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Understanding Patients and Mental Health during the COVID-19 Pandemic thru a Psychological Lens: Needs, Resources and Implications
No full textThe COVID-19 pandemic as a crisis has been associated with changes in daily interaction, social connectedness, mental health, support structures, and the provision of (mental) health care treatment. This thesis aims to examine 3 main targets: psychological well-being during crises, psychological mechanisms related to reactions and consequences of individuals and systems, and the effectiveness of digital interventions to support mental health.
In 5 studies the following were examined: (1) triggers of preventable adverse events (pAEs) through evaluating the psychometric properties of a questionnaire; (2) hand hygiene behavior along the Health Action Process Approach (HAPA) through structural equation modeling; (3) differences in worries and mental health of the general population and psychosomatic rehabilitation patients; (4) evaluation of the intercorrelation between psychological variables along the Evolutionary Theory of Loneliness via a serial mediation model; (5) evaluation of the effectiveness of digital (psycho)therapeutic interventions.
In study 1, 5 areas of triggers of pAEs were defined and the questionnaire showed good psychometric properties. Study 2 has shown that hand hygiene behavior could be explained along the HAPA with the pattern being invariant for mental health. Study 3 has demonstrated higher mental health-related symptoms for psychosomatic rehabilitation patients who also reported different worries than the general population. Study 4 has shown a serial and individual mediation effect of loneliness and anxiety between distress and depression. Adding digital interventions to the traditional therapy approach supported the reduction of psychological symptoms as shown in study 5.
The findings of this thesis contribute to a greater understanding of psychological mechanisms evaluated by reactions and consequences associated with the COVID-19 pandemic and allow for several practical, theoretical, and methodological conclusions to be drawn
Biochemical studies of the social amoeba Dictyostelium discoideum
No full textThe amoeba Dictyostelium discoideum is a versatile and genetically tractable model organism used in research for many cellular processess. This work is focused on the biochemical study of two different processes in the amoeba.
The first part was the establishment of monitoring techniques for viral infections in the amoeba. For this purpose, two detection method should be established: a qPCR-based assay for the counting of the Acanthamoeba polyphaga mimivirus (APMV) genomes and it was observed that no net increase occurred in D. discoideum AX2 cells. APMV is taken up into the amoeba, however, the number of viral particles decreased until 6 hours post infection (hpi), indicating that APMV was not able to enter the replicative stage, possibly failing in the phagolysosomal pathway. Infection of phagolysosomal mutants indicated that lysosomal enzyme might be key in the defense against APMV.
The second part covers the potential ribosome heterogeneity during development of D. discoideum with a focus on the 2´-O-methylation (2´-O-Me) and pseudouridylation (Ψ). Both chemical modifications are introduced sequence-specifically by box C/D and box H/ACA small nucleolar RNPs (snoRNPs), respectively. Using bioinformatics and RNAseq analysis, 30 novel box C/D snoRNAs were identified, however, in silico approaches failed to deliver box H/ACA snoRNA candidates. Modified nucleotides were determined by the application of RiboMeth-seq for 2´-O-Me and HydraPsiSeq for Ψ. Several 2´-O-Me and Ψ sites were found to be substoichiometrically modified and some positions displayed dynamic modification levels during the development of the amoeba. Experiments and previous data on the U3 snoRNA implied a sudden generation of novel and potentially specialized ribosomes during development. Taken together, the presented data from D. discoideum is the first evidence for ribosome heterogeneity in the Amoebozoa supergroup, allowing to suggest that it is a common feature of all eukaryotes
Biogeochemical interactions of metals, organic matter, and hydrothermal organisms in two vent fields of the Indian Ocean ridge system
No full textThis 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
Introduction Strategy for Lean Methods - System Dynamics Approach
No full textThe overreaching aim of this paper is to introduce a strategy for lean methods implementation in production systems. The first sub-objective is to describe the lean manufacturing philosophy and discuss research findings on the topic of lean methods and their impact on production system performance. The second sub-objective is to develop a system dynamics model based on the findings obtained through literature review. The third sub-objective is to analyze the results and derive recommendations for lean methods implementation that will ensure long term continuous performance improvement
Electronic and Transport Properties of Novel Two Dimensional Materials
No full textThe family of 2D layered materials has gained enormous attention of materials scientists and researchers from other fields of science. This stems from the fact that 2D monolayers (1Ls) can exhibit remarkably different electronic properties than their bulk counterparts. Moreover, stacking different 1Ls, results in yet different electronic properties than these of the 1Ls. Recently, among others, van der Waals heterostructures (vdW HS) of transition-metal dichalcogenides (TMDC) have been extensively studied due to their type-II band alignment.
