Investigation of the Photoluminescence and Nonlinear Optical Properties of Ce2O3-TiO2 Nanocomposites.

This paper reports the photoluminescence and nonlinear optical (NLO) properties of Ce2O3-TiO2 nanocomposites synthesized via sol-gel process with different concentrations of cerium. The physical characterization studies by means of XRD indicated for the successful incorporation of Ce into the lattice of TiO2, while the UV-visible spectra for an absorption edge shift of TiO2 to the higher wavelength side following the Ce addition, and FESEM analysis for the morphology and particles sizes of the synthesized materials. On testing of the photoluminescence properties recorded through time-resolved fluorescence (TCSPC) technique, a decrease in the intensity of TiO2 with that of increased Ce concentration was observed and is due to an escalation in the number of oxygen vacancies. Further, the observation NLO properties for Ce2O3-TiO2 was done by a Z-scan technique of 5ns continuous wave (cw) laser at 532 nm, where the involvement of active mechanisms in the nonlinear refraction and nonlinear absorption are due to the saturable absorption (SA) and nonlinear thermal effects.

Synthesis of Iron Oxide@Pt Core-Shell Nanoparticles for Reductive Conversion of Cr(VI) to Cr(III) and Antibacterial Studies.

Herein, we report the facile synthesis of Iron oxide@Pt core-shell nanoparticles (NPs) by facile two step synthesis process. The first step follows the growth of iron oxide nanoparticle by thermal decomposition process while the second step deals with the formation of iron oxide@Pt core-shell nanoparticles by the chemical reduction method. The synthesized core-shell nanoparticles were characterized by several techniques and used for the catalytic reductive translation of Cr(VI) to Cr(III) in the presence of formic acid by a UV-vis spectrophotometer. The UV photo-spectrometer analysis confirmed the conversion efficiency from 12% to as high as 98.8% at the end of 30 minutes. Thus, the presence of Iron oxide @Pt core-shell nanoparticles (NPs) can be effectively used as a catalyst for the reducion of Cr(VI) to Cr(III) ions. Additionally, antibacterial studies were performed for the prepared core-shell nanoparticles against two bacterial strains, i.e., gram (+ve) Staphylococcus Aureus (S. Aureus) and gram (-ve) Escherichia Coli (E. Coli).

Surfactant Assisted Hydroxyapatite Nanoparticles: Drug Loading and In Vitro Leaching Kinetics and Antimicrobial Properties.

In the present investigation, extremely fine Hydroxyapatite (HAP) powder was prepared through chemical precipitation technique under the influence of a nonionic surfactant (Brij 35-Polyoxyethylene lauryl ether). The samples were sintered at 800 °C to obtain highly pure HAP phase. The functional group present in the HAP powder was confirmed by using Fourier transform infra-red (FTIR) spectroscopy. The change in Phase transformation, the crystallite size and the percentage of crystallinity of the synthesized sample were studied by X-ray diffractometer technique. The Field Emission Scanning Electron Microscope (FESEM) and High-resolution transmission electron microscopy (HRTEM) were used for the structural analysis of porous rod-shaped HAP crystal. Further, drug loading and In Vitro leaching kinetics were conducted for antibiotics-ciproflaxin (CPF). Antimicrobial activity against S. aureus (Gram-positive bacterium) and E. coli (Gram-negative bacterium) was executed for pure HAP as well as for drug loaded HAP.