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  • Public defence: 2017-11-22 13:00 Belladonna, Linköping
    Blomgran, Parmis
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Inflammation and tendon healing2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Tendons heal through three different overlapping phases; the inflammatory, proliferative and remodeling phase. Many studies have investigated what factors influence healing of tendons. However, little was known about inflammation and the immune cells present during Achilles tendon healing by the time this thesis started. We developed a flow cytometry method for our rat model of tendon healing, which enabled us to study different leukocyte subpopulations during Achilles tendon healing.

    The general aim of this thesis was to understand more about inflammation and the immune cell populations present during tendon healing and how the immune cell composition changes during normal tendon healing. Moreover, we investigated how different factors that are known to influence tendon healing affected the composition of the immune cell population.

    First, we described the immune cells during the time course of tendon healing focusing on different subpopulations of macrophages and T cells. Then, we studied how these cells were influenced by reduced mechanical loading. Mechanical loading prolonged the presence of M1 macrophages and delayed the switch to regulatory T cells and M2 macrophages compared to reduced mechanical loading. Next, the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on the leukocyte composition revealed that, even though NSAIDs influence the mechanical properties of healing tendon, this effect was not mediated via changes in the leukocyte sub-populations during early and mid-time tendon healing. Further, the effect of corticosteroids during the inflammatory and remodeling phases of tendon healing was an improved healing of tendons and a reduction of CD8a T cells when corticosteroid was administered after the inflammatory phase. Lastly, we investigated if impairment of tendon healing by NSAIDs was related to mechanotransduction or microdamage during mechanical loading and showed that NSAIDs impair tendon healing by reducing the response to microdamage.

    In conclusion, these studies show that inflammation plays an important role during Achilles tendon healing, and factors that influence healing can also alter the presence or polarization of immune cell populations. 

    List of papers
    1. A possible link between loading, inflammation and healing: Immune cell populations during tendon healing in the rat
    Open this publication in new window or tab >>A possible link between loading, inflammation and healing: Immune cell populations during tendon healing in the rat
    2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, no 29824Article in journal (Refereed) Published
    Abstract [en]

    Loading influences tendon healing, and so does inflammation. We hypothesized that the two are connected. 48 rats underwent Achilles tendon transection. Half of the rats received Botox injections into calf muscles to reduce mechanical loading. Cells from the regenerating tissue were analyzed by flow cytometry. In the loaded group, the regenerating tissue contained 83% leukocytes (CD45(+)) day 1, and 23% day 10. The M1/M2 macrophage ratio (CCR7/CD206) peaked at day 3, while T helper (CD3(+)CD4(+)) and T-reg cells (CD25(+) Foxp3(+)) increased over time. With Botox, markers associated with down-regulation of inflammation were more common day 5 (CD163, CD206, CD25, Foxp3), and M1 or M2 macrophages and T-reg cells were virtually absent day 10, while still present with full loading. The primary variable, CCR7/CD206 ratio day 5, was higher with full loading (p = 0.001) and the T-reg cell fraction was lower (p amp;lt; 0.001). Free cage activity loading is known to increase size and strength of the tendon in this model compared to Botox. Loading now appeared to delay the switch to an M2 type of inflammation with more T-reg cells. It seems a prolonged M1 phase due to loading might make the tendon regenerate bigger.

    Place, publisher, year, edition, pages
    NATURE PUBLISHING GROUP, 2016
    National Category
    Cell and Molecular Biology
    Identifiers
    urn:nbn:se:liu:diva-130383 (URN)10.1038/srep29824 (DOI)000379584000001 ()27405922 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [K2013-52X-02031-47-5]; Swedish National Centre for Research in Sports; King Gustaf V and Queen Victoria Free Mason Foundation

    Available from: 2016-08-15 Created: 2016-08-05 Last updated: 2017-10-30
    2. Cox-2 inhibition and the composition of inflammatory cell populations during early and mid-time tendon healing
    Open this publication in new window or tab >>Cox-2 inhibition and the composition of inflammatory cell populations during early and mid-time tendon healing
    2017 (English)In: Muscles, ligaments and Tendons journal, ISSN 2240-4554, Vol. 7, no 2, 223-229 p.Article in journal (Refereed) Published
    Abstract [en]

    Background: During early tendon healing, the cells within the regenerating tissue are, to a large part, inflammatory leukocytes (CD45+). In a rat Achilles tendon healing model, the inflammation resolves between 5 and 10 days. In the same model, Cox inhibitors (NSAIDs) impair healing when given during the first 5 days, but have a positive effect if given later. We tested the hypothesis that a Cox inhibitor would exert these effects by influencing inflammation, and thereby the composition of the inflammatory cell subpopulations.Methods: Achilles tendon transection was performed in 44 animals. Animals were randomized to either parecoxib or saline injections. Healing was evaluated by mechanical testing day 7 after surgery and by flow cytometry day 3 and 10.Results: Cross-sectional area, peak force and stiffness were reduced by parecoxib 31, 33, and 25% respectively (p=0.005, p=0.002, and p=0.005). By flow cytometry, there was a strong effect of time (p<0.001) on virtually all inflammatory cell subpopulations (CD45, CD11b, CD68, CCR7, CD163, CD206, CD3, CD4), but no significant effect of parecoxib at any time point.Conclusion: The results suggest that the negative effects of Cox inhibitors on tendon healing might be exerted mainly via mechanisms not directly related to inflammatory cells.

    Place, publisher, year, edition, pages
    Rome, Italy: CIC Edizioni Internazionali, 2017
    Keyword
    tendon healing; NSAID; inflammation; rat model; flow cytometry
    National Category
    Pharmacology and Toxicology
    Identifiers
    urn:nbn:se:liu:diva-142352 (URN)
    Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2017-10-30
    3. Systemic corticosteroids improve tendon healing when given after the early inflammatory phase
    Open this publication in new window or tab >>Systemic corticosteroids improve tendon healing when given after the early inflammatory phase
    2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, 12468Article in journal (Refereed) Published
    Abstract [en]

    Inflammation initiates tendon healing and then normally resolves more or less completely. Unresolved inflammation might disturb the remodeling process. We hypothesized that suppression of inflammation during the early remodeling phase by systemic dexamethasone treatment can improve healing. 36 rats underwent Achilles tendon transection and were randomized to dexamethasone or saline on days 0-4 after surgery (early inflammatory phase), and euthanasia day 7. Another 54 rats received injections days 5-9 (early remodeling phase) and were euthanized day 12 for mechanical, histological and flow cytometric evaluation. Dexamethasone treatment days 0-4 reduced the cross-sectional area, peak force and stiffness by day 7 to less than half (p amp;lt; 0.001 for all), while material properties (peak stress and elastic modulus) were not significantly affected. In contrast, dexamethasone treatment days 5-9 increased peak force by 39% (p = 0.002) and stiffness by 58% (p amp;lt; 0.001). The cross-sectional area was reduced by 42% (p amp;lt; 0.001). Peak stress and elastic modulus were more than doubled (p amp;lt; 0.001 for both). Semi-quantitative histology at day 12 showed that late dexamethasone treatment improved collagen alignment, and flow cytometry revealed reduced numbers of CD8a(+) cytotoxic T cells in the tendon callus. These results suggest that downregulation of lingering inflammation during the early remodeling phase can improve healing.

    Place, publisher, year, edition, pages
    NATURE PUBLISHING GROUP, 2017
    National Category
    Biomaterials Science
    Identifiers
    urn:nbn:se:liu:diva-142175 (URN)10.1038/s41598-017-12657-0 (DOI)000412032600034 ()28963482 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [K2013-52X-02031-47-5]; Swedish National Centre for Research in Sports; Ostergotland county (ALF)

    Available from: 2017-10-23 Created: 2017-10-23 Last updated: 2017-11-16
    4. COX-2 inhibition impairs mechanical stimulation of early tendon healing in rats by reducing the response to microdamage
    Open this publication in new window or tab >>COX-2 inhibition impairs mechanical stimulation of early tendon healing in rats by reducing the response to microdamage
    2015 (English)In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 119, no 5, 534-540 p.Article in journal (Refereed) Published
    Abstract [en]

    Early tendon healing can be stimulated by mechanical loading and inhibited by cyclooxygenase (COX) inhibitors (nonsteroidal anti-inflammatory drugs). Therefore, we investigated if impairment of tendon healing by a COX-2 inhibitor (parecoxib) is related to loading. Because loading might infer microdamage, which also stimulates healing, we also investigated if this effect is inhibited by parecoxib. The Achilles tendon was transected in 114 rats. Three degrees of loading were used: full loading, partial unloading, and unloading (no unloading, Botox injections in the plantar flexor muscles, or Botox in combination with tail suspension). For each loading condition, the rats received either parecoxib or saline. In a second experiment, rats were unloaded with Botox, and the tendon was subjected to microdamage by needling combined with either saline or parecoxib. Mechanical testing day 7 showed that there was a significant interaction between loading and parecoxib for peak force at failure (P less than 0.01). However, logarithmic values showed no significant interaction, meaning that we could not exclude that the inhibitory effect of parecoxib was proportionate to the degree of loading. Microbleeding was common in the healing tissue, suggesting that loading caused microdamage. Needling increased peak force at failure (P less than 0.01), and this effect of microdamage was almost abolished by parecoxib (P less than 0.01). Taken together, this suggests that COX-2 inhibition impairs the positive effects of mechanical loading during tendon healing, mainly by reducing the response to microdamage.

    Place, publisher, year, edition, pages
    AMER PHYSIOLOGICAL SOC, 2015
    Keyword
    tendon healing; COX-2; NSAIDs; mechanical stimulation; microdamage
    National Category
    Physiology Pharmacology and Toxicology
    Identifiers
    urn:nbn:se:liu:diva-122063 (URN)10.1152/japplphysiol.00239.2015 (DOI)000360694300013 ()26159755 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [K2013-52X-02031-47-5]; Swedish National Centre for Research in Sports; King Gustaf V and Queen Victoria Free Mason Foundation

    Available from: 2015-12-18 Created: 2015-10-19 Last updated: 2017-10-30
  • Public defence: 2017-11-23 13:00 VAL, Hus Vallfarten, Linköping
    Vernmark, Kristofer
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Therapeutic alliance and different treatment formats when delivering internet-based CBT for depression2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Depression is a debilitating disorder that affects a large part of the adult population every year. Yet there is still a lack of access to effective care for people in need. Cognitive Behaviour therapy (CBT) is an evidence-based method for treating depression that together with the increased availability of Internet services provides an opportunity to increase access to effective treatment. Internet-based interventions can be effective in the treatment of depression, but there is a lack of knowledge concerning which formats of delivery that can be used and if therapeutic alliance is of equal importance when providing treatment over the Internet. The overall aim of this thesis was to examine the effects of different treatment formats (email therapy, guided self-help, and blended treatment) in internet-based CBT for depression and to further examine the role of alliance in these treatment modalities.

    Findings from this thesis show that email therapy and internetbased treatment programs were effective methods for treating depression. Alliance ratings were high, showing that a positive therapeutic alliance can be achieved in internet-based treatments. Patient-rated alliance could not predict outcome in any of the different treatment formats. However, therapist-rated alliance predicted change in depression during blended treatment. This thesis includes the first randomized controlled study on CBTbased email therapy, and the first internet-based behavioral activation program with ACT-components, for adult depression.

    List of papers
    1. Internet administered guided self-help versus individualized e-mail therapy: A randomized trial of two versions of CBT for major depression
    Open this publication in new window or tab >>Internet administered guided self-help versus individualized e-mail therapy: A randomized trial of two versions of CBT for major depression
    Show others...
    2010 (English)In: BEHAVIOUR RESEARCH AND THERAPY, ISSN 0005-7967, Vol. 48, no 5, 368-376 p.Article in journal (Refereed) Published
    Abstract [en]

    Internet-delivered psychological treatment of major depression has been investigated in several trials, but the role of personalized treatment is less investigated. Studies suggest that guidance is important and that automated computerized programmes without therapist support are less effective. Individualized e-mail therapy for depression has not been studied in a controlled trial. Eighty-eight individuals with major depression were randomized to two different forms of Internet-delivered cognitive behaviour therapy (CBT), or to a waiting-list control group. One form of Internet treatment consisted of guided self-help, with weekly modules and homework assignments. Standard CBT components were presented and brief support was provided during the treatment. The other group received e-mail therapy, which was tailored and did not use the self-help texts i.e., all e-mails were written for the unique patient. Both treatments lasted for 8 weeks. In the guided self-help 93% completed (27/29) and in the e-mail therapy 96% (29/30) completed the posttreatment assessment. Results showed significant symptom reductions in both treatment groups with moderate to large effect sizes. At posttreatment 34.5% of the guided self-help group and 30% of the e-mail therapy group reached the criteria of high-end-state functioning (Beck Depression Inventory score below 9). At six-month follow-up the corresponding figures were 47.4% and 43.3%. Overall, the difference between guided self-help and e-mail therapy was small, but in favour of the latter. These findings indicate that both guided self-help and individualized e-mail therapy can be effective.

    Place, publisher, year, edition, pages
    Elsevier Science B.V., Amsterdam., 2010
    Keyword
    Internet treatment, Major depression, E-mail therapy, Guided self-help
    National Category
    Social Sciences
    Identifiers
    urn:nbn:se:liu:diva-57417 (URN)10.1016/j.brat.2010.01.005 (DOI)000278168000003 ()
    Available from: 2010-06-18 Created: 2010-06-18 Last updated: 2017-10-30
    2. Therapeutic alliance in guided internet-delivered cognitive behavioural treatment of depression, generalized anxiety disorder and social anxiety disorder
    Open this publication in new window or tab >>Therapeutic alliance in guided internet-delivered cognitive behavioural treatment of depression, generalized anxiety disorder and social anxiety disorder
    Show others...
    2012 (English)In: Behaviour Research and Therapy, ISSN 0005-7967, E-ISSN 1873-622X, Vol. 50, no 9, 544-550 p.Article in journal (Refereed) Published
    Abstract [en]

    Guided internet-delivered cognitive behaviour therapy (ICBT) has been found to be effective in several controlled trials, but the mechanisms of change are largely unknown. Therapeutic alliance is a factor that has been studied in many psychotherapy trials, but the role of therapeutic alliance in ICBT is less well known. The present study investigated early alliance ratings in three separate samples. Participants from one sample of depressed individuals (N = 49), one sample of individuals with generalized anxiety disorder (N = 35), and one sample with social anxiety disorder (N = 90) completed the Working Alliance Inventory (WAI) modified for ICBT early in the treatment (weeks 3-4) when they took part in guided ICBT for their conditions. Results showed that alliance ratings were high in all three samples and that the WAI including the subscales of Task, Goal and Bond had high internal consistencies. Overall, correlations between the WAI and residualized change scores on the primary outcome measures were small and not statistically significant. We conclude that even if alliance ratings are in line with face-to-face studies, therapeutic alliance as measured by the WAI is probably less important in ICBT than in regular face-to-face psychotherapy.

    Place, publisher, year, edition, pages
    Elsevier, 2012
    National Category
    Social Sciences
    Identifiers
    urn:nbn:se:liu:diva-79399 (URN)10.1016/j.brat.2012.05.003 (DOI)000307909100003 ()22728647 (PubMedID)
    Available from: 2012-07-16 Created: 2012-07-16 Last updated: 2017-10-30Bibliographically approved
    3. Internet-based behavioral activation and acceptance-based treatment for depression: A randomized controlled trial
    Open this publication in new window or tab >>Internet-based behavioral activation and acceptance-based treatment for depression: A randomized controlled trial
    Show others...
    2013 (English)In: Journal of Affective Disorders, ISSN 0165-0327, E-ISSN 1573-2517, Vol. 148, no 2-3, 331-337 p.Article in journal (Refereed) Published
    Abstract [en]

    Background: Internet-based cognitive behavior therapy for depression has been tested in several trials but there are no internet studies on behavioral activation (BA), and no studies on BA over the internet including components of acceptance and commitment therapy (ACT). The aim of this study was to develop and test the effects of internet-delivered BA combined with ACT against a waiting list control condition as a first test of the effects of treatment. less thanbrgreater than less thanbrgreater thanMethods: Selection took place with a computerized screening interview and a subsequent semi-structured telephone interview. A total of 80 individuals from the general public were randomized to one of two conditions. The treatment lasted for 8 weeks after which both groups were assessed. We also included a 3 month follow-up. The treatment included interactive elements online and a CD-ROM for mindfulness and acceptance exercises. In addition, written support and feedback was given by a therapist every week. less thanbrgreater than less thanbrgreater thanResults: Results at posttreatment showed a large between group effect size on the Beck Depression inventory II d = 0.98 (95%CI = 0.51-1.44). In the treated group 25% (10/40) reached remission defined as a BDI score andlt;= 10 vs. 5% (2/40) in the control group. Results on secondary measures were smaller. While few dropped out from the study (N = 2) at posttreatment, the average number of completed modules was M = 5.1 out of the seven modules. less thanbrgreater than less thanbrgreater thanLimitations: The study only included a waiting-list comparison and it is not possible to determine which treatment components were the most effective. less thanbrgreater than less thanbrgreater thanConclusions: We conclude that there is initial evidence that BA with components of ACT can be effective in reducing symptoms of depression.

    Place, publisher, year, edition, pages
    Elsevier, 2013
    Keyword
    Depression, Internet-based treatment, Acceptance and commitment therapy, Randomized controlled trial
    National Category
    Social Sciences
    Identifiers
    urn:nbn:se:liu:diva-94601 (URN)10.1016/j.jad.2012.12.020 (DOI)000318909700024 ()
    Note

    Funding Agencies|Swedish Science Foundation||Swedish Council for Social Research||Swedish Council for Work Life Research||

    Available from: 2013-06-27 Created: 2013-06-27 Last updated: 2017-10-30
  • Public defence: 2017-11-24 10:00 Planck, Fysikhuset, Linköping
    Niklasson, Markus
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Coding to cure: NMR and thermodynamic software applied to congenital heart disease research2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Regardless of scientific field computers have become pivotal tools for data analysis and the field of structural biology is not an exception. Here, computers are the main tools used for tasks including structural calculations of proteins, spectral analysis of nuclear magnetic resonance (NMR) spectroscopy data and fitting mathematical models to data. As results reported in papers heavily rely on software and scripts it is of key importance that the employed computational methods are robust and yield reliable results. However, as many scientific fields are niched and possess a small potential user base the task to develop necessary software often falls on researchers themselves. This can cause divergence when comparing data analyzed by different measures or by using subpar methods. Therein lies the importance of development of accurate computational methods that can be employed by the scientific community.

    The main theme of this thesis is software development applied to structural biology, with the purpose to aid research in this scientific field by speeding up the process of data analysis as well as to ensure that acquired data is properly analyzed. Among the original results of this thesis are three user-friendly software:

    COMPASS - a resonance assignment software for NMR spectroscopy data capable of analyzing chemical shifts and providing the user with suggestions to potential resonance assignments, based on a meticulous database comparison.

    CDpal - a curve fitting software used to fit thermal and chemical denaturation data of proteins acquired by circular dichroism (CD) spectroscopy or fluorescence spectroscopy.

    PINT - a line shape fitting and downstream analysis software forNMRspectroscopy data, designed with the important purpose to easily and accurately fit peaks in NMR spectra and extract parameters such as relaxation rates, intensities and volumes of peaks.

    This thesis also describes a study performed on variants of the life essential regulatory protein calmodulin that have been associated with the congenital life threatening heart disease long QT syndrome (LQTS). The study provided novel insights revealing that all variants are distinct from the wild type in regards to structure and dynamics on a detailed level; the presented results are useful for the interpretation of results from protein interaction studies. The underlying research of this paper makes use of all three developed software, which validates that all developed methods fulfil a scientific purpose and are capable of producing solid results.

