The functional materials based on natural zeolite （clinoptilolite）, TiO2-zeolite and Ag-TiO2-zeolite have been successfully synthesized by solid-state reaction in fast-hydrothermal conditions. The obtained functiona...The functional materials based on natural zeolite （clinoptilolite）, TiO2-zeolite and Ag-TiO2-zeolite have been successfully synthesized by solid-state reaction in fast-hydrothermal conditions. The obtained functional materials were investigated by X-ray diffraction （XRD）, FT-1R （Fourier transform infrared） spectroscopy, DRUV-VIS （diffuse reflectance ultraviolet-visible） spectroscopy, BET （Brunauer-Emmett-Teller） and SEM/EDX （scanning electron microscope/energy dispersive X-ray spectrometer） analyses. The XRD results indicated that the clinoptilolite structure has a good thermal stabilization after the fast-hydrothermal treatment. Also, the high specific surface area about 92.55 m^2.g^-1 was noticed for Ag-TiO2-zeolite functional material. The presence of dopants was evidenced from EDX spectra. The enhanced bactericidal activity of Ag-TiO2-zeolite catalyst is proved through damaging of Enterococcusfaecalis colonies under visible irradiation, at different material doses and irradiation times.展开更多
Objective： A direct-current, cold atmospheric-pressure air plasma microjet （PMJ） was performed to inactivate Staphylococcus aureus （S. aureus） and Enterococcusfaecalis （E. faecalis） in air. The process of steri...Objective： A direct-current, cold atmospheric-pressure air plasma microjet （PMJ） was performed to inactivate Staphylococcus aureus （S. aureus） and Enterococcusfaecalis （E. faecalis） in air. The process of sterilization and morphology of bacteria was observed. We wish to know the possible inactivation mechanisms of PMJ and explore a potential application in dental and other temperature sensitive treatment. Methods： In this study, we employed a direct current, atmospheric pressure, cold air PMJ to inactivate bacterias. Scanning electron microscopy was employed to evaluate the morphology of S. aureus and showed rupture of cell walls after the plasma treatment and Optical emission spectrum （OES） were used to understand the possible inactivation mechanisms of PMJ. Re- suits＂ The inactivation rates could reach 100% in 5 min. When the distance between the exit nozzle of the PMJ device and Petri dish was extended from 1 cm to 3 cm, effective inactivation was also observed with a similar inactivation curve. Conclusion： The inactivation of bacteria is attributed to the abundant reactive oxygen and nitrogen species, as well as ultroviolet radiation in the plasma. Different life spans and defensibilities of these killing agents may hold the key to understanding the different inactivation curves at different treatment distances.展开更多
The purpose of this study was to investigate the antibacterial activity of calcium hydroxide [Ca（OH）2] combined with chitosan solutions against Enterococcus faecalis-infected root canal dentin and the effect of this...The purpose of this study was to investigate the antibacterial activity of calcium hydroxide [Ca（OH）2] combined with chitosan solutions against Enterococcus faecalis-infected root canal dentin and the effect of this new intraca- nal medicament on the bond strength of RealSeal sealer to radicular dentin. An experimental intracanal medicament was prepared by mixing different concentrations of chitosan solution （25%, 50%, and 100%, W/V） to Ca（OH）2 powder. Antibacterial activity was evaluated and the total numbers of colony forming units were determined. Bonding ability of RealSeal sealer to radicular dentin was evaluated using push-out bond strength test. Data were analyzed using one-way analysis of variance （ANOVA） and Tukey＇s multiple comparison tests. We found that Ca（OH）2 combined with different concentrations of chitosan solutions showed better antibacterial activity than Ca（OH）2 mixed with saline, without significantly affecting the bond strength of RealSeal sealer to radicular dentin （P 〉 0.05）. The findings suggest that Ca（OH）2 combined with chitosan is a promising intracanal medicament and may be effective in endodontic therapy.展开更多
The disinfected bacteria will be a photoreactivation under the irradiation of the sunlight,and the light intensity plays an important role in the bacteria resurrection.The effect of light intensity on photoreactivatio...The disinfected bacteria will be a photoreactivation under the irradiation of the sunlight,and the light intensity plays an important role in the bacteria resurrection.The effect of light intensity on photoreactivation of Escherichia coli(E.coli) and Enterococcus faecalis(E.faecalis) in secondary effluents which were disinfected respectively by pure UV and UV-TiO_2 was investigated.The results show that the disinfection efficiency of UV-TiO_2 is much higher than that of the pure UV disinfection.The photoreactivation rate of E.coli is much higher in pure UV disinfection than in UV-TiO_2 photocatalytic disinfection.Under high light intensity in UV-TiO_2 disinfection,high resurrection rate can be induced.However,a higher resurrection rate can be introduced even under low light intensity in pure UV disinfection alone.Meanwhile,UV-TiO_2 disinfection has a strong inhibition effect on E.faecalis photoreactivation.When the light intensity is lower than 21 μW/cm^2,nearly no resurrection of E.faecalis occurs after 72 h resurrection irradiation,and a little resurrection rate is observed only under a strong photoreactivating light intensity.展开更多
基金Supported by the Sectoral Operational Programme Human Resources Development(SOP HRD)Financed from the European Social Fundthe Romanian Government under the Contract Number POSDRU/89/1.5/S/63700
文摘The functional materials based on natural zeolite （clinoptilolite）, TiO2-zeolite and Ag-TiO2-zeolite have been successfully synthesized by solid-state reaction in fast-hydrothermal conditions. The obtained functional materials were investigated by X-ray diffraction （XRD）, FT-1R （Fourier transform infrared） spectroscopy, DRUV-VIS （diffuse reflectance ultraviolet-visible） spectroscopy, BET （Brunauer-Emmett-Teller） and SEM/EDX （scanning electron microscope/energy dispersive X-ray spectrometer） analyses. The XRD results indicated that the clinoptilolite structure has a good thermal stabilization after the fast-hydrothermal treatment. Also, the high specific surface area about 92.55 m^2.g^-1 was noticed for Ag-TiO2-zeolite functional material. The presence of dopants was evidenced from EDX spectra. The enhanced bactericidal activity of Ag-TiO2-zeolite catalyst is proved through damaging of Enterococcusfaecalis colonies under visible irradiation, at different material doses and irradiation times.
