TiO_2 sols modified by rare earth (RE) ions (Ce^(4+), Eu^(3+), or Nd^(3+))were prepared by coprecipitation-peptization method. The photocatalysis activity was studied byinvestigating the photodegradation effects of ac...TiO_2 sols modified by rare earth (RE) ions (Ce^(4+), Eu^(3+), or Nd^(3+))were prepared by coprecipitation-peptization method. The photocatalysis activity was studied byinvestigating the photodegradation effects of active brilliant red dye X-3B. It is found that TiO_2sols modified by Ce^(4+), Eu^(3+), or Nd^(3+) have the anatase crystalline structure, which areprepared at 70℃. All RE^(n+)-TiO_2 sol samples have uniform nanoparticles with similar morphology,which are homogenously distributed in aqueous colloidal systems. The particle sizes are 10, 8, and12 nm for Nd^(3+)-TiO_2, Eu^(3+)-TiO_2, and Ce^(4+)-TiO_2, respectively. The character of ultrafineand positive charge sol particles contributes to the good adsorption of X-3B dye molecule on thesurface of titania (about 30% X-3B adsorption amount). Experimental results exhibit thatRE^(n+)-TiO_2 sol photocatalysts have the capability to photodegrade X-3B under visible lightirradiation. Nd^(3+)-TiO_2 and Eu^(3+)-TiO_2 show higher photocatalytic activity than Ce^(4+)-TiO_2,which is due to the difference of standard redox potential of RE^(n+)/RE^((n-1)+). RE^(n+)-TiO_2sols demonstrate more excellent interfacial adsorption and photodegradation effects to X-3B thanP_(25) TiO_2 crystallites. Moreover, the degradation mechanism of X-3B is proposed as dyephotosensitization and electron scavenging by rare earth ions.展开更多
The effects of rare earth ions on bone resorbing function of osteoclasts were studied by culturing Japanese white rabbit osteoclasts on bone slices. In order to evaluate the activity of osteoclasts, the number and sur...The effects of rare earth ions on bone resorbing function of osteoclasts were studied by culturing Japanese white rabbit osteoclasts on bone slices. In order to evaluate the activity of osteoclasts, the number and surface areas of lacunae were measured by photomicrography and image analysis, and the calcium concentration in the supernatant was measured by the atomic absorption spectrometry. The lacunae morphology was observed under a scanning electron microscope. The results indicated that La3+, Sm3+ and Er3+ at the concentration of 1.00?0-5, 1.00?0-6 and 1.00?10-7mol/L and Nd3+, Gd3+ and Dy3+ at the concentration of 1.00?10-5 and 1.00?0-6 mol/L inhibited osteoclastic activity as indicated by the dose-dependent reduction in the numbers and surface areas of the lacunae (P<0.01). On the contrary, the number and surface areas of lanunae were increased and osteoclastic bone resorbing function was significantly enhanced by La3+, Sm3+ and Er3+ at the concentration of 1.00?0-8 mol/L and Nd3+, Gd3+ and Dy3+ at the concentration of 1.00?0-7 mol/L (P<0.01). Nd3+, Gd3+ and Dy3+ had no effect on osteoclastic bone resorption function at concentrations as low as 1.00?0-8 mol/L (P>0.05). It is suggested that the effects of rare earth ions on osteoclastic bone resorption are bidirectional, depending on concentrations and species.展开更多
The effect of rare earth ion Er 3+ on myoglobin(Mb) was studied by using Resonance Raman spectroscopy. The results show that with the variation of Er 3+ concentrations, both the oxidation state and spin state of Mb ar...The effect of rare earth ion Er 3+ on myoglobin(Mb) was studied by using Resonance Raman spectroscopy. The results show that with the variation of Er 3+ concentrations, both the oxidation state and spin state of Mb are sensitive to the perturbation of Er 3+ . Er 3+ added to Mb affects the oxidation and spin state synchronously. The structure sensitive groups of Mb are more accessible to the Er 3+ than other groups. According to the fluorometry and CD spectra studied and our results as mentioned above, we considered that Er 3+ does not interact with heme directly, and Er 3+ probably leads to the conformational changes of Mb due to the change of oxidation and spin state of Heme. [WT5HZ]展开更多
