Search

The main objectives of the current study were synthesis and characterization of zinc oxide nanoparticles (ZnONPs) using the aqueous leaf extract of Guazuma ulmifolia (G. ulmifolia)plant and assessing its antimicrobial and antioxidant potential. The nanoparticles were characterized using Ultraviolet Visible (UV–Vis), Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Energy-dispersive X-ray (EDS) and Scanning electron microscopy (SEM). ZnONPs exhibited a maximum peak at 342 nm in the UV–Vis spectrum, indicating their absorption properties. FTIR analysis confirmed the presence of functional groups, such as OH and COOH which likely contributed to the stability of the nanoparticles. The XRD analysis confirmed the spherical structure of the nanoparticles as indicated by distinct diffraction peaks corresponding to the lattice planes of the ZnO standard. The EDS analysis confirmed the presence of Zn, C and O in the ZnONPs. SEM analysis provided insights into the nanoparticles size, shape and surface morphology, showing an average size between 19 and 41 nm. Furthermore, the synthesized ZnONPs demonstrated excellent antioxidant and antibacterial activities against various bacteria and Candidaspecies. This study highlights the promising potential of ZnONPs in diverse fields, including biomedicine, due to their low toxicity, economic viability and beneficial properties. It is crucial to conduct further in vivo investigations in order to determine the safety, effectiveness and compatibility of G. ulmifoliaZnONPs.

The stability of a Boussinesq fluid-saturated horizontal porous layer, heated from below, is examined for the case of a time-dependent wall temperature. Forchheimer flow model with effective viscosity larger than the viscosity of the fluid is considered to give a more general theoretical result. A method based on small amplitude of the modulation proposed by Venezian (1969, J. Fluid Mech., 30, 243-254) is used to compute the critical values of the Rayleigh number and wave number. The shift in the critical Rayleigh number is calculated as a function of frequency of modulation, Prandtl number, porous parameter, and viscosity ratio. It is shown that the system is most stable when the boundary temperature is modulated out of phase. It is also found that the low-frequency thermal modulation can have a significant effect on the stability of the system. The effect of the viscosity ratio and Prandtl number on the stability of the system is also brought out.