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  • 101401.
    Örtnäs, Anna
    Linköping University, Department of Educational Science (IUV).
    Elevers vardagsuppfattningar om tekniska system2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Elever ska enligt kursplanerna i teknik få förståelse för de tekniska system de möter i sitt dagliga liv. Genom att eleverna får kunskap om teknik i allmänhet och tekniska system i synnerhet får de möjlighet att påverka sina liv som medborgare i en demokrati. I litteraturen saknas idag studier om elevers uppfattningar om tekniska system. Syftet med detta examensarbete är därför att studera vilka vardagsuppfattningar elever har om de tekniska system de möter i vardagen. Studien utgår från systemteori vilken ger en möjlighet att utnyttja det gemensamma mönster som kännetecknar analys av system. Genom enskilda intervjuer har jag studerat hur elever i år 8 och år 2 på gymnasiet uppfattar tekniska system, såsom mobiltelefonsystemet, tvättmaskinen och aluminiumburkens system. Vid intervjuerna användes tankestöttor, d v s föremål och bilder som anknyter till de tekniska systemen, vilket inspirerats av studier om begreppsuppfattning inom naturvetenskapen. Som ett komplement till samtalet uppmanades informanterna att skissa sin förståelse av systemen på papper. Resultaten visar att eleverna på högstadiet och gymnasiet har god kunskap om de tekniska systemen i denna studie. Informanterna har förmågan att se systemens struktur med delsystem. De visar kunskap om sambanden mellan människa och teknik och människans olika roller. Studien har givit mig värdefulla kunskaper om elevernas vardagsuppfattningar om tekniska system vilket ger mig möjlighet att lägga upp min framtida undervisning med utgångspunkt i deras konkreta erfarenheter av teknik i vardagen.

  • 101402.
    Örtqvist, Eva
    et al.
    Astrid Lindgrens Barnsjukhus Stockholm.
    Ludvigsson, Johnny
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Pediatrics. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Åman, Jan
    Barnkliniken Universitetssjukhuset, Örebro.
    Johansson, Calle
    Barnkliniken Ryhovs sjukhus, Jönköping.
    Karlsson, Anders
    Medicinkliniken Akademiska sjukhuset, Uppsala.
    Forsander, Gun
    Barnkliniken Lasarettet, Falun.
    Lindgren, Fredrik
    Sachsska Barnsjukhuset Stockholm.
    Persson, Bengt
    Astrid Lindgrens Barnsjukhus Stockholm.
    Berglund, Lars
    Clinical Research Centre Uppsala Universitet.
    Berne, Christian
    Medicinkliniken Akademiska sjukhuset, Uppsala.
    Bengtsson, Mats
    Klinisk Immunologi Uppsala Universitet.
    Björk, Elisabeth
    Medicinkliniken Akademiska sjukhuset, Uppsala.
    Wallensteen, Måna
    Astrid Lindgrens Barnsjukhus Stockholm.
    Temporary preservation of β-cell function by diazoxide treatment in childhood type 1 diabetes2004In: Diabetes Care, ISSN 0149-5992, E-ISSN 1935-5548, Vol. 27, no 9, p. 2191-2197Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE - We examined the effect of diazoxide, an ATP-sensitive K + channel opener and inhibitor of insulin secretion, on β-cell function and remission in children at clinical onset of type 1 diabetes. RESEARCH DESIGN AND METHODS - A total of 56 subjects (21 girls and 35 boys, age 7-17 years) were randomized to 3 months of active treatment (diazoxide 5-7.5 mg/kg in divided doses) or placebo in addition to multiple daily insulin injections and were followed for 2 years. RESULTS - Diazoxide decreased circulating C-peptide concentrations by ∼50%. After cessation of the treatment, basal and meal-stimulated C-peptide concentrations increased to a maximum at 6 months, followed by a decline. Meal-stimulated C-peptide concentration was significantly higher at 12 months (0.43 ± 0.22 vs. 0.31 ± 0.26 nmol/l, P = 0.018) and tended to fall less from clinical onset to 24 months in the diazoxide- vs. Placebo-treated patients (-0.05 ± 0.24 vs. -0.18 ± 0.26 nmol/l, P = 0.064). At 24 months, the meal-stimulated C-peptide concentrations were 0.24 ± 0.20 and 0.20 ± 0.17 nmol/l, respectively. Side effects of diazoxide were prevalent. CONCLUSIONS - This study demonstrates that partial inhibition of insulin secretion for 3 months at onset of childhood type 1 diabetes suspends the period of remission and temporarily preserves residual insulin production. Further evaluation of the full potential of β-cell rest will require compounds with less side effects as well as protocols optimized for sustained secretory arrest.

  • 101403.
    Örtqvist, Å.
    et al.
    Karolinska Institute, Danderyd Hospital, Stockholm, Sweden.
    Valtonen, M.
    University Central Hospital, Helsinki, Finland.
    Cars, O.
    Uppsala University, Sweden.
    Wahl, M.
    Östra Hospital, Göteborg University, Sweden.
    Saikku, P.
    University of Oulu and National Public Health Institute, Finland.
    Jean, C.
    Rhone DPC Europe, Paris, France.
    Augustinsson (Nilsdotter-Augustinsson), Åsa
    Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Oral empiric treatment of community-acquired pneumonia: A multicenter, double-blind, randomized study comparing sparfloxacin with roxithromycin. The Scandinavian Sparfloxacin Study Group1996In: Chest, ISSN 0012-3692, E-ISSN 1931-3543, Vol. 110, no 6, p. 1499-1506Article in journal (Refereed)
    Abstract [en]

    STUDY OBJECTIVE:

    Comparison of efficacy and safety of sparfloxacin (Spfx) vs roxithromycin (ROXI) for treatment of community-acquired pneumonia (CAP).

    DESIGN:

    Multicenter, double-blind, randomized study.

    SETTING:

    Twenty-three university and community hospitals in Scandinavia.

    PATIENTS:

    Three hundred four adults (> or = 18 years of age) with CAP treated as outpatients (25%) or inpatients (75%).

    INTERVENTIONS:

    Randomization 1:1 to Spfx, 400 mg on day 1, then 200 mg once daily, or ROXI, 150 mg twice daily, 10 to 14 days. Safety and efficacy analyses in intention-to-treat (ITT) and evaluable populations.

    RESULTS:

    Three hundred three of 304 patients were included in the ITT and safety analyses and 260 (86%) were evaluable at the end of follow-up. Streptococcus pneumoniae was the cause of pneumonia in 62 (20%) patients (11 with bacteremia), Chlamydia pneumoniae in 40 (13%), and Mycoplasma pneumoniae in 38 (13%) patients. The success rates for Spfx and ROXI at the end of follow-up were 82% and 72%, respectively, in the ITT population, and 94% and 79%, respectively, in the evaluable population. The odds ratio Spfx/ROXI for success was 4.5 (95% confidence interval, 1.9, 10.8) for the evaluable population. Both drugs were, overall, equally safe. GI symptoms were the most common adverse experiences in both groups. Prolongation of QTc, without clinical symptoms, was seen in 3% of Spfx patients and in 1% of ROXI patients, and photosensitivity, mostly mild to moderate, was seen in 5% of the Spfx group.

    CONCLUSIONS:

    Oral treatment with Spfx was superior to ROXI for the treatment of moderately severe CAP. Spfx was effective for all isolated pathogens, including S pneumoniae, and may be an alternative for empiric treatment of CAP, especially in areas with a high incidence of beta-lactam-resistant pneumococci.

  • 101404.
    Örulv, Linda
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Medical and Health Sciences, Health and Society.
    Demens: diagnosen som utmanar våra rädslor och fördomar2011In: Diagnos & identitet / [ed] Georg Drakos, Lars-Christer Hydén, Stockholm: Gothia Förlag AB, 2011, p. 100-129Chapter in book (Other academic)
  • 101405.
    Örulv, Linda
    Linköping University, Department of Medical and Health Sciences, Health and Society. Linköping University, Faculty of Arts and Sciences.
    Fragile identities, patched-up worlds: Dementia and meaning-making in social interaction2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on the identity work and the meaning- or sense-making that continue in the face of evolving dementia diseases, in social interaction, and the challenges for care this involves. The study adopts an actor-oriented approach and addresses the question of how persons with age-related progressive dementia diseases in everyday communication make sense of their situations, their surroundings, and their lives – all within the context of daily life in residential care. Of particular interest is how these persons handle issues of joint action in a shared world and how they establish and maintain an identity in the inte-raction. This is in spite of severe memory problems, disorientation in time and space, dif-fering understandings of the current situation, and difficulties in telling “accurate” and temporally ordered stories about their lives. The thesis also addresses the question of how caregivers may handle the complex interplay between residents in daily care, in maintain-ing and respecting these persons’ dignity.

    The study follows a growing tradition of studying interaction in dementia as mean-ing-based and situated in a context rather than merely as behavior caused by cognitive impairment. Methodologically, this is an ethnographic study based on observations made within a period of six months. The data consist of around 150 hours of video recordings and complementary field notes. This extensive material has made it possible to study the social interaction both in detail and situated in a larger context.

    The findings point to remaining competences and strategies that persons with demen-tia use actively and creatively in the ongoing interaction – and, given the premises, often in a rational way. This is discussed in terms of resources for dementia care, in relation to the great challenge of patching up and putting together a comprehensive socially shared world as well as maintaining continuity with the persons’ previous life histories in a way that preserves a positive self-identity.

    List of papers
    1. Confabulation: sense-making, self-making and world-making in dementia
    Open this publication in new window or tab >>Confabulation: sense-making, self-making and world-making in dementia
    2006 (English)In: Discourse Studies, ISSN 1461-4456, Vol. 8, no 5, p. 647-673Article in journal (Refereed) Published
    Abstract [en]

    This study is concerned with the productive aspects of confabulation as it occurs spontaneously in dementia care, in its context, and in interaction with other care recipients. Confabulation is approached as a social and discursive event with distinct narrative features; plots and formerly established genres of plots, storylines, are used by confabulators in order to understand, manage and interact socially in the present situation. Three main functions of confabulation are discerned: 1) making sense of the current situation (sense-making); 2) maintaining a personal identity in interaction with others (self-making); and 3) organizing and legitimizing joint action in the world (world-making). The resources used by confabulating subjects are sparse and not well adjusted to changing conditions, as the number of accessible storylines is limited. This makes it difficult to apply storylines that explain the current situation satisfactorily, provide useful guidelines for how to act, as well as preserve a positive self-identity. Helping with this constitutes a major challenge in dementia care.

    Keywords
    Alzheimer’s disease, communication, confabulation, context, dementiam, ethnography
    National Category
    Communication Studies
    Identifiers
    urn:nbn:se:liu:diva-13251 (URN)10.1177/1461445606067333 (DOI)
    Available from: 2008-05-06 Created: 2008-05-06 Last updated: 2013-09-04
    2. Placing the place, and placing oneself within it: (dis)orientation and (dis)continuity in dementia
    Open this publication in new window or tab >>Placing the place, and placing oneself within it: (dis)orientation and (dis)continuity in dementia
    2010 (English)In: Dementia, ISSN 1471-3012, E-ISSN 1741-2684, Vol. 9, p. 21-44Article in journal (Refereed) Published
    Abstract [en]

    Disorientation as experienced by persons with progressive dementia diseases involves both existential and social dimensions. Based on video observations from a small residential care unit and exploring social interaction on a micro-level, this case study focuses on how a woman with vascular dementia actively tries to make sense of an everyday lunch situation. The analysis addresses strategies used by her to contextualize where she has ended up, and also how the meaning of the place is altered in communication. Findings point to social interaction between residents as an important resource to help maintain continuity with previous social life. However, there also seems to be an impending need for caregivers to help residents patch up their broken life-stories to render everyday situations comprehensible and the setting socially meaningful. Helping them find a way of placing themselves within it — also affording a positive self-identity and continuity with previous life history — is a major challenge in daily care.

    Place, publisher, year, edition, pages
    Sage Publications, 2010
    National Category
    Social Sciences
    Identifiers
    urn:nbn:se:liu:diva-13252 (URN)10.1177/1471301210364449 (DOI)
    Available from: 2008-05-06 Created: 2008-05-06 Last updated: 2017-12-13Bibliographically approved
    3. Narrative and identity in Alzheimer’s disease: a case study
    Open this publication in new window or tab >>Narrative and identity in Alzheimer’s disease: a case study
    2009 (English)In: Journal of Aging Studies, ISSN 0890-4065, E-ISSN 1879-193X, Vol. 23, no 4, p. 205-214Article in journal (Refereed) Published
    Abstract [en]

    In this case study, focus is on how persons with AD use their remaining linguistic and cognitive resources, together with non-verbal aspects of the storytelling event, as resources in communicating and negotiating their identities in everyday encounters. The results of the analysis, focusing on the telling of the stories, indicate that other aspects than the temporal and referential organization of the narratives has become important resources for the teller in establishing and negotiating identity. The telling of temporally discontinuous narratives does not appear to affect or disrupt the teller's experience of some sort of a continuous sense of self and identity but are probably more a problem to persons without this kind of diagnosis. Being afflicted by AD most likely leads persons to try to invent and use alternative communicative recourses in order to sustain factors like their senses of self and identities. For researchers this makes it important to try to base their analysis on the actual organization of the talk and to focus on the functions of various responses and utterances in the interaction.

