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  • 1.
    Lindström, Stefan B
    et al.
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Thore, Carl-Johan
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    10000 mechanics problems at the press of a button2015In: Proceedings of Svenska Mekanikdagar, Linköping University, 2015, p. 84-Conference paper (Other academic)
    Abstract [en]

    Problem solving is at the heart of the mechanics curriculum, and developing problem solving skills is an important learning objective in basic and advanced mechanics courses at the undergraduate level. In alignment with this tradition, written examinations are mainly designed to test problem solving capabilities. Despite the fact that students spend most of their mechanics studies solving mechanics problems, an alarming fraction of them fail the written examination. One possible explanation is that a problem solving infrastructure, e.g. answers to problems and opportunities for collaboration with fellow students, is provided during the study period of courses, but missing during the examination.

  • 2.
    Nilsson, Sara
    et al.
    Linköping University, Department of Management and Engineering, Manufacturing Engineering. Linköping University, Faculty of Science & Engineering.
    Jensen, Jonas
    Linköping University.
    Björkman, Mats
    Linköping University, Department of Management and Engineering, Manufacturing Engineering. Linköping University, Faculty of Science & Engineering.
    Sundin, Erik
    Linköping University, Department of Management and Engineering, Manufacturing Engineering. Linköping University, Faculty of Science & Engineering.
    11 Rules of Design for Manufacturing when Producing Pre-Impregnated Carbon Fiber-Reinforced Plastic Components: an Application at SAAB Aerostructures2016In: SAE Technical Papers, Society of Automotive Engineers, 2016, p. 1-8, article id 2016-01-2124Conference paper (Refereed)
    Abstract [en]

    Carbon ber-reinforced plastic (CFRP) is one of the most commonly used materials in the aerospace industry today. CFRP in pre- impregnated form is an anisotropic material whose properties can be controlled to a high level by the designer. Sometimes, these properties make the material hard to predict with regards to how the geometry affects manufacturing aspects. This paper describes eleven design rules originating from different guidelines that describe geometrical design choices and deals with manufacturability problems that are connected to them, why they are connected and how they can be minimized or avoided. Examples of design choices dealt with in the rules include double curvature shapes, assembly of uncured CFRP components and access for non-destructive testing (NDT). To verify the technical content and ensure practicability, the rules were developed by, inter alia, studying literature and performing case studies at SAAB Aerostructures. The research was done through a collaboration between Linköping University and SAAB Aerostructures in a state-funded project. This ensured a balanced approach between academic advancement and usefulness in commercial projects. 

  • 3.
    Berkesand, Peter
    Linköping University, Department for Studies of Social Change and Culture. Linköping University, Faculty of Arts and Sciences.
    115 orsaker att dö. Sjukdomshistoria för hembygdsforskare2000In: Bygd och natur : tidskrift för hembygdsvård, ISSN 0345-7982, no 4, p. 4-7Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Sedan urminnes tider har mänskligheten drabbats av farsoter som orsakat lidande och till sist död. De sjukdomar vi idag enkelt botar med penicillin var dödliga för bara drygt ett halvt sekel sedan. Infektionssjukdomar orsakde de flesta dödsfallen. Dödsorsaker var något som måste anges i dödsattesten. År 1860 hade Sverige 115 olika dödsorsaker och 30 år senare fanns det 302. Vi hade inte blivit sjukare utan vetenskapen hade upptäckt att baktierier orsakade många av de vanligaste infektionssjukdomarna.

    Artikeln listar några av de vanligaste sjukdomarna i vårt land under 1700- till 1900-talet och antalet avlidna i de olika farsoterna. Medicinalverkets klassifiaktionssystem behandlas samt källor och statistik.

    Ur dödsorsakerna finns det mycket information att hämta. De visar levnadsförhållandena i ett samhälle och samhällets status som kan mätas i till exempel spädbarnsdödligheten. Ju lägre spädbarnsdödlighet desto bättre välstånd anses landet ha. Genom dödsorsakerna kan man också kartlägga och följa epidemier som grasserat i vårt land. Även lokal sjukdomsspridning som begränsat sig till ett visst eller vissa områden, så kallade endemier, går att följa.

  • 4.
    Holmbom, Martin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Urology in Östergötland.
    Giske, Christian G.
    Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden.; Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden..
    Fredrikson, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Östholm Balkhed, Åse
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Infectious Diseases.
    Claesson, Carina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nilsson, Lennart E
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Hoffmann, Mikael
    Linköping University, Department of Medical and Health Sciences, Division of Health Care Analysis. Linköping University, Faculty of Medicine and Health Sciences.
    Hanberger, Håkan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Infectious Diseases.
    14-Year Survey in a Swedish County Reveals a Pronounced Increase in Bloodstream Infections (BSI). Comorbidity: An Independent Risk Factor for Both BSI and Mortality2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 11Article in journal (Refereed)
    Abstract [en]

    Objectives: we assessed the incidence, risk factors and outcome of BSI over a 14-year period (2000-2013) in a Swedish county.

    Methods: retrospective cohort study on culture confirmed BSI among patients in the county of Östergötland, Sweden, with approximately 440,000 inhabitants. A BSI was defined as either community-onset BSI (CO-BSI) or hospital-acquired BSI (HA-BSI).

    Results: of a total of 11,480 BSIs, 67% were CO-BSI and 33% HA-BSI. The incidence of BSI increased by 64% from 945 to 1,546 per 100,000 hospital admissions per year during the study period. The most prominent increase, 83% was observed within the CO-BSI cohort whilst HA-BSI increased by 32%. Prescriptions of antibiotics in outpatient care decreased with 24% from 422 to 322 prescriptions dispensed/1,000 inhabitants/year, whereas antibiotics prescribed in hospital increased by 67% (from 424 to 709 DDD per 1,000 days of care). The overall 30-day mortality for HA-BSIs was 17.2%, compared to 10.6% for CO-BSIs, with an average yearly increase per 100,000 hospital admissions of 2 and 5% respectively. The proportion of patients with one or more comorbidities, increased from 20.8 to 55.3%. In multivariate analyses, risk factors for mortality within 30 days were: HA-BSI (2.22); two or more comorbidities (1.89); single comorbidity (1.56); CO-BSI (1.21); male (1.05); and high age (1.04).

    Conclusion: this survey revealed an alarming increase in the incidence of BSI over the 14-year study period. Interventions to decrease BSI in general should be considered together with robust antibiotic stewardship programmes to avoid both over- and underuse of antibiotics.

  • 5.
    Nilsson, Line
    et al.
    Aarhus University, Denmark.
    Palm, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Uppsala University, Sweden.
    Norregaard, Rikke
    Aarhus University, Denmark.
    15-Deoxy-Delta(12,14)-prostaglandin J(2) Exerts Antioxidant Effects While Exacerbating Inflammation in Mice Subjected to Ureteral Obstruction2017In: Mediators of Inflammation, ISSN 0962-9351, E-ISSN 1466-1861, article id 3924912Article in journal (Refereed)
    Abstract [en]

    Urinary obstruction is associated with inflammation and oxidative stress, leading to renal dysfunction. Previous studies have shown that 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) has both antioxidant and anti-inflammatory effects. Using a unilateral ureteral obstruction (UUO) mouse model, we examined the effects of 15d-PGJ(2) on oxidative stress and inflammation in the kidney. Mice were subjected to UUO for 3 days and treated with 15d-PGJ(2). Protein and RNA expression were examined using immunoblotting and qPCR. 15d-PGJ(2) increased NF-E2-related nuclear factor erythroid-2 (Nrf2) protein expression in response to UUO, and heme oxygenase 1 (HO-1), a downstream target of Nrf2, was induced by 15d-PGJ(2). Additionally, 15d-PGJ(2) prevented protein carbonylation, a UUO-induced oxidative stress marker. Inflammation, measured by nuclear NF-kappa B, F4/80, and MCP-1, was increased in response to UUO and further increased by 15d-PGJ(2). Renal injury was aggravated by 15d-PGJ(2) treatment as measured by kidney injury molecule-1 (KIM-1) and cortical caspase 3 content. No effect of 15d-PGJ(2) was observed on renal function in mice subjected to UUO. This study illustrates differentiated functioning of 15d-PGJ(2) on inflammation and oxidative stress in response to obstructive nephropathy. High concentrations of 15d-PGJ(2) protects against oxidative stress during 3-day UUO in mice; however, it aggravates the associated inflammation.

  • 6.
    Browaldh, Nanna
    et al.
    Karolinska University Hospital.
    Friberg, Danielle
    Karolinska University Hospital.
    Svanborg, Eva
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Neurophysiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurophysiology UHL.
    Nerfeldt, Pia
    Karolinska University Hospital.
    15-year efficacy of uvulopalatopharyngoplasty based on objective and subjective data2011In: Acta Oto-Laryngologica, ISSN 0001-6489, E-ISSN 1651-2251, Vol. 131, no 12, p. 1303-1310Article in journal (Refereed)
    Abstract [en]

    Conclusions: This follow-up showed a stable and significant decrease in median oxygen desaturation index 4% (ODI(4)) values over the years. Approximately two-thirds of the patients fulfilled the success criteria (ODI4 reduction of 50% and andlt;20) after 15 years. A majority had improved/cured excessive daytime sleepiness (EDS) and were satisfied. No increased mortality rate was seen. Objectives: To evaluate sleep apnoea recordings and symptoms in patients with obstructive sleep apnoea syndrome 15 years after uvulopalatopharyngoplasty (UPPP) compared to baseline and previous follow-ups. Methods: This was a non-randomized, prospective intervention study on 50 patients who underwent UPPP during 1985-88. Their initial median age was 49 years (range 38-71) and ODI4 was 26.5 (4-82). Results: In all, 13 patients had died; 26 patients underwent sleep apnoea recordings. Median ODI4 had decreased from 26.5 (range 4-82) to 8.5 (0-60), p andlt; 0.01, a mean reduction of 52%; 65% of patients achieved the success criteria. One-third was objectively categorized as non-snorers. Median body mass index was unchanged. The questionnaires were answered by 32 of 37 patients; 88% reported improved or cured EDS and 78% were satisfied. Pharyngeal disturbances ratings were low. The standardized mortality rate did not differ from the general Swedish population.

