| 1. |
- Aripaka, Karthik, 1986-
(författare)
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Studies on the biological functions of interaction between components in Wnt, TGF-β and HIF pathways for cancer progression
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cancer is a disease that involves aggressive changes in the genome and aberrant signals between the living cells. Signalling pathways such as TGF-β (Transforming growth factor-β), Wnt, EGF (epidermal growth factor) and HIF (Hypoxia-inducible factor) evolved to regulate growth and development in mammals. These factors are also implicated for tumorigenesis due to failure or aberrant expression of components in these pathways. Cancer progression is a multistep process, and these steps reflect genetic alterations driving the progressive transformation of healthy human cells into highly malignant derivatives. Many types of cancers are diagnosed in the human population, such as head & neck, cervical, brain, liver, colon, prostate, uterine, breast, and renal cell cancer.Prostate cancer is the second most common cancer and one of the foremost leading cancer-related deaths in men in the world. Aberrant Wnt3a signals promote cancer progression through the accumulation of β-Catenin. In the first paper, we have elucidated intriguing functions for Tumour necrosis factor receptor-associated factor 6 (TRAF6) as a coregulatory factor for the expression of Wnt-target genes which was confirmed in vivo by using CRISPR/Cas9 genomic editing, in zebrafish. Our data suggest that Wnt3a promotes TRAF6 interaction with Wnt components, and TRAF6 is required for gene expression of β-Catenin as well as for the Wnt-ligand co-receptor LRP5. From the in vivo studies, we elucidated positive regulation of TRAF6, which is crucial for survival and development of zebrafish. This study identifies TRAF6 as an evolutionary conserved co-regulatory protein in the Wnt pathway that also promotes the progression of prostate and colorectal cancer due to its positive effects on Wnt3a signalling.Hypoxia is a condition due to O2 deprivation, and Hypoxia-inducible factors (HIF) transcription factors are responsible for the maintenance of oxygen homeostasis in living cells. Irregularities in these HIF transcription factors trigger pathological cellular responses for initiation and progression of malignant cancers. Renal cell carcinoma, malignant cancer arising in renal parenchyma and renal pelvis and, hypoxia plays a vital role in its progression. In the second paper, we have investigated the clinicopathological relevance of several hypoxic and TGF-β component proteins such as HIF-1α/2α/3α, TGF-β type 1 receptor (ALK5-FL) and the intracellular domain of ALK5 (ALK5-ICD), SNAI1 and PAI-1 with patient survival in clear cell renal cell carcinoma (ccRCC). We showed that HIF-2α associated with low cancer-specific survival. HIF-2α and SNAI1 positively correlated with ALK5-ICD, pSMAD2/3, PAI-1 and SNAI1 with HIF-2α; HIF-1α positively correlated with pSMAD2/3. Further, under normoxic conditions, our data suggest that ALK5 interacts with HIF-1α and HIF-2α, and promotes their expression and target genes such as GLUT1 and CA9, in a VHL dependent manner through its kinase activity. These findings shed light on the critical aspect of cross-talk between TGF-β signalling and hypoxia pathway, and also the novel finding of an interaction between ALK5 and HIF-α might provide a more in-depth understanding of mechanisms behind tumour progressionIn the third paper, an ongoing study, we investigated the role of HIF-3α in the progression of Renal cell carcinoma and its association with the components of TGF-β and HIF pathways. We have observed increased levels of HIF-3α in ccRCC and pRCC (papillary renal cell carcinoma) which are associated with advanced tumour stage, metastasis and larger tumours. Also, we found HIF-3α show a significant positive association with pro-invasive gene SNAI1, which is a crucial regulator of epithelial to mesenchymal transition. TRAF6 an E3 ligase known to be a prognostic marker in RCC and we observed HIF-3α associates with TRAF6.
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| 2. |
- Lilja, Johan, 1977-
(författare)
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[18F]Flutemetamol PET image processing, visualization and quantification targeting clinical routine
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Alzheimer’s disease (AD) is the leading cause of dementia and is alone responsible for 60-70% of all cases of dementia. Though sharing clinical symptoms with other types of dementia, the hallmarks of AD are the abundance of extracellular depositions of β-amyloid (Aβ) plaques, intracellular neurofibrillary tangles of hyper phosphorylated tau proteins and synaptic depletion. The onset of the physiological hallmarks may precede clinical symptoms with a decade or more, and once clinical symptoms occur it may be difficult to separate AD from other types of dementia based on clinical symptoms alone. Since the introduction of radiolabeled Aβ tracer substances for positron emission tomography (PET) imaging it is possible to image the Aβ depositions in-vivo, strengthening the confidence in the diagnosis. Because the accumulation of Aβ may occur years before the first clinical symptoms are shown and even reach a plateau, Aβ PET imaging may not be feasible for disease progress monitoring. However, a negative scan may be used to rule out AD as the underlying cause to the clinical symptoms. It may also be used as a predictor to evaluate the risk of developing AD in patients with mild cognitive impairment (MCI) as well as monitoring potential effects of anti-amyloid drugs.Though currently validated for dichotomous visual assessment only, there is evidence to suggest that quantification of Aβ PET images may reduce inter-reader variability and aid in the monitoring of treatment effects from anti-amyloid drugs.The aim of this thesis was to refine existing methods and develop new ones for processing, quantification and visualization of Aβ PET images to aid in the diagnosis and monitoring of potential treatment of AD in clinical routine. Specifically, the focus for this thesis has been to find a way to fully automatically quantify and visualize a patient’s Aβ PET image in such way that it is presented in a uniform way and show how it relates to what is considered normal. To achieve the aim of the thesis registration algorithms, providing the means to register a patient’s Aβ PET image to a common stereotactic space avoiding the bias of different uptake patterns for Aβ- and Aβ+ images, a suitable region atlas and a 3-dimensional stereotactic surface projections (3D SSP) method, capable of projecting cortical activity onto the surface of a 3D model of the brain without sampling white matter, were developed and evaluated.The material for development and testing comprised 724 individual amyloid PET brain images from six distinct cohorts, ranging from healthy volunteers to definite AD. The new methods could be implemented in a fully automated workflow and were found to be highly accurate, when tested by comparisons to Standards of Truth, such as defining regional uptake from PET images co-registered to magnetic resonance images, post-mortem histopathology and the visual consensus diagnosis of imaging experts.
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| 3. |
- Larsson, Jenny, 1990-
(författare)
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Population-based studies of higher-level gait disorders and hydrocephalus : focused on brain ventricular morphometry and patient outcomes following shunt surgery
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: To study gait is of great importance for the health of the aging population. Higher-level gait disorders (HLGD) are characterized by a slow, symmetrical, unsteady gait. Its cause is most often unknown. HLGD in combination with ventriculomegaly (i.e., large brain ventricles) is obligatory for the diagnosis of Idiopathic Normal pressure hydrocephalus (INPH), a syndrome that is sometimes treatable with insertion of a CSF shunt. It is therefore important to investigate the prevalence of HLGD in the population and brain morphometry in individuals with HLGD. Further, self-perceived confidence in gait and balance among patients with HLGD and INPH is unknown and important to study as slow gait velocity is associated with falls, injuries, and death. CSF shunts in INPH are associated with adverse events and little is known about epilepsy after surgery or minor and moderate adverse events such as headache and abdominal pain.Objective: In the older population investigate the prevalence of HLGD, and its association to ventriculomegaly. To investigate quality of life (QoL), depressive symptoms, and balance confidence in an HLGD population. In patients shunted for INPH, assess falls, fear of falling, balance confidence and prevalence of the possible adverse events headache, epilepsy, and abdominal pain after shunt surgery. Methods: Two population-based case-controlled cohorts were studied. In the first study, the "Ventriculomegaly and gait disturbance in the senior population in the region of Västerbotten" (VESPR) study, individuals (65-84 years) were recruited through a questionnaire (n=6467 dispatched). The final population consisted of 798 cases with gait disorders and 249 controls without gait disorders, age- and sex-matched to individuals with HLGD. All had been examined by a physician and were categorized: 1. "HLGD"; 2. "neurological gait disorder"; 3. "non-neurological gait disorder" or; 4. "no gait disorder". Participants were assessed with: the Swedish modification of the Falls-Efficacy Scale (FES(S)), the Modified Gait-Efficacy Scale (mGES), the Euro Quality of Life 5-Dimension 5-Level (EQ5D5L) instrument (EQ5D5L index and Euro Quality of life visual analogue scale (EQ VAS)) and the Geriatric depression scale 15 (GDS-15). Cases and controls had an MRI of the brain and ventricular size was measured. The second study, the "Comorbidities and vascular risk factors associated with idiopathic normal pressure hydrocephalus" (INPH-CRasH) study, consisted of 176 shunted INPH patients and 368 age- and sex-matched controls. Mean age was 74 years in INPH and 73 in controls. All had a visit to a healthcare facility. Information regarding adverse events, falls and fear of falling were gathered through a questionnaire. Additional information on diagnoses and prescribed drugs were obtained from the Swedish national patient- and drug registries. Data was compared between the groups, and before- and after surgery for INPH. Results: In the VESPR study, 87 individuals were categorized as HLGD, corresponding to a prevalence of 5.8% (95% confidence interval (CI) 4.6-7.0) in the older population. A definite cause was found in 13% (n=11) of individuals with HLGD, but ventriculomegaly was present in 63% (n=46/73, controls: 38%, n=70/184; OR 2.8 95% CI 1.6-4.9, p<0.001). HLGD had more depressive symptoms and lower quality of life (QoL), compared with individuals without gait disorder (GDS-15: 3.9±3.4 vs. 2.5±2.8, p=0.004; EQ VAS: 63±17 vs. 71±18; p<0.001; EQ5D5L index: 0.671±0.188 vs. 0.840±0.126, p<0.001). HLGD had low confidence in gait and to avoid falls compared to those without gait disorder (mGES: 60±22 vs. 74±21; p<0.001; FES(S): 93±32 vs. 111±25 p<0.001). The INPH-CRasH study revealed that patients with INPH feared falling more often (3.3±1.1) and had lower balance confidence (78±40) than controls (fear of falling: 1.6±0.9, balance confidence: 126±14; p<0.001 in both comparisons). After surgery, the proportions were reduced in INPH (p<0.001). More INPH than controls were fallers (before surgery: 67% vs. 11% OR 15.48 95% CI 9.85-24.32; after surgery: 35% vs 11% OR 4.15 95% CI 2.65-6.50, p<0.001). The proportion was reduced after surgery (p<0.001). In shunted INPH, epilepsy, antiepileptic drug (AED) treatment and headache was more common than in controls (epilepsy: 4.5% vs. 1.1% OR 4.3, 95% CI 1.3-14.6, p=0.023; AED treatment: 14.8% vs. 7.3% OR 0.5 95% CI 0.3-0.8, p=0.010; headache: 36.1% vs 11.6% OR 0.2 95% CI 0.2-0.4, p<0.001). Forty percent INPH (n=70) had abdominal pain after surgery. Conclusions: HLGD was common in the general older population and associated to ventriculomegaly. HLGD was also associated with low quality of life and depressive symptoms. Both individuals with HLGD and patients with INPH had low confidence in their balance but it was less common after surgery for INPH. However, patients shunted for INPH still had more problems with low balance confidence, falls, and fear of falling than controls. After shunt surgery for INPH, a significant portion of patients developed epilepsy, headache, and abdominal pain. The findings motivate investigations of causal relationships between HLGD and ventriculomegaly and if treatment options exist for HLGD. The observed adverse events in patients shunted for INPH should be considered in pre- and postoperative evaluations of shunt surgery, and in the development of new techniques for shunt placement. Additional interventions directed towards low balance confidence, falls and fear of falling should be considered for patients with INPH, and for individuals with HLGD.
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| 4. |
- Xu, Wenqian, 1992-
(författare)
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Ageism in the Media : Online Representations of Older People
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ageism is a social problem that has harmful effects on the wellbeing of older people and needs to be tackled. It is pervasive and evident in the media (e.g., films, television, print and social media). Despite the fact that non-individual actors have adopted social media on a large scale in contemporary society, the social media representation of older people generated by those actors has remained insufficiently studied. This thesis aims to increase our knowledge of social media representations of older people and improve our understanding of ageism in the media. The knowledge obtained from this research can be used to inform policy and practice in terms of mitigating ageism in the media.This thesis consists of four articles, which examine social media representations of older people generated by local authorities and media companies, with a particular focus on exploring how older people are represented in social media and how social media content about older people is produced. Articles 1, 3 and 4 present empirical analyses of social media texts about older people generated by Swedish local authorities and Chinese media companies, serving to identify the representations that may lead to ageism. Article 2 offers an empirical analysis of the production process for social media photos of older people within local authorities, serving to explore the ways in which stereotypical third-age representations are generated. This thesis employs the methods of content analysis and thematic analysis to examine representations of older people on various social media platforms (i.e., local-authority-managed Facebook pages, Tencent Video as a video streaming platform and Sina Weibo as a microblogging platform). It also employs the method of thematic analysis to analyse interview transcripts concerning the production of social media photos of older people within local authorities.The results of the thesis reveal the complexity and nuances in the representation process and the meanings generated by those representations of older people on social media. More specifically, the thesis illuminates three ways in which the social media representations of older people lead to ageism: (1) the stereotyping of older people through signifying practice; (2) the generation and negotiation of the meanings surrounding older people among social actors with different power relations; and (3) the use of formal and informal rules within social media in the representation activities of mediatized institutions. A synthesis of the findings from the four empirical articles indicates a process of establishing the stereotypical third-age representation as a convention for social media, which can be seen as institutional ageism. The synthesis also indicates that this stereotypical third-age representation appears to be prominent in different contexts and across the various types of social media under examination. In this regard, it is necessary to promote knowledge and raise awareness about the risks associated with such representations of older people in the media. This thesis deepens our understanding of ageism in the media and generates evidence-based policy recommendations for media producers to inspire more thoughtful and reflexive media representations of older people and later life.
