Cu(II) and Fe(III) complexes of sulphadoxine mixed with pyramethamine: Synthesis, characterization, antimicrobial and toxicology study

Two new mixed ligands metal complexes of sulphadoxine and pyramethamine were prepared by using CuCl2.6H2O and FeCl3.6H2O. The complexes were characterized by elemental analysis, melting point determination, molar conductivity, metal content analysis (AAS), IR, magnetic susceptibility measurements and UV-Visible spectroscopy. Based on the analytical and spectroscopic data, the complexes were proposed to have the formulae [M1L1L2(Cl)2] and [M2L1L2(Cl)3] (where M1 = Cu(II), M2 = Fe(III)), L1 = sulphadoxine, L2 = pyramethamine). The spectroscopic data proposed L1 to be a monodentate ligand and coordinated through N atom of the NH2 group in both complexes. Also, L2 was proposed to be tridentate ligand and coordinated through N atom of the NH2 groups and through N atom of imine group. However, [M1L1L2(Cl)2] and [M2L1L2(Cl)3] were proposed to possess distorted octahedral geometry. Conductivity measurement values supported the non-electrolytic nature of the complexes. The complexes have been tested in vitro against a number of pathogenic bacteria [g(+) Escherichia coli, g(+) Proteus species, g(+) Pseudomonas aeruginosa and g(+) Salmonella typhi] by using disc diffusion method. Obtained results indicated that the metal complexes exhibited better antibacterial activities as compared to the ligands. Toxicology tests against some tissues of albino rat (Rattus novergicuss) revealed toxicity of the complexes in the kidney as compared to the parent drugs. [M1L1L2(Cl)2] was found to be toxic to the sera, livers and kidneys of the rats used, while [M2L1L2(Cl)3] was found to be non-toxic to the sera, livers and kidneys of the rats as their alkaline phosphatase (ALP) values showed non-significant difference to the control value

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 LaMnO3 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

Development of 3-Point Flexural Test Fixtures

In developing economies, the cost of acquiring laboratory testing equipment and accessories is huge, thereby depriving most of the supposedly advanced laboratories of most of this necessary research equipment. In this study, a 3-point flexural test accessory has been designed and developed for a universal mechanical testing equipment. The 3-piont flexural accessory is an important accessory in mechanical examination for the flexural strength of engineering materials. The computer aided design and modelling as well as the materials selection was done using Pro/engineer and Granta software. The material selected for the development of the components is austenitic stainless steel which is readily available and accessible in Nigerian market The developed flexural test accessory was used on the test equipment to conduct flexural tests on composite samples and the results were found to conform to international standard. Keywords: Mechanical, Flexural Test, accessory, Equipment, Design and Developmen

Combustion synthesis and characterization of Li1.2Mn0.52Ni0.20Co0.08O2 cathodes for Li-Ion battery: Effect of fuel mixture and annealing temperature

The effect of fuel mixture and annealing temperature on the structural properties and electrochemical performance of Li1.20Mn0.52Ni0.20Co0.08O2 powders prepared by the combustion synthesis were studied. Different combinations of citric acid fuel and ammonium acetate along with post-temperature treatments could be used to control the product characteristics. Simultaneous thermal analyses and thermodynamic modelling were used to describe the combustion processes. The analysis of the XRD data and other reports showed that the synthesis method and chemical compositions of lithium-rich layered oxides (LLO) could influence their description either as a solid solution or a ‘composite’ structure. The annealing temperature greatly influenced the lattice parameters, unit cell volumes, crystallite sizes, and cationic disorder of the samples whilst the use of fuel mixture had little effect. Furthermore, the electrochemical performances of the cathode materials were studied and the relationship with the structural properties of the powder samples were analysed. The Li1.20Mn0.52Ni0.20Co0.08O2 powders synthesized with only citric acid fuel (100-T) displayed the best electrochemical performance compared with those produced using the fuel mixtures. The enhanced electrochemical performance of the 100-T cathodes was shown to be an integrative property of the highest values reported for their structural properties. The results show that citric acid assisted combustion and annealing temperature (mostly with pre-annealing) could be used to optimize the electrochemical performance of LLO cathode material

Experimental and Theoretical Studies of (E)-N'-1-(4- propylbenzylidene)nicotinohydrazide as Corrosion Inhibitor of Mild Steel in 1 M HC

The efficiency of a novel Schiff base namely (E)-N'-1-(4-propylbenzylidene)nicotinohydrazide (PBNH) was investigated as corrosion inhibitor of mild steel (MS) in 1M HCl using weight loss technique at 303 and 313 K. It was established that corrosion rate of mild steel increases with increase in temperature and concentration of HCl. Results showed that PBNH considerably inhibited the corrosion of mild steel in a 1 M HCl solution and inhibition efficiency is about 70% at 4 × 10–4 M PBNH at both temperatures. The inhibi� tion efficiency of PBNH increased with an increase in concentration and temperature. The adsorption model obeys the Langmuir adsorption isotherm and the kinetic–thermodynamic model and the value of free energy of adsorption, indicated that the adsorption of PBNH was a spontaneous process and was both an elec� trostatic�adsorption (physisorption) and adsorption on the basis of donor�acceptor interactions (chemisorp�tion). Thermodynamic parameters calculated show the spontaneity and endothermic nature of the process and also reveal the favourable affinity of PBNH towards the mild steel surface. Quantum chemical calcula�tions based on PM3 method was performed on PBNH and calculated parameters gave useful information to explain the interaction between the surface of metal and PBNH

