In vitro cytotoxic activity of phytosynthesized silver nanoparticles using Clematis vitalba L. (Ranunculaceae) aqueous decoction

In this study, we report a bottom-up approach for silver nanoparticles (AgNPs) synthesis using aqueous decoction of aerial parts of Clematis vitalba L. The phytosynthesized AgNPs were characterized by X-ray diffraction (XRD), UV-vis spectroscopy, Fourier Transform-Infrared Spectroscopy (FTIR), Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS) and Bright Field Scanning Transmission Electron Microscopy (BFSTEM). The cytogenotoxicity and phytotoxicity assays of AgNPs were assessed by using Allium test, Evans blue and 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining, root and stem growth potential, and biomass evaluation. The results revealed that AgNPs were in the size range of 1-15 nm and spherical shape. The biosynthesized AgNPs augment the mitodepressive effect, disruption of cellular metabolism, impairment of root and stem growth, and biomass reduction induced by C. vitalba aqueous extracts. These results outline the toxicological profile of the C. vitalba extracts, as well as of the phytogenerated AgNPs and provides scientific perspectives on the use of C. vitalba extracts as reducing and stabilizing agent for the phytosynthesis of metallic nanoparticles

Long-Term Corrosion Testing of Zy-4 in a LiOH Solution under High Pressure and Temperature Conditions

The fuel cladding is one of the most important structural components for maintaining the integrity of a fuel channel and for safely exploitation of a nuclear power plant. The corrosion behavior of a fuel cladding material, Zy-4, under high pressure and temperatures conditions, was analyzed in a static isothermal autoclave under simulated primary water conditions—a LiOH solution at 310 °C and 10 MPa for up to 3024 h. After this, the oxides grown on the Zy-4 sample surface were characterized using electrochemical measurements, gravimetric analysis, metallographic analysis, SEM and XPS. The maximum oxide thicknesses evaluated by gravimetric and SEM measurements were in good agreement; both values were around 1.2 µm. The optical light microscopy (OLM) investigations identified the presence of small hydrides uniformly distributed horizontally across the alloy. EIS impedance spectra showed an increase in the oxide impedance for the samples oxidized for a long time. EIS plots has the best fit with an equivalent circuit which illustrated an oxide model that has two oxide layers: an inner oxide layer and outer layer. The EIS results showed that the inner layer was a barrier layer, and the outer layer was a porous layer. Potentiodynamic polarization results demonstrated superior corrosion resistance of the samples tested for longer periods of time. By XPS measurements we identified all five oxidation states of zirconium: Zr0 located at 178.5 eV; Zr4+ at 182.8 eV; and the three suboxides, Zr+, Zr2+ and Zr3+ at 179.7, 180.8 and 181.8 eV, respectively. The determination of Vickers microhardness completed the investigation

The Influence of Processing Time on Morphology, Structure and Functional Properties of PEO Coatings on AZ63 Magnesium Alloy

The plasma electrolytic oxidation (PEO) surface modification technique was employed for improving the mechanical and anti-corrosion properties of the AZ63 magnesium alloy. Different PEO processing times (5, 10 and 20 min) in a 10 g/L NaAlO2 electrolyte, with no other additives, led to the formation of ceramic coatings with mean thicknesses between 15 and 37 microns. Scanning electron microscopy (SEM) showed that the porosity of the coatings decreased with processing time, but an increase in roughness was observed. X-Ray diffraction phase analysis indicated a coating structure composed of majority magnesium aluminate spinel. The corrosion rate of the coated samples decreased with an order of magnitude compared with the bare alloy. The average micro-hardness values of the PEO-coated samples was up to five times higher than those of the AZ63 alloy

The Influence of Processing Time on Morphology, Structure and Functional Properties of PEO Coatings on AZ63 Magnesium Alloy

The plasma electrolytic oxidation (PEO) surface modification technique was employed for improving the mechanical and anti-corrosion properties of the AZ63 magnesium alloy. Different PEO processing times (5, 10 and 20 min) in a 10 g/L NaAlO2 electrolyte, with no other additives, led to the formation of ceramic coatings with mean thicknesses between 15 and 37 microns. Scanning electron microscopy (SEM) showed that the porosity of the coatings decreased with processing time, but an increase in roughness was observed. X-Ray diffraction phase analysis indicated a coating structure composed of majority magnesium aluminate spinel. The corrosion rate of the coated samples decreased with an order of magnitude compared with the bare alloy. The average micro-hardness values of the PEO-coated samples was up to five times higher than those of the AZ63 alloy