基金This work was financially supported by the Hi-Tech Research and Development Program (863 Program) of China (No. 2002AA302304)the National Natural Science Foundation of China (No. 60121101)the Education Department Foundation of Jiangsu Province (JHOl-
文摘TiO_2 sols modified by rare earth (RE) ions (Ce^(4+), Eu^(3+), or Nd^(3+))were prepared by coprecipitation-peptization method. The photocatalysis activity was studied byinvestigating the photodegradation effects of active brilliant red dye X-3B. It is found that TiO_2sols modified by Ce^(4+), Eu^(3+), or Nd^(3+) have the anatase crystalline structure, which areprepared at 70℃. All RE^(n+)-TiO_2 sol samples have uniform nanoparticles with similar morphology,which are homogenously distributed in aqueous colloidal systems. The particle sizes are 10, 8, and12 nm for Nd^(3+)-TiO_2, Eu^(3+)-TiO_2, and Ce^(4+)-TiO_2, respectively. The character of ultrafineand positive charge sol particles contributes to the good adsorption of X-3B dye molecule on thesurface of titania (about 30% X-3B adsorption amount). Experimental results exhibit thatRE^(n+)-TiO_2 sol photocatalysts have the capability to photodegrade X-3B under visible lightirradiation. Nd^(3+)-TiO_2 and Eu^(3+)-TiO_2 show higher photocatalytic activity than Ce^(4+)-TiO_2,which is due to the difference of standard redox potential of RE^(n+)/RE^((n-1)+). RE^(n+)-TiO_2sols demonstrate more excellent interfacial adsorption and photodegradation effects to X-3B thanP_(25) TiO_2 crystallites. Moreover, the degradation mechanism of X-3B is proposed as dyephotosensitization and electron scavenging by rare earth ions.
基金supported by the National Natural Science Foundation of China(Grant No.20031010).
文摘The effects of rare earth ions on bone resorbing function of osteoclasts were studied by culturing Japanese white rabbit osteoclasts on bone slices. In order to evaluate the activity of osteoclasts, the number and surface areas of lacunae were measured by photomicrography and image analysis, and the calcium concentration in the supernatant was measured by the atomic absorption spectrometry. The lacunae morphology was observed under a scanning electron microscope. The results indicated that La3+, Sm3+ and Er3+ at the concentration of 1.00?0-5, 1.00?0-6 and 1.00?10-7mol/L and Nd3+, Gd3+ and Dy3+ at the concentration of 1.00?10-5 and 1.00?0-6 mol/L inhibited osteoclastic activity as indicated by the dose-dependent reduction in the numbers and surface areas of the lacunae (P<0.01). On the contrary, the number and surface areas of lanunae were increased and osteoclastic bone resorbing function was significantly enhanced by La3+, Sm3+ and Er3+ at the concentration of 1.00?0-8 mol/L and Nd3+, Gd3+ and Dy3+ at the concentration of 1.00?0-7 mol/L (P<0.01). Nd3+, Gd3+ and Dy3+ had no effect on osteoclastic bone resorption function at concentrations as low as 1.00?0-8 mol/L (P>0.05). It is suggested that the effects of rare earth ions on osteoclastic bone resorption are bidirectional, depending on concentrations and species.
文摘The effect of rare earth ion Er 3+ on myoglobin(Mb) was studied by using Resonance Raman spectroscopy. The results show that with the variation of Er 3+ concentrations, both the oxidation state and spin state of Mb are sensitive to the perturbation of Er 3+ . Er 3+ added to Mb affects the oxidation and spin state synchronously. The structure sensitive groups of Mb are more accessible to the Er 3+ than other groups. According to the fluorometry and CD spectra studied and our results as mentioned above, we considered that Er 3+ does not interact with heme directly, and Er 3+ probably leads to the conformational changes of Mb due to the change of oxidation and spin state of Heme. [WT5HZ]