  • 7.
    Sivik, Tove
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Oncology. Linköping University, Faculty of Health Sciences.
    Gunnarsson, Cecilia
    Linköping University, Department of Clinical and Experimental Medicine, Medical Genetics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pathology and Clinical Genetics.
    Fornander, Tommy
    Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.
    Nordenskjöld, Bo
    Linköping University, Department of Clinical and Experimental Medicine, Oncology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Skoog, Lambert
    Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.
    Stål, Olle
    Linköping University, Department of Clinical and Experimental Medicine, Oncology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Jansson, Agneta
    Linköping University, Department of Clinical and Experimental Medicine, Oncology. Linköping University, Faculty of Health Sciences.
    17β-hydroxysteroid dehydrogenase type 14 is a predictive marker for tamoxifen response in oestrogen receptor positive breast cancer2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 7, p. e40568-Article in journal (Refereed)
    Abstract [en]

    Introduction: 17β-hydroxysteroid dehydrogenases (17βHSDs) are important enzymes regulating the pool of bioactive steroids in the breast. The current study was undertaken in order to evaluate implications of 17βHSD14 in breast cancer, measuring 17βHSD14 protein expression in breast tumours.

    Methods: An antibody targeting the 17βHSD14 antigen was generated and validated using HSD17B14-transfected cells and a peptide-neutralising assay. Tissue microarrays with tumours from 912 post-menopausal women diagnosed with lymph node-negative breast cancer, and randomised to adjuvant tamoxifen or no endocrine treatment, were analysed for 17βHSD14 protein expression with immunohistochemistry.

    Results: Results were obtained from 847 tumours. Patients with oestrogen positive tumours with high 17βHSD14 expression had fewer local recurrences when treated with tamoxifen (HR 0.38; 95% C.I. 0.19–0.77, p = 0.007) compared to patients with lower tumoural 17βHSD14 expression, for whom tamoxifen did not reduce the number of local recurrences (HR 1.19; 95% C.I. 0.54–2.59; p = 0.66). No prognostic importance of 17βHSD14 was seen for systemically untreated patients.

    Conclusions: Using a highly specific validated antibody for immunohistochemical analysis of a large number of breast tumours, we have shown that tumoural expression levels of 17βHSD14 can predict the outcome of adjuvant tamoxifen treatment in terms of local recurrence-free survival in patients with lymph node-negative ER+ breast cancer. The results need be verified to confirm any clinical relevance.

  • 8.
    Bjurström, Erling
    Linköping University, Department for Studies of Social Change and Culture, Department of Culture Studies. Linköping University, Faculty of Arts and Sciences.
    1968 som minnespolitik2012In: Aktuel forskning ved Institut for Litteratur, Kultur og Medier, ISSN 1903-5705, p. 1-11Article in journal (Other academic)
    Abstract [sv]

    1968 är ett mytomspunnet år. Håller man sig till 1900-talet är det få årtal som kan konkurrera med 1968 i fråga om symbolisk laddning och dragningskraft. Denna dragningskraft utövar det även på omkringliggande årtal: i dag står 1968 mer för en epok än ett årtal. När denna epok börjar och slutar är oklart, men att den kulminerade 1968 råder det, så vitt jag kan bedöma, stor enighet om. 1968 betraktas allmänt som kulmen på en våg av ungdomsprotester, kravaller, mobilisering, livsstilsexperiment, en politisk vänstervåg, galna upptåg och framväxten av ett specifikt generationsmedvetande. Det är framför allt som generationsmarkör 1968 har skrivit in sig i historien

  • 9.
    Jaarsma, Tiny
    et al.
    Linköping University, Department of Social and Welfare Studies, Division of Health, Activity and Care. Linköping University, Faculty of Arts and Sciences.
    Strömberg, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    20 Things You Didn't Know About European Cardiac Nurses2014In: Journal of Cardiovascular Nursing, ISSN 0889-4655, E-ISSN 1550-5049, Vol. 29, no 4, p. 291-292Article in journal (Other academic)
  • 10.
    Jaarsma, Tiny
    et al.
    Linköping University, Department of Social and Welfare Studies, Division of Health, Activity and Care. Linköping University, Faculty of Arts and Sciences.
    Steinke, Elaine
    Wichita State University, KS, USA .
    20 Things You Didnt Know About Sex and Heart Disease2014In: Journal of Cardiovascular Nursing, ISSN 0889-4655, E-ISSN 1550-5049, Vol. 29, no 3, p. 207-208Article in journal (Other academic)
  • 11.
    Jantunen, Liisa
    et al.
    Environment Canada, Canada.
    Wong, Fiona
    Stockholm University.
    Gawor, Anya
    Environment Canada.
    Kylin, Henrik
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Helm, Paul
    Ontario Ministry of the Environment, Canada.
    Stern, Gary
    University of Manitoba, Canada.
    Strachan, William
    Environment Canada, Canada.
    Burniston, Deborah
    Environment Canada, Canada.
    Bidleman, Terry
    Umeå University.
    20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 23, p. 13844-13852Article in journal (Refereed)
    Abstract [en]

    The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air−water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water−air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air−surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

  • 12.
    Bergh, Torsten
    et al.
    Swedish Transport Adm, Sweden; Movea Trafikkonsult, Sweden.
    Remgard, Mats
    Swedish Transport Adm, Sweden.
    Carlsson, Arne
    Swedish National Rd and Transport Research Institute, Linköping, Sweden.
    Olstam, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Swedish National Road and Transport Research Institute, Linköping, Sweden.
    Strömgren, Per
    Movea Trafikkonsult, Sweden.
    2+1-roads Recent Swedish Capacity and Level-of-Service Experience2016In: INTERNATIONAL SYMPOSIUM ON ENHANCING HIGHWAY PERFORMANCE (ISEHP), (7TH INTERNATIONAL SYMPOSIUM ON HIGHWAY CAPACITY AND QUALITY OF SERVICE, 3RD INTERNATIONAL SYMPOSIUM ON FREEWAY AND TOLLWAY OPERATIONS), ELSEVIER SCIENCE BV , 2016, Vol. 15, p. 331-345Conference paper (Refereed)
    Abstract [en]

    The first Swedish 2+1 median barrier road was opened in 1998. The concept was to retrofit the standard existing two-lane 13 m paved width cross-section at 90 and 110 kph posted speed limit without widening. This design has one continuous lane in each direction, a middle lane changing direction every one to three kilometres with a median barrier separating the two traffic directions. Today over 2 700 km 2+1 median barrier roads are opened for traffic. AADTs vary from some 3 000 to 20 000 with an average just below 10 000 nowadays normally with 100 kph. The concept has lately been enhanced also to cover the existing 9 m paved width cross-section. The design concept is the same from a drivers viewpoint, one continuous lane in each direction with a middle lane changing direction and a separating median barrier. This is created by introducing a continuous median barrier and adding overtaking lanes within an overtaking strategy. The differences are the existence of 1+1-sections, less overtaking opportunities and a slightly more narrow cross-section. Some 15 projects are opened. The purpose of this paper is to summarize present knowledge on level-of-service issues as they are presented in Swedish design and assessment guidelines and to give an overview of field measurements and theoretical analytical and simulation studies supporting the recommendations.

  • 13.
    Hallert, Eva
    et al.
    Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Rehabilitation Center. Linköping University, Department of Medical and Health Sciences, Health Technology Assessment and Health Economics.
    Husberg, Magnus
    Linköping University, Department of Medical and Health Sciences, Health Technology Assessment and Health Economics. Linköping University, Faculty of Health Sciences.
    Skogh, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Rheumatology.
    28-joint count disease activity score at 3 months after diagnosis of early rheumatoid arthritis is strongly associated with direct and indirect costs over the following 4 years: the Swedish TIRA project2011In: Rheumatology, ISSN 1462-0324, E-ISSN 1462-0332, Vol. 50, no 7, p. 1259-1267Article in journal (Refereed)
    Abstract [en]

    Methods. Three-hundred and twenty patients with early (1 year) RA were assessed at regular intervals. Clinical and laboratory data were collected and patients reported health-care utilization and number of days lost from work. At 3-month follow-up, patients were divided into two groups according to disease activity, using DAS-28 with a cut-off level at 3.2. Direct and indirect costs and EuroQol-5D over the following 4 years were compared between the groups. Multivariate regression models were used to control for possible covariates. Results. Three months after diagnosis, a DAS-28 level of epsilon 3.2 was associated with high direct and indirect costs over the following 4 years. Patients with DAS-28 epsilon 3.2 at 3-month follow-up had more visits to physician, physiotherapist, occupational therapist and nurse, higher drug costs, more days in hospital and more extensive surgery compared with patients with 3-month DAS-28 less than 3.2. Number of days lost from work due to sick leave and permanent work disability was also higher in this group. The effect of disease activity on health-related quality of life was highly significant. In regression models, DAS-28 at 3-month follow-up was significantly associated with costs over the following years. Conclusions. Three months after diagnosis, DAS-28 is an important prognostic marker regarding health-care utilization and costs. Achieving remission or low disease activity 3 months after diagnosis is likely to decrease morbidity, increase quality of life and save costs for the patient and for society over the following years.

