A novel method was developed for papain immobilization through a biomimetic silicification process induced by papain. By incubating papain in a silica precursor solution, the papain-silica composite formed rapidly and...A novel method was developed for papain immobilization through a biomimetic silicification process induced by papain. By incubating papain in a silica precursor solution, the papain-silica composite formed rapidly and oanain was encansulated. The encansulation efficiency and the recovery activity were 82.60% and 83.09%, re-spectively. Compared with enzymes and biomolecules immobilized in biosilica matrix in the presence of additaonal silica-precipitating species, this papaln encapsulation process, a biomimetic approach, realized high encapsulation efficiency by its autosilification activity under mild conditions （near-neutral pH and ambient temperature）. Fur-thermore, the encapsulated papain exhibits enhanced thermal, pH, recycling and storage stabilities. Kinetic analysis showed that the biomimetic silica matrix did not significantly hinder the mass transport of substrate or the release of product.展开更多
The effect of microwave （MW） heating on the dielectric properties and oxidation processes of virgin olive oil and refined sunflower oil were determined by dielectric and UV- spectroscopy. Samples were heated in the ...The effect of microwave （MW） heating on the dielectric properties and oxidation processes of virgin olive oil and refined sunflower oil were determined by dielectric and UV- spectroscopy. Samples were heated in the microwave oven （850 W, 2.450 MHz） for 0 to 14 minutes. The results show degradation of dielectric characteristics, conductivity and oxidative stability of investigated oils, increasing with the exposure time. UV spectrum shows only one defined peak at 206 nm for olive oil confirming the dominant presence of monounsaturated fats and four peaks for sunflower oil （203 nm, 230 nm, 269 nm and 278 nm） dependent on polyunsaturated acid fats contents. Increasing of absorbance at all peak wave lengths indicates production of lipid oxidation, due to formation of conjugated monoenes and dienes and in small amounts due to trienes and secondary products like ketoaldehydes. Dielectric constant for olive oil is stable and almost unchangeable with MW radiation while sunflower oil＇s c＇ oscillates around the origin value in greater rate. Dielectric loss e＂ decreases with increasing time of MW radiation and its maximum shifts towards higher frequencies for sunflower oil indicating shortening of the relaxation times, while for olive oil it is unchanged. Cole-Cole analysis show the presence of only one relaxation process in the oils. Conductivity of oils is increasing in similar way with increasing frequency following the Jonscher＇s power law and is not changed with MW exposure time. Olive oil has conductivity higher for four orders of magnitude than sunflower oil, which is connected to the high content of monounsaturated fats. The differences between sunflower and olive oil characteristics are discussed.展开更多
To increase the service life of rechargeable batteries,transition metal oxide hosts with high structural stability for the intercalation of carrier ions are important.Herein,we reconstruct the crystal structure of a c...To increase the service life of rechargeable batteries,transition metal oxide hosts with high structural stability for the intercalation of carrier ions are important.Herein,we reconstruct the crystal structure of a commercial V_(2)O_(5)by pre-intercalating H^(+)and H_(2)O pillars using a facile hydrothermal reaction and obtain a bi-layer structured H_(0.642)V_(2)O_(5)·0.143H_(2)O(HVO)as an excellent host for aqueous Zn-ion batteries.Benefiting from the structural reconstruction,the irreversible“layer-to-amorphous”phase evolution during cycling is considerably less,resulting in ultra-high cycling stability of HVO with nearly no capacity fading even after 500 cycles at a current density of 0.5Ag^(-1).Moreover,a synthetic proton and Zn^(2+)intercalation mechanism in the HVO host is demonstrated.This work provides both a facile synthesis method for the preparation of V-based compounds and a new viewpoint for achieving high-performance host materials.展开更多
基金Supported by the National Natural Science Foundation of China （21006020, 21276060, 21276062）, the Natural Science Foundation of Hebei Province （B2010000035, B2011202095）, the Science and Technology Research Key Project of Higher School in Hebei Province （ZD2010118）, the Application Basic Research Plan Key Basic Research Project of Hebei Province （11965150D） and Open Funding Project of ~e National Key Laboratory ofBiochemi＇cal Engineering （China）.
文摘A novel method was developed for papain immobilization through a biomimetic silicification process induced by papain. By incubating papain in a silica precursor solution, the papain-silica composite formed rapidly and oanain was encansulated. The encansulation efficiency and the recovery activity were 82.60% and 83.09%, re-spectively. Compared with enzymes and biomolecules immobilized in biosilica matrix in the presence of additaonal silica-precipitating species, this papaln encapsulation process, a biomimetic approach, realized high encapsulation efficiency by its autosilification activity under mild conditions （near-neutral pH and ambient temperature）. Fur-thermore, the encapsulated papain exhibits enhanced thermal, pH, recycling and storage stabilities. Kinetic analysis showed that the biomimetic silica matrix did not significantly hinder the mass transport of substrate or the release of product.
文摘The effect of microwave （MW） heating on the dielectric properties and oxidation processes of virgin olive oil and refined sunflower oil were determined by dielectric and UV- spectroscopy. Samples were heated in the microwave oven （850 W, 2.450 MHz） for 0 to 14 minutes. The results show degradation of dielectric characteristics, conductivity and oxidative stability of investigated oils, increasing with the exposure time. UV spectrum shows only one defined peak at 206 nm for olive oil confirming the dominant presence of monounsaturated fats and four peaks for sunflower oil （203 nm, 230 nm, 269 nm and 278 nm） dependent on polyunsaturated acid fats contents. Increasing of absorbance at all peak wave lengths indicates production of lipid oxidation, due to formation of conjugated monoenes and dienes and in small amounts due to trienes and secondary products like ketoaldehydes. Dielectric constant for olive oil is stable and almost unchangeable with MW radiation while sunflower oil＇s c＇ oscillates around the origin value in greater rate. Dielectric loss e＂ decreases with increasing time of MW radiation and its maximum shifts towards higher frequencies for sunflower oil indicating shortening of the relaxation times, while for olive oil it is unchanged. Cole-Cole analysis show the presence of only one relaxation process in the oils. Conductivity of oils is increasing in similar way with increasing frequency following the Jonscher＇s power law and is not changed with MW exposure time. Olive oil has conductivity higher for four orders of magnitude than sunflower oil, which is connected to the high content of monounsaturated fats. The differences between sunflower and olive oil characteristics are discussed.
基金supported by the Basic and Applied Basic Research Foundation of Guangdong Province(2019A1515110094).
文摘To increase the service life of rechargeable batteries,transition metal oxide hosts with high structural stability for the intercalation of carrier ions are important.Herein,we reconstruct the crystal structure of a commercial V_(2)O_(5)by pre-intercalating H^(+)and H_(2)O pillars using a facile hydrothermal reaction and obtain a bi-layer structured H_(0.642)V_(2)O_(5)·0.143H_(2)O(HVO)as an excellent host for aqueous Zn-ion batteries.Benefiting from the structural reconstruction,the irreversible“layer-to-amorphous”phase evolution during cycling is considerably less,resulting in ultra-high cycling stability of HVO with nearly no capacity fading even after 500 cycles at a current density of 0.5Ag^(-1).Moreover,a synthetic proton and Zn^(2+)intercalation mechanism in the HVO host is demonstrated.This work provides both a facile synthesis method for the preparation of V-based compounds and a new viewpoint for achieving high-performance host materials.
