Health
The Amazon is the largest River on earth, accounting for 15–20% of the global river freshwater discharge, and making it an important source of trace metals, nutrients and organic matter to the Atlantic Ocean. The nearby Pará River is the 5th largest river and converges to mix in the Amazon Estuary. Trace metals in the ocean (e.g., Mn, Co, Fe, Ni, Cu, Zn, Cd and Pb) act as important nutrients and/or toxins to marine organisms. However, no data exists for these trace metals in the Amazon Estuary after 1976. Therefore, it is of urgent importance to establish a baseline for trace metals in the Amazon estuary. A GEOTRACES process study (cruise GApr11) was conducted in the Amazon estuary during the wet season (April–May) of 2018. Herein we present data for dissolved trace metals and organic matter from samples collected from this cruise. Chapter 1 focuses on copper (Cu), a micronutrient and potential toxin, and its complexation to organic ligands. Chapter 2 discusses two other micronutrients, cobalt (Co) and nickel (Ni), in surface and depth samples analyzed by two different methods. Chapter 3 brings together all trace metals from this study (Al, Mn, Co, Fe, Ni, Cu, Zn, Cd, Pb and U) to calculate the fluxes from the Amazon and Pará Rivers into the Atlantic Ocean. Finally, chapter 4 describes depth profiles of bioactive metals in different size fractions. Trace metal cycling in the estuary was influenced by complex biogeochemical processes, including ligand complexation, particle adsorption-desorption, colloidal flocculation, physical mixing and biological activity. In addition, we observed distinct influences from the Amazon and Pará Rivers, which draw from distinct catchment areas. Cu was mostly conservative with respect to salinity, while Fe and Pb were highly particle reactive during early mixing and experienced the greatest estuary removal. We estimated that the Amazon and Pará Rivers account for ~21% and 18% of the global riverine Cu and Ni to the oceans.
Synthesis, Structural Characterization and Catalytic Studies of Peroxo-Containing Heteropolyanions
(2023)
Polyoxometalates (POMs) are discrete, anionic metal-oxo clusters comprising early d-block metal ions in high oxidation states. Due to the large compositional and structural variety, POMs exhibit many interesting physicochemical properties including catalysis.POMs containing peroxo-groups are of special interest in hydrogen peroxide-assisted oxidation catalysis. In this thesis, the focus is on the synthesis of novel peroxo-containing POMs, the solid-state and solution characterization, and a study of their H2O2-based biphasic homogenous as well as heterogenous oxidation catalysis. Chapter 1 is an introduction of POMs and peroxo-POMs, whereas in Chapter 2 the motivation for the planned work is lined out. In Chapter 3, the experimental details are described, as well as the instruments used for the structural characterization and catalytic studies. In Chapter 4 some novel peroxo-Zr/Hf-containing Wells-Dawson anions are reported, which were studied for various H2O2-mediated oxidation reactions, using homogenous and supported conditions. A comparative study was also carried out on structurally-related peroxo-Zr/Hf Keggin anions. In Chapter 5 several novel peroxo-Ce-containing POMs of the Wells-Dawson type were isolated and structurally characterized in solution and in the solid state, followed by a comparative catalytic study using homogenous and supported conditions for the biphasic alcohol oxidation as well as alkene epoxidation. Chapter 6 describes the synthesis and characterization of a peroxo-Ce-containing POM of the Keggin type with the highest nuclearity amongst all peroxo-cerium POMs reported to date. Finally, Chapter 8 describes the synthesis and structural characterization of two dimethylarsinate-containing molybdenum-oxo clusters, a large, anionic mixed-valence wheel and a small neutral species. The novel compounds were mainly characterized in the solid state by FTIR,TGA, elemental analysis and XPS, and in solution by NMR and UV-Vis spectroscopy.
Microplastics (MP) have received increased scientific, political and societal attention due to their environmental omnipresence. This thesis aims to provide comprehensive data on aquatic MP pollution through the application of state-of-the-art analytical methods, and compares data outputs from two data pipelines.
