Coming dissertations at Uppsala university
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Exploring Reaction Pathways in Li-ion Batteries with Operando Gas Analysis
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-522294
The reliance on Li-ion batteries is increasing as we transition from fossil fuels to renewable energy sources. Despite their widespread use, a gap remains in understanding certain processes within these batteries, especially regarding the solid electrolyte interphase (SEI) and the impact of side reactions on Li-ion batteries. A custom-made Online Electrochemical Mass Spectrometry (OEMS) instrument was designed to explore these aspects. The OEMS instrument was validated through the study of gas-evolving reactions in the classic LiCoO2 | Graphite system. In-depth studies focusing on the reaction pathways of ethylene carbonate, the archetype Li-ion battery electrolyte solvent, identified the specific reaction pathways contributing to SEI formation. Moreover, ethylene carbonate’s interaction with residual contaminants like OH– from H2O reduction was explored. It was revealed that the integrity of the SEI can be compromised by minor amounts of contaminants, establishing a competitive dynamic at the negative electrode surface between ethylene carbonate and residual contaminants such as H2O and HF. Additionally, the roles of additives like vinylene carbonate and lithium bis(oxolato) borate in SEI formation were explored. Vinylene carbonate was shown to form a layer on the negative electrode, but also scavenge protons and H2O, revealing that it is a multi-functional additive. Lithium bis(oxolato) borate on the other hand formed an SEI layer before H2O reduction, blocking the residual contaminant and ethylene carbonate from reaching the electrode surface. By providing insights into the negative electrode’s interphase and SEI formation through a custom-made OEMS instrument, this research underscores the complexity of reaction pathways and the necessity of considering both major and minor, as well as, primary and secondary reactions for a holistic understanding of Li-ion batteries.
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Function and Evolution of Small Regulatory RNAs and their Associated Proteins : A Journey from Genome to Proteome
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-522164
Organisms throughout the tree of life have evolved distinct ways to regulate gene expression. Some of these processes involve non-coding RNAs (ncRNAs), which are not translated but functional nonetheless. These ncRNAs are of utmost importance, with dysregulation of some causing severe developmental effects or even being lethal.
In order to get a better fundamental understanding of gene regulation, and the ncRNAs that evolved to regulate gene expression, we study this in Amoebozoa. Members of this taxon vary greatly in lifestyle and organismal complexity. Some are strictly unicellular, free-living, whereas others, such as the social amoeba Dictyostelium discoideum can transition between unicellular and multicellular lifestyles.
D. discoideum features a variety of small ncRNAs. Among these are the microRNAs. microRNAs have mostly been studied in plants and animals, where they are believed to have evolved convergently, and hypothesized to have played a role when these taxa evolved multicellular lifestyles. At what point the D. discoideum microRNAs evolved, how they function, and if they are involved in its multicellular lifestyle are fundamental questions addressed in this thesis.
Here, we studied the evolution and function of microRNAs in a broad set of species belonging to Amoebozoa. We could identify microRNAs in all studied amoebae, and concluded that they are probably not involved in the evolution of multicellularity. To in detail investigate the evolution of microRNAs, we performed comparative genomics using D. discoideum and the close relative Dictyostelium firmibasis. For this, we sequenced, assembled and annotated the genome of the latter. At this point, our findings suggest that the microRNAs evolved several times in Amoebozoa, although we cannot rule out if they have a deep evolutionary history.
The Class I RNAs are another type of ncRNAs. These, on the other hand, are only present in the social amoebae. They are hypothesized to regulate the transition from unicellular to multicellular in these species, potentially in a post-transcriptional manner. In order to investigate this, it is essential to understand to what extent the proteome and transcriptome correlate. Hence, we performed paired transcriptomics and proteomics in a time-series during multicellular development. By including a strain in which a specific Class I RNA is knocked out, we have initiated studies of its role during the transition to multicellularity.
In conclusion, we were able to answer broad evolutionary and functional questions about gene regulation and ncRNAs by studying Amoebozoa from genome to proteome.
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Traumatic brain injury in elderly patients
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-521958
The increase of elderly traumatic brain injury (TBI) patients constitutes a considerable challenge. The aim was therefore to specifically study elderly TBI patients with respect to patient characteristics, neurointensive care (NIC) and outcome, and to identify age specific features, which may be important for selection of patients and optimization of NIC in the elderly. Data from the Uppsala TBI-registry and collected physiological monitoring data from the NIC unit were analysed.
Between 1996–1997 and 2008–2009, patients ≥60 years had doubled from 16% to 30%. Despite the increase of elderly an overall favorable outcome was maintained at around 75% between the two periods and the elderly showed favorable outcome in slightly more than 50%.
Analysis of characteristics and outcome between 2008–2010 showed that fall accidents and acute subdural hematoma were more common in the elderly ≥65 years. Admission status and NIC treatment did not differ depending on age, except that a larger proportion of the elderly had surgery. Elderly ≥65 years showed a favorable outcome in 51% compared to 72% in the young.
Studies of patients ≥60 years treated 2008–2014 showed that high age, multiple injuries, low Glasgow coma motor score on admission and the use of mechanical ventilation were negative prognostic factors.
Elderly had different secondary insult patterns with a higher percentage of good monitoring time (%GMT) with high cerebral perfusion pressure (CPP), high mean arteria blood pressure (MAP) and high systolic blood pressure (SBP) and less %GMT with high intracranial pressure (ICP), low CPP and low MAP. On the contrary to the young, high %GMT with SBP>180 was associated with favorable outcome in the elderly, indicating that blood pressure probably should be treated differently in the elderly.
Elderly had worse pressure autoregulation (higher values of PRx) and spent longer time with higher PRx. Elderly also had higher optimal CPP and spent lower %GMT with CPP close to optimal CPP. High PRx correlated with mortality in elderly but pressure autoregulation influenced outcome less in the elderly.
Overall, the results show that elderly TBI patients differ in many aspects and more studies are warranted to increase knowledge and optimize NIC.