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Sökning: WFRF:(Nilsson Rikard)

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1.
  • Abudayyeh, H.A., et al. (författare)
  • Centrifugal acceleration at high altitudes above the polar cap : A Monte Carlo simulation
  • 2015
  • Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 120:8, s. 6409-6426
  • Tidskriftsartikel (refereegranskat)abstract
    • A Monte Carlo simulation was used to study the outflow of O+ and H+ ions along three flight trajectories above the polar cap up to altitudes of about 15 RE. Barghouthi (2008) developed a model on the basis of altitude and velocity-dependent wave-particle interactions and a radial geomagnetic field which includes the effects of ambipolar electric field and gravitational and mirror forces. In the present work we improve this model to include the effect of the centrifugal force, with the use of relevant boundary conditions. In addition, the magnetic field and flight trajectories, namely, the central polar cap (CPC), nightside polar cap (NPC), and cusp, were calculated using the Tsyganenko T96 model. To simulate wave-particle interactions, the perpendicular velocity diffusion coefficients for O+ ions in each region were determined such that the simulation results fit the observations. For H+ ions, a constant perpendicular velocity diffusion coefficient was assumed for all altitudes in all regions as recommended by Nilsson et al. (2013). The effect of centrifugal acceleration was simulated by considering three values for the ionospheric electric field: 0 (no centrifugal acceleration), 50, and 100 mV/m. It was found that the centrifugal acceleration increases the parallel bulk velocity and decreases the parallel and perpendicular temperatures of both ion species at altitudes above about 4 RE. Centrifugal acceleration also increases the temperature anisotropy at high altitudes. At a given altitude, centrifugal acceleration decreases the density of H+ ions while it increases the density of O+ ions. This implies that with higher centrifugal acceleration more O+ ions overcome the potential barrier. It was also found that aside from two exceptions centrifugal acceleration has the same effect on the velocities of both ions. This implies that the centrifugal acceleration is universal for all particles. The parallel bulk velocities at a given value of ionospheric electric field were highest in the cusp followed by the CPC followed by the NPC. In this study a region of no wave-particle interaction was assumed in the CPC and NPC between 3.7 and 7.5 RE. In this region the perpendicular temperature was found to decrease with altitude due to perpendicular adiabatic cooling.
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2.
  • Apell, Jeanette, et al. (författare)
  • Mätning av barns oro vid undersökning eller behandling på sjukhus : en studie som utvärderar short STAI
  • 2011
  • Ingår i: Vård i Norden. - : Sykepleiernes Samarbeid i Norden. - 0107-4083 .- 1890-4238. ; 31:1, s. 45-47
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: The purpose was to investigate the validity and reliability of short STAI (State-Trait Anxiety Inventory) for measuring children's anxiety in connection with procedures in hospital. Background: The children´s level of anxiety during hospitalization can cause problems and it should be evaluated with a valid and reliable instrument. STAIC-S (STAI for children) has previously been validated in children for this purpose but may be too complex to use. Short STAI has only been evaluated in adults and should be tested in children before it can be used. Methods: Children aged five to 16 filled in both STAIC-S and short STAI before and after an examination or treatment at the hospital. Results: Twenty children were included. Satisfactory internal reliability was found for short STAI with Cronbachs’s alpha 0.82. Correlation coefficients between the instruments were 0.88 before and 0.75 after the procedure. Significantly lower values were found after compared to before demonstrating constructive validity. Short STAI was easy to fill in but seven of 16 participants received help from their parents. Conclusion: Short STAI was shown to be a reliable and valid instrument for measuring anxiety in children, but a larger study is needed to confirm the validity and reliability further
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3.
  • Ardö, Håkan, et al. (författare)
  • Flow Counting Using Realboosted Multi-sized Window Detectors
  • 2012
  • Ingår i: Computer Vision – ECCV 2012. Workshops and Demonstrations : Florence, Italy, October 7-13, 2012, Proceedings, Part III - Florence, Italy, October 7-13, 2012, Proceedings, Part III. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783642338847 - 9783642338854 ; 7585, s. 193-202
  • Konferensbidrag (refereegranskat)abstract
    • One classic approach to real-time object detection is to use adaboost to a train a set of look up tables of discrete features. By utilizing a discrete feature set, from features such as local binary patterns, efficient classifiers can be designed. However, these classifiers include interpolation operations while scaling the images over various scales. In this work, we propose the use of real valued weak classifiers which are designed on different scales in order to avoid costly interpolations. The use of real valued weak classifiers in combination with the proposed method avoiding interpolation leads to substantially faster detectors compared to baseline detectors. Furthermore, we investigate the speed and detection performance of such classifiers and their impact on tracking performance. Results indicate that the realboost framework combined with the proposed scaling framework achieves an 80% speed up over adaboost with bilinear interpolation.
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4.
  • Aspenberg, David, et al. (författare)
  • An evaluation of the statistics of steel material model parameters
  • 2012
  • Ingår i: Journal of Materials Processing Technology. - : Elsevier. - 0924-0136 .- 1873-4774. ; 212:6, s. 1288-1297
  • Tidskriftsartikel (refereegranskat)abstract
    • In robustness studies, variations of material properties are often represented by simple assumptions, such as scaling of stress-strain relations, often due to lack of knowledge or deeper understanding of the material physics and the material model applied. By performing material characterisation tests on several batches of a DP600 steel and fitting a phenomenological material model to each batch, this paper studies the dispersion of material model parameters, as well as correlations between both experimental and model parameters. It is concluded that some of the charcterisation tests may be omitted in the future, due to correlations found between parameters. The results may also be applied in a robustness study by inversely using the retrieved statistics to generate reasonable new sets of material model parameters. The methodology presented may be adopted for any other type of material characterisation process.
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5.
  • Barghouthi, Imad A., et al. (författare)
  • O+ and H+ above the polar cap : Observations and semikinetic simulations
  • 2016
  • Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 121:1, s. 459-474
  • Tidskriftsartikel (refereegranskat)abstract
    • A 1-dimensional direct simulation Monte Carlo model is used to study the outflow of O+ and H+ ions from 1.2 RE to 15.2 RE along two flight trajectories originating from the polar cap, namely the central polar cap (CPC) and the cusp. To study the effect of varying geophysical conditions and to deduce the proper set of parameters. several parameters were varied and the results were compared to corresponding data from Cluster spacecraft. First, several sets of diffusion coefficients were considered based on using diffusion coefficients calculated by Barghouthi et al. [1998], Nilsson et al. [2013], and Abudayyeh et al. [2015b] for different altitude intervals. It was found that in the central polar cap using the diffusion coefficients reported by Barghouthi et al. [1998] for altitudes lower than 3.7 RE, zero diffusion coefficients between 3.7 and 7.5 RE and diffusion coefficients from Nilsson et al. [2013] for altitudes higher than 7.5 RE provide the best fit for O+ ions. For O+ ions in the cusp the best fit was obtained for using Barghouthi et al. [1998] diffusion coefficients for altitudes lower than 3.7 RE and Nilsson et al. [2013] diffusion coefficients for altitudes higher than that. The best fit for H+ ions in both regions was obtained by using the diffusion coefficients calculated by Abudayyeh et al. [2015b]. Also, it was found that along an ion's trajectory the most recent heating dominates. Second, the strength of centrifugal acceleration was varied by using three values for the ionospheric electric field namely: 0, 50, and 100 mV/m. It was found that the value of 50 mV/m provided the best fit for both ion species in both regions. Finally the lower altitude boundary conditions and the electron temperature were varied. Increasing the electron temperature and the lower altitude O+ parallel velocity were found to increase the access of O+ ions to higher altitudes and therefore increase the density at a given altitude. The variation of all other boundary conditions only affected the densities of the ions and not the other moments due to the overwhelming effect of wave particle interaction. Furthermore varying the parameters of one ion species has no effect on the other ion species. We also compared the energy gain per ion due to wave particle interaction, centrifugal acceleration, and ambipolar electric field and found that wave particle interaction is the most important mechanism, while ambipolar electric field is relatively unimportant especially at higher altitudes.
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6.