Within the River Weser–North Sea transitional system, small MP (<500 µm) predominated, with a notable abundance of suspected paint particles. Large MP (>500 µm) exhibited low abundances, mainly composed of the common plastic polymers polyethylene and polypropylene. The estuary’s turbidity maximum zone showed the highest MP concentrations, then declining towards the North Sea, possibly influenced by increased vertical and horizontal export or dilution in the larger marine water body. Additionally, this thesis evaluated two wastewater treatment plants as potential riverine MP point sources. Interference by post-processing residual material required an adaptation of the FTIR reference database by the inclusion of new reference material. Results showed that polyolefins were prevalent in the effluent, and that observed temporal patterns in MP concentrations could be partially explained by technical and environmental parameters. Input of MP into the River Weser via effluent is likely, necessitating more research to understand the full dynamics of MP pollution within this river system. Furthermore, the MP analysis pipeline comparison study showed discrepancies for certain polymer types, possibly due to different polymer grouping methods, or overestimation effects. By excluding these polymer types, both datasets generally were in accordance, suggesting a harmonization of both pipelines should be undertaken to improve comparability of MP data.
In summary, this thesis provides a detailed foundation for understanding MP dynamics in the River Weser–North Sea system and highlights methodological challenges inherent in the field of MP pollution research.
In this thesis, we discuss the properties of quantum antiferromagnetic spin chains with long-range (LR) tunable interactions and positional disorder. By long-range, we mean that the range of interactions falls-off as a power law with the distance. We mainly focus on the entanglement properties of these systems and consider both ground state and high-energy eigenstates.
Additionally, the dynamical properties of the LR random spin chain are considered by investigating the post-quench entanglement growth as a function of time. Finally, we study the response of this system to a local perturbation by considering the quantum fidelity variations with system size.
While analytical results for LR interacting disordered systems are not abundant in the literature, we achieve the implementation of strong disorder renormalization group(SDRG) procedures (and variants) on such models. We systematically confront our results with numerical exact diagonalization(ED) to confirm the obtained predictions.
The contribution of the chemical enhancement mechanism to the SERS process has been studied using a Kretschmann configuration (KC) with a thin silver layer attached to the totally reflecting surface for reproducibility of the results. After studying fundamental properties, additionally, the KC was applied for specific applications.
The basic KC setup has been optimized and the observed enhancement was investigated in detail. SERS studies have been performed on a monolayer of Nile blue, Crystal Violet, and 4-Nitrobenzenethiol. Under resonance conditions for the coupling of the light to the surface plasmons, a decay of the Raman line intensities has been observed over time, converging to constant signal levels. By analyzing this time-dependent intensity variation for the single vibrational modes, we found a mode-dependent Raman deactivation rate. This process has also been investigated for different angles of incidence of the beam (varying the resonance condition), and a clear dependence on the strength of the coupling to the plasmons for the behavior of the different Raman lines has been found. Although, a uniform enhancement of the electromagnetic fields of exciting and scattered light can be assumed for a given angle of incidence when considering the electromagnetic enhancement (EME) mechanism, which usually dominates the SERS process, the relative enhancements were found to be strongly mode-dependent, which is a clear indication of an electronic effect. Obviously, the KC allows for the observation of a dominating chemical enhancement (CE) in these single-layer SERS experiments.
Knowing that only chemisorbed molecules should contribute to the CE, we switched this mechanism off by introducing an isolating interim layer such as Octadecanethiol, 4- Nitrobenzenethiol, or MoO2 between the metal substrate and the molecules (Nile Blue). The intensity ratio between the signals taken under resonance and off-resonance conditions was significantly reduced even when these interim layers were only few nanometers thick where EME should not be considerably affected. This was supporting the assumption that CE is the major contribution in the KC SERS experiment.
Due to the domination of the CE, which only involves chemisorbed molecules, the KC SERS arrangement appears to be attractive for applications where thin layers of molecules have to be studied. As an example, we have demonstrated the detection and quantization of a low concentration (100 nM) of Moxifloxacin (Moxi).