    Keywords
    identity, narrative, Alzheimer’s disease, performance, story-telling
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13253 (URN)10.1016/j.jaging.2008.01.001 (DOI)
    Available from: 2008-05-06 Created: 2008-05-06 Last updated: 2017-12-13
    4. Dignity work in dementia care: Sketching a microethical analysis
    Open this publication in new window or tab >>Dignity work in dementia care: Sketching a microethical analysis
    2007 (English)In: Dementia: the International Journal of Social Research and Practice, ISSN 1471-3012, Vol. 6, no 4, p. 507-525Article in journal (Refereed) Published
    Abstract [en]

    This study is concerned with issues of dignity in dementia care, in situations where staff members handle potential or actual conflicts and interaction problems between residents. Based on empirical data consisting of observations and video recordings, various coping strategies are identified in regard to whether or not, as well as when and how to interfere. Microethical analysis is used in order to discuss these coping strategies in relation to contextual conditions and ways of understanding, and values or aspects of dignity are highlighted. In dialogue with empirical data, nuances of ethical considerations are approached that are otherwise difficult to access analytically — thereby opening the door to a more reflective way of dealing with problematic situations in dementia care.

    Keywords
    coping strategies • conflict solving • ethics • ethnography • microethics
    National Category
    Social Sciences
    Identifiers
    urn:nbn:se:liu:diva-13254 (URN)10.1177/1471301207084368 (DOI)
    Available from: 2008-05-06 Created: 2008-05-06 Last updated: 2009-03-09Bibliographically approved
  • 101406.
    Örulv, Linda
    Linköping University, Department of Medical and Health Sciences, Health and Society. Linköping University, Faculty of Health Sciences.
    Placing the place, and placing oneself within it: (dis)orientation and (dis)continuity in dementia2010In: Dementia, ISSN 1471-3012, E-ISSN 1741-2684, Vol. 9, p. 21-44Article in journal (Refereed)
    Abstract [en]

    Disorientation as experienced by persons with progressive dementia diseases involves both existential and social dimensions. Based on video observations from a small residential care unit and exploring social interaction on a micro-level, this case study focuses on how a woman with vascular dementia actively tries to make sense of an everyday lunch situation. The analysis addresses strategies used by her to contextualize where she has ended up, and also how the meaning of the place is altered in communication. Findings point to social interaction between residents as an important resource to help maintain continuity with previous social life. However, there also seems to be an impending need for caregivers to help residents patch up their broken life-stories to render everyday situations comprehensible and the setting socially meaningful. Helping them find a way of placing themselves within it — also affording a positive self-identity and continuity with previous life history — is a major challenge in daily care.

  • 101407.
    Örulv, Linda
    Linköping University, Department of Medical and Health Sciences, Health and Society. Linköping University, Faculty of Arts and Sciences.
    Reframing dementia in Swedish self-help group conversations: Constructing citizenship2012In: International journal of self help & self care, ISSN 1091-2851, E-ISSN 1541-4450, Vol. 6, no 1, p. 9-41Article in journal (Refereed)
    Abstract [en]

    This study explores on a micro-level the activity of a self-help group for persons with dementia in Swedish municipal care, based on audio-recordings from 18 months' ethnographic fieldwork. The study focuses on the discursive construction of a shared meaning perspective and its inherent possibilities for liberation. Applying a citizenship perspective, the study approaches people with dementia as vulnerable to marginalization while at the same time capable of agency within the boundaries of their condition. The findings paint a complex picture involving opportunities and limitations of experiential knowledge, issues of double stigmatization, and constructs of being interrelated with other people and with the surrounding society. In the center is the overarching struggle of retaining citizenship in the face of the evolving disease.

  • 101408.
    Örulv, Linda
    Linköping University, Department of Social and Welfare Studies, NISAL - National Institute for the Study of Ageing and Later Life. Linköping University, Faculty of Arts and Sciences.
    Självhjälpsgrupper, nätverk och aktivism2016In: Att leva med demens / [ed] Ingrid Hellström, Lars-Christer Hydén, Malmö: Gleerups Utbildning AB, 2016, 1, p. 203-211Chapter in book (Other academic)
  • 101409.
    Örulv, Linda
    Linköping University, Department of Medical and Health Sciences, Health and Society. Linköping University, Faculty of Arts and Sciences.
    The subjectivity of disorientation: moral stakes and concerns2014In: Beyond Loss: dementia, identity, personhood / [ed] Lars-Christer Hydén, Hilde Lindemann, and Jens Brockmeier, Oxford: Oxford University Press, 2014, p. 191-207Chapter in book (Refereed)
    Abstract [en]

    This collection of interdisciplinary essays by international researchers tries to see beyond the loss in dementia, exploring it as transformation and change of personhood and identity that typically is embedded in social life. The chapters identify three important themes: persons and personhood, identity and agency, and the social and the communal.

  • 101410.
    Örulv, Linda
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute, Department of Communications Studies.
    Where are we? What's going to happen? Spontaneous narrating and dementia (presentation baserad på artikelarbete tillsammans med Lars-Christer Hydén)2003In: First Interdisciplinary Conference on Communication, Medicine Ethics COMET, 26-28 June 2003,2003, 2003Conference paper (Other academic)
    Abstract [en]

      

  • 101411.
    Örulv, Linda
    et al.
    Linköping University, Department of Medicine and Health Sciences, Health and Society. Linköping University, Faculty of Arts and Sciences.
    Hydén, Lars-Christer
    Linköping University, Department of Medicine and Health Sciences, Health and Society. Linköping University, Faculty of Arts and Sciences.
    Confabulation: sense-making, self-making and world-making in dementia2006In: Discourse Studies, ISSN 1461-4456, Vol. 8, no 5, p. 647-673Article in journal (Refereed)
    Abstract [en]

    This study is concerned with the productive aspects of confabulation as it occurs spontaneously in dementia care, in its context, and in interaction with other care recipients. Confabulation is approached as a social and discursive event with distinct narrative features; plots and formerly established genres of plots, storylines, are used by confabulators in order to understand, manage and interact socially in the present situation. Three main functions of confabulation are discerned: 1) making sense of the current situation (sense-making); 2) maintaining a personal identity in interaction with others (self-making); and 3) organizing and legitimizing joint action in the world (world-making). The resources used by confabulating subjects are sparse and not well adjusted to changing conditions, as the number of accessible storylines is limited. This makes it difficult to apply storylines that explain the current situation satisfactorily, provide useful guidelines for how to act, as well as preserve a positive self-identity. Helping with this constitutes a major challenge in dementia care.

  • 101412.
    Örulv, Linda
    et al.
    Linköping University, Department of Medicine and Health Sciences, Health and Society. Linköping University, Faculty of Arts and Sciences.
    Nikku, Nina
    Linköping University, Department of Behavioural Sciences and Learning, Sociology . Linköping University, Faculty of Arts and Sciences.
    Dignity work in dementia care: Sketching a microethical analysis2007In: Dementia: the International Journal of Social Research and Practice, ISSN 1471-3012, Vol. 6, no 4, p. 507-525Article in journal (Refereed)
    Abstract [en]

    This study is concerned with issues of dignity in dementia care, in situations where staff members handle potential or actual conflicts and interaction problems between residents. Based on empirical data consisting of observations and video recordings, various coping strategies are identified in regard to whether or not, as well as when and how to interfere. Microethical analysis is used in order to discuss these coping strategies in relation to contextual conditions and ways of understanding, and values or aspects of dignity are highlighted. In dialogue with empirical data, nuances of ethical considerations are approached that are otherwise difficult to access analytically — thereby opening the door to a more reflective way of dealing with problematic situations in dementia care.

  • 101413.
    Örulv, Linda
    et al.
    Linköping University, Department of Social and Welfare Studies, NISAL - National Institute for the Study of Ageing and Later Life. Linköping University, Faculty of Arts and Sciences.
    Strandroos, Lisa
    Linköping University, Department of Social and Welfare Studies, NISAL - National Institute for the Study of Ageing and Later Life. Linköping University, Faculty of Arts and Sciences.
    Vardagsdraman på det särskilda boendet2016In: Att leva med demens / [ed] Ingrid Hellström, Lars-Christer Hydén, Malmö: Gleerups Utbildning AB, 2016, 1, p. 79-86Chapter in book (Other academic)
  • 101414.
    Öst, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lipid Metabolism andInsulin Signalling in Adipocytes: enhanced autophagy in type 2 diabetes2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Energy storage in the adipose tissue, to an extent leading to obesity, is associated with local as well assystemic insulin resistance. When insulin-producing beta-cells in the pancreas gradually fail tocompensate, plasma levels of glucose rise and overt type 2 diabetes is diagnosed. Adipocytes are largecells, mostly consisting of one big central lipid droplet, with the surrounding plasma membrane full ofsmall invaginations called caveolae. As caveolae contain the insulin receptor and several other insulinsignallingproteins, we have investigated several aspects of caveolae. We have also mapped mechanismsand defects in the insulin-signalling network in adipocytes from type 2 diabetic patients.

    In paper I, we show that a subtype of caveolae has the capability to synthesize triglycerides from fattyacids and glycerol-3-phosphate. The triglyceride-synthesizing caveolae subtype also contains perilipin,suggesting the existence of a mechanism to protect newly made triglycerides from hydrolysis.

    In paper II, we demonstrate that adipocytes from patients with type 2 diabetes have an attenuated insulinstimulatedphosphorylation of IRS-1 at Ser-307 (human sequence), which correlates with reduced insulinstimulatedphosphorylation of IRS-1 at tyrosine residues. Insulin-stimulated phosphorylation of IRS-1 atSer-307 is dependent on the nutrient sensor TORC1. This finding indicates that adipocytes from type 2diabetic patients have reduced TORC1 activity.

    In paper III, we focus on the mechanisms for RBP4-induced insulin resistance. We also continue ourmapping of insulin-resistance in adipocytes from type 2 diabetes. These cells exhibit, in addition toimpaired insulin-stimulated glucose uptake and the defects presented in paper I, impaired insulinstimulatedphosphorylation of ERK. We do, however, not see any defects in PKB signalling. Neither dowe se any enhanced insulin-stimulated phosphorylation of IRS-1 at Ser-312 (human sequence), a site thatin mice is hyper-stimulated in response to high-fat feeding. Incubation with RBP4 recapitulates all defectswe so far have seen in type 2 diabetes except reduced insulin-stimulated glucose uptake. These results aremirrored by blockade of endogenously produced RBP4 in the incubations with adipocytes from type 2diabetic patients. In other words, RBP4-blocking antibodies restore all insulin-signalling defects we havefound in adipocytes from type 2 diabetic patients, except insulin-stimulated glucose uptake.

    In paper IV we show by several approaches that TORC1 activation is down-regulated in adipocytes fromtype 2 diabetic patients. The main finding is that there is enhanced autophagy in those adipocytes.Interestingly, autophagy may be a mechanism to enhance the breakdown of stored triglycerides in theadipocyte.

    In conclusion, our data suggest that caveolae, in addition to being micro-domains for insulin-signallingare metabolic platforms. We describe defects in insulin-signalling in adipocytes from type 2 diabeticpatients where the main finding is enhanced autophagy in these obese patients. The perceived starvationin adipose tissue might via secretion of adipokines, such as RBP4, have implications for local as well assystemic insulin-resistance.

