| 1. |
- García-Valdés, Raúl, et al.
(författare)
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Climate change impacts on long-term forest productivity might be driven by species turnover rather than by changes in tree growth
- 2020
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 29:8, s. 1360-1372
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Climate change impacts forest functioning and services through two inter-related effects. First, it impacts tree growth, with effects, for example, on biomass production. Second, climate change also reshuffles community composition, with further effects on forest functioning. However, the relative importance of these two effects has rarely been studied. Here, we developed a new modelling approach to investigate these relative importances for forest productivity. Location: Eleven forest sites in central Europe. Time period: Historical (1990) and end-of-21st-century climate-like conditions. We simulated 2,000 years of forest dynamics for each set of conditions. Major taxa studied: Twenty-five common tree species in European temperate forests. Methods: We coupled species distribution models and a forest succession model, working at complementary spatial and temporal scales, to simulate the climatic filtering that shapes potential tree species pools, the biotic filtering that shapes realized communities and the functioning of these realized communities in the long-term. Results: Under an average temperature increase (relative to 1901–1990) of between 1.5 and 1.7 °C, changes in simulated forest productivity were caused mostly by changes in the growth of persisting tree species. With an average temperature increase of 3.6–4.0 °C, changes in simulated productivity at sites that currently have a mild climate were again caused predominantly by changes in tree species growth. However, at the warmest and coldest sites, changes in productivity were related mostly to shifts in species composition. In general, at the coldest sites, forest productivity is likely to be enhanced by climate change, whereas at the warmest sites the productivity might increase or decrease depending on the future precipitation regime. Main conclusions: A combination of two complementary modelling approaches that address questions at the interface between biogeography, community ecology and ecosystem functioning, reveals that climate change-driven community reshuffling in the long term might be crucially important for ecosystem functioning.
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| 2. |
- Giraldo Mejia, Hugo F., et al.
(författare)
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Antibacterial performance of hybrid nanocomposite coatings containing clay and silver nanoparticles
- 2021
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Ingår i: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 628
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Tidskriftsartikel (refereegranskat)abstract
- The performance of biocide-based coatings for health care applications, using the drug delivery method, depends primarily on the diffusive properties of storage material. When the active component is ionic silver, supplied from silver nanoparticles, an additional dissolution step must occur in the bulk of the storage material. This article presents the silver release behavior of organic-inorganic sol-gel hybrid coatings and the effect of claynanoparticle composite, added in the sol-type formulation. Hybrid coatings were synthesized from the hydrolytic condensation of (3-glycidoxypropyl)-trimethoxysilane (GPTMS) and tetraethoxysilane in acidic media. Clay nanoparticles, previously silanized with GPTMS, and silver nitrate were used as additives in sol-gel formulations, alternatively. Coatings were deposited on microscope glass slides by the dip-coating process at a constant withdrawal rate and densified at 150 degrees C. Through small angle X-ray scattering from a synchrotronic source, and transmission electron microscopy, the structure of hybrid matrix, silver nanoparticles morphology and the storability behavior of silver nanoparticles under leaching conditions was analyzed. Silver releasing process was analyzed by following the evolution of silver nanoparticles remaining in the coatings, by UV-visible spectroscopy, and the increase of silver ions in the liquid medium, using inductively coupled plasma with optical emission spectroscopy. Microbiological studies showed that the lixiviated silver exhibited inhibitory properties against E. coli in LB broth. The clay nanoparticles worked as a stabilizing agent avoiding the agglomeration of silver both on the sols and on the surface of the thermally densified coatings.
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| 3. |
- Valdes, Raúl, et al.
(författare)
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Cellular Trafficking of Glutathione Transferase M2-2 Between U373MG and SHSY-S7 Cells is Mediated by Exosomes
- 2021
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Ingår i: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1029-8428 .- 1476-3524. ; 39:2, s. 182-190
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Tidskriftsartikel (refereegranskat)abstract
- The enzyme glutathione transferase M2-2, expressed in human astrocytes, increases its expression in the presence of aminochrome and catalyzes the conjugation of aminochrome, preventing its toxic effects. Secretion of the enzyme glutathione transferase M2-2 from U373MG cells, used as a cellular model for astrocytes, has been reported, and the enzyme is taken up by neuroblastoma SYSH-S7 cells and provide protection against aminochrome. The present study provides evidence that glutathione transferase M2-2 is released in exosomes from U373MG cells, thereby providing a means for intercellular transport of the enzyme. With particular relevance to Parkinson disease and other degenerative conditions, we propose a new mechanism by which astrocytes may protect dopaminergic neurons against the endogenous neurotoxin aminochrome.
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