@phdthesis{Yuan2015, author = {Yuan, Jiayin}, title = {Poly(Ionic Liquid)s}, school = {Universit{\"a}t Potsdam}, pages = {300}, year = {2015}, language = {en} } @phdthesis{Yang2019, author = {Yang, Haojin}, title = {Deep representation learning for multimedia data analysis}, school = {Universit{\"a}t Potsdam}, pages = {278}, year = {2019}, language = {en} } @phdthesis{Vogel2021, author = {Vogel, Heike}, title = {Genetics of obesity and type 2 diabetes}, address = {Potsdam}, school = {Universit{\"a}t Potsdam}, pages = {183}, year = {2021}, abstract = {By using mouse outcross populations in combination with bioinformatic approaches, it was possible to identify and characterize novel genes regulating body weight, fat mass and β-cell function, which all contribute to the pathogenesis of obesity and T2D. In detail, the presented studies identified 1. Ifi202b/IFI16 as adipogenic gene involved in adipocyte commitment, maintenance of white adipocyte identity, fat cell size and the inflammatory state of adipose tissue. 2. Pla2g4a/PLA2G4A as gene linked to increased body weight and fat mass with a higher expression in adipose tissue of obese mice and pigs as well as in obese human subjects. 3. Ifgga2/IRGM as novel regulator of lipophagy protecting from excess hepatic lipid accumulation. 4. Nidd/DBA as a diabetogenic locus containing Kti12, Osbpl9, Ttc39a and Calr4 with differential expression in pancreatic islets and/or genetic variants. 5. miR-31 to be higher expressed in adipose tissue of obese and diabetic mice and humans targeting PPARy and GLUT4 and thereby involved in adipogenesis and insulin signaling. 6. Gjb4 as novel gene triggering the development of T2D by reducing insulin secretion, inducing apoptosis and inhibiting proliferation. The performed studies confirmed the complexity and strong genetic heritability character of obesity and T2D. A high number of genetic variations, each with a small effect, are collectively influencing the degree and severity of the disease. The use of mouse outcross populations is a valid tool for disease gene identification; however, to facilitate and accelerate the process of gene identification the combination of mouse cross data with advanced sequencing resources and the publicly available data sets are essential. The main goal for future studies should be the translation of these novel molecular discoveries to useful treatment therapies. More recently, several classes of novel unimolecular combination therapeutics have emerged with superior efficacy than currently prescribed options and pose the potential to reverse obesity and T2D (Finan et al., 2015). The glucagon-like peptide-1 (GLP-1)- estrogen conjugate, which targets estrogen into cells expressing GLP-1 receptors, was shown to improve energy, glucose and lipid metabolism as well as to reduce food reward (Finan et al., 2012; Schwenk et al., 2014; Vogel et al., 2016). Another possibility is the development of miRNA-based therapeutics to prevent obesity and T2D, such as miRNA mimetics, anti-miRNA oligonucleotides and exosomes loaded with miRNAs (Ji and Guo, 2019; Gottmann et al., 2020). As already described, genome-wide association studies for polygenic obesity and T2D traits in humans have also led to the identification of numerous gene variants with modest effect, most of them having an unknown function (Yazdi et al., 2015). These discoveries resulted in novel animal models and have illuminated new biologic pathways. Therefore, the integration of mouse-human genetic approaches and the utilization of the synergistic effects have the potential to lead to the identification of more genes responsible for common Mendelian forms of obesity and T2D, as well as gene × gene and gene × environment interactions (Yazdi et al., 2015; Ingelsson and McCarthy, 2018). This combination may help to unravel the missing heritability of obesity and T2D, to identify novel drug targets and to design more efficient and personalized obesity prevention and management programs.}, language = {en} } @phdthesis{Thonicke2019, author = {Thonicke, Kirsten}, title = {The influence of disturbance, climate extremes and land-use change on vegetation dynamics}, school = {Universit{\"a}t Potsdam}, year = {2019}, language = {en} } @phdthesis{Stroncik2019, author = {Stroncik, Nicole A.