    List of papers
    1. Fast and Accurate Resonance Assignment of Small-to-Large Proteins by Combining Automated and Manual Approaches
    Open this publication in new window or tab >>Fast and Accurate Resonance Assignment of Small-to-Large Proteins by Combining Automated and Manual Approaches
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    2015 (English)In: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 11, no 1, e1004022- p.Article in journal (Refereed) Published
    Abstract [en]

    The process of resonance assignment is fundamental to most NMR studies of protein structure and dynamics. Unfortunately, the manual assignment of residues is tedious and time-consuming, and can represent a significant bottleneck for further characterization. Furthermore, while automated approaches have been developed, they are often limited in their accuracy, particularly for larger proteins. Here, we address this by introducing the software COMPASS, which, by combining automated resonance assignment with manual intervention, is able to achieve accuracy approaching that from manual assignments at greatly accelerated speeds. Moreover, by including the option to compensate for isotope shift effects in deuterated proteins, COMPASS is far more accurate for larger proteins than existing automated methods. COMPASS is an open-source project licensed under GNU General Public License and is available for download from http://www.liu.se/forskning/foass/tidigare-foass/patrik-lundstrom/software?l=en. Source code and binaries for Linux, Mac OS X and Microsoft Windows are available.

    Place, publisher, year, edition, pages
    Public Library of Science, 2015
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-115010 (URN)10.1371/journal.pcbi.1004022 (DOI)000349309400013 ()25569628 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [Dnr. 2012-5136]

    Available from: 2015-03-09 Created: 2015-03-06 Last updated: 2017-11-03
    2. Robust and convenient analysis of protein thermal and chemical stability
    Open this publication in new window or tab >>Robust and convenient analysis of protein thermal and chemical stability
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    2015 (English)In: Protein Science, ISSN 0961-8368, E-ISSN 1469-896X, Vol. 24, no 12, 2055-2062 p.Article in journal (Refereed) Published
    Abstract [en]

    We present the software CDpal that is used to analyze thermal and chemical denaturation data to obtain information on protein stability. The software uses standard assumptions and equations applied to two-state and various types of three-state denaturation models in order to determine thermodynamic parameters. It can analyze denaturation monitored by both circular dichroism and fluorescence spectroscopy and is extremely flexible in terms of input format. Furthermore, it is intuitive and easy to use because of the graphical user interface and extensive documentation. As illustrated by the examples herein, CDpal should be a valuable tool for analysis of protein stability.

    Place, publisher, year, edition, pages
    WILEY-BLACKWELL, 2015
    Keyword
    protein stability; thermal denaturation; chemical denaturation; circular dichroism; fluorescence; curve fitting; protein stability software; protein denaturation software
    National Category
    Chemical Sciences Clinical Medicine
    Identifiers
    urn:nbn:se:liu:diva-124648 (URN)10.1002/pro.2809 (DOI)000368292000014 ()26402034 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [2012-5136]; LiU Cancer

    Available from: 2016-02-08 Created: 2016-02-08 Last updated: 2017-11-03
    3. Comprehensive analysis of NMR data using advanced line shape fitting.
    Open this publication in new window or tab >>Comprehensive analysis of NMR data using advanced line shape fitting.
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    2017 (English)In: Journal of Biomolecular NMR, ISSN 0925-2738, E-ISSN 1573-5001, Vol. 69, no 2, 93-99 p.Article in journal (Refereed) Published
    Abstract [en]

    NMR spectroscopy is uniquely suited for atomic resolution studies of biomolecules such as proteins, nucleic acids and metabolites, since detailed information on structure and dynamics are encoded in positions and line shapes of peaks in NMR spectra. Unfortunately, accurate determination of these parameters is often complicated and time consuming, in part due to the need for different software at the various analysis steps and for validating the results. Here, we present an integrated, cross-platform and open-source software that is significantly more versatile than the typical line shape fitting application. The software is a completely redesigned version of PINT ( https://pint-nmr.github.io/PINT/ ). It features a graphical user interface and includes functionality for peak picking, editing of peak lists and line shape fitting. In addition, the obtained peak intensities can be used directly to extract, for instance, relaxation rates, heteronuclear NOE values and exchange parameters. In contrast to most available software the entire process from spectral visualization to preparation of publication-ready figures is done solely using PINT and often within minutes, thereby, increasing productivity for users of all experience levels. Unique to the software are also the outstanding tools for evaluating the quality of the fitting results and extensive, but easy-to-use, customization of the fitting protocol and graphical output. In this communication, we describe the features of the new version of PINT and benchmark its performance.

    Place, publisher, year, edition, pages
    Springer, 2017
    Keyword
    Dynamics, Line shape fitting, Peak integration, Relaxation, Spectral analysis
    National Category
    Biochemistry and Molecular Biology Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-142786 (URN)10.1007/s10858-017-0141-6 (DOI)000414206400004 ()29043470 (PubMedID)
    Note

    Funding agencies: Swedish Research Council [2012-5136]

    Available from: 2017-11-03 Created: 2017-11-03 Last updated: 2017-11-20
  • Public defence: 2017-11-24 10:15 A24, A-huset, Linköping
    Carlsson, Inga-Lill
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering.
    Towards System Supply: Development of Small and Medium-Sized Contract Manufacturers2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One way for a small subcontractor to meet increasing global competition is to develop a system supplying ability, implying a transition in the supply chain toward a larger overall responsibility. As large corporations outsource parts of their manufacturing and services, many small and medium-sized enterprise (SME) suppliers are expected to deepen their capabilities and take on the role of system suppliers. The overall purpose of this thesis is to advance the understanding of how SME contract manufacturers can develop such capabilities, identifying demands and abilities in various steps of this process. The research approach is based on the resource-based view.

    This longitudinal case study of an SME supplier striving to become a system supplier covers the period from 2006 to 2014. The researcher’s role as business developer and member of the management made it possible to follow the company's development continuously and closely, providing access to relevant internal data complemented with internal and external semi structured interviews and focus discussions. The longitudinal aspect is evident in the overall description of the development of the focal supplier. More specific issues are covered in the separate studies, described in the appended articles.

    SME suppliers need basic capabilities of qualitative production performance as stepping-stones to develop more system supplier capabilities for added customer value. Development of stable production processes through lean implementation was by the focal supplier seen as a way to reach stable basic performance and to enable continuous development. The study further shows that knowledge integration with customers is an effective means to build system capability and indicates a stepwise and sequential process of developing specific supplier capabilities.

    The longitudinal case study deepens the knowledge of development of SME system suppliers and specifically point out three prerequisites that need to be in place for the supplier transition: (1) a capability of the supplier to manage internal processes of standardisation and continuous improvements for stable performance without disruptions, (2) a capability to collaborate in development projects with a limited number of customers, and (3) customer commitment to a long-term relationship. A customer demanding improvements is constantly driving its suppliers to better performance and proven supplier capabilities in turn promotes long-term customer commitment. The most essential component in supplier development is a competent and strategically oriented management, capable of identifying the specific system supplier offerings appropriate for the particular company in order to create customer value.

    This study contributes to better understanding of the conditions of medium-sized contract manufacturing SMEs, from a supplier perspective, and contributes to SCM research in illustrating how shifting responsibilities and subsequent activities in the supply chain may pave new competitive paths for SMEs. One issue here is the importance of knowledge integration for the development of supply chains. This has not often been discussed within SCM and thus provides a contribution to this theory.  

    List of papers
    1. Towards system capability: identifying logistics and manufacturing demands for small suppliers
    Open this publication in new window or tab >>Towards system capability: identifying logistics and manufacturing demands for small suppliers
    2007 (English)In: Proceedings of 14th EurOMA Conference in Ankara, 17-20 June, 2007, 2007, 2007Conference paper, Published paper (Refereed)
    National Category
    Economics and Business
    Identifiers
    urn:nbn:se:liu:diva-139585 (URN)9789756090237 (ISBN)
    Conference
    14th International Annual EurOMA Conference, Ankara, Turkey, June 17-20, 2007
    Available from: 2017-08-09 Created: 2017-08-09 Last updated: 2017-10-26
    2. Resources to Form Logistics Capabilities: from the Perspective of a Small- or Medium-Sized Subcontractor
    Open this publication in new window or tab >>Resources to Form Logistics Capabilities: from the Perspective of a Small- or Medium-Sized Subcontractor
    2008 (English)In: Supply Chain Forum: an International Journal, ISSN 1625-8312, E-ISSN 1624-6039, Vol. 9, no 2, 6-15 p.Article in journal (Refereed) Published
    Abstract [en]

    One way for a small subcontractor to meet increasing global competitionis to develop a system supplying ability, which implies more focus onlogistical issues and a larger overall responsibility in the supply chain.Certain logistics capabilities have been identified as important to a smallormedium-sized subcontractor in order to cope with the systemsupplying role. Interviews have been carried out in a multiple case studywith the purpose of identifying important resources for a smaller supplierwith the ambition of forming logistics capabilities to support systemsupply. Resources within three different areas have been identified:organizational, competence base, and tools. Conclusions from acomparison among three companies, with different degrees of systemsupplying services, point out the importance of an organization with clearand distinct responsibilities and authorities. Competencies in logistics andenhanced understanding and use of IT support and communicationsystems are identified as areas to improve for the smaller companies.

    Place, publisher, year, edition, pages
    Taylor & Francis, 2008
    National Category
    Economics and Business
    Identifiers
    urn:nbn:se:liu:diva-139586 (URN)10.1080/16258312.2008.11517195 (DOI)
    Available from: 2017-08-09 Created: 2017-08-09 Last updated: 2017-10-26
    3. Investing in Lean to Improve Basic Capabilities: A strategy for System Supply?
    Open this publication in new window or tab >>Investing in Lean to Improve Basic Capabilities: A strategy for System Supply?
    2017 (English)In: Journal of Industrial Engineering and Management, ISSN 2013-8423, E-ISSN 2013-0953, Vol. 10, no 1, 28-48 p.Article in journal (Refereed) Published
    Abstract [en]

    Purpose: This paper describes the perceived effects of implementing lean production in aSwedish SME contract manufacturer. Especially focused are the effects on, and possible tradeoffsbetween, cost-efficiency and flexibility.Design/methodology/approach: SME suppliers need basic capabilities of qualitativeproduction performance as stepping-stones to develop more system supplier capabilities foradded customer value. Development of stable production processes is seen as a way to reachstable basic performance, efficient and with higher resource utilization. Quality is a precursor todelivery performance as well as to cost reduction and flexibility. This is a longitudinal single casestudy of a SME supplier striving to become a system supplier. Two main sources of datacollection are used: interviews and the main author’s presence as employee and businessdeveloper, participating in and following up the ongoing change process.Findings: Analyzing the development over time illustrated the importance of context andcontent for the change process. Two specific findings appeared: (1) An initial effect was animportant “eye-opener” for the balance between cost efficiency and flexibility in the organization.(2) Process orientation, as the basis of both lean and agile approaches, allows many improvementswithout any conflicts or trade-offs between these two goals. Stability in the production leads to increased controllability, initially resulting in both higher cost-efficiency and higher flexibility. Asthe organization develops however, strategic considerations relating to the chosen market strategymight occur: cost leadership or differentiation.Research limitations/implications: These results reflect the experiences of one SME supplierand further studies are needed for generalizability.Originality/value: The study increases the understanding of how a SME may develop stableprocesses in its different supplier-customer contexts. The study points at some necessary basiccomponents of this process approach as a first step for the transition to system supplier.

    Place, publisher, year, edition, pages
    Omnia Publisher SL, 2017
    Keyword
    SME, system supplier capability, lean production, agility, stable processes
    National Category
    Economics and Business
    Identifiers
    urn:nbn:se:liu:diva-139587 (URN)10.3926/jiem.2163 (DOI)
    Available from: 2017-08-09 Created: 2017-08-09 Last updated: 2017-10-26
    4. Developing system supplier capability by integrating knowledge with customers
    Open this publication in new window or tab >>Developing system supplier capability by integrating knowledge with customers
    2017 (English)In: International Journal of Logistics Systems and Management, ISSN 1742-7967, E-ISSN 1742-7975Article in journal (Refereed) Accepted
    Place, publisher, year, edition, pages
    InderScience Publishers, 2017
    National Category
    Economics and Business
    Identifiers
    urn:nbn:se:liu:diva-139588 (URN)
    Available from: 2017-08-09 Created: 2017-08-09 Last updated: 2017-10-26
  • Public defence: 2017-11-24 13:00 Berzeliussalen, Linköping
    Ahle, Margareta
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Necrotising Enterocolitis: epidemiology and imaging2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Necrotising enterocolitis (NEC) is a potentially devastating intestinal inflammation of multifactorial aetiology in premature or otherwise vulnerable neonates. Because of the broad spectrum of presentations, diagnosis and timing of surgical intervention may be challenging, and imaging needs to be an integrated part of management.

    The first four studies included in this thesis used routinely collected, nationwide register data to describe the incidence of NEC in Sweden 1987‒2009, its variation with time, seasonality, space-time clustering, and associations with maternal, gestational, and perinatal factors, and the risk of intestinal failure in the aftermath of the disease.

    Early infant survival increased dramatically during the study period. The incidence rate of NEC was 0.34 per 1,000 live births, rising from 0.26 per 1,000 live births in the first six years of the study period to 0.57 in the last five. The incidence rates in the lowest birth weights were 100‒160 times those of the entire birth cohort. Seasonal variation was found, as well as space-time clustering in association with delivery hospitals but not with maternal residential municipalities.

    Comparing NEC cases with matched controls, some factors, positively associated with NEC, were isoimmunisation, fetal distress, caesarean section, persistent ductus arteriosus, cardiac and gastrointestinal malformations, and chromosomal abnormalities. Negative associations included maternal pre-eclampsia, maternal urinary infection, and premature rupture of the membranes. Intestinal failure occurred in 6% of NEC cases and 0.4% of controls, with the highest incidence towards the end of the study period.

    The last study investigated current practices and perceptions of imaging in the management of NEC, as reported by involved specialists. There was great consensus on most issues. Areas in need of further study seem mainly related to imaging routines, the use of ultrasound, and indications for surgery.

    Developing alongside the progress of neonatal care, NEC is a complex, multifactorial disease, with shifting patterns of predisposing and precipitating causes, and potentially serious long-term complications. The findings of seasonal variation, spacetime clustering, and negative associations with antenatal exposure to infectious agents, fit into the growing understanding of the central role of bacteria and immunological processes in normal maturation of the intestinal canal as well as in the pathogenesis of NEC. Imaging in the management of NEC may be developed through future studies combining multiple diagnostic parameters in relation to clinical outcome.

    List of papers
    1. Epidemiology and Trends of Necrotizing Enterocolitis in Sweden: 1987-2009
    Open this publication in new window or tab >>Epidemiology and Trends of Necrotizing Enterocolitis in Sweden: 1987-2009
    2013 (English)In: Pediatrics, ISSN 0031-4005, Vol. 132, no 2, E443-E451 p.Article in journal (Refereed) Published
    Abstract [en]

    OBJECTIVE: To investigate temporal, seasonal, and geographic variations in the incidence of necrotizing enterocolitis (NEC) and its relation to early infant survival in the Swedish population and in subgroups based on gestational age, birth weight, and gender. less thanbrgreater than less thanbrgreater thanMETHODS: In the Swedish birth cohort of 1987 through 2009 all children with a diagnosis of NEC were identified in the National Patient Register, the Swedish Medical Birth Register, and the National Cause of Death Register. NEC incidence, early mortality, and seasonality were analyzed with descriptive statistics, Poisson regression, and auto regression. less thanbrgreater than less thanbrgreater thanRESULTS: The overall incidence of NEC was 3.4 in 10 000 live births, higher in boys than in girls (incidence rate ratio 1.22, 95% confidence interval 1.06-1.40, P = .005), with a peak in November and a trough in May, and increased with an average of similar to 5% a year during the study period. In most subgroups, except the most immature, an initial decrease was followed by a steady increase. Seven-day mortality decreased strongly in all subgroups over the entire study period (annual incidence rate ratio 0.96, 95% confidence interval 0.95-0.96, P andlt; .001). This was especially marked in the most premature and low birth weight infants. less thanbrgreater than less thanbrgreater thanCONCLUSIONS: After an initial decrease, the incidence of NEC has increased in Sweden during the last decades. An association with the concurrent dramatically improved early survival seems likely.

    Place, publisher, year, edition, pages
    American Academy of Pediatrics, 2013
    Keyword
    necrotizing enterocolitis, premature infants, perinatal mortality, perinatal care, epidemiology, trends, seasonal variation
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-98148 (URN)10.1542/peds.2012-3847 (DOI)000322957300017 ()
    Note

    Funding Agencies|County Council of Ostergotland||Futurum||Academy of Health Care||Jonkoping County Council, Jonkoping, Sweden||Medical Research Council of Southeast Sweden||

    Available from: 2013-09-30 Created: 2013-09-30 Last updated: 2017-10-30
    2. Population-based study showed that necrotising enterocolitis occurred in space-time clusters with a decreasing secular trend in Sweden
    Open this publication in new window or tab >>Population-based study showed that necrotising enterocolitis occurred in space-time clusters with a decreasing secular trend in Sweden
    Show others...
    2017 (English)In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 106, no 7, 1097-1102 p.Article in journal (Refereed) Published
    Abstract [en]

    Aim: This study investigated space-time clustering of neonatal necrotising enterocolitis over three decades. Methods: Space-time clustering analyses objects that are grouped by a specific place and time. The Knox test and Kulldorffs scan statistic were used to analyse space-time clusters in 808 children diagnosed with necrotising enterocolitis in a national cohort of 2 389 681 children born between 1987 and 2009 in Sweden. The municipality the mother lived in and the delivery hospital defined closeness in space and the time between when the cases were born - seven, 14 and 21 days - defined closeness in time. Results: The Knox test showed no indication of space-time clustering at the residential level, but clear indications at the hospital level in all the time windows: seven days (p = 0.026), 14 days (p = 0.010) and 21 days (p = 0.004). Significant clustering at the hospital level was found during 1987-1997, but not during 1998-2009. Kulldorffs scan statistic found seven significant clusters at the hospital level. Conclusion: Space-time clustering was found at the hospital but not residential level, suggesting a contagious environmental effect after delivery, but not in the prenatal period. The decrease in clustering over time may reflect improved routines to minimise the risk of contagion between patients receiving neonatal care.

    Place, publisher, year, edition, pages
    WILEY, 2017
    Keyword
    Cluster analysis; Necrotising enterocolitis; Neonatal care; Precipitating contagion; Preterm infant
    National Category
    Pediatrics
    Identifiers
    urn:nbn:se:liu:diva-139608 (URN)10.1111/apa.13851 (DOI)000405216700022 ()28349558 (PubMedID)
    Note

    Funding Agencies|Swedish government; county councils

    Available from: 2017-08-16 Created: 2017-08-16 Last updated: 2017-10-30
  • Public defence: 2017-11-24 13:15 TEMCAS, Temahuset, Linköping
    Guo, Ming
    Linköping University, Department of Culture and Communication. Linköping University, Faculty of Arts and Sciences.
    Making a Market out of a Welfare State: Swedish Local Politicians’ Perspectives on Elderly Care Marketisation2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Market reforms have quite notably been used as a solution to increase the quality of public services and efficiency since the 1990s. Sweden has also introduced marketisation in the field of elderly care since 1992 to cope with increasing care needs while maintaining costs at a reasonable level. Yet, the introduction of a market mechanism in the welfare state is subject to increasing political and public debates. Many are sceptical about the purported benefits of a market, such as increased quality and reduced costs, as proposed by New Public Management. There have also been increasing critiques of the profit-making in care services in recent years.

