The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension ...The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension was then aged at room temperature for various periods of time. White precipitate was finally collected by centrifuging and washed with distilled water and anhydrous ethanol. The obtained cerium dioxide (CeO2) precursor was observed with SEM. It was found that the morphology and size of the precursor were strongly affected by aging time and stirring conditions (with or without stirring). The precipitated fine spherical particles of the precursor changed their shape from ellipse to slice or directly to slice. Fine spherical monodispersed (300 nm) precursor powders could be obtained by controlling the aging time. Stirring the solution also could change the reaction process and thus the morphology and size of the precursor were changed.展开更多
AIM: To investigate the apoptotic effect of photoexcited titanium dioxide (TiO2) nanoparticles in the presence of visible light on human hepatoma cell line (Bel 7402) and to study the underlying mechanism. METHODS: Ce...AIM: To investigate the apoptotic effect of photoexcited titanium dioxide (TiO2) nanoparticles in the presence of visible light on human hepatoma cell line (Bel 7402) and to study the underlying mechanism. METHODS: Cerium-element-doped titanium dioxide nanoparticles were prepared by impregnation method. Bel 7402 human hepatoma cells were cultured in RPMI 1640 medium in a humidified incubator with 50 mL/L CO2 at 37℃. A 15 W fluorescent lamp with continuous wavelength light was used as light source in the photocatalytic test. Fluorescence morphology and agarose gel eletrophoresis pattern were performed to analyze apoptotic cells. RESULTS: The Ce (Ⅳ)-doped TiO2 nanoparticles displayed their superiority. The adsorption edge shifted to the 400-450 nm region. With visible light illuminated for 10 min, 10 μg/cm3 Ce (Ⅳ)-doped TiO2 induced micronuclei and significant apoptosis in 4 and 24 h, respectively. Hochest 33 258 staining of the fixed cells revealed typical apoptotic structures (apoptotic bodies), agarose gel electrophoresis showed typical DNA ladder pattern in treated cells but not in untreated ones. CONCLUSION: Ce (Ⅳ) doped TiO2 nanoparticles can induce apoptosis of Bel 7402 human hepatoma cells in the presence of visible light.展开更多
Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generat...Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generated by metal vacuum arc (MEVVA) and radio frequency (RF) is discussed in this paper. We have recently conducted a systematic investigation to determine the optimal process window to deposit CeO2 thin films'on Si(100) substrates. The X-ray diffraction results show the existence of CeO2(100) in the as-deposited sample.展开更多
The use of fillers to enhance the corrosion protection of epoxy resins has been widely applied.In this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion res...The use of fillers to enhance the corrosion protection of epoxy resins has been widely applied.In this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion resistance of Q235 carbon steel.Scanning electron microscopy results indicated that the CeO_(2) grains were rod-like and ellipsoidal in shape,and the distribution pattern of BTA was analyzed by energy dispersive spectroscope.The dynamic potential polarization curve proved the excellent corrosion resistance of the composite epoxy resin with CeO_(2) and BTA co-addition,and electrochemical impedance spectroscopy test analysis indicated the significantly enhanced long-term corrosion protection performance of the composite coating.And the optimal protective performance was provided by the coating containing 0.3%(mass)CeO_(2) and 20%(mass)BTA,which was attributed to the barrier performance of CeO_(2) particles and the chemical barrier effect of BTA.The formation of corrosion products was analyzed using X-ray diffraction.In addition,the corrosion resistance mechanism of the coating was also discussed in detail.展开更多
