| 1. |
- Ahlborg, Mikael, 1985-
(author)
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Social capital and inequalities in mental health among young adolescents in Sweden
- 2022
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Doctoral thesis (other academic/artistic)abstract
- The aim of this thesis was to explore social capital and inequalities in mental health among young adolescents in Sweden. This is a compilation thesis comprising four studies. Studies I and II are quantitative studies of crosssectional data from the Swedish Health Behaviour in School-aged Children survey. The aim of Study I was to investigate socioeconomic inequalities in health using both a subjective and an objective measure of socioeconomic status among Swedish adolescents. The findings showed that subjective socioeconomic status robustly and independently predicted mental health problems, poor life satisfaction and poor general health perception. The association between objective socioeconomic status and mental health was weakened, and even reversed, when subjective socioeconomic status was accounted for in regression models. A Latent Profile Analysis was applied in Study II with the aim of identifying distinct profiles of family, school and peer social capital in a nationally representative sample of adolescents and to explore health outcomes in those profiles. The findings showed that five distinct profiles best represented the data for 11 and 15-year olds, while a four-profile model was optimal for 13-year olds. Significant inequalities were identified between profiles when these were examined in terms of mental health problems and life satisfaction. The design of Study III was a qualitative semi-structured interview study. The aim was to explore social capital from the perspective of adolescents in relation to mental health. Adolescents spoke of having access to a safe space, feeling connected to others and predictability as important aspects of social relationships and networks in relation to mental health. The aim of Study IV was to identify and evaluate the design and psychometric properties of instruments for assessing social capital specifically developed and validated for self-reporting among adolescents (10-19 years). The design was a systematic review, in which 20 instruments were identified. The results revealed a lack of instruments that covered both the multidimensionality of social capital and contextual relevance in relation to adolescents. The conclusion from this thesis is that social capital may be useful for identifying vulnerable individuals and for differentiating between the natural imbalance of adolescence and what may lead to serious illness. Longitudinal research and refinement of the operationalization of the concept are, however, needed to enhance the understanding of these findings.
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| 2. |
- Eriksson, Lars, 1966-
(author)
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Att gestalta måltider – mise en place, dukning och servering : En metodstudie i servitörens hantverkskunnande
- 2021
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Doctoral thesis (other academic/artistic)abstract
- I restaurangbranschen har rationaliseringar tvingats fram och kunskap efterfrågas i mindre omfattning. Syftet med avhandlingen är därför att utveckla begrepp och pröva metoder för att återge och förmedla procedurer och göranden i hantverk för att därigenom visa vad som är servitörens yrkeskunskap. Avhandlingen undersöker metoder som fångar hantverkets sinnliga aspekter genom att synliggöra och vetenskapliggöra den dimensionen av ett hantverk. Den ledande frågan är hur servitörens hantverkskunnande för mise en place, dukning och servering kan visualiseras, kommuniceras och förstås?Olika metoder har prövats och forskningen har skett i och genom hantverk med egen restaurangerfarenhet som utgångspunkt. Film som metod har prövats för att vetenskapliggöra betydelsen av hantverkarens sinnliga bedömningar. Metoder från tidsgeografi, som förklarar det materiellas bundenhet till tid och rum, samt från taxonomi för tredimensionell visuell analys, som ger förståelse för gestaltning, har använts.Resultaten visar att hantverkaren oreflekterat tar stöd av sina egna sinnen för att bli effektivare och säkerställa sitt hantverksutförande. Resultaten visar även att de tidsgeografiska begreppen kapacitets-, kopplings- och auktoritetsrestriktioner möjliggör att identifiera och förklara de hinder som servitören tar hänsyn till vid planering och genomförande av en hantverksprocedur. När kunskap om förklaringar länkas samman med kunskap om förståelse, blir det möjligt att beskriva hur gästen i en måltidssituation kan styras och påverkas av estetiken. Genom ett flermetodologiskt tillvägagångssätt har hantverkskunnandet för procedurerna mise en place, dukning och servering artikulerats vetenskapligt i ord och bilder.