    After two decades of marketisation, it is worthwhile to map out local politicians’ attitude patterns, namely, how they perceive the use of a market or quasi-market in a welfare state, where the market mechanism might challenge traditional principles such as universalism, solidarity, and equality. Complementary to studies on attitudes of public welfare, this research uses a unique survey dataset from 2014 to expand current understandings of politicians’ perspectives of marketisation.

    To be more specific, this study analyses three different aspects of marketisation: production, regulation, and financing. The results show that attitudinal differences between left- and right-wing politicians on private for-profit providers remain distinct. Political orientations of individuals, political majority in municipalities, and the privatisation level already achieved locally are identified as important factors in explaining local politicians’ willingness to privatise further. The preference differences continue to exist between the two blocs, and political ideology plays a major role in explaining these differences, more so than individual factors such as age, gender, or working position. Self-reported answers reveal that political ideology influences attitude formation.

    To a large extent, left- and right-wing politicians agree on welfare principles such as universalism, and they both recognise potential impacts that the market could have on society, such as inequality. It seems plausible that welfare state pluralism is the direction of the future.

    This case study serves as a solid example for examining the market development of public welfare in advanced welfare states and also contributes to the discussion of the potential role of political ideology in post-austerity welfare reforms.  

  • Public defence: 2017-11-30 10:15 ACAS, Hus A, Linköping
    Hochwallner, Martin
    Linköping University, Department of Management and Engineering, Manufacturing Engineering. Linköping University, Faculty of Science & Engineering.
    On Motion Control of Linear Incremental Hydraulic Actuators2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Linear Incremental Hydraulic Actuators combine one or more short-stroke cylinders, and two or more engaging/disengaging mechanisms into one actuator with long, medium, or even unlimited stroke length. The motion of each single short-stroke actuator concatenated by the engaging/disengaging mechanisms forms the motion of the linear incremental hydraulic actuator.

    The patterns of how these motions are concatenated form the gaits of a specific linear incremental hydraulic actuator. Linear incremental hydraulic actuators may have more than one gait. In an application, the gaits may be combined to achieve optimal performance at various operating points.

    The distinguishing characteristic of linear incremental hydraulic actuators is the incremental motion. The term incremental actuator is seen as analogous to the incremental versus absolute position sensor. Incremental actuators realize naturally relative positioning. Incremental motion means also that the behavior does not depend on an absolute position but only on the relative position within a cycle or step.

    Incremental actuators may realize discrete incremental or continuous incremental motion. Discrete incremental actuators can only approach discrete positions, whereby stepper drives are one prominent example. In contrast, continuous incremental actuators may approach any position. Linear electric motors are one example of continuous incremental actuators. The actuator has no inherent limitation in stroke length, as every step or cycle adds only to the state at the beginning of the step or cycle and does not depend on the absolute position. This led to the alternative working title Hydraulic Infinite Linear Actuator.

    Linear incremental hydraulic actuator provides long stroke, high force, and linear motion and has the potential to

    • decrease the necessary resource usage,
    • minimize environmental impact, e.g. from potential oil spillage,
    • extend the range of feasible products: longer, stiffer, better, etc.

    This thesis presents an analysis of the characteristics and properties of linear incremental hydraulic actuators as well as the gaits and possible realizations of some gaits. The gait for continuous, smooth motion with two cylinders is comprehensively studied and a control concept for the tracking problem is proposed. The control concept encapsulates the complexity of the linear incremental hydraulic actuator so that an application does not have to deal with it. One other gait, the ballistic gait, which realizes fast, energy-efficient motion, enabling energy recuperation is studied.

  • Public defence: 2017-11-30 13:15 Hugo Theorell, Linköping
    Lundengård, Karin
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    Mechanistic modelling - a BOLD response to the fMRI information loss problem2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Functional Magnetic Resonance Imaging (fMRI) is a common technique for imaging brain activity in humans. However, the fMRI signal stems from local changes in oxygen level rather than from neuronal excitation. The change in oxygen level is referred to as the Blood Oxygen Level Dependent (BOLD) response, and is connected to neuronal excitation and the BOLD response are connected by the neurovascular coupling. The neurons affect the oxygen metabolism, blood volume and blood flow, and this in turn controls the shape of the BOLD response. This interplay is complex, and therefore fMRI analysis often relies on models. However, none of the previously existing models are based on the intracellular mechanisms of the neurovascular coupling. Systems biology is a relatively new field where mechanistic models are used to integrate data from many different parts of a system in order to holistically analyze and predict system properties. This thesis presents a new framework for analysis of fMRI data, based on mechanistic modelling of the neurovascular coupling, using systems biology methods.

     Paper I presents the development of the first intracellular signaling model of the neurovascular coupling. Using models, a feed-forward and a feedback hypothesis are tested against each other. The resulting model can mechanistically explain both the initial dip, the main response and the post-peak undershoot of the BOLD response. It is also fitted to estimation data from the visual cortex and validated against variations in frequency and intensity of the stimulus. In Paper II, I present a framework for separating activity from noise by investigating the influence of the astrocytes on the blood vessels via release of vasoactive sub- stances, using observability analysis. This new method can recognize activity in both measured and simulated data, and separate differences in stimulus strength in simulated data. Paper III investigates the effects of the positive allosteric GABA modulator diazepam on working memory in healthy adults. Both positive and negative BOLD was measured during a working memory task, and activation in the cingulate cortex was negatively correlated to the plasma concentration of diazepam. In this area, the BOLD response had decreased below baseline in test subjects with >0.01 mg/L diazepam in the blood. Paper IV expands the model presented in Paper I with a GABA mechanism so that it can describe neuronal inhibition and the negative BOLD response. Sensitization of the GABA receptors by diazepam was added, which enabled the model to explain how changes to the BOLD response described in Paper III could occur without a change in the balance between the GABA and glutamate concentrations.

    The framework presented herein may serve as the basis for a new method for identification of both brain activity and useful potential biomarkers for brain diseases and disorders, which will bring us a deeper understanding of the functioning of the human brain.

    List of papers
    1. Mechanistic Mathematical Modeling Tests Hypotheses of the Neurovascular Coupling in fMRI
    Open this publication in new window or tab >>Mechanistic Mathematical Modeling Tests Hypotheses of the Neurovascular Coupling in fMRI
    Show others...
    2016 (English)In: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 12, no 6, e1004971Article in journal (Refereed) Published
    Abstract [en]

    Functional magnetic resonance imaging (fMRI) measures brain activity by detecting the blood-oxygen-level dependent (BOLD) response to neural activity. The BOLD response depends on the neurovascular coupling, which connects cerebral blood flow, cerebral blood volume, and deoxyhemoglobin level to neuronal activity. The exact mechanisms behind this neurovascular coupling are not yet fully investigated. There are at least three different ways in which these mechanisms are being discussed. Firstly, mathematical models involving the so-called Balloon model describes the relation between oxygen metabolism, cerebral blood volume, and cerebral blood flow. However, the Balloon model does not describe cellular and biochemical mechanisms. Secondly, the metabolic feedback hypothesis, which is based on experimental findings on metabolism associated with brain activation, and thirdly, the neurotransmitter feed-forward hypothesis which describes intracellular pathways leading to vasoactive substance release. Both the metabolic feedback and the neurotransmitter feed-forward hypotheses have been extensively studied, but only experimentally. These two hypotheses have never been implemented as mathematical models. Here we investigate these two hypotheses by mechanistic mathematical modeling using a systems biology approach; these methods have been used in biological research for many years but never been applied to the BOLD response in fMRI. In the current work, model structures describing the metabolic feedback and the neurotransmitter feed-forward hypotheses were applied to measured BOLD responses in the visual cortex of 12 healthy volunteers. Evaluating each hypothesis separately shows that neither hypothesis alone can describe the data in a biologically plausible way. However, by adding metabolism to the neurotransmitter feed-forward model structure, we obtained a new model structure which is able to fit the estimation data and successfully predict new, independent validation data. These results open the door to a new type of fMRI analysis that more accurately reflects the true neuronal activity.

    Place, publisher, year, edition, pages
    PUBLIC LIBRARY SCIENCE, 2016
    National Category
    Bioinformatics (Computational Biology)
    Identifiers
    urn:nbn:se:liu:diva-130437 (URN)10.1371/journal.pcbi.1004971 (DOI)000379349700045 ()27310017 (PubMedID)
    Note

    Funding Agencies|Swedish Research council [2014-6249]; Knut and Alice Wallenbergs foundation, KAW [2013.0076]; Research council of Southeast Sweden [FORSS-481691]; Linkoping University

    Available from: 2016-08-06 Created: 2016-08-05 Last updated: 2017-11-08
    2. Positive Allosteric Modulator of GABA Lowers BOLD Responses in the Cingulate Cortex
    Open this publication in new window or tab >>Positive Allosteric Modulator of GABA Lowers BOLD Responses in the Cingulate Cortex
    Show others...
    2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 3Article in journal (Refereed) Published
    Abstract [en]

    Knowledge about the neural underpinnings of the negative blood oxygen level dependent (BOLD) responses in functional magnetic resonance imaging (fMRI) is still limited. We hypothesized that pharmacological GABAergic modulation attenuates BOLD responses, and that blood concentrations of a positive allosteric modulator of GABA correlate inversely with BOLD responses in the cingulate cortex. We investigated whether or not pure task-related negative BOLD responses were co-localized with pharmacologically modulated BOLD responses. Twenty healthy adults received either 5 mg diazepam or placebo in a double blind, randomized design. During fMRI the subjects performed a working memory task. Results showed that BOLD responses in the cingulate cortex were inversely correlated with diazepam blood concentrations; that is, the higher the blood diazepam concentration, the lower the BOLD response. This inverse correlation was most pronounced in the pregenual anterior cingulate cortex and the anterior mid-cingulate cortex. For subjects with diazepam plasma concentration > 0.1 mg/L we observed negative BOLD responses with respect to fixation baseline. There was minor overlap between cingulate regions with task-related negative BOLD responses and regions where the BOLD responses were inversely correlated with diazepam concentration. We interpret that the inverse correlation between the BOLD response and diazepam was caused by GABA-related neural inhibition. Thus, this study supports the hypothesis that GABA attenuates BOLD responses in fMRI. The minimal overlap between task-related negative BOLD responses and responses attenuated by diazepam suggests that these responses might be caused by different mechanisms.

    Place, publisher, year, edition, pages
    San Francisco, CA, United States: Public Library of Science, 2016
    Keyword
    quantitative magnetic resonance imaging; brain tissue modeling; myelin; edema; T-1 relaxation; T-2 relaxation; proton density
    National Category
    Neurosciences
    Identifiers
    urn:nbn:se:liu:diva-126192 (URN)10.1371/journal.pone.0148737 (DOI)000371434500011 ()26930498 (PubMedID)
    Note

    Funding agencies: Linkoping University; County Council of Ostergotland

    Available from: 2016-03-18 Created: 2016-03-18 Last updated: 2017-11-08Bibliographically approved
    3. Neural inhibition can explain negative BOLD responses: A mechanistic modelling and fMRI study
    Open this publication in new window or tab >>Neural inhibition can explain negative BOLD responses: A mechanistic modelling and fMRI study
    Show others...
    2017 (English)In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 158, 219-231 p.Article in journal (Refereed) Published
    Abstract [en]

    Functional magnetic resonance imaging (fMRI) of hemodynamic changes captured in the blood oxygen level-dependent (BOLD) response contains information of brain activity. The BOLD response is the result of a complex neurovascular coupling and comes in at least two fundamentally different forms: a positive and a negative deflection. Because of the complexity of the signaling, mathematical modelling can provide vital help in the data analysis. For the positive BOLD response, there are plenty of mathematical models, both physiological and phenomenological. However, for the negative BOLD response, no physiologically based model exists. Here, we expand our previously developed physiological model with the most prominent mechanistic hypothesis for the negative BOLD response: the neural inhibition hypothesis. The model was trained and tested on experimental data containing both negative and positive BOLD responses from two studies: 1) a visual-motor task and 2) a workin-gmemory task in conjunction with administration of the tranquilizer diazepam. Our model was able to predict independent validation data not used for training and provides a mechanistic underpinning for previously observed effects of diazepam. The new model moves our understanding of the negative BOLD response from qualitative reasoning to a quantitative systems-biology level, which can be useful both in basic research and in clinical use.

    Place, publisher, year, edition, pages
    Elsevier, 2017
    Keyword
    fMRI; Neurovascular coupling; GABA; glutamate; Cerebral blood flow; Blood oxygen level dependent response; Hemodynamic response; Systems biology
    National Category
    Bioinformatics (Computational Biology)
    Identifiers
    urn:nbn:se:liu:diva-141844 (URN)10.1016/j.neuroimage.2017.07.002 (DOI)000411450600021 ()28687518 (PubMedID)2-s2.0-85022231713 (Scopus ID)
    Note

    Funding Agencies|Swedish Research Council [20146249]; Knut and Alice Wallenbergs foundation, KAW [2013.0076]; Research council of Southeast Sweden [FORSS-481691]; Linkoping University local funds

    Available from: 2017-10-09 Created: 2017-10-09 Last updated: 2017-11-08Bibliographically approved
  • Public defence: 2017-12-01 10:15 K3, Kåkenhus, Norrköping
    Tshabalala, Xolani
    Linköping University, Department of Social and Welfare Studies, REMESO - Institute for Research on Migration, Ethnicity and Society. Linköping University, Faculty of Arts and Sciences.
    Hyenas of the Limpopo: The Social Politics of Undocumented Movement Across South Africa’s Border with Zimbabwe2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    An increasing number of people today cross the Beitbridge border of South Africa and Zimbabwe. This comes with a corresponding growth of creative strategies that seek to aid the crossing of those people and goods that may lack the necessary documentation. Such ‘informal’ border crossings have come to define one of the important economic regions in Southern Africa, the post-1994 Limpopo Valley.

    This thesis approaches routine acts of facilitating undocumented border crossings as an everyday social politics with deep historical roots. By use of archival and ethnographic methods, the thesis examines the social history and embodied practices of a variety of actors who engage in undocumented border crossings. A particular focus is placed on the role of private transporters (omalayitsha), who represent an important link between an exclusionary and yet fragmentary migration regime and undocumented travellers. In three theoretical and four empirical chapters, and inspired by border studies as well as the critical realist approach in migration studies, the thesis connects border practice to irregular movement and cheap labour within a regional context defined, in part, by dispossession. Through thick interpretations of the lived experience of border practice, the study also connects such political economic processes (e.g. migrant irregularity, labour precarity and economic informality) to questions of social identity and migrant subjectivities.

    By situating the figure of the hyena at the centre of Southern African border struggles, the thesis invents an analytical concept that serves both an empirical and a theoretical task. Empirically, it enables a synthetic understanding of how everyday contestations around the possibility to work across the border for low-skill migrants have been interacting, through time, with broader processes of capital accumulation to partly shape the region’s migrant labour system. Theoretically, it shows how facilitation of undocumented border crossings calls for new sociological models that can account for processes that escape binary classification (as formal or informal, inclusive or exclusive, legal or illegal, ordered or disordered), thus contributing to a better understanding of the role of migration in the contemporary world. 

  • Public defence: 2017-12-01 13:00 Runstenen, Norrköping
    Bäckström, Denise
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Norrköping.
    Injury mortality in Sweden; changes over time and the effect of age and injury mechanism2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Injuries are one of the most common causes of death in the world. Varying types of injuries dominate in different parts of the world, which also have separate influences mortality. In Scandinavia blunt injuries dominates and the majority of those who die do so pre hospital. Over time different injury pattern may vary and by analyzing this we can assess when, where and how preventive work can be reinforced. The aim of this thesis was to study injury epidemiology in Sweden and assess the contribution of different injury patters on mortality.

    Method: We used the Swedish cause of death and the national patient registries which have a complete national coverage. ICISS was calculated (based on ICD-10) in the in hospital population. We have chosen to do this investigation with a broad perspective using the term injury, which includes trauma but also other diagnoses like suffocation and drowning.

    Results: During the study period (1999-2012) the number of deaths because of injury was 1213, 25 388, and 18 332 among children, working age and elderly, respectively. Mortality declined in the children and in the working age but inclined in the elderly. Mortality increased with each age group except between the ages of 15–25 and 26–35 years. One thousand two hundred sixty four (97%) of those who died because of penetrating trauma (sharp objects and firearms) were killed by intentional trauma (assault and intentional self-harm). One thousand and seventeen (83%) of the children died prehospital. In the working age 22 211 (80%) of 25 388 died pre hospital. Nine thousand six hundred and eighteen (53%) of 18 332 of the elderly died prehospital. During 2001- 2011 the risk adjusted in hospital mortality decreased in traffic and assault but not in fall related injuries.

    Discussion: Largely, the anticipated injury mortality picture was found, with blunt injuries (traffic accidents) dominating in the working age and falls in elderly. Further a significant portion of the deaths occurred pre hospital. The intentional injuries are dominated by intentional selfharm. The decrease in child injury mortality is notable as Sweden already has one of the lowest incidences in child injury mortality in the world. The decrease in injury mortality in the working age also implies that preventive work has had an effect. The incline in injury mortality in elderly on the other hand needs to be further studied. Areas of particular importance for future preventive work is the incline in injury mortality in elderly and intentional injuries among children. 

    List of papers
    1. Change in child mortality patterns after injuries in Sweden: a nationwide 14-year study.
    Open this publication in new window or tab >>Change in child mortality patterns after injuries in Sweden: a nationwide 14-year study.
    2017 (English)In: European Journal of Trauma and Emergency Surgery, ISSN 1863-9933, E-ISSN 1863-9941, Vol. 43, no 3, 343-349 p.Article in journal (Refereed) Published
    Abstract [en]

    INTRODUCTION: Sweden has one of the world's lowest child injury mortality rates, but injuries are still the leading cause of death among children. Child injury mortality in the country has been declining, but this decline seems to decrease recently. Our objective was therefore to further examine changes in the mortality of children's death from injury over time and to assess the contribution of various effects on mortality. The underlying hypothesis for this investigation is that the incidence of lethal injuries in children, still is decreasing and that this may be sex specific.

    PATIENTS AND METHODS: We studied all deaths from injury in Sweden under-18-year-olds during the 14 years 1999-2012. We identified those aged under 18 whose underlying cause of death was recorded as International Classification of Diseases, 10th Revision (ICD-10) diagnosis from V01 to X39 in the Swedish cause of death, where all dead citizens are registered.

    RESULTS: From the 1 January 1999 to 31 December 2012, 1213 children under the age of 18 died of injuries in Sweden. The incidence declined during this period (r = -0.606, p = 0.02) to 3.3 deaths/100,000 children-years (95 % CI 2.6-4.2). Death from unintentional injury was more common than that after intentional injury (p < 0.0001). There was a reduction in the incidence of unintentional injuries during the study period (r = -0.757, p = 0.03). The most common causes of death were injury to the brain (n = 337, 41 %), followed by drowning (n = 109, 13 %). The number of deaths after intentional injury increased (r = 0.585, p = 0.03) and at the end of the period was 1.5 deaths/100,000 children-years. The most common causes of death after intentional injuries were asphyxia (n = 177, 45 %), followed by injury to the brain (n = 76, 19 %).