  • Bayani, Mohsen, 1981, et al. (författare)
  • A strategy for developing an inclusive load case for verification of squeak and rattle noises in the car cabin
  • 2021
  • Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
  • Konferensbidrag (refereegranskat)abstract
    • Squeak and rattle (S&R) are nonstationary annoying and unwanted noises in the car cabin that result in considerable warranty costs for car manufacturers. Introduction of cars with remarkably lower background noises and the recent emphasis on electrification and autonomous driving further stress the need for producing squeak- and rattle-free cars. Automotive manufacturers use several road disturbances for physical evaluation and verification of S&R. The excitation signals collected from these road profiles are also employed in subsystem shaker rigs and virtual simulations that are gradually replacing physical complete vehicle test and verification. Considering the need for a shorter lead time and the introduction of optimisation loops, it is necessary to have efficient and inclusive excitation load cases for robust S&R evaluation. In this study, a method is proposed to truncate and identify the important parts of the different road profiles that are often used for S&R physical verification and then merge them to develop one representative excitation load case. The criteria for signal truncation were based on the S&R risk and severity metrics calculated from the vibration response at the critical interfaces for S&R. the method was used in a case study involving the instrument panel of a passenger car. Results of the virtual simulation and the rig tests were compared with the complete vehicle test. The proposed synthesised signal generation strategy was validated by physical testing through measuring vibration signals. The results supported the possibility of replacing multiple S&R excitation signals with one single representative inclusive signal, while the quality of S&R risk prediction from the system response was maintained. The outcome of this work can lead to a more efficient physical and virtual S&R verification in the development process of passenger cars.
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7.
  • Bergh, Cecilia, 1972-, et al. (författare)
  • Effects of Bilberry and Oat intake on lipids, inflammation and exercise capacity after Acute Myocardial Infarction (BIOAMI): study protocol for a randomized, double-blind, placebo-controlled trial
  • 2021
  • Ingår i: Trials. - : Springer Science and Business Media LLC. - 1745-6215 .- 1745-6215. ; 22:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Bilberries from Sweden, rich in polyphenols, have shown cholesterol-lowering effects in small studies, and the cholesterol-lowering properties of oats, with abundant beta-glucans and potentially bioactive phytochemicals, are well established. Both may provide cardiometabolic benefits following acute myocardial infarction (AMI), but large studies of adequate statistical power and appropriate duration are needed to confirm clinically relevant treatment effects. No previous study has evaluated the potential additive or synergistic effects of bilberry combined with oats on cardiometabolic risk factors. Our primary objective is to assess cardioprotective effects of diet supplementation with dried bilberry or with bioprocessed oat bran, with a secondary explorative objective of assessing their combination, compared with a neutral isocaloric reference supplement, initiated within 5 days following percutaneous coronary intervention (PCI) for AMI. Methods: The effects of Bilberry and Oat intake on lipids, inflammation and exercise capacity after Acute Myocardial Infarction (BIOAMI) trial is a double-blind, randomized, placebo-controlled clinical trial. A total of 900 patients will be randomized post-PCI to one of four dietary intervention arms. After randomization, subjects will receive beverages with bilberry powder (active), beverages with high-fiber bioprocessed oat bran (active), beverages with bilberry and oats combined (active), or reference beverages containing no active bilberry or active oats, for consumption twice daily during a 3-month intervention. The primary endpoint is the difference in LDL cholesterol change between the intervention groups after 3 months. The major secondary endpoint is exercise capacity at 3 months. Other secondary endpoints include plasma concentrations of biochemical markers of inflammation, metabolomics, and gut microbiota composition after 3 months. Discussion: Controlling hyperlipidemia and inflammation is critical to preventing new cardiovascular events, but novel pharmacological treatments for these conditions are expensive and associated with negative side effects. If bilberry and/or oat, in addition to standard medical therapy, can lower LDL cholesterol and inflammation more than standard therapy alone, this could be a cost-effective and safe dietary strategy for secondary prevention after AMI. Trial registration: ClinicalTrials.gov NCT03620266. Registered on August 8, 2018.
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8.
  • Björklund, Oscar, et al. (författare)
  • Failure of high strength steel sheets : Experiments and modelling
  • 2013
  • Ingår i: Journal of Materials Processing Technology. - : Elsevier BV. - 0924-0136 .- 1873-4774. ; 213:7, s. 1103-1117
  • Tidskriftsartikel (refereegranskat)abstract
    • Failure in sheet metal structures of ductile material is usually caused by one of, or a combination of, ductile fracture, shear fracture or localised instability. In this paper the failure of the high strength steel Docol 600DP and the ultra high strength steel Docol 1200M is explored. The constitutive model used in this study includes plastic anisotropy and mixed isotropic-kinematic hardening. For modelling of the ductile and shear fracture the models presented by Cockroft–Latham and Bressan–Williams have been used. The instability phenomenon is described by the constitutive law and the finite element (FE) models. For calibration of the failure models and validation of the results, an extensive experimental series has been conducted including shear tests, plane strain tests and Nakajima tests. The geometries of the Nakajima tests have been chosen so that the first quadrant of the forming limit diagram (FLD) were covered. The results are presented both in an FLD and using prediction of force–displacement response of the Nakajima test employing element erosion during the FE simulations. The classical approach for failure prediction is to compare the principal plastic strains obtained from FE simulations with experimental determined forming limit curves (FLCs). It is well known that the experimental FLC requires proportional strains to be useful. In this work failure criteria, both of the instability and fracture, are proposed which can be used also for non-proportional strain paths.
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9.
  • Blomsterberg, Åke, et al. (författare)
  • Energi- och Miljörenovering av miljonprogramshus - Backa Röd i Göteborg
  • 2015
  • Ingår i: Bygg & teknik. - 0281-658X. ; , s. 46-51
  • Tidskriftsartikel (populärvet., debatt m.m.)abstract
    • I Sverige finns ett stort bostadsbestånd som står inför ombyggnad. Miljonprogrammets bostäder är över 40 år gamla och behöver rustas upp. Det är angeläget att denna upprustning utformas på ett sådant sätt att husen byggs om till energieffektiva byggnader med låga framtida drifts- och uppvärmningskostnader och med låg miljöpåverkan under hela livscykeln. Det är i sammanhanget viktigt att energieffektivisering av byggnaderna genomförs samtidigt som husen renoveras för att åtgärderna ska kunna genomföras till rimliga kostnader. För detta behövs nya metoder för kostnadseffektiv energi- och miljörenovering. Sverige deltar i ett internationellt forskningsprojekt med detta syfte, IEA Annex 56.
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10.
  • Borg Karlson, A. K., et al. (författare)
  • Floral fragrance chemistry in the early flowering shrub Daphne mezereum
  • 1996
  • Ingår i: Phytochemistry. - : Elsevier BV. - 0031-9422 .- 1873-3700. ; 41:6, s. 1477-1483
  • Tidskriftsartikel (refereegranskat)abstract
    • The floral fragrance of the shrub Daphne mezereum in central Sweden was collected by means of the head-space technique and investigated by GC-MS and multi-dimensional GC. (S)-(+)-Linalool was the main constituent (95%) of the flower fragrance and its enantiomeric purity exceeded 99% in the samples. The (2S, 5S)- and (2R, 5S)-furanoid and the (3R, 6S)- and (3S, 6S)-pyranoid linalool oxide isomers constituted 2-5% of the fragrance. The elution order of these compounds on a permethylated beta-cyclodextrin column is reported. A fragrance sample of D. mezereum as well as (S)-(+)-linalool attracted males of the vernal solitary bee species Colletes cunicalarius and Andrena cinerea. A racemic mixture of the two enantiomeric pairs of known furanoid linalool oxides was only weakly attractive to the bees. The role of the fragrance in the pollination specialization of the plant is discussed.
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11.
  • Borg, Rikard, et al. (författare)
  • Modeling of delamination using a discretized cohesive zone and damage formulation
  • 2002
  • Ingår i: Composites Science And Technology. - 0266-3538 .- 1879-1050. ; 62:10-11, s. 1299-1314
  • Tidskriftsartikel (refereegranskat)abstract
    • Delamination initiation and growth are analyzed by using a discrete cohesive crack model. The delamination is constrained to grow along a tied interface. The model is derived by postulating the existence of a maximum load surface which limits the adhesive forces in the process zone of the crack. The size of this maximum load surface is made dependent on the amount of dissipated crack opening work, such that the maximum load surface shrinks to zero as a predefined amount of work is consumed. A damage formulation is used to reduce the adhesive forces. Mode I, II and III loading or any combined loading is possible. An analytical solution is obtained for a single mode opening and the implications of this result on the governing equations is discussed. The delamination model is implemented in the finite element code LS-DYNA and simulation results are shown to be in agreement with experimental results. © 2002 Elsevier Science Ltd. All rights reserved.
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12.
