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- Callaghan, Terry, et al.
(författare)
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Multi-Decadal Changes in Tundra Environments and Ecosystems : Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF)
- 2011
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40:6, s. 705-716
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the responses of tundra systemsto global change has global implications. Most tundraregions lack sustained environmental monitoring and oneof the only ways to document multi-decadal change is toresample historic research sites. The International PolarYear (IPY) provided a unique opportunity for such researchthrough the Back to the Future (BTF) project (IPY project#512). This article synthesizes the results from 13 paperswithin this Ambio Special Issue. Abiotic changes includeglacial recession in the Altai Mountains, Russia; increasedsnow depth and hardness, permafrost warming, andincreased growing season length in sub-arctic Sweden;drying of ponds in Greenland; increased nutrient availabilityin Alaskan tundra ponds, and warming at mostlocations studied. Biotic changes ranged from relativelyminor plant community change at two sites in Greenland tomoderate change in the Yukon, and to dramatic increasesin shrub and tree density on Herschel Island, and in subarcticSweden. The population of geese tripled at one sitein northeast Greenland where biomass in non-grazed plotsdoubled. A model parameterized using results from a BTFstudy forecasts substantial declines in all snowbeds andincreases in shrub tundra on Niwot Ridge, Colorado overthe next century. In general, results support and provideimproved capacities for validating experimental manipulation,remote sensing, and modeling studies.
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| 2. |
- Johansson, Maria E, 1977, et al.
(författare)
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alpha 7 Nicotinic Acetylcholine Receptor Is Expressed in Human Atherosclerosis and Inhibits Disease in Mice-Brief Report
- 2014
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Ingår i: Arteriosclerosis Thrombosis and Vascular Biology. - : Ovid Technologies (Wolters Kluwer Health). - 1079-5642 .- 1524-4636. ; 34:12, s. 2632-2636
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Tidskriftsartikel (refereegranskat)abstract
- Objective-Cholinergic pathways of the autonomic nervous system are known to modulate inflammation. Because atherosclerosis is a chronic inflammatory condition, we tested whether cholinergic signaling operates in this disease. We have analyzed the expression of the alpha 7 nicotinic acetylcholine receptor (alpha 7nAChR) in human atherosclerotic plaques and studied its effects on the development of atherosclerosis in the hypercholesterolemic Ldlr(-/-) mouse model. Approach and Results-alpha 7nAChR protein was detected on T cells and macrophages in surgical specimens of human atherosclerotic plaques. To study the role of alpha 7nAChR signaling in atherosclerosis, male Ldlr(-/-) mice were lethally irradiated and reconstituted with bone marrow from wild-type or alpha 7nAChR-deficient animals. Ablation of hematopoietic cell alpha 7nAChR increased aortic atherosclerosis by 72%. This was accompanied by increased aortic interferon-gamma mRNA, implying increased Th1 activity in the absence of a7nAChR signaling. Conclusions-The present study shows that signaling through hematopoietic alpha 7nAChR inhibits atherosclerosis and suggests that it operates by modulating immune inflammation. Given the observation that alpha 7nAChR is expressed by T cells and macrophages in human plaques, our findings support the notion that cholinergic regulation may act to inhibit disease development also in man.
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| 4. |
- Widhe, Mona, et al.
(författare)
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Recombinant spider silk with cell binding motifs for specific adherence of cells
- 2013
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 34:33, s. 8223-8234
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Tidskriftsartikel (refereegranskat)abstract
- Silk matrices have previously been shown to possess general properties governing cell viability. However, many cell types also require specific adhesion sites for successful in vitro culture. Herein, we have shown that cell binding motifs can be genetically fused to a partial spider silk protein, 4RepCT, without affecting its ability to self-assemble into stable matrices directly in a physiological-like buffer. The incorporated motifs were exposed in the formed matrices, and available for binding of integrins. Four different human primary cell types; fibroblasts, keratinocytes, endothelial cells and Schwann cells, were applied to the matrices and investigated under serum-free culture conditions. Silk matrices with cell binding motifs, especially RGD, were shown to promote early adherence of cells, which formed stress fibers and distinct focal adhesion points. Schwann cells acquired most spread-out morphology on silk matrices with IKVAV, where significantly more viable cells were found, also when compared to wells coated with laminin. This strategy is thus suitable for development of matrices that allow screening of various cell binding motifs and their effect on different cell types.
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