A new,facile,and efficient way to prepare alkalinized g-C3N4 is presented.We calcined a mixture of KCl and melamine to obtain g-C3N4,whose in-plane structure was K+doped so that alkalinized samples could be obtained b...A new,facile,and efficient way to prepare alkalinized g-C3N4 is presented.We calcined a mixture of KCl and melamine to obtain g-C3N4,whose in-plane structure was K+doped so that alkalinized samples could be obtained by treatment with different concentrations of KOH.The different samples were used to oxidize As(Ⅲ)in both visible light and natural light.The sample treated with 10 mol/L KOH showed the highest efficiency,converting all As(Ⅲ)into As(Ⅴ)within 120 min in both visible light and natural light,as the oxidative capacity of the As(Ⅲ)in the alkalinized samples was significantly higher than that of the original samples.K+doping improved the electron transport capacity of the samples,while the alkalinized samples could destroy their edge structures,so as to improve the separation efficiency of the photogenerated carrier.The experiment confirmed that alkalinized g-C3N4 significantly improves the oxidation ability of As(Ⅲ)and plays an important role in the photocatalytic treatment of refractory nonmetallic ions.展开更多
Element doping is a simple and effective method to improve photocatalytic activity of g-C3N4. However, the doping model and mechanism of metal elements are still uncharacterized. In this study, we found that Fe(Ⅲ) ca...Element doping is a simple and effective method to improve photocatalytic activity of g-C3N4. However, the doping model and mechanism of metal elements are still uncharacterized. In this study, we found that Fe(Ⅲ) can be doped into g-C3N4 through the coordination between amidogen and Fe(Ⅲ). After activity tests, it was found that this coordination doping of Fe(Ⅲ) could enhance the Rh B oxidation and Cr(Ⅵ) reduction activities of g-C3N4 in interesting ways, but it is not helpful for the NO-removal performance of g-C3N4. Characterization and calculation results show that the coordination of Fe(Ⅲ) can not only improve the transfer of photogenerated electrons, but it also can passivate the carbon site of triazine rings, which is the active site of NO-removal. This study revealed some doping mechanisms and effect mechanisms of elemental metal in photocatalysis.展开更多
Early pregnancy factor (EPF) was purified from the pooled sera of 21 0 pregnant women at 3- 8 weeks of gestation. Sera from healthy nonpregnant women were used as control. The samples (G-Ⅱ . G-Ⅲ and G-Ⅳ) obtained f...Early pregnancy factor (EPF) was purified from the pooled sera of 21 0 pregnant women at 3- 8 weeks of gestation. Sera from healthy nonpregnant women were used as control. The samples (G-Ⅱ . G-Ⅲ and G-Ⅳ) obtained from pregnant women had EPF activity but no HCG activity. Polyacrylamide gel electrophoresis showed that the major bands in pregnant G-Ⅲ and G-Ⅳ were at similar positions in tube gels. The results of SDS-PAGE showed 3 bands in pregnant G-Ⅳ: 57. 0 kD. 38. 0 kD and 19. 0 kD. The basic active form of EPF may be a small peptide of 1 9. 0 kD. The isoelectric points of pregnant G-Ⅳ were 6. 45 and 8. 20.展开更多
The detection of biomarkers is of great significance in the diagnosis of numerous diseases,especially cancer.Herein,we developed a sensitive and universal fluorescent aptasensor strategy based on magnetic beads,DNA G-...The detection of biomarkers is of great significance in the diagnosis of numerous diseases,especially cancer.Herein,we developed a sensitive and universal fluorescent aptasensor strategy based on magnetic beads,DNA G-quadruplex,and exonuclease Ⅲ(Exo Ⅲ).In the presence of a target protein,a label-free single strand DNA(ssDNA)hybridized with the aptamer was released as a trigger DNA due to specific recognition between the aptamer and target.Subsequently,ssDNA initiates the ExoⅢ-aided recycling to amplify the fluorescence signal,which was caused by N-methylmesoporphyrin IX(NMM)insertion into the G-quadruplex structure.This proposed strategy combines the excellent specificity between the aptamer and target,high sensitivity of the fluorescence signal by G-quadruplex and ExoⅢ-aided recycling amplification.We selected(50-1200 nmol/L)MUC1,a common tumor biomarker,as the proof-of-concept target to test the specificity of our aptasenso r.Results reveal that the sensor sensitively and selectively detected the target protein with limits of detection(LODs)of 3.68 and 12.83 nmol/L in buffer solution and 10%serum system,respectively.The strategy can be easily applied to other targets by simply substituting corresponding aptamers and has great potential in the diagnosis and monitoring of several diseases.展开更多
基金supported by the Natural Science Foundation of Tianjin City of China (No.18JCYBJC17700)
文摘A new,facile,and efficient way to prepare alkalinized g-C3N4 is presented.We calcined a mixture of KCl and melamine to obtain g-C3N4,whose in-plane structure was K+doped so that alkalinized samples could be obtained by treatment with different concentrations of KOH.The different samples were used to oxidize As(Ⅲ)in both visible light and natural light.The sample treated with 10 mol/L KOH showed the highest efficiency,converting all As(Ⅲ)into As(Ⅴ)within 120 min in both visible light and natural light,as the oxidative capacity of the As(Ⅲ)in the alkalinized samples was significantly higher than that of the original samples.K+doping improved the electron transport capacity of the samples,while the alkalinized samples could destroy their edge structures,so as to improve the separation efficiency of the photogenerated carrier.The experiment confirmed that alkalinized g-C3N4 significantly improves the oxidation ability of As(Ⅲ)and plays an important role in the photocatalytic treatment of refractory nonmetallic ions.
