Assessment of river contamination by estrogenic compounds in Paris area (France)

Wastewater treatment plants (WWTPs) receive a large spectrum of endocrine disrupting compounds (EDCs) that are partially eliminated during treatment processes and discharged into rivers. Given the lack of information in France about river contamination by EDCs, we chose to examine estrogenic potential of WWTP influents, effluents and receiving waters in Paris and its suburbs. Water samples were analyzed using gas chromatography coupled with mass spectrometry for quantifying natural and synthetic estrogens combined with an in vitro estrogenicity bioassay associated to a high pressure liquid chromatography fractionation. The four estrogens investigated, Estrone (E1), 17beta-Estradiol (E2), Estriol (E3) and 17alpha-Ethinylestradiol (EE2) were found in all WWTP and river samples at concentrations ranging from 2.7 to 17.6 ng/l and 1.0 to 3.2 ng/l, respectively. The synthetic estrogen EE2 seems more resistant to biodegradation in WWTPs and thus accounted for 35-50% of the estimated estrogenic activity in rivers. However, fractionation of samples and differences between concentrations of E1, E2, E3 and EE2 and the estrogenic activity measured by the in vitro bioassay suggested a complexity of mechanisms underlying the biological response that could not be attributed only to the investigated molecules.     

Yield Strength Enhancement Without Ductility Loss Through Controlling the Intercritical Annealing Time in Medium-Mn Steels

Herein, the effect of shortening the intercritical annealing (IA) time in a two-step process “intercritical annealing and tempering (IAT)” on the microstructure and the mechanical properties of medium-manganese steel (MMnS) made of Fe–0.05C–7Mn–1.5Cu–1.5Ni–1.5Al–1.5Si–0.5Mo (wt%) and containing copper-rich (CRP) and Ni(Al/Mn) precipitates is investigated. The atom probe tomography (APT), electron backscattering diffraction (EBSD), and the synchrotron X-ray diffraction (SYXRD) are used to study precipitation, phase microstructure evolution, the austenite stability, and deformation mechanisms. Shortening the IA step, which is carried out at 700 °C, from 2 min (IAT-2) to 1 min (IAT-1), results in a yield strength (YS) increment of around 218 MPa with less than 1% loss of ductility. While the enhanced yield strength in IAT-1 is attributed to the four times higher precipitates’ number density (n), the insignificant loss of ductility is attributed to the enhanced austenite stability factor from 4.5 to 9.2 in IAT-2 and IAT-1, respectively. The simultaneous increase in YS without ductility loss reflects that controlling the IA time is a promising strategy to overcome the yield strength and ductility trade-off without the need for higher additions of costly alloying elements such as Ni, Al, Mn, and Cu.     

Synthesis and Characterization of α- Fe2O3 NPs/P-Si Heterojunction for High Sensitive Photodetector

Silicon - In this work, Fe2O3 nanoparticles (NPs) were synthesized successfully through simple chemical precipitation method. The absorption spectra of the synthesized Fe2O3 NPs was studied by...     

Double-Bond Isomerization of Rapeseed Oil Methyl Esters in a Continuous Flow Reactor Efficiently Catalyzed by H-Mordenite

Unsaturated fatty acids are attractive alternatives to fossil-based materials as a source of hydrocarbons, but potential applications are limited by the preset chain length of 16–20 carbon atoms. However, if the double bond can be randomly moved along the chain, subsequent bond-breaking operations such as ethenolysis or oxidative cleavage will give rise to products with chain lengths ranging from 2 to 18 carbon atoms. A process for the double bond isomerization of rapeseed oil methyl esters in a flow-through reactor using zeolites as the catalyst is herein disclosed. Using H-mordenite as the catalyst at a flow of 0.125 mL min⁻¹ at 290 °C, near equilibrium isomerization is reached with up to 49% recovery of linear monomeric products after 5 h and up to 44% after 48 h. The main side products are oligomers (3%–15%) and skeletal isomerization products (10%–23%). Practical applications: With a suitable follow-up modification addressing the double bond (metathesis, ozonolysis, oxidative cleavage), the product mixtures of double-bond positional isomers can be used in the production of short-chain base chemicals. In repetitive combination with metathesis catalysis, biofuels with customized chain length distributions can be generated.