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- Bergquist, Maria, et al.
(författare)
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Comprehensive multiplexed protein quantitation delineates eosinophilic and neutrophilic experimental asthma
- 2014
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Ingår i: BMC Pulmonary Medicine. - : Springer Science and Business Media LLC. - 1471-2466. ; 14, s. 110-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Improvements in asthma diagnosis and management require deeper understanding of the heterogeneity of the complex airway inflammation. We hypothesise that differences in the two major inflammatory phenotypes of asthma; eosinophilic and neutrophilic asthma, will be reflected in the lung protein expression profile of murine asthma models and can be delineated using proteomics of bronchoalveolar lavage (BAL). Methods: BAL from mice challenged with ovalbumin (OVA/OVA) alone (standard model of asthma, here considered eosinophilic) or OVA in combination with endotoxin (OVA/LPS, model of neutrophilic asthma) was analysed using liquid chromatography coupled to high resolution mass spectrometry, and compared with steroid-treated animals and healthy controls. In addition, conventional inflammatory markers were analysed using multiplexed ELISA (Bio-Plex T assay). Multivariate statistics was performed on integrative proteomic fingerprints using principal component analysis. Proteomic data were complemented with lung mechanics and BAL cell counts. Results: Several of the analysed proteins displayed significant differences between the controls and either or both of the two models reflecting eosinophilic and neutrophilic asthma. Most of the proteins found with mass spectrometry analysis displayed a considerable increase in neutrophilic asthma compared with the other groups. Conversely, the larger number of the inflammatory markers analysed with Bio-Plex T analysis were found to be increased in the eosinophilic model. In addition, major inflammation markers were correlated to peripheral airway closure, while commonly used asthma biomarkers only reflect central inflammation. Conclusion: Our data suggest that the commercial markers we are currently relying on to diagnose asthma subtypes are not giving us comprehensive or specific enough information. The analysed protein profiles allowed to discriminate the two models and may add useful information for characterization of different asthma phenotypes.
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| 2. |
- Brolin, Karin, et al.
(författare)
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The importance of muscle tension on the outcome of impacts with a major vertical component
- 2008
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Ingår i: International Journal of Crashworthiness. - London : Taylor & Francis. - 1358-8265 .- 1754-2111. ; 13:5, s. 487-498
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis that muscle tension protects the spine from injuries in helicopter scenarios was tested using a finite-element model of the human head and neck. It was compared with cadaver crash sled experiment with good correlation. Then, simulations were performed with a sinusoidal velocity (5-22 G) applied at T1 60° to the horizontal plane. The model with relaxed muscle activation had delayed and decreased peak head rotation compared with passive properties only. Full muscle activation decreased the injury risk for the 13.5-22 G impacts. A sensitivity study of the impact angle showed a very slight variation of the resulting neck flexion, and 1° change affected all ligament injury predictions less than 4%. Finally, simulations with helmets resulted in increased ligament and disc strains with increasing helmet mass and with an anterior or inferior shift of the centre of gravity. It is concluded that the hypothesis seems to hold.
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| 3. |
- Davidsson, Johan, 1967, et al.
(författare)
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Experiments and Mathematical Modeling for Evaluation of Non-Lethal Weapons
- 2015
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Ingår i: 8th European Symposium on Non-lethal Weapons, May 18-20, Ettlingen, Germany. ; , s. V21-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The biomechanical response of new and existing non-lethal weapons (NLWs) are to be determined to assess their effectiveness and safety, i.e. the type of injury produced and the risk of such injuries, for the target population and bystanders. The effect and risk of injury varies widely for most NLWs (from no effect to lethality) depending on how the weapon is used, the body region hit and variability in biomechanical response between humans. Commonly the effectiveness and safety provided by a particular NLW are assessed using real-life data from situations in which the NLW have been employed. However, for new NLWs it is necessary to conduct experimental studies using modelsof the human such as anthropometric tests devises (ATDs) and Human Body Models (HBM), post mortem human subjects (PMHSs), animals and cell cultures.While the assessment of possible NLW related injuries in ATDs and PMHSs are crude, animals and cell cultures are excellent for studies of injury mechanisms and injury criteria. For some injuries these mechanisms and criteria can be scaled to humans. The obtained data can also be used in the development of injury risk functions for humans but commonly require scaling. Several of the scaling techniques used in the past are crude. Computer simulation with finite element technique can be used to improve the understanding of experimental studies and to construct injury risk functions at tissue level using data from animal or cell culture experiments. The tissue risk functions can then be used in finite element models of humans to support the development of global injury criteria; to enable theevaluation of new NLWs using ATDs. In this paper we will describe animal models used to study mild and moderate brain injuries and associated finite element models. The paper aims at illustrating the benefit of combining models in biomechanics research and proving guidelines for such studies.
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| 6. |
- Halldin, Peter, et al.
(författare)
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Finite element analysis of the effects of head-supported mass on neck responses : Complete phase three report, united states army european research office of the U.S.army
- 2006
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Rapport (refereegranskat)abstract
- The objectives for the whole project were to: I. determine the relationships between head supported mass and the risk of neck injuries. The results should be used in a Graphical user interface. In this phase three report has also the Graphical User Interface (GUI) been evaluated and the question about the how the muscle activation affect the injury risk. II. to develop and implement a 3D numerical muscle model. Results: I. The KTH neck model has successfully been used to generate results for the GUI. Results from all simulations have been reported and sent to Titan Corporation that is contracted by USAARL to program the GUI. The GUI that uses an interpolation method to calculate the neck injury risk for a general helmet with a user defined HSM configuration shows to give realistic interpolated values compared to the FE model of the neck. II. The 3D muscle model for the cervical spine includes 22 pairs of muscles. The solid muscle model showed to stabilize the vertebral column better than the spring muscle model. The model is still under evaluation and need further validation to be used in the HSM evaluation project.
