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- ARNELL, MAGNUS
(författare)
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Performance Assessment of Wastewater Treatment Plants : Multi-Objective Analysis Using Plant-Wide Models
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As the knowledge about anthropogenic impacts of climate change has grown, the awareness of the contributions from treatment of wastewater has widened the scope for wastewater treatment plants (WWTPs). Not only shall ever stricter effluent constraints be met, but also energy efficiency be increased, greenhouse gases mitigated and resources recovered. All under a constant pressure on costs. The main objective of this research has been to develop a plant-wide modelling tool to evaluate the performance of operational strategies for multiple objectives at the plant and for off-site environmental impact. The plant-wide model platform Benchmark Simulation Model no. 2 (BSM2) has been modified to improve the evaluation of energy efficiency and include greenhouse gas emissions. Furthermore, the plant-wide process model has been coupled to a life cycle analysis (LCA) model for evaluation of global environmental impact. For energy evaluation, a dynamic aeration system model has been adapted and implemented. The aeration model includes oxygen transfer efficiency, dynamic pressure in the distribution system and non-linear behaviour of blower performance. To allow for modelling of energy recovery via anaerobic co-digestion the digestion model of BSM2 was updated with a flexible co-digestion model allowing for dynamic co-substrate feeds. A feasible procedure for substrate characterisation was proposed. Emissions of the greenhouse gases CO2, CH4 and N2O were considered. The bioprocess model in BSM2 was updated with two-step nitrification, four-step denitrification and nitrifier denitrification to capture N2O production. Fugitive emissions of the three gases were included from digestion, cogeneration and sludge storage. The models were tested in case studies for the three areas of development: aeration, co-digestion and greenhouse gas production. They failed to reject the hypothesis that dynamic process models are required to assess the highly variable operations of wastewater treatment plants. All parts were combined in a case study of the Käppala WWTP in Lidingö, Sweden, for comparison of operational strategies and evaluation of stricter effluent constraints. The averaged model outputs were exported to an LCA model to include off-site production of input goods and impact of discharged residues and wastes. The results reveal trade-offs between water quality, energy efficiency, greenhouse gas emissions and abiotic depletion of elemental and fossil resources. The developed tool is generally applicable for WWTPs and the simulation results from this type of combined models create a good basis for decision support.
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| 2. |
- Hörer, Tal, 1971-
(författare)
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Early detection of major surgical postoperative complications evaluated by microdialysis
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Major abdominal surgery may be followed by postoperative complications, especially in the elderly and patients with co morbidities as diabetes mellitus and obesity. Some of the most feared complications as anastomotic leakage, abdominal infections, abdominal compartment syndrome (ACS) and intestinal ischemia can lead to sepsis, systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) with high morbidity and mortality. This thesis evaluates intraperitoneal microdialysis (IPM) as a method for early detection of surgical complications. IPM measures extracellular metabolites as lactate, pyruvate, glycerol and glucose. The lactate/pyruvate (l/p) ratio describes the current relationship between aerobic and anaerobic metabolism. Glycerol is a degradation product of lipolysis from fat and a part of the cell membrane and released when cell injury occurs. In Paper I, evaluation of IPM in patients with and without diabetes mellitus and obesity during 48 hours after abdominal surgery did not show any difference in l/p ratio and glycerol levels compared to a control group. Paper II investigated the first two days after abdominal surgery in patients with major complications using IPM. L/p ratio was higher and glycerol was lower. Paper III used IPM in the immediate postoperative period in patients after endovascular repair for ruptured abdominal aortic aneurysm (rEVAR). Patients who required decompression due to intraabdominal hypertension (IAH) with organ failure had higher l/p ratio and glycerol. Paper IV investigated the effects of Aortic Balloon Occlusion (ABO) and Superior Mesenteric Artery (SMA) occlusion for one hour followed by three hours reperfusion in an animal model. ABO had a pronounced effect on the hemodynamic state. I.p l/p ratio increased during ischemia and decreased on reperfusion while glycerol increased on reperfusion and the effect was less pronounced in the SMA group. In conclusion, IPM monitoring of l/p ratio and glycerol indicates serious postoperative complications at an early stage. The l/p ratio increases or is continuously high while glycerol seems to have a more complex pattern. Diabetes and obesity do not influence the results.
