39 research outputs found
Mixtures of Chemical Pollutants at European Legislation Safety Concentrations: How Safe Are They?
The risk posed by complex chemical mixtures in the environment to wildlife and humans is increasingly debated, but has been rarely tested under environmentally relevant scenarios. To address this issue, two mixtures of 14 or 19 substances of concern (pesticides, pharmaceuticals, heavy metals, polyaromatic hydrocarbons, a surfactant, and a plasticizer), each present at its safety limit concentration imposed by the European legislation, were prepared and tested for their toxic effects. The effects of the mixtures were assessed in 35 bioassays, based on 11 organisms representing different trophic levels. A consortium of 16 laboratories was involved in performing the bioassays. The mixtures elicited quantifiable toxic effects on some of the test systems employed, including i) changes in marine microbial composition, ii) microalgae toxicity, iii) immobilization in the crustacean Daphnia magna, iv) fish embryo toxicity, v) impaired frog embryo development, and vi) increased expression on oxidative stress-linked reporter genes. Estrogenic activity close to regulatory safety limit concentrations was uncovered by receptor-binding assays. The results highlight the need of precautionary actions on the assessment of chemical mixtures even in cases where individual toxicants are present at seemingly harmless concentration
Mixtures of chemical pollutants at European legislation safety concentrations: how safe are they?
The risk posed by complex chemical mixtures in the environment to wildlife and humans is increasingly debated, but has been rarely tested under environmentally relevant scenarios. To address this issue, two mixtures of 14 or 19 substances of concern (pesticides, pharmaceuticals, heavy metals, polyaromatic hydrocarbons, a surfactant, and a plasticizer), each present at its safety limit concentration imposed by the European legislation, were prepared and tested for their toxic effects. The effects of the mixtures were assessed in 35 bioassays, based on 11 organisms representing different trophic levels. A consortium of 16 laboratories was involved in performing the bioassays. The mixtures elicited quantifiable toxic effects on some of the test systems employed, including i) changes in marine microbial composition, ii) microalgae toxicity, iii) immobilization in the crustacean Daphnia magna, iv) fish embryo toxicity, v) impaired frog embryo development, and vi) increased expression on oxidative stress-linked reporter genes. Estrogenic activity close to regulatory safety limit concentrations was uncovered by receptor-binding assays. The results highlight the need of precautionary actions on the assessment of chemical mixtures even in cases where individual toxicants are present at seemingly harmless concentrations
Differential arousal regulation by prokineticin 2 signaling in the nocturnal mouse and the diurnal monkey
The temporal organization of activity/rest or sleep/wake rhythms for mammals is regulated by the interaction of light/dark cycle and circadian clocks. The neural and molecular mechanisms that confine the active phase to either day or night period for the diurnal and the nocturnal mammals are unclear. Here we report that prokineticin 2, previously shown as a circadian clock output molecule, is expressed in the intrinsically photosensitive retinal ganglion cells, and the expression of prokineticin 2 in the intrinsically photosensitive retinal ganglion cells is oscillatory in a clock-dependent manner. We further show that the prokineticin 2 signaling is required for the activity and arousal suppression by light in the mouse. Between the nocturnal mouse and the diurnal monkey, a signaling receptor for prokineticin 2 is differentially expressed in the retinorecipient suprachiasmatic nucleus and the superior colliculus, brain projection targets of the intrinsically photosensitive retinal ganglion cells. Blockade with a selective antagonist reveals the respectively inhibitory and stimulatory effect of prokineticin 2 signaling on the arousal levels for the nocturnal mouse and the diurnal monkey. Thus, the mammalian diurnality or nocturnality is likely determined by the differential signaling of prokineticin 2 from the intrinsically photosensitive retinal ganglion cells onto their retinorecipient brain targets
Changes in afferent and efferent phrenic activities with electrically induced diaphragmatic fatigue
Complex formation of 4,9-diazadodecane-1,12-diamine with copper(II) and zinc(II) ions in aqueous solution
Thermodynamics of simple and mixed complexes of copper(II) with adenosine 5'- monophosphate and spermine
Bioinspired Poly(vinylidene fluoride) Membranes with Directional Release of Therapeutic Essential Oils
Here,
the morphology of polypore fungi has inspired the fabrication
of polyÂ(vinylidene fluoride) (PVDF) membranes with dual porosity by
nonsolvent-induced phase separation (NIPS). The fruiting body of such
microorganisms is constituted of two distinct regions, finger- and
sponge-like structures, which have been successfully mimicked by controlling
the coagulation bath temperature during the NIPS process. The use
of water at 10 °C as coagulant resulted in membranes with the
highest finger-like/sponge-like ratio (53% of the total membrane thickness),
while water at 90 °C allowed the formation of macrovoid-free
membranes. The microchannels and the asymmetric porosity were used
to enhance the oil sorption capacity of the PVDF membranes and to
achieve directional release of therapeutic essential oils. These PVDF
membranes with easily tuned asymmetric channel-like porosity and controlled
pore size are ideal candidates for drug delivery applications