  • Borg, Rikard, 1962-, et al. (författare)
  • Simulating DCB, ENF and MMB experiments using shell elements and a cohesive zone model
  • 2004
  • Ingår i: Composites Science And Technology. - 0266-3538 .- 1879-1050. ; 64:2, s. 269-278
  • Tidskriftsartikel (refereegranskat)abstract
    • A delamination model for shell elements is presented. It consists of an adhesive penalty contact formulation for initially tying shells together and a cohesive zone model for degrading the adhesive forces. An adhesive contact used between shell elements has to account for the thickness offset, such that the rotational degrees of freedom in the shell elements are included in the algorithm. This is considered in the present contact model and the complete delamination model is implemented in the explicit Finite Element code LS-DYNA. By preventing delamination growth the delamination model can be turned into a tied contact. As such it is used in two FE-models, where plates are bonded together and subjected to various loads. The adhesive penalty contact performs well. The complete delamination is validated by simulating the Double Cantilever Beam, End-Notch Flexural and Mixed Mode Bending setups, and the results are shown to be in agreement with experimental data.
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13.
  • Borg, Rikard, 1962-, et al. (författare)
  • Simulation of delamination in fiber composites with a discrete cohesive failure model
  • 2001
  • Ingår i: Composites Science And Technology. - 0266-3538 .- 1879-1050. ; 61:5
  • Annan publikation (populärvet., debatt m.m.)abstract
    • Delamination initiation and growth are analyzed by using a discrete cohesive crack model. The model is derived by postulating the existence of a maximum load surface which limits the adhesive forces in the process zone of the crack. The size of the maximum load surface is made dependent on the amount of dissipated crack opening work such that the maximum load surface shrinks to zero as a predefined amount of work is consumed. Mode I, II, III loading or any combined loading is possible. The delamination model is implemented in the explicit finite-element code LS-DYNA and simulation results are found to be in agreement with experimental results. ⌐ 2001 Elsevier Science Ltd. All rights reserved.
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14.
  • Borg, Rikard, 1962-, et al. (författare)
  • Simulation of low velocity impact on fiber laminates using a cohesive zone based delamination model
  • 2004
  • Ingår i: Composites Science And Technology. - 0266-3538 .- 1879-1050. ; 64:2, s. 279-288
  • Tidskriftsartikel (refereegranskat)abstract
    • An existing delamination model is further developed for use in transverse impact simulations. An algorithm is developed making it possible to determine the propagation direction of the delamination front. Using this it is possible to determine relative orientation of the delamination front with respect to the fibers above and below the interface. In a qualitative evaluation it is shown that the present delamination model can be used for modeling delamination initiation and growth in transverse impact simulations.
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15.
  • Chaplin, John, et al. (författare)
  • Translation and cross-cultural adaptation of ten pediatric PROMIS (R) item banks into Swedish
  • 2020
  • Ingår i: Quality of Life Research. - : Springer. - 0962-9343 .- 1573-2649. ; 29:Suppl. 1, s. S175-S176
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Aims: We describe the first large-scale translation and cross-cultural adaptation into Swedish of ten pediatric PROMIS item banks: Anger (9-items), Anxiety (15-items), Depressive symptoms (14-items) ,Cognitive function (43-items), Family relationships (47-items), Fatigue (25-items), Pain interference (20-items), Peer relationships (15-items), Physical activity (10-items), Positive affect (38-items) and Profile-25.Methods: ISPOR recommendations were followed. There view was carried out in multi-professional small groups of twelve health-related quality-of-life researchers, pediatric clinicians and linguists from different geographical regions in a two-day workshop. Cross-cultural comparisons were made to identify problems and to produce a consensus-derived version, which was then back translated, evaluated, and revised where necessary. Prior translations and review of version 1 of the item-banks were utilized (4 item-banks). There viewed item-banks were presented in four sessions of cognitive debriefings over 2 years with twenty-two young people (8-18 years) in three dialectically different regions of Sweden before finalization.Results: One hundred and seventy-five items were translated. All item banks had translation issues to be resolved. Sixty-six items (38%) needed resolution at the cognitive debriefing stage, the majority of issues were in the area of unclear definitions in the English items (35 items), followed by language and cultural differences (16 issues) and age appropriate language (14 items). The cultural issues identified were 1) identifying suitable word alternative to match the English where Swedish lacked the volume of words to choose from; 2) adjectival agreement on intensity levels of the concept to be translated; 3) culturally specific idiomatic phrases; 4) use of linguistically specific homonyms in English that did not match Swedish word usage; 5) cultural differences in describing members of the family unit and the family unit itself.Conclusion: The Swedish translations of ten PROMIS Pediatric item banks and Profile-25 were rigorously translated using internationally standardized methods. Close consideration of the translations, and multiple translations helped to ensure conceptual equivalence and comprehensibility. The banks are culturally adapted and appropriate for the age range 8 to 18 years. They can be used for clinical trials and routine pediatric health care.
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18.
  • Eriksson, Cecilia, et al. (författare)
  • Microfluidic analysis of antibody specificity in a compact disk format
  • 2006
  • Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 5:7, s. 1568-1574
  • Tidskriftsartikel (refereegranskat)abstract
    • A new and flexible technology for high throughput analysis of antibody specificity and affinity is presented. The method is based on microfluidics and takes advantage of compact disks (CDs) in which the centrifugal force moves fluids through microstructures containing immobilized metal affinity chromatography columns. Analyses are performed as a sandwich assay, where antigen is captured to the column via a genetically attached His(6)-tag. The antibodies to be analyzed are applied onto the columns. Thereafter, fluorescently labeled secondary antibodies recognize the bound primary antibodies, and detection is carried out by laser-induced fluorescence. The CDs contain 104 microstructures enabling analysis of antibodies against more than 100 different proteins using a single CD. Importantly, through the three- dimensional visualization of the binding patterns in a column it is possible to separate high affinity from low affinity binding. The method presented here is shown to be very sensitive, flexible and reproducible.
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19.
  • Ge, Changrong P, et al. (författare)
  • Anti-citrullinated protein antibodies cause arthritis by cross-reactivity to joint cartilage
  • 2017
  • Ingår i: JCI INSIGHT. - : AMER SOC CLINICAL INVESTIGATION INC. - 2379-3708. ; 2:13
  • Tidskriftsartikel (refereegranskat)abstract
    • Today, it is known that autoimmune diseases start a long time before clinical symptoms appear. Anti-citrullinated protein antibodies (ACPAs) appear many years before the clinical onset of rheumatoid arthritis (RA). However, it is still unclear if and how ACPAs are arthritogenic. To better understand the molecular basis of pathogenicity of ACPAs, we investigated autoantibodies reactive against the C1 epitope of collagen type II (CII) and its citrullinated variants. We found that these antibodies are commonly occurring in RA. A mAb (ACC1) against citrullinated C1 was found to cross-react with several noncitrullinated epitopes on native CII, causing proteoglycan depletion of cartilage and severe arthritis in mice. Structural studies by X-ray crystallography showed that such recognition is governed by a shared structural motif "RG-TG" within all the epitopes, including electrostatic potential-controlled citrulline specificity. Overall, we have demonstrated a molecular mechanism that explains how ACPAs trigger arthritis.
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20.
  • Ge, Changrong, et al. (författare)
  • Structural Basis of Cross-Reactivity of Anti-Citrullinated Protein Antibodies
  • 2019
  • Ingår i: Arthritis & Rheumatology. - : WILEY. - 2326-5191 .- 2326-5205. ; 71:2, s. 210-221
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective Anti-citrullinated protein antibodies (ACPAs) develop many years before the clinical onset of rheumatoid arthritis (RA). This study was undertaken to address the molecular basis of the specificity and cross-reactivity of ACPAs from patients with RA. Methods Antibodies isolated from RA patients were expressed as monoclonal chimeric antibodies with mouse Fc. These antibodies were characterized for glycosylation using mass spectrometry, and their cross-reactivity was assessed using Biacore and Luminex immunoassays. The crystal structures of the antigen-binding fragment (Fab) of the monoclonal ACPA E4 in complex with 3 different citrullinated peptides were determined using x-ray crystallography. The prevalence of autoantibodies reactive against 3 of the citrullinated peptides that also interacted with E4 was investigated by Luminex immunoassay in 2 Swedish cohorts of RA patients. Results Analysis of the crystal structures of a monoclonal ACPA from human RA serum in complex with citrullinated peptides revealed key residues of several complementarity-determining regions that recognized the citrulline as well as the neighboring peptide backbone, but with limited contact with the side chains of the peptides. The same citrullinated peptides were recognized by high titers of serum autoantibodies in 2 large cohorts of RA patients. Conclusion These data show, for the first time, how ACPAs derived from human RA serum recognize citrulline. The specific citrulline recognition and backbone-mediated interactions provide a structural explanation for the promiscuous recognition of citrullinated peptides by RA-specific ACPAs.
