| 1. |
- Forsman, Huamei, et al.
(författare)
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The beta-galactoside binding immunomodulatory lectin galectin-3 reverses the desensitized state induced in neutrophils by the chemotactic peptide f-Met-Leu-Phe: role of reactive oxygen species generated by the NADPH-oxidase and inactivation of the agonist
- 2008
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 1460-2423 .- 0959-6658. ; 18:11, s. 905-12
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils interacting with a chemoattractant gradually become nonresponsive to further stimulation by the same agonist, a process known as desensitization. Receptor desensitization is a highly regulated process that involves different mechanisms depending on which receptor-ligand pair that is studied. Galectin-3, a member of a large family of beta-galactoside-binding lectins, has been suggested to be a regulator of the inflammatory process, augmenting or directly triggering the neutrophil functional repertoire. We show here that the desensitized state of neutrophils interacting with the chemotactic peptide fMLF is broken by galectin-3 and that this is achieved through an oxygen radical-mediated inactivation of the chemoattractant. The effect was inhibited by the competitor lactose and required the affinity of galectin-3 for N-acetyllactosamine, a saccharide typically found on cell surface glycoproteins. The latter was shown using a galectin-3 mutant that lacked N-acetyllactosamine binding activity, and this protein was not active. The mechanism behind the inactivation of the chemoattractant was found to depend on the ability of galectin-3 to induce a neutrophil generation/secretion of reactive oxygen species which in combined action with myeloperoxidase inactivated the peptides.
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| 2. |
- Karlsson, Anna, 1967, et al.
(författare)
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Galectin-3 functions as an opsonin and enhances the macrophage clearance of apoptotic neutrophils.
- 2009
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 1460-2423 .- 0959-6658. ; 19:1, s. 16-20
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Tidskriftsartikel (refereegranskat)abstract
- Galectin-3, a beta-galactoside binding, endogenous lectin, takes part in various inflammatory events and is produced in substantial amounts at inflammatory foci. We investigated whether extracellular galectin-3 could participate in the phagocytic clearance of apoptotic neutrophils by macrophages, a process of crucial importance for termination of acute inflammation. Using human leukocytes, we show that exogenously added galectin-3 increased the uptake of apoptotic neutrophils by monocyte-derived macrophages (MDM). Both the proportion of MDM that engulfed apoptotic prey and the number of apoptotic neutrophils that each MDM engulfed were enhanced in the presence of galectin-3. The effect was lactose-inhibitable and required galectin-3 affinity for N-acetyllactosamine, a saccharide typically found on cell surface glycoproteins, since a mutant lacking this activity was without effect. The enhanced uptake relied on the presence of galectin-3 during the cellular interaction and was paralleled by lectin binding to apoptotic cells as well as MDM in a lactose-dependent manner. These findings suggest that galectin-3 functions as a bridging molecule between phagocyte and apoptotic prey, acting as an opsonin. The process of clearance, whereby apoptotic neutrophils are removed by macrophages, is crucial for the resolution of acute inflammation and our data imply that the increased levels of galectin-3 often found at inflammatory sites could potently affect this process.
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| 3. |
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| 4. |
- Leffler, Karin, et al.
(författare)
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On the existence of a unique stress-deformation relation for an adhesive layer loaded in shear
- 2005
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Ingår i: 11th International Conference on Fracture (ICF11), Turin, Italy 20-25 March 2005. - : Curran Associates, Inc.. - 9781617820632 ; , s. 3763-3768
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Konferensbidrag (refereegranskat)abstract
- An experimental method to determine the complete stress vs. deformation relation for a thin adhesive layer loaded in shear is presented. The experiments are performed by use of a classical specimen geometry, i.e. the end-notch flexure specimen, though the experiments are evaluated based on a novel inverse technique. With this technique, the instantaneous energy release rate is first evaluated by use of a theory for the specimen based on the Euler-Bernoulli beam theory. Effects of a flexible adhesive layer are considered in an approximate way. From the energy release rate, the stress-deformation relation is evaluated using an inverse method. In order for the theory to be valid, the adherends of the specimen are only allowed to deform elastically. Quasi-static experiments are performed using a servo-hydraulic testing machine. In the experiments, the displacement of the loading point is gradually increased to obtain a constant velocity of the shear deformation at the crack tip. Formation of micro-cracks and the propagation of a macro-crack are monitored during the experiments by use of a CCD-camera attached to a microscope. By varying the heights of the adherends, the size of the process zone in front of the crack tip changes from about 200 to 400 times the thickness of the adhesive layer. The results of the experiments give a fracture toughness of 2.5 kJ/m 2 , a critical shear deformation of 0.13 mm, and a maximal strength of 30 MPa independent of the specimen geometry. The experiments show consistent results. The results show that if the process zone is large as compared to the thickness of the adhesive layer, the shear stress – shear deformation relation can be considered as a constitutive property of the adhesive layer.