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| 3. |
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| 4. |
- Eriksson, Mikael, 1972-
(author)
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Biodegradation of hydrocarbons in soil and water
- 2000
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Doctoral thesis (other academic/artistic)abstract
- Biodegradation of aliphatic and polycyclic aromatichydrocarbons was studied in soil and liquid cultures attemperatures ranging from -5 º C to 20 º C undervarious aerobic or anaerobic, nitrate reducing, conditions. Twocontaminated soils were used in the studies. One contaminatedwith weathered diesel fuel from the Arctic region in northernCanada and one weathered PAH/creosote contaminated soil from anold gaswork site in Stockholm, Sweden. Solid phasemicroextraction (SPME) was used to monitor both degradation andthe analysis of metabolites with gas chromatography and massspectrometry.Aerobic degradation of diesel fuel hydrocarbons was possiblein both uncontaminated potting soil at 20 º C andcontaminated Arctic soil at 7 º C by indigenousmicroorganisms. The Arctic soil contained cold adaptedmicroorganisms and approximately 1500 mg total petroleumhydrocarbons per kg was removed during 60 days of treatment inboth on-site biopiles and in microcosm treatments. Inoculationwith a jet A1 fuel grown cold adapted consortium did notenhance hydrocarbon degradation in any of the treatments.Continuos freezing and thawing, temperature cycling between 7º C and -5 º C every 24 hours did not inhibit theoverall total degradation during 50 days of treatment.Ribosomal intergenic spacer length polymorphism analysis(RIS-LP) showed that the microbial population changed slightlyin the freeze-thaw treated soil compared to soils kept at 7º C.Degradation of polycyclic aromatic hydrocarbons with up tothree aromatic rings was observed at 20 º C under variousnutrient additions and mechanical mixing in weathered creosotecontaminated soil. The mixing showed higher effect ondegradation than the nutrient additions. The compounds in theweathered soil was sorbed to soil particles and unavailable tothe microorganisms. Pure isolates from the PAH-contaminatedcould degrade three ring PAHs within 30 days in liquid culturesat 20 º C and it was shown that addition of salicylic acidstimulated PAH degradation whereas catechol did not. PAHdegrading enrichment cultures were produced from various soils,and it was shown that PAHs with up to four aromatic rings couldbe degraded at low temperature and under nitrate reducingconditions was accumulated in most systems during PAHdegradation. 9-Fluorenone accumulated to higher concentrationsin uncontaminated soils than in soil exposed to PAHs.A novel type of growth on pyrene crystals in liquid cultureswas also studied. The obtained biofilm was extracted for DNA,and cloning and partial 16S-rDNA analysis showed that the threemost abundant clones matchedPolaromonassp.,Sphingomonassp. andAlcaligenessp.Keywords:Solid Phase Microextraction, SPME,biodegradation, bioremediation, bioavailability, monitoring,Volatile Organic Compounds (VOC), Screening, headspacesampling, polycyclic aromatic hydrocarbons, PAHs, aliphatichydrocarbons, total petroleum hydrocarbons, TPH, biofilmproduction,Pseudomonassp. 9-fluorenone.
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| 5. |
- Eriksson, Mikael, 1967
(author)
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Biomaterial Components Prepared by Titanium Powder Technology
- 2004
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Doctoral thesis (other academic/artistic)abstract
- The main objectives of this work were twofold: First, to determine if a pressed-powder method could be used to fabricate titanium dental copings, and to line out what problems or benefits this new method would have. Second, to test if high velocity compaction of titanium powder could be used to form biomaterial components such as copings or dental implants. The dental components were prepared from pure titanium powder, with irregular grains (hydrided-dehydrided) beneficial for pressing. The powder was pressed against a mandrel (tooth preparation die) using cold isostatic pressing. The tooth preparation dies and the copings were fabricated using a milling machine working with scanned dental shapes, digitally enlarged to compensate for the sintering shrinkage. The materials were sintered using vacuum-furnaces and investigated with several techniques. A deformation problem on the copings was investigated. High velocity compaction was studied as an alternative method to prepare dental copings and simulations of this process was initiated. Hydroxyapatite grains of a narrow size-range was mixed with a titanium powder and formed with high velocity compaction to form a composite material. A method to manufacture up to 99% dense and ductile titanium copings was developed. The sintering shrinkage could be compensated for. The main cause of the deformation was found to be a deformation effect on the tooth preparation dies. Other possible deformation causes were small. Sintered copings of various shapes could be prepared. Very high green densities were obtained by using high velocity compaction and a method using elastic forms to prepare copings was developed. Initial simulation results were reached to better understand the compaction behaviour and to find the best form geometry. A 99% dense titanium-hydroxyapatite biomaterial composite was prepared without detectable destructive reactions. The method worked to fabricate titanium dental copings of various shapes into an approved fit. The mandrel material turned out to be the most important factor to consider for avoiding deformation. Density gradients in pressed titanium were found but were small. Dental copings could also be prepared with high velocity compaction. A dense composite of titanium and hydroxyapatite could be prepared and composite implant components were manufactured.