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21.
  • Gennemark, Peter, et al. (författare)
  • An oral antisense oligonucleotide for PCSK9 inhibition
  • 2021
  • Ingår i: Science Translational Medicine. - : AMER ASSOC ADVANCEMENT SCIENCE. - 1946-6234 .- 1946-6242. ; 13:593
  • Tidskriftsartikel (refereegranskat)abstract
    • Inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9) reduce low-density lipoprotein (LDL) cholesterol and are used for treatment of dyslipidemia. Current PCSK9 inhibitors are administered via subcutaneous injection. We present a highly potent, chemically modified PCSK9 antisense oligonucleotide (ASO) with potential for oral delivery. Past attempts at oral delivery using earlier-generation ASO chemistries and transient permeation enhancers provided encouraging data, suggesting that improving potency of the ASO could make oral delivery a reality. The constrained ethyl chemistry and liver targeting enabled by N-acetylgalactosamine conjugation make this ASO highly potent. A single subcutaneous dose of 90 mg reduced PCSK9 by >90% in humans with elevated LDL cholesterol and a monthly subcutaneous dose of around 25 mg is predicted to reduce PCSK9 by 80% at steady state. To investigate the feasibility of oral administration, the ASO was coformulated in a tablet with sodium caprate as permeation enhancer. Repeated oral daily dosing in dogs resulted in a bioavailability of 7% in the liver (target organ), about fivefold greater than the plasma bioavailability. Target engagement after oral administration was confirmed by intrajejunal administration of a rat-specific surrogate ASO in solution with the enhancer to rats and by plasma PCSK9 and LDL cholesterol lowering in cynomolgus monkey after tablet administration. On the basis of an assumption of 5% liver bioavailability after oral administration in humans, a daily dose of 15 mg is predicted to reduce circulating PCSK9 by 80% at steady state, supporting the development of the compound for oral administration to treat dyslipidemia.
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22.
  • Gosztonyi, Susanne, et al. (författare)
  • Multi-active façade for refurbishments of residential buildings
  • 2016
  • Ingår i: Journal of Façade Design and Engineering. - 2213-3038. ; 4:3
  • Tidskriftsartikel (refereegranskat)abstract
    • This article reflects results from the technology screening and analyses of passive and active measures applied to large scale residential building refurbishments, focusing on the facade. This work is part of the research study ‘multi-active façade' that focuses on the development of an innovative facade concept suitable for the refurbishment challenges that the ambitious Swedish housing programme "Miljonprogrammet" of the 1960s to 1970s is facing now. The objective is to identify those measures for energy efficient facade refurbishments of a building concept that uses multifunctional solutions, while an upgrading towards a highly energy efficient standard is economically limited. Two criteria are in the centre of the investigations: “Multi-active” and “prefabrication” in the realm of cost-effectiveness and minimal-invasive refurbishment. Hereby, "passive" measures, such as adaptive thermal insulation or thermal puffer zones useable as extended living areas, are analysed in the context of their performance effectiveness in cold climates. The potential of “active” measures, such as semi-decentralized ventilation or solar energy technologies, is analysed in regards to utilize existing infrastructure, decentralized functionality and local sources at its optimum. All measures shall provide a high comfort and performance out of the façade. The facade is also meant to be a “plug and play” system allowing fast mounting and high archi-tectural flexibility. Framing criteria are sustainability and - critical for the success of refurbishments – economic replicability. The benefits of such energy renovation, often not considered in the decision making process, shall become visible by life cycle assessments and performance analyses. The analyses in this article contributes to the ongoing process in these goals, drawing conclusions for the replicability of selected active and passive solutions.
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23.
  • Govik, Alexander, et al. (författare)
  • A study of the unloading behaviour of dual phase steel
  • 2014
  • Ingår i: Materials Science & Engineering. - : Elsevier. - 0921-5093 .- 1873-4936. ; 602, s. 119-126
  • Tidskriftsartikel (refereegranskat)abstract
    • It is important to understand the strain recovery of a steel sheet in order to predict its springback behaviour. During strain recovery, the stress–strain relation is non-linear and the resulting unloading modulus is decreased. Moreover, the unloading modulus will degrade with increasing plastic pre-straining. This study aims at adding new knowledge on these phenomena and the mechanisms causing them. The unloading behaviour of the dual-phase steel DP600 is characterised experimentally and finite element (FE) simulations of a representative volume element (RVE) of the microstructure are performed. The initial stress and strain state of the micromechanical FE model is found by a simplified simulation of the annealing processes. It is observed from the experimental characterisation that the decrease of the initial stiffness of the unloading is the main reason for the degrading unloading modulus. Furthermore, the developed micromechanical FE model exhibits non-linear strain recovery due to local plasticity caused by interaction between the two phases.
  •  
24.
  • Green, Rikard, et al. (författare)
  • Cross-Commodity News Transmission and Volatility Spillovers in the German Energy Markets
  • 2016
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • This study investigates volatility spillovers to electric power fromlarge exogenous shocks in the prices of gas, coal, and carbon emissionallowances in the German energy market. Our sample ranges from 2008 to 2016and covers periods of different market conditions. We use a general VAR-BEKKmodel and the volatility impulse response function methodology to analyze andevaluate the spillover effects. Special attention is paid to selecting anappropriate econometric volatility model. Our results show that the spillovereffects often are of a significant magnitude and display considerablevariation over time and across commodities. Coal and gas generatenon-negligible spillovers during almost the entire sample period. Carbon hasvery little impact during the early and late parts of the sample, butgenerates significant, and highly variable, spillovers during the period from2011 to the end of 2014.
  •  
25.
  • Green, Rikard, et al. (författare)
  • Cross-Commodity News Transmission and Volatility Spillovers in the German Energy Markets
  • 2018
  • Ingår i: Journal of Banking and Finance. - : Elsevier BV. - 0378-4266 .- 1872-6372. ; 95, s. 231-243
  • Tidskriftsartikel (refereegranskat)abstract
    • This study investigates volatility spillovers to electric power from large exogenous shocks in the prices of gas, coal, and carbon emission allowances in the German energy market. Our sample ranges from 2008 to 2016 and covers periods of different market conditions. We use a general VAR-BEKK model and the volatility impulse response function methodology to analyze and evaluate the spillover effects. Special attention is paid to selecting an appropriate econometric volatility model. Our results show that the spillover effects often are of a significant magnitude and display considerable variation over time and across commodities. Coal and gas generate non-negligible spillovers during almost the entire sample period. Carbon has very little impact during the early and late parts of the sample, but generates significant, and highly variable, spillovers during the period from 2011 to the end of 2014.
  •  
26.
  • Gunell, Herbert, et al. (författare)
  • Why an intrinsic magnetic field does not protect a planet against atmospheric escape
  • 2018
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 614
  • Tidskriftsartikel (refereegranskat)abstract
    • The presence or absence of a magnetic field determines the nature of how a planet interacts with the solar wind and what paths are available for atmospheric escape. Magnetospheres form both around magnetised planets, such as Earth, and unmagnetised planets, like Mars and Venus, but it has been suggested that magnetised planets are better protected against atmospheric loss. However, the observed mass escape rates from these three planets are similar (in the approximate (0.5–2) kg s−1 range), putting this latter hypothesis into question. Modelling the effects of a planetary magnetic field on the major atmospheric escape processes, we show that the escape rate can be higher for magnetised planets over a wide range of magnetisations due to escape of ions through the polar caps and cusps. Therefore, contrary to what has previously been believed, magnetisation is not a sufficient condition for protecting a planet from atmospheric loss. Estimates of the atmospheric escape rates from exoplanets must therefore address all escape processes and their dependence on the planet’s magnetisation.
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27.