This thesis summarizes four different theoretical studies on layered 2D materials. The first study investigates the potential existence of a new family of bulk layered materials with chemical formula XY3 (where X = group 14; Y = group 15). The low cleavage energies indicate the potential exfoliation as mono- and bi- layers (2Ls), where most of the exfoliated layers are thermally and dynamically stable. Interestingly, many 1Ls and 2Ls show strong quantum confinement and turn into indirect semiconductors, unlike bulks which are all metals. Such metal to semiconductor transition was previously known for noble-metal dichalcogenides. Next study shows one of the potential applications of XY3, that is, single-material logical junction for gas sensing applications. A device that consists of metallic multilayers (3L) as electrodes and semiconducting 1L as scattering region. To do so, one of the exemplary materials (SnP3) was picked to construct a single-material device. The results combining density functional theory (DFT) and non-equilibrium Green’s function (NEGF) calculations revealed that SnP3 is an ideal material for gas sensing applications, especially for poisonous NO gas molecules. For NO molecules, this device showed a negative differential resistance (NDR) at small bias voltages.
Moreover, electronic properties of vdW TMDC HS were investigated for the HS having up to six layers. In this part, it was essentially studied [...
Characterization of Pistachio lipids and polyphenols
No full textPistacia 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
Biodiversity related (meta)data and their link to the Nagoya protocol: Integrative and semantic efforts towards FAIR data reveal and address data challenges around the Nagoya policy framework
No full textNowadays, with the environment and climate changing, there is a vast amount of research data being produced as part of environmental and biological studies in order to gain foundational knowledge to help sustainability and nature conservation. Biodiversity research on all scales deliver a wide range in variety of data types, speed of data generation and storage volume, which requires comprehensive management on many levels. This leads to a complex environment which is only controllable by detailed planning and long-term management of such data. Official guides to best practice data handling and several internationally agreed standards aid an intelligent integration of information. Legal frameworks, such as the “Nagoya protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization”, are in place to improve clarification on data handling conditions and restrict biopiracy. However, even though there are guidelines and best practices on how to handle diverse data throughout its lifecycle, the heterogeneity and patchiness of data available from open public archives and databases pose a problem for information extraction to an end user- it is a challenge to retrieve information from unstable, decentralized data sources.
In this thesis a previously developed Nagoya protocol lookup service prototype was refined for gaps in the data landscape which can be applied by various stakeholders.
A representational proof-of-principle ontology was developed to add to the comprehensiveness of the knowledge representations available to stakeholders. This ontology (NagO) is focused on the United Kingdom, its external territories and their link to the Nagoya protocol. It is a demonstration of a consolidated, open knowledge source for legal, document, sovereignty and Nagoya protocol matters, which to date are only retrievable from various different sources including web searches, fact sheets, experts and governmental authorities
Dynamic Safety Stock Considerations - A simulation based comparative analysis
No full textThe focus of the study is to conduct a comparative analysis of the most widely adopted methods of safety stock calculation. Firstly, it aims to identify the most widely adopted methods of safety stock calculation and investigate their strengths and weaknesses. Secondly, the thesis aims to analyse the demand patterns that operations managers often encounter and their behaviours. The safety stock calculations will then be compared to one another by running a simulation with different demand patterns using each of them. Finally, recommendations will be made on which demand patterns, if any, each of these methods is best applied to
Distributed Ledger Technologies for the implementation of PES schemes
No full textPayments for Environmental Services (PES) are economic mechanisms to compensate actors for providing environmental services.