Reactive oxygen species(ROS)plays important roles in living organisms.While ROS is a double-edged sword,which can eliminate drug-resistant bacteria,but excessive levels can cause oxidative damage to cells.A core–shel...Reactive oxygen species(ROS)plays important roles in living organisms.While ROS is a double-edged sword,which can eliminate drug-resistant bacteria,but excessive levels can cause oxidative damage to cells.A core–shell nanozyme,Ce O_(2)@ZIF-8/Au,has been crafted,spontaneously activating both ROS generating and scavenging functions,achieving the multifaceted functions of eliminating bacteria,reducing inflammation,and promoting wound healing.The Au Nanoparticles(NPs)on the shell exhibit high-efficiency peroxidase-like activity,producing ROS to kill bacteria.Meanwhile,the encapsulation of Ce O_(2) core within ZIF-8 provides a seal for temporarily limiting the superoxide dismutase and catalase-like activities of Ce O_(2) nanoparticles.Subsequently,as the ZIF-8 structure decomposes in the acidic microenvironment,the Ce O_(2) core is gradually released,exerting its ROS scavenging activity to eliminate excess ROS produced by the Au NPs.These two functions automatically and continuously regulate the balance of ROS levels,ultimately achieving the function of killing bacteria,reducing inflammation,and promoting wound healing.Such innovative ROS spontaneous regulators hold immense potential for revolutionizing the field of antibacterial agents and therapies.展开更多
In this work,we prepared a material with magnetic nanoparticles(Fe_(3)O_(4))as core,layered double hydroxides(LDHs)as affinity shell,and cerium dioxide(CeO_(2))as functional molecules(denoted as Fe_(3)O_(4)@LDH-CeO_(2...In this work,we prepared a material with magnetic nanoparticles(Fe_(3)O_(4))as core,layered double hydroxides(LDHs)as affinity shell,and cerium dioxide(CeO_(2))as functional molecules(denoted as Fe_(3)O_(4)@LDH-CeO_(2)).On the basis of combined immobilized metal ion affinity chromatography(IMAC)and metal oxide affinity chromatography(MOAC),Fe_(3)O_(4)@LDH-CeO_(2) was used to enrich phosphopeptides with high efficiency.The material exhibited high selectivity(α-casein:β-casein:BSA=1:1:5000,mass ratio),high recovery(95.87%),and good reusability of 10 times adsorption-desorption experiments.The feasibility of Fe_(3)O_(4)@LDH-CeO_(2) was further investigated by extracting phosphopeptides from biological samples(nonfat milk,serum,saliva,and A549 cell lysate).展开更多
基金the Natural Science Foundation of Jiangsu Province under pro ject No.BK2002010.
文摘The synthesis of ultrafine cerium dioxide precursor via homogeneous precipitation was studied. Mixed aqueous solution of anhydrous cerium nitrate and urea was first heated to 85℃ for 2 h, and the prepared suspension was then aged at room temperature for various periods of time. White precipitate was finally collected by centrifuging and washed with distilled water and anhydrous ethanol. The obtained cerium dioxide (CeO2) precursor was observed with SEM. It was found that the morphology and size of the precursor were strongly affected by aging time and stirring conditions (with or without stirring). The precipitated fine spherical particles of the precursor changed their shape from ellipse to slice or directly to slice. Fine spherical monodispersed (300 nm) precursor powders could be obtained by controlling the aging time. Stirring the solution also could change the reaction process and thus the morphology and size of the precursor were changed.
文摘AIM: To investigate the apoptotic effect of photoexcited titanium dioxide (TiO2) nanoparticles in the presence of visible light on human hepatoma cell line (Bel 7402) and to study the underlying mechanism. METHODS: Cerium-element-doped titanium dioxide nanoparticles were prepared by impregnation method. Bel 7402 human hepatoma cells were cultured in RPMI 1640 medium in a humidified incubator with 50 mL/L CO2 at 37℃. A 15 W fluorescent lamp with continuous wavelength light was used as light source in the photocatalytic test. Fluorescence morphology and agarose gel eletrophoresis pattern were performed to analyze apoptotic cells. RESULTS: The Ce (Ⅳ)-doped TiO2 nanoparticles displayed their superiority. The adsorption edge shifted to the 400-450 nm region. With visible light illuminated for 10 min, 10 μg/cm3 Ce (Ⅳ)-doped TiO2 induced micronuclei and significant apoptosis in 4 and 24 h, respectively. Hochest 33 258 staining of the fixed cells revealed typical apoptotic structures (apoptotic bodies), agarose gel electrophoresis showed typical DNA ladder pattern in treated cells but not in untreated ones. CONCLUSION: Ce (Ⅳ) doped TiO2 nanoparticles can induce apoptosis of Bel 7402 human hepatoma cells in the presence of visible light.