  • Gunter, Marc J, et al. (författare)
  • Coffee drinking and mortality in 10 European countries : A multinational cohort study
  • 2017
  • Ingår i: Annals of Internal Medicine. - 0003-4819 .- 1539-3704. ; 167:4, s. 236-247
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The relationship between coffee consumption and mortality in diverse European populations with variable coffee preparation methods is unclear. Objective: To examine whether coffee consumption is associated with all-cause and cause-specific mortality. Design: Prospective cohort study. Setting: 10 European countries. Participants: 521 330 persons enrolled in EPIC (European Prospective Investigation into Cancer and Nutrition). Measurements: Hazard ratios (HRs) and 95% CIs estimated using multivariable Cox proportional hazards models. The association of coffee consumption with serum biomarkers of liver function, inflammation, and metabolic health was evaluated in the EPIC Biomarkers subcohort (n = 14 800). Results: During a mean follow-up of 16.4 years, 41 693 deaths occurred. Compared with nonconsumers, participants in the highest quartile of coffee consumption had statistically significantly lower all-cause mortality (men: HR, 0.88 [95% CI, 0.82 to 0.95]; P for trend < 0.001; women: HR, 0.93 [CI, 0.87 to 0.98]; P for trend = 0.009). Inverse associations were also observed for digestive disease mortality for men (HR, 0.41 [CI, 0.32 to 0.54]; P for trend < 0.001) and women (HR, 0.60 [CI, 0.46 to 0.78]; P for trend < 0.001). Among women, there was a statistically significant inverse association of coffee drinking with circulatory disease mortality (HR, 0.78 [CI, 0.68 to 0.90]; P for trend < 0.001) and cerebrovascular disease mortality (HR, 0.70 [CI, 0.55 to 0.90]; P for trend = 0.002) and a positive association with ovarian cancer mortality (HR, 1.31 [CI, 1.07 to 1.61]; P for trend = 0.015). In the EPIC Biomarkers subcohort, higher coffee consumption was associated with lower serum alkaline phosphatase; alanine aminotransferase; aspartate aminotransferase; 7-glutamyltransferase; and, in women, C-reactive protein, lipoprotein(a), and glycated hemoglobin levels. Limitations: Reverse causality may have biased the findings; however, results did not differ after exclusion of participants who died within 8 years of baseline. Coffee-drinking habits were assessed only once. Conclusion: Coffee drinking was associated with reduced risk for death from various causes. This relationship did not vary by country.
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28.
  • Hallgren, Pär, et al. (författare)
  • Measuring bioavailability of polychlorinated biphenyls in soil to earthworms using selective supercritical fluid extraction
  • 2006
  • Ingår i: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 63:9, s. 1532-1538
  • Tidskriftsartikel (refereegranskat)abstract
    • If the release mechanisms during selective chemical extraction of persistent organic pollutants (POP) mimic release mechanisms in natural systems during biological uptake, then a selective non-exhaustive extraction could give a quantitative measure of the bioavailable POP fraction. Supercritical fluid extraction (SFE) is suggested as a possible technique to estimate the amount of bioavailable polychlorinated biphenyls (PCBs) at contaminated sites and hence serve as a new tool in risk assessment. The uptake of PCBs by earthworm (Eisenia foetida) was investigated. PCB contaminated soil was pre-extracted with selective non-exhaustive SFE (50 degrees C, 350 bar, 1 h), which removed on average 70% of the individual PCBs. Earthworms were placed in this pre-extracted soil, as well as in untreated soil. After 10 days, the PCB uptake by earthworms in the two systems was compared. The bioaccumulation factor(BAF) was 83% lower in the pre-extracted system than in the untreated system, demonstrating that SFE extracts primarily bioavailable contaminants. From the data, the bioavailable fraction could also be calculated to be 75%, which is very close to the 70% removed by SFE under the applied conditions. This suggests that the chemical methodology is capable of measuring the bioavailable fraction very accurately in this system. (c) 2005 Elsevier Ltd. All rights reserved.
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29.
  • Hansen, Bjarne H, et al. (författare)
  • The Scandinavian Sarcoma Group Skeletal Metastasis Registry Functional outcome and pain after surgery for bone metastases in the pelvis and extremities
  • 2009
  • Ingår i: ACTA ORTHOPAEDICA. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 80, s. 85-90
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Few authors have investigated function and pain after surgical treatment of patients with bone metastases. In 1999 the Scandinavian Sarcoma Group (SSG) initiated the Skeletal Metastasis Registry as a multi-centric, prospective study to provide a scientific basis for recommendations of treatment. Patients and methods We have analyzed function and pain in 530 patients (mean age 65 yr) operated on (599 operations) for non-spinal skeletal metastases at 9 SSG centres. 7% were operated for more than 1 metastasis. Carcinoma of the breast, prostate, kidney, and lung were the dominating sites for primary tumors. Results 25% of the patients died within 6 weeks after operation. 11% of the patients had complications. 6% had reoperation. In patients surviving more than 1 year the reoperation rate was 12%. 92% of the patients had no, light or moderate pain from metastasis at 6 weeks (first control) and 6 months follow-up. Patients using opioids were reduced from 40% preoperative to 30% at 6 months after surgery. In patients with metastases in pelvis or lower extremity 79% were walking with or without crutches, 6 weeks and 88%, 6 months after surgery. More patients with metastases; in proximal femur were mobile at 6 weeks and 6 months when treated with prosthetic replacement compared to internal fixation. Interpretation Palliative surgery for bone metastases improves function and reduce pain. Mobility is improved by surgery in patients with metastases in the pelvis or lower extremity. Prosthetic replacement seems to do better than internal fixation for metastases in the proximal femur. We need to analyze function and pain earlier than 6 weeks postoperative to investigate the benefit of surgery in patients with short time survival.
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30.
  • Johnsen, Nina F., et al. (författare)
  • Whole-grain products and whole-grain types are associated with lower all-cause and cause-specific mortality in the Scandinavian HELGA cohort
  • 2015
  • Ingår i: British Journal of Nutrition. - 0007-1145 .- 1475-2662. ; 114:4, s. 608-623
  • Tidskriftsartikel (refereegranskat)abstract
    • No study has yet investigated the intake of different types of whole grain (WG) in relation to all-cause and cause-specific mortality in a healthy population. The aim of the present study was to investigate the intake of WG products and WG types in relation to all-cause and cause-specific mortality in a large Scandinavian HELGA cohort that, in 1992-8, included 120 010 cohort members aged 30-64 years from the Norwegian Women and Cancer Study, the Northern Sweden Health and Disease Study, and the Danish Diet Cancer and Health Study. Participants filled in a FFQ from which data on the intake of WG products were extracted. The estimation of daily intake of WG cereal types was based on country-specific products and recipes. Mortality rate ratios (MRR) and 95% CI were estimated using the Cox proportional hazards model. A total of 3658 women and 4181 men died during the follow-up (end of follow-up was 15 April 2008 in the Danish sub-cohort, 15 December 2009 in the Norwegian sub-cohort and 15 February 2009 in the Swedish sub-cohort). In the analyses of continuous WG variables, we found lower all-cause mortality with higher intake of total WG products (women: MRR 0.89 (95% CI 0.86, 0.91); men: MRR 0.89 (95% CI 0.86, 0.91) for a doubling of intake). In particular, intake of breakfast cereals and non-white bread was associated with lower mortality. We also found lower all-cause mortality with total intake of different WG types (women: MRR 0.88 (95% CI 0.86, 0.92); men: MRR 0.88 (95% CI 0.86, 0.91) for a doubling of intake). In particular, WG oat, rye and wheat were associated with lower mortality. The associations were found in both women and men and for different causes of deaths. In the analyses of quartiles of WG intake in relation to all-cause mortality, we found lower mortality in the highest quartile compared with the lowest for breakfast cereals, non-white bread, total WG products, oat, rye (only men), wheat and total WG types. The MRR for highest v. lowest quartile of intake of total WG products was 0.68 (95% CI 0.62, 0.75, P-trend over quartiles, 0.0001) for women and 0.75 (95% CI 0.68, 0.81, P-trend over quartiles, 0.0001) for men. The MRR for highest v. lowest quartile of intake of total WG types was 0.74 (95% CI 0.67, 0.81, P-trend over quartiles, 0.0001) for women and 0.75 (95% CI 0.68, 0.82, P-trend (over quartiles), 0.0001) for men. Despite lower statistical power, the analyses of cause-specific mortality according to quartiles of WG intake supported these results. In conclusion, higher intake of WG products and WG types was associated with lower mortality among participants in the HELGA cohort. The study indicates that intake of WG is an important aspect of diet in preventing early death in Scandinavia.
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31.
