A. Edobor-Osoh

Facile Synthesis and Characterization of New 2,3-Disubstituted Benzimidazole Derivatives

Benzimidazoles are known to represent a class of medicinally i mportant compounds which are extensively used as antibacterial agents. Hence, a series of five 2

Low-temperature solution-combustion synthesis and magneto-structural characterization of polycrystalline La1–xAgyMnO3 (y ≤ x) manganites

Silver is known to be a highly mobile (low-soluble) component in Ag-doped perovskite manganites and hence several non-perovskite phases can exist in silver doped manganite perovskites with most synthetic routes making its synthesis to be problematic. In search of soft synthesis route, the low temperature combustion synthesis and magneto-structural studies of polycrystalline La1–xAgyMnO3 (y ≤ x) ceramic manganites using glycine as a fuel is reported. The sintered powders were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDAX) analysis, Thermo Gravimetric Analysis (TGA) and Vibrating Scanning Magnetometer (VSM) measurements. XRD patterns showed formation of mainly single rhombohedral perovskite phase for the La0.8Ag0.15MnO3 sample and an admixture of secondary phases with La0.8Ag0.1MnO3 and La0.8Ag0.2MnO3 samples. The distinct microstructure and higher magnetic properties observed for La0.8Ag0.15MnO3 sample compared to the other samples were discussed based on the XRD results.

Structural, morphological and magnetic properties of La1−xNayMnO3 (y ≤ x) nanoparticles produced by the solution combustion method

The rapid solution combustion synthesis and characterization of sodium (Na)-substituted LaMnO 3 phases at relatively low temperature using polyvinyl alcohol (PVA) as fuel were reported. The thermal decomposition process investigated by means of differential and thermal gravimetric analysis (TG–DTA) showed that the use of PVA as a fuel was satisfactory in the synthesis of the perovskite manganite compound. Structural study using X-ray diffraction showed that all the samples were single phasic without any detectable impurities within the measurement range. Also, the Na-substituted compounds crystallize with rhombohedral symmetry (space group R-3c, no. 167) with La0.80Na0.15MnO3 manganite sample giving the highest crystallinity. Microstructural features observed by field-emission scanning electron microscopy demonstrated that most of the grains were nearly spherical in shape with fairly uniform distribution and all the observed particles connect with each other. Energy-dispersive X-ray analyses confirm the homogeneity of the samples. Increase in magnetic moment was observed with the increase in sodium doping. Room-temperature vibrating sample magnetometer measurements showed that the samples were ferromagnetic with compositions y = 0.10, 0.15 and 0.20 showing relatively high magnetic moments of 33, 34 and 36 emu g−1, respectively.

Solutions of the Klein-Gordon equation with equal scalar and vector harmonic oscillator plus inverse quadratic potential

The solutions of the Klein-Gordon equation with equal scalar and vector harmonic oscillator plus inverse quadratic potential for S-waves have been presented using the Nikiforov-Uvarov method. The bound state energy eigenvalues and the corresponding un-normalized eigenfunctions are obtained in terms of the Laguerre polynomials.

Assessment of Trace Metal Levels in Fish Species of Lagos Lagoon

Fish species, surface water, bottom water, epipellic and benthic sediments were collected from Oworonshoki, Lagos lagoon, to determine their trace metal levels using atomic absorption spectrophotometer. The fish species collected were Tilapia guineensis, Chrysichthys nigrodigitatus, Liza grandisquamis and Psettias sebae. The results indicated that the highest concentrations of trace metals were present in the fish species, followed by benthic sediments, epipellic sediments, bottom water, and surface water. Levels of trace metals found in males and females of fish species showed significant differences. The female species, except Tilapia guineensis, accumulated higher Fe and Zn values. The female species of Psettias sebae was a good bio-indicator of trace metal contamination in the lagoon. Cd and Ni were not detected in any of the fish species. Pb levels in the fishes were above the maximum acceptable limit for human consumption, and could have been sourced from the discharge of industrial wastes into the lagoon. The levels of Fe and Zn in the water, sediment and fishes were all within acceptable limits. The highest condition factor of 2.76 was observed in the female of Chrysichthys nigrodigitatus, while the female, Psettias sebae, had the least condition factor of 0.57, correlating with its high metal contamination.

Magneto-Structural and Antimicrobial Properties of Sodium Doped Lanthanum Manganite Magnetic Nanoparticles for Biomedical Applications: Influence of Silica Coating

Coating of magnetic nanoparticles (MNPs) is usually a requirement prior to their utilization in biomedical applications. However, coating can influence the magneto-structural properties of MNPs thereby imparting their applications. The present work highlights the combustion synthesis of Na-doped lanthanum manganites (LNMO) and the influence of silica coatings on the magneto-structural properties, colloidal stability and antimicrobial properties of LNMO MNPs with their biomedical applications in mind. The crystalline perovskite structure was the same both for the bare and silica coated LNMO samples while there was a slight increase in crystallite size after coating. The FTIR spectral analysis, reduction in agglomeration of the particles and the elemental composition of the coated nanoparticles confirmed the presence of silica. The magnetization values of 34 emu/g and 29 emu/g recorded for bare and coated LNMO samples, respectively show that LNMO MNPs retained its ferromagnetic behaviour after silica coating. The pH dependent zeta potentials of the coated sample is-22.20 mV at pH 7.4 (physiological pH) and-18 mV at pH 5.0 (cell endosomal pH). Generally, silica coating reduced the antibacterial activity of the sample except for Bacillus spp where the antibacterial activity was the same with the bare sample. These results showed that while silica coating had marginal effect on the crystalline structure, size and magnetization of LNMO MNPs, it reduced the antibacterial activity of LNMO MNPs and enhanced greatly the colloidal stability of LNMO nanoparticles. Keywords: Na-doped lanthanum manganites, Silica coating, magnetic nanoparticles, biomedical applications, antimicrobial properties, colloidal stability

Solutions of the Schrödinger equation with inversely quadratic effective plus Mie-type potential using Nikiforov-Uvarov method

The Schrodinger equation with the interaction of inversely quadratic effective and Mie-type potential has been solved for any angular momentum quantum number l using the Nikiforov-Uvarov method. The bound state energy eigenvalues and the corresponding un-normalized eigenfunctions are obtained in terms of the Laguerre polynomials. Several cases of the potential are also considered and their eigen values obtained.

Solutions of the Schrödinger equation with inversely quadratic Hellmann plus inversely quadratic potential using Nikiforov-Uvarov method

By using the Nikiforov-Uvarov (NU) method, the Schrodinger equation has been solved for the interaction of inversely quadratic Hellmann (IQHP) and inversely quadratic potential (IQP) for any angular momentum quantum number, l. The energy eigenvalues and their corresponding eigenfunctions have been obtained in terms of Laguerre polynomials. Special cases of the sum of these potentials have been considered and their energy eigenvalues also obtained.