Geochemistry, mineral paragenesis and geothermal conditions of oreforming fluids from the Ain El Bey Cu–Fe deposit: potential occurrence of native gold and precious metal traces (North African orogenic belt, Northern Tunisia)

The Ain El Bey abandoned mine, in North-West Tunisia, fits into the geodynamic context of the European and African plate boundary. Ore deposit corresponds to veins and breccia of multiphase Cu–Fe-rich mineralization related to various hydrothermal fluid circulations. Petromineralogical studies indicate a rich mineral paragenesis with a minimum of seven mineralization phases and, at least, six pyrite generations. As is also the case for galena and native silver, native gold is observed for the first time as inclusion in quartz which opens up, thus, new perspectives for prospecting and evaluating the potential for noble metals associated with the mineralization. Scanning Electron Microscope--Energy Dispersive Spectroscopy and Transmission electron microscopy analyses show, in addition, a large incorporation of trace elements, including Ag and Au, in mineral structures such as fahlores(tetrahedrite-tennantite) and chalcopyrite ones. The mineral/mineral associations, used as geothermometers, gave estimated temperatures for the mineralizing fluids varying from 254 to 330 ℃ for phase Ⅲ, from 254 to 350 ℃ for phase Ⅳ, and from 200 to 300 ℃ for phases Ⅴ and Ⅵ. The seventh and last identified mineralization phase, marked by a deposit of native gold, reflects a drop in the mineralizing fluid’s temperature(< 200 ℃) compatible with boiling conditions. Such results open up perspectives for the development of precious metal research and the revaluation of the Cu–Fe ore deposit at the Ain El Bey abandoned mine, as well as at the surrounding areas fitting in the geodynamic framework of the Africa-Europe plate boundary.

Antioxidant Potential of Four Species of Natural Product and Therapeutic Strategies for Cancer through Suppression of Viability in the Human Multiple Myeloma Cell Line U266

Objective This research aimed to evaluate the protective effects of bioactive compounds such as phenolic acids, flavonoids, and tannins present in four species extracted with methanol. Methods The total phenolic content of the methanolic extracts was measured spectrophotometrically. The effect of the extracts on cell viability in U266 cells was measured. The effects of extracts on free radical scavenging were assessed by the DPPH test and FRAP assay. Antibacterial effects of the natural products in this report were investigated by using the disc diffusion method. Results Our results clearly demonstrated that the methanolic extracts were characterized by a high amount of phenolic compounds. It has been speculated that ME-TA and ME-TAl exhibit a significant(P < 0.05) and dose-dependent antiradical potential. The exposure of cells to high doses of extracts almost completely suppressed cell growth in vitro. ME-TA and ME-TAl showed significant cytotoxic effects at a concentration of 100 μg/mL in the U266 cell line. ME-TAl and ME-CF inhibited the growth of B. subtilis and S. aureus, respectively, to the same extent as 10 μg/μL of chloramphenicol at a concentration of 1 mg/mL. Conclusion Overall, these results suggest that plants used in traditional medicine have a novel application as free radical scavengers, bacterial inhibitors and tumor suppressors.

Functionalization and Structural Characterization of a Novel Nacrite-LiCl Nanohybrid Material

The nacrite-LiCl hybrid composite material was prepared at room temperature by indirect inter-calation of lithium chloride between the planar layers of nacrite, a clay mineral, using acetone as a solvent. The structural identification of the hybrid clay material was determined by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA) and infrared spectroscopy (IR). The qualitative XRD analysis showed that the basal spacing value increased from 0.72 nm to 1.14 nm and revealed that the alkali halide intercalated successfully in the interlayer space of the nacrite framework. The quantitative XRD analysis allowed us to determine the optimum structural parameters related to the position and number of keyed ions and water molecules per half unit cell calculated along the c* axis and the goodness of fit parameter (Rp). The thermal properties of the elaborated hybrid were in great accordance with the XRD study and confirm the intercalation of the hydrated salt in the interlamellar space of nacrite. Moreover, IR spectroscopy enabled the study of the interactions between the silicate ‘‘networks’’ and the alkali halide.

Elaboration of Amorphous-Clay Hybrid: (Al₂Si₂O₇·1/2Li₂O) Designed as a Single Ion Conducting Solid Electrolyte for Li-Ion Batteries

Keying of lithium chloride alkali halide salt into the interlamellar space of nacrite clay mineral leads to a stable hybrid material that after calcination under inert atmosphere at 723 - 873 K induces an amorphous metahybrid. The electrochemical impedance spectroscopy (EIS) was performed to investigate the electric/dielectric properties of the hybrid with various parameters: frequency and temperature. Equivalent circuit was proposed to fit the EIS data. The experiment results show that the ionic conduction mechanism is related to the motion of Li+ cations which are thermally activated, named the hopping model. Furthermore, the resulting metahybrid obtained from dehydroxylation of the formal hybrid shows a superionic behavior with high ionic conductivity up to 10﹣2 S·m﹣1, good electrochemical stability and can be used as a solid electrolyte material for Li-ion batteries.