining pungency-inducing ingredients of mustard.
Primarily, the detection thresholds of sinigrin in a water-based matrix and AITC in water- and oil-based matrices were determined in a prestudy and a main study. In the prestudy, the resulting value ...