Allium cepa bioassay had been used from decades for the assessment of toxicants and their harmful effects on environment as well as human health. Magnesium oxide（MgO） particles are being utilized in different fields...Allium cepa bioassay had been used from decades for the assessment of toxicants and their harmful effects on environment as well as human health. Magnesium oxide（MgO） particles are being utilized in different fields. However, reports on the adverse effects of MgO nanoparticles on the environment and mankind are scarce. Hence, the toxicity of MgO particles is of concern because of their increased utilization. In the current study, A. cepa was used as an indicator to assess the toxicological efficiency of MgO nano-and microparticles（NPs and MPs） at a range of exposure concentrations（12.5, 25, 50, and100 μg/m L）. The toxicity was evaluated by using various bioassays on A. cepa root tip cells such as comet assay, oxidative stress and their uptake/internalization profile. Results indicated a dose dependent increase in chromosomal aberrations and decrease in mitotic index（MI） when compared to control cells and the effect was more significant for NPs than MPs（at p 〈 0.05）. Comet analysis revealed that the Deoxyribonucleic acid（DNA） damage in terms of percent tail DNA ranged from 6.8–30.1 over 12.5–100 μg/m L concentrations of MgO NPs and was found to be significant at the exposed concentrations. A significant increase in generation of hydrogen peroxide and superoxide radicals was observed in accordance with the lipid peroxidation profile in both MgO NPs and MPs treated plants when compared with control. In conclusion, this investigation revealed that MgO NPs exposure exhibited greater toxicity on A. cepa than MPs.展开更多
The aim of this study was to test the antimicrobial properties of dental cements modified with magnesium oxide(MgO)nanoparticles.Zein-modified MgO nanoparticles(zMgO)in concentrations(0.0,0.3,0.5,and 1.0%)were mixed w...The aim of this study was to test the antimicrobial properties of dental cements modified with magnesium oxide(MgO)nanoparticles.Zein-modified MgO nanoparticles(zMgO)in concentrations(0.0,0.3,0.5,and 1.0%)were mixed with dental cements(Fuji II,Rely X Temp E,Ionoglass Cem,Es Temp NE,and System P link).Eight discs were fabricated from each zMgO-cement pair for a total of 32 specimens for each cement.Characterization of the dental cements incorporating zMgO was done by X-ray Diffraction(XRD)and Field Emission Scanning Electron Microscopy(FESEM).The antimicrobial properties of the mixtures were tested using direct contact and agar diffusion assays against Streptococcus mutans,Staphylococcus aureus,Enterococcus faecalis,and Candida albicans.Data was analyzed using two-way analysis of variance and LSD post hoc test at 0.05 significance level.XRD spectra showed sharp peaks of zMgO indicating its high crystalline nature,while the amorphous dental cements with zMgO had broad peaks.FESEM analysis showed a uniform distribution of the zMgO nanoparticles in the cement.There were significant inhibition zone values associated with all concentrations of zMgO-cement mixtures tested compared to controls(p<0.001)with a dose-response recorded only with Fuji II.Optical density values were significantly lower in zMgO groups compared to controls for all microorganisms.The effect was most prominent with Rely X against C.albicans and S.aureus.Dental cements containing zMgO showed significant antimicrobial properties that were dependent on the specific initial cement substrate.展开更多
The formation of protective multifunctional coatings on magnesium alloy MA8 using plasma electrolyt- ic oxidation （PEO） in an electrolytic system containing nanosized particles of titanium nitride was investigated. ...The formation of protective multifunctional coatings on magnesium alloy MA8 using plasma electrolyt- ic oxidation （PEO） in an electrolytic system containing nanosized particles of titanium nitride was investigated. Electrochemical and mechanical properties of the obtained layers were examined. It was established that microhardness of the coating with the nanoparticle concentration of 3 gl-1 increased twofold （4.2 ± 0.5 GPa）, while wear resistance decreased （4.97 × 10-6 mm3 N-1 m-1）, as compared to re- spective values for the PEO-coating formed in the electrolyte without nanoparticles （2.1 ± 0.3 GPa, 1.12 × 10.5 mm3 N-1 m-1）.展开更多