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| 5. |
- Borgenvik, Anna, 1987-
(författare)
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MYC-driven Medulloblastoma : New Targeted Therapies and Mechanisms of Recurrence
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Medulloblastoma is the most common malignant brain tumor of childhood. It arises in the posterior fossa but presents with distinct histological and molecular features. Hence, medulloblastoma is divided into four molecular subgroups, WNT, SHH, Group 3, and Group 4. The overall 5-year survival is ~70% across subgroups but varies with high- and low-risk disease. Standard treatment of medulloblastoma consists of maximal safe tumor resection, radiotherapy, and adjuvant chemotherapy. Despite the rather high success rate of treatment for many patients it also comes with severe long-term debilitating side effects. MYC proteins are master regulators of gene expression often deregulated in cancer. MYC family members MYC and MYCN share similar roles and are found overexpressed or amplified in most medulloblastoma subgroups and correlate with a poor prognosis. Medulloblastoma dissemination and recurrence patterns differ between subgroups but are always associated with a poor prognosis. Recurrent medulloblastoma is not yet curable and will lead to death. In this thesis, we present the first transgenic mouse model of medulloblastoma recurrence and highlight the role of the transcription factor SOX9 in MYC-driven relapse mechanisms. By studying this recurrence model and matched primary-recurrent patient samples we propose a mechanism in which treatment-refractory and quiescent SOX9-positive cells in Group 3 medulloblastoma are necessary for tumor relapse, and how the recurrent tumors can be specifically treated with MGMT inhibitors and doxorubicin.In addition, we address efficient treatment options of primary MYC-driven medulloblastoma where BET bromodomain inhibition (JQ1) in combination with CDK2 inhibition (milciclib) of human Group 3 medulloblastoma will lead to apoptosis and prolonged survival of xenografted mice. This is explained by a dual hit on MYC transcriptional output and MYC protein stability exerted by JQ1 and milciclib respectively. Finally, in a different novel transgenic model of MYC-driven medulloblastoma, we show how temporal Cdk2 knock-out has no effect on MYC protein stability but slows down proliferation and prolongs survival of allografted mice. The need for better treatments and increased understanding of recurrent medulloblastoma is huge. To that end, this thesis focuses on and addresses novel treatments, the role of the cell cycle protein CDK2 as well as relapse mechanisms depending on dormant SOX9-positive cells in highly aggressive MYC-driven medulloblastoma.
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| 6. |
- Frändén, Märit, 1973-
(författare)
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"Att blotta vem jag är" : Släktnamnsskick och släktnamnsbyten hos samer i Sverige 1920–2009
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to describe surname patterns and changes of surname among the Sami of Sweden. It presents the results of three studies. The first is a survey of the present-day stock of surnames (family names) among the Sami community, based on the 2005 electoral register for the Swedish Sami Parliament. It investigates the proportions of names deriving from different languages, and the commonest names in each group. The same study was carried out for different areas, showing that the northernmost parts of Sweden have a Sami name stock significantly different from that of the majority population. Further south, the stock of names is less marked, but no area is without Sami elements.The second study, based on archival material, concerns changes of name by Swedish Sami to newly formed surnames, over the period 1920–2004. It examines not only the names adopted, but also the ones replaced; how the name stock has been affected by different patterns of name change; and, as far as possible, who the name changers were. The study shows that, for a long time, names derived from Sami and Finnish were replaced with names formed from Swedish. This may be largely because of the stigma once attached to Sami ethnicity. More recently, Sami-language names seem to have been retained to a greater extent, possibly owing to the improved status of the culture.The third study looks at name changes in favour of names marked as Sami in character. The data consist in part of archive materials, but above all of interviews with three Sami informants who have themselves adopted Sami-language surnames. This study presents the informants’ thoughts on ethnicity and changes of name.In addition to the author’s own studies, the thesis includes a review of earlier research on Sami surnames, hereditary and non-hereditary, and a list of individual surnames with literature references regarding their origins and meanings. In the thesis, name changes are studied as a single, overall process, with an emphasis on the role of names in society, in particular as ethnic markers.
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| 7. |
- Hedner, Margareta, 1981-
(författare)
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Olfactory Function : The Influence of Demographic, Cognitive, and Genetic Factors
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Olfactory function is affected by demographic, cognitive, and genetic factors. In the present thesis, three empirical studies investigated individual differences in olfactory ability. Study I explored demographic and cognitive correlates in common olfactory tasks; odor detection, odor discrimination, and odor identification. The results indicated that old age influenced performance negatively in all tasks, and that semantic memory proficiency and executive functioning were related to odor discrimination and odor identification performance. No cognitive influence was observed for measurements of olfactory threshold. Using population-based data, Study II investigated a potential influence of the ApoE gene on olfactory identification after controlling for health status, semantic memory, and preclinical and clinical dementia. The main finding was that the ApoE- ɛ4 allele interacted with age, such that older ɛ4-carriers had an impaired odor identification performance relative to older non-carriers. Importantly, the negative ApoE- ɛ4 effect on olfactory proficiency was independent of clinical dementia conversion within five years. Study III investigated the effects of the BDNF val66met polymorphism on olfactory change over a five-year interval, in a community dwelling sample of young and old age cohorts. The results showed that age-related decline in olfactory identification was influenced by the BDNF val66met. In middle-aged subjects, no effect of BDNF val66met was observed although older val homozygote carriers showed a selectively larger olfactory decline than the older met carriers. Overall, results suggest that the relative influence of demographic and cognitive factors vary across different olfactory tasks and that two genes (ApoE and BDNF) impact age-related deficits in odor identification. Potential theoretical and practical implications of the findings are discussed as well as potential limitations of association studies in genomics research.
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| 8. |
- Henschen, Jonatan, 1989-
(författare)
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Bacterial adhesion to polyelectrolyte modified materials based on nanocellulose
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since the introduction of materials based on cellulose nanofibrils (CNFs), these materials have been studied extensively and are suggested to be suitable for use in, for example, hygiene and health care products. A property not very well studied but that could further increase the usability of CNF products is the possibility of controlling bacterial adhesion to the materials. Controlling and fine-tuning the bacterial adhesion makes it possible to produce contact-active antibacterial materials as well as anti-adhesive materials.The current thesis shows how the number of bacteria adhering to CNF-based materials can be altered through the adsorption of polyelectrolyte multilayers. Polyvinylamine (PVAm) and polyacrylic acid (PAA) were adsorbed in multilayers to achieve differently charged materials. The CNF substrates consisted of both crosslinked and non-crosslinked films with different surface charges and structures as well as porous aerogels.The results show the possibility of adsorbing PVAm/PAA to recharge the surfaces and construct multilayers. The polyelectrolyte adsorption was affected both by crosslinking and by changing the surface charge of the CNF films. Increasing the surface charge resulted in a decreased PVAm adsorption after the first polymer layer. Crosslinking the films resulted in a low initial PVAm adsorption, but as more layers were adsorbed, the PVAm adsorption increased similarly to the non-crosslinked films. The PVAm adsorption to the aerogels was lower than expected, taking into account their high surface area and surface charge, possibly due to crowding effects on the surface due to geometric limitations.Only the CNF films with the lowest surface charge and the aerogels adsorbed high numbers of bacteria from bacterial suspensions. The bacterial adsorption to the films was affected by the surface charge, the PAA adsorption and the PVAm adsorption, with a higher net surface charge leading to higher bacterial adsorption. The aerogels efficiently removed bacteria from the bacterial suspensions by adsorbing them onto their surface, with some samples removing over 99.9 % of the bacteria. The results presented in this thesis are believed to lead to a better understanding of both polyelectrolyte adsorption on CNF materials and bacterial adhesion to CNF materials and how polyelectrolyte multilayer adsorption can alter it.
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| 9. |
- Höglund, Anna, 1970-
(författare)
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Vampyrer : En kulturkritisk studie av den västerländska vampyrberättelsen från 1700-talet till 2000-talet
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Vampires haunt our culture. They live amongst us, they live with us, and very likely, they live for us. Considering the never fading popularity of vampires, it is obvious that these beings satisfy some kind of basic human need. Why are vampires so popular? What kinds of specific characteristics do vampires possess that lead to our never-ending fascination with them? These are questions that are answered in this dissertation, which deals with the vampire narrative’s most significant transformations during the period 1700-2000. This study reveals that the vampire is a monster that allows both identification and distance, which makes it into an appropriate character for people to use when they tell stories about themselves and the surrounding world. This is reflected in vampire narratives. The nature of vampires and the material of vampire narratives are not something that has undergone random changes in the course of history. These transformations have their origins in various societal and cultural processes. Through studying the historical and cultural contexts that have produced vampire narratives, one can understand why vampires have been portrayed in different ways at different times and places. Similarly, studying the vampire narrative can also be used to understand the history and culture in which the narrative was created. An examination of the vampire narrative’s history from a cultural criticism perspective reveals a distinct pattern. The vampire narrative has always attracted most attention in times of social and cultural unrest. In all of the varying contexts where vampire characters appear throughout a story, a power game is occurring – a game where the vampire’s character is strategically used to express political opinions and strengthen ideological beliefs. The constant appearance of vampires in such power games is a distinctive feature within the history of vampire narratives, and the societal turbulence leaves its impression on the vampire narrative. These impressions are analyzed and interpreted in this dissertation in order to reveal the power and the strategies of power within the discourse in which the narrative has been produced. In order to describe how the vampire character has functioned and continues to function in what the study calls conflicts of power relations, the term and phenomena power improvisation is used. In the description of the history of the vampire narrative, one can discern two important sub-processes. The first describes how the vampire character and narrative have been fashioned into what they are today. During the period of interest, the vampire is transformed from the un-dead of folklore to an attractive nobleman and further into to a Count Dracula, in order to simultaneously be portrayed as what this study terms a human vampire. The second sub-process explains why the vampire character and narrative have been fashioned into what they are today. It describes the political and ideological beliefs which exist in the society where the vampire form is created and which give birth to different kinds of vampires. If, in the past, the vampire was a monster that was used to portray that which humans are afraid of, today it is a monster with which humans identify. This, claims the author, is due to the fact that the age in which we live is to a great extent imbued with the logic of consumer culture. People in a consumer culture live lives filled with demands which influence their self-image. Feelings of inadequacy and isolation are typical. For people of today, the vampire is an ally that offers an alternative and meets those needs that are neglected in a consumer society.
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| 10. |
- Jakobson Mo, Susanna, 1968-
(författare)
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Nuclear medicine methods in idiopathic Parkinsonism : pre- and postsynaptic dopamine SPECT
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Single photon emission computed tomography (SPECT) with dopamine transporter (DAT) and dopamine D2 receptor (D2R) ligands can visualise the integrity of the nigrostriatal dopamine system. Parkinson’s disease (PD) and the atypical parkinsonian diseases (APD), progressive supranuclear palsy (PSP) and multiple system atrophy (MSA), have similar symptoms and dopamine depletion, but differ in pharmacological response and prognosis. Clinical differentiation between PD and APD is often difficult in the early stages. The aims of the thesis were to evaluate the differential diagnostic and prognostic value of SPECT in early PD, MSA and PSP, to map the pattern of progression with dopamine SPECT, and map the pattern of dopamine SPECT in non-affected elderly volunteers with a prospective approach. Also, we evaluated the methodological aspects of dopamine SPECT with respect to image evaluation tools, reconstruction parameters and gamma cameras.Methods: 172 patients, included in an on-going clinical prospective study on idiopathic parkinsonism, participated in the SPECT study. Also, 31 age-matched healthy controls (HC) were followed within this study. SPECT was done with 123I-FP-Cit (DAT SPECT) and 123I-IBZM (D2R SPECT). Regions of interest (ROI) were used as a standard method for semi-quantitative image analysis.Results: SPECT uptake ratios from different gamma cameras could be equalised through correction equations derived from images of a brain-like phantom, provided that attenuation correction was applied. The ROI method had high reproducibility. SPECT uptake in HC, measured with the ROI method and a volume based (VOI) method rendered similar trends, but gender and age differences in SPECT uptake were more marked with the VOI method, and less pronounced in DAT SPECT compared to D2R SPECT with both methods. The DAT SPECT uptake was significantly reduced in very early disease stage of PD and APD compared to HC. DATSPECT uptake was more reduced in PD with postural and gait disturbance (PIGD) compared to tremor-dominant PD. Decline in DAT SPECT uptake during the first year was more pronounced in PD and PSP compared to HC. D2R SPECT uptake overlapped between untreated PD and APD. After initiated treatment, the D2R SPECT uptake was significantly higher in MSA patients compared to PD, PSP and HC. Decline in D2R SPECT uptake during the first year was not significantly different between patients or compared to HC.Conclusions: 123I-FP-Cit SPECT is a valuable and sensitive method to detect early stage idiopathic parkinsonism. A different level of uptake between PIGD-PD compared to TD-PD indicates a prognostic potential. It is not possible to differ between PD, MSA and PSP in early stage with 123I-FP-Cit SPECT and no differential diagnostic value was found using 123I-IBZM SPECT in the early, untreated stage of PD, MSA and PSP. A different pattern of uptake of this ligand in MSA compared to PD and PSP during the first years of L-dopa treatment may, however, indicate a diagnostic value during the follow-up period.
