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Disputationer

Via universitetsbibliotekets databas över doktorsavhandlingar kan du söka publicerade doktorsavhandlingar vid Göteborgs högskola/universitet från 1902 och framåt. Databasen innehåller också information om kommande disputationer.

UB:s databas över doktorsavhandlingar

Kommande disputationer

Wooden objects in historic buildings: Effects of dynamic relative humidity and temperature

[2017-11-24] Title: Wooden objects in historic buildings: Effects of dynamic relative humidity and temperature Authors: Bylund Melin, Charlotta Abstract: Cultural heritage objects and interiors are found not only in museums but also in historic buildings, often with less climate control. The indoor environment in such buildings may be colder and more humid, and can fluctuate. The research presented here aims at better understanding the effect of such dynamic indoor environments on wooden objects housed in them. There are five papers covering three complementary parts of this research project: 1) Paper I examined how existing recommended climate ranges are interpreted and used by the cultural heritage sector, using two risk-assessment websites. The risk for wooden objects was interpreted by the two websites using data from buildings with different degrees of climate control. The two websites showed low agreement for the risk of mechanical damage in historic building environments, suggesting that knowledge of dynamic environments and the influence of low temperatures are not sufficiently studied. 2) Papers II and III aimed to relate damage of painted wooden objects to past and present indoor environments in historic buildings, starting with whether such damage to painted pulpits in churches can be related to past and present energy consumption. The total heat output 1900-1990 was revealed from archives on fuel costs and heating systems of each church and used as a proxy for energy consumption. These data were correlated with damage assessments performed for the painted wooden pulpits in each of the churches. Results suggested that more damage, in terms of craquelure in the paint layers, was present in churches with a higher heat output and there was increased damage in churches which used background heating compared to churches which did not. 3) Papers IV and V aimed to record moisture diffusion in wood and hence the impact of dynamic environmental conditions. Various indoor environments were simulated in a climate chamber using the selected method to estimate the rate and distribution of moisture in wood over time. Low temperatures were shown to reduce moisture transport and increase response delay, resulting in a smaller mechanical impact on wood. The thesis shows that low temperatures are beneficial for the preservation of wooden objects. While lower temperatures could help in saving energy on climate control in historic buildings, the results need to be validated. Further research projects are required linking field studies, laboratory experiments, analysis and modelling.

Immunological and Microbiological perspectives on Irritable Bowel Syndrome.

[2017-11-24] Title: Immunological and Microbiological perspectives on Irritable Bowel Syndrome. Authors: Bennet, Sean Abstract: Abstract Irritable bowel syndrome affects ~11% of the population in the Western world and is characterised by altered bowel habits and abdominal pain. The range of additional symptoms between subjects makes groups of IBS patients heterogeneous. Increased immune activity, altered gut microbiota and diet are implicated in symptom generation though the mechanisms are poorly understood. Moreover, gut microbiota and immune activity interplay in relation to symptoms requires elucidation and while dietary intervention is effective in some patients its impact on gut microbiota is unclear. Most likely, all patients do not share the same symptom generating mechanisms, and thus better means to stratify patients for both research and treatment is required. This thesis aimed to demonstrate how gut microbiota, the immune system and their crosstalk result in symptom generation in IBS patients. Furthermore, we aimed to demonstrate how dietary intervention affects microbiota of the gut and if patient responsiveness to intervention therapy could be predicted by gut microbiota profiles. This thesis demonstrates that a diet low in poorly absorbed carbohydrates (FODMAP) changes the gut microbiota composition and reduces beneficial bacteria in IBS patients. Moreover, the composition of gut microbiota can be used to discriminate patients whose IBS symptoms improved or not after a low FODMAP diet. Additionally, serum or mucosal cytokines cannot be used alone to diagnose IBS. However, a subset of immuno-active patients had comparatively raised serum levels of pro-inflammatory cytokines to healthy subjects and immuno-normal IBS patients, although no major associations between cytokines and symptoms were found. Further, IBS patients had an altered mucosal expression of genes associated with an innate antimicrobial response compared to healthy subjects. The antibacterial gene expression response profiles as well as faecal and mucosal bacterial profiles were different between immuno-active and immuno-normal IBS patients, but were not associated to symptoms. In conclusion, a subset of IBS patients has altered immune activity, deemed by cytokine and innate antimicrobial response profiles, which do not seem to be associated with any specific symptom profile. Further, faecal microbial profiles may be used to identify responders to low FODMAP diet therapy but negative impact of the diet on beneficial bacteria requires further investigation. Thus, this thesis has identified novel subgroups of IBS patients based on underlying mechanisms which may guide development of innovative therapy options.