    List of papers
    1. Triacylglycerol is synthesized in a specific subclass of caveolae in primary adipocytes
    Open this publication in new window or tab >>Triacylglycerol is synthesized in a specific subclass of caveolae in primary adipocytes
    Show others...
    2005 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 280, no 1, p. 5-8Article in journal (Refereed) Published
    Abstract [en]

    A principal metabolic function of adipocytes is to synthesize triacylglycerol (TG) from exogenous fatty acids. The level of fatty acids has to be tightly controlled in the adipocyte, as they can act as detergents that rapidly dissolve the plasma membrane, causing cell lysis if allowed to accumulate. Fatty acids therefore have to be efficiently converted to TG and stored in the central lipid droplet. We report that in intact primary adipocytes exogenous oleic acid was taken up and directly converted to TG in the plasma membrane, in a novel subclass of caveolae that specifically contains the protein perilipin. Isolated caveolae catalyzed de novo TG synthesis from oleic acid and glycerol 3-phosphate. Electron microscopy revealed the presence of caveolin and perilipin in caveolae and in lipid-laden bulbs in the plasma membrane, and fluorescence microscopy demonstrated colocalization of fatty acids/TG with caveolin and perilipin at the plasma membrane. A second caveolae fraction was isolated, which lacked perilipin and the triacylglycerol synthesizing enzymes. Both caveolae fractions contained caveolin-1 and the insulin receptor. The findings demonstrate that specific subclasses of caveolae carry out specific functions in cell metabolism. In particular, triacylglycerol is synthesized at the site of fatty acid entry in one of these caveolae classes.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-20650 (URN)10.1074/jbc.C400429200 (DOI)15537657 (PubMedID)
    Available from: 2009-09-16 Created: 2009-09-16 Last updated: 2017-12-13Bibliographically approved
    2. Attenuation of insulin-stimulated insulin receptor substrate-1 serine 307 phosphorylation in insulin resistance of type 2 diabetes
    Open this publication in new window or tab >>Attenuation of insulin-stimulated insulin receptor substrate-1 serine 307 phosphorylation in insulin resistance of type 2 diabetes
    2005 (English)In: Journal of biological chemistry, ISSN 0021-9258, Vol. 280, no 41, p. 34389-3492Article in journal (Refereed) Published
    Abstract [en]

    Insulin resistance is a primary characteristic of type 2 diabetes and likely causally related to the pathogenesis of the disease. It is a result of defects in signal transduction from the cell surface receptor of insulin to target effects. We found that insulin-stimulated phosphorylation of serine 307 (corresponding to serine 302 in the murine sequence) in the immediate downstream mediator protein of the insulin receptor, insulin receptor substrate-1 (IRS1), is required for efficient insulin signaling and that this phosphorylation is attenuated in adipocytes from patients with type 2 diabetes. Inhibition of serine 307 phosphorylation by rapamycin mimicked type 2 diabetes and reduced the sensitivity of IRS1 tyrosine phosphorylation in response to insulin, while stimulation of the phosphorylation by okadaic acid, in cells from patients with type 2 diabetes, rescued cells from insulin resistance. EC50 for insulin-stimulated phosphorylation of serine 307 was about 0.2 nM with a t1/2 of about 2 min. The amount of IRS1 was similar in cells from non-diabetic and diabetic subjects. These findings identify a molecular mechanism for insulin resistance in non-selected patients with type 2 diabetes.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-12791 (URN)10.1074/jbc.C500230200 (DOI)
    Available from: 2007-11-23 Created: 2007-11-23 Last updated: 2013-09-10Bibliographically approved
    3. Retinol-binding protein-4 attenuates insulin-induced phosphorylation of IRS1 and ERK1/2 in primary human adipocytes
    Open this publication in new window or tab >>Retinol-binding protein-4 attenuates insulin-induced phosphorylation of IRS1 and ERK1/2 in primary human adipocytes
    Show others...
    2007 (English)In: The FASEB journal : official publication of the Federation of American Societies for Experimental Biology, ISSN 1530-6860, Vol. 21, no 13, p. 3696-3704Article in journal (Refereed) Published
    Abstract [en]

    Reduced sensitivity to insulin in adipose, muscle, and liver tissues is a hallmark of type 2 diabetes. Animal models and patients with type 2 diabetes exhibit elevated levels of circulating retinol-binding protein (RBP4), and RBP4 can induce insulin resistance in mice. However, little is known about how RBP4 affects insulin signaling. We examined the mechanisms of action of RBP4 in primary human adipocytes. RBP4-treated adipocytes exhibited the same molecular defects in insulin signaling, via IRS1 to MAP kinase, as in adipocytes from patients with type 2 diabetes. Without affecting autophosphorylation of the insulin receptor, RBP4 blocked the insulin-stimulated phosphorylation of IRS1 at serine (307) [corresponding to serine (302) in the murine sequence] and concomitantly increased the EC50 (from 0.5 to 2 nM) for insulin stimulation of IRS1 phosphorylation at tyrosine. The phosphorylation of IRS1 at serine (312) [corresponding to serine (307) in the murine sequence] was not affected in cells from diabetic patients and was also not affected by RBP4. The EC50 for insulin stimulation of downstream phosphorylation of MAP kinase ERK1/2 was increased (from 0.2 to 0.8 nM) by RBP4. We show that ERK1/2 phosphorylation is similarly impaired in adipocytes from patients with type 2 diabetes. However, the sensitivity to insulin for downstream signaling to control of protein kinase B and glucose uptake was not affected by RBP4. When insulin-resistant adipocytes from patients with type 2 diabetes were incubated with antibodies against RBP4, insulin-induced phosphorylation of IRS1 at serine (307) was normalized and the EC50 for insulin stimulation of ERK1/2 phosphorylation was reduced. Endogenous levels of RBP4 were markedly reduced in adipocytes from obese or type 2 diabetic subjects, whereas expression levels of RBP4 mRNA were unaffected. These findings indicate that RBP4 may be released from diabetic adipocytes and act locally to inhibit phosphorylation of IRS1 at serine (307), a phosphorylation site that may integrate nutrient sensing with insulin signaling.

    Keywords
    Insulin resistance, type 2 diabetes, adipokine, protein phosphorylation, MAP kinase
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-20654 (URN)10.1096/fj.07-8173com (DOI)17575262 (PubMedID)
    Available from: 2009-09-16 Created: 2009-09-16 Last updated: 2013-09-10Bibliographically approved
    4. Attenuated mTOR signaling and enhanced autophagy in adipocytes from obese patients with type 2 diabetes
    Open this publication in new window or tab >>Attenuated mTOR signaling and enhanced autophagy in adipocytes from obese patients with type 2 diabetes
    Show others...
    2010 (English)In: Molecular medicine (Cambridge, Mass. Print), ISSN 1076-1551, E-ISSN 1528-3658, Vol. 16, no 07-Aug, p. 235-246Article in journal (Refereed) Published
    Abstract [en]

    The protein kinase mammalian target of rapamycin (mTOR) mediates insulin control ofprotein synthesis, autophagy, mitochondrial function, and, through feedback signaling tophosphorylation of IRS1 at serine residues, mTOR directly controls insulin signaling. Weshow that in adipocytes from patients with type 2 diabetes (T2D) insulin activation of mTORis attenuated and that the resultant phenotype is compatible with, and can be mimicked by,loss of mTOR activation. In T2D adipocytes mitochondrial function is impaired andautophagy strongly upregulated, with concomitant increased autophagic destruction ofmitochondria and lipofuscin particles, and a dependence on autophagy for ATP production.Conversely, mitochondrial dysfunction attenuates insulin activation of mTOR, enhancesautophagy and attenuates feedback to IRS1. Our findings put mTOR in the driver´s seat of aninsulin resistance that in adipocytes can be fuelled by mitochondrial dysfunction,inflammation, ER-stress, or hypoxia.

    Place, publisher, year, edition, pages
    Feinstein Institute for Medical Research, 2010
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-20655 (URN)10.2119/molmed.2010.00023 (DOI)000280048100001 ()20386866 (PubMedID)
    Available from: 2009-09-16 Created: 2009-09-16 Last updated: 2019-06-28Bibliographically approved
  • 101415.
    Öst, Anita
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Danielsson, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lidén, Martin
    Ludwig Institute for Cancer Research, Stockholm, Sweden.
    Eriksson, Ulf
    Ludwig Institute for Cancer Research, Stockholm, Sweden.
    Nyström, Fredrik H
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Endocrinology and Gastroenterology.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Retinol-binding protein-4 attenuates insulin-induced phosphorylation of IRS1 and ERK1/2 in primary human adipocytes2007In: The FASEB journal : official publication of the Federation of American Societies for Experimental Biology, ISSN 1530-6860, Vol. 21, no 13, p. 3696-3704Article in journal (Refereed)
    Abstract [en]

    Reduced sensitivity to insulin in adipose, muscle, and liver tissues is a hallmark of type 2 diabetes. Animal models and patients with type 2 diabetes exhibit elevated levels of circulating retinol-binding protein (RBP4), and RBP4 can induce insulin resistance in mice. However, little is known about how RBP4 affects insulin signaling. We examined the mechanisms of action of RBP4 in primary human adipocytes. RBP4-treated adipocytes exhibited the same molecular defects in insulin signaling, via IRS1 to MAP kinase, as in adipocytes from patients with type 2 diabetes. Without affecting autophosphorylation of the insulin receptor, RBP4 blocked the insulin-stimulated phosphorylation of IRS1 at serine (307) [corresponding to serine (302) in the murine sequence] and concomitantly increased the EC50 (from 0.5 to 2 nM) for insulin stimulation of IRS1 phosphorylation at tyrosine. The phosphorylation of IRS1 at serine (312) [corresponding to serine (307) in the murine sequence] was not affected in cells from diabetic patients and was also not affected by RBP4. The EC50 for insulin stimulation of downstream phosphorylation of MAP kinase ERK1/2 was increased (from 0.2 to 0.8 nM) by RBP4. We show that ERK1/2 phosphorylation is similarly impaired in adipocytes from patients with type 2 diabetes. However, the sensitivity to insulin for downstream signaling to control of protein kinase B and glucose uptake was not affected by RBP4. When insulin-resistant adipocytes from patients with type 2 diabetes were incubated with antibodies against RBP4, insulin-induced phosphorylation of IRS1 at serine (307) was normalized and the EC50 for insulin stimulation of ERK1/2 phosphorylation was reduced. Endogenous levels of RBP4 were markedly reduced in adipocytes from obese or type 2 diabetic subjects, whereas expression levels of RBP4 mRNA were unaffected. These findings indicate that RBP4 may be released from diabetic adipocytes and act locally to inhibit phosphorylation of IRS1 at serine (307), a phosphorylation site that may integrate nutrient sensing with insulin signaling.

  • 101416.
    Öst, Anita
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences. Max Planck Institute Immunobiol and Epigenet, Germany.
    Lempradl, Adelheid
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Casas, Eduard
    Institute Medical Predict and Personalitzada Canc, Spain; ICO Hospital GermansTrias and Pujol, Spain.
    Weigert, Melanie
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Tiko, Theodor
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Deniz, Merdin
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Pantano, Lorena
    Institute Medical Predict and Personalitzada Canc, Spain.
    Boenisch, Ulrike
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Itskov, Pavel M.
    Champalimaud Centre Unknown, Portugal.
    Stoeckius, Marlon
    Max Delbruck Centre Molecular Med, Germany.
    Ruf, Marius
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Rajewsky, Nikolaus
    Max Delbruck Centre Molecular Med, Germany.
    Reuter, Gunter
    University of Halle Wittenberg, Germany.
    Iovino, Nicola
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Ribeiro, Carlos
    Champalimaud Centre Unknown, Portugal.
    Alenius, Mattias
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Heyne, Steffen
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Vavouri, Tanya
    Institute Medical Predict and Personalitzada Canc, Spain; ICO Hospital GermansTrias and Pujol, Spain.
    Pospisilik, J. Andrew
    Max Planck Institute Immunobiol and Epigenet, Germany.
    Paternal Diet Defines Offspring Chromatin State and Intergenerational Obesity2014In: Cell, ISSN 0092-8674, E-ISSN 1097-4172, Vol. 159, no 6, p. 1352-1364Article in journal (Refereed)
    Abstract [en]

    The global rise in obesity has revitalized a search for genetic and epigenetic factors underlying the disease. We present a Drosophila model of paternal-diet-induced intergenerational metabolic reprogramming (IGMR) and identify genes required for its encoding in offspring. Intriguingly, we find that as little as 2 days of dietary intervention in fathers elicits obesity in offspring. Paternal sugar acts as a physiological suppressor of variegation, desilencing chromatin-state-defined domains in both mature sperm and in offspring embryos. We identify requirements for H3K9/K27me3-dependent reprogramming of metabolic genes in two distinct germline and zygotic windows. Critically, we find evidence that a similar system may regulate obesity susceptibility and phenotype variation in mice and humans. The findings provide insight into the mechanisms underlying intergenerational metabolic reprogramming and carry profound implications for our understanding of phenotypic variation and evolution.

  • 101417.
    Öst, Anita
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Pospisilik, John Andrew
    Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
    Epigenetic modulation of metabolic decisions.2015In: Current Opinion in Cell Biology, ISSN 0955-0674, E-ISSN 1879-0410, Vol. 33, p. 88-94Article, review/survey (Refereed)
    Abstract [en]

    In the recent years there has been a tremendous increase in our understanding of chromatin, transcription and the importance of metabolites in their regulation. This review highlights what is currently sparse information that suggest existence of a refined system integrating metabolic and chromatin control. We indicate possible regulatory modes, such as feed forward amplification, that may help effect and stabilize long-lasting phenotypic decisions within and even across generations using adipogenesis as the primary context.

  • 101418.
    Öst, Anita
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Svensson, Kristoffer
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Ruishalme, Iida
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Brännmark, Cecilia
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Franck, Niclas
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Krook, Hans
    Linköping University, Department of Clinical and Experimental Medicine, Surgery . Linköping University, Faculty of Health Sciences.
    Sandström, Per
    Linköping University, Department of Clinical and Experimental Medicine, Surgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Kjølhede, Preben
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics UHL.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Attenuated mTOR signaling and enhanced autophagy in adipocytes from obese patients with type 2 diabetes2010In: Molecular medicine (Cambridge, Mass. Print), ISSN 1076-1551, E-ISSN 1528-3658, Vol. 16, no 07-Aug, p. 235-246Article in journal (Refereed)
    Abstract [en]

    The protein kinase mammalian target of rapamycin (mTOR) mediates insulin control ofprotein synthesis, autophagy, mitochondrial function, and, through feedback signaling tophosphorylation of IRS1 at serine residues, mTOR directly controls insulin signaling. Weshow that in adipocytes from patients with type 2 diabetes (T2D) insulin activation of mTORis attenuated and that the resultant phenotype is compatible with, and can be mimicked by,loss of mTOR activation. In T2D adipocytes mitochondrial function is impaired andautophagy strongly upregulated, with concomitant increased autophagic destruction ofmitochondria and lipofuscin particles, and a dependence on autophagy for ATP production.Conversely, mitochondrial dysfunction attenuates insulin activation of mTOR, enhancesautophagy and attenuates feedback to IRS1. Our findings put mTOR in the driver´s seat of aninsulin resistance that in adipocytes can be fuelled by mitochondrial dysfunction,inflammation, ER-stress, or hypoxia.