  • Knudsen, Markus Dines, et al. (författare)
  • Self-Reported Whole-Grain Intake and Plasma Alkylresorcinol Concentrations in Combination in Relation to the Incidence of Colorectal Cancer
  • 2014
  • Ingår i: American Journal of Epidemiology. - : Oxford University Press. - 0002-9262 .- 1476-6256. ; 179:10, s. 1188-1196
  • Tidskriftsartikel (refereegranskat)abstract
    • Self-reported food frequency questionnaires (FFQs) have occasionally been used to investigate the association between whole-grain intake and the incidence of colorectal cancer, but the results from those studies have been inconsistent. We investigated this association using intakes of whole grains and whole-grain products measured via FFQs and plasma alkylresorcinol concentrations, a biomarker of whole-grain wheat and rye intake, both separately and in combination (Howe's score with ranks). We conducted a nested case-control study in a cohort from a research project on Nordic health and whole-grain consumption (HELGA, 1992-1998). Incidence rate ratios and 95% confidence intervals were calculated using conditional logistic regression. Plasma alkylresorcinol concentrations alone and Howe's score with ranks were inversely associated with the incidence of distal colon cancer when the highest quartile was compared with the lowest (for alkylresorcinol concentrations, incidence rate ratio = 0.34, 95% confidence interval: 0.13, 0.92; for Howe's score with ranks, incidence rate ratio = 0.35, 95% confidence interval: 0.15, 0.86). No association was observed between whole-grain intake and any colorectal cancer (colon, proximal, distal or rectum cancer) when using an FFQ as the measure/exposure variable for whole-grain intake. The results suggest that assessing whole-grain intake using a combination of FFQs and biomarkers slightly increases the precision in estimating the risk of colon or rectal cancer by reducing the impact of misclassification, thereby increasing the statistical power of the study.
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32.
  • Kyrø, Cecilie, et al. (författare)
  • Intake of whole grains from different cereal and food sources and incidence of colorectal cancer in the Scandinavian HELGA cohort
  • 2013
  • Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 0957-5243 .- 1573-7225. ; 24:7, s. 1363-1374
  • Tidskriftsartikel (refereegranskat)abstract
    • A high intake of whole grains has been associated with a lower incidence of colorectal cancer, but few studies are available on the association with whole grains from different cereals, for example, wheat, rye and oats, and none has addressed these separately. The objective of this study was to investigate the association between whole-grain intake and colorectal cancer. We used data from the large population-based Scandinavian cohort HELGA consisting of 108,000 Danish, Swedish, and Norwegian persons, of whom 1,123 developed colorectal cancer during a median of 11 years of follow-up. Detailed information on daily intake of whole-grain products, including whole-grain bread, crispbread, and breakfast cereals, was available, and intakes of total whole grains and specific whole-grain species (wheat, rye, and oats) were estimated. Associations between these whole-grain variables and the incidence of colorectal cancer were investigated using Cox proportional hazards models. Intake of whole-grain products was associated with a lower incidence of colorectal cancer per 50-g increment (incidence rate ratio [IRR], 0.94; 95 % confidence interval [CI], 0.89, 0.99), and the same tendency was found for total whole-grain intake (IRR pr. 25-g increment, 0.94; 95 % CI, 0.88, 1.01). Intake of whole-grain wheat was associated with a lower incidence of colorectal cancer (IRR for highest versus lowest quartile of intake, 0.66; 95 % CI, 0.51, 0.85), but no statistical significant linear trend was observed (p for trend: 0.18). No significant association was found for whole-grain rye or oats. Whole-grain intake was associated with a lower incidence of colorectal cancer.
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33.
  • Larsson, Rikard, 1982-, et al. (författare)
  • A study of high strength steels undergoing non-linear strain paths—Experiments and modelling
  • 2011
  • Ingår i: Journal of Materials Processing Technology. - : Elsevier. - 0924-0136 .- 1873-4774. ; 211:1, s. 121-131
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents an evaluation of the constitutive behaviour, including plastic anisotropy and mixed isotropic-kinematic hardening of two high strength steels, Docol 600DP and Docol 1200M, during strain path changes. A series of tensile and shear tests was performed on both virgin and pre-strained materials. The initial anisotropy and work hardening parameters were obtained from tensile tests, shear tests and a bulge test of the virgin material, whereas the kinematic hardening parameters were identified by comparing numerical predictions to experimental results related to the pre-strained materials. Numerical predictions using the obtained parameters agree well with the experimental results, both in the case of proportional, and under non-proportional strain paths.
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34.
  • Larsson, Rikard (författare)
  • Improved Material Models for High Strength Steel
  • 2011
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The mechanical behaviour of the three advanced high strength steel grades, Docol 600DP, Docol 1200M and HyTens 1000, has been experimentally investigated under various types of deformation, and material models have been developed, which account for the experimentally observed behaviour.Two extensive experimental programmes have been conducted in this work. In the first, the dual phase Docol 600DP steel and martensitic Docol 1200M steel were subjected to deformations both under linear and non-linear strain paths. Regular test specimens were made both from virgin materials, i.e. as received, and from materials pre-strained in various directions. The plastic strain hardening, as well as plastic anisotropy and its evolution during deformation of the two materials, were evaluated and modelled with a phenomenological model.In the second experimental program, the austenitic stainless HyTens 1000 steel was subjected to deformations under various proportional strain paths and strain rates. It was shown experimentally that the material is sensitive both to dynamic and static strain ageing. A phenomenological model accounting for these effects was developed, calibrated, implemented in a Finite Element software and, finally,validated.Both direct methods and inverse analyses were used in order to calibrate the parameters in the material models. The agreement between the  numerical and experimental results are in general very good.This thesis is divided into two main parts. The background, theoretical framework and mechanical experiments are presented in the rst part. In the second part, two papers are appended.
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35.
  • Larsson, Rikard, et al. (författare)
  • On isotropic-distortional hardening
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Isotropic-distortional hardening allows for individual stress-plastic strain relations in different straining directions. Such hardening can be obtained by allowing the parameters in the effective stress function to depend on anisotropy functions of the equivalent plastic strain. A methodology to calibrate these anisotropy functions is proposed in this work, and is demonstrated on an austenitic strainless steel. A high exponent eight parameter effective stress function for plane stress states is utilised. The anisotropy functions are calibrated by the use of experimental data from uniaxial tensile test data in three material directions and a balanced biaxial test. The plastic anisotropy is assumed to vary piecewise linearly with respect to the equivalent plastic strain, and it is evaluated at a finite number of plastic strains. Thus, it is correctly represented at each level of plastic strain included in the evaluation, even if large increments in plastic strain are used in the calibration. It was found that there are at least two sets of anisotropy functions which satisfy the conditions in the calibration procedure. The resulting uniaxial stress-strain relations from the two sets of anisotropy functions in four additional straining directions, not included in the calibration set, were compared to the corresponding experimental data. From this validation, one of the anisotropy function sets could be discarded, whereas the other one gave a good prediction of the stress-strain relations in all the four additional directions.
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36.
  • Larsson, Rikard, 1982- (författare)
  • On Material Modelling of High Strength Steel Sheets
  • 2012
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The work done in this thesis aims at developing and improving material models for use in industrial applications.The mechanical behaviour of three advanced high strength steel grades, Docol 600DP, Docol 1200M and HyTens 1000, has been experimentally investigated under various types of deformation, and material models of their behaviour have been developed. The origins of all these material models are experimental findings from physical tests on the materials.Sheet metal forming is an important industrial process and is used to produce a wide range of products. The continuously increasing demand on the weight to performance ratio of many products promotes the use of advanced high strength steel. In order to take full advantage of such steel, most product development is done by means of computer aided engineering, CAE. In advanced product development, the use of simulation based design, SBD, is continuously increasing. With SBD, the functionality of a product, as well as its manufacturing process, can be analysed and optimised with a minimum of physical prototype testing. Accurate numerical tools are absolutely necessary with this methodology, and the model of the material behaviour is one important aspect of such tools.This thesis consists of an introduction followed by five appended papers. In the first paper, the dual phase Docol 600DP steel and the martensitic Docol 1200M steel were subjected to deformations, both under linear and non-linear strain paths. Plastic anisotropy and hardening were evaluated and modelled using both virgin materials, i.e. as received, and materials which were pre-strained in various material directions.In the second paper, the austenitic stainless steel HyTens 1000 was subjected to deformations under various proportional strain paths and strain rates. It was experimentally shown that this material is sensitive both to dynamic and static strain ageing. A constitutive model accounting for these effects was developed, calibrated, implemented in a Finite Element software and, finally, validated on physical test data.The third paper concerns the material dispersions in batches of Docol 600DP. A material model was calibrated to a number of material batches of the same steel grade. The paper provides a statistical analysis of the resulting material parameters.The fourth paper deals with a simple modelling of distortional hardening. This type of hardening is able to represent the variation of plastic anisotropy during deformation. This is not the case with a regular isotropic hardening, where the anisotropy is fixed during deformation.The strain rate effect is an important phenomenon, which often needs to be considered in a material model. In the fifth paper, the strain rate effects in Docol 600DP are investigated and modelled. Furthermore, the strain rate effect on strain localisation is discussed.