    DISCUSSION: Mortality patterns in injured children in Sweden have changed from being dominated by unintentional injuries to a more equal distribution between unintentional and intentional injuries as well as between sexes and the overall rate has declined further. These findings are important as they might contribute to the preventive work that is being done to further reduce mortality in injured children.

    Place, publisher, year, edition, pages
    Springer, 2017
    Keyword
    Children, Injury, Mortality, Scandinavia, Trauma
    National Category
    Other Clinical Medicine
    Identifiers
    urn:nbn:se:liu:diva-135548 (URN)10.1007/s00068-016-0660-y (DOI)000402789500010 ()27084542 (PubMedID)
    Note

    Funding agencies: Swedish Carnegie Hero Fund

    Available from: 2017-03-16 Created: 2017-03-16 Last updated: 2017-11-02Bibliographically approved
    2. Deaths caused by injury among people of working age (18-64) are decreasing, while those among older people (64+) are increasing.
    Open this publication in new window or tab >>Deaths caused by injury among people of working age (18-64) are decreasing, while those among older people (64+) are increasing.
    Show others...
    2017 (English)In: European Journal of Trauma and Emergency Surgery, ISSN 1863-9933, E-ISSN 1863-9941Article in journal (Refereed) Epub ahead of print
    Abstract [en]

    BACKGROUND: Injury is an important cause of death in all age groups worldwide, and contributes to many losses of human and economic resources. Currently, we know a few data about mortality from injury, particularly among the working population. The aim of the present study was to examine death from injury over a period of 14 years (1999-2012) using the Swedish Cause of Death Registry (CDR) and the National Patient Registry, which have complete national coverage.

    METHOD: CDR was used to identify injury-related deaths among adults (18 years or over) during the years 1999-2012. ICD-10 diagnoses from V01 to X39 were included. The significance of changes over time was analyzed by linear regression.

    RESULTS: The incidence of prehospital death decreased significantly (coefficient -0.22, r (2) = 0.30; p = 0.041) during the study period, while that of deaths in hospital increased significantly (coefficient 0.20, r (2) = 0.75; p < 0.001). Mortality/100,000 person-years in the working age group (18-64 years) decreased significantly (coefficient -0.40, r (2) = 0.37; p = 0.020), mainly as a result of decrease in traffic-related deaths (coefficient -0.34, r (2) = 0.85; p < 0.001). The incidence of deaths from injury among elderly (65 years and older) patients increased because of the increase in falls (coefficient 1.71, r (2) = 0.84; p < 0.001) and poisoning (coefficient 0.13, r (2) = 0.69; p < 0.001).

    CONCLUSION: The epidemiology of injury in Sweden has changed during recent years in that mortality from injury has declined in the working age group and increased among those people 64 years old and over.

    Place, publisher, year, edition, pages
    Springer, 2017
    Keyword
    Elderly, Injury, Mortality, Prehospital, Trauma, Working age
    National Category
    Public Health, Global Health, Social Medicine and Epidemiology
    Identifiers
    urn:nbn:se:liu:diva-142763 (URN)10.1007/s00068-017-0827-1 (DOI)28825159 (PubMedID)
    Available from: 2017-11-02 Created: 2017-11-02 Last updated: 2017-11-02Bibliographically approved
  • Public defence: 2017-12-01 13:00 Berzeliussalen, Linköping
    Bengtsson, Håkan
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Medicine and Health Sciences.
    Match-related risk factors for injury in male professional football2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Injuries are common in professional football, especially during matches, and they cause suffering for players, in both the short and the long term. It is therefore important to try to prevent these injuries. One of the most important steps in injury prevention is to fully understand the different risk factors that contribute to these injuries.

    Aim: The aim of this thesis was therefore to investigate several match-related factors that have been suggested to be important for the risk of sustaining injuries during professional football matches.

    Methods: The thesis consists of four papers, and all analyses are based on data gathered during a large-scale prospective cohort study that has been running since 2001: the UEFA Elite Club Injury Study. Medical teams from 61 clubs have been involved in this study, and they have prospectively gathered data about football exposure and injuries for their first team players.

    Associations between the following factors and injuries have been analysed: • Match characteristics in terms of match venue, match result, and competition • Match congestion, both short and long term, and at team and individual player level • Number of completed training sessions between return to sport after an injury and the first match exposure

    Results: All match characteristics studied were shown to be associated with injury rates, with higher injury rates during home matches compared with away matches, in matches that were lost or drawn compared with matches won, and in domestic league and Champions League matches compared with Europa League and other cup matches. It was also shown that injury rates, muscle injury rates in particular, were higher if the recovery time between matches was short. This association between match congestion and injury rates was shown when match congestion was considered at both team and individual player level. Finally, the odds of injury during the first match exposure after a period of absence due to injury was found to be higher if players had completed few training sessions between return to sport and their first match.

    Conclusion: There are several match-related risk factors that contribute to the injury rate during professional football matches. A better understanding of these risk factors will help teams to make better estimations of the injury risks to which players are exposed in different situations (e.g. during periods of match congestion and when players return to sport after an injury). Knowledge about risk factors will also offer the possibility of reducing the number of injuries for football teams by addressing them with appropriate measures.

    List of papers
    1. Match Injury Rates in Professional Soccer Vary With Match Result, Match Venue, and Type of Competition
    Open this publication in new window or tab >>Match Injury Rates in Professional Soccer Vary With Match Result, Match Venue, and Type of Competition
    2013 (English)In: American Journal of Sports Medicine, ISSN 0363-5465, E-ISSN 1552-3365, Vol. 41, no 7, 1505-1510 p.Article in journal (Refereed) Published
    Abstract [en]

    Background: Player activities in soccer matches are influenced by the match result and match venue. It is not known whether injury rates are influenced by these factors. Purpose: To investigate whether there are associations between injury rates and the match result, venue, and type of competition in male soccer. Study Design: Cohort study; Level of evidence, 3. Methods: Twenty-six professional clubs from 10 countries were followed prospectively during 9 seasons (2001-2002 to 2009-2010). All matches, and injuries occurring in these matches, were registered by the teams medical staff. An injury was registered if it resulted in player absence from training or matches. Information about match result, venue, and type of competition for all reported matches was gathered by the authors from online databases. Injury rates in matches with varying match characteristics were compared by use of generalized estimating equations. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Results: A total of 2738 injuries during 6010 matches were registered. There were no associations between odds of 1 injury occurrence and match result or type of competition, whereas the odds were decreased in matches played away compared with home matches (OR, 0.89; 95% CI, 0.80-0.99). The odds of 2 or more injury occurrences in a match were increased in matches resulting in a draw (OR, 1.39; 95% CI, 1.15-1.69) or loss (OR, 1.66; 95% CI, 1.38-1.98) compared with matches won and were decreased in other cup matches compared with league matches (OR, 0.57; 95% CI, 0.39-0.84) and in matches played away compared with home matches (OR, 0.70; 95% CI, 0.60-0.82). Finally, injuries with more than 1 weeks absence occurred more frequently in Champions League matches compared with league matches both for matches with 1 injury (OR, 1.26; 95% CI, 1.09-1.45) and matches with 2 or more injuries (OR, 1.57; 95% CI, 1.13-2.20). Conclusion: The odds of 2 or more injury occurrences in professional soccer were higher in matches resulting in a loss or a draw compared with a win, whereas the odds of injury occurrences were lower in matches played away compared with home matches. The rate of moderate and severe injuries increased with the importance of the match.

    Place, publisher, year, edition, pages
    SAGE Publications (UK and US): No SAGE Choice, 2013
    Keyword
    athletic injuries; competition; football; performance; risk factors
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-105047 (URN)10.1177/0363546513486769 (DOI)000330524000011 ()
    Available from: 2014-03-06 Created: 2014-03-06 Last updated: 2017-11-03
    2. Muscle injury rates in professional football increase with fixture congestion: an 11-year follow-up of the UEFA Champions League injury study
    Open this publication in new window or tab >>Muscle injury rates in professional football increase with fixture congestion: an 11-year follow-up of the UEFA Champions League injury study
    2013 (English)In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 47, no 12, 743-747 p.Article in journal (Refereed) Published
    Abstract [en]

    Background The influence of fixture congestion on injury rates and team performance has only been scarcely investigated.

    Aim To study associations between recovery time and match load and injury rates and team performance in professional football.

    Methods Exposure and time loss injuries were registered prospectively from 27 teams over 11 seasons. Matches were grouped according to recovery days before each match (≤3 vs >3 days, and ≤4 vs ≥6 days). Injury rates and team performance were compared between groups. Match load in match sequences containing five consecutive matches was determined by the number of days separating the first match and the last training session during that match sequence. Linear regression was used to study associations between match load and injury rates and team performance.

    Results Team performance showed no association with match load, or recovery days prior to matches, except for Europa League matches that indicated more matches lost with short recovery (≤3 days) (p=0.048). Total injury rates and muscle injury rates were increased in league matches with ≤4 days compared with ≥6 days’ recovery (RR 1.09, 95% CI 1.00 to 1.18, and RR 1.32, 95% CI 1.15 to 1.51, respectively), specifically hamstring and quadriceps injuries. High match load was associated with increase in muscle injury rate in matches in the same match sequence (p=0.012), and increase in ligament injury rate in training in the subsequent match sequence (p=0.003).

    Conclusions Fixture congestion was associated with increased muscle injury rates but had no, or very limited, influence on team performance.

    Place, publisher, year, edition, pages
    BMJ Publishing Group, 2013
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-97448 (URN)10.1136/bjsports-2013-092383 (DOI)000322868800008 ()23851296 (PubMedID)
    Note

    Funding Agencies|Union of European Football Associations (UEFA)||Swedish National Centre for Research in Sports, and Praktikertjanst AB||

    Available from: 2013-09-12 Created: 2013-09-12 Last updated: 2017-11-03Bibliographically approved
  • Public defence: 2017-12-01 13:34 VAL, Vallfarten, Linköping
    Wallsten, Anna
    Linköping University, Department of Thematic Studies, Technology and Social Change. Linköping University, Faculty of Arts and Sciences.
    Assembling the Smart Grid: On the Mobilization of Imaginaries, Users and Materialities in a Swedish Demonstration Project2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Influential actors refer to smart grids as a revamped version of the energy systemwhen they argue for alternative energy pathways, and assign demonstration projects with the task of turning prospects about the future into functional configurations. This thesis explores notions of the smart grid future that are implicitly conveyed in Swedish smart grid strategy and planning documents. The purpose of this thesis is to describe and analyse how a smart grid is assembled in a Swedish demonstration project. Inspired by Science and Technology Studies (STS), it explores this process through interviews, document studies and participant observation. By combining concepts such as sociotechnical imaginaries, material participation and translations, this study sheds light on the negotiations, tensions and struggles at play in the process of making smart grids functional. This study examines how included and excluded users make sense of the smart grid and of their own role in shaping the future. What imaginaries do the actors involved in the project draw on? What materialities take part in shaping the smart grid, and what user engagements are encouraged? The aim of the study is to seek an enhanced understanding of how smart grids are made, of the different forces that shape this process and, ultimately, of the reality of Swedish households as part of a smart grid in the making. This study shows that making a smart grid functional is not as feasible as the smart grid imaginaries suggest, and it finds potential in user engagements that are suppressed within the current market regime, which is primarily arranged around economic incentives.

  • Public defence: 2017-12-07 09:00 Berzeliussalen, Linköping
    Kihlberg, Johan
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Magnetic Resonance Imaging of Myocardial Deformation and Scarring in Coronary Artery Disease.2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Although improved treatments have reduced the rates of acute complications from myocardial infarction, sequelae such as heart failure and sudden death threaten the future wellbeing of those patients. Secondary prevention after myocardial infarction is related to cardiovascular risk factors and the effect of the infarct on left ventricular function. Cardiovascular magnetic resonance imaging (CMR) is necessary to determine the size of the infarct scar and can with great precision determine left ventricular volumes, left ventricular ejection fraction, and deformation (strain and torsion). The purpose of this thesis was to improve on CMR methods to facilitate image acquisition and post processing in patients with high risk of coronary artery disease (CAD).

    In Paper 1, a three-dimensional phase-sensitive inversion-recovery (3D PSIR) sequence was modified to measure T1 during a single breath hold. The measured T1 values were used to extrapolate a map of T1 relaxation, which avoided the time-consuming manual determination of the inversion time. The data collection consisted of phantom experiments, Monte Carlo simulations of the effect of various heart rates, and clinical investigation of 18 patients with myocardial infarction. Scar images created with the modified sequence were compared to those created with the standard sequence. The 3D PSIR sequence was able to measure T1 relaxation with a high accuracy up to 800 ms, which is in the suitable range for scar imaging. Simulated arrhythmias showed that the method was robust and able to tolerate some variation in heart rate. The modified sequence provides measurements of inversion time that can be used to facilitate standard scar imaging or to reconstruct synthetic scar images. Images of infarct scar obtained with the 3D PSIR sequence bore striking similarity to images obtained with the standard sequence.

    In Paper 2, 125 patients with high risk of CAD were investigated using the displacement encoding with stimulated echoes (DENSE) sequence. Image segments with infarct scar area >50% (transmurality) could be identified with a sensitivity of 95% and a specificity of 80% based on circumferential strain calculated from the DENSE measurements. The DENSE sequence was also applied in other directions, but its sensitivity and specificity to detect scar was lower than when used for circumferential strain.

    In Paper 3, 90 patients with high risk of CAD were examined by DENSE, tagging with harmonic phase (HARP) imaging and cine imaging with feature tracking (FT), to detect cardiac abnormalities as manifested in end-systolic circumferential strain. Circumferential strain calculated with DENSE had higher sensitivity and specificity than the competing methods to detect infarction with transmurality >50%. Global circumferential strain measured by DENSE correlated better with global parameters such as left ventricular ejection fraction, myocardial wall mass, left ventricular end-diastolic and end-systolic volume; than strain measured by FT or HARP.

    In Paper 4, myocardial torsion was investigated using DENSE, HARP, and FT in 48 patients with high risk of CAD. Torsion measured by each of the three methods was correlated with other global measures such as left ventricular ejection fraction, left ventricular mass, and left ventricular end-diastolic and end-systolic volumes. The torsion measurements obtained with DENSE had a stronger relationship with left ventricular ejection fraction, left ventricular mass, and volumes than those obtained with HARP or FT.

    DENSE was superior to the other methods for strain and torsion measurement and can be used to describe myocardial deformation quantitatively and objectively.

    List of papers
    1. Rapid T1 quantification based on 3D phase sensitive inversion recovery
    Open this publication in new window or tab >>Rapid T1 quantification based on 3D phase sensitive inversion recovery
    2010 (English)In: BMC Medical Imaging, ISSN 1471-2342, Vol. 10, no 19Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND: In Contrast Enhanced Magnetic Resonance Imaging fibrotic myocardium can be distinguished from healthy tissue using the difference in the longitudinal T1 relaxation after administration of Gadolinium, the so-called Late Gd Enhancement. The purpose of this work was to measure the myocardial absolute T1 post-Gd from a single breath-hold 3D Phase Sensitivity Inversion Recovery sequence (PSIR). Equations were derived to take the acquisition and saturation effects on the magnetization into account.

    METHODS: The accuracy of the method was investigated on phantoms and using simulations. The method was applied to a group of patients with suspected myocardial infarction where the absolute difference in relaxation of healthy and fibrotic myocardium was measured at about 15 minutes post-contrast. The evolution of the absolute R1 relaxation rate (1/T1) over time after contrast injection was followed for one patient and compared to T1 mapping using Look-Locker. Based on the T1 maps synthetic LGE images were reconstructed and compared to the conventional LGE images.

    RESULTS: The fitting algorithm is robust against variation in acquisition flip angle, the inversion delay time and cardiac arrhythmia. The observed relaxation rate of the myocardium is 1.2 s-1, increasing to 6 - 7 s-1 after contrast injection and decreasing to 2 - 2.5 s-1 for healthy myocardium and to 3.5 - 4 s-1 for fibrotic myocardium. Synthesized images based on the T1 maps correspond very well to actual LGE images.

    CONCLUSIONS: The method provides a robust quantification of post-Gd T1 relaxation for a complete cardiac volume within a single breath-hold.

    National Category
    Engineering and Technology Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-59065 (URN)10.1186/1471-2342-10-19 (DOI)20716333 (PubMedID)
    Available from: 2010-09-08 Created: 2010-09-08 Last updated: 2017-11-15
    2. Clinical experience of strain imaging using DENSE for detecting infarcted cardiac segments
    Open this publication in new window or tab >>Clinical experience of strain imaging using DENSE for detecting infarcted cardiac segments
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    2015 (English)In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 17, 50Article in journal (Refereed) Published
    Abstract [en]

    Background

    We hypothesised that myocardial deformation determined with magnetic resonance imaging (MRI) will detect myocardial scar.

    Methods

    Displacement Encoding with Stimulated Echoes (DENSE) was used to calculate left ventricular strain in 125 patients (29 women and 96 men) with suspected coronary artery disease. The patients also underwent cine imaging and late gadolinium enhancement. 57 patients had a scar area >1 % in at least one segment, 23 were considered free from coronary artery disease (control group) and 45 had pathological findings but no scar (mixed group). Peak strain was calculated in eight combinations: radial and circumferential strain in transmural, subendocardial and epicardial layers derived from short axis acquisition, and transmural longitudinal and radial strain derived from long axis acquisitions. In addition, the difference between strain in affected segments and reference segments, “differential strain”, from the control group was analysed.

    Results

    In receiver-operator-characteristic analysis for the detection of 50 % transmurality, circumferential strain performed best with area-under-curve (AUC) of 0.94. Using a cut-off value of -17 %, sensitivity was 95 % at a specificity of 80 %. AUC did not further improve with differential strain. There were significant differences between the control group and global strain circumferential direction (-17 % versus -12 %) and in the longitudinal direction (-13 % versus -10 %). Interobserver and scan-rescan reproducibility was high with an intraclass correlation coefficient (ICC) >0.93.

    Conclusions

    DENSE-derived circumferential strain may be used for the detection of myocardial segments with >50 % scar area. The repeatability of strain is satisfactory. DENSE-derived global strain agrees with other global measures of left ventricular ejection fraction.

    Place, publisher, year, edition, pages
    BioMed Central, 2015
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:liu:diva-119846 (URN)10.1186/s12968-015-0155-8 (DOI)000356652000001 ()26104510 (PubMedID)
    Available from: 2015-06-26 Created: 2015-06-26 Last updated: 2017-11-15
  • Public defence: 2017-12-08 09:00 Berzeliussalen, Linköping
    Pihl Lesnovska, Katarina
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Gastroentorology.
    Life situation among persons living with inflammatory bowel disease.2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Living with inflammatory bowel disease (IBD) affects physical, psychological and social dimensions, limiting the ability to engage in daily activities. Persons with IBD may need frequent and lifelong contacts with the healthcare (HC), highlighting the importance of quality care. High quality HC for persons with IBD involves a partnership between the HC professionals and the person living with the disease. Information is essential, the more a person knows about their disease, the more concordant and satisfied with their treatment they are likely to be.

    The overall aim of this thesis was to describe the knowledge need, life situation and perception of HC among persons living with IBD, in order to develop a questionnaire to evaluate the quality of HC.