基金The work was supported by Hong Kong RGC CERG9040344 and 9040412, RGC / Germany Joint Schemes9050084 and 9050150, and CityU S
文摘Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generated by metal vacuum arc (MEVVA) and radio frequency (RF) is discussed in this paper. We have recently conducted a systematic investigation to determine the optimal process window to deposit CeO2 thin films'on Si(100) substrates. The X-ray diffraction results show the existence of CeO2(100) in the as-deposited sample.
基金financially supported by the National Natural Science Foundation of China(22178242)the Shanxi Provincial Key Research and Development Project(202102040201009).
文摘The use of fillers to enhance the corrosion protection of epoxy resins has been widely applied.In this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion resistance of Q235 carbon steel.Scanning electron microscopy results indicated that the CeO_(2) grains were rod-like and ellipsoidal in shape,and the distribution pattern of BTA was analyzed by energy dispersive spectroscope.The dynamic potential polarization curve proved the excellent corrosion resistance of the composite epoxy resin with CeO_(2) and BTA co-addition,and electrochemical impedance spectroscopy test analysis indicated the significantly enhanced long-term corrosion protection performance of the composite coating.And the optimal protective performance was provided by the coating containing 0.3%(mass)CeO_(2) and 20%(mass)BTA,which was attributed to the barrier performance of CeO_(2) particles and the chemical barrier effect of BTA.The formation of corrosion products was analyzed using X-ray diffraction.In addition,the corrosion resistance mechanism of the coating was also discussed in detail.
基金supported by the Natural Science Foundation of Fujian Province of China(No.2022J01043)China Scholarship Council(201806315005 and 201703170071).
文摘Reactive oxygen species(ROS)plays important roles in living organisms.While ROS is a double-edged sword,which can eliminate drug-resistant bacteria,but excessive levels can cause oxidative damage to cells.A core–shell nanozyme,Ce O_(2)@ZIF-8/Au,has been crafted,spontaneously activating both ROS generating and scavenging functions,achieving the multifaceted functions of eliminating bacteria,reducing inflammation,and promoting wound healing.The Au Nanoparticles(NPs)on the shell exhibit high-efficiency peroxidase-like activity,producing ROS to kill bacteria.Meanwhile,the encapsulation of Ce O_(2) core within ZIF-8 provides a seal for temporarily limiting the superoxide dismutase and catalase-like activities of Ce O_(2) nanoparticles.Subsequently,as the ZIF-8 structure decomposes in the acidic microenvironment,the Ce O_(2) core is gradually released,exerting its ROS scavenging activity to eliminate excess ROS produced by the Au NPs.These two functions automatically and continuously regulate the balance of ROS levels,ultimately achieving the function of killing bacteria,reducing inflammation,and promoting wound healing.Such innovative ROS spontaneous regulators hold immense potential for revolutionizing the field of antibacterial agents and therapies.
基金National Natural Science Foundation of China(Nos.22004073 and 21961024)Natural Science Foundation of Inner Mongolia,China(No.2020BS02010)+2 种基金Talent Research Support Funds from Government-Sponsored Institution of Inner Mongolia,China(No.RCQD19002)Inner Mongolia Minzu University Doctoral Research Startup Fund Project,China(No.BS516)Incentive Funding from Nano Innovation Institute(NII)of Inner Mongolia Minzu University,China.
文摘In this work,we prepared a material with magnetic nanoparticles(Fe_(3)O_(4))as core,layered double hydroxides(LDHs)as affinity shell,and cerium dioxide(CeO_(2))as functional molecules(denoted as Fe_(3)O_(4)@LDH-CeO_(2)).On the basis of combined immobilized metal ion affinity chromatography(IMAC)and metal oxide affinity chromatography(MOAC),Fe_(3)O_(4)@LDH-CeO_(2) was used to enrich phosphopeptides with high efficiency.The material exhibited high selectivity(α-casein:β-casein:BSA=1:1:5000,mass ratio),high recovery(95.87%),and good reusability of 10 times adsorption-desorption experiments.The feasibility of Fe_(3)O_(4)@LDH-CeO_(2) was further investigated by extracting phosphopeptides from biological samples(nonfat milk,serum,saliva,and A549 cell lysate).