文摘Element doping is a simple and effective method to improve photocatalytic activity of g-C3N4. However, the doping model and mechanism of metal elements are still uncharacterized. In this study, we found that Fe(Ⅲ) can be doped into g-C3N4 through the coordination between amidogen and Fe(Ⅲ). After activity tests, it was found that this coordination doping of Fe(Ⅲ) could enhance the Rh B oxidation and Cr(Ⅵ) reduction activities of g-C3N4 in interesting ways, but it is not helpful for the NO-removal performance of g-C3N4. Characterization and calculation results show that the coordination of Fe(Ⅲ) can not only improve the transfer of photogenerated electrons, but it also can passivate the carbon site of triazine rings, which is the active site of NO-removal. This study revealed some doping mechanisms and effect mechanisms of elemental metal in photocatalysis.
文摘Early pregnancy factor (EPF) was purified from the pooled sera of 21 0 pregnant women at 3- 8 weeks of gestation. Sera from healthy nonpregnant women were used as control. The samples (G-Ⅱ . G-Ⅲ and G-Ⅳ) obtained from pregnant women had EPF activity but no HCG activity. Polyacrylamide gel electrophoresis showed that the major bands in pregnant G-Ⅲ and G-Ⅳ were at similar positions in tube gels. The results of SDS-PAGE showed 3 bands in pregnant G-Ⅳ: 57. 0 kD. 38. 0 kD and 19. 0 kD. The basic active form of EPF may be a small peptide of 1 9. 0 kD. The isoelectric points of pregnant G-Ⅳ were 6. 45 and 8. 20.
基金supported by grants from the National Natural Science Foundation of China (No.21472060)Shenzhen Municipal government (Nos.JCYJ20160301153959476 and JCYJ20160324163734374)Shenzhen Reform Commission (Disciplinary Development Program for Chemical Biology)
文摘The detection of biomarkers is of great significance in the diagnosis of numerous diseases,especially cancer.Herein,we developed a sensitive and universal fluorescent aptasensor strategy based on magnetic beads,DNA G-quadruplex,and exonuclease Ⅲ(Exo Ⅲ).In the presence of a target protein,a label-free single strand DNA(ssDNA)hybridized with the aptamer was released as a trigger DNA due to specific recognition between the aptamer and target.Subsequently,ssDNA initiates the ExoⅢ-aided recycling to amplify the fluorescence signal,which was caused by N-methylmesoporphyrin IX(NMM)insertion into the G-quadruplex structure.This proposed strategy combines the excellent specificity between the aptamer and target,high sensitivity of the fluorescence signal by G-quadruplex and ExoⅢ-aided recycling amplification.We selected(50-1200 nmol/L)MUC1,a common tumor biomarker,as the proof-of-concept target to test the specificity of our aptasenso r.Results reveal that the sensor sensitively and selectively detected the target protein with limits of detection(LODs)of 3.68 and 12.83 nmol/L in buffer solution and 10%serum system,respectively.The strategy can be easily applied to other targets by simply substituting corresponding aptamers and has great potential in the diagnosis and monitoring of several diseases.