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| 11. |
- Kalered, Emil, 1988-
(författare)
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Quantum chemical studies of deposition and catalytic surface reactions
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Quantum chemical calculations have been used to model chemical reactions in epitaxial growth of silicon carbide by chemical vapor deposition (CVD) processes and to study heterogeneous catalytic reactions for methanol synthesis. CVD is a common method to produce high-quality materials and e.g. thin films in the semiconductor industry, and one of the many usages of methanol is as a promising future renewable and sustainable energy carrier. To optimize the chemical processes it is essential to understand the reaction mechanisms. A comprehensive theoretical model for the process is therefore desired in order to be able to explore various variables that are difficult to investigate in situ. In this thesis reaction paths and reaction energies are computed using quantum chemical calculations. The quantum-chemical results can subsequently be used as input for thermodynamic, kinetic and computational fluid dynamics modelling in order to obtain data directly comparable with the experimental observations.For the CVD process, the effect of halogen addition to the gas mixture is studied by modelling the adsorption and diffusion of SiH2, SiCl2 and SiBr2 on the (0001̅) 4H-SiC surface. SiH2 was found to bind strongest to the surface and SiBr2 binds slightly stronger than the SiCl2 molecule. The diffusion barrier is shown to be lower for SiH2 than for SiBr2 and SiCl2 which have similar barriers. SiBr2 and SiCl2 are found to have similar physisorption energies and bind stronger than the SiH2 molecule. Gibbs free-energy calculations also indicate that the SiC surface is not fully hydrogen terminated at CVD conditions since missing-neighboring pair of surface hydrogens is found to be common. Calculations for the (0001) surface show that SiCl, SiCl2, SiHCl, SiH, and SiH2 likely adsorb on a methylene site, but the processes are thermodynamically less favorable than their reverse reactions. However, the adsorbed products may be stabilized by subsequent surface reactions to form a larger structure. The formation of these larger structures is found to be fast enough to compete with the desorption processes. Also the Gibbs free energies for adsorption of Si atoms, SiX, SiX2, and SiHX where X is F or Br are presented. Adsorption of Si atoms is shown to be the most thermodynamically favorable reaction followed by SiX, SiHX, and SiX2, X being a halide. The results in this study suggest that the major Si contributors in the SiC–CVD process are Si atoms, SiX and SiH.Methanol can be synthesized from gaseous carbon dioxide and hydrogen using solid metal-metal oxide mixtures acting as heterogeneous catalysts. Since a large surface area of the catalyst enhances the speed of the heterogeneous reaction, the use of nanoparticles (NP) is expected to be advantageous due to the NPs’ large area to surface ratio. The plasma-induced creation of copper NPs is investigated. One important element during particle growth is the charging process where the variation of the work function (W) with particle size is a key quantity, and the variation becomes increasingly pronounced at smaller NP sizes. The work functions are computed for a set of NP charge numbers, sizes and shapes, using copper as a case study. A derived analytical expression for W is shown to give quite accurate estimates provided that the diameter of the NP is larger than about a nanometer and that the NP has relaxed to close to a spherical shape. For smaller sizes W deviates from the approximative expression, and also depends on the charge number. Some consequences of these results for NP charging process are outlined.Key reaction steps in the methanol synthesis reaction mechanism using a Cu/ZrO2 nanoparticle catalyst is investigated. Two different reaction paths for conversion of CO2 to CO is studied. The two paths result in the same complete reaction 2 CO2 → 2 CO + O2 where ZrO2 (s) acts as a catalyst. The highest activation energies are significantly lower compared to that of the gas phase reaction. The presence of oxygen vacancies at the surface appear to be decisive for the catalytic process to be effective. Studies of the reaction kinetics show that when oxygen vacancies are present on the ZrO2 surface, carbon monoxide is produced within a microsecond. The IR spectra of CO2 and H2 interacting with ZrO2 and Cu under conditions that correspond to the catalyzed CH3OH production process is also studied experimentally and compared to results from the theoretical computations. Surface structures and gas-phase molecules are identified through the spectral lines by matching them to specific vibrational modes from the literature and from the new computational results. Several surface structures are verified and can be used to pin point surface structures in the reaction path. This gives important information that help decipher how the reaction mechanism of the CO2 conversion and ultimately may aid to improve the methanol synthesis process.
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| 12. |
- Karlsson, Pernilla
(författare)
-
Swelling of Cellulose Fibrillar Matrices and Gels
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the major challenges of today´s society is to find a sustainable way to create a living based on the resources on earth. It is a challenge that includes a transition from fossil-based materials to renewable/biodegradable raw materials and also the creation of an environmentally friendly circular material flow. In the search for renewable and biodegradable raw materials, the forest has gained renewed interest. In Sweden, 70 % of the area is covered with forest and, together with a long history of a sustainable forestry, this means that there are environmental and economic gains if this resource is utilized in a correct way and research and development into new wood-based materials has advanced significantly during the last decades. The wood component that has gained the most attention is cellulose and due to the ability of cellulose to act as a light-weight reinforcing component in composites and also due to the variability by which cellulose can be modified in order to obtain a wide range of useful properties. One advantage of cellulose-based materials is that they can be processed in water since the cellulose is hydrophilic and is softened by exposure to water. At the same time, this is one of the major drawbacks of cellulose-based materials since their properties deteriorate when exposed to water, whether as moist air or as condensed liquid. To optimize the use of cellulose fibers/fibrils/gels, knowledge of the effect on the inherent properties of cellulose in contact with water needs to be extended. This project has therefore focused on a fundamental understanding of the reasons behind the water uptake/swelling in a cellulose-rich fiber assembly immersed in water.The project has included the development and characterization of cellulose model materials in the form of gel (beads) and fibrillar (filaments) networks, for which the swelling was measured as a dimensional change in different aqueous environments. In one of the subprojects, the ion-induced swelling in different cellulose networks was measured on model materials and it was shown that the ion-induced contribution to the swelling was not only dependent on pH and salt concentration in the aqueous solution but also on the stiffness and structure of the network. Thermodynamic models describing gel swelling were used to separate and quantify the osmotic pressure associated with different factors contributing to the total osmotic pressure (ions, mixing and network) of never-dried gel beads. It was thus possible to identify the factor which had a dominant influence in the osmotic pressure and hence most important on the swelling of the systems. Never-dried gel beads showed that the network entropy was the most important factor controlling the swelling of the beads up to a volume fraction of cellulose of 35 %. Above this volume fraction the mixing entropy was found to dominate the swelling. It was also found that the distribution of the total osmotic pressure on these three factors was dependent on the network structure, as the distribution changed when the beads were dried and rewetted compared to the never-dried beads. Finally the de-watering ability of the gel beads in different environments was studied, and also after different modifications targeting the properties shown to have the most dominant effect on the osmotic swelling pressure (ion, mix and network). It was possible to quantify how the gel beads were dewatered to different degrees if e.g. hydrogen was chosen as the counter-ion to the carboxyl groups, if the polarity of the solution was lowered and if the structure of cellulose was changed. This information can, for example, be used to predict how nanocellulose based networks are dewatered under different conditions and this is essential for the preparation of materials based on cellulose nanofibrils.
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| 13. |
- Larsson, Lars, 1969-
(författare)
-
När EU kom till byn : LEADER II - ett sätt att styra landsbygdens utveckling
- 2002
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to analyse changes in political and territorial organisation that followed the introduction and implementation of the EU initiative for rural development, LEADER II, in Sweden. Focusing on the actors involved, the LEADER process is analysed from three perspectives: local democracy; the construction of regions; and the political capacity to act. Governance is the conceptual framework that guides the analysis. The main empirical material consists of 85 interviews conducted with people who actively participated in LEADER II. The LEADER programme is aiming at transgressing existing boundaries between societal sectors. It is done through the creation of partnership organisations and new regions. Viewed from a governance standpoint, the inclusion of actors from the private and non-profit sectors promises higher efficiency in delivering political goods through added resources and increased local knowledge. However, even if governance indicates that new forms for political implementation can be experimented with there are limits to what can be achieved. In the LEADER case, it is clear that the public sector retained its power over resources, means and ends.
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| 14. |
- Larsson, Oscar, 1978-
(författare)
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The Governmentality of Meta-governance : Identifying Theoretical and Empirical Challenges of Network Governance in the Political Field of Security and Beyond
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Meta-governance recently emerged in the field of governance as a new approach which claims that its use enables modern states to overcome problems associated with network governance. This thesis shares the view that networks are an important feature of contemporary politics which must be taken seriously, but it also maintains that networks pose substantial analytical and political challenges. It proceeds to investigate the potential possibilities and problems associated with meta-governance on both theoretical and empirical levels.The theoretical discussion examines meta-governance in relation to governmentality, and it puts forward the claim that meta-governance may be understood as a specific type of neo-liberal governmentality. The meta-governance perspective regards networks as a complementary structure to traditional administration that can be utilized in the implementation and realization of public policy, but which also preserves the self-regulating and flexible character of networks. This generates a contradiction between the goals of public management and the character of networks that requires further investigation.The combination of the specific dynamics of the political field of security, the diminishing role of sovereign powers, the emergence of security networks, and the meta-governance stance adopted by the Swedish state constitutes a situation that should have been favorable for the successful employment of meta-governance. The empirical investigation of meta-governance is divided into two parts. The first part reviews the historical process involved and shows how the Swedish government and public authorities have adopted a meta-governance stance. The second analyzes the specific instruments and strategies that have been deployed in the governance of security communications and in the management of Sweden’s new security communications system which is an important aspect of security networks. The historical study together with the analysis of the meta-governance tools deployed reveals that the meta-governors neither reached the goals specified, nor fulfilled the overall purpose of successful security communications.I argue on the basis of the theoretical and empirical findings obtained in the present study that it is very difficult to successfully employ meta-governance in respect to security and crisis management, and that we have sound reasons to suspect that meta-governance will run into similar difficulties in other political fields as well. I conclude that meta-governance is a far more difficult practice than has been anticipated by existing theories and policy recommendations. Turning to meta-governance as a way to govern and control organizations may in fact lead to further fragmentation and distortion of public politics.
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| 15. |
- Larsson, Per A., 1980-
(författare)
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Dimensional Stability of Paper : Influence of Fibre-Fibre Joints and Fibre Wall Oxidation
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Papper är ett mycket mångsidigt material. Trots detta finns det ett flertal egenskaper som begränsar papperets användbarhet. Ett av de större problemen med cellulosa- och lignocellulosafibrer är att de sänker sin fria energi genom att sorbera vatten, och denna sorption förändrar papperets dimensioner. Detta fenomen kallas vanligtvis för bristfällig dimensionsstabilitet och uppträder i form av registerfel vid flerfärgstryck eller som krullning, buckling och vågiga papperskanter vid utskrift, kopiering och lagring, eller med en vidare definition som förkortad livslängd hos lådor på grund av mekanosorptivt kryp. Avsikten med denna avhandling har varit att studera och kvantifiera vilka egenskaper som styr, och hur de påverkar, den vatteninducerade dimensionsförändringen som sker hos ett fibernätverk, samt hur dess dimensionsstabilitet kan förbättras. Detta har studerats både genom att ändra fiberns fuktsorptionsegenskaper och genom att förändra adhesionen och kontaktgraden mellan fibrerna i fiber-fiberfogarna. Fogegenskaperna har också varierats genom att tillverka laboratorieark torkade under inspänning samt ark torkade fritt för att minimera mängden inbyggda spänningar i arket. Blekt kraftmassa har behandlats med polyelektrolytmultilager (PEM) för att förbättra adhesionen mellan fibrerna och för att öka kontaktgraden mellan fibrerna i fogen. Kontaktgraden har även minskats genom förhorning av fibrerna före arkformning. För de ark som fick torka fritt gav PEM-behandlingen en ökad hygroexpansionskoefficient, det vill säga dimensionsförändringen normaliserad mot förändringen i fuktinnehåll, vid samma förändring i relativ luftfuktighet medan förhorningen minskade hygroexpansionskoefficienten något. Om arken emellertid torkades under inspänning observerades ingen skillnad i hygroexpansionskoefficient mellan de olika fibermodifieringarna. Detta tolkades som ett resultat av en ökad kontaktzon och en större utbredning ut ur fogens plan, när arken torkades utan inspänning. En utbredning som medför att en större del av fiberns transversella expansion överförs som expansion i pappersplanet. Fibrernas fuktsorptionsegenskaper förändrades genom natriumperjodatoxidering av 1,4-glukanernas C2-C3-bindning. Detta skapade sannolikt tvärbindningar i fiberväggen som förbättrade fiberväggens tålighet både genom att låsa fibrillerna närmare varandra och genom att ta bort potentiella adsorptionssäten som annars är tillgängliga för vattenadsorption. Perjodatoxidationen minskar också fibrernas kristallinitet och således frigjorde oxidationen hydroxylgrupper där vattenmolekyler kan adsorbera. Detta innebar att oxidationen både minskade och ökade interaktionen mellan vatten och fibervägg, men dock på olika strukturell nivå. Tvärbindningarna visade sig också märkbart reducera sorptionshastigheten när arken utsattes för en förändrad luftfuktighet så länge de inte tidigare utsatts för relativa luftfuktigheter nära mättnad. Som ett resultat av den lägre förändringen i fuktinnehåll vid en förändring i luftfuktighet från 20 till 85 % RF minskade dimensionsförändringens amplitud för de tvärbundna arken upp till 30 %. Emellertid uppvisade de tvärbundna arken en högre hygroexpansionskoefficeint, vilket innebär att de blev mer känsliga för absoluta förändringar i fuktinnehåll.