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| 6. |
- Eriksson, Mikael, 1951-
(author)
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Epidemiological studies on multiple myeloma
- 1992
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Doctoral thesis (other academic/artistic)abstract
- Multiple myeloma is a painful and uncurable malignant disease with an increasing incidence and mortality in several countries, e.g., Sweden. Some factors are suspected to be of aetiological significance, such as ionising radiation and chronic antigenic stimulation in certain inflammatory diseases. A familial factor has also been indicated. Furthermore, some studies have demonstrated farming as an occupation entailing an increased risk for the disease.The aim of this investigation was to further elucidate the impact of different aetiological factors in relation to multiple myeloma. The knowledge of aetiology is always a prerequisite for prevention.A case-control study on multiple myeloma was performed in a high-inddence area, the northern part of Sweden. One part of this study dealt with occupations and different exposures. The results supported farming as being an occupation with an increased risk. Within farming two kinds of pesticides, phenoxyacetic adds and DDT, and contact with certain domestic animals, i.e., cattle, horses and goats, were assodated with multiple myeloma.Farming as a risk factor was also confirmed by a register-based linkage study using the Swedish Cancer Environment Register. In this study a time trend was indicated, with increasing standardized inddence ratios over the different time periods studied.Another part of the case-control study showed that rheumatoid arthritis entailed an increased risk for multiple myeloma, a finding earlier suggested from register-based linkage studies, but not from any çase-control study.A third part of the case-control study indicated an increased risk for multiple myeloma if any first-degree relative had a history of haematological malignancy, or other malignant tumour, espedally prostatic cancer, brain tumour, and renal cancer.A case study encompassing 942 patients with haematological malignandes in the county of Jämtland, Sweden, during a 22-year period showed that about 5% of the patients had at least one relative who also suffered from such a disease. An espedally strong familial occurrence was found in the group of chronic lymphoprohferative diseases, including multiple myeloma.
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| 7. |
- Eriksson, Mikael
(author)
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Friction and contact phenomena of disc brakes related to squeal
- 2000
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Doctoral thesis (other academic/artistic)abstract
- Brake squeal is a sound with a main frequency between 1 and 20 kHz, generated by an oscillation of the components of the brake system. The energy driving the oscillation is supplied by the friction between the disc and the pads. Obviously, the friction characteristics have a major influence on the propensity for squeal generation in any given brake assembly.In the present thesis, friction phenomena and squeal generation of a brake system have been studied and correlated to the surface structure of the brake pads. Furthermore, the processes for the formation and disintegration of contact plateaus, occuring on the pad surface, have been investigated in detail.It is found that brake squeal can not be generated if the coefficient of friction isbelow a critical level, depending on design and friction characteristics of the brakesystem. Above the critical level, squeal generation is apparently stochastic, and theprobability for squeal dependent on the set of conditions. It is concluded that theseemingly stochastic behaviour of squeal generation only can be explained by thesubtle surface phenomena affecting the friction characteristics.It is further shown that contact plateaus form on the surface of organic brake pads. These are constituted by the wear resistant structural components of the pad, and wear debris compacting against the leading edge of the structural components. The expressions primary and secondary plateaus are introduced for the structural components and the compacted debris, respectively. The work has clarified some of the surface interaction phenomena responsible for the friction behaviour of organic brake pads.
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| 8. |
- Eriksson, Mikael, 1976-
(author)
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Modelling and Experimental Verification of Direct Drive Wave Energy Conversion : Buoy-Generator Dynamics
- 2007
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Doctoral thesis (other academic/artistic)abstract
- This thesis is focused on development of models and modelling of a wave energy converter in operation. Through the thesis linear potential wave theory has been used to describe the wave-buoy interaction. The differences lie in the generator models, in the simplest model the generator is a mechanical damper characterized by a damping factor. In the most advanced generator model the magnetic fields is calculated the by a FE-method, which gives detailed description of the electric properties and the effect it has on the buoy dynamics. Moreover, an equivalent circuit description of the generator has been tested. It has the same accuracy as the field based model but with a strongly enhanced CPU time. All models are verified against full scale experiments. The models are intended to be used for design of the next generation wave energy converters. Further, the developed models have also been used to study what effect buoy geometry and generator damping have on the ability to energy absorption. In the spring 2006 a full scale wave energy converter was installed at the west coast of Sweden. It was in operation and collected data during three months. During that period the load resistance was varied in order to study the effect on the energy absorption. These collected data was then used in the verification of the developed models. In the year 2002 a wave energy project started at Uppsala University; this work is a part of that larger project which intendeds to develop a viable wave energy conversion concept.
