Found 9886 publications. Showing page 226 of 396:
2012
Non-target screening (NTS) including suspect screening with high resolution mass spectrometry has already shown its feasibility in detecting and identifying emerging contaminants, which subsequently triggered exposure mitigating measures. NTS has a large potential for tasks such as effective evaluation of regulations for safe marketing of substances and products, prioritization of substances for monitoring programmes and assessment of environmental quality. To achieve this, a further development of NTS methodology is required, including: (i) harmonized protocols and quality requirements, (ii) infrastructures for efficient data management, data evaluation and data sharing and (iii) sufficient resources and appropriately trained personnel in the research and regulatory communities in Europe. Recommendations for achieving these three requirements are outlined in the following discussion paper. In particular, in order to facilitate compound identification it is recommended that the relevant information for interpretation of mass spectra, as well as about the compounds usage and production tonnages, should be made accessible to the scientific community (via open-access databases). For many purposes, NTS should be implemented in combination with effect-based methods to focus on toxic chemicals.
Springer
2019
2025
2013
2012
2012
2015
High Arctic UV radiation levels in the spring of 2011 caused by unprecedented chemical ozone loss. NILU PP
2012
2012
The potential re-design of the current deposition monitoring network in Poland was assessed by hierarchical clustering analysis. This statistical method determines the inherent or natural groupings of datasets, and/or to provide a summarization of data into groups using different metrics to assess the (di)similarity. The metrics are based on the correlation, to assess the temporal similarity, the Euclidean distance, to assess the magnitude similarity, and the combination of both. This method was used to assess the areas with similar deposition patters across the country based on measurement and model data for acidic compounds and heavy metals. The analysis clearly identified stations potentially redundant or measuring unique deposition patters and regions that represent the potential location of a single station.
NILU
2023
2004
2014
2007
2007
2008
2000
Hepato(Geno)Toxicity Assessment of Nanoparticles in a HepG2 Liver Spheroid Model
(1) In compliance with the 3Rs policy to reduce, refine and replace animal experiments, the development of advanced in vitro models is needed for nanotoxicity assessment. Cells cultivated in 3D resemble organ structures better than 2D cultures. This study aims to compare cytotoxic and genotoxic responses induced by titanium dioxide (TiO2), silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs) in 2D monolayer and 3D spheroid cultures of HepG2 human liver cells. (2) NPs were characterized by electron microscopy, dynamic light scattering, laser Doppler anemometry, UV-vis spectroscopy and mass spectrometry. Cytotoxicity was investigated by the alamarBlue assay and confocal microscopy in HepG2 monolayer and spheroid cultures after 24 h of NP exposure. DNA damage (strand breaks and oxidized base lesions) was measured by the comet assay. (3) Ag-NPs were aggregated at 24 h, and a substantial part of the ZnO-NPs was dissolved in culture medium. Ag-NPs induced stronger cytotoxicity in 2D cultures (EC50 3.8 µg/cm2) than in 3D cultures (EC50 > 30 µg/cm2), and ZnO-NPs induced cytotoxicity to a similar extent in both models (EC50 10.1–16.2 µg/cm2). Ag- and ZnO-NPs showed a concentration-dependent genotoxic effect, but the effect was not statistically significant. TiO2-NPs showed no toxicity (EC50 > 75 µg/cm2). (4) This study shows that the HepG2 spheroid model is a promising advanced in vitro model for toxicity assessment of NPs.
MDPI
2020
2021