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| 16. |
- Larsson, Peter, 1966-
(författare)
-
On Performance Analysis of Retransmission Schemes with Fading Channels
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Future wireless communication systems and services bring increased performance demands, with respect to data-rate(s), reliable communication, (stochastic) real-time guarantees, and more. In this context, not only new communication schemes are needed, but also more capable performance analysis methods are essential. Digital wireless communication systems convey information (digital messages, as data packets) inherently susceptible to errors when communicated. In this respect, fading channels, receiver noise, and interference, are often the main causes of errors. State-of-the-art wireless systems use, e.g., retransmissions (and channel coding) to correct possible remaining errors in communicated message. Retransmissions of erroneous messages are generally known, under the umbrella-term, as automatic repeat request. Adopting a modern terminology (see Chapter 2.2), the three main schemes are here denoted; automatic repeat request (ARQ), repetition redundancy hybrid-ARQ (RR-HARQ), and incremental redundancy hybrid-ARQ (IR-HARQ). There are at least three factors that motivate further performance studies of the ARQ-, RR-, and IR-schemes. First, many commercially important and extensively deployed wireless systems, e.g. cellular systems, use those (H)ARQ-schemes as core system components. Second, those schemes are often integrated with various (recently invented) communication schemes, such as multiple-antenna systems, which promote the need of further studies. Third, the information theoretically-based performance characterization of those (H)ARQ-schemes is, in our view, only in its infancy, and only a few closed-form expressions for very basic (H)ARQ-cases exists in the literature. The thesis deals, on a high level, with the problem of developing performance analysis methods for (H)ARQ-schemes, and, on a more detailed level, studying particularly important (H)ARQ-cases, i.e. with respect to (wrt) (H)ARQ-scheme, fading statistics, antenna-scheme, etc. In doing so, the thesis addresses tools and models that support, ease, or strengthen the analysis.We start our study with a basic throughput analysis of (H)ARQ (Chapter 4). A general throughput expression for HARQ is given in terms of the Laplace-transform (LT) for the probability density function (pdf) of a so called effective-channel. Here, the effective-channel represents the signal-to-noise-ratio (SNR), or mutual information (MI), after signal processing. We then focus on some important (H)ARQ-cases and give closed-form throughput expressions in a general diversity (GD) channel, accounting for space-time-block coding (STC), maximal ratio combining (MRC), and Nakagami-m fading. The throughput of (H)ARQ can, in many cases, be maximized by tuning the initial transmission rate. However, analytical throughput optimization has proven challenging to solve even for the simplest (H)ARQ-cases. We propose a parametric optimization approach, based on judiciously chosen parameter, that allows expressions for the optimal throughput, and the optimal rate point, to be given in closed-forms (Chapter 5). The method is demonstrated for several important, but previously not handled, (H)ARQ-cases. An inherent assumption in this thesis, shared with many other works in wireless communication analysis, is the assumption of that the average symbol MI equals the additive white Gaussian noise (AWGN) channel capacity. The underlying assumption is that the communication symbol can be modeled as an independent and identically distributed (iid) complex Gaussian random variable (r.v). However, practical systems use discrete modulation, not a continuous r.v. Quadrature amplitude modulation (QAM) is the most common (discrete) modulation format in communication systems. Unfortunately, QAM exhibits an asymptotic 1.53 dB SNR-gap relative to the AWGN channel capacity. We substantiate the assumption, of modeling the communication signal as iid complex Gaussian, and close the SNR-shaping-gap, by proposing a novel modulation framework inspired from packing arrangements (spiral-phyllotaxis) among plants (Chapter 6). Much work on wireless performance analysis focus on specialized fading channel gain models, such as exponentially- or gamma-distributed fading. We introduce the idea of a matrix exponential (ME) distributed effective channel SNR (Chapter 7). The ME-distribution is dense on the positive axis, and includes the exponential- and gamma-distribution as special cases. With the ME-distributed channel at hand, we develop an overall ME-distribution-based framework that simplifies the performance analysis and directly express performance measures in the ME-distributed (effective) channel parameters. It has proven hard to analyze (H)ARQ with interference via standard methods, and only special cases have previously been handled successfully. With the ME-distribution-based performance analysis framework, we can now analyze interferers with ME-distributed SNRs. Numerous closed-form throughput expressions are also given in terms of ME-distribution-based channels. Up to this point, the performance measure of choice has been throughput. However, communication systems may impose delay requirements. For this purpose, the effective capacity, giving an indication of communication rate for a given maximum delay and delay violation probability, is a more suitable performance measure. We formulate a very general retransmission system model (allowing for multiple transmissions, multiple communication modes, and multiple rate increments), going beyond classical ARQ-, RR-, and IR-models, and develop a powerful recurrence-based effective capacity performance analysis framework (Chapter 8).Thus, to summarize on a high-level, we introduce a simplifying LT-based performance analysis framework, develop a powerful auxiliary-parameterized throughput optimization method, propose a novel AWGN channel capacity approaching (golden angle) modulation scheme, introduce the ME-distributed channel, develop the ME-distribution-based performance analysis framework, design a highly general retransmission system model, and propose a recurrence-based (effective capacity) performance analysis framework. Throughout the thesis, numerous new closed-form performance expressions are given built on the tools and models introduced in the preceding chapters.
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| 17. |
- Lauritz, Lars Erik, 1965-
(författare)
-
Spirande polisidentiteter : En studie av polisstudenters och nya polisers professionella identitet
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Who am I? Who are we? And how are the two entities connected? These are key issues of this study. Socialization and other sense making processes create new social identities. One possible identity is a professional one. Professional identities are discussed as a construction where expectations and experiences of construed images, cultural and professional understandings are key elements. Social identities are fundamentally described as social and individual reflections. The purpose of the study is to extend the comprehension of how professional identities are constructed and to study new professionals navigation through the complex network of images and contrasting pictures that meet them in that process. The professional identity of Swedish police officers is focused. The profession is - by many of the ten informants in this recurrent, in-depth interview study - described as a dream from childhood. The first of four interview-series has been conducted in beginning of police education, the last after nine months work experience. There are two motives that all informants mention for choosing the profession. The first is a wish to care for others and for the society, the second is excitement. Other mentioned motives are the police profession regarded as teamwork with a high community spirit. It is expected to give good opportunities to develop as individuals and is thought to be a practical occupation, described with key words such as handy and flexible. The construed image, how informants believe that others view the profession, is described either as polices as the selected model or as prejudiced and hostile. The mass media is regarded the main intermediary of the second image. By the informants, a good police is regarded as being without prejudices and is presented as male. Male strength is one desirable quality, though the strength preferably can be combined with female softness. The care-giving motive is accentuated as the most important one in the first interviews, but replaced by excitement as the most important one in practice. Some general discourses are discussed. The first three - the social, the recruitment, and the distrust discourse - are discussed as sources of understanding to the frequently discussed notion of the police profession as constituting strong team spirit. Police identity is also presented as unprejudiced, male and young in the sense of engagement and activity degree. All discourses are often challenged in work- experience, from cultural as well as from image perspectives. On a highly generalized level the police identity can be positioned as one with a high degree of community. When the stories are scrutinized clearly disparate patterns between individuals however appear. The differences are expressed either in accentuation or definition of the common labels. Earlier research on the fields of identity reveals some shortages. The individual's role in constructing social identities and the pure locus of identity is overlooked. To reduce that shortage, this study introduces a professional identity model where the individual´s position is connected to the common identity by expectations and experiences of three key identity elements -Culture, Image and the Profession itself.
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| 18. |
- Lefébure, Robert, 1980-
(författare)
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Effects of temperature and terrestrial carbon on fish growth and pelagic food web efficiency
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Both temperature and terrestrial dissolved organic carbon (TDOC) have strong impacts on aquatic food web dynamics and production. Temperature affects vital rates of all organisms and terrestrial carbon has been shown to alter the dynamics of phytoplankton and bacterial production and affect the trophic structure of planktonic food webs. As climate change predictions for the Baltic Sea suggests future increases in both terrestrial carbon run-off and increases in temperature, the aim of thesis was to adopt a system-ecological approach and study effects of these abiotic variables, not only on interactions within planktonic food webs, but also on the growth and consumption rates of one of the most common zooplanktivorous fish in the Baltic Sea, the three-spined stickleback Gasterosteus aculeatus. Results showed that three-spined sticklebacks display a high degree of resilience against increasing temperatures, as both growth rates as well as consumption rates on zooplankton were high at temperatures well over 20 °C. Furthermore, it was shown that the minimal resource densities required to sustain individual and population growth, actually decreased with increasing temperatures, implying that sticklebacks around their optimum temperature for growth at 21 °C will actually have an increased scope for growth. As stickleback population densities have increased over the last decade in the Baltic Sea and are now suggested to out-compete other coastal fish species for shared zooplankton resources, the results presented in this thesis suggest that increased water temperatures would only serve to increase sticklebacks competitive advantage. As the structuring role of this small zooplanktivore on pelagic communities might be considerable, further studies investigating competitive interactions as well as patterns of population abundances are definitely warranted. TDOC was overall shown to stimulate bacterial production and the microbial food web. Because of the longer trophic pathways required to transport carbon from bacterial production to higher trophic levels, the addition of TDOC always reduced food web transfer efficiency. However, it became apparent that the full effect of TDOC additions on pelagic food webs was complex and depended heavily not only on the existing trophic structure to which the carbon was introduced, but also on ambient temperature levels. When three-spined sticklebacks were part of food webs with significant TDOC inputs, the presence of fish, indirectly, through predator release of lower trophic levels, amplified the magnitude of the effects of carbon addition on bacterial production, turning the base of the system significantly more heterotrophic, which ultimately, impacted negatively on their own production. However, when a pelagic food web containing sticklebacks was simultaneously subjected to realistic increases in temperature and TDOC concentrations, food web efficiency and fish production increased compared to present day conditions. These results were explained by a temperature dependent increased production potential of zooplankton, sustained by an increased production of heterotropic microzooplankton via TDOC additions, which lead to higher fish production. Although the increased number of trophic linkages in heterotrophic food webs should have reduced energy transfer efficiency, these negative effects seem here to have been overridden by the positive increases in zooplankton production as a result of increased temperature. These results show that heterotrophic carbon transfer can be a viable pathway to top-consumers, but also indicates that in order to understand the full effects of climate change on trophic dynamics and fish production, abiotic variables cannot be studied in isolation.
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| 19. |
- Ljungström, Lars, 1956-
(författare)
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Magnus Gabriel De la Gardies Venngarn : Herresätet som byggnadsverk och spegelbild
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Starting in about 1640, Sweden experienced a building boom among the nobility lasting up to 1680, when Charles XI initiated a massive withdrawal of Crown fiefs. Based on contemporary Swedish sources, the strategies and ideology behind these large new houses are discussed in connection with questions concerning visual identity – corporate as well as individual. Opinions held in the Swedish debate are compared with the characteristics described by Volker Bauer in his analysis of competing German court ideal types, and are found strikingly reminiscent. This approach constitutes the framework for a close examination of Venngarn, one of Count Magnus Gabriel De la Gardie´s country houses, rebuilt and considerably enlarged from 1661 and onwards. De la Gardie was Rikskansler, Chancellor of the Realm, a dominating magnate and one of Sweden´s most eager building patrons. The remodelling of Venngarn was begun at a time when major works were in progress at five other estates, at the palace in Stockholm and his father´s burial chapel. Other projects were to follow suite. At Venngarn the idea of an ideal correspondence between the level of Magnificentia and the individual´s station is expressed by a systematic gradation of the apartments. Another court ideal, that of the prince (or aristocrat) as a disciple of the Muses, was just as befitting an attribute. The most telling example is the 'learned' décor of the chapel. More than fifty emblems, parables and devotional subjects are found to be organized according to a comprehensive programme, combining important tendencies in contemporary Lutheran spirituality, on the one hand themes from Johann Arndt, on the other the dogma of Ordo salutis. A more mundane aspect of aristocratic behaviour was villeggiatura, or the preference for temporary retreats from urban life and public affairs. De la Gardie has left several drafts defining the weekly round of a country life and aiming at an otium, as recommended by Seneca, Cicero and the neo-Stoics. Several circumstances indicate that De la Gardie considered this a component of a true statesman´s life and that Venngarn and his other country houses were to serve such a purpose.In these and other ways, De la Gardie could be said to have arranged the house at Venngarn as an ideal mirror image of his persona, an image that would testify to his greatness and further his reputation.
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| 20. |
- Mohammadi, Mohammad
(författare)
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Probabilistic time estimation in tunnel projects
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Transport infrastructure projects, including tunneling, suffer from timedelays and cost overrun. A literature review shows that the effect ofuncertainty has been neglected in explaining time and cost overrunmeaning that technical explanations matter. Probabilistic estimations oftime and cost can be employed for dealing with uncertainty in transportinfrastructure projects.In this licentiate thesis, KTH’s probabilistic time and cost estimationmodel for tunneling projects (Isaksson and Stille, 2005, Rock Mech. RockEng., 38, 373-398) was improved. The improvements include breakingdown the production activities into their sub-activities, which form thebasis for assessing times (or costs) for tunnel construction. In addition, theexceptional time and the length of model’s geotechnical zones aredescribed as stochastic variables instead of deterministic values used in theoriginal model. Given its hierarchical structure, the model can be used fortime and cost estimation of all types of tunnels and all constructionmethods in various geological condition.The improved version of the model uses three types of input parametersthat are probabilities of occurrences of different geological condition andidentified undesirable events, production effort of sub-activities (i.e. timespent for performing the sub-activity per unit length of tunnel) andadditive delay time that is imposed as a result of occurrence of undesirableevents. The important issues in modeling the uncertainty in the productionefforts of sub-activities are also explained.