    This thesis is based on three studies that are presented in four papers. Qualitative methods were used to describe aspects of life situation in relation to the disease, whereas quantitative method was used to develop a questionnaire measuring quality of care. Study I and II have an inductive qualitative design. In study I, qualitative interviews with 30 people were performed to describe the knowledge need and experience of critical incidents in daily life while living with IBD. The interviews in study I were analyzed using content analysis (results presented in Paper I) and critical incident technique (results presented in Paper II). In study II, the perceptions of HC among persons living with IBD was explored in five focus group interviews and two individual interviews, in total n=26. Study III aimed to develop and evaluate a questionnaire, measuring quality of care among persons with IBD, including 318 persons with IBD and 8 professionals. The knowledge need among persons with IBD focused on managing symptoms and course of the disease and learning to assimilate the information in order to manage everyday life. Losing bowel control was of great concern for most of the informants in the study. Many of the informants said that “the bowel ruled their life” and that it influenced them to a great extent in their daily lives. The perception of HC among persons with IBD meant being met with respect and mutual trust, receiving information at the right time, shared decision-making, competence and communication, access to care, accommodation, continuity of care and the pros and cons of specialized care. The quality of care questionnaire QoC-IBD was constructed in five dimensions, building on the results from Study I and II. The dimensions were trust and respect, decision-making, information, continuity of care and access to care consisting of 21 questions in total. QoC-IBD is a short, self-administrated questionnaire that measures experiences of healthcare among persons with IBD with promising validity and reliability.

    To improve quality of care, HC is recommended to consider individual care needs and take the person’s daily life and social context into account. The QoC-IBD questionnaire measures the subjective experience of quality of care. Further testing in clinical practice is necessary to evaluate if QoC-IBD can be used to evaluate the care given and areas of improvement in HC for persons living with IBD.

    List of papers
    1. What do patients need to know? Living with inflammatory bowel disease
    Open this publication in new window or tab >>What do patients need to know? Living with inflammatory bowel disease
    2014 (English)In: Journal of Clinical Nursing, ISSN 0962-1067, E-ISSN 1365-2702, Vol. 23, no 11-12, 1718-1725 p.Article in journal (Refereed) Published
    Abstract [en]

    AIMS AND OBJECTIVES: To explore the need for knowledge as expressed by patients diagnosed with inflammatory bowel disease.

    BACKGROUND: Inflammatory bowel disease has a major impact on physical and emotional well-being, placing considerable demands on patients' management of daily activities. Although inflammatory bowel disease patients' level of knowledge about their disease has been previously studied, it is necessary to learn more about their self-expressed needs.

    DESIGN: The study was designed to explore patients' need for knowledge; therefore, an inductive method was chosen.

    METHODS: Thirty patients with inflammatory bowel disease were interviewed. Content analysis was used to describe their need for knowledge.

    RESULTS: The analysis generated three categories and eight subcategories: (1) knowledge related to the course of the disease (subcategories: understanding causal relationships between symptoms and the disease, complications related to the disease and understanding treatment), (2) knowledge related to managing everyday life (subcategories: behaviour that enhances well-being and managing social life) and (3) difficulty understanding and assimilating information (subcategories: shifting knowledge needs, help to understand information and reasons for wanting or not wanting knowledge).

    CONCLUSION: Knowledge needs were related to what to expect when living with inflammatory bowel disease in order to manage everyday life. There was a great variation in the need for knowledge, which was greatest immediately following diagnosis and during relapse.

    RELEVANCE TO CLINICAL PRACTICE: It is important for healthcare providers to ascertain the patients' individual knowledge needs and together with them formulate an individual care plan that gives the patient the necessary knowledge to manage their health and social life.

    Place, publisher, year, edition, pages
    Wiley-Blackwell, 2014
    Keyword
    content analysis, Crohn's disease, knowledge need and ulcerative colitis
    National Category
    Gastroenterology and Hepatology
    Identifiers
    urn:nbn:se:liu:diva-97578 (URN)10.1111/jocn.12321 (DOI)000335443800027 ()24004406 (PubMedID)
    Available from: 2013-09-17 Created: 2013-09-17 Last updated: 2017-11-01
    2. Critical situations in daily life as experienced by patients with inflammatory bowel disease
    Open this publication in new window or tab >>Critical situations in daily life as experienced by patients with inflammatory bowel disease
    2016 (English)In: Gastroenterology Nursing, ISSN 1042-895X, Vol. 39, no 3, 195-203 p.Article in journal (Refereed) Published
    Abstract [en]

    Crohn disease and ulcerative colitis, collectively known as inflammatory bowel disease (IBD), are chronic and have a fluctuating clinical course that impacts daily life. Daily life with a chronic disease involves thinking and worrying about the limitations that chronic disease causes. Knowledge about how patients who suffer from IBD manage critical incidents in daily life is lacking. The aim of the study was to describe how patients living with IBD experience critical incidents in daily life in relation to their disease and symptoms. Thirty adult patients were interviewed focusing on critical incidents in daily life. Data were analyzed using the critical incident technique. The study comprised 224 critical incidents and was grouped into 21 subcategories and 5 categories: losing bowel control, having a body that smells, being unable to meet own and others' expectations, not being believed or seen, and experiencing frustration due to side effects and ineffective treatment. These categories formed one main area describing the overall result "The bowels rule life." The uncertain nature of IBD created critical incidents in which the bowel ruled life, causing patients to avoid social interaction. It also placed considerable demands on the family and sometimes had a negative effect on the afflicted person's career.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.

    Place, publisher, year, edition, pages
    Lippincott Williams & Wilkins, 2016
    National Category
    Gastroenterology and Hepatology
    Identifiers
    urn:nbn:se:liu:diva-126621 (URN)10.1097/SGA.0000000000000211 (DOI)000380804500004 ()26870902 (PubMedID)
    Note

    Funding agencies: We acknowledge funding from the County Council of Ostergotland.

    Available from: 2016-03-31 Created: 2016-03-31 Last updated: 2017-11-01Bibliographically approved
    3. Healthcare as perceived by persons with inflammatory bowel disease – a focus group study
    Open this publication in new window or tab >>Healthcare as perceived by persons with inflammatory bowel disease – a focus group study
    Show others...
    2017 (English)In: Journal of Clinical Nursing, ISSN 0962-1067Article in journal (Refereed) Accepted
    Abstract [en]

    Background: The quality of care plays an important role in the life of persons with a chronic disease. In order to define what persons with inflammatory bowel disease perceive as high quality care, greater focus must be placed on the individual’s own perspective of living with the condition. Design: A qualitative exploratory study was conducted based on focus groups. Methods: Five focus groups were conducted with adult persons living with inflammatory bowel disease, fourteen men and twelve women aged 19-76 years. The interviews were performed between January and June 2014. Results: The perceptions of healthcare from the perspective of persons living with inflammatory bowel disease were summarized in two categories: “Professional attitudes of healthcare staff” and “Structure of the healthcare organization”. Persons with Inflammatory bowel disease want to be encountered with respect, experience trust and obtain information at the right time. They also expect shared decision-making, communication and to encounter competent healthcare professionals. Furthermore, the expectations on and perceptions of the structure of the healthcare organization comprises access to care, accommodation, continuity of care, as well as the pros and cons of specialized care. Conclusion: The findings show the importance of establishing a respectful and trusting relationship, facilitating healthcare staff and persons with inflammatory bowel disease to work as a team in fulfilling individual care needs – but there is room for improvement in terms of quality of care. Relevance to clinical practice: A person-centred approach, which place the individual and her/his family at the centre, considering them experts on their own health and enabling them to collaborate with healthcare staff, seems important to reach a high quality healthcare organization for patients with IBD.

    Place, publisher, year, edition, pages
    Wiley-Blackwell, 2017
    Keyword
    Focus group interview, inflammatory bowel disease, quality of care
    National Category
    Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-134416 (URN)10.1111/jocn.13740 (DOI)
    Available from: 2017-02-10 Created: 2017-02-10 Last updated: 2017-11-01
  • Public defence: 2017-12-08 10:15 Schrödinger, Fysikhuset, Linköping
    Wang, Chuanfei
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Electronic Structure of π-Conjugated Materials and Their Effect on Organic Photovoltaics2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The great tunability of structure and electronic properties of π-conjugated organic molecules/polymers combined with other advantages such as light weight and flexibility etc., have made organic-based electronics the focus of an exciting still-growing field of physics and chemistry for more than half a century. The application of organic electronics has led to the appearance of wide range of organic electronic devices mainly including organic light emitting diodes (OLED), organic field effect transistors (OFET) and organic solar cells (OSC). The application of the organic electronic devices mainly is limited by two dominant parameters, i.e., their performance and stability. Up to date, OLED has been successfully commercialized in the market while the OSC are still on the way to commercialization hindered by low efficiency and inferior stability. Understanding the energy levels of organic materials and energy level alignment of the devices is crucial to control the efficiency and stability of the OSC. In this thesis, energy levels measured by different methods are studied to explore their relationship with device properties, and the strategies on how to design efficient and stable OSC based on energy level diagrams are provided.

    Cyclic Voltammetry (CV) is a traditional and widely used method to probe the energy levels of organic materials, although there is little consensus on how to relate the oxidation/reduction potential ((Eox/Ered) to the vacuum level. Ultraviolet Photoelectron Spectroscopy (UPS) can be used to directly detect vertical ionization potential (IP) of organic materials. In this thesis, a linear relationship of IP and Eox was found, with a slope equal to unity. The relationship provides for easy conversion of values obtained by the two techniques, enabling complementarily use in designing and fabricating efficient and stable OSC. A popular rule of thumb is that the offset between the LUMO levels of donor and acceptor should be 0.3 eV, according to which a binary solar cell with the minimum voltage losses around 0.49 V was designed here.

    Introduction of the ternary blend as active layer is an efficient way to improve both efficiency and stability of the OSC. Based on our studied energy-level diagram within the integer charge transfer (ICT) model, we designed ternary solar cells with enhanced open circuit voltage for the first time and improved thermal stability compared to reference binary ones. The ternary solar cell with minimum voltage losses was developed by combining two donor materials with same ionization potential and positive ICT energy while featuring complementary optical absorption. Furthermore, the fullerene acceptor was chosen so that the energy of the positive ICT state of the two donor polymers is equal to the energy of negative ICT state of the fullerene, which can enhance dissociation of all polymer donor and fullerene acceptor excitons and suppress bimolecular and trap-assistant recombination.

    Rapid development of non-fullerene acceptors in the last two years affords more recipes of designing both efficient and stabile OSC. We show in this thesis how non-fullerene acceptors successfully can be used to design ternary solar cells with both enhanced efficiency and thermal stability. Besides improving the efficiency of the devices, understanding of the stability and degradation mechanism is another key issue. The degradation of conjugated molecules/polymers often follow many complicated pathways and at the same time many factors for degradation are coupled with each other. Therefore, the degradation of non-fullerene acceptors was investigated in darkness by photoelectron spectroscopy in this thesis with the in-situ method of controlling exposure of O2 and water vapor separately.

    List of papers
    1. Low Band Gap Polymer Solar Cells With Minimal Voltage Losses
    Open this publication in new window or tab >>Low Band Gap Polymer Solar Cells With Minimal Voltage Losses
    Show others...
    2016 (English)In: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 6, no 18, 1600148Article in journal (Refereed) Published
    Abstract [en]

    One of the factors limiting the performance of organic solar cells (OSCs) is their large energy losses (E-loss) in the conversion from photons to electrons, typically believed to be around 0.6 eV and often higher than those of inorganic solar cells. In this work, a novel low band gap polymer PIDTT-TID with a optical gap of 1.49 eV is synthesized and used as the donor combined with PC 71 BM in solar cells. These solar cells attain a good power conversion efficiency of 6.7% with a high open-circuit voltage of 1.0 V, leading to the E-loss as low as 0.49 eV. A systematic study indicates that the driving force in this donor and acceptor system is sufficient for charge generation with the low E-loss. This work pushes the minimal E-loss of OSCs down to 0.49 eV, approaching the values of some inorganic and hybrid solar cells. It indicates the potential for further enhancement of the performance of OSCs by improving their V-oc since the E-loss can be minimized.

    Place, publisher, year, edition, pages
    WILEY-V C H VERLAG GMBH, 2016
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-133010 (URN)10.1002/aenm.201600148 (DOI)000387132200002 ()
    Note

    Funding Agencies|Swedish Research Council; Swedish Research Council Formas; Swedish Energy Agency; Chalmers Area of Advance Energy and Materials Science; EU projects SUNFLOWER-"SUstainable Novel FLexible Organic Watts Efficiently Reliable" [287594]; Knut and Alice Wallenberg foundation; program for the Excellent Doctoral Dissertations of Guangdong Province [ybzzxm201114]; China Scholarship Council; National Natural Science Foundation of China [21504066, 21534003]; Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy [DE-AC02-05CH11231]

    Available from: 2016-12-08 Created: 2016-12-07 Last updated: 2017-11-15
    2. Ternary organic solar cells with enhanced open circuit voltage
    Open this publication in new window or tab >>Ternary organic solar cells with enhanced open circuit voltage
    Show others...
    2017 (English)In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 37, 24-31 p.Article in journal (Refereed) Published
    Abstract [en]

    By introducing a non-fullerene small molecule acceptor as a third component to typical polymer donor: fullerene acceptor binary solar cells, we demonstrate that the short circuit current density (J(sc)), open circuit voltage (V-oc), power conversion efficiency (PCE) and thermal stability can be enhanced simultaneously. The different surface energy of each component causes most of the non-fullerene acceptor molecules to self-organize at the polymer/fullerene interface, while the appropriately selected oxidation/reduction potential of the non-fullerene acceptor enables the resulting ternary junction to work through a cascade mechanism. The cascade ternary junction enhances charge generation through complementary absorption between the non-fullerene and fullerene acceptors and aids the efficient charge extraction from fullerene domains. The bimolecular recombination in the ternary blend layer is reduced as the ternary cascade junction increases the separation of holes and electrons during charge transportation and the trap assistant recombination induced by integer charge transfer (ICT) state potentially reduced due to the smaller pinning energy of inserted non-fullerene acceptor, leading to an unprecedented increase in the open circuit voltage beyond the binary reference values.

    Place, publisher, year, edition, pages
    ELSEVIER SCIENCE BV, 2017
    Keyword
    Ternary organic solar cell; Self-organization; Higher open circuit voltage; Generality; More thermal stable
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-138887 (URN)10.1016/j.nanoen.2017.04.060 (DOI)000402704500004 ()
    Note

    Funding Agencies|Knut and Alice Wallenberg Foundation; Swedish Research Council [2013-4022]; Ministry of Science and Technology [2016YFA0200700]; NSFC [21504066, 21534003]; Goran Gustafsson Foundation for Research in Natural Sciences and Medicine; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkping University [2009 00971]; China Scholarship Council; Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy [DE-AC02-05CH11231]

    Available from: 2017-06-27 Created: 2017-06-27 Last updated: 2017-11-15
    3. Ternary Organic Solar Cells with Minimum Voltage Losses
    Open this publication in new window or tab >>Ternary Organic Solar Cells with Minimum Voltage Losses
    Show others...
    2017 (English)In: Advanced Energy Materials, ISSN 1614-6840, Vol. 7, no 21, 1700390Article in journal (Refereed) Published
    Abstract [en]

    A new strategy for designing ternary solar cells is reported in this paper. A low-bandgap polymer named PTB7-Th and a high-bandgap polymer named PBDTTS-FTAZ sharing the same bulk ionization potential and interface positive integer charge transfer energy while featuring complementary absorption spectra are selected. They are used to fabricate efficient ternary solar cells, where the hole can be transported freely between the two donor polymers and collected by the electrode as in one broadband low bandgap polymer. Furthermore, the fullerene acceptor is chosen so that the energy of the positive integer charge transfer state of the two donor polymers is equal to the energy of negative integer charge transfer state of the fullerene, enabling enhanced dissociation of all polymer donor and fullerene acceptor excitons and suppressed bimolecular and trap assistant recombination. The two donor polymers feature good miscibility and energy transfer from high-bandgap polymer of PBDTTS-FTAZ to low-bandgap polymer of PTB7-Th, which contribute to enhanced performance of the ternary solar cell.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2017
    Keyword
    binary equivalent, minimum voltage losses, same bulk and interface energy, ternary solar cells
    National Category
    Polymer Chemistry
    Identifiers
    urn:nbn:se:liu:diva-143026 (URN)10.1002/aenm.201700390 (DOI)
    Available from: 2017-11-15 Created: 2017-11-15 Last updated: 2017-11-15Bibliographically approved
    4. Pyrrolo[3,4-g]quinoxaline-6,8-dione-based conjugated copolymers for bulk heterojunction solar cells with high photovoltages
    Open this publication in new window or tab >>Pyrrolo[3,4-g]quinoxaline-6,8-dione-based conjugated copolymers for bulk heterojunction solar cells with high photovoltages
    Show others...
    2015 (English)In: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 6, no 25, 4624-4633 p.Article in journal (Refereed) Published
    Abstract [en]

    A new electron-deficient building block 5,9-di(thiophen-2-yl)-6H-pyrrolo[3,4-g]quinoxaline-6,8(7H)-dione (PQD) was synthesized via functionalizing the 6- and 7-positions of quinoxaline (Qx) with a dicarboxylic imide moiety. Side chain substitution on the PQD unit leads to good solubility which enables very high molecular weight copolymers to be attained. The fusion of two strong electron-withdrawing groups (Qx and dicarboxylic imide) makes the PQD unit a stronger electron-deficient moiety than if the unit had just one electron-withdrawing group, thus enhancing the intramolecular charge transfer between electron-rich and deficient units of the copolymer. Four PQD-based polymers were synthesized which feature deep-lying highest occupied molecular orbital (HOMO) levels and bathochromic absorption spectra when compared to PBDT-Qx and PBDT-TPD analogues. The copolymers incorporated with benzo[1,2-b:4,5-b]dithiophene (BDT) units show that the 1D and 2D structural variations of the side groups on the BDT unit are correlated with the device performance. As a result, the corresponding solar cells (ITO/PEDOT:PSS/polymer: PC71BM/LiF/Al) based on the four copolymers feature very high open-circuit voltages (V-oc) of around 1.0 V. The copolymer PBDT-PQD1 attains the best power conversion efficiency of 4.9%, owing to its relatively high absorption intensity and suitable film morphology. The structure-property correlation demonstrates that the new PQD unit is a promising electron-deficient building block for efficient photovoltaic materials with high V-oc.

    Place, publisher, year, edition, pages
    ROYAL SOC CHEMISTRY, 2015
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-120071 (URN)10.1039/c5py00394f (DOI)000356298900009 ()
    Note

    Funding Agencies|Swedish Research Council; Swedish Energy Agency; EU [287594]; China Scholarship Council; program for the Excellent Doctoral Dissertations of Guangdong Province [ybzzxm201114]

    Available from: 2015-07-06 Created: 2015-07-06 Last updated: 2017-11-15
  • Public defence: 2017-12-08 10:15 ACAS, Hus A, Linköping
    Uebel, Karl
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
    Conceptual Design of Complex Hydromechanical Transmissions2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis explores the conceptual design process of complex hydromechanical transmissions for mobile working machines. Efficient methods for design optimisation and controller development are presented to support the final concept selection.

    In the endeavour to develop new fuel-efficient driveline solutions for construction machines and off-road equipment new complex hydromechanical transmission concepts are being investigated. This pursuit is driven by stricter emission legislation, high fuel prices and a desire for a greener image both for customers and manufacturers. The trend towards more complex transmission architectures increases the need for more sophisticated product development methods. Complex multiple-mode transmissions are difficult to design and prototype and can be realised in a great number of architectures. By introducing a secondary energy storage in the machine the design space expands further for both hardware and software. There is accordingly a need for more reliable concept assessment in early design stages and the possibility to support concurrent engineering throughout the development process.