基金the Director IICT, Hyderabad for providing funds and facility to execute this study
文摘Allium cepa bioassay had been used from decades for the assessment of toxicants and their harmful effects on environment as well as human health. Magnesium oxide（MgO） particles are being utilized in different fields. However, reports on the adverse effects of MgO nanoparticles on the environment and mankind are scarce. Hence, the toxicity of MgO particles is of concern because of their increased utilization. In the current study, A. cepa was used as an indicator to assess the toxicological efficiency of MgO nano-and microparticles（NPs and MPs） at a range of exposure concentrations（12.5, 25, 50, and100 μg/m L）. The toxicity was evaluated by using various bioassays on A. cepa root tip cells such as comet assay, oxidative stress and their uptake/internalization profile. Results indicated a dose dependent increase in chromosomal aberrations and decrease in mitotic index（MI） when compared to control cells and the effect was more significant for NPs than MPs（at p 〈 0.05）. Comet analysis revealed that the Deoxyribonucleic acid（DNA） damage in terms of percent tail DNA ranged from 6.8–30.1 over 12.5–100 μg/m L concentrations of MgO NPs and was found to be significant at the exposed concentrations. A significant increase in generation of hydrogen peroxide and superoxide radicals was observed in accordance with the lipid peroxidation profile in both MgO NPs and MPs treated plants when compared with control. In conclusion, this investigation revealed that MgO NPs exposure exhibited greater toxicity on A. cepa than MPs.
基金funded by Deanship of Scientific Research(DSR),King Abdulaziz University,Jeddah,Saudi Arabia,under grant No.(DF-044-165-1441).
文摘The aim of this study was to test the antimicrobial properties of dental cements modified with magnesium oxide(MgO)nanoparticles.Zein-modified MgO nanoparticles(zMgO)in concentrations(0.0,0.3,0.5,and 1.0%)were mixed with dental cements(Fuji II,Rely X Temp E,Ionoglass Cem,Es Temp NE,and System P link).Eight discs were fabricated from each zMgO-cement pair for a total of 32 specimens for each cement.Characterization of the dental cements incorporating zMgO was done by X-ray Diffraction(XRD)and Field Emission Scanning Electron Microscopy(FESEM).The antimicrobial properties of the mixtures were tested using direct contact and agar diffusion assays against Streptococcus mutans,Staphylococcus aureus,Enterococcus faecalis,and Candida albicans.Data was analyzed using two-way analysis of variance and LSD post hoc test at 0.05 significance level.XRD spectra showed sharp peaks of zMgO indicating its high crystalline nature,while the amorphous dental cements with zMgO had broad peaks.FESEM analysis showed a uniform distribution of the zMgO nanoparticles in the cement.There were significant inhibition zone values associated with all concentrations of zMgO-cement mixtures tested compared to controls(p<0.001)with a dose-response recorded only with Fuji II.Optical density values were significantly lower in zMgO groups compared to controls for all microorganisms.The effect was most prominent with Rely X against C.albicans and S.aureus.Dental cements containing zMgO showed significant antimicrobial properties that were dependent on the specific initial cement substrate.
基金financially supported by the Russian Science Foundation(Project No.14-33-00009)the Russian Federation Government(Federal Agency of Scientific Organizations)
文摘The formation of protective multifunctional coatings on magnesium alloy MA8 using plasma electrolyt- ic oxidation （PEO） in an electrolytic system containing nanosized particles of titanium nitride was investigated. Electrochemical and mechanical properties of the obtained layers were examined. It was established that microhardness of the coating with the nanoparticle concentration of 3 gl-1 increased twofold （4.2 ± 0.5 GPa）, while wear resistance decreased （4.97 × 10-6 mm3 N-1 m-1）, as compared to re- spective values for the PEO-coating formed in the electrolyte without nanoparticles （2.1 ± 0.3 GPa, 1.12 × 10.5 mm3 N-1 m-1）.