Renal perfusion, function and oxygenation after major surgery and in septic shock

[2017-11-24] Title: Renal perfusion, function and oxygenation after major surgery and in septic shock Authors: Skytte Larsson, Jenny Abstract: Acute kidney injury (AKI) is a common and dreaded complication to severe illness and major surgery, with major impact on mor- bidity and mortality. The aim of this doctoral thesis was to increase the knowledge on renal pathophysiology and to explore potential interventions for treatment and prevention of AKI after cardiac surgery, liver transplantation and in early clinical septic shock. Patients and methods: Patients were studied in the intensive care unit (ICU) immediately after surgery, and in septic shock patients within 24 hours from admission to ICU. We studied the renal effects of a crystalloid (Ringers-acetate®) and a col- loid (Venofundin®) fluid as plasma volume expanders after uncomplicated cardiac surgery (paper I, n=30), renal pathophysiology and the renal effects of target mean arterial pressure (tMAP) after liver trans- plantation (paper II n=12, and II, respec- tively, n=10), and renal pathophysiology in early clinical septic shock (paper IV, n=8). Renal blood flow (RBF) and glomerular fil- tration rate (GFR) were measured by renal vein thermodilution and renal extraction of 51Cr-EDTA, respectively. In paper IV, RBF was measured by infusion clearance for para-aminohippurate (PAH). Results: RBF is increased by both crystalloid and colloid fluid when used as plasma volume expander after cardiac surgery, but due to hemodilution, neither of the fluids increases renal oxygen delivery (RDO2). The crystalloid-induced increase in GFR is associated with impaired renal oxygenation, which is not seen with the colloid. After liver transplantation, vasodilation of the efferent arterioles causes a renal vasodilation and a fall in GFR. Renal oxygen consumption (RVO2) is considerably in- creased early after liver transplantation, despite the lower GFR. The increased RBF seen after liver transplantation is not sufficient to meet the increased RVO2, result- ing in an impaired renal oxygenation. Early after liver transplantation, a tMAP of 75 mmHg, compared to 60 mmHg, improves RBF and GFR without impairing renal oxygenation. In early clinical septic shock, there is a fall in GFR and RDO2 caused by a constriction of renal afferent arterioles, ac- companied by a sodium reabsorption at a high oxygen cost, which together with the reduced RDO2 impairs renal oxygenation, causing renal tubular injury. Conclusions: Treatment of hypovolemia with a bolus dose of crystalloid fluid impairs renal oxygenation after uncomplicated cardiac surgery. In liver transplant recipients, renal function is severely reduced and renal oxygenation is impaired due to a high RVO2 not matched by a proportional increase in RDO2. In liver recipients, RBF and GFR are pressure-dependent due to the loss of renal autoregulation at a MAP < 75 mmHg. In early clinical septic shock, GFR and RDO2 are reduced because of renal vasoconstriction, causing impaired renal oxygenation and a tubular injury.

