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- Cyrys, Josef, et al.
(author)
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Variation of NO2 and NOx concentrations between and within 36 European study areas : Results from the ESCAPE study
- 2012
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 62, s. 374-390
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Journal article (peer-reviewed)abstract
- The ESCAPE study (European Study of Cohorts for Air Pollution Effects) investigates long-term effects of exposure to air pollution on human health in Europe. This paper documents the spatial variation of measured NO2 and NOx concentrations between and within 36 ESCAPE study areas across Europe.In all study areas NO2 and NOx were measured using standardized methods between October 2008 and April 2011. On average, 41 sites were selected per study area, including regional and urban background as well as street sites. The measurements were conducted in three different seasons, using Ogawa badges. Average concentrations for each site were calculated after adjustment for temporal variation using data obtained from a routine monitor background site.Substantial spatial variability was found in NO2 and NOx concentrations between and within study areas; 40% of the overall NO2 variance was attributable to the variability between study areas and 60% to variability within study areas. The corresponding values for NOx were 30% and 70%. The within-area spatial variability was mostly determined by differences between street and urban background concentrations. The street/urban background concentration ratio for NO2 varied between 1.09 and 3.16 across areas. The highest median concentrations were observed in Southern Europe, the lowest in Northern Europe.In conclusion, we found significant contrasts in annual average NO2 and NOx concentrations between and especially within 36 study areas across Europe. Epidemiological long-term studies should therefore consider different approaches for better characterization of the intra-urban contrasts, either by increasing of the number of monitors or by modelling.
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| 2. |
- Li, Yu, 1975-
(author)
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Cell Behavior and the Role of Profilin
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Profilin is a key regulator of the microfilament system. It binds to actin monomers in a 1:1 complex, forming the profilin:actin complex, which is the major precursor of actin for filament formation in vivo. The distribution of profilin has been studied in a variety of cells. It is present not only in the cytoplasm but also in the nucleus. In the cytoplasm, it is evenly distributed in a dotted pattern, which is concentrated at the edge of advancing lamellipodia and in the perinuclear region. In the nucleus, it is localized to Speckles and Cajal bodies. However, the distribution of the profilin:actin has not been possible to establish due to the lack of specific reagents. In this thesis I present the localization of the profilin:actin complex and demonstrate the importance of profilin during cell migration.The distribution of the profilin:actin complex was studied using affinity purified antibodies generated against a covalently coupled variant of profilin:actin in colocalization experiments with VASP and the Arp2/3 complex. In both cases, close co-distribution with profilin:actin was found. In order to study the role of profilin in vivo in migratory cells, I used the siRNA-technique to deplete profilin from motile mouse melanoma B16 cells. The particular cell line employed expressed actin fused to green fluorescent protein, which enabled imaging of live cells. Upon profilin-deficiency severe effects on cell behavior were observed, e.g. the cells lacked the ability to form characteristic broad lamellipodia at advancing edges, instead small protruding structures were generated and extended with a significantly reduced rate compared to control cells. Observations were also made suggesting that profilin regulates the expression of actin in mammalian cells.A new experimental system for studies of myoblast fusion and subsequent myotube formation in vitro was also established during these studies. This will facilitate systematic studies of molecular processes connected to muscle development.
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