  • 14.
    Vrotsou, Katerina
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Forsell, Camilla
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    2D and 3D Representations for Feature Recognition in Time Geographical Diary Data2010In: Information Visualization, ISSN 1473-8716, E-ISSN 1473-8724, Vol. 9, no 4, p. 263-276Article in journal (Refereed)
    Abstract [en]

    Time geographical representations are becoming a common approach to analysing spatio-temporal data. Such representations appear intuitive in the process of identifying patterns and features as paths of populations form tracks through the 3D space, which can be seen converging and diverging over time. In this article, we compare 2D and 3D representations within a time geographical visual analysis tool for activity diary data. We identify a representative task and evaluate task performance between the two representations. The results show that the 3D representation has benefits over the 2D representation for feature identification but also indicate that these benefits can be lost if the 3D representation is not carefully constructed to help the user to see them.

  • 15.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Li, Xun
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jacobson, Henrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Andersson, Sven
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Boulle, Alexandre
    CNRS UMR 7315, Centre Européen de la Céramique, Limoges Cedex, France.
    Chaussende, Didier
    LMGP, CNRS UMR 5628, Grenoble, France.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    3C-SiC Heteroepitaxy on Hexagonal SiC Substrates2013In: Silicon Carbide and Related Materials 2012 / [ed] Alexander A. Lebedev, Sergey Yu. Davydov, Pavel A. Ivanov and Mikhail E. Levinshtein, Trans Tech Publications , 2013, Vol. 740-742, p. 257-262Conference paper (Refereed)
    Abstract [en]

    The growth of 3C-SiC on hexagonal polytype is addressed and a brief review is given for various growth techniques. The Chemical Vapor Deposition is shown as a suitable technique to grow single domain 3C epilayers on 4H-SiC substrate and a 12.5 µm thick layer is demonstrated; even thicker layers have been obtained. Various characterization techniques including optical microscopy, X-ray techniques and photoluminescence are compared for the evaluation of the crystal quality and purity of the layers.

  • 16.
    Ong, Jeb A.
    et al.
    Maisonneuve Rosemt Hospital, Canada; University of Montreal, Canada.
    Auvinet, Edouard
    University of Montreal, Canada.
    Forget, Karolyn J.
    Maisonneuve Rosemt Hospital, Canada.
    Lagali, Neil
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Ophthalmology in Linköping.
    Fagerholm, Per
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Ophthalmology in Linköping.
    Griffith, May
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Maisonneuve Rosemt Hospital, Canada.
    Meunier, Jean
    University of Montreal, Canada; University of Montreal, Canada.
    Brunette, Isabelle
    Maisonneuve Rosemt Hospital, Canada; University of Montreal, Canada.
    3D Corneal Shape After Implantation of a Biosynthetic Corneal Stromal Substitute2016In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 57, no 6, p. 2355-2365Article in journal (Refereed)
    Abstract [en]

    PURPOSE. The current and projected shortage of transplantable human donor corneas has prompted the development of long-term alternatives to human donor tissue for corneal replacement. The biosynthetic stromal substitutes (BSS) characterized herein represent a potentially safe alternative to donor organ transplantation for anterior corneal stromal diseases. The goal of this phase 1 safety study was to characterize the three-dimensional (3D) corneal shape of the first 10 human patients implanted with a BSS and assess its stability over time. METHODS. Ten patients underwent anterior lamellar keratoplasty using a biosynthetic corneal stromal implant for either advanced keratoconus or central corneal scarring. Surgeries were performed at Linkoping University Hospital, between October and November 2007. Serial corneal topographies were performed on all eyes up to a 4-year follow-up when possible. Three-dimensional shape average maps were constructed for the 10 BSS corneas and for 10 healthy controls. Average 3D shape corneal elevation maps, difference maps, and statistics maps were generated. RESULTS. The biosynthetic stromal substitutes implants remained stably integrated into the host corneas over the 4-year follow-up period, without signs of wound dehiscence or implant extrusion. The biosynthetic stromal substitutes corneas showed steeper surface curvatures and were more irregular than the healthy controls. CONCLUSIONS. Corneal astigmatism and surface steepness were observed 4 years after BSS implantation, while the implants remained stably integrated in the host corneas. Future studies will indicate if biomaterials technology will allow for the optimization of postoperative surface irregularity after anterior stromal replacement, a new window of opportunity that is not available with traditional corneal transplantation techniques.

  • 17.
    Magnusson, Maria
    et al.
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dahlqvist Leinhard, Olof
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Brynolfsson, Patrik
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Thyr, Per
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    3D Magnetic Resonance Imaging of the Human Brain - Novel Radial Sampling, Filtering and Reconstruction2010In: Proc of the 12th IASTED International Conference on Signal and Image Processing (SIP 2010), August 23 - 25, 2010, Lahaina, Maui, USA / [ed] B. Flinchbaugh, Calgary, AB, Canada: ACTA Press, 2010, p. Track: 710-042-(8 pages)Conference paper (Refereed)
    Abstract [en]

    We have suggested a novel method PRESTO-CAN including radial sampling, filtering and reconstruction of k-space data for 3D-plus-time resolved MRI. The angular increment of the profiles was based on the golden ratio, but the number of angular positions N was locked to be a prime number which guaranteed fix angle positions.The time resolution increased dramatically when the pro-files were partly removed from the k-space using the hourglass filter.We aim for utilizing the MRI-data for fMRI, where the echo times are long, TE ≈ 37-40 ms. This will result in field inhomogeneities and phase variations in the reconstructed images. Therefore, a new calibration and correction procedure was developed. We show that we are able to reconstruct images of the human brain with an image quality in line with what can be obtained by conventional Cartesian sampling.The pulse sequence for PRESTO-CAN was implemented by modifying an existing PRESTO sequence for Cartesian sampling. The effort involved was relatively small and a great advantage will be that we are able to use standard procedures for speeding up data acquisition, i.e. parallel imaging with SENSE.

  • 18. Comina, German
    et al.
    Suska, Anke
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, Faculty of Science & Engineering.
    Filippini, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, Faculty of Science & Engineering.
    3D Printed Unibody Lab-on-a-Chip: Features Survey and Check-Valves Integration dagger2015In: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 6, no 4, p. 437-451Article in journal (Refereed)
    Abstract [en]

    The unibody lab-on-a-chip (ULOC) concept entails a fast and affordable micro-prototyping system built around a single monolithic 3D printed element (unibody). A consumer-grade stereo lithography (SL) 3D printer can configure ULOCs with different forms of sample delivery, transport, handling and readout, while minimizing material costs and fabrication time. ULOC centralizes all complex fabrication procedures and replaces the need for clean room resources, delivering prototypes for less than 1 US$, which can be printed in 10 min and ready for testing in less than 30 min. Recent examples of ULOC integration of transport, chemical sensing for optical readout and flow mixing capabilities are discussed, as well as the integration of the first check-valves for ULOC devices. ULOC valves are strictly unidirectional up to 100 psi, show an exponential forward flow behavior up to 70 psi and can be entirely fabricated with the ULOC approach.

  • 19.
    Östlund, Martin
    et al.
    Linnaeus University, Kalmar.
    Dahlbäck, Nils
    Linköping University, Department of Computer and Information Science, NLPLAB - Natural Language Processing Laboratory. Linköping University, Faculty of Arts and Sciences.
    Petersson, Göran Ingemar
    Linnaeus University, Kalmar.
    3D Visualization as a Communicative Aid in Pharmaceutical Advice-Giving over Distance2011In: Journal of Medical Internet Research, ISSN 1438-8871, E-ISSN 1438-8871, Vol. 13, no 3Article in journal (Refereed)
    Abstract [en]

    Background: Medication misuse results in considerable problems for both patient and society. It is a complex problem with many contributing factors, including timely access to product information. less thanbrgreater than less thanbrgreater thanObjective: To investigate the value of 3-dimensional (3D) visualization paired with video conferencing as a tool for pharmaceutical advice over distance in terms of accessibility and ease of use for the advice seeker. less thanbrgreater than less thanbrgreater thanMethods: We created a Web-based communication service called AssistancePlus that allows an advisor to demonstrate the physical handling of a complex pharmaceutical product to an advice seeker with the aid of 3D visualization and audio/video conferencing. AssistancePlus was tested in 2 separate user studies performed in a usability lab, under realistic settings and emulating a real usage situation. In the first study, 10 pharmacy students were assisted by 2 advisors from the Swedish National Co-operation of Pharmacies call centre on the use of an asthma inhaler. The student-advisor interview sessions were filmed on video to qualitatively explore their experience of giving and receiving advice with the aid of 3D visualization. In the second study, 3 advisors from the same call centre instructed 23 participants recruited from the general public on the use of 2 products: (1) an insulin injection pen, and (2) a growth hormone injection syringe. First, participants received advice on one product in an audio-recorded telephone call and for the other product in a video-recorded AssistancePlus session (product order balanced). In conjunction with the AssistancePlus session, participants answered a questionnaire regarding accessibility, perceived expressiveness, and general usefulness of 3D visualization for advice-giving over distance compared with the telephone and were given a short interview focusing on their experience of the 3D features. less thanbrgreater than less thanbrgreater thanResults: In both studies, participants found the AssistancePlus service helpful in providing clear and exact instructions. In the second study, directly comparing AssistancePlus and the telephone, AssistancePlus was judged positively for ease of communication (P = .001), personal contact (P = .001), explanatory power (P andlt;.001), and efficiency (P andlt;.001). Participants in both studies said that they would welcome this type of service as an alternative to the telephone and to face-to-face interaction when a physical meeting is not possible or not convenient. However, although AssistancePlus was considered as easy to use as the telephone, they would choose AssistancePlus over the telephone only when the complexity of the question demanded the higher level of expressiveness it offers. For simpler questions, a simpler service was preferred. less thanbrgreater than less thanbrgreater thanConclusions: 3D visualization paired with video conferencing can be useful for advice-giving over distance, specifically for issues that require a higher level of communicative expressiveness than the telephone can offer. 3D-supported advice-giving can increase the range of issues that can be handled over distance and thus improve access to product information.