Drama and Learning in Nursing Education. A study in first and second cycle

[2017-11-24] Title: Drama and Learning in Nursing Education. A study in first and second cycle Authors: Höglund Arveklev, Susanna Abstract: Aim: The overall aim of this thesis was to explore and describe the nature of students learning through drama in nursing education, in first and second cycle. Methods: Study I was conducted as an integrative review of the literature. Study II was performed as a qualitative phenomenographic study were 16 nursing students was interviewed. In study III 43 group assignment by nursing students in first cycle were analyzed using Qualitative content Analysis. Study IV was conducted as a qualitative phenomenographic study where 15 nursing students in second cycle was individually interviewed. Results: The findings in study I showed that drama can be used effectively in nursing education to enhance students’ learning. The summarized results of the empirical studies (II–IV) showed that drama enabled the students to learn about themselves and develop a higher self-awareness. Learning through drama also gave the students opportunities to learn about others by exploring the perspectives of colleagues, patients, and patients’ next of kin in fictive nursing situations. The findings showed in addition that drama could make the theoretical course content more concrete and easier to grasp. Learning through drama activated the students’ learning by offering them the possibility to be active and explore various roles and scenarios, and by promoting reflection in which they could share experiences with their peers. By participating in drama, the students reached an evolving identification with the profession of a nurse (II–III) and of a specialist nurse in paediatric care (IV). Conclusion: Drama in nursing education has the unique potential to prepare nursing students in both first and second cycle for their future nursing role. Through drama, students are given the opportunity to explore and gain knowledge about how to use theoretical knowledge in practice, about their inner selves, and about other person’s perspectives.

Interpretations of old wood. Figuring mid-twelfth century church architecture in west Sweden

[2017-11-23] Title: Interpretations of old wood. Figuring mid-twelfth century church architecture in west Sweden Authors: Linscott, Kristina Abstract: This thesis explores mid-twelfth century church architectures in west Sweden. The architectures are investigated in the light of a case, five parish churches’ naves, in particular their attics and surviving mid-twelfth century roofs. Working from the insight that these roofs were most likely visible from the rooms below, the thesis presents in-depth analysis of the sites, buildings, and their organisation of forms and volumes. The archaeological evidence is approached with architectural perspectives, and the study brings together a partly new view of the mid-twelfth century church architectures. The churches’ attics and roofs have seldom been in the focus in studies that interpret the historical church architectures. Thus, even if the uniquely old roofs are well preserved, we understand only fragments of how they may have been significant. The naves were created in a period before we have specific documentary evidence. Thus, as a study system, the idea that the archaeological physical remains establish ‘iterated, performed, articulations’ guide the work throughout. The physical evidence is approached with architectural perspectives. The historical architectures are viewed as a matrix for peoples’ beings and doings, which means that the architectures were both essential, present ‘everywhere’, and routine, ‘everyday’. The thesis presents relationships between the remains and architectural perspectives. Based on investigations in the buildings, and a 3D laser scan of one church, the analysis first focus on walls and roofs respectively and thereafter explores relationships between these. The interpretations show that the naves’ masonry walls formed a firm and ‘cave-like’ setting, and that the roofs contrasted with a light and ‘lively’ character. The roof in one nave, in Gökhems’ church, articulates or marks ‘zones’ in the room below, interpreted as the ‘west’, ‘middle’ and ‘east’. Thereafter the thesis focus attention on four architectural themes in a sequence of events, i.e. ‘discovery and approach’, ‘portal and doorway’, ‘entry and exploration’ and finally, ‘recalled in visual memory’. In these, the focus is on the same church in Gökhem however, some investigations connect to stave churches in Norway, as well as to a woven picture of a church, in a tapestry from north Sweden. In the last part, the thesis cast light on some important subsequent changes. The results provides a basis for future projects, pointing to the importance of the wooden built remains in Sweden and Norway, working from ‘site topology’, and analysis of medieval built environment from the viewpoint of preserved textiles. The five churches are part of a Swedish national heritage and they were, together with many other small churches in Sweden, extensively restored during the twentieth century. In this process, they lost some of their local diversity. As we now try to fit these monuments, which have a national identity, into an increasingly complex world with many identities, new understandings of the churches’ varying pasts are important. The thesis seeks to strengthen archaeological and architectural perspectives within conservation, and argues to include roofs as particularly significant, in future monument assessments.

Fitness, cognition and cardiovascular disease. Epidemiological studies.