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| 21. |
- Olsson, Mikael, 1966-
(författare)
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Ownership reform and corporate governance : The Slovak privatisation process in 1990-1996
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since 1989, there has been a period of rapid change of the economies of the former Eastern bloc. Within a few years, the majority of the formerly centrally administered economies had begun restructuring their economic systems, including the privatisation. of formerly state-owned enterprises. This process developed differently in different countries, depending among other things on their historical traditions and the momentum of their social, political and economic transformations. This doctoral dissertation examines the privatisation of large-scale industrial enterprises in Slovakia prior to 1997. In particular the thesis analyses the changing political and institutional framework governing the process and method of privatisation; and how the governance of firms was affected by the new markets and ownership- and control-structures that were established. Special attention is paid to the role played by investment funds andinvestment-companies established as a consequence of voucher privatisation. The research problem is approached both from an aggregate national level and from the enterprise level. The thesis includes a number of case studies of enterprises in Slovakia that underwent privatisation, and of investment funds that emerged to take part in the process. In addition, two panel-data sets were constructed for the sake of statistical analysis. The study points to the drastic changes in privatisation policy and its enactment, under different governments. It leads to the conclusion that privatisation is a highly political process, whose economic effects cannot be separated from its distributional effects. This politicised nature of ownership reform is shown to have some negative side-effects with regard to the development of well-functioning governance structures. It is, for example, pointed to that the capital market, as it developed during the period of study, was highly non-transparent,characterised by high transaction costs and insider-trading. The study also documents an increasingly concentrated ownership structure of the Slovak industry and relates it to the changes in privatisation policy. In the final analysis attention is drawn to a recurring theme in the study, namely the issues related to the relative stability and durability of the institutional set-up. In many cases an insecurity about "the rules of the game" led to short-term incentives and opportunism on behalf of the economic and political agents.
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| 22. |
- Rahman, Mashuqur, 1984-
(författare)
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In-line rheology of cement grouts - Feasibility study of an ultrasound based non-invasive method
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Grouting is used in underground construction to reduce the water flow into tunnels and caverns and to limit the lowering of the surrounding groundwater table. Due to their wide availability and low cost relative to other materials, cement based materials are commonly used as grouts and, in this context, the rheology of the cement grout is an important factor. Rheological properties of cement grout such as viscosity and yield stress are commonly measured off-line using laboratory instruments, and some simple tools are available to make field measurements. However, these methods often lack accuracy and reliability. Although the rheological properties of the grout used play a fundamental role in design and execution, no method has yet been developed to measure these properties in-line in field work. In this work, for the first time, an in-line rheometry method combining the Ultrasound Velocity Profiling (UVP) technique with Pressure Difference (PD) measurements, known as “UVP+PD”, was successfully tested for continuous in-line measurements of concentrated micro cement based grouts. The feasibility of using the UVP+PD method depends on the in-line determination of the rheological properties and time dependent behaviour of the cement grouts. A test set-up consisting of a combination of an experimental “flow loop” and a conventional field grouting rig – UNIGROUT E22H – from AtlasCopco, was used to investigate the feasibility of determining the rheological properties of cement grout using the UVP+PD method under field conditions. A laboratory based test set-up was used to further investigate the rheological properties in a more controlled environment. The velocity profiles were measured directly in-line. The shape of the velocity profiles was visualized, and the change in the shape of the profiles with concentration and time was observed. The viscosity and yield stress of the grout were determined using rheological models, e.g. Bingham and Herschel-Bulkley. In addition, rheological properties were determined using the non-model approach (gradient method) and the tube viscometry concept and were compared with results obtained using the rheological models. In addition, the obtained rheological properties were subsequently compared with off-line measurements using a conventional rotational rheometer. The UVP+PD method was found to be capable of determining the true rheological behavior of cement grout regardless of the rheological model, providing the opportunity to visualize the change in the shape of the velocity profiles. Furthermore, it was possible to make an accurate determination of the velocity by ultrasound velocity profiling at a very flow rate (i.e. 1liter/min). The ultrasound velocity profiling was also found to be a reliable tool for determining the characteristics of the grout pump. In conclusion, the UVP+PD method was demonstrated to be a promising new in-line tool for determining the rheological properties of commonly used cement based grouts and the changes with concentration and time.
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| 23. |
- Sellman, Farhiya Alex
(författare)
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Characterization and Utilization of Interactions in Wet and Dry Cellulose Nanofibrillar Networks
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Expanding our understanding of how cellulose fibers and fibrils interact with water and its effect on their inherent properties is needed to optimize their utilization in the making of novel bio-based materials, but also useful in more traditional products (pulp, paper, and packaging).The overall objective of the work in this thesis was to deepen the understanding of drying-induced structural changes and cellulose-water interactions using cellulosic model materials. Cellulose nanofibrils (CNFs) were employed as they present a distinct advantage with their defined geometry and controlled surface chemistry compared to macroscopic cellulose fibers.The first part considers the fundamental interactions of CNFs in contact with water and by water removal, and is devoted to identifying the molecular mechanisms behind the process known as hornification. This was done by studying the exposure of CNF sheets to different heat treatments to establish a connection between their reswelling properties, chemical and structural characteristics, and mechanical behavior. The findings indicate that hornification is governed by non-covalent interactions and that the diffusion of water back into a hornified CNF network is kinetically limited. Furthermore, the influence of fibril aspect ratio and chemical functionality on the mechanical properties of wet fibrillar networks was studied. Fibrils were prepared from fibers with different hemicellulose content. It was found that longer fibrils formed stiffer and more ductile materials, owing to a longer-range and more uniform distribution of stress transfer. Additionally, high aspect ratio fibrils form networks capable of holding larger amounts of water. It was also possible to elucidate the influence of aspect ratio on the network formation, where long and short fibrils form networks with different topologies. These results were integrated into a mechanical network model to present an improved elastoplastic description of the network properties.The second part of the thesis presents potential applications where control of the water uptake in the fibrillar networks is required. Anisotropic fibrillar hydrogels were prepared to function as actuators and superabsorbents. With the help of the knowledge built in the first part of the work, the water uptake in the fibrillar networks could be maximized. This resulted in CNF hydrogel actuators far surpassing conventional hydrogel used in actuation performance and integration of CNF sheets in a superabsorbent heterostructure, where the most strongly immobilized water can be retained at high pressures.
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| 24. |
- Sundström, Johan, Professor, 1971-, et al.
(författare)
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Risk factors for subarachnoid haemorrhage : a nationwide cohort of 950 000 adults
- 2019
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Ingår i: International Journal of Epidemiology. - : Oxford University Press. - 0300-5771 .- 1464-3685. ; 48:6, s. 2018-2025
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Subarachnoid haemorrhage (SAH) is a devastating disease, with high mortality rate and substantial disability among survivors. Its causes are poorly understood. We aimed to investigate risk factors for SAH using a novel nationwide cohort consortium.METHODS: We obtained individual participant data of 949 683 persons (330 334 women) between 25 and 90 years old, with no history of SAH at baseline, from 21 population-based cohorts. Outcomes were obtained from the Swedish Patient and Causes of Death Registries.RESULTS: During 13 704 959 person-years of follow-up, 2659 cases of first-ever fatal or non-fatal SAH occurred, with an age-standardized incidence rate of 9.0 [95% confidence interval (CI) (7.4-10.6)/100 000 person-years] in men and 13.8 [(11.4-16.2)/100 000 person-years] in women. The incidence rate increased exponentially with higher age. In multivariable-adjusted Poisson models, marked sex interactions for current smoking and body mass index (BMI) were observed. Current smoking conferred a rate ratio (RR) of 2.24 (95% CI 1.95-2.57) in women and 1.62 (1.47-1.79) in men. One standard deviation higher BMI was associated with an RR of 0.86 (0.81-0.92) in women and 1.02 (0.96-1.08) in men. Higher blood pressure and lower education level were also associated with higher risk of SAH.CONCLUSIONS: The risk of SAH is 45% higher in women than in men, with substantial sex differences in risk factor strengths. In particular, a markedly stronger adverse effect of smoking in women may motivate targeted public health initiatives.
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| 25. |
- Wilson, Karin, 1955-
(författare)
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Markusevangeliet i Lars Rangius samiska översättning från 1713
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lars Rangius translated the New Testament into Ume Saami in 1701–1713. The manuscript, comprising over 1000 pages, was never printed and is kept in The University Library in Uppsala. This study includes a transliteration of the Gospel of St. Mark and a description of the language. The language is studied from a phonological, morphological, syntactic and lexical point of view. An overview of the historical circumstances under which the translation was done is given and an investigation into the life of the translator, Lars Rangius, is also made in order to understand why he made this extensive work.
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| 26. |
- Atoufi Najafabadi, Zhaleh
(författare)
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Development and Tailoring of Low‐Density Cellulose‐Based Structures for Water Treatment
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The challenges posed by our limited clean water sources and the well-known global water pollution demand more efficient water purification technologies. Additionally, the increasing environmental awareness has inspired a shift towards eco-friendly and renewable materials and technologies. This thesis is focused on developing effective adsorbent materials from renewable resources to eliminate organic solvents, dyes, and metal ions from water. Cellulose, the most abundant biopolymer in nature, is the main component used to develop new materials in the present study. Its distinctive physical and colloidal properties, in the form of nanocellulose, along with tunable surface chemistry, play key roles in enhancing the effectiveness of the developed materials.The primary focus of the first part of the thesis was to develop a molecular layer-by-layer modification technique to customize the surface functionality of cellulose aerogels in a uniform and controlled manner. Through the sequential deposition of diamine and triacid monomers, exceeding lythin polyamide coatings were formed on the cellulose aerogels, altering the surface properties from hydrophilic to hydrophobic. This transformation made them well-suited structures for oil-water separation.Following this, a biohybrid aerogel was developed based on cellulose nanofibrils (CNFs) and amyloid nanofibrils (ANFs), the latter derived by heat treatment of β-lactoglobulin proteins. The pH-tunable surface charge of the aerogel, controlled by the amphiphilicity of the protein, allowed for the adsorption of both cationic and anionic contaminants by adjusting the pH of the solutions. Furthermore, the aerogels exhibited remarkable selectivity for lead (II) ions and they could also be regenerated and reused after each adsorption cycle without a significant loss of their adsorption capacity. This was to a large extent possible due to the excellent wet stability of these aerogels, which was achieved by crosslinking the CNFs during freezing and ice templating, eliminating the need for freeze-drying. However, a solvent exchange to acetone after melting was still necessary to reduce the influence of the capillary forces during drying to avoid the collapse of the aerogels. In a consecutive study, the foaming characteristics of the heat-treated β-lactoglobulin system were exploited to create highly stable Pickering foams with the aid of using CNFs as stabilizers and to physically lock the system through a controlled pH reduction. Interestingly, these Pickering foams could be directly oven-dried without collapsing, yielding low-density foams. Furthermore, it was demonstrated that the foams can be chemically crosslinked by incorporating chemical crosslinkers in the formulation or by pre-functionalizing the CNFs with dialdehydes. This crosslinking naturally also provided wet stability to the oven-dried foams.Finally, an innovative and environmentally friendly method was introduced to increase the charge of cellulose fibers by radical polymerization of acrylic acid from the fibers, enabling the preparation of fibers with an exceptionally high charge of 6.7 mmol/g. The introduction of these charged groups significantly enhanced the interaction of the fibers with methylene blue as a model dye and lead (II), Copper (II), and Zinc (II) ions as model metal ions, showing the huge potential of these fibers as building blocks for a wide range of adsorbent applications. Overall, this thesis demonstrates the development and characterization of several bio-based adsorbents for water remediation.
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| 27. |
- Bartusch, Cajsa, 1965-
(författare)
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Boosting behavioral change in residential electricity consumption : demand response programs and feedback
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As part of realizing national and European climate ambitions, it is imperative to bring about increased energy efficiency and consumption flexibility in the residential sector of the Swedish power market. In addition to governmental policy instruments to this end, market-based measures play an important role in making behavioral change in domestic electricity use happen. In light of the prevailing lack of incentives for residential consumers to save electricity and cut peak demand at times of physical and financial market constraints, the research studies that form the basis of this thesis have the aim of adding to the body of knowledge on policy instruments for the purpose of boosting behavioral change in residential electricity consumption. The research has accordingly contributed to the general statistics on residential electricity consumption, which constitute the starting point for policy instrument development, and augmented knowledge on the merits of residential demand response programs involving hourly settlements in power trading and demand-based, time-of-use tariffs in power distribution as well as graphic feedback on individual households’ electricity use by means of a statistics service provided over the Internet. The overall results have shown that household behavior, together with physical factors such as heating systems, help explain the sizeable differences in electricity consumption among homeowners. Statistical analysis of variance has in this context proven to be an effective method for identifying key indicators of policy development. Power suppliers and electricity consumers as well as society as a whole have been found to gain substantially from hourly settlements in retail. To suppliers, the greatest benefits are associated with risk management, while the major advantage to customers is that they are provided with an opportunity to reduce their electricity costs. It has also been empirically demonstrated that electricity users are willing to adjust their consumption to a demand-based, time-varying distribution tariff. Households generally have a favorable attitude towards this type of distribution tariff, seeing as they indirectly have a positive impact on the environment. Providing households with feedback over the Internet on their individual electricity use and demand has been shown to contribute to an increased awareness and lead to energy efficiency in homes. Easy accessibility and simplicity have proven to be key success factors in this context. Combining conventional bar charts, color symbolism and historic feedback is expedient in this respect.
