Coming dissertations at Uppsala university
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Synthesis and Characterization of Quasicrystals and Approximants : Gaining New Insights on the Local Atomic Arrangements in Quasicrystals and Their Approximants
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-541478
The icosahedral quasicrystal (i-QC), an aperiodic crystal, exhibits non-crystallographic symmetry in three-dimensional space. Its unique structural properties continue to draw significant attention in Condensed Matter Physics. Tsai-type i-QCs for example, have been the focus of extensive research since 2000. However, due to challenges in determining the structure of i-QCs, their exact crystal chemistry and the relationship between their structure and physical properties remains unclear. So-called quasicrystal approximants (ACs) share similar atomic arrangements and chemical compositions with their aperiodic siblings. The exploration of the correlation between structural and physical properties in periodic ACs thus permits to gain deeper insights into local structures that resemble those of QCs, and thus on the crystal chemistry of QCs.
This thesis deepens our understanding of the Tsai-type ACs and QCs, focusing on optimizing synthesis methods and using single-crystal X-ray diffraction (SCXRD) to elucidate the crystal chemistry of ACs. Structural evaluations of various ACs employ elemental tuning and substitution in binary and ternary Tsai-type systems such as Gd-Cd and Gd-Au-Al; the results are connected to the observed magnetic properties.
Chapter 1 provides an overview of QCs and ACs, covering their history, structure, and physical properties to give readers a solid background on the topic. Chapter 2 outlines the synthesis methods and sample characterization techniques used in this research. Chapter 3 presents the key findings, including a detailed structural evaluation of ACs, AC-related superstructures, and more complex AC structures. This analysis clarifies the structural mechanisms associated with phase stability and connect them to their physical (magnetic) properties. Finally, a summary of the thesis main contribution to the research community, and concluding remarks on the chemical insights into the structural and physical properties of ACs and QCs are given in Chapter 4.
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Characterization of differences in clinical parameters and extracellular matrix composition between bicuspid and tricuspid aortic valves : How this can be used to predict outcome and to develop new treatment strategies
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-541638
Bicuspid aortic valve (BAV) is the most common congenital heart disease with an estimated prevalence of 0.5-1.4% in the general population. The condition increases the risk of a number of complications, with aortic stenosis (AS) being the most common, and close to 70% of all patients with a BAV require aortic valve replacement (AVR) during their lifetime.
In study I, 271 consecutive patients (152 BAV AS and 119 tricuspid aortic valve (TAV) AS) with severe AS underwent surgical AVR (SAVR). Preoperative echocardiography revealed that BAV AS patients had more pronounced preoperative systolic and diastolic dysfunction, despite being younger and having less comorbidities than tricuspid aortic valve (TAV) AS patients. Furthermore, the incidence of postoperative HF was higher BAV AS patients, while all-cause mortality during follow-up was similar for BAV AS and TAV AS patients.
In study II, 227 consecutive patients (133 BAV AS and 94 TAV AS) with severe AS underwent SAVR. The incidence of postoperative atrial fibrillation (POAF) and its association to preoperative left atrial (LA) reservoir strain was investigated. The incidence of POAF was similar for BAV AS and TAV AS patients, but there was a significant interaction between aortic valve morphology and LA reservoir regarding POAF. Furthermore, BAV AS patients had a higher incidence of persisting POAF and cumulative ischemic stroke incidence during follow-up after SAVR.
In study III, the incidence of new-onset conduction disturbances (new-onset third-degree atrioventricular (AV) block or new-onset left bundle-branch block (LBBB)) was retrospectively investigated in 1147 patients (589 BAV AS and 558 TAV AS) with severe AS that underwent SAVR. The incidence of new-onset conduction disturbances was higher in BAV AS patients. New-onset LBBB was associated with a worse long-term prognosis after SAVR. Bicuspid patients with fusion of the right- and the non-coronary cusps were at greatest risk of developing postoperative conduction disturbances.
In study IV, aortic valve tissue was collected from 88 patients who underwent aortic valve surgery. Proteomic analyses of the excised valves showed that the extracellular matrix (ECM) composition in BAV and TAV patients differs significantly. The ECM of BAV patients is abundant with fibrosis markers, while the ECM of TAV patients is abundant with inflammatory markers.
In conclusion, this thesis demonstrates that BAV AS and TAV AS patients are two distinct patient categories with different clinical characteristics that translates into different risks of postoperative complications.
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Perspektiv på efternamnsbyten : Motiv och mönster i ansökningar åren 1925–2015
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-541212
In this thesis, I examine surname change applications in Sweden for a selection of years between 1925 and 2015 and conduct interviews with recent surname changers. My aims are first to investigate why people change their surnames, second to study how important the surname has been for a sense of community within the family, and third to investigate the extent to which name changers have created their new names themselves. How these topics have developed over time is discussed in relation to changes in Swedish society. The results show that surname changes are motivated by a rather complex network of reasons with a multitude of interrelated factors. The most common reasons stated in applications are being mistaken for other people with the same surname, practical problems with pronunciation and spelling, and/or various life events, such as before a wedding, after a divorce, or when moving to a new location. During the latter part of the 20thcentury, an increasing number of name changers mention a wish to achieve or avoid surname community with specific family members. Based on the concept of collective and individual identity, the thesis suggests that surname community has been and remains important within the nuclear family, but has become less important among adult siblings. The results also indicate that surnames have been used to a greater extent to promote individual identity in late 20th century Sweden. During the late 20th and the early 21st century, surname changers seem to have created their own surnames to a greater extent. In the early and mid-20th century, they were more inclined to select names from lists of suggested surnames issued by the state and private companies. Drawing on theories of indexicality, the thesis suggests that in Sweden surnames are and have been used, on the one hand, to promote both tradition and modernity, and, on the other hand, to promote both closeness and distance.