  • 101419.
    Öst, Anita
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Örtegren, Unn
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Gustavsson, Johanna
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Nyström, Fredrik H
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Triacylglycerol is synthesized in a specific subclass of caveolae in primary adipocytes2005In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 280, no 1, p. 5-8Article in journal (Refereed)
    Abstract [en]

    A principal metabolic function of adipocytes is to synthesize triacylglycerol (TG) from exogenous fatty acids. The level of fatty acids has to be tightly controlled in the adipocyte, as they can act as detergents that rapidly dissolve the plasma membrane, causing cell lysis if allowed to accumulate. Fatty acids therefore have to be efficiently converted to TG and stored in the central lipid droplet. We report that in intact primary adipocytes exogenous oleic acid was taken up and directly converted to TG in the plasma membrane, in a novel subclass of caveolae that specifically contains the protein perilipin. Isolated caveolae catalyzed de novo TG synthesis from oleic acid and glycerol 3-phosphate. Electron microscopy revealed the presence of caveolin and perilipin in caveolae and in lipid-laden bulbs in the plasma membrane, and fluorescence microscopy demonstrated colocalization of fatty acids/TG with caveolin and perilipin at the plasma membrane. A second caveolae fraction was isolated, which lacked perilipin and the triacylglycerol synthesizing enzymes. Both caveolae fractions contained caveolin-1 and the insulin receptor. The findings demonstrate that specific subclasses of caveolae carry out specific functions in cell metabolism. In particular, triacylglycerol is synthesized at the site of fatty acid entry in one of these caveolae classes.

  • 101420.
    Öst, Gustav
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Search path generation with UAV applications using approximate convex decomposition2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This work focuses on the problem that pertains to area searching with UAVs. Specifically developing algorithms that generate flight paths that are short with- out sacrificing flyability. For instance, very sharp turns will compromise flyability since fixed wing aircraft cannot make very sharp turns. This thesis provides an analysis of different types of search methods, area decompositions, and combi- nations thereof. The search methods used are side to side searching and spiral searching. In side to side searching the aircraft goes back and forth only making 90-degree turns. Spiral search searches the shape in a spiral pattern starting on the outer perimeter working its way in. The idea being that it should generate flight paths that are easy to fly since all turns should be with a large turn radii. Area decomposition is done to divide complex shapes into smaller more manage- able shapes. The report concludes that with the implemented methods the side to side scanning method without area decomposition yields good and above all very reliable results. The reliability stems from the fact that all turns are 90 degrees and that algorithm never get stuck or makes bad mistakes. Only having 90 degree turns results in only four different types of turns. This allows the airplanes behav- ior along the route to be predictable after flying the first four turns. Although this assumes that the strength of the wind is a greater influence than the turbulences effect on the aircraft’s flight characteristics. This is a very valuable feature for an operator in charge of a flight. The other tested methods and area decompositions often yield a shorter flight path, however, despite extensive adjustments to the algorithms they never came to handle all cases in a satisfactory manner. These methods may also generate any kind of turn at any time, including turns of nearly 180 degrees. These turns can lead to an airplane missing the intended flight path and thus missing to scan the intended area properly. Area decomposition proves to be really effective only when the area has many protrusions that stick out in different directions, think of a starfish shape. In these cases the side to side algo- rithm generate a path that has long legs over parts that are not in the search area. When the area is decomposed the algorithm starts with, for example, one arm of the starfish at a time and then search the rest of the arms and body in turn. 

  • 101421.
    Östberg, AL
    et al.
    Public Dental Services and Skaraborg Institute, Skövde.
    Halling, Arne
    Östergötlands Läns Landsting, Public Dental Service.
    Lindblad, U
    Public Dental Services and Skaraborg Institute, Skövde.
    A gender perspective of self-perceived oral health in adolescents: associations with attitudes and behaviours2001In: Community Dental Health, ISSN 0265-539X, Vol. 18, no 2, p. 110-116Article in journal (Refereed)
    Abstract [en]

    Objective To investigate the associations between dental attitudes and behaviours, and self-perceived oral health from a gender perspective in an adolescent population. Design A census survey. Self-reported questionnaires were answered anonymously in a standardised manner in classrooms. Attitudes studied included the importance of sound teeth and feelings towards visits to the dentist. Behaviours were represented by floss usage and sweets consumption. Setting All senior and upper secondary level schools in Skaraborg County, Sweden. Subjects 17,280 students, aged 13-18 years, Outcome measures Self-perceived oral health. represented by a single-item rating: satisfaction with the appearance of the teeth: self-assessed gum bleeding and a perceived oral health (POH) index. Results Recognising sound teeth as important was a predominating attitude among the respondents (boys 94%, girls 97%) and was significantly associated with a good perceived oral health overall. Individuals who experienced visits to dentist as unpleasant (boys 36%, girls 43%) were less likely to perceive good oral health as single-item rated (OR for boys 0.55[0.49, 0.63], girls 0.40[0.34, 0.47]). Regular use of floss had a small protective effect on bleeding gums. Daily sweets consumption showed a significant and inverse association with self-perceived oral health as single-item rated (OR for boys 0.53[0.44, 0.66], girls 0.49[0.40, 0.60]). Girls, more often than boys, perceived their oral health to be good, except in the perception of the appearance of their teeth. Conclusions It is concluded that the strong associations between attitudes and self-perceived oral health should be recognised in strategies for oral health promotion and that gender differences must be considered.

  • 101422.
    Östberg, Gustav
    Linköping University, Department of Electrical Engineering.
    A Comparative Study of Efficient Power Amplifiers in CMOS2008Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During later years communication schemes for handheld devices have increased in complexity due to the desire to increase the throughput, i.e. the amount of information sent over a medium simultaneously. Increasing throughput can be accomplished, not only by modulating the phase or frequency, but also the amplitude. This leads to tougher requirements on the power amplifier. The conventional power amplifiers, which have the ability to follow the envelope of the carrier, are inefficient. This thesis aims to compare two old but revived architectures which exploit high-efficiency amplifiers and still have a linear relationship between the input and output. The architectures; the Polar Linearization Technique and Outphasing share the same foundation. Based on literature, the polar technique have been more successful of employing examples fufilling communication standards. The polar technique is also more versatile regarding power combiners, distortion correction and alternative implementations. The simulations performed in this thesis results show that the polar amplifier is less sensitive to process variations and has higher maximum efficiency. On the other hand, the outphasing topology have the highest linearity figures.

  • 101423.
    Östberg, Jenny
    Linköping University, Department of Management and Economics.
    Prisoner of War or Unlawful Combatant: An Evolution of International Humanitarian Law2006Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The construction of International Humanitarian Law and the norms regarding protection of prisoners of war have evolved as a reaction to the horrors of war. After September 11 and the following war on terrorism the notion of POWs has been widely debated. The USA holds prisoners at the navy base at Guantánamo Bay, Cuba without granting them status as POWs; this thesis is placing the treatment of these detainees within a historical context. The norm concerning rights of POWs is today both internationalized and institutionalized, but that has not always been the case. This thesis illuminates how the norms have evolved during World War I, World War II and Vietnam War; finally the war against terrorism and the treatment of the prisoners at Guantánamo Bay is analyzed. The intention of the thesis is to use a historical overview of the evolution of IHL, and the rights of POWs in particular, to formulate a wider assumption about the implication of IHL in the war against terrorism and the future.

    The thesis adopts a theory which combines constructivism and John Rawls´ theory of justice and uses constructivist ideas about the nature of the international system applied to Rawls´ notion of justice. The constructivist theory and ontology are the basis of the theoretical framework of this thesis and Rawls´ definition of justice as the base of social institutions are viewed from a constructivist perspective. IHL and the norms regarding protection of POWs are thus considered as social facts, constructed and upheld through social interaction between states.

  • 101424.
    Östberg, Linnea
    et al.
    Linköping University, Department of Management and Engineering, Commercial and Business Law. Linköping University, Faculty of Arts and Sciences.
    Uvgård, Louise
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Management and Engineering, Commercial and Business Law.
    Kollektiv dominans: Flera företag enligt artikel 102 FEUF och gränsdragningen gentemot artikel 101 FEUF2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna uppsats är att utreda hur artikel 101 och 102 FEUF förhåller sig till varandra i den beskrivna situationen och därigenom möjliggöra förståelse för hur reglerna skall tolkas. Uppsatsen är främstämnad att riktas till verksamma bolagsjuristermen även till juriststudenter.

  • 101425.
    Östberg, Sofie
    Linköping University, Department of Educational Science (IUV).
    Emma har ingen pappa!: Nio lärares berättelser om hanteringen av barn i sorg.2004Independent thesis Basic level (professional degree)Student thesis
    Abstract [sv]

    Syftet med detta examensarbete är att analysera lärares berättelser om deras hantering av barn som har varit i sorg på grund av en dödshändelse. Jag har genomfört intervjuer med nio lärare som har varit med om att ett barn i klassen eller ett barns anhörig har dött. Fyra centrala teman framträder hos dessa lärares berättelser samt vissa variationer hos dessa. De teman som kan urskiljas i lärarnas berättelser är en stark tilltro till samtal och till kunskap, vikten av att synliggöra sorgen samt vissa värden som ses som viktiga för lärarna i sorgehanteringen. Dessa värden är ärlighet, hänsynstagande,tid, lyssnande samt trygghet.

  • 101426.
    Östblom, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Ekeroth, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Structure and desorption energetics of ultrathin D2O ice overlay ers on serine- And serinephosphate-terminated self-assembled monolayers2006In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1695-1700Article in journal (Refereed)
    Abstract [en]

    This paper reports on the structure and desorption dynamics of thin D 2O ice overlayers (0.2-10 monolayers) deposited on serine- and serinephosphate- (with H+, Na+, Ca2+ counterions) terminated self-assembled monolayers (SAMs). The D2O ice overlayers are deposited on the SAMs at ~85 K in ultrahigh vacuum and characterized with infrared reflection absorption spectroscopy (IRAS). Reflection absorption (RA) spectra obtained at sub-monolayer D2O coverage reveal that surface modes, e.g. free dangling OD stretch, dominate on the serine SAM surface, whereas vibrational modes characteristic for bulk ice are more prominent on the serinephosphate SAMs. Temperature programmed desorption mass spectrometry (TPD-MS) and TPD-IRAS are subsequently used to investigate the energetics and the structural transitions occurring in the ice overlayer during temperature ramping. D2O ice (~2.5 monolayers) on the serine SAMs undergoes a gradual change from an amorphous- to a crystalline-like phase upon increasing the substrate temperature. This transition is not as pronounced on the serine phosphate SAM most likely because of reduced mobility due to strong pinning to the surface. We show also that the energy of desorption for a sub-monolayer of D2O ice on serinephosphate SAM surfaces with a Na+ and Ca2+ counterions is equally high or even exceeds previously reported values for analogous high-energy SAMs. © 2006 American Chemical Society.

  • 101427.
    Östblom, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Demers, L.M.
    Department of Chemistry, Center for Nanofabrication and Molecular Self-Assembly, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208.
    Mirkin, C.A.
    Department of Chemistry, Center for Nanofabrication and Molecular Self-Assembly, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208.
    On the structure and desorption dynamics of DNA bases adsorbed on gold: A temperature-programmed study2005In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 31, p. 15150-15160Article in journal (Refereed)
    Abstract [en]

    The structure and desorption dynamics of mono- and multilayer samples of adenine, cytosine, guanine, and thymine on polycrystalline gold thin films are studied using temperature-programmed desorption-infrared reflection absorption spectroscopy (TPD-IRAS) and temperature-programmed desorption-mass spectroscopy (TPD-MS). It is shown that the pyrimidines, adenine and guanine, adsorb to gold in a complex manner and that both adhesive (adenine) and cohesive (guanine) interactions contribute the apparent binding energies to the substrate surface. Adenine displays at least two adsorption sites, including a high-energy site (210°C, ~136 kj/mol), wherein the molecule coordinates to the gold substrate via the NH2 group in an sp3-like, strongly perturbed, nonplanar configuration. The purines, cytosine and thymine, display a less complicated adsorption/desorption behavior. The desorption energy for cytosine (160°C, ~122 kJ/mol) is similar to those obtained for adenine and guanine, but desorption occurs from a single site of dispersed, nonaggregated cytosine. Thymine desorbs also from a single site but at a significantly lower energy (100°C, ~104 kJ/mol). Infrared data reveal that the monolayer architectures discussed herein are structurally very different from those observed for the bases in the bulk crystalline state. It is also evident that both pyrimidines and purines adsorb on gold with the plane of the molecule in a nonparallel orientation with respect to the substrate surface. The results of this work are discussed in the context of improving the understanding of the design of capturing oligonucleotides or DNA strands for bioanalytical applications, in particular, for gold nanoparticle-based assays. © 2005 American Chemical Society.