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| 28. |
- Bjureland, William
(författare)
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Reliability-based design of rock tunnel support
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since 2009, design of rock tunnels can be performed in accordance with the Eurocodes, which allows that different design methodologies are applied, such as design by calculation or design using the observational method. To account for uncertainties in design, the Eurocode states that design by calculation should primarily be performed using the partial factor method or reliability-based methods. The basic principle of both of these methods is that it shall be assured that a structure’s resisting capacity is larger than the load acting on the structure, with sufficiently high probability. Even if this might seem straightforward, the practical application of limit state design to rock tunnel support has only been studied to a limited extent.The overall aim of this project has been to develop reliability-based methods for environmental and economic optimization of rock tunnel support, with a special focus on shotcrete support. To achieve this, this thesis aims to: (1) assess the applicability of the partial factor method and reliability-based methods for design of shotcrete support, exclusively or in combination with the observational method, (2) quantify the magnitude and uncertainty of the shotcrete’s input parameters, and (3) assess the influence from spatial variability on shotcrete’s load-bearing capacity and judge the correctness of the assumption that the load-bearing capacity of the support is governed by the mean values of its input parameters.The thesis shows that the partial factor method is not suitable, and in some cases not applicable, to use in design of rock tunnel support. Instead, the thesis presents a reliability-based design methodology for shotcrete in rock tunnels with respect to loose blocks between rockbolts and a design methodology for shotcrete lining based on a combination of the observational method and reliability-based methods. The presented design methodologies enable optimization of the shotcrete support and shotcrete lining by stringently accounting for uncertainties related to input data throughout the design process. The thesis also discusses the limited knowledge that we as an industry sometimes have in our calculation models and the clarifications that should be made in future revisions of the Eurocode related to target reliability and the definition of failure.
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| 29. |
- Björnfot, Cecilia, et al.
(författare)
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Cerebral arterial stiffness is linked to white matter hyperintensities and perivascular spaces in older adults : a 4D flow MRI study
- 2024
-
Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : Sage Publications. - 0271-678X .- 1559-7016. ; 44:8, s. 1343-1351
-
Tidskriftsartikel (refereegranskat)abstract
- White matter hyperintensities (WMH), perivascular spaces (PVS) and lacunes are common MRI features of small vessel disease (SVD). However, no shared underlying pathological mechanism has been identified. We investigated whether SVD burden, in terms of WMH, PVS and lacune status, was related to changes in the cerebral arterial wall by applying global cerebral pulse wave velocity (gcPWV) measurements, a newly described marker of cerebral vascular stiffness. In a population-based cohort of 190 individuals, 66–85 years old, SVD features were estimated from T1-weighted and FLAIR images while gcPWV was estimated from 4D flow MRI data. Additionally, the gcPWV’s stability to variations in field-of-view was analyzed. The gcPWV was 10.82 (3.94) m/s and displayed a significant correlation to WMH and white matter PVS volume (r = 0.29, p < 0.001; r = 0.21, p = 0.004 respectively from nonparametric tests) that persisted after adjusting for age, blood pressure variables, body mass index, ApoB/A1 ratio, smoking as well as cerebral pulsatility index, a previously suggested early marker of SVD. The gcPWV displayed satisfactory stability to field-of-view variations. Our results suggest that SVD is accompanied by changes in the cerebral arterial wall that can be captured by considering the velocity of the pulse wave transmission through the cerebral arterial network.
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| 30. |
- Bodin, Maja, 1984-
(författare)
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To Plan or Not to Plan : Gender Perspectives on Pregnancy Planning, Fertility Awareness and Preconception Health and Care
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The level of pregnancy planning is of importance to the well-being of parents and children. Unintended and/or unwanted pregnancies are often associated with less health promoting behavior during pregnancy, poorer health of the new born, and relationship dissatisfaction. Preconception care is a health service with the purpose to encourage people to become mindful about their reproductive intentions and raise fertility awareness, in order to maintain or improve reproductive health.Reproductive health is a highly gendered area, both due to biological conditions and social expectations on gender. In most cases, the focus of reproductive health and health promotion is on cis-women and their bodies. This thesis mainly focuses on persons self-identifying as men. The aim is to scrutinize the area of preconception health, investigate what pregnancy planning means to men and explore the relationship between pregnancy planning and fertility awareness.In Study I, 136 couples who attended their first antenatal visit answered questions about pregnancy planning. Most pregnancies were planned and couples had similar perceptions of the level of their planning. Study II describes pregnancy planning behavior and fertility knowledge among 796 recent fathers. Also in this study, most pregnancies were planned and 17% of the men had made at least one preconception lifestyle adjustment to improve health and fertility. Fertility knowledge varied greatly, although men with higher education demonstrated higher knowledge. Study III explores if Reproductive Life Plan-based counselling during a sexual health visit could increase men’s fertility awareness. The counselling had a moderate effect on participants’ fertility knowledge but managed to raise new thoughts about their own fertility, and was well received. Study IV follows up on the results from the first three studies, through in-depth interviews and focus group discussions with 25 men aged 23-49. Most participants took their fertility for granted. To cis-men in heterosexual relationships, the meaning of pregnancy planning usually meant taking the decision to try to become pregnant, and not much more. Trans-men and gay men where more invested in practical planning issues. In conclusion, this thesis shows how pregnancy planning is gendered, and that it is a more complex phenomenon than previously acknowledged.
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| 31. |
- Cristea, Alexander, 1966-
(författare)
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Effects of Ageing and Physical Activity on Regulation of Muscle Contraction
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aims of this study were to investigate the mechanisms underlying (1) the ageing-related motor handicap at the whole muscle, cellular, contractile protein and myonuclear levels; and (2) ageing-related differences in muscle adaptability.In vivo muscles function was studied in the knee extensors. Decreases were observed in isokinetic and isometric torque outputs in old age in the sedentary men and women and elite master sprinters. A 20-week long specific sprint and resistance training successfully improved the maximal isometric force and rate of force development in a subgroup of master sprinters.In vitro measurements were performed in muscle biopsies from the vastus lateralis muscle. Immunocytochemical and contractile measurements in single membrane permeabilized muscle fibres demonstrated ageing- and gender-related changes at the myofibrillar level. In sedentary subjects, data showed a preferential decrease in the size of muscle fibres expressing type IIa MyHC in men, lower force generating capacity in muscle fibres expressing the type I MyHC isoform in both men and women and lower maximum velocity of unloaded shortening (V0) in fibres expressing types I and IIa MyHC isoforms in both men and women. The master sprinters also experienced the typical ageing-related reduction in the size of fast-twitch fibres, a shift toward a slower MyHC isoform profile and a lower V0 of type I MyHC fibres, which played a role in the decline in explosive force production capacity. The fast-twitch fibre area increased after the resistance training period. A model combining single muscle fibre confocal microscopy with a novel algorithm for 3D imaging of myonuclei in single muscle fibre segments was introduced to study the spatial organisation of myonuclei and the size of individual myonuclear domains (MNDs). Significant changes in the MND size variability and myonuclear organization were observed in old age, irrespective gender and fibre type. Those changes may influence the local quantity of specific proteins per muscle fibre volume by decreased and/or local cooperativity of myonuclei in a gender and muscle fibre specific manner.In conclusion, the ageing-related impairments in in vivo muscle function were related to significant changes in morphology, contractile protein expression and regulation at the muscle fibre level. It is suggested that the altered myonuclear organisation observed in old age impacts on muscle fibre protein synthesis and degradation with consequences for the ageing-related changes in skeletal muscle structure and function. However, the improved muscle function in response to a 20-week intense physical training regime in highly motivated physically active old subjects demonstrates that all ageing-related in muscle function are not immutable.
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| 32. |
- Darmastuti, Zhafira
(författare)
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SiCFET gassensors : theory, developent, and applications to flue gas cleaning processes in power plants
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Environmental and health concerns lead to stricter regulations on power plant emission. Sensors play an important role, not only as part of the process control to ensure that the effluent stays under the regulated values, but also to increase the pollution removal efficiency and to decrease the reagent consumption.Previous studies, on the use of SiC based Field Effect Transistors (FET) as NH3 sensors in Tekniska Verken power plants and as CO sensors for the control of the domestic boilers, have shown promising results. Moreover, these sensors can withstand high temperature operation and are considerably cheaper than most conventional sensors used in power plants. The price of the sensors enable the installation of multiple sensors in one flue gas duct section, which lead to better monitoring of the flue gas uniformity. Based on that argument, this study is performed to determine whether it is possible to expand the possible application of SiC-FET sensors for the detection of other pollutants emitted by power plants. This thesis reports the characterization and performance testing of SiC-FET sensors towards other selected air pollutants: H2S, methanol as a product of CO2 hydrogenation, and SO2.The study is performed by I-V characterization of the sensors toward the test gas in different background gases and studies of the detection mechanism. Detection mechanism studies include DRIFT spectroscopy, mass spectroscopy, and theoretical study of the surface reaction with Density Functional Theory (DFT).Ir-gate SiC-FET sensors at 350oC show a very high sensitivity to H2S. The large response reduces the possibility of cross-sensitivity from other gases. Pt-gate sensors offer very fast response with decent response magnitude at 200oC for methanol. The presence of oxygen improves the response to methanol, which is favorable for the leak detection application. Besides oxygen, the influence of hydrogen, propene, and water vapor is also observed in the experiment with methanol. The detection mechanism and different sensing behavior of Pt and Ir gates are illustrated with model reaction mechanisms on the surface of the metals. Sensor characterization has been performed for SO2 with several catalytic metal gates: Pt, Ir, Cu, and Au. The results suggest that a single sensor with any of Pt, Ir, Cu, and Au gates is able to detect the presence of SO2 in the air or nitrogen background. However, they are unable to measure different SO2 concentration. Moreover, the response level to SO2 is so small, that it will probably disappear if there is any other gas present in the mixture.
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| 33. |
- Eklund, Magnus, 1976-
(författare)
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Adoption of the Innovation System Concept in Sweden
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In 2001 Sweden founded the government agency of VINNOVA, named after the OECD-endorsed innovation system concept. Criticising the common assumption that countries are passive and uncritical recipients of the approaches promoted by the OECD, this dissertation tries to show that Swedish actors were in fact very active and strategic as they contributed to the national adoption of the concept. With inspiration from conceptual history and Quentin Skinner’s analysis of the rhetorical use of concepts, this study focuses on the research funding reform process between 1995 and 2001, investigating how actors trying to defend the contested institution of sectoral research used the innovation system concept to rhetorically legitimise their project. To compare these uses with earlier ways of discussing innovation in Sweden, the innovation debate that arose in relation to the industrial crises of the 1970s and 1990s has also been studied. It was found that the early Swedish innovation debate had paid little attention to the university sector. When Research 2000 in 1998 proposed that researcher-dominated research councils should be given control over sectoral research funding, a coalition in favour of industrially relevant research mobilised to protect its influence over research funding. The concept was now appropriated and used to rhetorically reframe the universities as part of a system with the main function of promoting innovations. By using the concept it was also possible to draw on the legitimacy offered by the OECD and science.
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| 34. |
- Erlandsson, Johan
(författare)
-
CONTROLLED ASSEMBLY AND FUNCTIONALISATION OF CELLULOSE-BASED MATERIALS
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The environmental effects caused by the use of fossil-based resources have intensified and driven society and research towards new materials and processes that utilise renewable resources. Within the development of new materials, wood has been identified as a raw-material from which high performing materials can be derived. One such material is cellulose nanofibrils (CNFs) which are capable of replacing several currently used fossil-based materials. However, for CNFs to exhibit the required material properties they need to be chemically or physically modified. This means that the properties of the CNFs can be specifically adapted to fit the demand in particular areas, for example electrical energy storage. In these applications it is the mechanical properties; the large, easily functionalised surface and ability to be moulded into 3D shapes that make CNFs a highly interesting raw material.This thesis explores the formation and functionalisation of CNF- and fibre-based materials and their novel use in applications such as energy storage. The wet stability of the materials was achieved by crosslinking and ice templating the fibrils by a novel freezing procedure, which makes it possible to avoid the use of freeze-drying and subsequent crosslinking. Using colloidal probe atomic force microscopy adhesion measurements, hemiacetals were shown to be formed between the aldehyde-containing fibrils when they are brought into molecular contact, for example during ice templating. Hemiacetal crosslinked aerogels have been shaped and functionalised to demonstrate their application as biomimetic structural composites, electrical circuits and electrical cells. In addition, crosslinked, light-weight 3D fibre networks were prepared with á similar chemistry by a self-assembly process of pulp fibres. These networks could be dried under ambient conditions and the materials formed were wet-stable due to the hemiacetal crosslinks formed in the fibre–fibre contacts, which provided the networks with excellent mechanical properties and shape recovery capacity in water.Finally, using a newly developed polyampholyte and mixing it with CNFs, heterofunctional composite films and aerogels could be prepared. By activating crosslinkable groups in these composite materials, they were able to undergo further water based chemical functionalisation. In this highly dispersed state, the composite could be irreversibly crosslinked by a hydrothermal treatment to create transparent, low solid content hydrogels.