  • 20.
    Khikhlovskyi, Vsevolod
    et al.
    Eindhoven University of Technology, Netherlands; TNO, Netherlands.
    van Breemen, Albert J. J. M.
    Holst Centre, TNO-The Dutch Organization for Applied Scientific Research, The Netherlands.
    Michels, Jasper J.
    Max Planck Institute for Polymer Research (MPI), Germany.
    Janssen, Rene A. J.
    Department of Applied Physics, Eindhoven University of Technology, The Netherlands.
    Gelinck, Gerwin H.
    Department of Applied Physics, Eindhoven University of Technology, The Netherlands; Holst Centre, TNO-The Dutch Organization for Applied Scientific Research, The Netherlands.
    Kemerink, Martijn
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, The Institute of Technology. Department of Applied Physics, Eindhoven University of Technology, The Netherlands.
    3D-Morphology Reconstruction of Nanoscale Phase-Separation in Polymer Memory Blends2015In: Journal of Polymer Science Part B: Polymer Physics, ISSN 0887-6266, E-ISSN 1099-0488, Vol. 53, no 17, p. 1231-1237Article in journal (Refereed)
    Abstract [en]

    In many organic electronic devices functionality is achieved by blending two or more materials, typically polymers or molecules, with distinctly different optical or electrical properties in a single film. The local scale morphology of such blends is vital for the device performance. Here, a simple approach to study the full 3D morphology of phase-separated blends, taking advantage of the possibility to selectively dissolve the different components is introduced. This method is applied in combination with AFM to investigate a blend of a semiconducting and ferroelectric polymer typically used as active layer in organic ferroelectric resistive switches. It is found that the blend consists of a ferroelectric matrix with three types of embedded semiconductor domains and a thin wetting layer at the bottom electrode. Statistical analysis of the obtained images excludes the presence of a fourth type of domains. The criteria for the applicability of the presented technique are discussed. (c) 2015 Wiley Periodicals, Inc.

  • 21.
    Backman, Stina
    et al.
    Linköping University, Department of Thematic Studies, The Department of Gender Studies. Linköping University, Faculty of Arts and Sciences.
    Lundberg, Anna
    Linköping University, Department of Thematic Studies, The Department of Gender Studies. Linköping University, Faculty of Arts and Sciences.
    40+ äntligen tid för lite spinning! En pilotstudie om vardagsmotionsvanor bland svenska kvinnor i medelåldern2013In: On the Move: ACSIS conference 11–13 June Norrköping, Sweden 2013: I rörelse: ACSIS kulturforskningskonferens 11-13 juni Norrköping, Sverige 2013 / [ed] Johanna Dahlin och Tove Andersson, Linköping: Linköping University Electronic Press, 2013, p. 9-14Conference paper (Refereed)
    Abstract [sv]

    Den här presentationen bygger på en pilotstudie om medelålders kvinnor och idrott genomförd under våren 2013. Studien är utformad mot bakgrund av statistiska centralbyråns, SCBs material samlat inom ramen för ULF, undersökningar av levnadsförhållanden. Databasen ULF innehåller statistisk information om hur levnadsförhållanden i Sverige ser ut bland olika grupper. Områden som behandlas i är bland annat boende, ekonomi, hälsa, fritid, sociala relationer, sysselsättning och trygghet. Uppgifterna som publiceras i samlas in genom telefonintervjuer med ett urval av Sveriges befolkning över 16 år.

  • 22.
    Markwardt, Niklas
    et al.
    Laser-Forschungslabor, LIFE-Zentrum, Klinikum der Universität München, Munich, Germany.
    Haj-Hosseini, Neda
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, Faculty of Science & Engineering.
    Hollnburger, Bastian
    Laser-Forschungslabor, LIFE-Zentrum, Klinikum der Universität München, Munich, Germany.
    Stepp, Herbert
    Laser-Forschungslabor, LIFE-Zentrum, Klinikum der Universität München, Munich, Germany.
    Zelenkov, Petr
    Burdenko Neurosurgery Institute, Moscow, Russia.
    Rühm, Adrian
    Laser-Forschungslabor, LIFE-Zentrum, Klinikum der Universität München, Munich, Germany.
    405 nm versus 633 nm for protoporphyrin IX excitation in fluorescence-guided stereotactic biopsy of brain tumors2016In: Journal of Biophotonics, ISSN 1864-063X, E-ISSN 1864-0648, Vol. 9, no 9, p. 901-912Article in journal (Refereed)
    Abstract [en]

    Fluorescence diagnosis may be used to improve the safety and reliability of stereotactic brain tumor biopsies using biopsy needles with integrated fiber optics. Based on 5-aminolevulinic-acid-induced protoporphyrin IX (PpIX) fluorescence, vital tumor tissue can be localized in vivo during the excision procedure to reduce the number of necessary samples for a reliable diagnosis. In this study, the practical suitability of two different PpIX excitation wavelengths (405 nm, 633 nm) was investigated on optical phantoms. Violet excitation at 405 nm provides a 50-fold higher sensitivity for the bulk tumor; this factor increases up to 100 with decreasing fluorescent volume as shown by ray tracing simulations. Red excitation at 633 nm, however, is noticeably superior with regard to blood layers obscuring the fluorescence. Experimental results on the signal attenuation through blood layers of well-defined thicknesses could be confirmed by ray tracing simulations. Typical interstitial fiber probe measurements were mimicked on agarose-gel phantoms. Even in direct contact, blood layers of 20-40 µm between probe and tissue must be expected, obscuring 405-nm-excited PpIX fluorescence almost completely, but reducing the 633-nm-excited signal only by 25.5%. Thus, 633 nm seems to be the wavelength of choice for PpIX-assisted detection of high-grade gliomas in stereotactic biopsy. PpIX signal attenuation through clinically relevant blood layers for 405 nm (violet) and 633 nm (red) excitation.

  • 23.
    Dyverfeldt, Petter
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Bissell, Malenka
    University of Oxford, England.
    Barker, Alex J.
    Northwestern University, IL 60611 USA.
    Bolger, Ann F
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. University of Calif San Francisco, CA USA.
    Carlhäll, Carljohan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Francios, Christopher J.
    University of Wisconsin, WI 53706 USA.
    Frydrychowicz, Alex
    University Hospital Schleswig Holstein, Germany.
    Geiger, Julia
    University of Childrens Hospital Zurich, Switzerland.
    Giese, Daniel
    University Hospital Cologne, Germany.
    Hope, Michael D.
    University of Calif San Francisco, CA USA.
    Kilner, Philip J.
    University of London Imperial Coll Science Technology and Med, England.
    Kozerke, Sebastian
    University of Zurich, Switzerland; ETH, Switzerland.
    Myerson, Saul
    University of Oxford, England.
    Neubauer, Stefan
    University of Oxford, England.
    Wieben, Oliver
    University of Wisconsin, WI 53706 USA.
    Markl, Michael
    Northwestern University, IL 60611 USA; Northwestern University, IL 60611 USA.
    4D flow cardiovascular magnetic resonance consensus statement2015In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 17, no 72Article, review/survey (Refereed)
    Abstract [en]

    Pulsatile blood flow through the cavities of the heart and great vessels is time-varying and multidirectional. Access to all regions, phases and directions of cardiovascular flows has formerly been limited. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has enabled more comprehensive access to such flows, with typical spatial resolution of 1.5x1.5x1.5 - 3x3x3 mm(3), typical temporal resolution of 30-40 ms, and acquisition times in the order of 5 to 25 min. This consensus paper is the work of physicists, physicians and biomedical engineers, active in the development and implementation of 4D Flow CMR, who have repeatedly met to share experience and ideas. The paper aims to assist understanding of acquisition and analysis methods, and their potential clinical applications with a focus on the heart and greater vessels. We describe that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy. We also specify research and development goals that have yet to be satisfactorily achieved. Derived flow parameters, generally needing further development or validation for clinical use, include measurements of wall shear stress, pressure difference, turbulent kinetic energy, and intracardiac flow components. The dependence of measurement accuracy on acquisition parameters is considered, as are the uses of different visualization strategies for appropriate representation of time-varying multidirectional flow fields. Finally, we offer suggestions for more consistent, user-friendly implementation of 4D Flow CMR acquisition and data handling with a view to multicenter studies and more widespread adoption of the approach in routine clinical investigations.

  • 24.
    Fredriksson, Alexandru Grigorescu
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Örebrö University Hospital, Örebro, Sweden.
    Svalbring, Emil
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Eriksson, Jonatan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Alehagen, Urban
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping. Linköping University, Faculty of Medicine and Health Sciences.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Faculty of Science & Engineering. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Carlhäll, Carl-Johan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    4D flow MRI can detect subtle right ventricular dysfunction in primary left ventricular disease.2016In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 43, no 3, p. 558-565Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To investigate whether 4D flow magnetic resonance imaging (MRI) can detect subtle right ventricular (RV) dysfunction in primary left ventricular (LV) disease.

    MATERIALS AND METHODS: 4D flow and morphological 3T MRI data were acquired in 22 patients with mild ischemic heart disease who were stratified into two groups based on LV end-diastolic volume index (EDVI): lower-LVEDVI and higher-LVEDVI, as well as in 11 healthy controls. The RV volume was segmented at end-diastole (ED) and end-systole (ES). Pathlines were emitted from the ED volume and traced forwards and backwards in time to ES. The blood volume was separated into flow components. The Direct Flow (DF) component was defined as RV inflow passing directly to outflow. The kinetic energy (KE) of the DF component was calculated. Echocardiographic conventional RV indices were also assessed.

    RESULTS: The higher-LVEDVI group had larger LVEDVI and lower LV ejection fraction (98 ± 32 ml/m(2) ; 48 ± 13%) compared to the healthy (67 ± 12, P = 0.002; 64 ± 7, P < 0.001) and lower-LVEDI groups (62 ± 10; 68 ± 7, both P < 0.001). The RV 4D flow-specific measures "DF/EDV volume-ratio" and "DF/EDV KE-ratio at ED" were lower in the higher-LVEDVI group (38 ± 5%; 52 ± 6%) compared to the healthy (44 ± 6; 65 ± 7, P = 0.018 and P < 0.001) and lower-LVEDVI groups (44 ± 6; 64 ± 7, P = 0.011 and P < 0.001). There was no difference in any of the conventional MRI and echocardiographic RV indices between the three groups.

