A facile approach to the preparation of a novel magnetically separable H_5PMo_（10）V_2O_（40）/Fe_3O_4/g-C_3N_4（PMoV/Fe_3O_4/g-C_3N_4） nanocomposite by chemical impregnation is demonstrated.The prepared nanocomposi...A facile approach to the preparation of a novel magnetically separable H_5PMo_（10）V_2O_（40）/Fe_3O_4/g-C_3N_4（PMoV/Fe_3O_4/g-C_3N_4） nanocomposite by chemical impregnation is demonstrated.The prepared nanocomposite was characterized and its acidity was measured by potentiometric titration.PMoV/Fe_3O_4/g-C_3N_4 showed high catalytic activity in the selective oxidative desulfurization of sulfides to their corresponding sulfoxides or sulfones.The catalytic oxidation of a dibenzothiophene（DBT）-containing model oil and that of real oil were also studied under optimized conditions.In addition,the effects of various nitrogen compounds,as well as the use of one- and two-ring aromatic hydrocarbons as co-solvents,on the catalytic removal of sulfur from DBT were investigated.The catalyst was easily separated and could be recovered from the reaction mixture by using an external magnetic field.Additionally,the remaining reactants could be separated from the products by simple decantation if an appropriate solvent was chosen for the extraction.The advantages of this nanocatalyst are its high catalytic activity and reusability;it can be used at least four times without considerable loss of activity.展开更多
We have extracted and purified flavonoids as active ingredients from Ceylon green tea （Dilmah）. In this project, an in vitro hypoxic model using human brain epithelial cells （HBEC） was studied with treatment of th...We have extracted and purified flavonoids as active ingredients from Ceylon green tea （Dilmah）. In this project, an in vitro hypoxic model using human brain epithelial cells （HBEC） was studied with treatment of the tea extract before inducing hypoxia. We have tested the hypothesis that flavonoids extracted from Ceylon green tea act as potential therapeutic ingredient （s） to reduce oxidative stress in hypoxic cells through its antioxidant properties and its ability to reduce cerebral cellular death. The biochemical antioxidant tests show that the Ceylon green tea has 68% ± 2.8% inhibition property of scavenging of ABTS. The inhibition of pyrogallol red bleaching by HOCI from Ceylon tea was 79% ± 4.5%. After exposing to hypoxia, the cell viability was 29% ± 2.3% in the hypoxia control group but 41% ± 4.7% for flavonoids extract treated group. In LDH assay, flavonoids extract treated group had 75% ± 3.7% reducing of LDH release. The flavonoids extract treated groups significantly increased in antioxidant enzyme activity assays： the activity level of SOD [（1.5 ± 0.6） μmol/min/mg protein], CAT [（0.61 ± 0.06） μmol/min/mg protein], GPx [（2.6 ± 0.41） μmol/min/mg protein] and GST [（6.0 ± 2.4） μmol/min/mg protein] are significantly increased as compared with hypoxic control [（0.5 ± 0.52, 0.51 ± 0.04, 1.2 ± 0.35 and 3.1 ± 1.6） μmol/min/mg protein, respectively]. The study demonstrated a great clinical potential and opened a new avenue to prevent stroke by drinking Ceylon tea.展开更多
Objective: To screen a triple helix-forming oligodeoxyribonucleotide (TFO) that can bind HBV core promoter at target site with high affinity and specificity, and to observe the ability of manganese porphyrin modified ...Objective: To screen a triple helix-forming oligodeoxyribonucleotide (TFO) that can bind HBV core promoter at target site with high affinity and specificity, and to observe the ability of manganese porphyrin modified TFO to combine and cleave HBV DNA. Methods: Similar homopurine domain (1 734 - 1 754) in HBV core promoter was selected as target sequence. Several corresponding TFOs were synthesized. The affinities and specificities of TFOs binding target sequence were tested with electrophoretic mobility shift and DNase I footprinting assays. The selected best TFO was modified with manganese porphyrin and acridine. The ability of the TFO derivative to cleave HBV DNA was observed with cleavage experiment. Results: Under the condition of 371 and pH 7. 4, the TFO consisting of cytidylate and thymidylate (CT-TFO) and the parallel TFO consisting of guanylate and thymidylate (GT-TFOp) bound the target sequence weakly with Kd values much more than 10 -6 mol/L. The affinities of anti-parallel GT-TFO ( GT-TFOap) and short TFO consisting of adenine nucleotide and guanylate (AG-TFOsh) binding the target sequence were higher than those of the formers, with Kd values of 5 μ 10-7 mol/L and 2. 5 μ 10-8 mol/L respectively. Long AG-TFO (AG-TF01) had the highest binding affinity with a Kd value of 3 μ 10 -9 mol/L among all the TFOs studied for sequence specificity. In the presence of potassium monopersulfate, KHSO5, TFO modified with manganese porphyrin and acridine cleaved the target sequence where the triplex DNA formed. Conclusion: TFO containing AG or GT binds homopurine in HBV core promoter in adverse parallel direction to form triple helix. AG-TFO1 has the highest binding affinity among all the TFOs studied. After modified with manganese porphyrin, AG-TFO1 completely binds and cleaves the target HBV DNA sequence where triplex DNA is formed.展开更多