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| 3. |
- Piuva, Katarina, 1954-
(författare)
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Normalitetens gränser : En studie om 1900-talets mentalhygieniska diskurser
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The comprehensive aim of the dissertation is to examine how ideas about mental hygiene have been elaborated and debated within the context of Swedish welfare. The dissertation is a compilation of four articles where issues of mental hygiene are examined in detail through an analysis of texts. In addition, a theoretical and methodological framework and a discussion of the concepts of mental health and normality are asserted to the dissertation. The subjects of research are (1) the launching of the movement in USA in the early twentieth, and the autobiographical narrative "A Mind That Found Itself" (Beers 1908), (2) the conception and the evolution of the movement in Sweden, (3) the psychosocial training within the education of social workers between the years 1939 –1989, and (4) the debate about the Mental health Campaign in 1969. The issues of mental hygiene and mental health discussed in the articles are elaborated in relation to the academic disciplines of Sociology of Health and Illness and the History of Public Health. The theoretical approach of these disciplines proceeds from a post-structural and social constructivist perspective of knowledge and language, a perspective also used in the interpretation of the textual materials. The section where the research methods are presented, consists of a description of how the textual materials have been selected and treated in relation to the theoretical and methodological standpoints.The outcome of the investigation of the autobiographical book"A Mind That Found Itself" (Beers 1908) in relation to the launching of the movement in the USA, is that the monomyth-character of the story supported an image of victory and hope, important for the movements aims to improve the reputation of psychiatry. Concerning the launching of the mental hygiene movement in Sweden two important conditions stands out as the course behind the rather hesitant start: the dominant position of custodial care and the antagonistic attitude towards psychoanalytical theories. The study of the psychosocial training of social workers showed how the skills of the clinical gaze were taught to the students by the technique of case-writing. The study of the Mental Health campaign in 1969 showed important divergences concerning the opinions of normality. Since the individual anatomy in the welfare system in Sweden is organised through the individuals position within the labour market, the issues of mental health and allied opinions of normality also contained the risks of exclusion. In conclusion, a comprehensive reflection concerning the results of the studies, is that the concept of mental hygiene, due to the mix of psychiatric and social knowledge, mediated shifting ideas about normality.
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| 4. |
- Stenbäck, Anders, 1971-
(författare)
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Studies of Experimental Bacterial Translocation
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the main obstacles to maintaining patients with short bowel syndrome on parenteral nutrition, or successfully transplanting these patients with a small bowel graft, is the many severe infections that occur. Evidence is accumulating that translocating bacteria from the patient’s bowel causes a significant part of these infections. In this thesis bacterial translocation is studied in a Thiry-Vella loop of defunctionalised small bowel in the rat. Bacterial translocation to the mesenteric lymph nodes (MLNs) occurs in almost 100% of the rats after three days. No systemic spread of bacteria is observed unless there is additional immunosupression with depletion of Kupffer cells in the liver. However, blocking the function of α/β T cells does not increase the translocation. Removal of MLNs does not either aggravate bacterial translocation in the Thiry-Vella loop model. Conversely, after small bowel transplantation translocating bacteria spread systemically if the MLNs are removed. The Thiry-Vella loop should also be a suitable model for the testing of potentially translocation-inhibiting substances. Reinforcement of the intestinal barrier with glutamine or phosphatidylcholine proved insufficient in decreasing bacterial translocation. Even selective bowel decontamination with tobramycin failed to abolish bacterial translocation. Thus, it seems that the driving force for translocation in this model is strong regardless of the relatively small trauma of intestinal defunctionalisation. Flow cytometric studies of the immune cells in the spleen MLNs showed a decrease in MHC class II positive T cells in the MLNs of the Thiry-Vella loop. Concurrently the number of macrophages increased with time as observed by immunohistochemistry. The fraction of MHC class II negative macrophages increased in the spleens of rats treated with glutamine. In conclusion, the Thiry-Vella loop model offers possibilities of immunological as well as mechanistic studies on bacterial translocation from small intestine.
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