    CONCLUSION: We found that in primary LV disease mild impairment of RV function can be detected by 4D flow-specific measures, but not by the conventional MRI and echocardiographic indices. J. Magn. Reson. Imaging 2015.

  • 25.
    Casas Garcia, Belén
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Lantz, Jonas
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Faculty of Science & Engineering. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    4D Flow MRI-Based Pressure Loss Estimation in Stenotic Flows: Evaluation Using Numerical Simulations2016In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 75, no 4, p. 1808-1821Article in journal (Refereed)
    Abstract [en]

    Purpose: To assess how 4D flow MRI-based pressure and energy loss estimates correspond to net transstenotic pressure gradients (TPG(net)) and their dependence on spatial resolution. Methods: Numerical velocity data of stenotic flow were obtained from computational fluid dynamics (CFD) simulations in geometries with varying stenosis degrees, poststenotic diameters and flow rates. MRI measurements were simulated at different spatial resolutions. The simplified and extended Bernoulli equations, Pressure-Poisson equation (PPE), and integration of turbulent kinetic energy (TKE) and viscous dissipation were compared against the true TPG(net). Results: The simplified Bernoulli equation overestimated the true TPG(net) (8.74 +/- 0.67 versus 6.76 +/- 0.54 mmHg). The extended Bernoulli equation performed better (6.57 +/- 0.53 mmHg), although errors remained at low TPG(net). TPG(net) estimations using the PPE were always close to zero. Total TKE and viscous dissipation correlated strongly with TPG(net) for each geometry (r(2) &gt; 0.93) and moderately considering all geometries (r(2) = 0.756 and r(2) = 0.776, respectively). TKE estimates were accurate and minorly impacted by resolution. Viscous dissipation was overall underestimated and resolution dependent. Conclusion: Several parameters overestimate or are not linearly related to TPG(net) and/or depend on spatial resolution. Considering idealized axisymmetric geometries and in absence of noise, TPG(net) was best estimated using the extended Bernoulli equation. (C) 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.

  • 26.
    Qureshi, Fahad
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Alam, Syed Asad
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Gustafsson, Oscar
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    4-k point FFT algorithms based on optimized twiddle factor multiplication for FPGAs2010In: The Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics (PrimeAsia), Shanghai, Sept. 22-24, 2010., 2010, p. 225-228Conference paper (Refereed)
    Abstract [en]

    In this paper, we propose higher point FFT (fast Fourier transform) algorithms for a single delay feedback pipelined FFT architecture considering the 4096-point FFT. These algorithms are different from each other in terms of twiddle factor multiplication. Twiddle factor multiplication complexity comparison is presented when implemented on Field-Programmable Gate Arrays (FPGAs) for all proposed algorithms. We also discuss the design criteria of the twiddle factor multiplication. Finally it is shown that there is a trade-off between twiddle factor memory complexity and switching activity in the introduced algorithms.

  • 27.
    Evaldsson, Chamilly
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Rydén, Ingvar
    Division of Clinical Chemistry, Kalmar County Hospital, Kalmar, Sweden.
    Rosén, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Uppugunduri, Srinivas
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    4-Thiouridine induces dose-dependent reduction of oedema, leucocyte influx and tumour necrosis factor in lung inflammation2009In: Clinical and Experimental Immunology, ISSN 0009-9104, E-ISSN 1365-2249, Vol. 155, no 2, p. 330-338Article in journal (Refereed)
    Abstract [en]

    Recent reports demonstrate a role for nucleotides as inflammatory modulators. Uridine, for example, reduces oedema formation and leucocyte infiltration in a Sephadex-induced lung inflammation model. Tumour necrosis factor (TNF) concentration was also reduced. Previous in vivo observations indicated that 4-thiouridine might have similar effects on leucocyte infiltration and TNF release. The aim of this study was thus to investigate the effects of 4-thiouridine in greater detail. We used a Sephadex-induced acute lung inflammation model in Sprague-Dawley rats. The dextran beads were instilled intratracheally into the lungs, which were excised and examined after 24 h. Sephadex alone led to massive oedema formation and infiltration of macrophages, neutrophils and eosinophils. Microgranulomas with giant cell formations were clearly visible around the partially degraded beads. A significant increase in bronchoalveolar lavage fluid (BALF) content of TNF and leukotrienes was also seen. 4-Thiouridine co-administration affected all variables investigated in this model, i.e. oedema, microscopic and macroscopic appearance of lung tissue, total leucocyte and differential leucocyte counts in BALF, TNF and leukotrienes C-4 (LTC4), LTD4 and LTE4 in BALF, indicating a reproducible anti-inflammatory effect. In conclusion, we have demonstrated that 4-thiouridine has anti-inflammatory effects similar to those of uridine. To our knowledge, this is the first demonstration of pharmacological 4-thiouridine effects in vivo. The results suggest nucleoside/nucleotide involvement in inflammatory processes, warranting further studies on nucleoside analogues as attractive new alternatives in the treatment of inflammatory diseases.

  • 28.
    Haj-Hosseini, Neda
    et al.
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Richter, Johan
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Milos, Peter
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery. Neurokirurgi.
    Hallbeck, Martin
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Clinical pathology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    5-ALA fluorescence and laser Doppler flowmetry for guidance in a stereotactic brain tumor biopsy2018In: Biomedical Optics Express, E-ISSN 2156-7085, Vol. 9, no 5, p. 2284-2296Article in journal (Refereed)
    Abstract [en]

    A fiber optic probe was developed for guidance during stereotactic brain biopsy procedures to target tumor tissue and reduce the risk of hemorrhage. The probe was connected to a setup for the measurement of 5-aminolevulinic acid (5-ALA) induced fluorescence and microvascular blood flow. Along three stereotactic trajectories, fluorescence (n = 109) and laser Doppler flowmetry (LDF) (n = 144) measurements were done in millimeter increments. The recorded signals were compared to histopathology and radiology images. The median ratio of protoporphyrin IX (PpIX) fluorescence and autofluorescence (AF) in the tumor was considerably higher than the marginal zone (17.3 vs 0.9). The blood flow showed two high spots (3%) in total. The proposed setup allows simultaneous and real-time detection of tumor tissue and microvascular blood flow for tracking the vessels.

  • 29.
    Sigfridsson, Andreas
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Escobar Kvitting, John-Peder
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Knutsson, Hans
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Wigström, Lars
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    5D MRI - Cardiac and respiratory time-resolved volume imaging2004In: Proceedings of the annaual conference of the European Society for Magnetic Resonance in Medicine and Biology, 2004Conference paper (Refereed)
    Abstract [en]

    Respiratory motion is often a source of artifacts in cardiovascular imaging, but may also convey important physiological information. To improve our understanding

  • 30.
    Nestor, Colm
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Lentini, Antonio
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Hägg Nilsson, Cathrine
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Gawel, Danuta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Gustafsson, Mika
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Mattson, Lina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Wang, Hui
    MD Anderson Cancer Centre, TX 77030 USA.
    Rundquist, Olof
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Meehan, Richard R.
    University of Edinburgh, Scotland.
    Klocke, Bernward
    Genomatix Software GmbH, Germany.
    Seifert, Martin
    Genomatix Software GmbH, Germany.
    Hauck, Stefanie M.
    German Research Centre Environm Health GmbH, Germany.
    Laumen, Helmut
    Technical University of Munich, Germany; Technical University of Munich, Germany; Helmholtz Zentrum Munchen, Germany; Technical University of Munich, Germany; Technical University of Munich, Germany.
    Zhang, Huan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Benson, Mikael
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Allergy Center.
    5-Hydroxymethylcytosine Remodeling Precedes Lineage Specification during Differentiation of Human CD4(+) T Cells2016In: Cell reports, ISSN 2211-1247, E-ISSN 2211-1247, Vol. 16, no 2, p. 559-570Article in journal (Refereed)
    Abstract [en]

    5-methylcytosine (5mC) is converted to 5-hydroxymethylcytosine (5hmC) by the TET family of enzymes as part of a recently discovered active DNA de-methylation pathway. 5hmC plays important roles in regulation of gene expression and differentiation and has been implicated in T cell malignancies and autoimmunity. Here, we report early and widespread 5mC/5hmC remodeling during human CD4(+) T cell differentiation ex vivo at genes and cell-specific enhancers with known T cell function. We observe similar DNA de-methylation in CD4(+) memory T cells in vivo, indicating that early remodeling events persist long term in differentiated cells. Underscoring their important function, 5hmC loci were highly enriched for genetic variants associated with T cell diseases and T-cell-specific chromosomal interactions. Extensive functional validation of 22 risk variants revealed potentially pathogenic mechanisms in diabetes and multiple sclerosis. Our results support 5hmC-mediated DNA de-methylation as a key component of CD4(+) T cell biology in humans, with important implications for gene regulation and lineage commitment.