[2017-11-23] Title: Fitness, cognition and cardiovascular disease. Epidemiological studies. Authors: Lindgren, Martin Abstract: Abstract Physical activity and fitness have well established health bringing benefits. Low soci-oeconomic status is a known risk factor for cardiovascular disease. This association is commonly attributed to individual factors such as educational attainment, supposedly bringing about health-related behaviours. However, individual factors do not fully account for the observed health disparities, demanding further investigation. The aims of this thesis were to investigate how physical activity and fitness varies according to neighbourhood socioeconomic status among middle-aged individuals in the Gothenburg region, using data collected for the SCAPIS-pilot study in 2012. Additional aims were to identify the role of factors related to fitness and cognitive function in the development of heart failure and cardiovascular disease in youth, with an extended follow up via population registries. For this purpose, we used data from the Swedish military service conscription registry, containing information of about 1.8 million Swedish men. We separately studied the association between cardiorespiratory fitness, muscle strength, resting heart rate, and cognitive capacity for future cardiovascular disease, recorded in the national inpatient- and cause of death registries. Data from the SCAPIS-pilot showed that inhabitants of low-SES areas have a lower general activity level, lower rate of fulfilment of the national physical activity guide-lines, and 12% lower levels of cardiorespiratory fitness, on average. These disparities translate into increased risk of cardiovascular disease, found in previous studies. Con-scripts with lower levels of cardiorespiratory fitness and muscle strength, lower cogni-tive test scores, and higher resting heart rate showed increased risk of developing heart failure at an early age. High resting heart rate was not associated with increased risk for any other of the cardiovascular outcomes that were studied. In summary, the results of this thesis provide new knowledge about how physical activity and cardiorespiratory fitness are potential mediators of social inequalities in cardiovascular disease. In addition, new information regarding factors in early life that influence cardiovascular health in middle age is provided. Keywords: Epidemiology, Physical activity, Fitness, Heart rate, Cognition, Heart failure

Rural/urban redux: Conceptual problems and material effects

[2017-11-20] Title: Rural/urban redux: Conceptual problems and material effects Authors: Dymitrow, Mirek Abstract: Concepts are the basic building blocks of all knowledge, while the strength of the theories that guide any societal project is dependent on the quality those concepts. Contrarily, the utilization of questionable concepts will result in questionable material effects. As two of the oldest geographical concepts still in widespread use, ‘rural’ and ‘urban’ stand in stark contrast to the immense changes encountered by society over the last century, let alone decades. Steady, fast-paced transformations in the environmental, economic and social dimensions have rendered the rural/urban binary a contentious one – a conceptual vestige of sorts, whose blurred and malleable characteristics, immense spatial coverage and aspectual all-inclusiveness have come to form an odd marriage between bygone world views and a globalized 21st-century reality of interconnectedness. The aim of this thesis is to critically evaluate our use of the concepts ‘rural/urban’ in order to help erase the contagion of indifference attached to them in a recalcitrant reality of admissibility. This compilation thesis consists of five theoretically and methodically diverse papers and a summative part inspired by a much wider range of ideas. By combining geographical perspectives with insights from critical theory, cognitive psychology and STS, this eclectic work addresses the phenomenon of rural/urban thinking using a new syntax and a new argumentative narrative with the ambition to change the way that thinking is apprehended and acted upon. With a focus on performativity, constitution and implications of concepts governed by various subject positions and psychosocial factors, this work lays the groundwork for an under-researched dimension of ‘rural/urban’ – that of the human condition – amidst an exceptionally rich conceptual literature on what ‘rural/urban’ “is” or “means”. Three basic conclusions stem from this work. Firstly, anyone talking about ‘rural/urban’ is performing it, and we have no mandate to project ‘rural/urban’ performances onto “people out there” and then evaluate how ‘rural/urban’ is like by examining those people’s actions. Secondly, ‘rural/urban’ are ridden with too many problems with regard to their basic conceptual constitution that their signification is unlikely to converge with what we are trying to explain. Thirdly, since ‘rural/urban’ as spatial concepts are often used with regard to human activities, there is a risk of conflating land with people, and thus forfeiting the core of our approach. Given these three important conceptual problems there is also the likelihood that ‘rural/urban’ may tacitly contribute to the retention of some pressing societal problems. This thesis makes the case for reconfiguring our relationship with familiar conceptions of societal organization. Its principal contribution is to help facilitate decisions on whether ‘rural/urban’ are truly analytically contributory to a specific line of action or whether they serve merely as a cultural ostinato acquired by external, scientifically and societally undesirable, mechanisms.