  • 101428.
    Östblom, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Valiokas, Ramunas
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Svensson, Stefan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Garrett, M.
    Department of Chemistry and Materials Science, Pennsylvania State University, University Park, PA 16802.
    Allara, D.L.
    Department of Chemistry and Materials Science, Pennsylvania State University, University Park, PA 16802.
    Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments2006In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1830-1836Article in journal (Refereed)
    Abstract [en]

    The nucleation and phase behavior of ultrathin D2O-ice overlayers have been studied on oligo(ethylene glycol) (OEG)-terminated and hydroxyl self-assembled monolayers (SAMs) at low temperatures in ultrahigh vacuum. Infrared reflection-absorption spectroscopy (IRAS) is used to characterize the ice overlayers, the SAMs, and the interactions occurring between the ice and the SAM surfaces. Spectral simulations, based on optical models in conjunction with Maxwell Garnett effective medium theory, point out the importance of including voids in the modeling of the ice structures, with void fractions reaching 60% in some overlayers. The kinetics of the phase transition from amorphous-like to crystalline-like ice upon isothermal annealing at 140 K is found to depend on the conformational state of the supporting OEG SAM surface. The rate is fast on the helical OEG SAMs and slow on the corresponding all-trans SAMs. This difference in kinetics is most likely due to a pronounced D2O interpenetration and binding to the all-trans segments of the ethylene glycol portion of the SAM. No such penetration and binding was observed on the helical OEG SAM. © 2006 American Chemical Society.

  • 101429.
    Östensson, Frida
    Linköping University, Department of Physics, Chemistry and Biology, Biology.
    Grain protein content and its assocoation with the NAC-protein genes HvNAM1 and HvNAM2 in Nordic barley2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Hunger is a problem faced by many people all over the world, and as the population grows, so does the need for food such as cereals. Because of this, the need for food with higher protein and nutrient content will be increasingly important. NAM-B1, a NAC-protein gene in wheat, has been shown to control the grain protein content and nutrient values, as well as senescence. In barley, two orthologous genes have been found, HvNAM1 and HvNAM2. This study focuses on Nordic barley accessions and how haplotypes of HvNAM1 and HvNAM2 correlate to the grain protein content (GPC) and nutrient content. No correlations between the different haplotypes of the HvNAM genes and the nutrient content and GPC were found. No differences in nutrient content and GPC were found in Nordic accessions originating from Sweden, Norway, Finland, or Denmark, nor were differences found for improvements status groups or for six-row barley and two-row barley. The Nordic accessions were shown to generally have high GPC when compared to control groups Karl and Lewis. However, even if the results of this study indicate that the HvNAM genes do not have major effects on the nutrient contents or GPC, Nordic barley might still be good material for plant improvement. Other factors such as other genes, environmental effects, and gene expression should therefore be investigated.

  • 101430.
    Öster, Michael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics.
    Nonlinear Localisation in classical lattices2006In: Science and Supercomputing in Europe / [ed] Michael Öster, Bologna: Centro di Calcolo Interuniversitario dell´Italia NordOrientale , 2006, p. 754-757Chapter in book (Other academic)
    Abstract [en]

  • 101431.
    Öster, Michael
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Nonlinear localization in discrete and continuum systems: applications for optical waveguide arrays2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    An introcludion to the formation of coherent structures in spatially discrete and continuous systems is given. Of special interest is the phenomenon of nonlinear localization, where the self-focusing of an excitation is balanced by a dispersive process. This leads to the existence of localized waves (solitons) in continuous systems, and under very general conditions to intrinsic localized modes (discrete breathers) in systems of coupled anharmonic oscillators. Focus is set on nonlinear Schrödinger equations. A discrete equation, describing the propagation of the electric field in an array of coupled optical waveguides embedded in a material with a nonlinear index of refraction of the Kerr-type, is derived. The equation also describes the evolution of weakly coupled Bose-Einstein condensates in a periodic potential. The model contains nonlinear coupling terms and an effort is made to understand the novel features introduced by these terms as well as the nonlinear dispersion arising from taking the continuum limit of the discrete equation.

    Important contributions in the papers are the discovery of inversion of stability between stationary excitations localized, respectively, on and in between sites in the lattice model for waveguide arrays, leading to an enhanced mobility of highly localized modes. As these can be controlled by simple perturbations. they may have an important applicat ion for optical multiport switching. The nonlinear coupling terms also lead to existence of discrete breathers with compact support and to a new type of stationary, complex, phase-twisted modes not previously reported. Of interest is also the possibility of controlling the magnitude and direction of the norm (Poynting power) current flowing across the waveguide array by simple non-symmetry-breaking perturbations. For the continuum equation, the nonlinear dispersion leads to the formation of exotic solitons, i.e., localized waves with discontinuous derivatives. The emergence of short-wavelength instabilities due to the simultaneous presence of nonlocal and nonlinea.r dispersion is also explained.

    List of papers
    1. Enhanced mobility of strongly localized modes in waveguide arrays by inversion of stability
    Open this publication in new window or tab >>Enhanced mobility of strongly localized modes in waveguide arrays by inversion of stability
    2003 (English)In: Physical Review E, ISSN 1063-651X, Vol. 67, no 5, p. 056606-1--056606-8Article in journal (Refereed) Published
    Abstract [en]

    A model equation governing the amplitude of the electric field in an array of coupled optical waveguides embedded in a material with Kerr nonlinearities is derived and explored. The equation is an extended discrete nonlinear Schrödinger equation with intersite nonlinearities. Attention is turned towards localized solutions and investigations are made from the viewpoint of the theory of discrete breathers (DBs). Stability analysis reveals an inversion of stability between stationary one-site and symmetric or antisymmetric two-site solutions connected to bifurcations with a pair of asymmetric intermediate DBs. The stability inversion leads to the existence of high-intensity narrow mobile solutions, which can propagate essentially radiationless. The direction and transverse velocity of the mobile solutions can be controlled by appropriate perturbations. Such solutions may have an important application for multiport switching, allowing unambiguous selection of output channel. The derived equation also supports compact DBs, which in some sense yield the best possible solutions for switching purposes.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14237 (URN)10.1103/PhysRevE.67.056606 (DOI)
    Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2014-01-13
    2. Nonlocal and nonlinear dispersion in a nonlinear Schrödinger-type equation: exotic solitons and short-wavelength instabilities
    Open this publication in new window or tab >>Nonlocal and nonlinear dispersion in a nonlinear Schrödinger-type equation: exotic solitons and short-wavelength instabilities
    2004 (English)In: Physica D: Nonlinear Phenomena, ISSN 0167-2789, Vol. 198, no 1-2, p. 29-50Article in journal (Refereed) Published
    Abstract [en]

    We study the continuum limit of a nonlinear Schrödinger lattice model with both on-site and inter-site nonlinearities, describing weakly coupled optical waveguides or Bose–Einstein condensates. The resulting continuum nonlinear Schrödinger-type equation includes both nonlocal and nonlinear dispersion. Looking for stationary solutions, the equation is reduced to an ordinary differential equation with a rescaled spectral parameter and a single parameter interpolating between the nonlocality and the nonlinear dispersion. It is seen that these two effects give a similar behaviour for the solutions. We find smooth solitons and, beyond a critical value of the spectral parameter, also nonanalytic solitons in the form of peakons and capons. The existence of the exotic solitons is connected to the special properties of the phase space of the equation. Stability is investigated numerically by calculating eigenvalues and eigenfunctions of the linearized problem, and we particularly find that with both nonlocal and nonlinear dispersion simultaneously present, all solutions are unstable with respect to a break-up into short-wavelength oscillations.

    Keywords
    Nonlinear Schrödinger, Nonlinear dispersion, Nonlocal dispersion, Exotic solitons, Modulational instability
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14238 (URN)10.1016/j.physd.2004.08.007 (DOI)
    Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2014-01-13
    3. Phase twisted modes and current reversals in a lattice model of waveguide arrays with nonlinear coupling
    Open this publication in new window or tab >>Phase twisted modes and current reversals in a lattice model of waveguide arrays with nonlinear coupling
    2005 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 71, no 2, p. 025601-1--025601-4Article in journal (Refereed) Published
    Abstract [en]

    We consider a lattice model for waveguide arrays embedded in nonlinear Kerr media. Inclusion of nonlinear coupling results in many phenomena involving complex, phase-twisted, stationary modes. The norm (Poynting power) current of stable plane-wave solutions can be controlled in magnitude and direction, and may be reversed without symmetry-breaking perturbations. Also stable localized phase-twisted modes with zero current exist, which for particular parameter values may be compact and expressed analytically. The model also describes coupled Bose-Einstein condensates.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14239 (URN)10.1103/PhysRevE.71.025601 (DOI)
    Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2017-12-13
  • 101432.
    Öster, Michael
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Stability and Mobility of Localized and Extended Excitations in Nonlinear Schrödinger Models2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is mainly concerned with the properties of some discrete nonlinear Schrödinger equations. These naturally arise in many different physical contexts as the limiting form of general dynamical lattice equations that incorporate nonlinearity and coupling. Interest is focused on theoretical models of coupled optical waveguides constructed from materials with a nonlinear index of refraction. In arrays of waveguides the overlap of the evanescent electric field of the modes in neighbouring waveguides provides a coupling and the nonlinearity of the material provides a mechanism to halt the discrete diffraction that otherwise would spread localized energy across the array. In particular, waveguide structures where also a nonlinear coupling is taken into account are studied. It is noted that the equation for the evolution of the complex amplitudes of the electric field along an array of waveguides also can be used to describe the dynamics of Bose-Einstein condensates trapped in a periodic optical potential. Possible excitations in arrays in both one and two dimensions are considered, with emphasis on the effects of the nonlinear coupling.

    Localized excitations are considered from the viewpoint of the theory of discrete breathers, or intrinsic localized modes, i.e., solutions of the dynamical equations that are periodic in time and have a spatial localization. The general theory of such solutions, that appear under very general circumstances in nonlinear lattice equations, is reviewed. In an array of waveguides this means that light can propagate along the array confined essentially to one or a few waveguides. In general a distinction is made between excitations that are centred on a waveguide, or site in the lattice, and excitations that are centred inbetween waveguides. Usually only the former give stable propagation. When the localized beam can be displaced to neighbouring waveguides the array can operate as an optical switch. With the inclusion of nonlinear coupling between the sites, as in the model derived in this thesis, the stability of the site-centred and bond-centred solutions can be exchanged. It is shown how this leads to the existence of highly localized mobile solutions that can propagate transversely in the one-dimensional array of waveguides. The inversion of stability of stationary solutions occurs also in the two-dimensional array, but in this setting it fails to give good mobility of localized excitations. The reason for this is also explained.

    In a two-dimensional lattice a discrete breather can have the form of a vortex. This means that the phase of the complex amplitude will vary on a contour around the excitation, such that the phase is increased by 2πS, where S is the topological charge, on the completion of one turn. Some ring-like vortex excitations are considered and in particular a stable vortex with S=2 is found. It is also noted that the effect of charge flipping, i.e., when the topological charge periodically changes between -S and S, is connected to the existence of quasiperiodic solutions.

    The nonlinear coupling of the waveguide model will also give rise to some more exotic and novel properties of localized solutions, e.g., discrete breathers with a nontrivial phase. When the linear coupling and the nonlinear coupling have opposite signs, there can be a decoupling in the lattice that allows for compact solutions. These localized excitations will have no decaying tail. Of interest is also the flexibility in controlling the transport of power across the array when it is excited with a nonlinear plane wave. It is shown how a change of the amplitude of a plane wave can affect the magnitude and direction of power flow in the array.

    Also the continuum limit of the one-dimensional discrete waveguide model is considered with an equation incorporating both nonlocal and nonlinear dispersion. In general continuum equations the balance between nonlinearity and dispersion can lead to the formation of localized travelling waves, or solitons. With nonlinear dispersion it is seen that these solitons can be nonanalytic and have discontinuous spatial derivatives. The emergence of short-wavelength instabilities due to the simultaneous presence of nonlocal and nonlinear dispersion is also explained.

