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1.
Environ Sci Technol ; 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38323876

RESUMEN

Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricultural application season. Overall, 58 pesticides were observed in the European atmosphere. Low spatial variation of 7 pesticides suggests continental-scale atmospheric dispersal. Based on concentrations in free tropospheric air and at Arctic sites, 22 pesticides were identified to be prone to long-range atmospheric transport, which included 15 substances approved for agricultural use in Europe and 7 banned ones. Comparison between concentrations at remote sites and those found at pesticide source areas suggests long atmospheric lifetimes of atrazine, cyprodinil, spiroxamine, tebuconazole, terbuthylazine, and thiacloprid. In general, our findings suggest that atmospheric transport and persistence of pesticides have been underestimated and that their risk assessment needs to be improved.

2.
Appl Opt ; 54(11): 3412-21, 2015 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-25967332

RESUMEN

We present a nanoscale electro-optic imaging method allowing access to the phase response, which is not amenable to classical second-harmonic generation microscopy. This approach is used to infer the vectorial orientation of single domain ferroelectric nanocrystals, based on polarization-resolved Pockels microscopy. The electro-optic phase response of KTP nanoparticles yields the full orientation in the laboratory frame of randomly dispersed single nanoparticles, together with their electric polarization dipole. The complete vector determination of the dipole orientation is a prerequisite to important applications including ferroelectric nanodomain orientation, membrane potential imaging, and rotational dynamics of single biomolecules.

3.
Sci Rep ; 14(1): 11793, 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38782955

RESUMEN

The negatively charged nitrogen-vacancy center (NV) presents remarkable spin-dependent optical properties that make it an interesting tool for magnetic field sensing. In this paper we exploit the polarization properties of the NV center absorption and emission processes to improve the magnetic sensitivity of an ensemble of NV centers. By simply equipping the experimental set-up of a half-wave plate in the excitation path and a polarizer in the detection path we demonstrate an improvement larger than a factor of two on the NV center magnetic sensitivity.

4.
Chemosphere ; 269: 128738, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33121801

RESUMEN

Nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs, OPAHs) are abundant in the atmosphere and contribute significantly to the health risk associated with inhalation of polluted air. Despite the health hazard they pose, NPAHs and OPAHs were rarely included in monitoring. The aim of this study is to provide the first multi-year temporal trends of the concentrations, composition pattern and fate of NPAHs and OPAHs in air from a site representative of background air quality conditions in central Europe. Samples were collected every second week at a rural background site in the Czech Republic during 2015-2017. Concentrations ranged from 1.3 to 160 pg m-3 for Σ17NPAHs, from 32 to 2600 pg m-3 for Σ10OPAHs and from 5.1 to 4300 pg m-3 for Σ2O-heterocycles. The average particulate mass fraction (θ) ranged from 0.01 ± 0.02 (2-nitronaphthalene) to 0.83 ± 0.22 (1-nitropyrene) for individual NPAHs and from <0.01 ± 0.01 (dibenzofuran) to 0.96 ± 0.08 (6H-benzo (c,d)pyren-6-one) for individual OPAHs and O-heterocycles. The multiyear variations showed downward trends for a number of targeted compounds. This suggests that on-going emission reductions of PAHs are effective also for co-emitted NPAHs and OPAHs.


Asunto(s)
Contaminantes Atmosféricos , Hidrocarburos Policíclicos Aromáticos , Contaminantes Atmosféricos/análisis , República Checa , Monitoreo del Ambiente , Europa (Continente) , Humanos , Nitratos , Oxígeno/análisis , Material Particulado/análisis , Hidrocarburos Policíclicos Aromáticos/análisis
6.
Nanoscale ; 5(18): 8466-71, 2013 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-23852161

RESUMEN

We report an efficient colloidal synthesis of KTiOPO4 (KTP) nanocrystals with excellent crystallinity and the direct observation of optical second-harmonic generation (SHG) from discrete KTP nanocrystals in neurons cultured from mammalian brain cortex. Direct internalization and monitoring of these nanoparticles was successfully achieved without limitations from cytotoxicity, bleaching and blinking emission.


Asunto(s)
Nanopartículas/química , Neuronas/química , Fosfatos/química , Titanio/química , Animales , Células Cultivadas , Corteza Cerebral/citología , Coloides/química , Colorantes Fluorescentes/química , Ratones , Microscopía Fluorescente , Neuronas/citología
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