  • 31.
    Choudhary, Preetam
    et al.
    Uppsala University, Sweden.
    Routh, Joyanto
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Chakrapani, Govind J.
    Indian Institute Technology, India.
    A 100-year record of changes in organic matter characteristics and productivity in Lake Bhimtal in the Kumaon Himalaya, NW India2013In: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 49, no 2, p. 129-143Article in journal (Refereed)
    Abstract [en]

    Sediment variables total organic carbon (TOC), total nitrogen (TN), total sulfur (TS), as well as their accumulation rates and atomic ratios (C/N and C/S), were studied along with stable isotopes (δ13C, δ15N, and δ34S), and specific biomarkers (n-alkanes and pigments) in a 35-cm-long sediment core from Lake Bhimtal, NW India. The average sedimentation rate is 3.6 mm year−1, and the core represents a provisional record of ~100 years of sedimentation history. Bulk elemental records and their ratios indicate that sediment organic matter (OM) is derived primarily from algae. In-lake productivity increased sharply over the last two decades, consistent with paleoproductivity reconstructions from other lakes in the area. An up-core decrease in δ13C values, despite other evidence for an increase in lake productivity, implies that multiple biogeochemical processes (e.g. external input of sewage or uptake of isotopically depleted CO2 as a result of fossil fuel burning) influence the C isotope record in the lake. The δ15N values (−0.2 to −3.9 ‰) reflect the presence of N-fixing cyanobacteria, and an increase in lake productivity. The δ34S profile shows enrichment of up to 5.6 ‰, and suggests that sulfate reduction occurred in these anoxic sediments. Increases in total n-alkane concentrations and their specific ratios, such as the Carbon Preference Index (CPI) and Terrestrial Aquatic Ratio (TAR), imply in-lake algal production. Likewise, pigments indicate an up-core increase in total concentration and dominance of cyanobacteria over other phytoplankton. Geochemical trends indicate a recent increase in the lake’s trophic state as a result of human-induced changes in the catchment. The study highlights the vulnerability of mountain lakes in the Himalayan region to both natural and anthropogenic processes, and the difficulties associated with reversing trophic state and ecological changes.

  • 32.
    Bhide, Ameya
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    A 11-GS/s 1.1-GHz Bandwidth Interleaved ΔΣ DAC for 60-GHz Radio in 65-nm CMOS2015In: IEEE Journal of Solid-State Circuits, ISSN 0018-9200, E-ISSN 1558-173X, Vol. 50, no 10, p. 2306-2310Article in journal (Refereed)
    Abstract [en]

    This work presents an 11 GS/s 1.1 GHz bandwidth interleaved ΔΣ DAC in 65 nm CMOS for the 60 GHz radio baseband. The high sample rate is achieved by using a two-channel interleaved MASH 1–1 architecture with a 4 bit output resulting in a predominantly digital DAC with only 15 analog current cells. Two-channel interleaving allows the use of a single clock for the logic and the multiplexing which requires each channel to operate at half sampling rate of 5.5 GHz. To enable this, a look-ahead technique is proposed that decouples the two channels within the integrator feedback path thereby improving the speed as compared to conventional loop-unrolling. Measurement results show that the ΔΣ DAC achieves a 53 dB SFDR, -49 dBc IM3 and 39 dB SNDR within a 1.1 GHz bandwidth while consuming 117 mW from 1 V digital/1.2 V analog supplies. Furthermore, the proposed ΔΣ DAC can satisfy the spectral mask of the IEEE 802.11ad WiGig standard with a second order reconstruction filter.

  • 33.
    Nyström, Christine Delisle
    et al.
    Novum, Sweden; Childrens Hosp, Canada.
    Sandin, Sven
    Karolinska Inst, Sweden; Icahn Sch Med Mt Sinai, NY 10029 USA; Seaver Autism Ctr Res and Treatment Mt Sinai, NY 10029 USA.
    Henriksson, Pontus
    Novum, Sweden; Univ Granada, Spain.
    Henriksson, Hanna
    Univ Granada, Spain.
    Maddison, Ralph
    Deakin Univ, Australia.
    Löf, Marie
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Novum, Sweden.
    A 12-month follow-up of a mobile-based (mHealth) obesity prevention intervention in pre-school children: the MINISTOP randomized controlled trial2018In: BMC Public Health, ISSN 1471-2458, E-ISSN 1471-2458, Vol. 18, article id 658Article in journal (Refereed)
    Abstract [en]

    Background: To date, few mobile health (mHealth) interventions aimed at changing lifestyle behaviors have measured long term effectiveness. At the 6-month follow-up the MINISTOP trial found a statistically significant intervention effect for a composite score comprised of fat mass index (FMI) as well as dietary and physical activity variables; however, no intervention effect was observed for FMI. Therefore, the aim of this study was to investigate if the MINISTOP intervention 12-months after baseline measurements: (i) improved FMI and (ii) had a maintained effect on a composite score comprised of FMI and dietary and physical activity variables. Methods: A two-arm parallel randomized controlled trial was conducted in 315 healthy 4.5 year old children between January 2014 and October 2015. Parents of the participating children either received the MINISTOP intervention or a basic pamphlet on dietary and physical activity behaviors (control group). After 6 months, participants did not have access to the intervention content and were measured again 6 months later (i.e. the 12-month follow-up). The Wilcoxon rank-sum test was then used to examine differences between the groups. Results: At the 12-month follow-up, no statistically significant difference was observed between the intervention and control groups for FMI (p = 0.57) and no maintained effect for the change in composite score was observed (mean +/- standard deviation for the intervention and control group: + 0.53 +/- 1.49 units and + 0.35 +/- 1.27 units respectively, p = 0.25 between groups). Conclusions: The intervention effect observed at the 6-month follow-up on the composite score was not maintained at the 12-month follow-up, with no effect on FMI being observed at either follow-up. Future studies using mHealth are needed to investigate how changes in obesity related markers in young children can be maintained over longer time periods.

  • 34.
    Hultman, Martin
    et al.
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Fredriksson, Ingemar
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. Perimed AB, Järfälla-Stockholm, Sweden.
    Larsson, Marcus
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Strömberg, Tomas
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    A 15.6 frames per second 1 megapixel Multiple Exposure Laser Speckle Contrast Imaging setup2018In: Journal of Biophotonics, ISSN 1864-063X, E-ISSN 1864-0648, Vol. 11, no 2, article id e201700069Article in journal (Refereed)
    Abstract [en]

    A multiple exposure laser speckle contrast imaging (MELSCI) setup for visualizing blood perfusion was developed using a field programmable gate array (FPGA), connected to a 1000 frames per second (fps) 1-megapixel camera sensor. Multiple exposure time images at 1, 2, 4, 8, 16, 32 and 64 milliseconds were calculated by cumulative summation of 64 consecutive snapshot images. The local contrast was calculated for all exposure times using regions of 4 × 4 pixels. Averaging of multiple contrast images from the 64-millisecond acquisition was done to improve the signal-to-noise ratio. The results show that with an effective implementation of the algorithm on an FPGA, contrast images at all exposure times can be calculated in only 28 milliseconds. The algorithm was applied to data recorded during a 5 minutes finger occlusion. Expected contrast changes were found during occlusion and the following hyperemia in the occluded finger, while unprovoked fingers showed constant contrast during the experiment. The developed setup is capable of massive data processing on an FPGA that enables processing of MELSCI data in 15.6 fps (1000/64 milliseconds). It also leads to improved frame rates, enhanced image quality and enables the calculation of improved microcirculatory perfusion estimates compared to single exposure time systems.

  • 35.
    Wedajo, W.
    et al.
    Armauer Hansen Research InstituteAddis Ababa, Ethiopia; Department of Biology, Jimma UniversityJimma, Ethiopia.
    Schön, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Department of Infectious Diseases and Microbiology, Kalmar County HospitalKalmar, Sweden.
    Bedru, A.
    Armauer Hansen Research InstituteAddis Ababa, Ethiopia.
    Kiros, T.
    Armauer Hansen Research InstituteAddis Ababa, Ethiopia.
    Hailu, E.
    Armauer Hansen Research Institute Addis Ababa, Ethiopia.
    Mebrahtu, T.
    Armauer Hansen Research Institute Addis Ababa, Ethiopia.
    Yamuah, L.
    Armauer Hansen Research Institute Addis Ababa, Ethiopia.
    Angeby, K.
    Department of Clinical Microbiology MTC, Karolinska Hospital, Karolinska University HospitalStockholm, Sweden.
    Werngren, J.
    Department of Preparedness, Unit of Highly Pathogenic Microorganisms, Swedish Institute for Communicable Disease Control (SMI)Solna, Sweden.
    Onyebujoh, P.
    World Health Organization, Regional Office for Africa, Inter-country Support Team for East0/Southern AfricaHarare, Zimbabwe.
    Dagne, K.
    Addis Ababa University, Faculty of Life SciencesAddis Ababa, Ethiopia.
    Aseffa, A.
    Armauer Hansen Research Institute Addis Ababa, Ethiopia.
    A 24-well plate assay for simultaneous testing of first and second line drugs against Mycobacterium tuberculosis in a high endemic setting2014In: BMC Research Notes, ISSN 1756-0500, E-ISSN 1756-0500, Vol. 7, no 1, p. 512-Article in journal (Refereed)
    Abstract [en]

    Background: Early detection of drug resistance is one of the priorities of tuberculosis (TB) control programs as drug resistance is increasing. New molecular assays are only accessible for a minority of the second line drugs and their availability in high endemic settings is also hampered by high cost and logistic challenges. Therefore, we evaluated a previously developed method for drug susceptibility testing (DST) including both first- and second line anti-TB drugs for use in high endemic areas. Results: Baseline mycobacterial isolates from 78 consecutive pulmonary TB patients from Addis Ababa, Ethiopia who were culture positive for Mycobacterium tuberculosis at the end of a two-month directly observed treatment short course (DOTS) were included. The isolates were simultaneously tested for isoniazid, rifampicin, ethambutol, streptomycin, amikacin, kanamycin, capreomycin, ofloxacin, moxifloxacin, ethionamide and para-aminosalicylic acid susceptibility using the indirect proportion method adopted for 24-well agar plates containing Middlebrook 7H10 medium. Applying the 24-well plate assay, 43 (55.1%) isolates were resistant to one or more of the first line drugs tested (isoniazid, rifampicin and ethambutol). MDR-TB was identified in 20.5% of this selected group and there was a perfect correlation for rifampicin resistance with the results from the genotype MTBDRplus assay. All isolates were susceptible to aminoglycosides and fluoroquinolones in agreement with the genotype MTBDRsl assay. The only tested second line drug associated to resistance was ethionamide (14.1% resistant). The method was reproducible with stable results for internal controls (one multi-drug resistant (MDR) and one pan-susceptible strain (H37Rv) and DST results could be reported at two weeks. Conclusions: The 24-well plate method for simultaneous DST for first- and second line drugs was found to be reproducible and correlated well to molecular drug susceptibility tests. It is likely to be useful in high-endemic areas for surveillance as well as for the detection of second line drug resistance in targeted groups such as in those who fail empirical MDR treatment.