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| 7. |
- Hedenstierna, Louise, et al.
(författare)
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Neither low social support nor low decision latitude at work is associated with disease remission among patients with rheumatoid arthritis : results from the Swedish EIRA study
- 2022
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Ingår i: Arthritis Research & Therapy. - : BioMed Central. - 1478-6354 .- 1478-6362. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate the association between psychosocial vulnerability, defined as either low social support or low decision latitude at work, and disease remission at 3, 12, and 60 months in patients with rheumatoid arthritis (RA).METHODS: This cohort study included all patients enrolled in both the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) 1996-2015 and the Swedish Rheumatology Quality Register (SRQ, n = 2820). Information on social support and decision latitude at work at RA diagnosis were identified from the EIRA questionnaire. Indexes for levels of social support and decision latitude at work, respectively, were calculated based on the questionnaire. Low social support and low decision latitude at work, respectively, were identified by a score in the lowest quartile and compared with the three other quartiles (not low). Disease-activity parameters were retrieved from SRQ at 3, 12, and 60 months. The associations between social support or decision latitude at work, respectively, and Disease Activity Score 28 joint count with C-reactive protein (DAS28-CRP) remission were analysed using logistic regression models adjusted for age, sex, smoking habits, alcohol habits, symptom duration, and educational level.RESULTS: Having low social support (n = 591) was not associated with DAS28-CRP remission at 3 (OR 0.93, 95% CI 0.74-1.16), 12 (OR 0.96, 95%CI 0.75-1.23), or 60 (OR 0.89, 95%CI 0.72-1.10) months compared to not low social support (n = 2209). No association was observed for low (n = 212) versus not low (n = 635) decision latitude at work and DAS28-CRP remission at 3 (OR 0.84, 95%CI 0.54-1.31), 12 (OR 0.81, 95%CI 0.56-1.16), or 60 (OR 1.37, 95%CI 0.94-2.01) months.CONCLUSION: In a country with general access to healthcare, psychosocial vulnerability does not influence the likelihood of achieving remission in early RA.
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| 8. |
- Hedenstierna, Sofia, 1976-
(författare)
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3D Finite Element Modeling of Cervical Musculature and its Effect on Neck Injury Prevention
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Injuries to the head and neck are potentially the most severe injuries in humans, since they may damage the nervous system. In accidents, the cervical musculature stabilizes the neck in order to prevent injury to the spinal column and is also a potential site for acute muscle strain, resulting in neck pain. The musculature is consequently an important factor in the understanding of neck injuries. There is however a lack of data on muscle response and little is known about the dynamics of the individual muscles. In this thesis the numerical method of Finite Elements (FE) is used to examine the importance of musculature in accidental injuries. In order to study the influence of a continuum musculature, a 3D solid element muscle model with continuum mechanical material properties was developed. It was hypothesized that a 3D musculature model would improve the biofidelity of a numerical neck model by accounting for the passive compressive stiffness, mass inertia, and contact interfaces between muscles. A solid element representation would also enable the study of muscle tissue strain injuries. A solid element muscle model representing a 50th percentile male was created, based on the geometry from MRI, and incorporated into an existing FE model of the spine. The passive material response was modeled with nonlinear-elastic and viscoelastic properties derived from experimental tensile tests. The active forces were modeled with discrete Hill elements. In the first version of the model the passive solid element muscles were used together with separate active spring elements. In the second version the active elements were integrated in the solid mesh with coincident nodes. This combined element, called the Super-positioned Muscle Finite Element (SMFE), was evaluated for a single muscle model before it was incorporated in the more complex neck muscle model. The main limitation of the SMFE was that the serial connected Hill-type elements are unstable due to their individual force-length relationship. The instabilities in the SMFE were minimized by the addition of passive compressive stiffness from the solid element and by the decreased gradient of the force-length relation curve. The solid element musculature stabilized the vertebral column and reduced the predicted ligament strains during simulated impacts. The solid element compressive stiffness added to the passive stiffness of the cervical model. This decreased the need for additional active forces to reproduce the kinematic response of volunteers during impact. The active response of the SMFE improved model biofidelity and reduced buckling of muscles in compression. The solid element model predicted forces, strains, and energies for individual muscles and showed that the muscle response is dependent on impact direction and severity. For each impact direction, the model identified a few muscles as main load carriers that corresponded to muscles generating high EMG signals in volunteers. The single largest contributing factor to neck injury prediction was the muscle active forces. Muscle activation reduced the risk of injury in ligaments in high-energy impacts. The most urgent improvements of the solid element muscle model concerns: the stability of the SMFE; the boundary conditions from surrounding tissues; and more detailed representations of the myotendinous junctions. The model should also be more extensively validated for the kinematical response and for the muscle load predictions. It was concluded that a solid muscle model with continuum mechanical material properties improves the kinematical response and injury prediction of a FE neck model compared to a spring muscle model. The solid muscle model can predict muscle loads and provide insight to how muscle dynamics affect spinal stability as well as muscle acute strain injuries.
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