Distributed Ledger TEchnologies (DLTs) are a system of electronic records that enables a network of independent participants to establish a consensus around a set of transactions. They are distributed databases organised as a chain of ordered information blocks, recorded by a network of computers.
DLTs enable the appearance of innovative applications (such as smart contracts, tokens, wallets and programmable money) to tackle recurrent PES issues and implement PES design advice found in the scientific literature. They also promise to facilitate new collaboration infrastructures for independent actors that pursue a common environmental goal. Through a common authoritative ledger that serves as a synchronizing backbone for managing interactions between independent network participants, DLTs enable coordinated collaboration efforts based on the transparent transaction of financial resources, the collective management of information regarding the state of the environmental resources and the management of activities that impact its transformation.
This study investigates how blockchain technologies might contribute to the success of PES schemes by lowering information asymmetries and transaction costs, by enabling the appearance of blockchain-supported applications that tackle specific PES deficiencies and by providing new institutional alternatives for governing the interaction of individuals for a common (environmental) purpose.
This study proposes that blockchain-supported applications are likely to improve current PES schemes by making them more transparent, by reducing the costs associated to maintaining trust and by reducing the need for certain intermediary services. It also envisions new types of peer-to-peer payments for environmental services emerging as a consequence of decentralization and distributed ledger technologies
Determining Possible Roles of Thyroid Hormone Transporters in Non-Canonical Regulation of Thyroid Gland Function
No full textWhile altered thyroid phenotypes can arise due to cathepsin deficiencies, functional compensation via the upregulation of cathepsin L, despite normal serum thyroid stimulating hormone (TSH) levels, in cathepsin K-deficient (Ctsk-/-) mice is unexpected. Furthermore, these mice show normal serum thyroid hormone (TH) status by increased monocarboxylate transporter Mct8-mediated TH export. Thus, alternative thyroid regulatory mechanisms that are independent of the canonical hypothalamus-pituitary-thyroid axis might exist, making Ctsk-/- mice a suitable model to study “thyroid auto-regulation”. The first part of the present study elucidates the possible roles of Mct8 and Mct10 in non-canonical regulation of cathepsin-mediated thyroglobulin (Tg) proteolysis. We assessed the thyroid phenotypes in combined cathepsin K and TH transporter deficiency, i.e., in Ctsk-/-/Mct10-/-, Ctsk-/-/Mct8-/y, and Ctsk-/-/Mct8-/y/Mct10-/- mice. Results revealed that induced lysosomal biogenesis due to autophagy, possibly triggered by thyrotoxicity, causes persistent Tg proteolysis in a counterintuitive manner in Mct8-deficient genotypes. The second part of the study examines the factors triggering autophagy in the Ctsk-/-/Mct8-/y/Mct10-/- murine model. Since Lat2 regulates autophagy in kidney and pancreas, we propose that Lat2 regulates autophagy in thyrocytes as well. Indeed, Lat2 protein amounts were significantly decreased in autophagy-induced Ctsk-/-/Mct8-/y/Mct10-/- mice. Furthermore, Lat2-/- thyroid glands showed autophagy induction and lysosomal biogenesis. The third part of this study explores whether altered TSH receptor localization can lead to differences in thyroid gland architecture. Results revealed that Mct10 deficiency results in vesicular TSH receptors as opposed to canonical basolateral TSH receptors in controls. Although altered TSH receptor localization does not result in gross alterations in thyroid gland morphology, thyrocyte survival is possibly regulated by Mct10