基金the Razi University Research Council for support of this work
文摘A facile approach to the preparation of a novel magnetically separable H_5PMo_（10）V_2O_（40）/Fe_3O_4/g-C_3N_4（PMoV/Fe_3O_4/g-C_3N_4） nanocomposite by chemical impregnation is demonstrated.The prepared nanocomposite was characterized and its acidity was measured by potentiometric titration.PMoV/Fe_3O_4/g-C_3N_4 showed high catalytic activity in the selective oxidative desulfurization of sulfides to their corresponding sulfoxides or sulfones.The catalytic oxidation of a dibenzothiophene（DBT）-containing model oil and that of real oil were also studied under optimized conditions.In addition,the effects of various nitrogen compounds,as well as the use of one- and two-ring aromatic hydrocarbons as co-solvents,on the catalytic removal of sulfur from DBT were investigated.The catalyst was easily separated and could be recovered from the reaction mixture by using an external magnetic field.Additionally,the remaining reactants could be separated from the products by simple decantation if an appropriate solvent was chosen for the extraction.The advantages of this nanocatalyst are its high catalytic activity and reusability;it can be used at least four times without considerable loss of activity.
文摘We have extracted and purified flavonoids as active ingredients from Ceylon green tea （Dilmah）. In this project, an in vitro hypoxic model using human brain epithelial cells （HBEC） was studied with treatment of the tea extract before inducing hypoxia. We have tested the hypothesis that flavonoids extracted from Ceylon green tea act as potential therapeutic ingredient （s） to reduce oxidative stress in hypoxic cells through its antioxidant properties and its ability to reduce cerebral cellular death. The biochemical antioxidant tests show that the Ceylon green tea has 68% ± 2.8% inhibition property of scavenging of ABTS. The inhibition of pyrogallol red bleaching by HOCI from Ceylon tea was 79% ± 4.5%. After exposing to hypoxia, the cell viability was 29% ± 2.3% in the hypoxia control group but 41% ± 4.7% for flavonoids extract treated group. In LDH assay, flavonoids extract treated group had 75% ± 3.7% reducing of LDH release. The flavonoids extract treated groups significantly increased in antioxidant enzyme activity assays： the activity level of SOD [（1.5 ± 0.6） μmol/min/mg protein], CAT [（0.61 ± 0.06） μmol/min/mg protein], GPx [（2.6 ± 0.41） μmol/min/mg protein] and GST [（6.0 ± 2.4） μmol/min/mg protein] are significantly increased as compared with hypoxic control [（0.5 ± 0.52, 0.51 ± 0.04, 1.2 ± 0.35 and 3.1 ± 1.6） μmol/min/mg protein, respectively]. The study demonstrated a great clinical potential and opened a new avenue to prevent stroke by drinking Ceylon tea.
文摘Objective: To screen a triple helix-forming oligodeoxyribonucleotide (TFO) that can bind HBV core promoter at target site with high affinity and specificity, and to observe the ability of manganese porphyrin modified TFO to combine and cleave HBV DNA. Methods: Similar homopurine domain (1 734 - 1 754) in HBV core promoter was selected as target sequence. Several corresponding TFOs were synthesized. The affinities and specificities of TFOs binding target sequence were tested with electrophoretic mobility shift and DNase I footprinting assays. The selected best TFO was modified with manganese porphyrin and acridine. The ability of the TFO derivative to cleave HBV DNA was observed with cleavage experiment. Results: Under the condition of 371 and pH 7. 4, the TFO consisting of cytidylate and thymidylate (CT-TFO) and the parallel TFO consisting of guanylate and thymidylate (GT-TFOp) bound the target sequence weakly with Kd values much more than 10 -6 mol/L. The affinities of anti-parallel GT-TFO ( GT-TFOap) and short TFO consisting of adenine nucleotide and guanylate (AG-TFOsh) binding the target sequence were higher than those of the formers, with Kd values of 5 μ 10-7 mol/L and 2. 5 μ 10-8 mol/L respectively. Long AG-TFO (AG-TF01) had the highest binding affinity with a Kd value of 3 μ 10 -9 mol/L among all the TFOs studied for sequence specificity. In the presence of potassium monopersulfate, KHSO5, TFO modified with manganese porphyrin and acridine cleaved the target sequence where the triplex DNA formed. Conclusion: TFO containing AG or GT binds homopurine in HBV core promoter in adverse parallel direction to form triple helix. AG-TFO1 has the highest binding affinity among all the TFOs studied. After modified with manganese porphyrin, AG-TFO1 completely binds and cleaves the target HBV DNA sequence where triplex DNA is formed.