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| 5. |
- Leffler, Karin
(författare)
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Shear Behaviour of Adhesive Layers
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- An experimental method to determine the complete stress versus deformation relation for a thin adhesive layer loaded in shear is presented. The work is based on a classical specimen geometry, i.e. the end-notch flexure specimen (ENF-specimen) and the experiments are evaluated based on an inverse method. By studying the energy balance at the crack tip an expression for the energy release rate is derived. The theory considers the effects of a flexible adhesive layer and is based on beam theory. From the energy release rate the stress-deformation relation is derived using the inverse method.Quasi-static experiments are performed using a servo-hydraulic testing machine. The deformation process at the crack tip is monitored during the experiments by use of a CCD-camera attached to a microscope. The method requires differentiation of the energy-deformation relation, therefore a Monte-Carlo simulation is performed to investigate how small errors in the data acquisition system affects the final stress-deformation relation. Small errors in the measurement of the force and shear deformation give small effects on the final stress-deformation relation.Experiments on three different geometries of the specimen are performed. The experiments give consistent results. It is shown that if the process zone in front of the crack tip is large, then the stress-deformation relation does not depend on the dimensions of the adherends. Thus, the constitutive relation can be considered to be a property of the adhesive layer.
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| 6. |
- Leffler, Karin, et al.
(författare)
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Shear behaviour of adhesive layers
- 2007
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Ingår i: International Journal of Solids and Structures. - : Elsevier. - 0020-7683 .- 1879-2146. ; 44:2, s. 530-545
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Tidskriftsartikel (refereegranskat)abstract
- An experimental method to determine the complete stress versus deformation relation for a thin adhesive layer loaded in shear is presented. The method is based on a classic specimen geometry; the end-notch flexure specimen. The experiments are evaluated using an inverse method. First, the variation of the energy release rate with respect to the shear deformation at the crack tip is measured during an experiment. Then the traction–deformation relation is derived using an inverse method. The theory is based on the path-independence of the J-integral and considers the effects of a flexible adhesive layer.Quasi-static experiments on three different specimen geometries are performed using a servo-hydraulic testing machine. The experiments give consistent results. This shows that the traction–deformation relation can be taken as independent of the dimensions of the adherends. Thus, the constitutive relation can be considered as a property of the adhesive layer. The deformation process at the crack tip is also monitored during the experiments by the use of a digital camera attached to a microscope.
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| 7. |
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| 8. |
- Leffler, Per, et al.
(författare)
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Metodik för rapportering av ingående ämnen i ammunition som har betydelse för FM-verksamhet.
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Projektet Ammunitionsmiljö har undersökt modeller för miljörapportering av ammunition kopplat till miljökonsekvensanalys, samt generering av miljödata till en accessdatafil länkad med ammunitionskatalogen AMKAT. I föreliggande rapport presenteras genomfört arbete med utökade mallar för miljörapportering. Dessa bygger på tidigare föreslagen access-datafil, den första delleveransen till Försvarets Materielverk (FMV) 2011-10-31. Projektet levereras i 3 olika delleveranser och denna rapport utgör den tredje delleveransen
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| 9. |
- Maurice, Christian, et al.
(författare)
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Improving soil investigations at brownfield sites using a flexible work strategy and screening methods inspired by the US Environmental Protection Agency's Triad approach
- 2007
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Ingår i: Ambio. - 0044-7447 .- 1654-7209. ; 36:6, s. 502-11
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Tidskriftsartikel (refereegranskat)abstract
- Investigations of polluted brownfield sites and sample analyses are expensive, and the resulting data are often of poor quality. Efforts are needed, therefore, to improve the methods used in investigations of brownfield sites to both reduce costs and improve the quality of the results. One approach that could be useful for both of these purposes is the triad strategy, developed by the US Environmental Protection Agency, in which managing uncertainty is a central feature. In the investigations reported here, a field study was conducted to identify possible ways in which uncertainties could be managed in practice. One example considered involves optimizing the uncertainty by adjusting the sizes of samples and the efforts expended in analytical work according to the specific aims of the project. In addition, the potential utility of several toxicity assessment methods for screening sites was evaluated. As well as presenting the results of these assessments, in this contribution we discuss ways in which a flexible work strategy and screening methods inspired of the triad philosophy could be incorporated into the Swedish approach to remediate brownfield sites. A tiered approach taking advantage of field and screening methods is proposed to assess brownfield sites focusing on the response and acceptable uncertainty that are required for the task.
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