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| 35. |
- Faxälv, Lars, 1977-
(författare)
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Imaging methods for haemostasis research
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Blood is a vital part of the human physiology; a transport system that brings nutrients and oxygen to sustain living cells and simultaneously facilitates the removal of carbon dioxide and other waste products from the body. To assure the continuity of these functions, it is of uttermost importance to keep the flowing blood inside the vascular system at any cost. The principal components of the haemostatic system are the blood platelets and the plasma coagulation system, both working in concert to create a blood stopping haemostatic plug when a vessel is ruptured. In modern health care, methods for treatment and diagnostics often implicate the contact between blood and artificial materials (biomaterials). Biomaterial surfaces may activate platelets and the coagulation cascade by exposing a surface that during blood contact shares certain characteristics with surfaces found at the site of vascular injury. Therefore it is of great importance that the mechanisms behind the interactions between foreign surfaces and blood are studied in order to minimize, and if possible, prevent unnecessary reactions that may lead to thrombosis.This thesis describes two important methods to study blood – surface interactions in terms of surface induced plasma coagulation and platelet adhesion/aggregation. The method ‘Imaging of coagulation’, a coagulation assay based on time-lapse image capture of the coagulation process was developed during the course of this work. The use of images enables the method to answer questions regarding where coagulation was initiated and how fast coagulation propagates. Such questions are highly relevant in the study of blood-biomaterial interactions but also in general haemostasis research. In vivo, platelet adhesion and aggregation are events that always proceed under flow conditions. Therefore we also developed a cone-and-plate flow model to study these mechanisms under similar conditions in vitro. The cone-and-plate setup was found to be a flexible platform and was used for both blood compatibility testing of potential biomaterials as well as for general haemostasis research.With the above mentioned methods we tested the haemocompatibility of glycerol monooleate (GMO), a proposed substance for use in biomaterial applications. It was found that GMO did not activate coagulation to any great extent either in plasma or in whole blood.Surface induced coagulation and platelet adhesion was also studied on PEG-containing hydrogels and compared with hydrogels constructed from three different non-PEG-containing monomers. It was concluded that all the grafted hydrogels, in particular those produced from the monomers 2-hydroxyethyl methacrylate (HEMA) and/or PEG- methacrylate (PEGMA), demonstrated good haemocompatibility.Supported phospholipid bilayers were used to investigate the relationship between surface charge and procoagulant activity. The coagulation process was studied in a straightforward manner using the imaging of coagulation setup. We concluded that the content of negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-L-serine] (POPS) in the bilayer must exceed ~ 6% for the bilayer to exert procoagulant activity.The physiological role of factor XII in human haemostasis and thrombosis was investigated in the imaging of coagulation setup and the cone and plate setup by the use of surfaces with thrombogenic coatings. We found that tissue factor initiated coagulation could be greatly accelerated by the presence of contact activating agents in a platelet dependent manner.In conclusion, the method ‘Imaging of coagulation’ and platelet adhesion/aggregation in the cone-and-plate flow model are both versatile methods with many possible applications. The combination of the two methods provides a solid foundation for biomaterial and haemostasis research.
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| 36. |
- Görür, Yunus Can
(författare)
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Design of Cellulose-Based Materials via Sustainable and Scalable Processes
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Plastic pollution is one of the most pressing environmental issues in today’s world. Addressing this problem calls for the development of environmentally friendly alternatives that would reduce the amount of persistent plastic waste. Wood-based cellulose is an excellent candidate as a renewable and biodegradable alternative to oil-based plastics in a variety of applications. However, for their widespread adoption, cellulosic materials need to perform comparably to their oil-based counterparts, while simultaneously attaining similarly high processing efficiencies. A major challenge today is to produce high-performance cellulosic materials at industrially feasible rates using scalable methods. This thesis demonstrates that with a fundamental understanding of fiber chemistry and behavior, cellulose fibers can be tuned to develop sustainable material streams and advanced functional materials at high process rates. First, a new stimuli-responsive cellulosic fiber material called self-fibrillating fibers (SFFs) was developed, where the mechanisms governing the swelling of the fiber wall were thoroughly investigated. The knowledge and understanding obtained from these fundamental studies were utilized to prepare pH-responsive filters. Secondly, the preparation of SFF papers and nanopapers using conventional papermaking methods and equipment was demonstrated within the context of rapid transparent paper preparation. It was shown that SFFs can be rapidly dewatered to obtain papers, where the constituting fibers can be nanofibrillated in situ, resulting in strong, transparent and gas barrier nanopapers without sacrificing processing speed. Thirdly, the use of SFFs was extended to functional nanocomposites. A new and scalable materials processing platform for the rapid preparation of functional cellulose hybrids was developed. The stimuli-responsive self-assembly of chemically nanofibrillated SFFs was studied and utilized to prepare nanopapers and hybrid materials. Finally, SFFs were used as bio-based binders in the fabrication of graphitic Li-ion battery electrodes with improved processing and electrochemistry. Taking advantage of their facile nanofibrillation and favorable chemistry, SFFs were nanofibrillated during slurry mixing then blade-coated on copper supports to create strong electrodes with excellent performance.The novel materials and methodologies presented herein combine an aqueous fiber modification strategy with excellent processing properties for the preparation of high-performance cellulosic materials that can compete with oil-based plastics in various applications.
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| 37. |
- Hjalmarson, Jenny, 1974-
(författare)
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Ergonomics at Home : Design for Safe Living and Home Care
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The home should represent safety and security for the person who lives there, and this is an important factor for independence and autonomy in very old age. With aging populations, the needs for long-term care increase, care provided by spouses and/or from the growing home care sector. Injuries among these groups are common.In this study, an ergonomics perspective was applied in the analysis of some basic daily activities performed by old persons and by home care workers, assisting.The postures and movements of home care staff assisting at toilet visits, and transferring persons from wheelchair to toilet, were measured and analysed.Some daily activities related to making food and washing clothes, performed by a group of persons between the age of 75 and 100, were measured and analysed.The task of getting up from the floor – on your own and with the help of a walker equipped with a lifting device – was analysed with the help of older persons and nursing staff. The design was built on the knowledge gained from analysing how older people get up from floor.Requirements for access with a four-wheeled walker in the local built environment were investigated.Observations were made with the help of video recording. Postures were recorded with the CUELA measurement system. The VIDAR ergonomics evaluation instrument was used to register the participants’ experiences of discomfort and pain during getting up from the floor with or without the walker with a lifting device. Structured interviews were used to find out about older peoples’ experience of using the four-wheel walker.It is concluded that ageing at home requires improved architectural and technical bathroom design and improved access in the local built environment.
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| 38. |
- Jain, Karishma
(författare)
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Design of Cellulose-Based Electrically Conductive Composites: Fundamentals, Modifications, and Scale-up
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modern demand for consumer electronics is fueling the generation of 'E-waste.' Furthermore, theraw materials and manufacturing methods used in the fabrication of electronics are not sustainable.There is therefore the need to develop renewable and sustainable raw materials for electronicdevices that do not sacrifice performance; as well as a requirement to develop novel, scalable,sustainable electronic device fabrication methods that use these green electronic materials. To thisend, bio-based materials are an environment-friendly alternative to non-renewable materials; andprinted electronics could replace traditional manufacturing methods. Cellulose, one of the mostabundant biopolymers on Earth, exhibits an interesting hierarchical structure. Due to extensiveresearch over the years, there are a wide variety of established chemical modifications for cellulose,which can be harnessed to prepare high-performance electronic components. The hierarchicalstructure of cellulose is crucial in defining its material properties. In cellulose rich fibers, highmolecular mass glucan polymers are commonly found in the form of cellulose nanofibrils (CNFs);these can be liberated and, once so, are capable of self-assembling into a wide variety of structures.Since cellulose is electrically insulating, it needs to be made into composites with conductivematerials to form electrically conductive materials.This thesis investigates the interaction between cellulose and the conductive polymer PEDOT:PSS(poly(3,4-ethylenedioxythiophene) : polystyrene sulfonate), and demonstrates how a fundamentalunderstanding of the interactions between the two can be used to guide the chemical modificationof cellulose for the large scale production of sustainable electronics. First, the PEDOT:PSS structurewas studied using molecular dynamics (MD) simulations and experimental methods. Secondly, theinteraction between cellulose and PEDOT:PSS was studied, and factors affecting this interactionwere identified. This knowledge was then applied to propose a molecular interaction mechanismbetween these materials. Nanocellulose, especially cellulose nanofibrils (CNFs), have been integralto the development of bio-based conductive composites. However, the nanofibrillation process isexpensive and energy-intensive. In addition, PEDOT:PSS is an expensive polymer. Therefore, inthis work, chemically modified fibers were used to improve the interaction between cellulose andPEDOT:PSS; and prepare fiber-based bioelectronics and energy storage devices. The large-scaleproduction of papers capable of energy storage has also been demonstrated using chemicallymodifiedfibers, the factors affecting the processing of these materials have been identifiedthroughout.
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| 39. |
- Larsson, Anna, 1974-
(författare)
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Real Effects of Monetary Regimes
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of three essays on the real effects of monetary regimes.“Monetary Regimes, Labour Mobility and Equilibrium Employment” analyses the impact of the monetary regime on labour markets in a small open economy by considering the game between large wage setters and the central bank in a model with labour mobility between sectors. Two monetary regimes are considered: membership in a monetary union and a national inflation target. A key result is that when there is perfect labour mobility, the monetary regime is of no importance for real wages, employment or profits. When labour is immobile between sectors: (i) the real wage in the tradables sector is higher under inflation targeting than in a monetary union, while the reverse applies to the non-tradables sector; (ii) inflation targeting generates higher employment and profits than membership in a monetary union; and (iii) workers and firms in the two sectors in general prefer inflation targeting to membership in a monetary union.“Fiscal Activism under Inflation Targeting and Non-atomistic Wage Setting” considers a game between the government, an independent central bank and non-atomistic wage setters. I discuss the implications of inflation targeting and fiscal activism for the labour market outcome. The results suggest that while inflation targeting may discipline wage setters, activist fiscal policy generates higher real wages and lower employment. The main explanation is that unions make the government assume responsibility for some of the cost of high wages. The difference between regimes is greater if the government pursues activist fiscal policy, which suggests that inflation targeting is even more important in economies with a high degree of fiscal activism.“The Swedish Real Exchange Rate under Different Currency Regimes” presents evidence on the behaviour of the Swedish real exchange rate relative to Germany under different currency regimes 1973:1-2001:4. The results suggest that the real exchange rate is cointegrated with Swedish and German productivity, which is consistent with Balassa (1964) and Samuelson (1964). In the short run, the exchange rate regime has mattered for the dynamics of the real exchange rate. Deviations from long-run equilibrium have been adjusted more quickly when the nominal exchange rate has been allowed to float freely.
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| 40. |
- Larsson, Bengt, 1953-
(författare)
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Ungdomarna och idrotten : tonåringars idrottande i fyra skilda miljöer
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main aim of the study is to generate increased knowledge about young people’s leisure time sporting habits in a contextual perspective. The intention is to highlight the circumstances in which young people pursue and participate in different activities, with a particular focus on sport in terms of one’s own life circumstances. An essential point of departure of the study is regarding sport as an important pedagogic environment of norms and values.The perspective of the study is mainly cultural-sociological. In the analyses, Pierre Bourdieu’s key concepts habitus and capital have been used as research tools together with gender. The data on which the thesis is based is collected from young people from school year 9 living in four different milieus and comes from three different collections, conducted in 1996, 2002 and 2007. In each data collection about 1200-1500 pupils replied to a questionnaire.Sport occupies a central position in young people’s life on the recreational field. The results show that sport culture can best be understood in the local perspective. Young people’s sporting habit development can be said to be a result of a complex interplay between personal preferences, the home environment, local traditions, what is on offer, living conditions and the prevailing laws of gender and status.For the group of teenagers as a whole the proportion of members, as well as those who pursue personal sports, increases with higher educational capital and higher economic capital. When it comes to organised sport outside the sports club milieu no such connection can be determined.The thesis has shown that sport is not accessible for all and opportunities for participation are curtailed for large groups of young people in our society. This is especially true for sport organised in sport clubs, i.e. sport mainly supported by public funds.
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| 41. |
- Larsson, Cecilia M
(författare)
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Early Cambrian Problematic Lophotrochozoans and Dilemmas of Scleritome Reconstructions
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The emergence and radiation of metazoan body plans around the Precambrian/Cambrian boundary, some 500-600 million years ago, seems to be concordant with the appearance and diversification of preservable hard parts. Several Precambrian soft-bodied, multicellular organisms most likely represent stem-group bilaterians, but their fossil record is rather sparse. In contrast, the Cambrian fossil record is comparably rich – comprising hard part, trace fossil and delicate soft tissue preservation – and most animal phyla that we know of today had evolved by the end of the Cambrian. Consequently, this time represents an important period in the early evolution of metazoan life forms. Most skeletal remnants of invertebrate organisms from this period are preserved in incomplete, disarticulated sclerite assemblages, and the true architecture of the original skeletal structure, the scleritome, may therefore be hard to discern. Many scleritomous taxa have been suggested to be members of the lophotrochozoan clade, while their exact position within this group remains unclear. Such taxa are often referred to as Problematica. This thesis deals with some problematic scleritomous early Cambrian lophotrochozoans, and as such also addresses the dilemmas of scleritome reconstructions. In the first part, completely disarticulated calcareous sclerites from the lower Cambrian of North Greenland are described as Trachyplax arctica. Hypothetical scleritome reconstruction alternatives and comparisons to other scleritome-bearing taxa are discussed, but the lack of articulated material obscures any satisfactory conclusions regarding phylogenetic affinities and the original morphology of the organism. The other part of the thesis focuses on some minute, organophosphatic scleritomous metazoans, tommotiids, found in lower Cambrian limestone successions in South Australia – Paterimitra pyramidalis and Kulparina rostrata – their scleritome architecture and their phylogenetic relationship with paterinid brachiopods. The oldest brachiopod from South Australia, Askepasma saproconcha, and the slightly younger Askepasma toddense are also described and discussed. Based on articulated specimens, recently described partial scleritomes of the tommotiid Eccentrotheca helenia and similarities in shell ultrastructure with both Eccentrotheca and Askepasma, Paterimitra is interpreted as a stem-group brachiopod and reconstructed as a bilaterally symmetrical, sessile, filter feeder with a tubular/conical scleritome. The morphological similarities with Paterimitra point in the same direction for the slightly older Kulparina.