  • 36.
    Ziemssen, Tjalf
    et al.
    Klinikum Carl Gustav Carus, Germany.
    Bajenaru, Ovidiu A.
    Carol Davila University of Medical and Pharm, Romania.
    Carra, Adriana
    Hospital Britanico Buenos Aires, Argentina.
    de Klippel, Nina
    Virga Jessaziekenhuis, Belgium.
    de Sa, Joao C.
    Hospital Santa Mari, Belgium.
    Edland, Astrid
    Central Hospital Buskerud, Norway.
    Frederiksen, Jette L.
    University of Copenhagen, Denmark.
    Heinzlef, Olivier
    Hop Tenon, France.
    Karageorgiou, Klimentini E.
    Gen Hospital Athens, Greece.
    Lander Delgado, Rafael H.
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Macias Islas, Miguel A.
    Central University of Guadalajara, Mexico.
    Tubridy, Niall
    Dublin City University, Ireland.
    Gilgun-Sherki, Yossi
    Teva Pharmaceut Ind Ltd, Israel.
    A 2-year observational study of patients with relapsing-remitting multiple sclerosis converting to glatiramer acetate from other disease-modifying therapies: the COPTIMIZE trial2014In: Journal of Neurology, ISSN 0340-5354, E-ISSN 1432-1459, Vol. 261, no 11, p. 2101-2111Article in journal (Refereed)
    Abstract [en]

    Studies suggest that patients with relapsing-remitting multiple sclerosis (RRMS) who do not benefit from other disease-modifying treatments (DMTs) may benefit from converting to glatiramer acetate (GA). COPTIMIZE was a 24-month observational study designed to assess the disease course of patients converting to GA 20 mg daily from another DMT. Eligible patients had converted to GA and had received prior DMT for 3-6 months, depending on the reasons for conversion. Patients were assessed at baseline and at 6, 12, 18, and 24 months. In total, 672 patients from 148 centers worldwide were included in the analysis. Change of therapy to GA was prompted primarily by lack of efficacy (53.6 %) or intolerable adverse events (AEs; 44.8 %). Over a 24-month period, 72.7 % of patients were relapse free. Mean annual relapse rate decreased from 0.86 [95 % confidence interval (CI) 0.81-0.91] before the change to 0.32 (95 % CI 0.26-0.40; p less than 0.0001) at last observation, while the progression of disability was halted, as the Kurtzke Expanded Disability Status Scale (EDSS) scores remained stable. Patients improved significantly (p less than 0.05) on measures of fatigue, quality of life, depression, and cognition; mobility scores remained stable. The results indicate that changing RRMS patients to GA is associated with positive treatment outcomes.

  • 37.
    Fritzin, Jonas
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 3.3 V 72.2 Mbit/s 802.11n WLAN transformer-based power amplifier in 65 nm CMOS2010In: Analog Integrated Circuits and Signal Processing, ISSN 0925-1030, E-ISSN 1573-1979, Vol. 64, no 3, p. 241-247Article in journal (Refereed)
    Abstract [en]

    This paper describes the design of a power amplifier (PA) for 802.11n WLAN fabricated in 65 nm CMOS technology. The PA utilizes 3.3 V thick gate oxide (5.2 nm) transistors and a two-stage differential configuration with integrated transformers for input and interstage matching. A methodology used to extract the layout parasitics from electromagnetic (EM) simulations is described. For a 72.2 Mbit/s, 64-QAM, 802.11n OFDM signal at an average and peak output power of 11.6 and 19.6 dBm, respectively, the measured EVM is 3.8%. The PA meets the spectral mask up to an average output power of 17 dBm.

  • 38.
    Garrido Gálvez, Mario
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Angel Sanchez, Miguel
    University of Politecn Madrid, Spain.
    Luisa Lopez-Vallejo, Maria
    University of Politecn Madrid, Spain.
    Grajal, Jesus
    University of Politecn Madrid, Spain.
    A 4096-Point Radix-4 Memory-Based FFT Using DSP Slices2017In: IEEE Transactions on Very Large Scale Integration (vlsi) Systems, ISSN 1063-8210, E-ISSN 1557-9999, Vol. 25, no 1, p. 375-379Article in journal (Refereed)
    Abstract [en]

    This brief presents a novel 4096-point radix-4 memory-based fast Fourier transform (FFT). The proposed architecture follows a conflict-free strategy that only requires a total memory of size N and a few additional multiplexers. The control is also simple, as it is generated directly from the bits of a counter. Apart from the low complexity, the FFT has been implemented on a Virtex-5 field programmable gate array (FPGA) using DSP slices. The goal has been to reduce the use of distributed logic, which is scarce in the target FPGA. With this purpose, most of the hardware has been implemented in DSP48E. As a result, the proposed FPGA is efficient in terms of hardware resources, as is shown by the experimental results.

  • 39.
    Ahmed, Tanvir
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, Faculty of Science & Engineering.
    Garrido, Mario
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Gustafsson, Oscar
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A 512-point 8-parallel pipelined feedforward FFT for WPAN2011In: 2011 Conference Record of the Forty Fifth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), IEEE , 2011, p. 981-984Conference paper (Refereed)
    Abstract [en]

    This paper presents a 512-point feedforward FFT architecture for wireless personal area network (WPAN). The architecture processes a continuous flow of 8 samples in parallel, leading to a throughput of 2.64 GSamples/s. The FFT is computed in three stages that use radix-8 butterflies. This radix reduces significantly the number of rotators with respect to previous approaches based on radix-2. Besides, the proposed architecture uses the minimum memory that is required for a 512-point 8-parallel FFT. Experimental results show that besides its high throughput, the design is efficient in area and power consumption, improving the results of previous approaches. Specifically, for a wordlength of 16 bits, the proposed design consumes 61.5 mW and its area is 1.43 mm2.

  • 40.
    Zhang, Dai
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Bhide, Ameya
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 53-nW 9.1-ENOB 1-kS/s SAR ADC in 0.13-μm CMOS for Medical Implant Devices2012In: IEEE Journal of Solid-State Circuits, ISSN 0018-9200, E-ISSN 1558-173X, Vol. 47, no 7, p. 1585-1593Article in journal (Refereed)
    Abstract [en]

    This paper describes an ultra-low power SAR ADC for medical implant devices. To achieve the nano-watt range power consumption, an ultra-low power design strategy has been utilized, imposing maximum simplicity on the ADC architecture, low transistor count and matched capacitive DAC with a switching scheme which results in full-range sampling without switch boot-strapping and extra reset voltage. Furthermore, a dual-supply voltage scheme allows the SAR logic to operate at 0.4 V, reducing the overall power consumption of the ADC by 15% without any loss in performance. The ADC was fabricated in 0.13-mu m CMOS. In dual-supply mode (1.0 V for analog and 0.4 V for digital), the ADC consumes 53 nW at a sampling rate of 1 kS/s and achieves the ENOB of 9.1 bits. The leakage power constitutes 25% of the 53-nW total power.

  • 41.
    Sundström, Timmy
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 6‐bit 2.5‐GS/s Flash ADC using Comparator Redundancy for Low Power in 90nm CMOS2010In: Analog Integrated Circuits and Signal Processing, ISSN 0925-1030, E-ISSN 1573-1979, Vol. 64, no 3, p. 215-222Article in journal (Refereed)
    Abstract [en]

    A 2.5 GS/s flash ADC, fabricated in 90nm CMOS utilizes comparator redundancy to avoid traditional power, speed and accuracy trade‐offs. The redundancy removes the need to control comparator offsets, allowing the large process‐variation induced mismatch of small devices in nanometer technologies. This enables the use of small‐sized, ultra‐low‐power comparators with clock‐gating capabilities in order to reduce the power dissipation. The chosen calibration method enables an overall low‐power solution and measurement results show that the ADC dissipates 30 mW at 1.2 V. With 63 comparators, the ADC achieves 3.9 effective number of bits.

  • 42.
    Hu, Xiao-Li
    et al.
    Chinese Academy of Sciences, China.
    Schön, Thomas
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Ljung, Lennart
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Basic Convergence Result for Particle Filtering2008In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 56, no 4, p. 1337-1348Article in journal (Refereed)
    Abstract [en]

    The basic nonlinear filtering problem for dynamical systems is considered. Approximating the optimal filter estimate by particle filter methods has become perhaps the most common and useful method in recent years. Many variants of particle filters have been suggested, and there is an extensive literature on the theoretical aspects of the quality of the approximation. Still a clear-cut result that the approximate solution, for unbounded functions, converges to the true optimal estimate as the number of particles tends to infinity seems to be lacking. It is the purpose of this contribution to give such a basic convergence result for a rather general class of unbounded functions. Furthermore, a general framework, including many of the particle filter algorithms as special cases, is given.