    Previous research on the design and development of hydromechanical transmissions has been limited to analysis of fixed concept designs or design optimization using very simple performance indicators. Existing methodologies for electrified on-road vehicles are not suitable for off-road working machines with hydromechanical transmissions and hydraulic energy storage.

    The proposed conceptual design process uses detailed quasi-static simulation models and targets to optimise the fuel efficiency of the specific machine specifications and operations. It is also shown how high-speed dynamic simulations can be used for controller development and hardware-in-the-loop simulations to support an efficient product design process. The methods are demonstrated for typical use cases targeting new transmission development for construction machines. Software control development is also treated using control optimisation and real-time simulation. Finally a novel hybrid hydromechanical motion system is presented for which an efficient design process is crucial to its end performance.

    List of papers
    1. Design Optimization of Complex Hydromechanical Transmissions
    Open this publication in new window or tab >>Design Optimization of Complex Hydromechanical Transmissions
    2013 (English)In: Journal of mechanical design (1990), ISSN 1050-0472, Vol. 135, no 9, 091005-1-091005-9 p.Article in journal (Refereed) Published
    Abstract [en]

    Demands for higher fuel efficiency for off-highway applications motivate manufacturers to replace existing drive transmissions with more complex, high-efficiency transmissions. Increased intelligence and more advanced architectures are, however, more difficult to design and prototype. This leads to longer product development processes and a greater need for early product evaluation. The great variety of existing concepts also requires a methodology to support the choice of architecture. This paper proposes a design methodology for complex hydromechanical transmissions based on optimization. The main objective is to maximize energy efficiency and adapt the design to suit the typical operating behavior of the application. The methodology is also implemented on a multiple mode transmission concept sui for a heavy wheel loader application. It is shown that the design of the gearbox heavily influences the energy consumption and the necessity to use optimization when designing the gearbox.

    Place, publisher, year, edition, pages
    ASME Press, 2013
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-99379 (URN)10.1115/1.4024732 (DOI)000326172400006 ()
    Available from: 2013-10-17 Created: 2013-10-17 Last updated: 2017-11-09Bibliographically approved
    2. Optimisation and Concept Sensitivity of Continuously Variable Hydromechanical Transmissions
    Open this publication in new window or tab >>Optimisation and Concept Sensitivity of Continuously Variable Hydromechanical Transmissions
    2013 (English)Conference paper, Oral presentation only (Other academic)
    Abstract [en]

    Demands for better fuel efficiency for mobile working machines motivate the manufacturers to replace existing drive transmissions with more complex, high-efficiency transmissions. Hydromechanical power-split transmissions can offer high energy efficiency throughout the speed range and allows a decoupling of the speed of the combustion engine and the vehicle speed. This paper deals with the design of complex hydromechanical power-split transmissions and suggests an optimisation-based design methodology to minimise the energy consumption and manufacturing cost of the gearbox. The methodology is applied to a multiple mode power-split transmission which is designed to suit the requirements and typical operating behaviour of a heavy wheel loader. It is shown how important the design of the transmission is to its characteristics and how manufacturing costs can be weighed against energy efficiency.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-99380 (URN)
    Conference
    8th International Conference on Fluid Power Trans- mission and Control, April 9-11, Hangzhou, China
    Available from: 2013-10-17 Created: 2013-10-17 Last updated: 2017-11-09Bibliographically approved
    3. Modular Design of Hydromechanical Transmissions for Mobile Working Machines
    Open this publication in new window or tab >>Modular Design of Hydromechanical Transmissions for Mobile Working Machines
    2013 (English)In: Proceedings of the 13th Scandinavian International Conference on Fluid Power,(SICFP2013), June 3-5, 2013, Linköping, Sweden, Linköping: Linköping University Electronic Press, 2013, 113-119 p.Conference paper, Oral presentation only (Refereed)
    Abstract [en]

    This paper demonstrates an optimisation-based method to design modular gearboxes scalable for a range of applications. The design is adapted to the typical operating behaviours of the reference vehicles and considers the manufacturing costs of the gearboxes. Hydromechanical continuously variable transmissions (CVTs) are today strong candidates to replace drive line transmissions based on fuel-thirsty torque converters in many mobile working machines. The advantages include wide range of torque/speed ratios, high energy efficiency throughout the speed range and decoupling of the engine speed and the vehicle speed. Advanced multiple mode CVTs, however, are difficult to evaluate early in the product development process due to the complex architectures and the great variety of possible concepts. There is consequently an increased need for methods to design, compare and evaluate the transmission concepts. To decrease the development and manufacturing costs, there is also a need for scalable transmission concepts that can be used in several applications of different classes. The results show the proficiency of the methodology compared to a manual design process and that the energy efficiency of the transmissions are heavy coupled to the designs.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2013
    Series
    Linköping Electronic Conference Proceedings, ISSN 1650-3686 (print), 1650-3740 (online) ; 92
    Keyword
    Hydromechanical transmissions, Power-split, Design optimisation
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-99381 (URN)10.3384/ecp1392a12 (DOI)978-91-7519-572-8 (ISBN)
    Conference
    Proceedings of the 13th Scandinavian International Conference on Fluid Power, (SICFP2013), June 3-5, 2013, Linköping, Sweden
    Available from: 2013-10-17 Created: 2013-10-17 Last updated: 2017-11-09Bibliographically approved
    4. Simulation Aided Design and Testing of Hydromechanical Transmissions
    Open this publication in new window or tab >>Simulation Aided Design and Testing of Hydromechanical Transmissions
    2014 (English)In: The 9th JFPS International Symposium on Fluid Power, Matsue, 2014, 2014Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper demonstrates the use of high-speed simulation in transmission conceptual design and presents a transmission test bed for hardware-in-the-loop simulations of hydromechanical transmission concepts. Complex transmissions, such as multiple-mode hydromechanical transmissions and hydraulic hybrid transmissions, present new difficulties and costs in the development process. There is today a greater demand for more efficient product development and more work has shifted towards simulation. The Hopsan simulation package allows robust, high-speed simulations suitable for both offline and hardware-in-the-loop simulation. New simulation models for hydromechanical transmissions are developed and used to simulate a known two-mode transmission concept. The same concept is also tested in hardware-in-the-loop simulations in the proposed transmission test bed. Results show good agreement with the hardware tests and highlight the proficiency of the simulation tools.

    Keyword
    Hydromechanical Transmission, Hardware-in-the-loop, Hopsan
    National Category
    Aerospace Engineering
    Identifiers
    urn:nbn:se:liu:diva-126561 (URN)4-931070-10-8 (ISBN)
    Conference
    the 9th JFPS International Symposium on Fluid Power in Matsue, Shimane Japan, on October 28-31, 2014
    Available from: 2016-03-30 Created: 2016-03-30 Last updated: 2017-11-09
    5. Mode Shifting in Hybrid Hydromechanical Transmissions
    Open this publication in new window or tab >>Mode Shifting in Hybrid Hydromechanical Transmissions
    2015 (English)In: ASME/BATH 2015 Symposium on Fluid Power and Motion Control, ASME Press, 2015, 13- p.Conference paper, Published paper (Refereed)
    Abstract [en]

    Demands for low cost sustainable solutions have increased the use of and interest in complex hydromechanical transmissions for heavy off-road vehicles. In transmissions with multiplemodes, an important condition is to maintain the tractive force during the mode shifting event. For hybrid hydromechanical transmissions, with a direct connection to a hydraulic accumulator, the impressed system pressure caused by the hydraulic accumulator has not yet been observed to interfere with this condition. In this paper, a black box model approach is used to modify the hydraulic system after obtaining knowledge regarding how it is affected by a mode shift. A comparative study is carried out where a full vehicle model of a mobile working machine is simulated with two different hydraulic systems. The results show that different system solutions imply different demands on the included components, and that the mode shifting event is not a negligible factor in heavy hydraulic hybrid vehicles.

    Place, publisher, year, edition, pages
    ASME Press, 2015
    Keyword
    Mode shifting, hydromechanical transmissions, fluid power, heavy construction machinery
    National Category
    Other Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-126556 (URN)10.1115/FPMC2015-9583 (DOI)000373970500045 ()978-0-7918-5723-6 (ISBN)
    Conference
    ASME/BATH 2015 Symposium on Fluid Power and Motion Control, Chicago, Illinois, USA, October 12–14, 2015
    Projects
    Research on Hydromechanical Transmissions and Hybrid Motion systems, RHYTHM
    Funder
    Swedish Energy Agency, P39367-1
    Available from: 2016-03-30 Created: 2016-03-30 Last updated: 2017-11-09
    6. A novel hydromechanical hybrid motion system for construction machines
    Open this publication in new window or tab >>A novel hydromechanical hybrid motion system for construction machines
    2017 (English)In: International Journal of Fluid Power, ISSN 1439-9776, Vol. 18, no 1, 17-28 p.Article in journal (Refereed) Published
    Abstract [en]

    This paper deals with a novel type of hybrid motion system for construction machines based on a common pressure rail shared between a hydromechanical power-split transmission and secondary controlled work hydraulics. A construction machine with driveline and work functions is a complex coupled motion system and the design of an effective hybrid system needs to take both subsystems into account. Studies on energy efficient hybrid systems for construction machines have hitherto principally focused on one subsystem at a time - work hydraulics or driveline. The paper demonstrates a use case with a specific transmission concept proposal for a medium-sized wheel loader. The system is modelled and simulated using an optimal energy management strategy based on dynamic programming. The results show the benefits of a throttle-free bidirectional link between the machine's subsystems and the energy storage, while taking advantage of the complex power flows of the power-split transmission.

    Place, publisher, year, edition, pages
    Abingdon, UK: Taylor & Francis, 2017
    National Category
    Mechanical Engineering
    Identifiers
    urn:nbn:se:liu:diva-142329 (URN)10.1080/14399776.2016.1210423 (DOI)
    Available from: 2017-10-26 Created: 2017-10-26 Last updated: 2017-11-09Bibliographically approved
  • Public defence: 2017-12-08 13:00 Berzeliussalen, ingång 65, Linköping
    Emilsson, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Center for Social and Affective Neuroscience. Linköping University, Faculty of Medicine and Health Sciences. Department of Health Science, University West, Trollhättan, Sweden.
    Treatment adherence in Asthma and Attention Deficit Hyperactivity Disorder (ADHD), Personality traits, Beliefs about medication and Illness perception2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Adherence to medication in asthma and attention deficit hyperactivity disorder (ADHD) is important because medication may prevent serious consequences, possibly with lifelong effects. Several factors have been identified that influence adherence to medication in these disorders, but the importance of personality traits, beliefs about medication and illness perception has been insufficiently explored.

    The overall aim of this thesis was to study adherence to medication in asthma and ADHD, and in particular factors associated with adherence.

    The participants (n=268) in Study I were recruited epidemiologically and consisted of young adults with asthma, aged 22 years (±1 year). Impulsivity and, in men Antagonism and Alexithymia were associated with low adherence among respondents with regular asthma medication (n=109).

    The participants (n=35) in Study II were recruited from primary care clinics and consisted of adults (mean age 53 years). In men, Neuroticism was associated with low adherence, but Conscientiousness with high adherence. Beliefs about the necessity of medication were positively associated with adherence behaviour in women. In the total sample, a positive necessity-concern differential of beliefs predicted higher adherence.

    The participants in Study III, IV (n=101) and V (n=99) were recruited from Child and Adolescent Psychiatric clinics and consisted of adolescents with ADHD on long-term ADHD medication. Study IV assessed the reliability and validity of Swedish translations of the Beliefs about Medicines Questionnaire-specific (BMQ-Specific) and Brief Illness Perception Questionnaire (B-IPQ) for use in adolescents with ADHD. Exploratory Principal Component Analysis (PCA) loadings of the BMQ-Specific items confirmed the original components, the specific-necessity and specific-concerns. The exploratory PCA for B-IPQ revealed two components; the first one, B-IPQ Consequences, captured questions regarding perceptions of the implication of having ADHD (items 1, 2, 5, 6 and 8) and the second one, B-IPQ-Control, the perceptions of the ability to manage the ADHD disorder (items 3, 4 and 7). Adherence correlated positively with BMQ-necessity-concern differential but negatively with beliefs about medication regarding concerns and side effects as well as Antagonism. Adolescents with more beliefs in the necessity, but with less concerns and side effects were less intentionally non-adherent. Adolescents with more perceptions that ADHD affected life showed less unintentional non-adherence. Negative Affectivity was associated with beliefs in the necessity of medication, but also with concern about medication and side effects. Negative Affectivity was positively associated with perceived consequences in life caused by ADHD and less control over ADHD. Hedonic Capacity was associated with less concerns about medication.

    In conclusion: In asthma and ADHD, adherence was associated with personality and beliefs about medications treatment. The personality traits showed numerous associations with perception about ADHD and beliefs about asthma and ADHD medication. This thesis increases our understanding of these person-related underlying factors of non-adherence, which may enable targeted actions intended to turn non-adherence into adherence as well as to identify individuals at risk for non-adherence. The Swedish translation of BMQ-Specific and B-IPQ proved to be valid and reliable, suggesting that the scales are useful in clinical work to identify risks of low adherence and to increase knowledge about how adolescents perceive ADHD. 

    List of papers
    1. Personality, adherence, asthma control and health-related quality of life in young adult asthmatics
    Open this publication in new window or tab >>Personality, adherence, asthma control and health-related quality of life in young adult asthmatics
    Show others...
    2009 (English)In: Respiratory Medicine, ISSN 0954-6111, E-ISSN 1532-3064, Vol. 103, no 7, 1033-1040 p.Article in journal (Refereed) Published
    Abstract [en]

    Background

    Striving for improved adherence and asthma control is of vital concern in today's asthma management. Several influential factors have been identified, but the importance of personality traits has been insufficiently explored. The aim was first to determine whether personality traits in young adult asthmatics are related to asthma control and health-related quality of life (HRQL), and second to examine the influences of personality traits on adherence to regular asthma medication treatment.

    Methods

    Young adult asthmatics, 22 years of age (n = 268) completed questionnaires. Statistical analyses were performed.

    Results

    The personality traits Negative Affectivity and Impulsivity correlated negatively with asthma control, whereas in women Hedonic Capacity correlated positively with asthma control. Negative Affectivity, Impulsivity, Hedonic Capacity, Alexithymia and asthma control predicted the mental dimension of HRQL. Asthma control and physical activity predicted the physical dimension of HRQL. Among respondents with regular asthma medication (n = 109), Impulsivity correlated negatively with adherence. In men, Antagonism and Alexithymia were associated with low adherence. Additionally, Alexithymia, Hedonic Capacity and Negative Affectivity showed non-linear relationships with adherence, meaning that initially increased scores on these personality traits scales were associated with increased adherence but higher scores did not increase adherence. Respondents who were prescribed a single inhaler combining ICS and LABA reported higher adherence than those with monotherapies.

    Conclusion

    These data suggest that personality can influence how asthma patients adhere to asthma medication treatment, and report their control and HRQL. Tools determining personality traits may be useful in the future in individualizing management of asthma patients.

    Place, publisher, year, edition, pages
    Elsevier, 2009
    Keyword
    Adherence, Asthma, Asthma control, Health-related quality of life, Personality traits, Young adults
    National Category
    Nursing
    Research subject
    NURSING AND PUBLIC HEALTH SCIENCE, Nursing science
    Identifiers
    urn:nbn:se:liu:diva-142758 (URN)10.1016/j.rmed.2009.01.013 (DOI)09546111 (ISSN) (ISBN)
    Available from: 2009-09-21 Created: 2017-11-02 Last updated: 2017-11-02Bibliographically approved
    2. The Influence of personality traits and beliefs about medicines on adherence to asthma treatment
    Open this publication in new window or tab >>The Influence of personality traits and beliefs about medicines on adherence to asthma treatment
    Show others...
    2011 (English)In: Primary Care Respiratory Journal, ISSN 1471-4418, E-ISSN 1475-1534, Vol. 20, no 2, 141-147 p.Article, review/survey (Refereed) Published
    Abstract [en]

    Aim:To explore the influence of personality traits and beliefs about medicines on adherence to treatment with asthma medication.

    Methods:Respondents were 35 asthmatic adults prescribed controller medication. They answered questionnaires about medication adherence, personality traits, and beliefs about medicines.

    Results:In gender comparisons, the personality traits “Neuroticism” in men and “adherence to medication” were associated with lower adherent behaviour. Associations between personality traits and beliefs in the necessity of medication for controlling the illness were identified. Beliefs about the necessity of medication were positively associated with adherent behaviour in women. In the total sample, a positive “necessity-concern” differential predicted adherent behaviour.

    Conclusion:The results imply that personality and beliefs about medicines may influence how well adults with asthma adhere to treatment with asthma medication.

    Place, publisher, year, edition, pages
    The Primary Care Respiratory Society U K, 2011
    Keyword
    adherence, asthma, medication beliefs, personality traits, treatment
    National Category
    Nursing
    Research subject
    NURSING AND PUBLIC HEALTH SCIENCE, Nursing science
    Identifiers
    urn:nbn:se:liu:diva-142759 (URN)10.4104/pcrj.2011.00005 (DOI)
    Available from: 2011-02-18 Created: 2017-11-02 Last updated: 2017-11-02Bibliographically approved
    3. Beliefs regarding medication and side effects influence treatment adherence in adolescents with attention deficit hyperactivity disorder
    Open this publication in new window or tab >>Beliefs regarding medication and side effects influence treatment adherence in adolescents with attention deficit hyperactivity disorder
    2017 (English)In: European Child and Adolescent Psychiatry, ISSN 1018-8827, E-ISSN 1435-165X, Vol. 26, no 5, 559-571 p.Article in journal (Refereed) Published
    Abstract [en]

    Adherence to attention deficit hyperactivity disorder (ADHD) treatment is important because, when untreated, it may have serious consequences with lifelong effects. In the case of adolescents on long-term medicine prescription, more knowledge is needed regarding adherence and factors influencing adherence, which was the purpose of this study. Adolescents (n = 101) on ADHD medication ≥6 months were administrated questionnaires at a monitoring appointment: Medication Adherence Report Scale (MARS), beliefs about medicines (BMQ) and the Brief Illness Perception Questionnaire (B-IPQ). Adherence was high, the mean value was 88% of the maximum MARS score, and correlated positively with the “BMQ-necessity-concerns differential” but negatively with “BMQ-concerns” and “BMQ-side effects”. Adolescents with more belief in the necessity of the medication, less concerns and less experience of side effects tended to be more adherent to medication prescription (“intentional non-adherence”), while “unintentional non-adherence” (forgetfulness) was associated with how much they perceived that their ADHD affected their lives. In a multiple regression model, the variance of MARS total (R2 = 0.21) and “intentional non-adherence” (R2 = 0.24) was explained by the “BMQ-necessity–concern differential” and “BMQ-experienced side effects”. The variance of “unintentional non-adherence” (R2 = 0.12) was explained by the “BMQ-necessity–concern differential” and “B-IPQ-consequences of ADHD”. In conclusion, adolescents on long-term medication reported good adherence, mainly influenced by more beliefs in the necessity versus concerns of the medications, less experienced side effects and more perceived consequences of ADHD. BMQ could be useful to identify risks of low adherence, which should be counteracted by partially gender-specific interventions.