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| 42. |
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| 43. |
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| 44. |
- Larsson, Johan, 1979-
(författare)
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Leadership for Quality, Effectiveness and Health
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Leadership, quality, effectiveness and health are important factors in the achievement of organisational success. Three questions are addressed to study these elements: 1. How do leadership values relate to leadership behaviours, quality methodologies and health in organisations? 2. How do leadership behaviours relate to effectiveness and health in organisations? 3. How can leadership tools be designed and used to promote health in organisations? The research is based on five studies from three research projects. This research is reported in five papers. Study I concerned eight organisations in the middle of Sweden; the focus was on leadership values and behaviours. Study II concerned three successful organisations that received the award, ‘Sweden’s number one workplace’. Focus in this study was mainly on leadership behaviours. Study III combined results from Studies I and II with a focus on successful leadership behaviours. Study IV concerned the eight organisations in Study I. A leadership tool in the form of a Plan-Do-Study-Act (PDSA) model was developed and evaluated. Study V was of two organisations in Sweden; the focus in that work was on the use of a leadership tool control chart designed to give managers statistically valid early warning signals about health in their organisations. Theory X and Y together with the three-dimensional leadership behaviour theory were used to assess leadership values and behaviours. The theory surrounding PDSA and control charts were used to develop leadership tools. The dimension of health is defined from a salutogenic humanistic perspective; which emphasizes individual well-being. The dimension of quality is defined as the ability to satisfy or exceed needs and expectations. Effectiveness is defined as the extent to which externally and internally defined objectives are fulfilled. Both qualitative and quantitative research methods were used. Interviews, seminars with employees, collection of human resource and effectiveness figures, and questionnaires completed by managers and subordinates were used to collect data. Managers with more Theory Y-oriented leadership values were rated by subordinates as high concerning quality methodologies and leadership behaviour dimensions. The subordinates of these managers tended to be healthier. Two of the studies identified common groups of leadership behaviours in effective and healthy organisations: strategy and vision, communication and information, authority and responsibility, learning culture, worker conversations, plainness and simplicity, humanity and trust, walking around and reflective personal leadership. These leadership behaviours fit into a leadership profile where all three of the dimensions of structure, relation and change are present. Of the three, the relation dimension is strongest and concluded to be a universal dimension. The developed PDSA model seems to be a leadership tool that influences both leadership values and behaviour, particularly in the area of relation-oriented leadership behaviours. An early warning system built on CUSUM- and Shewhartcharts concerning the health indicators of self-assessed general health and new sickcases per employee was also found to be a powerful and usable leadership tool. For future research, the explorative research findings can be quantitatively tested using representative and preferably cross-national data, with a longitudinal design.
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| 45. |
- Larsson, Kjerstin, 1952-
(författare)
-
Quality of Life and Coping with Ulcerative colitis and Crohn's disease
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to investigate health-related quality of life (HRQoL) and coping strategies for individuals with ulcerative colitis (UC) or Crohn’s disease (CD), and to study the effect of a group-based patient information on anxiety/depression and HRQoL. HRQoL and anxiety/depression were investigated (n=492) (Study I). In Study II, anxiety/depression, HRQoL, satisfaction with information and evaluation of the patient information were studied (n=49). Coping with disease activity was investigated in 166 patients reporting current exacerbation (Study III). Fifteen patients were interviewed about disease-related stress, how this is managed and the need of support from the health care (Study IV). Patients with UC reported better HRQoL and less anxiety/depression than did patients with CD during both remission and exacerbation. Satisfaction with information had increased at follow-up 6 months after patient information. The information and the possibility to discuss with lecturers and group members were valued as most important. No change was found in anxiety/depression or HRQoL at follow-up. Both problem-focused and emotion-focused strategies were employed to cope with disease activity, with no difference between patients with UC or CD. The urgent need of toilet availability and stress associated to social situations were the major disease-related stressors. This stress was managed by finding out the location of toilets, bringing toilet paper and extra underwear and emptying bowel before an activity. The patients wanted information and possibilities to talk to experienced staff and to other patients about how to live with the disease. This thesis shows that HRQoL for some patients with UC, and primarily for patients with CD, is impaired. Thus medical staff should be observant of the psychosocial well-being of patients with CD and also of patients with relapse. Methods to identify and support patients with anxiety/depression and poor HRQoL need to be developed. Interventions should target the patient’s specific problems and at appropriate times.
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| 46. |
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| 47. |
- Larsson, Matilda, 1981-
(författare)
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Quantification and Visualization of Cardiovascular Function using Ultrasound
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is a large need for accurate methods detecting cardiovascular diseases, since they are one of the leading causes of mortality in the world, accounting for 29.3% of all deaths. Due to the complexity of the cardiovascular system, it is very challenging to develop methods for quantification of its function in order to diagnose, prevent and treat cardiovascular diseases. Ultrasound is a technique allowing for inexpensive, noninvasive imaging, but requires an experienced echocardiographer. Nowadays, methods like Tissue Doppler imaging (TDI) and Speckle tracking imaging (STI), measuring motion and deformation in the myocardium and the vessel walls, are getting more common in routine clinical practice, but without a proper visualization of the data provided by these methods, they are time-consuming and difficult to interpret. Thus, the general aim of this thesis was to develop novel ultrasound-based methods for accurate quantification and easily interpretable visualization of cardiovascular function. Five methods based on TDI and STI were developed in the present studies. The first study comprised development of a method for generation of bull’s-eye plots providing a color-coded two-dimensional visualization of myocardial longitudinal velocities. The second study proposed the state diagram of the heart as a new circular visualization tool for cardiac mechanics, including segmental color-coding of cardiac time intervals. The third study included development of a method describing the rotation pattern of the left ventricle by calculating rotation axes at different levels of the left ventricle throughout the cardiac cycle. In the fourth study, deformation data from the artery wall were tested as input to wave intensity analysis providing information of the ventricular – arterial interaction. The fifth study included an in-silico feasibility study to test the assessment of both radial and longitudinal strain in a kinematic model of the carotid artery. The studies showed promising results indicating that the methods have potential for the detection of different cardiovascular diseases and are feasible for use in the clinical setting. However, further development of the methods and both quantitative comparison of user dependency, accuracy and ease of use with other established methods evaluating cardiovascular function, as well as additional testing of the clinical potential in larger study populations, are needed.
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| 48. |
- Larsson, Markus, 1971-
(författare)
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Towards a Sustainable Food System : Entrepreneurship, Resilience and Agriculture in the Baltic Sea Region
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis compares conventional agriculture and Ecological Recycling Agriculture (ERA) in terms of their environmental and socio-economic effects. Environmental effects include greenhouse gas emissions and energy use, but this analysis focuses on nutrient losses. Socio-economic effects include production, costs and benefits at macro, firm and household level. Comparisons were made at regional (Baltic Sea), national (Swedish) and local (community/municipality) level. At regional level, the main challenge is to make agriculture more environmentally friendly and reduce nutrient losses, while maintaining food production. At national level, the challenges are to shift the product mix towards more vegetables and less meat and to address the geographical division between animal and crop production. At local level, the challenge is to achieve sustainable environmental, economic and social rural development. At regional level, the empirical findings were scaled up to create three scenarios. In one scenario, agriculture in Poland and the Baltic States was transformed to resemble the Swedish average structure and resource use, which gave increased nitrogen and phosphorus surplus and substantially increased food production. Two other scenarios in which agriculture in the entire Baltic Sea area converted to ERA gave reductions in nitrogen surplus and eliminated the phosphorus surplus, while food production decreased or remained stable, depending on the strategy chosen. At national level, the environmental effects of different production methods, transport and different food baskets were compared. A household survey was performed to construct an alternative food basket, which was high in vegetables, low in meat and high in locally produced organic food compared with the average Swedish food profile. It was also 24% more expensive. Food basket content was found to be as important as production method in reducing environmental effects. Local production and processing was less important. At local level, an importer and wholesaler of organic fruit and vegetables and a group of environmentally concerned consumers were studied. The business was found to be resilient, i.e. well-suited to adapt to turbulence, and with a history of being innovative.
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| 49. |
- Larsson, Per A., 1980-
(författare)
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Hygro- and hydroexpansion of paper : Influence of fibre-joint formation and fibre sorptivity
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Paper is a versatile, cheap and environment-friendly material. Nevertheless, there are several factors limiting its usefulness, and one of the major issues is that cellulosic and ligno-cellulosic fibres spontaneously sorb water. At the same time, the water uptake changes the dimensions of the paper. This phenomenon is usually referred to as a lack of dimensional stability and is often evident as misregister during multicolour printing, or curl, cockle and wavy edges during printing, copying, and storage, or, in a widerperspective, as a shortened lifetime of boxes during storage due to mechano-sorptivecreep. This thesis aims to improve the understanding of the mechanisms behind the dimensional(in)stability of paper. It looks beyond finding the best starting material and explores what can be done chemically to further improve the dimensional stability. Furthermore, it compares traditional hygroexpansion measurements, where the dimensional change is measured as a function of atmospheric relative humidity, and dimensional changes caused by liquid water, referred to here as hydroexpansion. The main parameters which have been studied are the ability of the fibres to join together and their ability to sorb water. In other words, how the degree of molecular contact within the fibre joints, as well as how the fibres are dried, affect the dimensional stability of the final paper, and whether it is possible to reduce the sorptivity of the fibres, and thus their ability to expand, by chemically cross-linking the fibre-wall. It was found that the degree of fibre-fibre contact, modified by drying or adsorption of polyelectrolyte multilayers, had little influence on the hygroexpansion or on the hydroexpansion if the sheets were dried under restraint, whereas freely dried sheets with a reduced degree of contact showed a slightly better dimensional stability, at least during hygroexpansion. What, however, had a positive effect on both hygro- and hydroexpansion was the fibre-wall cross-linking. In this work, cross-linking was achieved by oxidising the cellulose to dialdehydecellulose which can form cross-links with adjacent cellulose molecules, and thus reduce the rate of water diffusion into the fibre and hence the uptake of water. In the case of the most oxidised and cross-linked fibres, the diffusion coefficient was found to be 2–3 times lower than that of the non-oxidisedreference. The effect of the cross-linking was, however, the most prominent the first time the moisture content of the paper was increased since cycled samples no longer show this lower adsorption rate. It is suggested that this is due to the formation of a new pore system when the moisture content is increased, and the slow creation of this pore system reduces the moisture uptake of the sample. If hygroexpansion is compared with hydroexpansion, it is evident that a given change in moisture content does not correspond to the same absolute expansion, the maximum hydroexpansion being lower by a factor of 2–3 than the hygroexpansion of the same paper. This is probably because the applied liquid water is never equally distributed in the fibre network before it evaporates. Another effect of the more dynamic absorption of liquid water and the subsequent hydroexpansion is that at least in non-restrained samples there is first a rapid initial expansion which is followed 5 to 15 seconds later by a rapid in-plane contraction. It is suggested that this contraction is due to a combination of the release of dried-in strains, drying, and an increase in surface roughness.
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| 50. |
- Lind, Lars, et al.
(författare)
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On the association between body fat and left ventricular mass
- 2019
-
Ingår i: Journal of Hypertension. - 0263-6352 .- 1473-5598. ; 37:8, s. 1699-1704
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: As intervention studies have shown a reduction in body weight to be paralleled with a reduction in left ventricular mass (LVM), we quantified a hypothesized causal relationship between fat mass and LVM, and how much of these effects that was mediated by blood pressure (BP), diabetes and adipokines. Also visceral and subcutaneous adipose tissue (VAT and SAT) were explored in the same fashion.Methods: In the Prospective Study of the Vasculature in Uppsala Seniors study (n = 1016, 50% women, all aged 70 years), LVM was measured by echocardiography (indexed for lean mass, LVMI), fat and lean mass by dual-energy X-ray. VAT and SAT were measured by abdominal MRI (in n = 275).Results: In a structural equation model adjusting for sex, the total effect of fat mass on LVMI was large (standardized coefficient 0.280, P = 3.2 × 10−15, 95% confidence interval 0.210–0.349). Out of the total effect of fat mass on LVMI, 29.0% was mediated by BP and glucose (P = 2.4 × 10−12). The BP pathway was most important, mediating 24.4% of the total effect of fat mass on LVMI (P = 4.6 × 10−7), while the glucose pathway accounted for 4.6% (P = 0.033). The association of VAT with LVMI (0.202, P = 2.4 × 10−4) was slightly weaker than that of SAT with LVMI (0.283, P = 1.0 × 10−6). Of several measured adipokines, leptin was a significant mediator of the effect of fat mass on LVMI (P = 3.0 × 10−3).Conclusion: One-third of the hypothesized association between body fat and LVMI was mediated by BP and glucose in this population-based cohort. Leptin was also an important mediator. Visceral adipose tissue was not more closely related to LVMI than subcutaneous abdominal fat.
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