The development of aquaculture in Nigeria is constrained by the inadequate supply of high quality of fingerlings of African catfish(Clarias gariepinus).There are conflicting reports on the reproductive efficacy of Ver...The development of aquaculture in Nigeria is constrained by the inadequate supply of high quality of fingerlings of African catfish(Clarias gariepinus).There are conflicting reports on the reproductive efficacy of Vernonia amygdalina when compared with the synthetic hormone Ovaprim(OV)and Pituitary Extract(PE)on C.gariepinus.The histopathology of select organs in catfish treated with generic Ovaprim(OV),Pituitary Extract(CPE),and aqueous extract of Vernonia amygdalina(VAE)were evaluated.Sixteen female C.gariepinus(average weight of 1 kg)wereevenly and randomly distributed to four groups.Fish in groups A,B,C,and D were injected intramuscularly with aqueous solutions of OV(0.5 mL/kg),PE(5 mg/kg),VAE(10 mg/kg),and distilled water(DW;0.5 ml),respectively.Histological examinations of the ovary,liver,kidney,and spleen were carried out.Histopathology revealed that OV-and PE-treated groups showed synchronous and synchronous ovarian development,vacuolar change of hepatocytes,thinning of hepatic cords,reduced renal haemopoietic compartments,tubular degeneration and necrosis,and decrease in splenic periarteriolar lymphoid sheaths(PALS).VAE-treated groups had asynchronous ovarian development with atretic ovarian follicles,widespread vacuolar change of hepatocytes,intact renal tubular and hemopoietic compartments,and preponderance of large and coalescing splenic PALS.We conclude that VAE is an ineffective spawning agent,especially when compared with OV and PE,as VAE could not induce synchronous gonadal development.However,VAE may have immunopotentiating,nephroprotective,and haemopoietic properties.展开更多
Graphene Oxide (GO) was chemically synthesized from Natural Flake Graphite (NFG). The GO was chemically reduced to Reduced Graphene Oxide (RGO) using hydrazine monohydrate. Thin films of GO and RGO were also deposited...Graphene Oxide (GO) was chemically synthesized from Natural Flake Graphite (NFG). The GO was chemically reduced to Reduced Graphene Oxide (RGO) using hydrazine monohydrate. Thin films of GO and RGO were also deposited on sodalime glass substrate using spray pyrolysis technique (SPT). The samples were characterized using Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray (EDS) facility attached to it, UV-Visible Spectrometry and Four-Point probe. The FTIR spectra showed the addition of oxygen functionality groups in GO while such groups was drastically reduced in RGO. SEM micrograph of GO thin film showed a porous sponge-like structure while the micrograph of RGO thin film showed evenly distributed and well connected graphene structure. The EDX spectrum of RGO showed that there was decrease in oxygen content and increase in carbon content of RGO when compared to GO. The optical analysis of the GO and RGO thin films gave a direct energy bandgap of 2.7 eV and 2.2 eV respectively. The value of sheet resistance of GO and RGO films was determined to be 22.9 × 10<sup>6</sup>Ω/sq and 4.95 × 10<sup>6</sup>Ω/sq respectively.展开更多
Molybdenum oxodithiocarbamate was prepared as thin films which were deposited on sodalime glass a single solid source precursor for molybdenum oxysulphide substrates using metal organic chemical vapour deposition （MO...Molybdenum oxodithiocarbamate was prepared as thin films which were deposited on sodalime glass a single solid source precursor for molybdenum oxysulphide substrates using metal organic chemical vapour deposition （MOCVD） technique at a temperature of 420~C. Rutherford backscattering spectroscopy （RBS） was used to determine the elemental composition of the film which showed that the films contained large amounts of oxygen. The large amount of oxygen was attributed to the large abundance of oxygen in the starting material. A direct optical energy gap of 3.31 eV was obtained from the analysis of the absorption spectrum. The scanning electron microscopy （SEM） micrographs of the films showed that the films were continuous and porous. An estimated average size of the grains was below 5 #m. X-ray diffraction （XRD） showed that the deposited films were crystalline in nature.展开更多
Mesoporous ceramic membranes were prepared from raw and modified diatomaceous earth alumi-nosilicate mineral precursors. The main modification component of the ceramic membranes was Ag-loaded TiO<sub>2</sub&g...Mesoporous ceramic membranes were prepared from raw and modified diatomaceous earth alumi-nosilicate mineral precursors. The main modification component of the ceramic membranes was Ag-loaded TiO<sub>2</sub> nanoparticles (STOX). Chemical and microstructural characterizations of the raw materials and the modified precursors were carried out using Fourier Transform Infrared (FTIR) Spectroscopy, Particle Induced X-ray Emission (PIXE-IBA), Energy Dispersive X-ray Spectroscopy (EDX) and Scanning Electron Microscopy (SEM). The precursors and membranes were prepared and subsequently subjected to a high temperature sintering treatment for physico-chemical modification and stability. Remediation functionalities of the ceramic membranes on water samples were studied using Atomic Absorption Spectrophotometry (AAS), Total Bacterial Count Enumeration;Total Dissolved Solids (TDS), pH, and Electroconductivity (EC). Remediation experiments showed reductions in the concentration of certain cations such as Mg<sup>2+</sup>, Mn<sup>2+</sup>, Cd<sup>2+</sup>, Ni<sup>2+</sup> and K<sup>+</sup> by the modified ceramic membrane samples, while increased concentrations were observed for Ca<sup>2+</sup>, Na<sup>+</sup> and Mg<sup>2+</sup>. The antimicrobial microfiltration process showed 100% bacterial removal and 70% fungi removal in most of the samples. Membranes exhibited good flux output from 5.607 L/hr·m<sup>2</sup> (STOX-Z) to 39.245 L/hr·m<sup>2</sup> (ZEO-T) under a pressure of 0.0196 MPa.展开更多