    Place, publisher, year, edition, pages
    Springer, 2017
    Keyword
    Electron beam melting, IN718, microstructure, texture, hardness
    National Category
    Psychiatry
    Identifiers
    urn:nbn:se:liu:diva-132825 (URN)10.1007/s00787-016-0919-1 (DOI)000399701900007 ()27848023 (PubMedID)
    Note

    Funding agencies: Medical Research Council of Southeast Sweden [FORSS-466211]; "Child and Youth Studies" at the University West

    Available from: 2016-11-30 Created: 2016-11-30 Last updated: 2017-11-02Bibliographically approved
  • Public defence: 2017-12-12 10:00 Planck, Fysikhuset, Linköping
    Mickan, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Deposition of Al-doped ZnO films by high power impulse magnetron sputtering2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Transparent conducting oxides (TCOs) are an important class of materials with many applications such as low emissivity coatings, or transparent electrodes for photovoltaics and flat panel displays. Among the possible TCO materials, Al-doped ZnO (AZO) is studied due to its relatively low cost and abundance of the raw materials. Thin films of AZO are commonly produced using physical vapour deposition techniques such as magnetron sputtering. However, there is a problem with the homogeneity of the films using reactive direct current magnetron sputtering (DCMS). This homogeneity problem can be related to the bombardment of the growing film with negative oxygen ions, that can cause additional acceptor defects and the formation of insulating secondary phases. In this work AZO films are deposited by high power impulse magnetron sputtering (HiPIMS), a technique in which high instantaneous current densities are achieved by short pulses of low duty cycle.

    In the first part of this thesis, the possibility to improve the homogeneity of the deposited AZO films by using HiPIMS is demonstrated. This improvement can be related to the high instantaneous sputtering rate during the HiPIMS pulses, so the process can take place in the metal mode. This allows for a lower oxygen ion bombardment of the growing film, which can help to avoid the formation of secondary phases. Another problem of AZO is the stability of the properties in humid environments. To assess this problem, the degradation of the electrical properties after an aging procedure was investigated for films deposited by both DCMS and by HiPIMS. A method was proposed, to restore the properties of the films, using a low temperature annealing under N2 atmosphere. The improvement of the electrical properties of the films could be related to a diffusion process, where water is diffusing out of the films. Then, the influence of the substrate temperature on the properties of AZO films deposited by HiPIMS was studied. The electrical, optical and structural properties were found to improve with increasing substrate temperature up to 600 C. This improvement can be mostly explained by the increase in crystalline quality and the annealing of defects. Finally, the deposition of AZO films on flexible PET substrates was investigated. The films are growing as a thick porous layer of preferentially c-axis oriented columns on top of a thin dense seed layer. The evolution of the sheet resistance of the films after bending the films with different radii was studied. There is an increase in the sheet resistance of the films with decreasing bending radius, that is less pronounced for thicker films.

    List of papers
    1. Room temperature deposition of homogeneous, highly transparent and conductive Al-doped ZnO films by reactive high power impulse magnetron sputtering
    Open this publication in new window or tab >>Room temperature deposition of homogeneous, highly transparent and conductive Al-doped ZnO films by reactive high power impulse magnetron sputtering
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    2016 (English)In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 157, 742-749 p.Article in journal (Refereed) Published
    Abstract [en]

    Aluminum doped zinc oxide (AZO) films have been deposited using reactive high power impulse magnetron sputtering (HiPIMS) and reactive direct current (DC) magnetron sputtering from an alloyed target without thermal assistance. These films have been compared in terms of their optical, electrical and structural properties. While both DC and HiPIMS deposited films show comparable transmittance, their electrical properties are significantly improved by the HiPIMS process. The HiPIMS deposited films show a low resistivity down to the order of 10(-4) Omega cm with a good homogeneity across the substrate, making them potential candidates for electrodes in solar cells. The density of electrons reached up to 11 x 10(20) cm(-3), making ionized impurities the main scattering defects. This improvement of the film properties can be related to the specific plasma/target interactions in a HiPIMS discharge. This allows the process to take place in the transition mode and to deposit highly conductive, transparent AZO films on large surfaces at low temperature. While the overall oxygen content is above that of stoichiometric ZnO, higher localization of oxygen is found at the interfaces between crystalline domains with substoichiometric composition. (C) 2016 Elsevier B.V. All rights reserved.

    Place, publisher, year, edition, pages
    ELSEVIER SCIENCE BV, 2016
    Keyword
    Transparent conducting oxide; AZO; Thin films; Electronic properties; HiPIMS
    National Category
    Condensed Matter Physics
    Identifiers
    urn:nbn:se:liu:diva-132201 (URN)10.1016/j.solmat.2016.07.020 (DOI)000384391700088 ()
    Note

    Funding Agencies|European Commission within the DocMASE project

    Available from: 2016-11-01 Created: 2016-10-21 Last updated: 2017-11-10
    2. Restoring the Properties of Transparent Al-Doped ZnO Thin Film Electrodes Exposed to Ambient Air
    Open this publication in new window or tab >>Restoring the Properties of Transparent Al-Doped ZnO Thin Film Electrodes Exposed to Ambient Air
    Show others...
    2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 27, 14426-14433 p.Article in journal (Refereed) Published
    Abstract [en]

    The properties of Al-doped ZnO (AZO) films are known to degrade with exposure to humidity. Different AZO films deposited using reactive direct current magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS) have been aged in ambient laboratory conditions and annealed at temperatures between 160 and 180 degrees C in a N-2 atmosphere. Their electrical and optical properties, which have been investigated both ex situ and in situ during the annealing, are improved. The results of the in situ measurements are interpreted in terms of a diffusion process, where hydroxyl groups are decomposed and water is diffusing out of the films. As hydroxyl groups are known to act as a trap for charge carriers in ZnO, their removal from the film can explain the improvement of the electrical properties by the annealing.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 2017
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-139560 (URN)10.1021/acs.jpcc.7b03020 (DOI)000405761600006 ()
    Note

    Funding Agencies|European Commission

    Available from: 2017-08-08 Created: 2017-08-08 Last updated: 2017-11-10
  • Public defence: 2017-12-12 13:15 Ada Lovelace,, Linköping
    Linders, Viktor
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Error analysis of summation-by-parts formulations: Dispersion, transmission and accuracy2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis we consider errors arising from finite difference operators on summation-by-parts (SBP) form, used in the discretisation of partial differential equations. The SBP operators are augmented with simultaneous-approximation-terms (SATs) to weakly impose boundary conditions. The SBP-SAT framework combines high order of accuracy with a systematic construction of provably stable boundary procedures, which renders it suitable for a wide range of problems.

    The first part of the thesis treats wave propagation problems discretised using SBP operators on coarse grids. Unless special care is taken, inaccurate approximations of the underlying dispersion relation materialises in the form of an incorrect propagation speed. We present a procedure for constructing SBP operators with minimal dispersion error. Experiments indicate that they outperform higher order non-optimal SBP operators for flow problems involving high frequencies and long simulation times.

    In the second part of the thesis, the formal order of accuracy of SBP operators near boundaries is analysed. We prove that the order in the interior of a diagonal norm based SBP operator must be at least twice that of the boundary stencil, irrespective of the grid point distribution near the boundary. This generalises the classical theory posed on uniform and conforming grids. We further show that for a common class of SBP operators, the diagonal norm defines a quadrature rule of the same order as the interior stencil. Again, this result is independent of the grid.

    In the final contribution if the thesis, we introduce the notion of a transmission problem to describe a general class of problems where different dynamics are coupled in time. Well-posedness and stability analyses are performed for continuous and discrete problems. A general condition is obtained that is necessary and sufficient for the transmission problem to satisfy an energy estimate. The theory provides insights into the coupling of fluid flow models, multi-block formulations, numerical filters, interpolation and multi-grid implementations.

    List of papers
    1. Uniformly Best Wavenumber Approximations by Spatial Central Difference Operators
    Open this publication in new window or tab >>Uniformly Best Wavenumber Approximations by Spatial Central Difference Operators
    2015 (English)In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 300, 695-709 p.Article in journal (Refereed) Published
    Abstract [en]

    We construct accurate central difference stencils for problems involving high frequency waves or multi-frequency solutions over long time intervals with a relatively coarse spatial mesh, and with an easily obtained bound on the dispersion error. This is done by demonstrating that the problem of constructing central difference stencils that have minimal dispersion error in the infinity norm can be recast into a problem of approximating a continuous function from a finite dimensional subspace with a basis forming a Chebyshev set. In this new formulation, characterising and numerically obtaining optimised schemes can be done using established theory.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keyword
    Dispersion relation; Wave propagation; Wavenumber approximation; Finite differences; Approximation theory
    National Category
    Computational Mathematics
    Identifiers
    urn:nbn:se:liu:diva-120896 (URN)10.1016/j.jcp.2015.08.005 (DOI)000361573200035 ()
    Available from: 2015-08-28 Created: 2015-08-28 Last updated: 2017-11-20Bibliographically approved
    2. A simple and efficient incompressible Navier-Stokes solver for unsteady complex geometry flows on truncated domains
    Open this publication in new window or tab >>A simple and efficient incompressible Navier-Stokes solver for unsteady complex geometry flows on truncated domains
    Show others...
    2017 (English)In: Computers & Fluids, ISSN 0045-7930, E-ISSN 1879-0747, Vol. 150, 84-94 p.Article in journal (Refereed) Published
    Abstract [en]

    Incompressible Navier-Stokes solvers based on the projection method often require an expensive numerical solution of a Poisson equation for a pressure-like variable. This often involves linear system solvers based on iterative and multigrid methods which may limit the ability to scale to large numbers of processors. The artificial compressibility method (ACM) [6] introduces a time derivative of the pressure into the incompressible form of the continuity equation creating a coupled closed hyperbolic system that does not require a Poisson equation solution and allows for explicit time-marching and localized stencil numerical methods. Such a scheme should theoretically scale well on large numbers of CPUs, GPU'€™s, or hybrid CPU-GPU architectures. The original ACM was only valid for steady flows and dual-time stepping was often used for time-accurate simulations. Recently, Clausen [7] has proposed the entropically damped artificial compressibility (EDAC) method which is applicable to both steady and unsteady flows without the need for dual-time stepping. The EDAC scheme was successfully tested with both a finite-difference MacCormack'€™s method for the two-dimensional lid driven cavity and periodic double shear layer problem and a finite-element method for flow over a square cylinder, with scaling studies on the latter to large numbers of processors. In this study, we discretize the EDAC formulation with a new optimized high-order centered finite-difference scheme and an explicit fourth-order Runge-€“Kutta method. This is combined with an immersed boundary method to efficiently treat complex geometries and a new robust outflow boundary condition to enable higher Reynolds number simulations on truncated domains. Validation studies for the Taylor-€“Green Vortex problem and the lid driven cavity problem in both 2D and 3D are presented. An eddy viscosity subgrid-scale model is used to enable large eddy simulations for the 3D cases. Finally, an application to flow over a sphere is presented to highlight the boundary condition and performance comparisons to a traditional incompressible Navier-€“Stokes solver is shown for the 3D lid driven cavity. Overall, the combined EDAC formulation and discretization is shown to be both effective and affordable.

    Place, publisher, year, edition, pages
    Elsevier, 2017
    Keyword
    Artificial compressibility method, EDAC, High-order numerical methods, Large Eddy simulation
    National Category
    Computational Mathematics
    Identifiers
    urn:nbn:se:liu:diva-136507 (URN)10.1016/j.compfluid.2017.03.030 (DOI)000401219000007 ()
    Note

    Funding agencies: Rosenblatt Chair within the faculty of Mechanical Engineering; Zeff Fellowship Trust

    Available from: 2017-04-19 Created: 2017-04-19 Last updated: 2017-11-20Bibliographically approved
    3. Summation-by-Parts Operators with Minimal Dispersion Error for Coarse Grid Flow Calculations
    Open this publication in new window or tab >>Summation-by-Parts Operators with Minimal Dispersion Error for Coarse Grid Flow Calculations
    2017 (English)In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 340, 34 p.160-176 p.Article in journal (Refereed) Published
    Abstract [en]

    We present a procedure for constructing Summation-by-Parts operators with minimal dispersion error both near and far from numerical interfaces. Examples of such operators are constructed and compared with a higher order non-optimised Summation-by-Parts operator. Experiments show that the optimised operators are superior for wave propagation and turbulent flows involving large wavenumbers, long solution times and large ranges of resolution scales.

    Place, publisher, year, edition, pages
    Elsevier, 2017. 34 p.
    Keyword
    Summation-by-Parts, Dispersion relation, Finite differences, Wave Propagation
    National Category
    Computational Mathematics
    Identifiers
    urn:nbn:se:liu:diva-136474 (URN)10.1016/j.jcp.2017.03.039 (DOI)000401137900009 ()
    Available from: 2017-04-12 Created: 2017-04-12 Last updated: 2017-11-20Bibliographically approved
    4. On the order of Accuracy of Finite Difference Operators on Diagonal Norm Based Summation-By-Parts Form
    Open this publication in new window or tab >>On the order of Accuracy of Finite Difference Operators on Diagonal Norm Based Summation-By-Parts Form
    2017 (English)Report (Other academic)
    Abstract [en]

    In this paper we generalise results regarding the order of accuracy of finite difference operators on Summation-By-Parts (SBP) form, previously known to hold on uniform grids, to grids with arbitrary point distributions near domain boundaries. We give a definite proof that the order of accuracy in the interior of a diagonal norm based SBP operator must be at least twice that of the boundary stencil, irrespective of the grid point distribution near the boundary. Additionally, we prove that if the order of accuracy in the interior is precisely twice that of the boundary, then the diagonal norm defines a quadrature rule of the same order as the interior stencil. Again, this result is independent of the grid point distribution near the domain boundaries.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2017. 15 p.
    Series
    LiTH-MAT-R, ISSN 0348-2960 ; 2017:11
    Keyword
    Finite difference schemes, summation-by-parts operators, numerical differentiation, quadrature rules, order of accuracy
    National Category
    Computational Mathematics
    Identifiers
    urn:nbn:se:liu:diva-140815 (URN)
    Available from: 2017-09-12 Created: 2017-09-12 Last updated: 2017-11-20Bibliographically approved
    5. Well-posed and Stable Transmission Problems
    Open this publication in new window or tab >>Well-posed and Stable Transmission Problems
    2017 (English)Report (Other academic)
    Abstract [en]

    We introduce the notion of a transmission problem to describe a general class of problems where different dynamics are coupled in time. Well-posedness and stability is analysed for continuous and discrete problems using both strong and weak formulations, and a general transmission condition is obtained. The theory is applied to several examples including the coupling of fluid flow models, multi-grid implementations, multi-block formulations and numerical filtering.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2017. 28 p.
    Series
    LiTH-MAT-R, ISSN 0348-2960 ; 15
    Keyword
    Initial-boundary value problems, Transmission problems, Energy estimates, Well-posedness, Multi-block, Numerical Filter. Interpolation, Multi-grid, Summation-by-Parts, Stability
    National Category
    Computational Mathematics
    Identifiers
    urn:nbn:se:liu:diva-142348 (URN)LiTH-MAT-R--2017/15--SE (ISRN)
    Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2017-11-20Bibliographically approved
  • Public defence: 2017-12-13 09:00 Berzeliussalen, Linköping
    Blystad, Ida
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Clinical Applications of Synthetic MRI of the Brain2017Doctoral thesis, comprehensive summary (Other academic)
    List of papers
    1. Synthetic MRI of the brain in a clinical setting
    Open this publication in new window or tab >>Synthetic MRI of the brain in a clinical setting
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    2012 (English)In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 53, no 10, 1158-1163 p.Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND:

    Conventional magnetic resonance imaging (MRI) has relatively long scan times for routine examinations, and the signal intensity of the images is related to the specific MR scanner settings. Due to scanner imperfections and automatic optimizations, it is impossible to compare images in terms of absolute image intensity. Synthetic MRI, a method to generate conventional images based on MR quantification, potentially both decreases examination time and enables quantitative measurements.

    PURPOSE:

    To evaluate synthetic MRI of the brain in a clinical setting by assessment of the contrast, the contrast-to-noise ratio (CNR), and the diagnostic quality compared with conventional MR images.

    MATERIAL AND METHODS:

    Twenty-two patients had synthetic imaging added to their clinical MR examination. In each patient, 12 regions of interest were placed in the brain images to measure contrast and CNR. Furthermore, general image quality, probable diagnosis, and lesion conspicuity were investigated.

    RESULTS:

    Synthetic T1-weighted turbo spin echo and T2-weighted turbo spin echo images had higher contrast but also a higher level of noise, resulting in a similar CNR compared with conventional images. Synthetic T2-weighted FLAIR images had lower contrast and a higher level of noise, which led to a lower CNR. Synthetic images were generally assessed to be of inferior image quality, but agreed with the clinical diagnosis to the same extent as the conventional images. Lesion conspicuity was higher in the synthetic T1-weighted images, which also had a better agreement with the clinical diagnoses than the conventional T1-weighted images.

    CONCLUSION:

    Synthetic MR can potentially shorten the MR examination time. Even though the image quality is perceived to be inferior, synthetic images agreed with the clinical diagnosis to the same extent as the conventional images in this study.

    Place, publisher, year, edition, pages
    Sage Publications, 2012
    Keyword
    CNS, MR imaging, brain, technology assessment, imaging sequences
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-89641 (URN)10.1258/ar.2012.120195 (DOI)000314077400015 ()23024181 (PubMedID)
    Available from: 2013-02-28 Created: 2013-02-28 Last updated: 2017-11-16Bibliographically approved
    2. Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent
    Open this publication in new window or tab >>Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent
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    2016 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 37, no 1, 94-100 p.Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND AND PURPOSE: Contrast-enhancing MS lesions are important markers of active inflammation in the diagnostic work-up of MS and in disease monitoring with MR imaging. Because intravenous contrast agents involve an expense and a potential risk of adverse events, it would be desirable to identify active lesions without using a contrast agent. The purpose of this study was to evaluate whether pre-contrast injection tissue-relaxation rates and proton density of MS lesions, by using a new quantitative MR imaging sequence, can identify active lesions. MATERIALS AND METHODS: Forty-four patients with a clinical suspicion of MS were studied. MR imaging with a standard clinical MS protocol and a quantitative MR imaging sequence was performed at inclusion (baseline) and after 1 year. ROIs were placed in MS lesions, classified as nonenhancing or enhancing. Longitudinal and transverse relaxation rates, as well as proton density were obtained from the quantitative MR imaging sequence. Statistical analyses of ROI values were performed by using a mixed linear model, logistic regression, and receiver operating characteristic analysis. RESULTS: Enhancing lesions had a significantly (P &lt; .001) higher mean longitudinal relaxation rate (1.22 0.36 versus 0.89 +/- 0.24), a higher mean transverse relaxation rate (9.8 +/- 2.6 versus 7.4 +/- 1.9), and a lower mean proton density (77 +/- 11.2 versus 90 +/- 8.4) than nonenhancing lesions. An area under the receiver operating characteristic curve value of 0.832 was obtained. CONCLUSIONS: Contrast-enhancing MS lesions often have proton density and relaxation times that differ from those in nonenhancing lesions, with lower proton density and shorter relaxation times in enhancing lesions compared with nonenhancing lesions.