}, title = {Volatiles as tracers for mantle processes and magma formation and evolution}, pages = {102}, year = {2019}, abstract = {The geochemical composition of oceanic basalts provides us with a window into the distribution of geochemical elements within the Earth's mantle in space and time. In conjunction with a throughout knowledge on how the different elements behave e.g. during melt formation and evolution or on their partition behaviour between e.g. minerals and melts this information has been transformed into various models on how oceanic crust is formed along plume influenced or normal mid-ocean ridge segments, how oceanic crust evolves in response to seawater, on subduction recycling of oceanic crust and so forth. The work presented in this habilitation was aimed at refining existing models, putting further constraints on some of the major open questions in this field of research while at the same time trying to increase our knowledge on the behaviour of noble gases as a tracer for melt formation and evolution processes. In the line of this work the author and her co-workers were able to answer one of the major questions concerning the formation of oceanic crust along plume-influenced ridges - in which physical state does the plume material enter the ridge? Based on submarine volcanic glass He, Ne and Ar data, the author and her co-workers have shown that the interaction of mantle plumes with mid-ocean ridges occurs in the physical form of melts. In addition, the author and her co-workers have also put further constraints on one of the major questions concerning the formation of oceanic crust along normal mid-ocean ridges - namely how is the mid-ocean ridge system effectively cooled to form the lower oceanic crust? Based on Ne and Ar data in combination with Cl/K ratios of basaltic glass from the Mid-Atlantic ridge and estimates of crystallisation pressures they have shown, that seawater penetration reaches lower crustal levels close to the Moho, indicating that hydrothermal circulation might be an effective cooling mechanism even for the deep parts of the oceanic crust. Considering subduction recycling, the heterogeneity of the Earth's mantle and mantle dynamic processes the key question is on which temporal and spatial scales is the Earth's mantle geochemically heterogeneous? In the line of this work the author along with her co-workers have shown based on Cl/K ratios in conjunction with the Sr, Nd, and Pb isotopes of the OIBs representing the type localities for the different mantle endmembers that the quantity of Cl recycled into the mantle via subduction is not uniform and that neither the HIMU nor the EM1 and EM2 mantle components can be considered as distinct mantle endmembers. In addition, we have shown, based on He, Ne and Ar isotope and trace-element data from the Foundation hotspot that the near ridge seamounts of the Foundation seamount chain formed by the Foundation hotspot erupt lavas with a trace-element signature clearly characteristic of oceanic gabbro which indicates the existence of recycled, virtually unchanged lower oceanic crust in the plume source. This is a clear sign of the inefficiency of the stirring mechanism existing at mantle depth. Similar features are seen in other near-axis hotspot magmas around the world. Based on He, Sr, Nd, Pb and O isotopes and trace elements in primitive mafic dykes from the Etendeka flood basalts, NW Namibia the author along with her co-workers have shown that deep, less degassed mantle material carried up by a mantle plume contributed significantly to the flood basalt magmatism. The Etendeka flood basalts are part of the South Atlantic LIP, which is associated with the breakup of Gondwana, the formation of the Paran{\´a}-Etendeka flood basalts and the Walvis Ridge - Tristan da Cunha hotspot track. Thus reinforcing the lately often-challenged concept of mantle plumes and the role of mantle plumes in the formation of large igneous provinces. Studying the behaviour of noble gases during melt formation and evolution