Non-domesticated Saccharomyces yeasts have promising brewing characteristics for beer diversification particularly when used in the generation of de novo interspecific hybrids. Here, non-cerevisiae Saccharomyces interspecific hybrids are explored in wort fermentations for exotic lagers and non-alcoholic beers with complex aroma profiles. Maltose and maltotriose utilization, typically associated with domesticated ale/lager brewing strains, were found in multiple Saccharomyces isolates using high-throughput screening. Saccharomyces mikatae successfully grew on maltotriose as the sole carbon source, a trait until recently unidentified for this species and only recently demonstrated in Saccharomyces jurei, another “wild” species of the clade. Remarkably, de novo hybrids between maltotriose-utilizing S. mikatae/S. jurei and the maltotriose-negative Saccharomyces eubayanus displayed heterosis on maltotriose outperforming both parents. The hybrids were only able to ferment maltose in lager brewing conditions; nevertheless, favorable fruity esters were produced. This study shows that novel hybrids can add to the diversity of lager brewing. Strains unable to grow on either sugar were identified, making them suitable candidates for brewing low-alcohol beers. Wort fermentations hinted the potential for low-alcohol brewing using novel maltose/maltotriose negative Saccharomyces hybrids producing low levels of off-flavors with one S. arboricola isolate highlighted for future studies. Interspecific Saccharomyces hybrids are sterile, hindering genetic analysis of traits of interest. One desired trait in lager brewing is cold-tolerance, with alternative hybrid combinations utilizing cold-tolerant yeasts possible. The cold-tolerance of Saccharomyces arboricola was investigated by successfully restoring fertility in Saccharomyces cerevisiae x S. arboricola hybrids and mapping quantitative trait loci (QTL) responsible in a multigeneration population with a focus on mitochondrial-nuclear interactions. QTL were successfully mapped in the S. cerevisiae genomes of the hybrids with the majority exclusive to specific mitotype. QTL in S. arboricola were not mapped due to lower diversity in the strains used. The method described here provides valuable lessons toward unraveling genetic determinants behind brewing traits in Saccharomyces hybrids.
This thesis focuses on the biogeochemical interactions and behaviors of dissolved organic matter (DOM), metal bioaccumulations, and iron species in the Kairei and Pelagia hydrothermal vent fields in the Indian Ocean. Deep-sea vents have recently been identified as sources of DOM and dissolved metals in the ocean but the knowledge of their fates and their roles in global geochemical cycles is still scarce.
DOM compositions show that both vents are sources of DOS and reduced DOM in the Indian Ocean deep water. DOM compositions of both vent hot fluids were different than those which had undergone thermal abiotic alteration/degradation in previous experiments. This implies that additional processes and/or chemical reactions are involved during hydrothermal circulations.
In term of Fe stabilization and transportation, the results indicate that Fe(II) is the dominant Fe species in all hot fluid samples. Fe(III) becomes prominent in all diffuse fluids which indicates sub-seafloor mixing of endmember fluids with seawater. High [DFe] were observed in both vent plume samples. The voltammetric titrations reveal that Fe organic ligand complexes found in the plumes play a significant role in driving Fe mobilization and bioavailability in the deep water.
In both vents, dense benthic communities were found. Four ubiquitous benthic species were selected i.e., mussels (Bathymodolus septemdierum), scaly-foot snails (Chrysomallon squamiferum), shrimps (Rimicaris kairei) and crabs (Austinograea rodriguezensis) for the metal bioaccumulation study in the different tissue types. Most chalcophile elements are mainly accumulated in the organic tissues of the animals. Different degrees of metal partitioning were also observed between the various tissues and organs. High accumulations found in both vent benthic organisms suggest that the animals possess a similar advanced ability to acclimatize to high-and steady metal exposures like vent organisms in the Atlantic and Pacific Oceans.
For almost 40 years, difluoromethylene phosphonates – compounds of general formula RCF2P(O)(OR)2 – have attracted much interest as molecular tools to study enzymes and their behavior in biochemical processes.
First, we discuss the chemistry of difluoromethylene phosphonates through the prism of its historical development and with an emphasis on general synthetic methods, highlighting the existing challenges and unsolved problems.
We then explore the formal [3,3]-sigmatropic rearrangements of 2,3,3-trifluoroallyl phosphates leading to isomeric 1,1,2-trifluoroallyl phosphates under thermal and Lewis acid-promoted reaction conditions. Although the products of these rearrangements were unstable, the insights we gained while studying these reactions prompted us to explore similar formal [2,3]-sigmatropic rearrangements of 2,3,3-trifluoroallyl phosphorus (III) compounds.