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37.
  • Larsson, Rikard, et al. (författare)
  • On the modelling of strain ageing in a metastable austenitic stainless steel
  • 2012
  • Ingår i: Journal of Materials Processing Technology. - : Elsevier. - 0924-0136 .- 1873-4774. ; 212:1, s. 46-58
  • Tidskriftsartikel (refereegranskat)abstract
    • The plastic hardening of metastable austenitic stainless steel is partly governed by martensitic transformation, the occurrence of serrated plastic flow, and plastic strain ageing phenomena. In this paper an elasto-viscoplastic material model with isotropic distortional plastic hardening is developed. The model accounts for static and dynamic strain ageing as well as the martensitic transformation. An experimental programme has been conducted in order to fit the model parameters to an austenitic stainless steel within the EN 1.4310 standard. The identification of the dynamic strain ageing was based on so called jump tests, where a sudden strain rate increase was shown to result in an instantaneous positive strain rate sensitivity followed by negative steady state strain rate sensitivity. Furthermore, the static strain ageing was identified by unloading tensile test specimens at specified plastic strains and then reloading these specimens after different periods of time. The observed material behaviour in the test situations can be predicted by the developed model. Lastly, the model was validated by predicting the force-displacement relation of the material in a shear test: the prediction agrees well with experimental results.
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38.
  • Larsson, Rikard, et al. (författare)
  • Strain rate effects in a high strength dual phase steel
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • This work focuses on strain rate effects in a high strength dual phase steel, DP600. Attention is given to the mathematical formulation of the strain rate sensitivity, and to its influence on the strain at localisation. Both an experimental and a numerical study are presented. In the experimental study, uniaxial and notched tensile tests, as well as shear tests were conducted at various loading rates. Furthermore, strain rate jump tests were conducted in order to further investigate the strain rate sensitivity. It is clearly shown that the material has a positive strain rate sensitivity, and that a multiplicative contribution to the flow stress is a better approximation than an additive one. A material model including a non-linear plastic hardening, a high exponent yield surface, a thermal softening effect and a variety of multiplicative strain rate sensitivity functions is presented and calibrated. This material model is used in finite element simulations of the mechanical tests. The predicted results are in good agreement with the experimental findings. The stabilising effect of the strain rate sensitivity is shown to be important whenever strain localisation becomes an issue in finite element simulations. It is also shown that the strain rate sensitivity index depends on the plastic strain rate, which thus is the case also for the stabilising effect. From a supplementary study, it is concluded that the assumed thermal softening will affect the onset of localisation.
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39.
  • Lu, Zhonghai, et al. (författare)
  • NNSE: Nostrum Network-on-Chip Simulation Environment
  • 2005
  • Ingår i: Proceedings of Swedish System-on-Chip Conference, Stockholm, Sweden, April 2005..
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • A main challenge for Network-on-Chip (NoC) design isto select a network architecture that suits a particular application.NNSE enables to analyze the performance impactof NoC configuration parameters. It allows one to(1) configure a network with respect to topology, flow controland routing algorithm etc.; (2) configure various regularand application specific traffic patterns; (3) evaluatethe network with the traffic patterns in terms of latency and throughput.
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40.
  • Magnusson, Johan, 1976, et al. (författare)
  • Toward a new Theory of the Firm: Warrant, Design and Proposal
  • 2018
  • Ingår i: Blockchain Technology & Organizations Research Symposium at the University of Connecticut.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In this paper, we posit that blockchain technology and its application challenge the foundations of existing theories of the firm. Utilizing transaction cost economics as a point of reference, we explore how said theory grows obsolete with increasing blockchain adoption and how new theory is needed. At the core of our argument lies the diminution of transaction costs and its effect on the principles of scarcity, boundaries, motivation, size and returns. The paper identifies propositions where blockchain challenges the prevailing theory of the firm. These propositions are used as design criteria for future research agenda intended to contribute toward a new theory of the firm. Four design experiments utilizing application of blockchain are presented as a suggestion for future research.
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41.
  • Malmsten Lundgren, Victor, 1989-, et al. (författare)
  • Will There Be New Communication Needs When Introducing Automated Vehicles to the Urban Context?
  • 2017
  • Ingår i: Advances in Intelligent Systems and Computing. - Cham : Springer International Publishing. - 9783319416816 - 9783319416823 ; , s. 485-497
  • Konferensbidrag (refereegranskat)abstract
    • In today’s encounters with vehicles, pedestrians are often dependent on cues in drivers’ behavior such as eye contact, postures, and gestures. With an increased level of automation, and the transfer of control from the driver to the vehicle, the pedestrians cannot rely on such cues anymore. The question is: will there be new communication needs to warrant safe interactions with automated vehicles? This question is addressed by exploring pedestrians’ willingness to cross the street and their emotional state in encounters with a seemingly automated vehicle. The results show that pedestrians’ willingness to cross the street decrease with an inattentive driver. Eye contact with the driver on the other hand leads to calm interaction between vehicle and pedestrian. In conclusion, to sustain perceived safety when eye contact is discarded due to vehicle automation, it could be beneficial to provide pedestrians with the corresponding information in some other way (e.g., by means of an external vehicle interface).
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42.
  • Martínez-Ávila, Carlos, et al. (författare)
  • An exploratory study of the practice of stakeholder participation in densification projects
  • 2016
  • Ingår i: ; , s. 1-13
  • Konferensbidrag (refereegranskat)abstract
    • We report on the study of six similar buildings built in an area of Gothenburg, Sweden,in 1971, which are now in urgent need of renovation. However, the owner of thebuildings - a municipal housing company did not achieve a financially viablerenovation of the pilot project. This meant that renovation on a similar basis for theremaining five buildings would not be possible. For this reason the housing companychose to undertake a vertical extension, by adding two floors with apartments on topof the existing buildings. This has improved the economics and made renovation ofthe five buildings possible. The objectives of this study are therefore, to show how avertical extension can make a renovation of these buildings financially viable. Weargue that a vertical extension can be applied to other similar buildings from this era.If vertical extensions could make more renovations possible this would lead to asignificant impact on final energy use and carbon emissions. This case study has beensupported by a site visit, interviews with the housing company and the contractor,document analysis, energy simulation and global warming potential simulation. Fourrenovation concepts are compared in order to find the most appropriate: minimalist,code-compliant, low-energy and low-energy plus vertical extension renovation. Theconclusion of this study is that vertical extensions provide enough incentive to preformextensive energy renovations, which could reduce final energy use by more than 50%.
  •  
43.
  • Millberg, Mikael, et al. (författare)
  • Guaranteed bandwidth using looped containers in temporally disjoint networks within the Nostrum network on chip
  • 2004
  • Ingår i: Design, Automation And Test In Europe Conference And Exhibition, Vols 1 And 2, Proceedings. - LOS ALAMITOS, USA : IEEE COMPUTER SOC. - 0769520855 ; , s. 890-895
  • Konferensbidrag (refereegranskat)abstract
    • In today's emerging Network-on-Chips, there is a need for different traffic classes with different Quality-of-Service guarantees. Within our NoC architecture Nostrum, we have implemented a service of Guaranteed Bandwidth (GB), and latency, in addition to the already existing service of Best-Effort (BE) packet delivery. The guaranteed bandwidth is accessed via Virtual Circuits (VC). The vcs are implemented using a combination of two concepts that we call 'Looped Containers' and 'Temporally Disjoint Networks'. The Looped Containers are used to guarantee access to the network - independently of the current network load without dropping packets; and the TDNS are used in order to achieve several VCs, plus ordinary BE traffic, in the network. The TDNS are a consequence of the deflective routing policy used, and gives rise to an explicit time-division-multiplexing within the network. To prove our concept an HDL implementation has been synthesised and simulated. The cost in terms of additional hardware needed, as well as additional bandwidth is very low - less than 2 percent in both cases! Simulations showed that ordinary BE traffic is practically unaffected by the VCs.
  •  
44.
