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- Almeida, Joao, et al.
(författare)
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Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere
- 2013
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 502:7471, s. 359-
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Tidskriftsartikel (refereegranskat)abstract
- Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei(1). Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes(2). Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases(2). However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere(3). It is thought that amines may enhance nucleation(4-16), but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid-amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid-dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.
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- Friberg, Ingrid Osika, et al.
(författare)
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Patients' perceptions and factors affecting dialysis modality decisions
- 2018
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Ingår i: Peritoneal Dialysis International. - : SAGE Publications. - 0896-8608. ; 38:5, s. 334-342
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Tidskriftsartikel (refereegranskat)abstract
- Background: Home-based dialysis, including peritoneal dialysis (PD) and home hemodialysis (HHD), has been shown to be associated with tower costs and higher health-related quality of life than in-center HD. However, factors influencing the choice of dialysis modality, including gender, are still not well understood. Methods: A questionnaire was sent out to all dialysis patients in the western region of Sweden in order to investigate factors affecting choice of dialysis modality. Logistic regression was used to analyze the data. Results: Patients were more likelyto have home dialysis if they received predialysis information from 3 or more sources and, to a greater extent, perceived the information as comprehensive and of high quality. In addition, patients had a lower likelihood of receiving home dialysis with increasing age and if they lived closer to a dialysis center. Men had in comparison with women a greater likelihood of receiving home dialysis if they lived with a spouse. In-center dialysis patients more often believed that the social interaction and support provided through in-center HD treatment influenced the choice of dialysis modality. Conclusion: This study highlights the need for increased awareness of various factors that influence the choice of dialysis modality and the importance of giving repeated, comprehensive, high-quality information to dialysis and predialysis patients and their relatives. Information and support must be adapted to the needs of individual patients and their relatives if the intention is to improve patients' well-being and the proportion of patients using home dialysis.
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