Clinical and Molecular Studies on Impacted Canines and the Regulatory Functions and Differentiation Potential of the Dental Follicle

[2017-11-20] Title: Clinical and Molecular Studies on Impacted Canines and the Regulatory Functions and Differentiation Potential of the Dental Follicle Authors: Uribe-Trespalacios, Pamela Abstract: Background: Impaction of the permanent maxillary canines, which is a common problem in dentistry, may require surgery and long-term orthodontic treatment. Until now, impaction has mostly been linked to physical obstructions and the direction of movement of the tooth. However, the molecular co-ordination of bone formation and bone resorption necessary for the eruption process, which is suggested to be regulated by the dental follicle, needs to be investigated further. Aims: The overall objectives of this thesis were to determine which clinical factors are related to impacted canines, and to investigate the regulatory functions and differentiation potential of the dental follicle. Patients and methods: The positions of impacted and normally erupting canines (orthopantograms), the skeletal variables (profile radiographs), and dento-alveolar traits (casts) were evaluated as potential predictive factors for impaction using a multivariate data analysis (N=90 patients). The gene expression profiles of boneregulatory markers were determined by RT-qPCR and immunofluorescence staining of human dental follicles. Whole dental follicles (N=11) obtained from impacted canines, with or without signs of root resorption, and from control teeth (normal erupting teeth and mesiodens), together with the apical (N=15) and coronal (N=15) segments (processed independently), were analysed. In vitro osteogenic differentiation of human dental follicle cells (hDFC) was followed by the quantification of gene expression of osteoblast-phenotypic markers and Alizarin Red staining. Quantifications of the molecular permeability of gap junctional intercellular communication and of CX43 expression were performed with the dye parachute technique and flow cytometry, respectively. Next-generation sequencing and bioinformatics processing were used for the identification of differentially regulated genes and pathways involved in the differentiation of hDFC. Results: Clinical variables related to the spatial location of the un-erupted tooth exert the strongest influences on impaction. However, they cannot be attributed to the cause of impaction, and they cannot be used as predictors. The RT-qPCR analyses revealed that the transcript levels for osteoclast-related markers (M-CSF, MCP-1, RANKL) were minimally expressed compared to those for osteoblastic markers (RUNX2, COL-1, OSX, ALP, OCN). No differential patterns of expression were identified between the impacted canines, with or without clinical signs of root resorption, or compared to the follicles from mesiodens or the normally erupting teeth. When the apical and coronal sections were analysed independently, significant differential expression was detected for the RANKL gene in the coronal part of the dental follicles, as compared with their corresponding apical parts. The induced expression levels of RANKL and OPG in cultured hDFC obtained from different patients were also significantly different. CX43 was observed to be highly expressed in the follicular tissues, and its expression was increased when the cells were cultured in osteogenic medium, and even further enhanced when the cells were exposed to silica (Si). We found that multipotent stem cells residing in the dental follicle could be induced to differentiate towards an osteoblastic lineage under favourable in vitro conditions, resulting in regulation of the osteoblastic phenotypic markers (RUNX2, OSX, BMP2, ALP, and OCN) and active deposition of a mineralised matrix. In addition, Si enhanced osteogenic differentiation in combination with osteogenic induction medium, as revealed by increases in the expression of CX43 and gap junction communication activity in the hDFC. Conclusions: The results presented in the thesis reveal that clinical variables are influential, but not determinants, for tooth impaction. The dental follicle in the late pre-eruptive stage mainly expresses osteoblastregulatory markers, whereas the levels of osteoclast-related markers are very low. Significant expression of CX43 and gap junction communication activity were detected, indicating an important role for these factors in the functional processes in the dental follicle. The significant upregulation of RANKL expression in the coronal part of the dental follicles suggests the importance of recruiting and activating osteoclasts, so as to form the eruption path through the alveolar bone. Moreover, the differential expression of induced RANKL in cultured hDFC may explain the diversity of events noted in the clinical setting during tooth eruption. Mesenchymal cells located in the dental follicle provide the optimal precursors, which can be cultured under in vitro conditions and further triggered with Si to differentiate towards an osteoblastic lineage.