    List of papers
    1. Enhanced mobility of strongly localized modes in waveguide arrays by inversion of stability
    Open this publication in new window or tab >>Enhanced mobility of strongly localized modes in waveguide arrays by inversion of stability
    2003 (English)In: Physical Review E, ISSN 1063-651X, Vol. 67, no 5, p. 056606-1--056606-8Article in journal (Refereed) Published
    Abstract [en]

    A model equation governing the amplitude of the electric field in an array of coupled optical waveguides embedded in a material with Kerr nonlinearities is derived and explored. The equation is an extended discrete nonlinear Schrödinger equation with intersite nonlinearities. Attention is turned towards localized solutions and investigations are made from the viewpoint of the theory of discrete breathers (DBs). Stability analysis reveals an inversion of stability between stationary one-site and symmetric or antisymmetric two-site solutions connected to bifurcations with a pair of asymmetric intermediate DBs. The stability inversion leads to the existence of high-intensity narrow mobile solutions, which can propagate essentially radiationless. The direction and transverse velocity of the mobile solutions can be controlled by appropriate perturbations. Such solutions may have an important application for multiport switching, allowing unambiguous selection of output channel. The derived equation also supports compact DBs, which in some sense yield the best possible solutions for switching purposes.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14237 (URN)10.1103/PhysRevE.67.056606 (DOI)
    Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2014-01-13
    2. Nonlocal and nonlinear dispersion in a nonlinear Schrödinger-type equation: exotic solitons and short-wavelength instabilities
    Open this publication in new window or tab >>Nonlocal and nonlinear dispersion in a nonlinear Schrödinger-type equation: exotic solitons and short-wavelength instabilities
    2004 (English)In: Physica D: Nonlinear Phenomena, ISSN 0167-2789, Vol. 198, no 1-2, p. 29-50Article in journal (Refereed) Published
    Abstract [en]

    We study the continuum limit of a nonlinear Schrödinger lattice model with both on-site and inter-site nonlinearities, describing weakly coupled optical waveguides or Bose–Einstein condensates. The resulting continuum nonlinear Schrödinger-type equation includes both nonlocal and nonlinear dispersion. Looking for stationary solutions, the equation is reduced to an ordinary differential equation with a rescaled spectral parameter and a single parameter interpolating between the nonlocality and the nonlinear dispersion. It is seen that these two effects give a similar behaviour for the solutions. We find smooth solitons and, beyond a critical value of the spectral parameter, also nonanalytic solitons in the form of peakons and capons. The existence of the exotic solitons is connected to the special properties of the phase space of the equation. Stability is investigated numerically by calculating eigenvalues and eigenfunctions of the linearized problem, and we particularly find that with both nonlocal and nonlinear dispersion simultaneously present, all solutions are unstable with respect to a break-up into short-wavelength oscillations.

    Keywords
    Nonlinear Schrödinger, Nonlinear dispersion, Nonlocal dispersion, Exotic solitons, Modulational instability
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14238 (URN)10.1016/j.physd.2004.08.007 (DOI)
    Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2014-01-13
    3. Phase twisted modes and current reversals in a lattice model of waveguide arrays with nonlinear coupling
    Open this publication in new window or tab >>Phase twisted modes and current reversals in a lattice model of waveguide arrays with nonlinear coupling
    2005 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 71, no 2, p. 025601-1--025601-4Article in journal (Refereed) Published
    Abstract [en]

    We consider a lattice model for waveguide arrays embedded in nonlinear Kerr media. Inclusion of nonlinear coupling results in many phenomena involving complex, phase-twisted, stationary modes. The norm (Poynting power) current of stable plane-wave solutions can be controlled in magnitude and direction, and may be reversed without symmetry-breaking perturbations. Also stable localized phase-twisted modes with zero current exist, which for particular parameter values may be compact and expressed analytically. The model also describes coupled Bose-Einstein condensates.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14239 (URN)10.1103/PhysRevE.71.025601 (DOI)
    Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2017-12-13
    4. Stable stationary and quasiperiodic discrete vortex breathers with topological charge S=2
    Open this publication in new window or tab >>Stable stationary and quasiperiodic discrete vortex breathers with topological charge S=2
    2006 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 73, no 6, p. 066608-1--066608-6Article in journal (Refereed) Published
    Abstract [en]

    We demonstrate the stability of a stationary vortex breather with vorticity S=2 in the two-dimensional discrete nonlinear Schrödinger model for a square lattice and also discuss the effects of exciting internal sites in a vortex ring. We also point out the fundamental difficulties of observing these solutions with current experimental techniques. Instead, we argue that relevant initial conditions will lead to the formation of quasiperiodic vortex breathers.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14240 (URN)10.1103/PhysRevE.73.066608 (DOI)
    Available from: 2007-01-26 Created: 2007-01-26 Last updated: 2017-12-13
    5. Stability, mobility and power currents in a two-dimensional model for waveguide arrays with nonlinear coupling
    Open this publication in new window or tab >>Stability, mobility and power currents in a two-dimensional model for waveguide arrays with nonlinear coupling
    2009 (English)In: Physica D: Non-linear phenomena, ISSN 0167-2789, E-ISSN 1872-8022, Vol. 238, no 1, p. 88-99Article in journal (Refereed) Published
    Abstract [en]

    A two-dimensional nonlinear Schrodinger lattice with nonlinear coupling, modelling a square array of weakly coupled linear optical waveguides embedded in a nonlinear Kerr material, is studied. We find that despite a vanishing energy difference (Peierls-Nabarro barrier) of fundamental stationary modes the mobility of localized excitations is very poor. This is attributed to a large separation in parameter space of the bifurcation points of the involved stationary modes. At these points the stability of the fundamental modes is changed and an asymmetric intermediate solution appears that connects the points. The control of the power flow across the array when excited with plane waves is also addressed and shown to exhibit great flexibility that may lead to applications for power-coupling devices. In certain parameter regimes, the direction of a stable propagating plane-wave current is shown to be continuously tunable by amplitude variation (with fixed phase gradient). More exotic effects of the nonlinear coupling terms like compact discrete breathers and vortices, and stationary complex modes with nontrivial phase relations are also briefly discussed. Regimes of dynamical linear stability are found for all these types of solutions.

    Keywords
    Nonlinear coupling, Peierls-Nabarro potential, Mobility, Inversion of stability, Modulational instability, Power currents
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-16345 (URN)10.1016/j.physd.2008.08.006 (DOI)
    Available from: 2009-01-16 Created: 2009-01-16 Last updated: 2017-12-14
  • 101433.
    Öster, Michael
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Gaididei, Yuri B.
    Informatics and Mathematical Modelling and Department of Physics, The Technical University of Denmark, Lyngby, Denmark.
    Johansson, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Christiansen, Peter L.
    Informatics and Mathematical Modelling and Department of Physics, The Technical University of Denmark, Lyngby, Denmark.
    Nonlocal and nonlinear dispersion in a nonlinear Schrödinger-type equation: exotic solitons and short-wavelength instabilities2004In: Physica D: Nonlinear Phenomena, ISSN 0167-2789, Vol. 198, no 1-2, p. 29-50Article in journal (Refereed)
    Abstract [en]

    We study the continuum limit of a nonlinear Schrödinger lattice model with both on-site and inter-site nonlinearities, describing weakly coupled optical waveguides or Bose–Einstein condensates. The resulting continuum nonlinear Schrödinger-type equation includes both nonlocal and nonlinear dispersion. Looking for stationary solutions, the equation is reduced to an ordinary differential equation with a rescaled spectral parameter and a single parameter interpolating between the nonlocality and the nonlinear dispersion. It is seen that these two effects give a similar behaviour for the solutions. We find smooth solitons and, beyond a critical value of the spectral parameter, also nonanalytic solitons in the form of peakons and capons. The existence of the exotic solitons is connected to the special properties of the phase space of the equation. Stability is investigated numerically by calculating eigenvalues and eigenfunctions of the linearized problem, and we particularly find that with both nonlocal and nonlinear dispersion simultaneously present, all solutions are unstable with respect to a break-up into short-wavelength oscillations.

  • 101434.
    Öster, Michael
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Johansson , Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Stability, mobility and power currents in a two-dimensional model for waveguide arrays with nonlinear coupling2009In: Physica D: Non-linear phenomena, ISSN 0167-2789, E-ISSN 1872-8022, Vol. 238, no 1, p. 88-99Article in journal (Refereed)
    Abstract [en]

    A two-dimensional nonlinear Schrodinger lattice with nonlinear coupling, modelling a square array of weakly coupled linear optical waveguides embedded in a nonlinear Kerr material, is studied. We find that despite a vanishing energy difference (Peierls-Nabarro barrier) of fundamental stationary modes the mobility of localized excitations is very poor. This is attributed to a large separation in parameter space of the bifurcation points of the involved stationary modes. At these points the stability of the fundamental modes is changed and an asymmetric intermediate solution appears that connects the points. The control of the power flow across the array when excited with plane waves is also addressed and shown to exhibit great flexibility that may lead to applications for power-coupling devices. In certain parameter regimes, the direction of a stable propagating plane-wave current is shown to be continuously tunable by amplitude variation (with fixed phase gradient). More exotic effects of the nonlinear coupling terms like compact discrete breathers and vortices, and stationary complex modes with nontrivial phase relations are also briefly discussed. Regimes of dynamical linear stability are found for all these types of solutions.

  • 101435.
    Öster, Michael
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Johansson, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Phase twisted modes and current reversals in a lattice model of waveguide arrays with nonlinear coupling2005In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 71, no 2, p. 025601-1--025601-4Article in journal (Refereed)
    Abstract [en]

    We consider a lattice model for waveguide arrays embedded in nonlinear Kerr media. Inclusion of nonlinear coupling results in many phenomena involving complex, phase-twisted, stationary modes. The norm (Poynting power) current of stable plane-wave solutions can be controlled in magnitude and direction, and may be reversed without symmetry-breaking perturbations. Also stable localized phase-twisted modes with zero current exist, which for particular parameter values may be compact and expressed analytically. The model also describes coupled Bose-Einstein condensates.

  • 101436.
    Öster, Michael
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Johansson, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Stability and Mobility of Localised Modes in One- and Two-dimensional DNLS Equations with Non-linear Coupling2006In: SIAM Conference on Nonlinear Waves and Coherent Structures,2006, 2006Conference paper (Other academic)
  • 101437.
    Öster, Michael
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Johansson, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Stable stationary and quasiperiodic discrete vortex breathers with topological charge S=22006In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 73, no 6, p. 066608-1--066608-6Article in journal (Refereed)
    Abstract [en]

    We demonstrate the stability of a stationary vortex breather with vorticity S=2 in the two-dimensional discrete nonlinear Schrödinger model for a square lattice and also discuss the effects of exciting internal sites in a vortex ring. We also point out the fundamental difficulties of observing these solutions with current experimental techniques. Instead, we argue that relevant initial conditions will lead to the formation of quasiperiodic vortex breathers.

  • 101438.
    Öster, Michael
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Johansson, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Eriksson, Anders
    Enhanced mobility of strongly localized modes in waveguide arrays by inversion of stability2003In: Physical Review E, ISSN 1063-651X, Vol. 67, no 5, p. 056606-1--056606-8Article in journal (Refereed)
    Abstract [en]

    A model equation governing the amplitude of the electric field in an array of coupled optical waveguides embedded in a material with Kerr nonlinearities is derived and explored. The equation is an extended discrete nonlinear Schrödinger equation with intersite nonlinearities. Attention is turned towards localized solutions and investigations are made from the viewpoint of the theory of discrete breathers (DBs). Stability analysis reveals an inversion of stability between stationary one-site and symmetric or antisymmetric two-site solutions connected to bifurcations with a pair of asymmetric intermediate DBs. The stability inversion leads to the existence of high-intensity narrow mobile solutions, which can propagate essentially radiationless. The direction and transverse velocity of the mobile solutions can be controlled by appropriate perturbations. Such solutions may have an important application for multiport switching, allowing unambiguous selection of output channel. The derived equation also supports compact DBs, which in some sense yield the best possible solutions for switching purposes.

  • 101439.
    Österberg, Anders
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences.
    Central pain in multiple sclerosis: clinical characteristics, sensory abnormalities and treatment2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the present research programme the occurrence of pain in MS was investigated, with special emphasis on central pain (CP). Questionnaires were sent to all 429 patients with definite MS in the patient register at our neurology department. All admitting to pain were interviewed by telephone and offered an extended interview and examination at the out patient department. 364 patients replied (86%), of whom 58% reported pain during the course of their disease (21% nociceptive, 2% peripheral neuropathic and 1% related to spasticity). 1 DO patients (27,5%) had CP, including 18 patients (4,9%) with trigeminal neuralgia (TN). Non-trigeminal CP was, in 87%, located in the lower extremities and in 31% in the upper. lt was mostly bilateral (76%) and constant, with 88% experiencing daily pain. Only 2% had paroxysmal attacks. Aching, burning and pricking were the commonest qualities. The pain was intense with little to moderate spontaneous variation. In 5,5% of all patients (20% of the patients with CP), pain was a presenting symptom, alone or in combination with other symptoms. Trigeminal neuralgia in our MS patients started later in life and after longer disease duration than did nontrigeminal pain. Both types of CP existed either chronically or as a feature of relapse.

    Somatosensory abnormalities were analysed in detail using traditional neurological tests and quantitative methods for sensory tests (QST) in 62 patients with non-trigeminal CP and in a control group of 16 patients with MS and sensory symptoms, but without pain. 97 per cent of the CP patients had abnormal sensibility to temperature and pain, compared to 81% in the control group (p<0.05), whereas there was a tendency towards the opposite regarding sensibility to touch, which was decreased in 66% vs. 87% (n.s), vibration (81% vs. 55%; n.s) and to joint movement (32% vs. 62%; p<0.04).

    Comparison between painful and non-painful regions showed significantly more abnormal sensibility, in the CP regions, for warmth (p<0.001 ), cold (p<0.05), difference limen (innoxious warmth and cold, p<0.01), cold pain (p<0.01), and heat pain/cold pain combined (p<0.001). There were similar differences between CP regions and regions with sensory symptoms, in the controls, for warmth (p<0.05), cold (p<0.01), difference limen (innoxious warmth and cold, p<0.01) and heat pain/cold pain combined (p<0.001).

