Complexation and interaction between silver and amino group were applied to induce an efficient immobilization of papain on silica spheres.Tbe silver nanoparticles were deposited on the silica spheres before p apainwa...Complexation and interaction between silver and amino group were applied to induce an efficient immobilization of papain on silica spheres.Tbe silver nanoparticles were deposited on the silica spheres before p apainwas coupled to the silica spheres. The silica spheres with silver nanoparticles were characterized by high resolution transmission electron microscopy （HR-TEM）, Fournier transform infrared spectroscopy （FT-IR）, and UV-Vis scanning spectrometer. FT-IR spectrum was also used to characterize the immobilized and free papain. Effect of some factors on the activities of the immobilized papain was investigated. It was observed that the coupled yield and relative activity of the papain on Ag/SiO2 were 1.17 and 1.86 times of those on the bare SiO2, respectively. At an optimum concentration of silver, theobserved activity of the immobilized papain was 2.1 timesof that on the bare.silica.In addition, the maximum specific activity of papain immobilized on Ag/SiO2 was 819.9 U·mg·^-1, which is slightly lower than that of the free papain, 906.2 U·mg^-1 . Stability of the immobilized papain was also examined. The resuits indicate that the silver nanoparticles successfully induce a fine immobilization of papain.展开更多
[SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃ for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied...[SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃ for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO]FePt]5/Ag films are changed into L10 and （111） mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controlling SiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 （0.6 nm）/FePt （3 nm）]5/Ag （50 nm） films and highly （001）-oriented films can be obtained in the [SiO2 （2 nm）/FePt （3 nm）]5/Ag （50 nm） films.展开更多
Six kinds of terbium ternary complexes with halo-benzoic acids were synthesized. Their compositions were determined by C, H elemental analyzer and EDTA titration. The infrared spectra, ultraviolet absorption spectra, ...Six kinds of terbium ternary complexes with halo-benzoic acids were synthesized. Their compositions were determined by C, H elemental analyzer and EDTA titration. The infrared spectra, ultraviolet absorption spectra, and fluorescence spectra were also measured to identify the complexes. Elemental analysis showed that the compositions of these complexes were Tb（p-BrBA）3- H20, Tb（p-CIBA）3- 2H20, Tb（p-FBA）3- H20, Tb（o-FBA）3·2H20, Tb（o-CIBA）3· H20, and Tb（o-BrBA）3. H20, respectively. The monodispersed Ag@SiO2 core-shell nanoparticles with silica thicknesses of 10, 15, and 25 nm were success- fully prepared and characterized by transmission-electron microscopy. Fluorescence intensities of the complexes were detected before and after Ag@SiO2core-shell nanoparticles were added; the enhancement times were related to the silica-shell thick- ness. The fluorescence enhancement times were largest when the thickness of the silica shell was 25 nm. The mechanism may be attributed to the localized surface-plasmon resonance. Furthermore, the enhancement effect of terbium fluoro-benzoate complexes was the strongest in these complexes. This result may be attributed to the hydrogen bond between the hydroxyl on the surface of the silica shell and the fluorine atom.展开更多
基金Supported by the National High Technology Research and Development Program of China （2006AA02Z211）, the National Natural Science Foundation of China （20376034）, the Natural Science Foundation of Jiangsu Province （BK2006181）, and the Foundation of Jiangsu Province for College Postgraduate Students in Innovation Engineering （2007）.
文摘Complexation and interaction between silver and amino group were applied to induce an efficient immobilization of papain on silica spheres.Tbe silver nanoparticles were deposited on the silica spheres before p apainwas coupled to the silica spheres. The silica spheres with silver nanoparticles were characterized by high resolution transmission electron microscopy （HR-TEM）, Fournier transform infrared spectroscopy （FT-IR）, and UV-Vis scanning spectrometer. FT-IR spectrum was also used to characterize the immobilized and free papain. Effect of some factors on the activities of the immobilized papain was investigated. It was observed that the coupled yield and relative activity of the papain on Ag/SiO2 were 1.17 and 1.86 times of those on the bare SiO2, respectively. At an optimum concentration of silver, theobserved activity of the immobilized papain was 2.1 timesof that on the bare.silica.In addition, the maximum specific activity of papain immobilized on Ag/SiO2 was 819.9 U·mg·^-1, which is slightly lower than that of the free papain, 906.2 U·mg^-1 . Stability of the immobilized papain was also examined. The resuits indicate that the silver nanoparticles successfully induce a fine immobilization of papain.
基金Project(10574085) supported by the National Natural Science Foundation of ChinaProject(207020) supported by the Science Technology Key Project of the Ministry of Education, China
文摘[SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃ for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO]FePt]5/Ag films are changed into L10 and （111） mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controlling SiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 （0.6 nm）/FePt （3 nm）]5/Ag （50 nm） films and highly （001）-oriented films can be obtained in the [SiO2 （2 nm）/FePt （3 nm）]5/Ag （50 nm） films.
基金supported by the National Natural Science Foundation of China(21161013)the Natural Science Foundation of Inner Mongolia(2011MS0202)the Opening Foundation for Significant Fundamental Research of Inner Mongolia(2010KF03)
文摘Six kinds of terbium ternary complexes with halo-benzoic acids were synthesized. Their compositions were determined by C, H elemental analyzer and EDTA titration. The infrared spectra, ultraviolet absorption spectra, and fluorescence spectra were also measured to identify the complexes. Elemental analysis showed that the compositions of these complexes were Tb（p-BrBA）3- H20, Tb（p-CIBA）3- 2H20, Tb（p-FBA）3- H20, Tb（o-FBA）3·2H20, Tb（o-CIBA）3· H20, and Tb（o-BrBA）3. H20, respectively. The monodispersed Ag@SiO2 core-shell nanoparticles with silica thicknesses of 10, 15, and 25 nm were success- fully prepared and characterized by transmission-electron microscopy. Fluorescence intensities of the complexes were detected before and after Ag@SiO2core-shell nanoparticles were added; the enhancement times were related to the silica-shell thick- ness. The fluorescence enhancement times were largest when the thickness of the silica shell was 25 nm. The mechanism may be attributed to the localized surface-plasmon resonance. Furthermore, the enhancement effect of terbium fluoro-benzoate complexes was the strongest in these complexes. This result may be attributed to the hydrogen bond between the hydroxyl on the surface of the silica shell and the fluorine atom.