the author along with her co-workers has shown that He can be considerable more susceptible to changes during melt formation and evolution resulting not only in a complete decoupling of He isotopes from e.g. Ne or Pb isotopes but also in a complete loss of the primary mantle isotope signal. They have also shown that this decoupling occurs mainly during the melt formation processes requiring He to be more compatible during mantle melting than Ne. In addition, the author along with her co workers were able to show that incorporation of atmospheric noble gases into igneous rocks is in general a two-step process: (1) magma contamination by assimilation of altered oceanic crust results in the entrainment of air-equilibrated seawater noble gases; (2) atmospheric noble gases are adsorbed onto grain surfaces during sample preparation. This implies, considering the ubiquitous presence of the contamination signal, that magma contamination by assimilation of a seawater-sourced component is an integral part of mid-ocean ridge basalt evolution.}, language = {en} } @phdthesis{Schwanghart2022, author = {Schwanghart, Wolfgang}, title = {Digital elevation model analysis in geomorphology and natural hazards research}, year = {2022}, language = {en} } @phdthesis{Schleicher2019, author = {Schleicher, Anja Maria}, title = {The significance of clay minerals in active fault zones}, school = {Universit{\"a}t Potsdam}, pages = {167}, year = {2019}, abstract = {Die vorliegende Habilitationsschrift umfasst Forschungsergebnisse aus Studien, die sich mit Fluid-Gesteins-Wechselwirkungen und Deformationsprozessen in aktiven St{\"o}rungszonen befassen, wobei der Einfluss der Tonminerale auf das geochemische und hydromechanische Verhalten dieser St{\"o}rungen im Vordergrund steht. Kernproben (core) und Bohrklein (cuttings) aus vier verschiedenen Bohrprojekten an der San Andreas St{\"o}rung (USA), der Nankai Trough Subduktionszone und der Japan Trench Subduktionszone (Japan), sowie der Alpine St{\"o}rung in Neuseeland wurden untersucht. Die von ICDP (International Continental Scientific Drilling Program) und IODP (International Ocean Discovery Program) unterst{\"u}tzten Projekte verfolgen alle das Ziel, das Verhalten von Erdbeben besser zu verstehen. In Kapitel 1 werden in einer kurzen Einleitung die allgemeinen thematischen Grundlagen und Ziele der Arbeit beschrieben. Kapitel 2 umfasst den Stand der Forschung, eine kurze Beschreibung der einzelnen Bohrprojekte und Standorte, sowie eine Zusammenfassung der wichtigsten Messmethoden. Kapitel 3 beinhaltet insgesamt zehn wissenschaftliche Arbeiten, die alle in einem methodisch-thematischen Zusammenhang stehen. Die Manuskripte wurden in den Jahren 2006-2015 ver{\"o}ffentlicht, wobei weitere Arbeiten aus diesem Themenbereich im Literaturverzeichnis vermerkt sind. Sie gehen auf unterschiedliche Fragestellungen um die Bildung und das Verhalten von Tonmineralen in aktiven St{\"o}rungszonen ein. Insgesamt sechs Publikationen beinhalten Daten und Forschungsergebnisse, die im Rahmen des SAFOD Projektes, USA (San Andreas Fault Observatory at Depth) erstellt wurden. Hier wurde vor allem auf die Fluid-Gesteins-Wechselwirkungsprozesse im St{\"o}rungsgestein und die daraus resultierende Bildung von Tonmineralen eingegangen. Drei weitere Arbeiten wurden im Rahmen des NanTroSEIZE Projektes, Japan (Nankai Trough Seismogenic Zone Experiment) und des JFAST Projektes, Japan (Japan Trench Fast Drilling Project) erstellt. Hier steht vor allem das Verhalten von quellf{\"a}higen Tonmineralen auf sich {\"a}ndernde Umgebungsbedingungen (z.B. Temperatur und Feuchtigkeit) im Mittelpunkt. Die zehnte hier vorgestellte Ver{\"o}ffentlichung betrifft Analysen rund um das DFDP Projekt (Deep Fault Drilling Project) in Neuseeland, wobei hier die Deformation von Tonmineralen und das hydro-mechanische Verhalten der St{\"o}rungszone im Vordergrund stehen. In neun Ver{\"o}ffentlichungen war ich als Erstautor f{\"u}r die Vorbereitung des Projektes, das Erstellen der Daten und die Fertigstellung der Manuskripte zust{\"a}ndig. In einer Publikation war ich als Mitautorin f{\"u}r die elektronenmikroskopischen Analysen und deren Interpretation verantwortlich. Die wichtigsten Ergebnisse der in Kapitel 3 vorgelegten Arbeiten werden in Kapitel 4 unter Ber{\"u}cksichtigung neuer Publikationen diskutiert. Nach der Beschreibung der Thesen in Kapitel 5 werden in Kapitel 6 „Outlook" die Highlights zuk{\"u}nftiger Forschungspl{\"a}ne am GFZ n{\"a}her beschrieben. Die Habilitationsschrift endet mit dem Anhang, in welchem unter anderem das Laborequipment genauer beschrieben wird, sowie die Publikationen, Konferenzbeitr{\"a}ge und Lehrbeitr{\"a}ge aufgelistet sind.