Screening Estrogenic Activities of Chemicals or Mixtures In Vivo Using Transgenic (cyp19a1b-GFP) Zebrafish Embryos

The tg(cyp19a1b-GFP) transgenic zebrafish expresses GFP (green fluorescent protein) under the control of the cyp19a1b gene, encoding brain aromatase. This gene has two major characteristics: (i) it is only expressed in radial glial progenitors in the brain of fish and (ii) it is exquisitely sensitive to estrogens. Based on these properties, we demonstrate that natural or synthetic hormones (alone or in binary mixture), including androgens or progestagens, and industrial chemicals induce a concentration-dependent GFP expression in radial glial progenitors. As GFP expression can be quantified by in vivo imaging, this model presents a very powerful tool to screen and characterize compounds potentially acting as estrogen mimics either directly or after metabolization by the zebrafish embryo. This study also shows that radial glial cells that act as stem cells are direct targets for a large panel of endocrine disruptors, calling for more attention regarding the impact of environmental estrogens and/or certain pharmaceuticals on brain development. Altogether these data identify this in vivo bioassay as an interesting alternative to detect estrogen mimics in hazard and risk assessment perspective

Investigation of phase transformation for ferrite-austenite structure in stainless steel thin films

In this work we report on phase transformation of 304 stainless steel thin films due to heat treatment. Ex-situ annealing was applied for evaporated 304 stainless steel thin films inside an ultra-high vacuum chamber with a pressure of 3 × 10− 7 Pa at temperatures of 500 °C and 600 °C. The structure of thin films was studied by X-ray diffraction (XRD) and conversion electron Mössbauer spectroscopy (CEMS) techniques. The results revealed a transformation from α-phase that exhibits a body-centered cubic structure (BCC) to γ-phase that exhibits a face-centered cubic (FCC) due to annealing. In addition, the percentage of γ-phase structure increased with the increase of annealing temperature. Annealing thin films increased the crystal size of both phases (α and γ), however, the increase was nonlinear. The results also showed that phase transformation was produced by recrystallization of α and γ crystals with a temporal evolution at each annealing temperature. The texture degree of thin films was investigated by XRD rocking curve method, while residual stress was evaluated using curvature method.Scopu

On-line fault detection of a fuel rod temperature measurement sensor in a nuclear reactor core using ANNs

In this paper a detailed method for fault detection of an in-core three wires Resistance Temperature Detectors (RTD) sensor is introduced. The method is mainly based on the dependence of the fuel rod temperature profile on control rods elevation and coolant flow rate in a given nuclear reactor. For the implementation, an artificial neural network (ANN) technique has been developed to model the dynamic behaviour of the considered temperature sensor. In order to have more refined model estimation, ANN has been combined with additional noise reduction algorithms. The effective denoising work was done via the discrete wavelet transform (DWT) to remove various kinds of artefacts such as inherent measurement noise. The principle of the adopted fault detection task is based on the calculation of the difference between the ANN model estimated temperature and the online being measured temperature and then compare the deviation with a certain detection threshold to decide the sensor fault. The efficiency of the method is evaluated first on a simulated case and then on the on-line measurements obtained from a real plant. Results confirm the capacity of the developed ANN-based model to estimate a fuel rod temperature with a reasonable accuracy

Growth and characterization of thin ZnO films deposited on glass substrates by electrodeposition technique

Electrodeposition technique was used in order to produce nanometric zinc oxide films on glass insulating substrates. The effect of electrolyte concentration and applied current density on the formation and growth of electrodeposited Zn thin films in aqueous solutions of ZnSO4 were studied. After a thermal oxidation, a characterization of the structural morphology of the films deposited was carried out by optical microscopy (OM), atomic force microscopy (AFM), scanning electron microscopy (SEM) and by grazing incidence X-rays diffraction (GIXD). These characterization techniques show that the grains size of the films after oxidation at temperature 450 °C is between 5 and 15 nm, as well as the structure is polycrystalline nature with several orientations. UV/vis spectrophotometry confirms that it is possible to obtain transparent good ZnO films with an average transmittance of approximately 80% within the visible wavelength region, as well as the optical gap of obtained ZnO films is 3.17 eV

Synthesis, FTIR, NMR, UV–vis and electrochemistry analysis of ferrocenyl Schiff bases

DATA AVAILABILITY : Data will be made available on request.Please read abstract in the article.The Department of Chemical Sciences, the University of Johannesburg.http://www.elsevier.com/locate/ica2023-12-02hj2023ChemistryNon