Found 9764 publications. Showing page 189 of 391:
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Land surface temperature validation for WACMOS-ET. Reference input data set validation report. NILU report
The Land Surface Temperature (LST) products generated specifically for theWAter Cycle Observation Multi-mission Strategy - EvapoTranspiration (WACMOS-ET)project, funded by the European Space Agency (ESA), are evaluated with respect to their overall quality. LST products derived from observations acquired by the Advanced Along-Track Scanning Radiometer (AATSR), the Multi-Functional Transport Satellite (MTSAT), and the Geostationary Operational Environmental Satellite (GOES) were studied here. Following previously established best-practices on LST validation, the evaluation includes both a qualitative component addressing general issues with the data, as well as a quantitative component, which compares the LST products directly against a reference dataset. For the latter satellite LST is compared against both ground-based in situ datasets acting as a source of absolute reference data and against independent satellite-based LST products from other sensors to provide a spatially exhaustive relative comparison.
2017
Land surface temperature determination from ATSR-family of instruments and the Sentinel-3 SLSTR. NILU PP
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Lack of mutagenicity of TiO2 nanoparticles in vitro despite cellular and nuclear uptake
The potential genotoxicity of titanium dioxide (TiO2) nanoparticles (NPs) is a conflictive topic because both positive and negative findings have been reported. To add clarity, we have carried out a study with two cell lines (V79–4 and A549) to evaluate the effects of TiO2 NPs (NM-101), with a diameter ranging from 15 to 60 nm, at concentrations 1–75 μg/cm2. Using two different dispersion procedures, cell uptake was determined by Transmission Electron Microscopy (TEM). Mutagenicity was evaluated using the Hprt gene mutation test, while genotoxicity was determined with the comet assay, detecting both DNA breaks and oxidized DNA bases (with formamidopyrimidine glycosylase - Fpg). Cell internalization, as determined by TEM, shows TiO2 NM-101 in cytoplasmic vesicles, as well as close to and inside the nucleus. Such internalization did not depend on the state of agglomeration, nor the dispersion used. In spite of such internalization, no cytotoxicity was detected in V79–4 cells (relative growth activity and plating efficiency assays) or in A549 cells (AlamarBlue assay) after exposure lasting for 24 h. However, a significant decrease in the relative growth activity was detected at longer exposure times (48 and 72 h) and at the highest concentration 75 µg/cm2. When the modified enzyme-linked alkaline comet assay was performed on A549 cells, although no significant induction of DNA damage was detected, a positive concentration-effects relationship was observed (Spearman’s correlation = 0.9, p 0.0001). Furthermore, no significant increase of DNA oxidized purine bases was observed. When the frequency of Hprt gene mutants was determined in V79–4 cells, no increase was observed in the exposed cells, relative to the unexposed cultures. Our general conclusion is that, under our experimental conditions, TiO2 NM-101 exposure does not exert mutagenic effects despite the evidence of NP uptake by V79–4 cells.
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