基金supported by Bioelectrics Inc.(USA),Peking University Biomed-X Foundation and China International Science and Technology Cooperation(No.2008KR1330)
文摘Objective： A direct-current, cold atmospheric-pressure air plasma microjet （PMJ） was performed to inactivate Staphylococcus aureus （S. aureus） and Enterococcusfaecalis （E. faecalis） in air. The process of sterilization and morphology of bacteria was observed. We wish to know the possible inactivation mechanisms of PMJ and explore a potential application in dental and other temperature sensitive treatment. Methods： In this study, we employed a direct current, atmospheric pressure, cold air PMJ to inactivate bacterias. Scanning electron microscopy was employed to evaluate the morphology of S. aureus and showed rupture of cell walls after the plasma treatment and Optical emission spectrum （OES） were used to understand the possible inactivation mechanisms of PMJ. Re- suits＂ The inactivation rates could reach 100% in 5 min. When the distance between the exit nozzle of the PMJ device and Petri dish was extended from 1 cm to 3 cm, effective inactivation was also observed with a similar inactivation curve. Conclusion： The inactivation of bacteria is attributed to the abundant reactive oxygen and nitrogen species, as well as ultroviolet radiation in the plasma. Different life spans and defensibilities of these killing agents may hold the key to understanding the different inactivation curves at different treatment distances.
文摘The purpose of this study was to investigate the antibacterial activity of calcium hydroxide [Ca（OH）2] combined with chitosan solutions against Enterococcus faecalis-infected root canal dentin and the effect of this new intraca- nal medicament on the bond strength of RealSeal sealer to radicular dentin. An experimental intracanal medicament was prepared by mixing different concentrations of chitosan solution （25%, 50%, and 100%, W/V） to Ca（OH）2 powder. Antibacterial activity was evaluated and the total numbers of colony forming units were determined. Bonding ability of RealSeal sealer to radicular dentin was evaluated using push-out bond strength test. Data were analyzed using one-way analysis of variance （ANOVA） and Tukey＇s multiple comparison tests. We found that Ca（OH）2 combined with different concentrations of chitosan solutions showed better antibacterial activity than Ca（OH）2 mixed with saline, without significantly affecting the bond strength of RealSeal sealer to radicular dentin （P 〉 0.05）. The findings suggest that Ca（OH）2 combined with chitosan is a promising intracanal medicament and may be effective in endodontic therapy.
基金Projects(51174090,51168026)supported by the National Natural Science Foundation of China
文摘The disinfected bacteria will be a photoreactivation under the irradiation of the sunlight,and the light intensity plays an important role in the bacteria resurrection.The effect of light intensity on photoreactivation of Escherichia coli(E.coli) and Enterococcus faecalis(E.faecalis) in secondary effluents which were disinfected respectively by pure UV and UV-TiO_2 was investigated.The results show that the disinfection efficiency of UV-TiO_2 is much higher than that of the pure UV disinfection.The photoreactivation rate of E.coli is much higher in pure UV disinfection than in UV-TiO_2 photocatalytic disinfection.Under high light intensity in UV-TiO_2 disinfection,high resurrection rate can be induced.However,a higher resurrection rate can be introduced even under low light intensity in pure UV disinfection alone.Meanwhile,UV-TiO_2 disinfection has a strong inhibition effect on E.faecalis photoreactivation.When the light intensity is lower than 21 μW/cm^2,nearly no resurrection of E.faecalis occurs after 72 h resurrection irradiation,and a little resurrection rate is observed only under a strong photoreactivating light intensity.