Silica Functionalized Magnesium Ferrite Nanocomposites for Potential Biomedical Applications: Preparation, Characterization and Enhanced Colloidal Stability Studies

Magnetic nanocomposite material composed of silica coated MgFe2O4 for potential biomedical applications were synthesized by a two-step chemical method including solution combustion synthesis, followed by silica coatings of the ferrite nanoparticles. The effects of silica coatings on the structural, morphological and magnetic properties were comprehensively investigated using powder X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), energy dispersive absorption x-ray (EDAX), Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric analysis and differential thermal analysis (TG–DTA) and vibrating sample magnetometer (VSM). The colloidal behaviour of coated MNPs in physiological saline medium like water or phosphate buffer saline (PBS) was also studied by zeta potential measurements. The XRD patterns indicate that the crystalline structure is single cubic spinel phase and the spinel structure is retained after silica coating. Also, after silica coating, the crystallite size (from Scherrer formula) decreases from 53 to 47 nm. The magnetic results show that MgFe2O4 MNPs (bare and silica coated) is ferrimagnetic at room temperature. Zeta potential studies revealed that there is enhanced colloidal stability of MgFe2O4 MNPs after silica coating in aqueous media which is an applicable potential in biomedical application

The effect of polyol on multiple ligand capped silver alloyed nanobimetallic particles in tri-n-octylphosphine oxide and oleic acid matrices

The syntheses of Ag/M (M is Co, Ni, Pd, Pt and Ru) alloyed nanobimetallic particles in tri-noctylphosphine oxide and oleic acid matrices were successfully carried out by the successive reduction of ligand capped metal ions with polyols, which resulted in rapid precipitation of some fractal high index faceted hybrid Ag/M bimetal nanoparticles. The optical measurements revealed the existence of modified surface plasmon band and peak broadening resulting from reaction-limited growth processes of the metal sols, making it possible to monitor the changes spectrometrically. The bimetallic nanoparticles were further characterized by powder x-ray diffraction, x-ray photoelectron spectroscopy and electron microscopy techniques which confirmed the formation of novel core–shell and alloyed clusters. The Ag/M nanoparticles thus synthesized within TOPO/OA matrices indicated significant reduction potential as a result of their energy band gap 2.65–2.77 eV which points to the fact that they could serve as reducing agents for electrocatalytic reaction

Tandem Synthesis of some Low and High Indexed Monometallic Nanoparticles in Polyols, Poly(Vinylpyrrolidone), Trisodium Citrate and Dodecanethiol Matrices

Sequential synthesis of some noble metal nanoparticles was successfully carried out by polyol/borohydride or hydrazine reduction in the presence of poly(vinylpyrrolidone), trisodium citrate and dodecanethiol in non-aqueous and aqueous solutions with concomitant precipitation of some high index faceted nanoparticles. The polyols afforded Pt NPs as small as 3.5 nm in diameter, which gradually (over a period of months) self-assembled into nanorods that were 5-6 nm in width and 20-30 nm in length. The formation of low indexed Pt NPs species occurred only at moderate temperature, but Pd high indexed face-centered cubic structures formed at 160 °C, while Co formed high indexed nanodiscs at 190 °C with an average diameter of 11.23 nm. The process could be monitored by UV absorption spectrophotometer, powder x-ray diffractometer and transmission electron microscopy (TEM). The polyol was indeed multifunctional: it reduced M+ (Co2+, Ni2+, Ru3+, Pd2+, Pt4+), stabilized the obtained M0 species and served as a template for the tandem formation of monometallic NPs of different morphology

Evaluating the diesel biodegradation potential of wild microfungi isolat-ed from decaying wood in Nigeria

We evaluated the potentials of pure wild microfungi isolated from decaying wood in utilizing diesel as source of carbon/energy and monitoring of their physiological responses via OD and pH gradient fluxes. The fungi diversity was obtained by conventional enrichment culture methods. Pure cultures of tentative fungal species namely: SC1, SC2, SC3, YI and Y2 were tested for their ability to utilize diesel oil as carbon and energy source. From the cultur-al, morphological and biochemical characterization and comparison with respect to the standard reference of fungi, the wild microfungi tentatively named as SC1, SC2, SC3, YI and Y2 were seemingly the members of Penicil-lum, Aspergillus, Mucor, Candida and Cryptococcus species. The diesel de-pendent growth of the pure microfungi was assessed by monitoring the flux-es in the pH and Optical density OD of the minimal media slurry for 288 hours. There were fluctuations in OD as well as pH values for the different microfungi. The mean pH data 5.90 ± 0.01-7.01± 0.01 and the OD 0.349± 0.001 -1.232 ± 0.002 were obtained. The ability of our fungal isolates to tol-erate diesel and grow in it, suggests that the isolates can be employed as bioremediation agent