    These results indicate that MS patients with CP have lesions affecting the spinothalamo-cortical pathways (temperature and pain), and that the lesions affect the mediallemniscal pathways (touch, position sense and vibration) to a lesser degree. The opposite was found in the control group.

    The results support the general hypothesis that only patients who have lesions affecting the spinothalamo-cortical pathways run the risk of developing CP.

    23 MS patients with non-trigeminal CP participated in a double-blind 3-phase, crossover, placebo-controlled study on the pain-relieving effect of amitriptyline and carbamazepine. Each drug was given in randomised order, for a period of 4 weeks, separated by a one-week washout. The target dose was 75 mg for amitriptyline and 600 mg for carbamazepine (reduced from 800 mg because of side-effects). The effect of treatment was assessed by daily ratings of pain using a 10-step verbal rating scale and at the end of each treatment period by a global rating 5-step verbal scale. Due to the high incidence of side-effects 12 and 7 patients discontinued carbamazepine and amitriptyline, respectively. For carbamazepine, these occurred at unexpectedly small doses; 100-200 mg. Amitriptyline, but not carbamazepine, showed a statistically significant pain reduction compared to placebo (p<0.05). According to the global rating, nine of 14 patients were responders. The effect was already noticed during the second week of treatment and it appeared to be correlated to the plasma concentration. Two of 9 patients treated with carbamazepine reported some pain relief, but the effect did not reach statistical significance compared to placebo, and no correlation was found between effect and plasma concentration.

    14 opioid-free patients with non-trigeminal CP caused by MS were investigated. Placebo (normal saline), morphine and naloxone were given intravenously in a standardised manner. The design was a non-randomised, single blind, placebo-controlled trial. For pain assessment a visual analogue scale (0-100 mm) was used. Four patients were opioid-responders, i.e. experienced minimal or no effect on pain with placebo, >50% pain reduction after morphine, and >25% pain increase when naloxone was given after morphine. However, the response was obtained only after high doses of morphine (mean 41 mg). Thus, in contrast to nociceptive pain, only a minority of the patients with CP due to MS responded to morphine and only at high doses. These results are in accordance with experimental studies indicating that neuropathic pain is poorly responsive, but not totally unresponsive to opioids.

    List of papers
    1. Central pain in multiple sclerosis: prevalence and clinical characteristics
    Open this publication in new window or tab >>Central pain in multiple sclerosis: prevalence and clinical characteristics
    2005 (English)In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 9, no 5, p. 531-542Article in journal (Refereed) Published
    Abstract [en]

    Pain is more common in multiple sclerosis (MS) than has previously been recognised. In the present study we have investigated the occurrence of central pain (CP) in MS and defined its characteristics. Questionnaires were sent to all 429 patients with definite MS in the patient register at our neurology department. All admitting to pain were interviewed and offered an extended interview and examination. Three hundred and sixty four patients responded (86%), of whom 57.5% reported pain during the course of their disease (21% nociceptive, 2% peripheral neuropathic and 1% related to spasticity). One hundred patients (27.5%) had CP, including 18 patients (4.9%) with trigeminal neuralgia.

    The non-trigeminal CP was, in 87%, located in the lower and in 31% in the upper extremities. It was mostly bilateral (76%) and constant, with 88% experiencing daily pain. Only 2% had paroxysmal attacks. Aching, burning, pricking were the commonest qualities. The pain was intense with small to moderate spontaneous variation. In 5.5% of all patients (20% of the patients with CP), pain was a presenting symptom, alone or in combination with other symptoms.

    The most common neurological symptoms/signs besides CP were sensory abnormalities (98%, dominated by abnormal sensibility to painful stimulus and temperature). Trigeminal neuralgia in MS started later in life and after longer disease duration than non-trigeminal pain. Both types of CP existed either chronically or as a feature of relapse. Central pain is thus an important symptom in MS (around 30%) and causes much suffering.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-31877 (URN)10.1016/j.ejpain.2004.11.005 (DOI)17705 (Local ID)17705 (Archive number)17705 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13Bibliographically approved
    2. Central pain in multiple sclerosis: sensory abnormalities
    Open this publication in new window or tab >>Central pain in multiple sclerosis: sensory abnormalities
    2010 (English)In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 14, no 1, p. 104-110Article in journal (Refereed) Published
    Abstract [en]

    Many patients with multiple sclerosis (MS) develop central neuropathic pain (CP). In the present study somatosensory abnormalities have been analysed in detail in 62 patients with MS and CP (42 women, 20 men; mean age 52 years) and in a control group of 10 women and 6 men (mean age 47 years) with MS and sensory symptoms, but without pain.

    Assessment included clinical testing and quantitative methods (QST) for the measurement of perception thresholds for touch, vibration, and temperatures.

    All CP patients except two (97%) had abnormal thresholds for innoxious and/or noxious temperatures, compared to 81% in the control group (p < 0.05). There was a tendency towards the opposite regarding sensibility to touch, which was decreased in 66% vs. 87% (n.s.), vibration (55% vs. 81%; n.s.) and to joint movement (32% vs. 62%; p < 0.04).

    Comparisons between painful and non-painful regions showed both the absolute threshold values and the index values to be significantly more abnormal, in the CP regions, for warmth (p < 0.001), cold (p < 0.05), difference limen (innoxious warmth and cold, p < 0.01), cold pain (p < 0.01) and heat pain/cold pain combined (p < 0.001).

    Also the comparisons between regions with central pain and regions with sensory symptoms in the controls showed significantly more abnormal thresholds in the CP patients for warmth (p < 0.05), cold (p < 0.01), difference limen (innoxious warmth and cold, p < 0.01) and heat pain/cold pain combined (p < 0.001).

    The results support the general hypothesis that only patients who have lesions affecting the spinothalamo-cortical pathways run the risk of developing central pain.

    Keywords
    Multiple sclerosis, Central neuropathic pain, Sensibility, Quantitative sensory test (QST)
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-54155 (URN)10.1016/j.ejpain.2009.03.003 (DOI)000274481800017 ()
    Available from: 2010-02-26 Created: 2010-02-26 Last updated: 2017-12-12Bibliographically approved
    3. Central pain in multiple sclerosis: a double-blind placebo-controlled trial of amitriptyline and carbamazepine
    Open this publication in new window or tab >>Central pain in multiple sclerosis: a double-blind placebo-controlled trial of amitriptyline and carbamazepine
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Approximately 23% of all MS patients suffer from non-trigeminal, nonparoxysmal central pain (CP). This pain is generally considered difficult to treat effectively; tricyclic antidepressants, anti epileptic drugs or analgesics are most commonly used. In this study, the pain relieving effects of amitriptyline and carbamazepine were investigated.

    The design was a randomised double-blind, three-phase, crossover, placebo-controlled trial. Twenty-three patients with definitive MS entered the study (mean age 55 year, range 40-79 years), all had been thoroughly investigated in a project on CP in MS, and no one showed signs of depression. The treatment phases lasted four weeks, and were separated by a one-week washout. The final doses were 75 mg for amitriptyline and 600 mg for carbamazepine (adjusted from 800 mg, because of side-effects). The effect of treatment was assessed by two daily ratings of pain using a 10- step verbal rating scale (VRS), and at the end of each treatment period using a 5-step global rating scale. For the assessment of depression the Comprehensive Psychopathological Rating Scale (CPRS) was used.

    Originally 23 patients were included in the study, but due to side-effects 7 patients discontinued during the amitriptyline phase, and 12 during the carbamazepine phase. With carbamazepine this occurred at low doses (100-200 mg).

    The results show that amitriptyline significantly reduced non-paroxysmal CP in MS, compared to placebo (VRS 4.2 vs. 5.3; p<0.05) and according to the global rating; nine of 14 patients were responders (64%). The effect could already be seen during the second week of treatment. The plasma concentrations of amitriptyline and its active metabolite nortriptyline were higher in the responders (329 nmol/l) that in the non-responders (252 nmol/l, n.s). CPRS scores for depression were normal, and were not altered by the medication.

    Two of nine patients treated with carbamazepine reported some pain relief, but the effect did not reach significance when compared with placebo. No correlation was found between effect and plasma concentration.

    It is concluded that amitriptyline, but not carbamazepine, has a weak effect on non-paroxysmal CP in MS, and that MS patients appear to be particularly sensitive to the side-effects of the two drugs.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-81949 (URN)
    Available from: 2012-09-26 Created: 2012-09-26 Last updated: 2012-09-26Bibliographically approved
    4. Morphine responsiveness in a group of well-defined multiple sclerosis patients: a study with i.v. morphine
    Open this publication in new window or tab >>Morphine responsiveness in a group of well-defined multiple sclerosis patients: a study with i.v. morphine
    Show others...
    2002 (English)In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 6, no 1, p. 69-80Article in journal (Refereed) Published
    Abstract [en]

    Pain in multiple sclerosis (MS) is more common than has previously been believed. About 28% of all MS patients suffer from central pain (CP), a pain that is difficult to treat. In the present study we have investigated the responsiveness of this pain to morphine. Fourteen opioid-free patients (eight woman and six men) with constant, non-fluctuating, long-lasting CP caused by MS were investigated. Placebo (normal saline), morphine and naloxone were given intravenously in a standardized manner. The study design was non-randomized, single blind and placebo controlled. Ten patients experienced less than 50% pain reduction by placebo and less than 50% pain reduction by morphine. Four patients were opioid responders, i.e. had minimal or no effect on pain by placebo, >50% pain reduction after morphine and >25% pain increase after naloxone, given intravenously following morphine. However, this response was obtained after high doses of morphine (43 mg, 47 mg, 50 mg and 25 mg; mean 41 mg). Thus, compared with nociceptive pain, only a minority of the patients with CP due to MS responded to morphine and only at high doses. The present results are in accord with experimental studies indicating that neuropathic pain is poorly responsive but not totally unresponsive to opioids. The results do not support the routine use of strong opioids in MS patients with CP.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26814 (URN)10.1053/eujp.2001.0307 (DOI)11425 (Local ID)11425 (Archive number)11425 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
  • 101440.
    Österberg, Anders
    et al.
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences.
    Boivie, Jörgen
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences.
    Central pain in multiple sclerosis: a double-blind placebo-controlled trial of amitriptyline and carbamazepineManuscript (preprint) (Other academic)
    Abstract [en]

    Approximately 23% of all MS patients suffer from non-trigeminal, nonparoxysmal central pain (CP). This pain is generally considered difficult to treat effectively; tricyclic antidepressants, anti epileptic drugs or analgesics are most commonly used. In this study, the pain relieving effects of amitriptyline and carbamazepine were investigated.

    The design was a randomised double-blind, three-phase, crossover, placebo-controlled trial. Twenty-three patients with definitive MS entered the study (mean age 55 year, range 40-79 years), all had been thoroughly investigated in a project on CP in MS, and no one showed signs of depression. The treatment phases lasted four weeks, and were separated by a one-week washout. The final doses were 75 mg for amitriptyline and 600 mg for carbamazepine (adjusted from 800 mg, because of side-effects). The effect of treatment was assessed by two daily ratings of pain using a 10- step verbal rating scale (VRS), and at the end of each treatment period using a 5-step global rating scale. For the assessment of depression the Comprehensive Psychopathological Rating Scale (CPRS) was used.

    Originally 23 patients were included in the study, but due to side-effects 7 patients discontinued during the amitriptyline phase, and 12 during the carbamazepine phase. With carbamazepine this occurred at low doses (100-200 mg).

    The results show that amitriptyline significantly reduced non-paroxysmal CP in MS, compared to placebo (VRS 4.2 vs. 5.3; p<0.05) and according to the global rating; nine of 14 patients were responders (64%). The effect could already be seen during the second week of treatment. The plasma concentrations of amitriptyline and its active metabolite nortriptyline were higher in the responders (329 nmol/l) that in the non-responders (252 nmol/l, n.s). CPRS scores for depression were normal, and were not altered by the medication.

    Two of nine patients treated with carbamazepine reported some pain relief, but the effect did not reach significance when compared with placebo. No correlation was found between effect and plasma concentration.

    It is concluded that amitriptyline, but not carbamazepine, has a weak effect on non-paroxysmal CP in MS, and that MS patients appear to be particularly sensitive to the side-effects of the two drugs.

  • 101441.
    Österberg, Anders
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    Boivie, Jörgen
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    Central pain in multiple sclerosis: sensory abnormalities2010In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 14, no 1, p. 104-110Article in journal (Refereed)
    Abstract [en]

    Many patients with multiple sclerosis (MS) develop central neuropathic pain (CP). In the present study somatosensory abnormalities have been analysed in detail in 62 patients with MS and CP (42 women, 20 men; mean age 52 years) and in a control group of 10 women and 6 men (mean age 47 years) with MS and sensory symptoms, but without pain.

    Assessment included clinical testing and quantitative methods (QST) for the measurement of perception thresholds for touch, vibration, and temperatures.

    All CP patients except two (97%) had abnormal thresholds for innoxious and/or noxious temperatures, compared to 81% in the control group (p < 0.05). There was a tendency towards the opposite regarding sensibility to touch, which was decreased in 66% vs. 87% (n.s.), vibration (55% vs. 81%; n.s.) and to joint movement (32% vs. 62%; p < 0.04).