”¿Es que crees que estoy loco?” La narración de la conciencia en tres novelas de Ramón Hernández

[2017-11-20] Title: ”¿Es que crees que estoy loco?” La narración de la conciencia en tres novelas de Ramón Hernández Authors: García Nespereira, Sofía Abstract: This dissertation aims to explore how one character’s alleged madness can be called into question. Ramón Hernández’s novels often create an ambiguity about events that befall the main character: have they imagined the plot or did it really happen in the novel’s world? Using three novels by Hernández, this thesis makes the assertion that it is the reader himself who has the last word. On the one hand, the stories show a character that is perceived as mad by her surroundings, but on the other hand, there are textual signals that allow an opposing view. Based on both classical and cognitive narratology, this study examines how the text constructs this ambiguity, and how, through different strategies, the text invites the reader to attribute a consciousness to the characters. The textual analysis shows how the novels encourage a reading in which the reader is asked to adopt the characters’ positions and to feel as they do. This will affect the reader's perception of the assumed madness of the character, which henceforth becomes problematic. Some features that can elicit contradictory responses in relation to the character’s consciousness are homonymy of narrators, which can create confusion as to who (both which narrator; and narrator or character) is speaking; unreliability, where the credibility of first-person narrators can create doubts about events within the narrative the prolific use of the historical present, where the ‘nows’ and ‘thens’ become temporally equalized; or the polysemy of perception verbs, where ‘see’ can also mean ‘remember’, ‘imagine’, ‘hallucinate’. The results of the study suggest that the doubt triggered by the texts can be explained by a narrative clash between two forces. Namely, the novels’ focus on the narration of a character’s experience in the way he/she perceives it, which create closeness between reader and character, and the use of strategies that threaten that closeness.

Language ability in patients with low-grade glioma - detecting signs of subtle dysfunction

[2017-11-17] Title: Language ability in patients with low-grade glioma - detecting signs of subtle dysfunction Authors: Antonsson, Malin Abstract: Background: Low-grade glioma (LGG) is a slow-growing brain tumour often situated in or near areas involved in language and/or cognitive functions. Consequently, there is a risk that patients develop language impairments due to tumour growth or surgical resection. Purposes: The main aim of this thesis was to investigate language ability in patients with LGG in relation to surgical treatment. Language ability was investigated using various sensitive methods such as a test of high-level language. To acquire norms for the test used to investigate high-level language, normative values were obtained in a methodological study (Study I). Methods: In Study I, 100 adults were assessed using a Swedish test of high-level language (BeSS) and a test of verbal working memory. Relationships between these tests and demographic variables were investigated. In Study II, the language ability of 23 newly diagnosed LGG patients was assessed and compared with that of a reference group. The patients were also asked about self-perceived changes in language. In Study III, the language ability of 32 LGG patients was assessed before surgery, early after surgery and at three-months follow-up. The patients’ language ability was compared across these assessment points and with a reference group. Finally, in Study IV, 20 LGG patients wrote a short narrative before and after surgery. The aim was to explore whether the lexical-retrieval difficulties previously seen in oral language could be seen in writing as well. Keystroke logging was used to explore writing fluency and word-level pauses. Here, too, comparisons were made between the assessment points and with a reference group. Results and conclusions: Study I showed that demographic variables had a limited impact on performance on the BeSS whereas verbal working memory influenced performance. Hence verbal working memory was found to influence performance on a test of high-level language. In Study II, the LGG group performed worse than the reference group on tests of lexical retrieval. However, the majority of the newly diagnosed patients with presumed LGG had normal or nearly normal language ability prior to surgery. Only a few patients reported a change in their language ability. In Study III, most patients with a tumour in the left hemisphere manifested language impairment shortly after surgery, but the majority of them had returned to their pre-operative level of performance three months after surgery. Language impairment in patients with a tumour in the right hemisphere was rare at all assessment points. In Study IV, LGG patients had a higher proportion of pauses within words before surgery than the reference group did. After surgery, the patients’ production rate decreased and the proportion of pauses before words increased. Measures of lexical retrieval showed moderate to strong relationships with writing fluency both before and after surgery. The higher frequency of word-level pauses could indicate a lexical deficit. Overall, lexical-retrieval deficits were the most common type of impairment found both before and after surgery in patients with presumed LGG.

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http://sant.gu.se/omuniversitetet/aktuellt/Disputationer/
Utskriftsdatum: 2017-11-25