  • 43.
    Lindström, Tom
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Grear, Daniel A.
    Colorado State University, USA .
    Buhnerkempe, Michael
    Colorado State University, USA .
    Webb, Colleen T.
    Colorado State University, USA .
    Miller, Ryan S.
    US Anim and Plant Health Inspect Serv, CO USA .
    Portacci, Katie
    US Anim and Plant Health Inspect Serv, CO USA .
    Wennergren, Uno
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    A Bayesian Approach for Modeling Cattle Movements in the United States: Scaling up a Partially Observed Network2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 1Article in journal (Refereed)
    Abstract [en]

    Networks are rarely completely observed and prediction of unobserved edges is an important problem, especially in disease spread modeling where networks are used to represent the pattern of contacts. We focus on a partially observed cattle movement network in the U.S. and present a method for scaling up to a full network based on Bayesian inference, with the aim of informing epidemic disease spread models in the United States. The observed network is a 10% state stratified sample of Interstate Certificates of Veterinary Inspection that are required for interstate movement; describing approximately 20,000 movements from 47 of the contiguous states, with origins and destinations aggregated at the county level. We address how to scale up the 10% sample and predict unobserved intrastate movements based on observed movement distances. Edge prediction based on a distance kernel is not straightforward because the probability of movement does not always decline monotonically with distance due to underlying industry infrastructure. Hence, we propose a spatially explicit model where the probability of movement depends on distance, number of premises per county and historical imports of animals. Our model performs well in recapturing overall metrics of the observed network at the node level (U.S. counties), including degree centrality and betweenness; and performs better compared to randomized networks. Kernel generated movement networks also recapture observed global network metrics, including network size, transitivity, reciprocity, and assortativity better than randomized networks. In addition, predicted movements are similar to observed when aggregated at the state level (a broader geographic level relevant for policy) and are concentrated around states where key infrastructures, such as feedlots, are common. We conclude that the method generally performs well in predicting both coarse geographical patterns and network structure and is a promising method to generate full networks that incorporate the uncertainty of sampled and unobserved contacts.

  • 44.
    Zografos, Vasileios
    et al.
    University College London.
    Buxton, Bernard
    University College London.
    A Bayesian Approach to 3D Object Recognition Using Linear Combination of 2D Views2008In: International Conference on computer vision theory and applications, 2008, p. 295-298Conference paper (Refereed)
  • 45.
    Özkan, Emre
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Lundquist, Christian
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Bayesian Approach to Jointly Estimate Tire Radii and Vehicle Trajectory2011In: Proceedings of the International IEEE Conference on Intelligent Transportation Systems, Washington DC, USA: IEEE conference proceedings, 2011, p. 1-6Conference paper (Refereed)
    Abstract [en]

    High-precision estimation of vehicle tire radii is considered, based on measurements on individual wheel speeds and absolute position from a global navigation satellite system (GNSS). The wheel speed measurements are subject to noise with time-varying covariance that depends mainly on the road surface. The novelty lies in a Bayesian approach to estimate online the time-varying radii and noise parameters using a marginalized particle filter, where no model approximations are needed such as in previously proposed algorithms based on the extended Kalman filter. Field tests show that the absolute radius can be estimated with millimeter accuracy, while the relative wheel radius on one axle is estimated with submillimeter accuracy.

  • 46.
    Axell, Erik
    et al.
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, The Institute of Technology.
    Larsson, Erik G.
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, The Institute of Technology.
    A Bayesian Approach to Spectrum Sensing, Denoising and Anomaly Detection2009In: Proceedings of the 34th IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP'09), 2009, p. 2333-2336Conference paper (Refereed)
    Abstract [en]

    This paper deals with the problem of discriminating samples that contain only noise from samples that contain a signal embedded in noise. The focus is on the case when the variance of the noise is unknown. We derive the optimal soft decision detector using a Bayesian approach. The complexity of this optimal detector grows exponentially with the number of observations and as a remedy, we propose a number of approximations to it. The problem under study is a fundamental one and it has applications in signal denoising, anomaly detection, and spectrum sensing for cognitive radio. We illustrate the results in the context of the latter.

  • 47.
    Lindström, Tom
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, Faculty of Science & Engineering. Colorado State University, CO 80523 USA; US National Institute Heatlh, MD USA; University of Exeter, England.
    Tildesley, Michael
    US National Institute Heatlh, MD USA; University of Nottingham, England.
    Webb, Colleen
    Colorado State University, CO 80523 USA; US National Institute Heatlh, MD USA.
    A Bayesian Ensemble Approach for Epidemiological Projections2015In: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 11, no 4, p. e1004187-Article in journal (Refereed)
    Abstract [en]

    Mathematical models are powerful tools for epidemiology and can be used to compare control actions. However, different models and model parameterizations may provide different prediction of outcomes. In other fields of research, ensemble modeling has been used to combine multiple projections. We explore the possibility of applying such methods to epidemiology by adapting Bayesian techniques developed for climate forecasting. We exemplify the implementation with single model ensembles based on different parameterizations of the Warwick model run for the 2001 United Kingdom foot and mouth disease outbreak and compare the efficacy of different control actions. This allows us to investigate the effect that discrepancy among projections based on different modeling assumptions has on the ensemble prediction. A sensitivity analysis showed that the choice of prior can have a pronounced effect on the posterior estimates of quantities of interest, in particular for ensembles with large discrepancy among projections. However, by using a hierarchical extension of the method we show that prior sensitivity can be circumvented. We further extend the method to include a priori beliefs about different modeling assumptions and demonstrate that the effect of this can have different consequences depending on the discrepancy among projections. We propose that the method is a promising analytical tool for ensemble modeling of disease outbreaks.

  • 48.
    Eklund, Anders
    et al.
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Science & Engineering. Linköping University, Faculty of Arts and Sciences.
    Lindqvist, Martin A
    Department of Biostatistics, Johns Hopkins University, Baltimore, USA.
    Villani, Mattias
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    A Bayesian Heteroscedastic GLM with Application to fMRI Data with Motion Spikes2017In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 155, p. 354-369Article in journal (Refereed)
    Abstract [en]

    We propose a voxel-wise general linear model with autoregressive noise and heteroscedastic noise innovations (GLMH) for analyzing functional magnetic resonance imaging (fMRI) data. The model is analyzed from a Bayesian perspective and has the benefit of automatically down-weighting time points close to motion spikes in a data-driven manner. We develop a highly efficient Markov Chain Monte Carlo (MCMC) algorithm that allows for Bayesian variable selection among the regressors to model both the mean (i.e., the design matrix) and variance. This makes it possible to include a broad range of explanatory variables in both the mean and variance (e.g., time trends, activation stimuli, head motion parameters and their temporal derivatives), and to compute the posterior probability of inclusion from the MCMC output. Variable selection is also applied to the lags in the autoregressive noise process, making it possible to infer the lag order from the data simultaneously with all other model parameters. We use both simulated data and real fMRI data from OpenfMRI to illustrate the importance of proper modeling of heteroscedasticity in fMRI data analysis. Our results show that the GLMH tends to detect more brain activity, compared to its homoscedastic counterpart, by allowing the variance to change over time depending on the degree of head motion.

  • 49.
    Bergkvist, Liza
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Sandin, Linnea
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Kågedal, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    A beta PP processing results in greater toxicity per amount of A beta(1-42) than individually expressed and secreted A beta(1-42) in Drosophila melanogaster2016In: BIOLOGY OPEN, ISSN 2046-6390, Vol. 5, no 8, p. 1030-1039Article in journal (Refereed)
    Abstract [en]

    The aggregation of the amyloid-beta (A beta) peptide into fibrillar deposits has long been considered the key neuropathological hallmark of Alzheimers disease (AD). A beta peptides are generated from proteolytic processing of the transmembrane A beta precursor protein (A beta PP) via sequential proteolysis through the beta-secretase activity of beta-site A beta PP-cleaving enzyme (BACE1) and by the intramembranous enzyme gamma-secretase. For over a decade, Drosophila melanogaster has been used as a model organism to study AD, and two different approaches have been developed to investigate the toxicity caused by AD-associated gene products in vivo. In one model, the A beta peptide is directly over-expressed fused to a signal peptide, allowing secretion of the peptide into the extracellular space. In the other model, human A beta PP is co-expressed with human BACE1, resulting in production of the A beta peptide through the processing of A beta PP by BACE1 and by endogenous fly gamma-secretase. Here, we performed a parallel study of flies that expressed the A beta(1-42) peptide alone or that co-expressed A beta PP and BACE1. Toxic effects (assessed by eye phenotype, longevity and locomotor assays) and levels of the A beta(1-42), A beta(1-40) and A beta(1-38) peptides were examined. Our data reveal that the toxic effect per amount of detected A beta(1-42) peptide was higher in the flies co-expressing A beta PP and BACE1 than in the A beta(1-42)-expressing flies, and that the co-existence of A beta(1-42) and A beta(1-40) in the flies co-expressing A beta PP and BACE1 could be of significant importance to the neurotoxic effect detected in these flies. Thus, the toxicity detected in these two fly models seems to have different modes of action and is highly dependent on how and where the peptide is generated rather than on the actual level of the A beta(1-42) peptide in the flies. This is important knowledge that needs to be taken into consideration when using Drosophila models to investigate disease mechanisms or therapeutic strategies in AD research.

  • 50.
    Saifullah, Mohammad
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    A Biologically Inspired Model for Occluded Patterns2011In: Neural Information Processing: proceedings of the 18th International Conference on Neural Information Processing, ICONIP 2011,  Shanghai, China, November 2011. / [ed] Lu, Bao-Liang, Zhang, Liqing, Kwok, James, Springer Berlin/Heidelberg, 2011, p. 88-96Conference paper (Refereed)
    Abstract [en]

    In this paper a biologically-inspired model for partly occluded patterns is proposed. The model is based on the hypothesis that in human visual system occluding patterns play a key role in recognition as well as in reconstructing internal representation for a pattern’s occluding parts. The proposed model is realized with a bidirectional hierarchical neural network. In this network top-down cues, generated by direct connections from the lower to higher levels of hierarchy, interact with the bottom-up information, generated from the un-occluded parts, to recognize occluded patterns. Moreover, positional cues of the occluded as well as occluding patterns, that are computed separately but in the same network, modulate the top-down and bottom-up processing to reconstruct the occluded patterns. Simulation results support the presented hypothesis as well as effectiveness of the model in providing a solution to recognition of occluded patterns. The behavior of the model is in accordance to the known human behavior on the occluded patterns.

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