文摘The development of aquaculture in Nigeria is constrained by the inadequate supply of high quality of fingerlings of African catfish(Clarias gariepinus).There are conflicting reports on the reproductive efficacy of Vernonia amygdalina when compared with the synthetic hormone Ovaprim(OV)and Pituitary Extract(PE)on C.gariepinus.The histopathology of select organs in catfish treated with generic Ovaprim(OV),Pituitary Extract(CPE),and aqueous extract of Vernonia amygdalina(VAE)were evaluated.Sixteen female C.gariepinus(average weight of 1 kg)wereevenly and randomly distributed to four groups.Fish in groups A,B,C,and D were injected intramuscularly with aqueous solutions of OV(0.5 mL/kg),PE(5 mg/kg),VAE(10 mg/kg),and distilled water(DW;0.5 ml),respectively.Histological examinations of the ovary,liver,kidney,and spleen were carried out.Histopathology revealed that OV-and PE-treated groups showed synchronous and synchronous ovarian development,vacuolar change of hepatocytes,thinning of hepatic cords,reduced renal haemopoietic compartments,tubular degeneration and necrosis,and decrease in splenic periarteriolar lymphoid sheaths(PALS).VAE-treated groups had asynchronous ovarian development with atretic ovarian follicles,widespread vacuolar change of hepatocytes,intact renal tubular and hemopoietic compartments,and preponderance of large and coalescing splenic PALS.We conclude that VAE is an ineffective spawning agent,especially when compared with OV and PE,as VAE could not induce synchronous gonadal development.However,VAE may have immunopotentiating,nephroprotective,and haemopoietic properties.
文摘Graphene Oxide (GO) was chemically synthesized from Natural Flake Graphite (NFG). The GO was chemically reduced to Reduced Graphene Oxide (RGO) using hydrazine monohydrate. Thin films of GO and RGO were also deposited on sodalime glass substrate using spray pyrolysis technique (SPT). The samples were characterized using Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray (EDS) facility attached to it, UV-Visible Spectrometry and Four-Point probe. The FTIR spectra showed the addition of oxygen functionality groups in GO while such groups was drastically reduced in RGO. SEM micrograph of GO thin film showed a porous sponge-like structure while the micrograph of RGO thin film showed evenly distributed and well connected graphene structure. The EDX spectrum of RGO showed that there was decrease in oxygen content and increase in carbon content of RGO when compared to GO. The optical analysis of the GO and RGO thin films gave a direct energy bandgap of 2.7 eV and 2.2 eV respectively. The value of sheet resistance of GO and RGO films was determined to be 22.9 × 10<sup>6</sup>Ω/sq and 4.95 × 10<sup>6</sup>Ω/sq respectively.
基金the Third World Academy of Science (TWAS,No.93-058R6/PHYS/AF/AC) Italy and Obafemi Awolowo University (University Research Committee (URC)) for support-ing this project
文摘Molybdenum oxodithiocarbamate was prepared as thin films which were deposited on sodalime glass a single solid source precursor for molybdenum oxysulphide substrates using metal organic chemical vapour deposition （MOCVD） technique at a temperature of 420~C. Rutherford backscattering spectroscopy （RBS） was used to determine the elemental composition of the film which showed that the films contained large amounts of oxygen. The large amount of oxygen was attributed to the large abundance of oxygen in the starting material. A direct optical energy gap of 3.31 eV was obtained from the analysis of the absorption spectrum. The scanning electron microscopy （SEM） micrographs of the films showed that the films were continuous and porous. An estimated average size of the grains was below 5 #m. X-ray diffraction （XRD） showed that the deposited films were crystalline in nature.
文摘Mesoporous ceramic membranes were prepared from raw and modified diatomaceous earth alumi-nosilicate mineral precursors. The main modification component of the ceramic membranes was Ag-loaded TiO<sub>2</sub> nanoparticles (STOX). Chemical and microstructural characterizations of the raw materials and the modified precursors were carried out using Fourier Transform Infrared (FTIR) Spectroscopy, Particle Induced X-ray Emission (PIXE-IBA), Energy Dispersive X-ray Spectroscopy (EDX) and Scanning Electron Microscopy (SEM). The precursors and membranes were prepared and subsequently subjected to a high temperature sintering treatment for physico-chemical modification and stability. Remediation functionalities of the ceramic membranes on water samples were studied using Atomic Absorption Spectrophotometry (AAS), Total Bacterial Count Enumeration;Total Dissolved Solids (TDS), pH, and Electroconductivity (EC). Remediation experiments showed reductions in the concentration of certain cations such as Mg<sup>2+</sup>, Mn<sup>2+</sup>, Cd<sup>2+</sup>, Ni<sup>2+</sup> and K<sup>+</sup> by the modified ceramic membrane samples, while increased concentrations were observed for Ca<sup>2+</sup>, Na<sup>+</sup> and Mg<sup>2+</sup>. The antimicrobial microfiltration process showed 100% bacterial removal and 70% fungi removal in most of the samples. Membranes exhibited good flux output from 5.607 L/hr·m<sup>2</sup> (STOX-Z) to 39.245 L/hr·m<sup>2</sup> (ZEO-T) under a pressure of 0.0196 MPa.