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| 9. |
- Eriksson, Mikael, 1972-
(author)
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Procurement of Complex Technical Systems : Strategies for Successful Projects
- 2005
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Doctoral thesis (other academic/artistic)abstract
- When facing a procurement of a complex technical system, many questions are to be asked. The main question is how the best and most suitable systems are obtained, at the right cost. In order to answer that question numerous aspects must be considered and investigated. Even after having conducted careful analysis the question will most certainly never be entirely answered. In the early stages of procurement projects it is important that time is allocated for evaluation and decision-making concerning what truly is needed and most important on the management strategy to use. Procurement projects often misses someone that have a totality perspective, the projects are often extended in time, the experience and competence of the involved actors are often not properly used in the projects and it is impossible to write clear-cut contracts between the involved actors. These incongruities create need for focused and applicable procurement strategies. It is in the beginning of the procurement process that these decisions concerning which procurement strategies to be used in the project have to be made. The strategy decisions should primarily be based on the available competence of the already involved actors, and secondly on what competencies available at possible actors to involve. The competencies needed in the different phases of the procurement project can be predicted fairly accurately. The risks and responsibilities should be distributed among the involved actors depending on their accessible competence and resources. Focus should be on the capabilities of the involved actors instead of on the cost. Decisions made in the initial phases must also allow as much flexibility as possible for the later phases to come. In the research, case studies on procurement projects have been conducted. In the case studies data have been gathered and case study analyses have formed a comprehensive view of procurement projects. The research in this thesis offers insight on the impact of procurement strategy on allocation of responsibilities and risks in procurement projects and the importance of a well formulated procurement strategy is stressed. The procurement strategy is important when to efficiently utilize available competencies and resources. Also, the importance of how to formulate requirements that enable the best possible contribution to the project of all the available and involved actors has been examined. How the requirements are formulated and communicated determine to very large extend how the project should be organised, both by the client and the supplier. This thesis gives guidelines on the organisation of procurement projects for complex technical systems. It further discusses the formulation of procurement strategies depending on the involved actors’ competencies. A framework for procurement of complex technical systems is also presented.
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| 10. |
- Eriksson, Mikael
(author)
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Risk assessment and prevention of breast cancer
- 2020
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Doctoral thesis (other academic/artistic)abstract
- One woman in eight develops breast cancer during her lifetime in the Western world. Measures are warranted to reduce mortality and to prevent breast cancer. Mammography screening reduces mortality by early detection. However, approximately one fourth of the women who develop breast cancer are diagnosed within two years after a negative screen. There is a need to identify the short-term risk of these women to better guide clinical followup. Another drawback of mammography screening is that it focuses on early detection only and not on breast cancer prevention. Today, it is known that women attending screening can be stratified into high and low risk of breast cancer. Women at high risk could be offered preventive measures such as low-dose tamoxifen to reduce breast cancer incidence. Women at low risk do not benefit from screening and could be offered less frequent screening. In study I, we developed and validated the mammographic density measurement tool STRATUS to enable mammogram resources at hospitals for large scale epidemiological studies on risk, masking, and therapy response in relation to breast cancer. STRATUS showed similar measurement results on different types of mammograms at different hospitals. Longitudinal studies on mammographic density could also be analysed more accurate with less nonbiological variability. In study II, we developed and validated a short-term risk model based on mammographic features (mammographic density, microcalcifications, masses) and differences in occurrences of mammographic features between left and right breasts. The model could optionally be expanded with lifestyle factors, family history of breast cancer, and genetic determinants. Based on the results, we showed that among women with a negative mammography screen, the short-term risk tool was suitable to identify women that developed breast cancer before or at next screening. We also showed that traditional long-term risk models were less suitable to identify the women who in a short time-period after risk assessment were diagnosed with breast cancer. In study III, we performed a phase II trial to identify the lowest dose of tamoxifen that could reduce mammographic density, an early marker for reduced breast cancer risk, to the same extent as standard 20 mg dose but cause less side-effects. We identified 2.5 mg tamoxifen to be non-inferior for reducing mammographic density. The women who used 2.5 mg tamoxifen also reported approximately 50% less severe vasomotor side-effects. In study IV, we investigated the use of low-dose tamoxifen for an additional clinical use case to increase screening sensitivity through its effect on reducing mammographic density. It was shown that 24% of the interval cancers have a potential to be detected at prior screen. In conclusion, tools were developed for assessing mammographic density and breast cancer risk. In addition, two low-dose tamoxifen concepts were developed for breast cancer prevention and improved screening sensitivity. Clinical prospective validation is further needed for the risk assessment tool and the low-dose tamoxifen concepts for the use in breast cancer prevention and for reducing breast cancer mortality.
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