}, language = {en} } @phdthesis{Scheffler2018, author = {Scheffler, Christiane}, title = {Studies on plasticity within the universal pattern of growth and developmet of children and adolescents}, school = {Universit{\"a}t Potsdam}, pages = {207}, year = {2018}, abstract = {The anatomically modern human Homo sapiens sapiens is distinguished by a high adaptability in physiology, physique and behaviour in short term changing environmental conditions. Since our environmental factors are constantly changing because of anthropogenic influences, the question arises as to how far we have an impact on the human phenotype in the very sensitive growth phase in children and adolescents. Growth and development of all children and adolescents follow a universal and typical pattern. This pattern has evolved as the result of trade-offs in the 6-7 million years of human evolution. This typically human growth pattern differs from that of other long-living social primate species. It can be divided into different biological age stages, with specific biological, cognitive and socio-cultural signs. Phenotypic plasticity is the ability of an organism to react to an internal or external environmental input with a change in the form, state, and movement rate of activity (West-Eberhard 2003). The plasticity becomes visible and measurable particularly when, in addition to the normal variability of the phenotypic characteristics within a population, the manifestation of this plasticity changes within a relatively short time. The focus of the present work is the comparison of age-specific dimensional changes. The basic of the presented studies are more than 75,000 anthropometric data-sets of children and adolescence from 1980 up today and historical data of height available in scientific literature. Due to reduced daily physical activity, today's 6-18 year-olds have lower values of pelvic and elbow breadths. The observed increase in body height can be explained by hierarchies in social networks of human societies, contrary to earlier explanations (influence of nutrition, good living conditions and genetics). A shift towards a more feminine fat distribution pattern in boys and girls is parallel to the increase in chemicals in our environment that can affect the hormone system. Changing environmental conditions can have selective effects over generations so that that genotype becomes increasingly prevalent whose individuals have a higher progeny rate than other individuals in this population. Those then form the phenotype which allows optimum adaptation to the changes of the environmental conditions. Due to the slow patterns of succession and the low progeny rate (Hawkes et al. 1998), fast visible in the phenotype due to changes in the genotype of a population are unlikely to occur in the case of Homo sapiens sapiens within short time. In the data sets on which the presented investigations are based, such changes appear virtually impossible. The study periods cover 5-30 to max.100 years (based on data from the body height from historical data sets).