  • Millberg, Mikael, et al. (författare)
  • The Nostrum Backbone : a Communication Protocol Stack for Networks Chip
  • 2004
  • Ingår i: 17th International Conference On Vlsi Design, Proceedings - Design Methodologies For The Gigascale Era. - LOS ALAMITOS, USA : IEEE COMPUTER SOC. - 0769520723 ; , s. 693-696
  • Konferensbidrag (refereegranskat)abstract
    • We propose a communication protocol stack to be used in Nostrum, our Network on Chip (NoC) architecture. In order to aid the designer in the selection process of what parts of protocols, and their respective facilities, to include, a layered approach to communication is taken. A nomenclature for describing the individual layers' interfaces and service definitions of the layers in the protocol stack is suggested,and used. The concept includes support for best effort traffic packet delivery as well as support for guaranteed bandwidth traffic, using virtual circuits. Furthermore an application to NoC adapter is defined, as part of the Resource to Network Interface, and is used to communicate between the Nostrum protocol stack and the application. An industrial example has been implemented, simulated, and the results justifies the suggested layered approach.
  •  
45.
  • Montiel Rojas, Diego, 1984- (författare)
  • Diet and sarcopenia risk in community-dwelling older European adults
  • 2022
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The age-related decline in muscle strength and muscle mass can lead to sarcopenia with higher risk of falls, disability, and loss of independence. In this context, healthy dietary habits have the potential to delay onset of physical limitations, thereby promoting healthy ageing. The overall aim of the thesis was to investigate the role of dietary habits on indicators ofmuscle health in a sample of community-dwelling older European men and women. The studies were performed within the frame of the NU-AGE project, a multi-centre study aiming to determine the impact of dietary habits on age-related functional decline. Studies I-III were based on crosssectional analyses, whereas study IV was a randomised controlled trial (RCT). In summary, Study I highlighted the independent roles of dietary protein amount and quality for muscle health in older adults. A positive linear dose-response relationship existed between protein intake and muscle health, with increased intake of plant-based proteins to the detriment of animal-based proteins was associated with reduced sarcopenia risk. Study II revealed that increased poly-unsaturated fatty acids intake to the detriment of saturated fatty acids was associated with lower sarcopenia risk in older adults with a dietary protein intake below 1.1 g/kg of body weight. In Study III, beneficial links between dietary fibre intake and muscle mass were observed in older European adults. In Study IV, a one-year RCT promoting adherence to a Mediterranean-style diet did not result in significant changes in muscle strength or mass. In conclusion, the present dissertation emphasised the important potential of macronutrient amount and quality in the prevention of age-related loss of muscle strength and muscle mass. However, future experimental studies are warranted to clarify the impact of whole-diet approaches, such as the Mediterranean diet, on the maintenance of muscle health in older adults.
  •  
46.
  • Nilsson, Anders K., 1982, et al. (författare)
  • PSB33 protein sustains photosystem II in plant chloroplasts under UV-A light
  • 2020
  • Ingår i: Journal of Experimental Botany. - OXFORD ENGLAND : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 71:22, s. 7210-7223
  • Tidskriftsartikel (refereegranskat)abstract
    • Plants can quickly and dynamically respond to spectral and intensity variations of the incident light. These responses include activation of developmental processes, morphological changes, and photosynthetic acclimation that ensure optimal energy conversion and minimal photoinhibition. Plant adaptation and acclimation to environmental changes have been extensively studied, but many details surrounding these processes remain elusive. The photosystem II (PSII)-associated protein PSB33 plays a fundamental role in sustaining PSII as well as in the regulation of the light antenna in fluctuating light. We investigated how PSB33 knock-out Arabidopsis plants perform under different light qualities. psb33 plants displayed a reduction of 88% of total fresh weight compared to wild type plants when cultivated at the boundary of UV-A and blue light. The sensitivity towards UV-A light was associated with a lower abundance of PSII proteins, which reduces psb33 plants' capacity for photosynthesis. The UV-A phenotype was found to be linked to altered phytohormone status and changed thylakoid ultrastructure. Our results collectively show that PSB33 is involved in a UV-A light-mediated mechanism to maintain a functional PSII pool in the chloroplast.
  •  
47.
  •  
48.
  • Nilsson, Hans, et al. (författare)
  • Hot and cold ion outflow : Observations and implications for numerical models
  • 2013
  • Ingår i: Journal of Geophysical Research - Space Physics. - : John Wiley & Sons. - 2169-9380 .- 2169-9402. ; 118:1, s. 105-117
  • Tidskriftsartikel (refereegranskat)abstract
    • Cluster observations of oxygen ion outflow and low-frequency waves at high altitude above the polar cap and cold ion outflow in the lobes are used to determine ion heating rates and low-altitude boundary conditions suitable for use in numerical models of ion outflow. Using our results, it is possible to simultaneously reproduce observations of high-energy O+ ions in the high-altitude cusp and mantle and cold H+ ions in the magnetotail lobes. To put the Cluster data in a broader context, we first compare the average observed oxygen temperatures and parallel velocities in the high-altitude polar cap with the idealized cases of auroral (cusp) and polar wind (polar cap) ion outflow obtained from a model based on other data sets. A cyclotron resonance model using average observed electric field spectral densities as input fairly well reproduces the observed velocities and perpendicular temperatures of both hot O+ and cold H+, if we allow the fraction of the observed waves, which is efficient in heating the ions to increase with altitude and decrease toward the nightside. Suitable values for this fraction are discussed based on the results of the cyclotron resonance model. Low-altitude boundary conditions, ion heating rates, and centrifugal acceleration are presented in a format suitable as input for models aiming to reproduce the observations
  •  
49.
  • Nilsson, Hans, et al. (författare)
  • Hot and cold ion outflow : Spatial distribution of ion heating
  • 2012
  • Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 117
  • Tidskriftsartikel (refereegranskat)abstract
    • Ions apparently emanating from the same source, the ionospheric polar cap, can either end up as energized to keV energies in the high-altitude cusp/mantle, or appear as cold ions in the magnetotail lobes. We use Cluster observations of ions and wave electric fields to study the spatial variation of ion heating in the cusp/mantle and polar cap. The average flow direction in a simplified cylindrical coordinate system is used to show approximate average ion flight trajectories, and discuss the temperatures, fluxes and wave activity along some typical trajectories. It is found that it is suitable to distinguish between cusp, central and nightside polar cap ion outflow trajectories, though O+ heating is mainly a function of altitude. Furthermore we use typical cold ion parallel velocities and the observed average perpendicular drift to obtain average cold ion flight trajectories. The data show that the cusp is the main source of oxygen ion outflow, whereas a polar cap source would be consistent with our average outflow paths for cold ions observed in the lobes. A majority of the cusp O+ flux is sufficiently accelerated to escape into interplanetary space. A scenario with significant oxygen ion heating in regions with strong magnetosheath origin ion fluxes, cold proton plasma dominating at altitudes below about 8 RE in the polar cap, and most of the cusp oxygen outflow overcoming gravity and flowing out in the cusp and mantle is consistent with our observations.
  •  
50.
  • Nilsson, Hans, et al. (författare)
  • Oxygen ion response to proton bursty bulk flows
  • 2016
  • Ingår i: Journal of Geophysical Research - Space Physics. - : American Geophysical Union (AGU). - 2169-9380 .- 2169-9402. ; 121:8, s. 7535-7546
  • Tidskriftsartikel (refereegranskat)abstract
    • We have used Cluster spacecraft data from the years 2001 to 2005 to study how oxygen ions respond to bursty bulk flows (BBFs) as identified from proton data. We here define bursty bulk flows as periods of proton perpendicular velocities more than 100 km/s and a peak perpendicular velocity in the structure of more than 200 km/s, observed in a region with plasma beta above 1 in the near-Earth central tail region. We find that during proton BBFs only a minor increase in the O+ velocity is seen. The different behavior of the two ion species is further shown by statistics of H+ and O+ flow also outside BBFs: For perpendicular earthward velocities of H+ above about 100 km/s, the O+ perpendicular velocity is consistently lower, most commonly being a few tens of kilometers per second earthward. In summary, O+ ions in the plasma sheet experience less acceleration than H+ ions and are not fully frozen in to the magnetic field. Therefore, H+ and O+ motion is decoupled, and O+ ions have a slower earthward motion. This is particularly clear during BBFs. This may add further to the increased relative abundance of O+ ions in the plasma sheet during magnetic storms. The data indicate that O+ is typically less accelerated in association with plasma sheet X lines as compared to H+.
  •  
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