Finally, we describe the newly developed method for the preparation of CF2–P (V) phos- phonate analogs – difluoromethylene phosphonic and phosphinic amides, and phosphine oxides. The method is based on a formal [2,3]-sigmatropic phospha-Wittig rearrangement of readily available fluoroallyl bis(amido)phosphites, amido(aryl)phosphonites and diarylphosphinites. It allows for the preparation of title compounds in a straightforward fashion on a multigram scale, complementing the existing phosphoryldifluoromethylation methods. A powerful one-pot multistep protocol has been developed based on this method. It utilizes ubiquitous starting materials, such as THP-O-protected 2,2,2-trifluoroethanol, directly furnishing phosphonic, phosphinic and phosphine oxide analogs of α,α-difluoro-β-ketophospho- nates without the need for isolation and purification of the intermediate products. Besides providing access to unique compounds hardly accessible through other routes, the developed method benefits from the fact that, unlike most other existing general methods, it does not rely on ozone-depleting HCF2Cl and CF2Br2.
The threats posed by climate change require fundamental changes in the nature of the operation of power grids. The increase in fluctuating sources of renewable energy requires flexible and fast-acting control, data processing, and market adjustments. In turn, these lead to complex nonlinear interactions and non-trivial collective fluctuations, which require sophisticated methods of analysis. This dissertation reports on work using a variety of methods from statistical physics to extend the applicability of methods that are already commonly used in control engineering, machine learning, and economic analysis. First, we use the Belief Propagation algorithm (BP), an efficient local algorithm for Bayesian inference, optimization and network analysis, which improves upon Curie-Weiss mean-field theory by taking local correlations into account. We apply the algorithm to statistically analyze conditions under which an accurate estimate of power flows can be obtained from noisy and incomplete measurement sets, and show that it can be used for effective dimensional reduction of power grids. We derive a novel implementation of BP for supply networks, which strongly enhances its convergence and accuracy, explicitly demonstrate its applicability to power grid state estimation and natural gas pipeline network analysis, and discuss further applications to supply networks. Secondly, we map traders' abuse of reserve energy to a minority game and study it using agent-based modeling and the cavity method. The cavity method improves upon Curie-Weiss mean-field theory by including backreactions between traders and market prices, and is formally an approximation on the same level as BP. We show that for this application the cavity method has a natural interpretation in terms of self-consistent linear response. We derive policy recommendations by showing the effectiveness of penalties on large contributors to the abuse of reserve energy, and by demonstrating that external noise is [...]
Pistacia is part of the Anacardiaceae family. Pistacia vera is the only genus within the 11 Pistacia geniuses that produces nuts large enough to be used commercially. Pistachios were originally cultivated in Iran and much later, were introduced to California. The nutrients contained in pistachio are responsible for their potentially beneficial influences on human health. Numerous studies reveal that nut intake is accompanied by a wide range of health benefits, including the modulation of antioxidant, anti-inflammatory activities, due to the presence of bioactive compounds including lipids (unsaturated fatty acids, sphingolipids, phytosterols), dietary fiber, plant protein, carbohydrates, antioxidants, vitamin E, arginine, as well as minerals (potassium, calcium, and magnesium). The pistachios have long been used for health and medicinal purposes, and have unique properties, for example improving cardiovascular health, due to pistachios’ ability to decrease cholesterol levels, and reduction of glucose in diabetes. The lipid fraction of Pistachio nuts of various origins were characterized by high resolution and tandem mass spectrometry coupled to high performance liquid chromatography. Total lipid content was determined as a sum parameter gravimetrically. Based on mass spectrometrical data more than 100 triacylglycerides (TAGs) could be identified, the majority of them for the first time from this source. Complementary measurements using the FAME method based on gas chromatography revealed the presence of 26 fatty acids as building blocks for the TAGs. Selected pistachio lipid samples showed the presence of oxygenated TAG bearing epoxy, hydroxy and peroxy moieties. HPLC-MS measurements based on high resolution and tandem mass spectrometry allowed structure elucidation. These compounds are unique to pistachio. The unusual complexity of the pistachio lipidome prompted the development of novel bioinformatic strategies for compound assignment.