    Place, publisher, year, edition, pages
    AMER SOC NEURORADIOLOGY, 2016
    National Category
    Clinical Medicine
    Identifiers
    urn:nbn:se:liu:diva-124482 (URN)10.3174/ajnr.A4501 (DOI)000367466500019 ()26471751 (PubMedID)
    Note

    Funding Agencies|National Science and Engineering Research Council; University of Linkoping; University Hospital Research Funds

    Available from: 2016-02-02 Created: 2016-02-01 Last updated: 2017-11-16
    3. Quantitative MRI for analysis of peritumoral edema in malignant gliomas
    Open this publication in new window or tab >>Quantitative MRI for analysis of peritumoral edema in malignant gliomas
    Show others...
    2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 5, e0177135Article in journal (Refereed) Published
    Abstract [en]

    Background and purpose Damage to the blood-brain barrier with subsequent contrast enhancement is a hallmark of glioblastoma. Non-enhancing tumor invasion into the peritumoral edema is, however, not usually visible on conventional magnetic resonance imaging. New quantitative techniques using relaxometry offer additional information about tissue properties. The aim of this study was to evaluate longitudinal relaxation R-1, transverse relaxation R-2, and proton density in the peritumoral edema in a group of patients with malignant glioma before surgery to assess whether relaxometry can detect changes not visible on conventional images. Methods In a prospective study, 24 patients with suspected malignant glioma were examined before surgery. A standard MRI protocol was used with the addition of a quantitative MR method (MAGIC), which measured R-1, R-2, and proton density. The diagnosis of malignant glioma was confirmed after biopsy/surgery. In 19 patients synthetic MR images were then created from the MAGIC scan, and ROIs were placed in the peritumoral edema to obtain the quantitative values. Dynamic susceptibility contrast perfusion was used to obtain cerebral blood volume (rCBV) data of the peritumoral edema. Voxel-based statistical analysis was performed using a mixed linear model. Results R-1, R-2, and rCBV decrease with increasing distance from the contrast-enhancing part of the tumor. There is a significant increase in R1 gradient after contrast agent injection (Pamp;lt;.0001). There is a heterogeneous pattern of relaxation values in the peritumoral edema adjacent to the contrast-enhancing part of the tumor. Conclusion Quantitative analysis with relaxometry of peritumoral edema in malignant gliomas detects tissue changes not visualized on conventional MR images. The finding of decreasing R-1 and R-2 means shorter relaxation times closer to the tumor, which could reflect tumor invasion into the peritumoral edema. However, these findings need to be validated in the future.

    Place, publisher, year, edition, pages
    PUBLIC LIBRARY SCIENCE, 2017
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:liu:diva-138480 (URN)10.1371/journal.pone.0177135 (DOI)000402058800007 ()28542553 (PubMedID)
    Note

    Funding Agencies|Medical Research Council of Southeast Sweden [FORSS-234551]

    Available from: 2017-06-19 Created: 2017-06-19 Last updated: 2017-11-16
  • Public defence: 2017-12-14 10:15 ACAS, A-huset, Linköping
    Posadzy, Kinga
    Linköping University, Department of Management and Engineering, Economics. Linköping University, Faculty of Arts and Sciences.
    Social and Economic Factors in Decision Making under Uncertainty: Five Essays in Behavioral Economics2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The objective of this thesis is to improve the understanding of human behavior that goes beyond monetary rewards. In particular, it investigates social influences in individual’s decision making in situations that involve coordination, competition, and deciding for others. Further, it compares how monetary and social outcomes are perceived. The common theme of all studies is uncertainty. The first four essays study individual decisions that have uncertain consequences, be it due to the actions of others or chance. The last essay, in turn, uses the advances in research on decision making under uncertainty to predict behavior in riskless choices.

    The first essay, Fairness Versus Efficiency: How Procedural Fairness Concerns Affect Coordination, investigates whether preferences for fair rules undermine the efficiency of coordination mechanisms that put some individuals at a disadvantage. The results from a laboratory experiment show that the existence of coordination mechanisms, such as action recommendations, increases efficiency, even if one party is strongly disadvantaged by the mechanism. Further, it is demonstrated that while individuals’ behavior does not depend on the fairness of the coordination mechanism, their beliefs about people’s behavior do.

    The second essay, Dishonesty and Competition. Evidence from a stiff competition environment, explores whether and how the possibility to behave dishonestly affects the willingness to compete and who the winner is in a competition between similarly skilled individuals. We do not find differences in competition entry between competitions in which dishonesty is possible and in which it is not. However, we find that due to the heterogeneity in propensity to behave dishonestly, around 20% of winners are not the best-performing individuals. This implies that the efficient allocation of resources cannot be ensured in a stiff competition in which behavior is unmonitored.

    The third essay, Tracing Risky Decision Making for Oneself and Others: The Role of Intuition and Deliberation, explores how individuals make choices under risk for themselves and on behalf of other people. The findings demonstrate that while there are no differences in preferences for taking risks when deciding for oneself  and for others, individuals have greater decision error when choosing for other individuals. The differences in the decision error can be partly attributed to the differences in information processing; individuals employ more deliberative cognitive processing when deciding for themselves than when deciding for others. Conducting more information processing when deciding for others is related to the reduction in decision error.

    The fourth essay, The Effect of Decision Fatigue on Surgeons’ Clinical Decision Making, investigates how mental depletion, caused by a long session of decision making, affects surgeon’s decision to operate. Exploiting a natural experiment, we find that surgeons are less likely to schedule an operation for patients who have appointment late during the work shift than for patients who have appointment at the beginning of the work shift. Understanding how the quality of medical decisions depends on when the patient is seen is important for achieving both efficiency and fairness in health care, where long shifts are popular.

    The fifth essay, Preferences for Outcome Editing in Monetary and Social Contexts, compares whether individuals use the same rules for mental representation of monetary outcomes (e.g., purchases, expenses) as for social outcomes (e.g., having nice time with friends). Outcome editing is an operation in mental accounting that determines whether individuals prefer to first combine multiple outcomes before their evaluation (integration) or evaluate each outcome separately (segregation). I find that the majority of individuals express different preferences for outcome editing in the monetary context than in the social context. Further, while the results on the editing of monetary outcomes are consistent with theoretical predictions, no existing model can explain the editing of social outcomes.

    List of papers
    1. Fairness versus efficiency: how procedural fairness concerns affect coordination
    Open this publication in new window or tab >>Fairness versus efficiency: how procedural fairness concerns affect coordination
    2017 (English)In: Experimental Economics, ISSN 1386-4157, E-ISSN 1573-6938Article in journal (Refereed) Published
    Abstract [en]

    We investigate in a laboratory experiment whether procedural fairness concerns affect how well individuals are able to solve a coordination problem in a two-player Volunteer’s Dilemma. Subjects receive external action recommendations, either to volunteer or to abstain from it, in order to facilitate coordination and improve efficiency. We manipulate the fairness of the recommendation procedure by varying the probabilities of receiving the disadvantageous recommendation to volunteer between players. We find evidence that while recommendations improve overall efficiency regardless of their implications for expected payoffs, there are behavioural asymmetries depending on the recommendation: advantageous recommendations are followed less frequently than disadvantageous ones and beliefs about others’ actions are more pessimistic in the treatment with recommendations inducing unequal expected payoffs.

    Place, publisher, year, edition, pages
    Springer, 2017
    Keyword
    Coordination, Correlated Equilibrium, Recommendations, Procedural fairness, Volunteer's Dilemma, Experiment
    National Category
    Economics
    Identifiers
    urn:nbn:se:liu:diva-140644 (URN)10.1007/s10683-017-9540-5 (DOI)
    Funder
    Swedish Research Council Formas
    Available from: 2017-09-20 Created: 2017-09-20 Last updated: 2017-11-17Bibliographically approved
  • Public defence: 2017-12-14 13:00 Berzeliussalen, Linköping
    Nord, Anette
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Bystander CPR: New aspects of CPR training among students and the importance of bystander education level on survival2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: It has been proved that bystander cardiopulmonary resuscitation (CPR) saves lives; however, which training method in CPR is most instructive and whether survival is affected by the training level of the bystander have not yet been fully described.

    Aim: To identify the factors that may affect 7th grade students’ acquisition of CPR skills during CPR training and their willingness to act, and to describe 30-day survival from outof- hospital cardiac arrest (OHCA) after bystander CPR and the actions performed by laymen versus off-duty medically educated personnel.

    Methods: Studies I–III investigate a CPR training intervention given to students in 7th grade during 2013–2014. The classes were randomized to the main intervention: the mobile phone application (app) or DVD-based training. Some of the classes were randomized to one or several additional interventions: a practical test with feedback, reflection, a web course, a visit from elite athletes and automated external defibrillator (AED) training. The students’ practical skills, willingness to act and knowledge of stroke symptoms, symptoms of acute myocardial infarction (AMI) and lifestyle factors were assessed directly after training and at 6 months using the Laerdal PC SkillReporting system (and entered into a modified version of the Cardiff test scoring sheet) and a questionnaire. The Cardiff test resulted in a total score of 12–48 points, and the questionnaire resulted in a total score of 0–7 points for stroke symptoms, 0–9 points for symptoms of AMI and 0– 6 points on lifestyle factors. Study IV is based on retrospective data from the national quality register, the Swedish registry of cardiopulmonary resuscitation, 2010-2014.

    Results: A total of 1339 students were included in the CPR training intervention. The DVD-based group was superior to the app-based group in CPR skills, with a total score of 35 (SD 4.o) vs 33 (SD 4.2) points directly after training (p<0.001) and 33 (SD 4.0) vs 31 (SD 4.2) points at six months (p<0.001). Of the additional interventions, the practical test with feedback had the greatest influence regarding practical skills: at six months the intervention group scored 32 (SD 3.9) points and the control group (CPR only) scored 30 (SD 4.0) points (p<0.001). Reflection, the web course, visits from elite athletes and AED training did not further increase the students’ acquisition of practical CPR skills.

    The students who completed the web course Help-Brain-Heart received a higher total score for theoretical knowledge in comparison with the control group, directly after training: stroke 3.8 (SD 1.8) vs 2.7 (SD 2.0) points (p<0.001); AMI 4.0 (SD 2.0) vs 2.5 (SD 2.0) points (p<0.001); lifestyle factors 5.4 (SD 1.2) vs 4.5 (SD 2.0) points p<0.001.

    Most of the students (77% at 6 months), regardless of the intervention applied, expressed that they would perform both chest compressions and ventilations in a cardiac arrest (CA) situation involving a relative. If a stranger had CA, a significantly lower proportion of students (32%; p<0.001) would perform both compressions and ventilations. In this case, however, many would perform compressions only.

    In most cases of bystander-witnessed OHCA, CPR was performed by laymen. Off-duty health care personnel bystanders initiated CPR within 1 minute vs 2 minutes for laymen (p<0.0001). Thirty-day survival was 14.7% among patients who received CPR from laymen and 17.2% (p=0.02) among patients who received bystander CPR from off-duty health care personnel.

    Conclusions: The DVD-based method was superior to the app-based method in terms of teaching practical CPR skills to 7th grade students. Of the additional interventions, a practical test with feedback was the most efficient intervention to increase learning outcome. The additional interventions, reflection, web course, visit from elite athletes and AED did not increase CPR skills further. However, the web course Help-Brain-Heart improved the students’ acquisition of theoretical knowledge regarding stroke, AMI and lifestyle factors. For OHCA, off-duty health care personnel bystanders initiated CPR earlier and 30-day survival was higher compared with laymen bystanders.

    List of papers
    1. Effect of mobile application-based versus DVD-based CPR training on students practical CPR skills and willingness to act: a cluster randomised study
    Open this publication in new window or tab >>Effect of mobile application-based versus DVD-based CPR training on students practical CPR skills and willingness to act: a cluster randomised study
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    2016 (English)In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 6, no 4, e010717- p.Article in journal (Refereed) Published
    Abstract [en]

    Objectives: The aim was to compare students practical cardiopulmonary resuscitation (CPR) skills and willingness to perform bystander CPR, after a 30 min mobile application (app)-based versus a 50 min DVD-based training. Settings: Seventh grade students in two Swedish municipalities. Design: A cluster randomised trial. The classes were randomised to receive app-based or DVD-based training. Willingness to act and practical CPR skills were assessed, directly after training and at 6 months, by using a questionnaire and a PC Skill Reporting System. Data on CPR skills were registered in a modified version of the Cardiff test, where scores were given in 12 different categories, adding up to a total score of 12-48 points. Training and measurements were performed from December 2013 to October 2014. Participants: 63 classes or 1232 seventh grade students (13-year-old) were included in the study. Primary and secondary outcome measures: Primary end point was the total score of the modified Cardiff test. The individual variables of the test and self-reported willingness to make a life-saving intervention were secondary end points. Results: The DVD-based group was superior to the app-based group in CPR skills; a total score of 36 (3338) vs 33 (30-36) directly after training (pamp;lt;0.001) and 33 (30-36) and 31 (28-34) at 6 months (pamp;lt;0.001), respectively. At 6 months, the DVD group performed significantly better in 8 out of 12 CPR skill components. Both groups improved compression depth from baseline to follow-up. If a friend suffered cardiac arrest, 78% (DVD) versus 75% (app) would do compressions and ventilations, whereas only 31% (DVD) versus 32% (app) would perform standard CPR if the victim was a stranger. Conclusions: At 6 months follow-up, the 50 min DVD-based group showed superior CPR skills compared with the 30 min app-based group. The groups did not differ in regard to willingness to make a life-saving effort.

    Place, publisher, year, edition, pages
    BMJ PUBLISHING GROUP, 2016
    National Category
    Other Medical Sciences not elsewhere specified
    Identifiers
    urn:nbn:se:liu:diva-129507 (URN)10.1136/bmjopen-2015-010717 (DOI)000376391400104 ()27130166 (PubMedID)
    Note

    Funding Agencies|Foundation for cardiopulmonary resuscitation in Sweden; Swedish Resuscitation Council; Swedish Heart-Lung Foundation [20130629]; County Council of Ostergotland

    Available from: 2016-06-20 Created: 2016-06-20 Last updated: 2017-10-31
    2. Effect of two additional interventions, test and reflection, added to standard cardiopulmonary resuscitation training on seventh grade students practical skills and willingness to act: a cluster randomised trial
    Open this publication in new window or tab >>Effect of two additional interventions, test and reflection, added to standard cardiopulmonary resuscitation training on seventh grade students practical skills and willingness to act: a cluster randomised trial
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    2017 (English)In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 7, no 6, e014230Article in journal (Refereed) Published
    Abstract [en]

    Objectives The aim of this research is to investigate if two additional interventions, test and reflection, after standard cardiopulmonary resuscitation (CPR) training facilitate learning by comparing 13-year-old students practical skills and willingness to act. Settings Seventh grade students in council schools of two municipalities in south-east Sweden. Design School classes were randomised to CPR training only (O), CPR training with a practical test including feedback (T) or CPR training with reflection and a practical test including feedback (RT). Measures of practical skills and willingness to act in a potential life-threatening situation were studied directly after training and at 6 months using a digital reporting system and a survey. A modified Cardiff test was used to register the practical skills, where scores in each of 12 items resulted in a total score of 12-48 points. The study was conducted in accordance with current European Resuscitation Council guidelines during December 2013 to October 2014. Participants 29 classes for a total of 587 seventh grade students were included in the study. Primary and secondary outcome measures The total score of the modified Cardiff test at 6 months was the primary outcome. Secondary outcomes were the total score directly after training, the 12 individual items of the modified Cardiff test and willingness to act. Results At 6 months, the T and O groups scored 32 (3.9) and 30 (4.0) points, respectively (pamp;lt;0.001), while the RT group scored 32 (4.2) points (not significant when compared with T). There were no significant differences in willingness to act between the groups after 6 months. Conclusions A practical test including feedback directly after training improved the students acquisition of practical CPR skills. Reflection did not increase further CPR skills. At 6-month follow-up, no intervention effect was found regarding willingness to make a life-saving effort.

    Place, publisher, year, edition, pages
    BMJ Publishing Group Ltd, 2017
    National Category
    Other Medical Sciences not elsewhere specified
    Identifiers
    urn:nbn:se:liu:diva-140073 (URN)10.1136/bmjopen-2016-014230 (DOI)000406391200048 ()28645953 (PubMedID)2-s2.0-85021624804 (Scopus ID)
    Note

    Funding Agencies|Foundation for Cardiopulmonary Resuscitation in Sweden; Swedish Resuscitation Council; Swedish Heart-Lung Foundation [20130629]; County Council of Ostergotland

    Available from: 2017-08-28 Created: 2017-08-28 Last updated: 2017-10-31Bibliographically approved
    3. The effect of a national web course "Help-Brain-Heart" as a supplemental learning tool before CPR training: a cluster randomised trial
    Open this publication in new window or tab >>The effect of a national web course "Help-Brain-Heart" as a supplemental learning tool before CPR training: a cluster randomised trial
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    2017 (English)In: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, ISSN 1757-7241, E-ISSN 1757-7241, Vol. 25, 93Article in journal (Refereed) Published
    Abstract [en]

    Background: The effectiveness of cardiopulmonary resuscitation (CPR) learning methods is unclear. Our aim was to evaluate whether a web course before CPR training, teaching the importance of recognition of symptoms of stroke and acute myocardial infarction (AMI) and a healthy lifestyle, could influence not only theoretical knowledge but also practical CPR skills or willingness to act in a cardiac arrest situation. Methods: Classes with 13-year-old students were randomised to CPR training only (control) or a web course plus CPR training (intervention). Data were collected (practical test and a questionnaire) directly after training and at 6 months. CPR skills were evaluated using a modified Cardiff test (12-48 points). Knowledge on stroke symptoms (0-7 points), AMI symptoms (0-9 points) and lifestyle factors (0-6 points), and willingness to act were assessed by the questionnaire. The primary endpoint was CPR skills at 6 months. CPR skills directly after training, willingness to act and theoretical knowledge were secondary endpoints. Training and measurements were performed from December 2013 to October 2014. Results: Four hundred and thirty-two students were included in the analysis of practical skills and self-reported confidence. The mean score for CPR skills was 34 points after training (control, standard deviation [SD] 4.4; intervention, SD 4.0; not significant [NS]); and 32 points at 6 months for controls (SD 3.9) and 33 points for intervention (SD 4.2; NS). At 6 months, 73% (control) versus 80% (intervention; P = 0.05) stated they would do compressions and ventilation if a friend had a cardiac arrest, whereas 31% versus 34% (NS) would perform both if the victim was a stranger. One thousand, two hundred and thirty-two students were included in the analysis of theoretical knowledge; the mean scores at 6 months for the control and intervention groups were 2.8 (SD 1.6) and 3.2 (SD 1.4) points (P amp;lt; 0.001) for stroke symptoms, 2.6 (SD 2.0) and 2.9 (SD 1.9) points (P = 0.008) for AMI symptoms and 3.2 (SD 1.2) and 3.4 (SD 1.0) points (P amp;lt; 0.001) for lifestyle factors, respectively. Discussion: Use of online learning platforms is a fast growing technology that increases the flexibility of learning in terms of location, time and is available before and after practical training. Conclusions: A web course before CPR training did not influence practical CPR skills or willingness to act, but improved the students theoretical knowledge of AMI, stroke and lifestyle factors.

    Place, publisher, year, edition, pages
    BIOMED CENTRAL LTD, 2017
    Keyword
    CPR training; Web course; Willingness; Infarction; Stroke; Lifestyle factors; Students
    National Category
    Other Medical Sciences not elsewhere specified
    Identifiers
    urn:nbn:se:liu:diva-141119 (URN)10.1186/s13049-017-0439-0 (DOI)000410326900001 ()28899418 (PubMedID)
    Note

    Funding Agencies|Foundation for Cardiopulmonary Resuscitation in Sweden; Swedish Resuscitation Council; Swedish Heart-Lung Foundation [20130629]; County Council of Ostergotland

    Available from: 2017-09-27 Created: 2017-09-27 Last updated: 2017-10-31
    4. Increased survival from out-of-hospital cardiac arrest when off duty medically educated personnel perform CPR compared with laymen.
    Open this publication in new window or tab >>Increased survival from out-of-hospital cardiac arrest when off duty medically educated personnel perform CPR compared with laymen.