    Comparisons between painful and non-painful regions showed both the absolute threshold values and the index values to be significantly more abnormal, in the CP regions, for warmth (p < 0.001), cold (p < 0.05), difference limen (innoxious warmth and cold, p < 0.01), cold pain (p < 0.01) and heat pain/cold pain combined (p < 0.001).

    Also the comparisons between regions with central pain and regions with sensory symptoms in the controls showed significantly more abnormal thresholds in the CP patients for warmth (p < 0.05), cold (p < 0.01), difference limen (innoxious warmth and cold, p < 0.01) and heat pain/cold pain combined (p < 0.001).

    The results support the general hypothesis that only patients who have lesions affecting the spinothalamo-cortical pathways run the risk of developing central pain.

  • 101442.
    Österberg, Anders
    et al.
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences.
    Boivie, Jörgen
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences.
    Thoumas, K-Å
    Linköping University, Department of Medicine and Care, Radiology. Linköping University, Faculty of Health Sciences.
    Central pain in multiple sclerosis: prevalence and clinical characteristics2005In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 9, no 5, p. 531-542Article in journal (Refereed)
    Abstract [en]

    Pain is more common in multiple sclerosis (MS) than has previously been recognised. In the present study we have investigated the occurrence of central pain (CP) in MS and defined its characteristics. Questionnaires were sent to all 429 patients with definite MS in the patient register at our neurology department. All admitting to pain were interviewed and offered an extended interview and examination. Three hundred and sixty four patients responded (86%), of whom 57.5% reported pain during the course of their disease (21% nociceptive, 2% peripheral neuropathic and 1% related to spasticity). One hundred patients (27.5%) had CP, including 18 patients (4.9%) with trigeminal neuralgia.

    The non-trigeminal CP was, in 87%, located in the lower and in 31% in the upper extremities. It was mostly bilateral (76%) and constant, with 88% experiencing daily pain. Only 2% had paroxysmal attacks. Aching, burning, pricking were the commonest qualities. The pain was intense with small to moderate spontaneous variation. In 5.5% of all patients (20% of the patients with CP), pain was a presenting symptom, alone or in combination with other symptoms.

    The most common neurological symptoms/signs besides CP were sensory abnormalities (98%, dominated by abnormal sensibility to painful stimulus and temperature). Trigeminal neuralgia in MS started later in life and after longer disease duration than non-trigeminal pain. Both types of CP existed either chronically or as a feature of relapse. Central pain is thus an important symptom in MS (around 30%) and causes much suffering.

  • 101443.
    Österberg, Anna
    Linköping University, Department of Management and Economics.
    Kommunal demokrati och medborgarinflytande i ett samhälle i förändring2002Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [en]

    The organisation of the municipalities is based on the principle of representation. It has previously been impossible to give the citizens more influence through direct democracy, but the information technology gives new possibilities and the choice of democracy model might no longer be obvious. Representation can be interpreted in many ways and there is a need for a more distinct definition of the rule that the municipalities shall be governed according to the principle of representation. It should also be further investigated how the new technology can be used to increase the use of direct democracy. The municipalities ought to work to supplement the representation with direct democracy in the form of active discourse with the citizens. This can be done for example through referendums, consultations or citizen councils. There are already possibilities to increase the civil influence, and the municipalities are therefore responsible to ensure that these possibilities are used.

  • 101444.
    Österberg, Annika
    et al.
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    Kvist, Joanna
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    Abrandt Dahlgren, Madeleine
    Linköping University, Department of Medical and Health Sciences, Medical Pedagogics. Linköping University, Faculty of Health Sciences.
    Ways of experiencing participation and factors affecting the activity level after nonreconstructed anterior cruciate ligament injury: a qualitative study2013In: Journal of Orthopaedic and Sports Physical Therapy, ISSN 0190-6011, E-ISSN 1938-1344, Vol. 43, no 3, p. 172-183Article in journal (Refereed)
    Abstract [en]

    STUDY DESIGN: Phenomenographic, cross-sectional. OBJECTIVES: To describe ways of experiencing participation in activities of individuals with a nonreconstructed anterior cruciate ligament injury and to describe the emotional aspects related to participation. Further, the objective was to explore factors affecting the activity level. BACKGROUND: The importance of assessing different factors (knee status, muscle performance, psychological factors, performance-based tests, and subjective rating of knee function) after an anterior cruciate ligament injury has been emphasized. However, the results of these assessments do not answer the question of how the individuals themselves experience their participation in activities. METHODS: Semi-structured interviews were conducted with 19 strategically selected informants (age range, 18-43 years) who had sustained an anterior cruciate ligament injury 18 to 67 months previously. A phenomenographic approach, which describes individuals' ways of experiencing a phenomenon, was used. RESULTS: Five qualitatively different categories were identified: (A) unconditioned participation, (B) participation as conditioned by risk appraisal, (C) participation as conditioned by experienced control of the knee, (D) participation as conditioned by experienced knee impairment, and (E) participation as conditioned by neglecting the knee injury. Within each category, 5 interrelated aspects were discerned: focus, level of performance, activities, strategies, and feelings. Categories A, C, and E reflected experiences of full participation, whereas categories B and D reflected experiences of modified participation. There were mostly positive feelings regarding participation. Negative feelings were expressed in category D. Factors affecting the activity level were grouped according to the framework of the International Classification of Functioning, Disability and Health and described as facilitating or hindering the activity level. Facilitating factors included regaining and maintaining physical function, regaining confidence in knee function, and learning/relearning movement patterns. Hindering factors included fear of injury/reinjury, uncontrollable giving way, and loss of motivation. CONCLUSION: With different strategies, most of the informants achieved a satisfactory activity level, despite impairments and decreased activity level. Both physical and psychological factors were described to affect the activity level, as well as time since injury.

  • 101445.
    Österberg, Annika
    et al.
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    Kvist, Joanna
    Linköping University, Department of Medical and Health Sciences, Physiotherapy. Linköping University, Faculty of Health Sciences.
    Abrandt Dahlgren, Madeleine
    Linköping University, Department of Medical and Health Sciences, Medical Pedagogics. Linköping University, Faculty of Health Sciences.
    Ways of experiencing participation and factors affecting the current activity level after non-reconstructed ACL injury2011Conference paper (Other academic)
    Abstract [en]

    Current assessment methods after an ACL injury do not consider how the individuals themselves experience their participation in activities or what factors they think have affected their current activity level.

  • 101446.
    Österberg, Emmy
    Linköping University, Department of Physics, Chemistry and Biology, Biotechnology. Linköping University, The Institute of Technology.
    Ro52: Structure and interactions of constructs of RING and B-box2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The ubiquitination process is vital to maintain the protein homeostasis in the cell. With high specificity it regulates degradation of proteins by tagging them with a small protein called ubiquitin. Four proteins are involved to perform the process and in this thesis one of these proteins is studied. This protein is called Ro52 and belongs to the TRIM protein family. It posses E3 ligase activity because of a N-terminal RING-domain and therefore it is responsible for the last step in the ubiquitination process. The structure of Ro52 is not totally solved and the function of the protein’s four domains is not fully understood.

    In this thesis three constructs of two domains from Ro52 (RING and B-box) is investigated by circular dichroism (CD), nuclear magnetic resonance (NMR) spectroscopy and auto-ubiquitination assay by Western blot. The goal was to gain deeper insight in structural and functional properties of these domains.

    In the end only two constructs were investigated because of time limitations. It was shown by NMR that one construct has similar structure as the wild type but lower stability, possibly due to shorter N-terminal region. Comparison of the results from CD measurements showed that the constructs were well structured but did not reveal any significant differences in secondary structure between the constructs. Functional analysis by Western blot encountered unexpected problems and no results were obtained.

    The current thesis provides a basis for further investigation of variant constructs jointly expressing the RING-B-box domains, and shows that even small changes may alter structure and stability in ways that might affect functional properties. 

  • 101447.
    Österberg, Frida
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    The visual impact of lamination2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This scientific study concerns the visual colour effect caused by the thin polyethylene coating extruded on printed packaging material. The origin of the phenomenon is discovered and characterised mathematically. CIE delta E 2000 theory is adapted in the research for mathematical judgement of visual difference. The report handles the procedure of defining the character of the visual distortion and a characterisation of the effect. In this process it discusses areas as dot gain, colour shift and production parameters. It as well covers the background of colour and printing science. The aim of the work is to create a model that predicts the visual effect of lamination in the proofing stage of the production.

  • 101448.
    Österberg, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Ekblom, Carl-David
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    USB 2.0 Audio device2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main task of this project were to develop, hardware and software that could stream audio data via USB 2.0. This project were based on XMOS, USB 2.0 design. In this project we have brought an idea to reality in the form of a finished product. This with verification help from engineers on Syncore technologies. Under the development process the functionality surrounding component databases, provided by Altium designer, were to be evaluated. To be mentioned is that Altium designer was the software used to develop the PCB in this project. After many hours spent developing, we finally got the hardware and software to behave in the way it was suppose to do. That is, to be able to stream audio data from a high-resolution source(PC/MAC/unit with S/PDIF out, maximum resolution 24-bit 192 kHz). This to both S/PDIF and analog stereo out via RCA-connectors. The sound quality from a possible subjective point of view is very good and we are happy with the result. We think that the functionality surrounding component databases are convenient in many applications. Not just the fact that you easily can generate an up to date pricing of all components used in a project, you can also shorten the development process. This because the developer don't have to recreate schematic symbols and footprints that has already been created. Which of course was the fundamental idea behind the database functionality. These are just a few examples of its advantages. To be considered is the fact that the administration surrounding the component databases can be very time consuming. To take full advantage of Altium designers functionalities we think that it needs a dedicated administrator that maintains the database repository.

  • 101449.
    Österberg, Martin
    Linköping University, Department of Computer and Information Science.
    Design av en användarvänlig Androidapplikation för trådlös kommunikation med Electronic Control Unit för bil eller testmiljö2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a study about software usability and information presen-tation in an Android application. The application is meant topresent the information coming being sent on the CAN buss ofa car or to listen to the messages being sent by just a few ECUconnected via a CAN buss. The study aims to evaluate the usabi-lity of the application based on an exploratory research method.The study was conducted using an iterative processes, where wefirst created a prototype. The prototype was then presented to anumber of users and they were asked to do a number of simpletasks within the application. We then used the feedback from thisexamination to improve the usability of the application. After thiswe did a second presentation of the application and compared itto the results to the results from the previous tests to see if wesucceeded in increasing the usability of the application.The first study tests showed that there were several weaknesses inthe application that we ourselves did not see. It showed that ourbackground was too prominent and that the text became hard toread, along with several other small things that we corrected. Wethen saw in our second tests that most parts of the applicationhad improved. There were still some parts of the application thatcould still use some development, and all people what differentthings in an application.

  • 101450.
    Österberg, Ouliana
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Kartläggning av en fastighets miljöpåverkan: Livscykelanalys av flerfamiljsfastigheten "Teodoliten"2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today's climate and environmental issues have now been up for discussion for quite long. Various environmental measures have been taken, but it is not always certain that those measures actually are for the better because of the complexity of our environment. Therefore, studies of whole life cycles are very important even if they are time and resource intensive.

    Real estate accounts for 15% of global carbon emissions, but also affects our environment in many other aspects. In Sweden this number is even higher. About 30 % of its carbon dioxide emissions originates from building sector and changes are therefore of great importance. ByggVesta is a real estate company that wants to be at the forefront when it comes to eco-smart construction and wanted to know how well they are doing. It was therefore desired to conduct this LCA that reviewed their (by February 2012) newest completed property "Teodoliten" in Farsta, Stockholm.

    This life cycle assessment was a screening LCA i.e. it was carried out very superficially in order to identify the biggest polluters. All results were related to the functional unit of 1m2 floor area and year. It was found that the maintenance phase was the most pollutant one because of use of electricity and water. Here it can be mentioned that the electricity consumption is of Swedish electricity mix-type, which is much cleaner than many of the European mixes. It is therefore possible that the results may have been different if Teodoliten had been placed at another location.

    Among all the materials in the property, it was found that concrete elements were the worst pollutants. This report has, however, showed that the longer expected life time, the better this concrete frame is in comparison to wooden frame. If the property will be standing for 100 years, it will emit 95 % of the carbon dioxide- eqv. compared to a wooden frame that stands for only 60 years (the amount that is feasible for a wooden framed house). Although the climate aspect is the most focused one, the other environmental aspects show more clearly the benefits of concrete in long time perspective.

    ByggVesta has also been criticized for their shipments of concrete over the Baltic Sea. However, it has been shown that the transport with a cargo ship corresponds to only 23km by truck. Transport itself is therefore not considered to be a major subject for criticism. Latvian concrete production is of greater interest since the manufacturing process there might differ a lot from Swedish production and have other impact on environment. This issue could not be considered within the scope of this work.

    Shortly, this analysis shows that concrete frames and transportation with cargo ship is preferable if a building like Teodoliten is considered, with its geographical location and if its lifetime will last for 100 years as ByggVesta predicts. However, to be fully sure of the accuracy of these results it might be good to conduct a full comparative LCA on construction materials.

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