}, language = {en} } @phdthesis{Schaefer2021, author = {Schaefer, Laura}, title = {Oszillation und Adaptation als Mechanismen neuromuskul{\"a}rer Steuer- und Regelprozesse}, school = {Universit{\"a}t Potsdam}, year = {2021}, language = {de} } @phdthesis{Savatieiev2023, author = {Savatieiev, Oleksandr}, title = {Carbon nitride semiconductors: properties and application as photocatalysts in organic synthesis}, school = {Universit{\"a}t Potsdam}, pages = {272}, year = {2023}, abstract = {Graphitic carbon nitrides (g-CNs) are represented by melon-type g-CN, poly(heptazine imides) (PHIs), triazine-based g-CN and poly(triazine imide) with intercalated LiCl (PTI/Li+Cl‒). These materials are composed of sp2-hybridized carbon and nitrogen atoms; C:N ratio is close to 3:4; the building unit is 1,3,5-triazine or tri-s-triazine; the building units are interconnected covalently via sp2-hybridized nitrogen atoms or NH-moieties; the layers are assembled into a stack via weak van der Waals forces as in graphite. Due to medium band gap (~2.7 eV) g-CNs, such as melon-type g-CN and PHIs, are excited by photons with wavelength ≤ 460 nm. Since 2009 g-CNs have been actively studied as photocatalysts in evolution of hydrogen and oxygen - two half-reactions of full water splitting, by employing corresponding sacrificial agents. At the same time application of g-CNs as photocatalysts in organic synthesis has been remaining limited to few reactions only. Cumulative Habilitation summarizes research work conducted by the group 'Innovative Heterogeneous Photocatalysis' between 2017-2023 in the field of carbon nitride organic photocatalysis, which is led by Dr. Oleksandr Savatieiev. g-CN photocatalysts activate molecules, i.e. generate their more reactive open-shell intermediates, via three modes: i) Photoinduced electron transfer (PET); ii) Excited state proton-coupled electron transfer (ES-PCET) or direct hydrogen atom transfer (dHAT); iii) Energy transfer (EnT). The scope of reactions that proceed via oxidative PET, i.e. one-electron oxidation of a substrate to the corresponding radical cation, are represented by synthesis of sulfonylchlorides from S-acetylthiophenols. The scope of reactions that proceed via reductive PET, i.e. one-electron reduction of a substrate to the corresponding radical anion, are represented by synthesis of γ,γ-dichloroketones from the enones and chloroform. Due to abundance of sp2-hybridized nitrogen atoms in the structure of g-CN materials, they are able to cleave X-H bonds in organic molecules and store temporary hydrogen atom. ES-PCET or dHAT mode of organic molecules activation to the corresponding radicals is implemented for substrates featuring relatively acidic X-H bonds and those that are characterized by low bond dissociation energy, such as C-H bond next to the heteroelements. On the other hand, reductively quenched g-CN carrying hydrogen atom reduces a carbonyl compound to the ketyl radical via PCET that is thermodynamically more favorable pathway compared to the electron transfer. The scope of these reactions is represented by cyclodimerization of α,β-unsaturated ketones to cyclopentanoles. g-CN excited state demonstrates complex dynamics with the initial formation of singlet excited state, which upon intersystem crossing produces triplet excited state that is characterized by the lifetime > 2 μs. Due to long lifetime, g-CN activate organic molecules via EnT. For example, g-CN sensitizes singlet oxygen, which is the key intermediate in the dehydrogenation of aldoximes to nitrileoxides. The transient nitrileoxide undergoes [3+2]-cycloaddition to nitriles and gives oxadiazoles-1,2,4. PET, ES-PCET and EnT are fundamental phenomena that are applied beyond organic photocatalysis. Hybrid composite is formed by combining conductive polymers, such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) with potassium poly(heptazine imide) (K-PHI). Upon PET, K-PHI modulated population of polarons and therefore conductivity of PEDOT:PSS. The initial state of PEDOT:PSS is recovered upon material exposure to O2. K-PHI:PEDOT:PSS may be applied in O2 sensing. In the presence of electron donors, such as tertiary amines and alcohols, and irradiation with light, K-PHI undergoes photocharging - the g-CN material accumulates electrons and charge-compensating cations. Such photocharged state is stable under anaerobic conditions for weeks, but at the same time it is a strong reductant. This feature allows decoupling in time light harvesting and energy storage in the form of electron-proton couples from utilization in organic synthesis. The photocharged state of K-PHI reduces nitrobenzene to aniline, and enables dimerization of α,β-unsaturated ketones to hexadienones in dark.}, language = {en} }