Rho kinase （ROCK） was the first downstream Rho effector found to mediate RhoA-induced actin cytoskeletal changes through effects on myosin light chain phosphorylation. There is abundant evidence that the ROCK pathwa...Rho kinase （ROCK） was the first downstream Rho effector found to mediate RhoA-induced actin cytoskeletal changes through effects on myosin light chain phosphorylation. There is abundant evidence that the ROCK pathway participates in the pathogenesis of retinal endothelial injury and proliferative epiretinal membrane traction. In this study, we investigated the effect of the ROCK pathway inhibitor Y-27632 on retinal Müller cells subjected to hypoxia or oxidative stress. Müller cells were subjected to hypoxia or oxidative stress by exposure to CoCl2 or H2O2. After a 24-hour treatment with Y-27632, the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide assay was used to assess the survival of Müller cells. Hoechst 33258 was used to detect apoptosis, while 2′,7′-dichlorodihydrofluorescein diacetate was used to measure reactive oxygen species generation. A transwell chamber system was used to examine the migration ability of Müller cells. Western blot assay was used to detect the expression levels of α-smooth muscle actin, glutamine synthetase and vimentin. After treatment with Y-27632, Müller cells subjected to hypoxia or oxidative stress exhibited a morphology similar to control cells. Y-27632 reduced apoptosis, α-smooth muscle actin expression and reactive oxygen species generation under oxidative stress, and it reduced cell migration under hypoxia. Y-27632 also upregulated glutamine synthetase expression under hypoxia but did not impact vimentin expression. These findings suggest that Y-27632 protects Müller cells against cellular injury caused by oxidative stress and hypoxia by inhibiting the ROCK pathway.展开更多
Liver diseases with the central pathogenetic mechanism of oxidative stress are one of the main causes of mortality worldwide.Therefore,dihydroquinoline derivatives,which are precursors of hepatoprotectors and have ant...Liver diseases with the central pathogenetic mechanism of oxidative stress are one of the main causes of mortality worldwide.Therefore,dihydroquinoline derivatives,which are precursors of hepatoprotectors and have antioxidant activity,are of interest.We have previously found that some compounds in this class have the ability to normalize redox homeostasis under experimental conditions.Here,we initially analyzed the hepatoprotective potential of the dihydroquinoline derivative 1-benzoyl-6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline(BHDQ)for carbon tetrachloride(CCl4)-induced liver injury in rats.Results suggested that BHDQ normalized the alanine aminotransferase,aspartate aminotransferase,and gamma-glutamyl transpeptidase in serum.We also observed an improvement in liver tissue morphology related to BHDQ.Animals with CCl4-induced liver injuries treated with BHDQ had less oxidative stress compared to animals with CCl4-induced liver injury.BHDQ promoted activation changes in superoxide dismutase,catalase,glutathione peroxidase,glutathione reductase,and glutathione transferase on control values in animals with CCl4-induced liver injury.BHDQ also activated gene transcription in Sod1 and Gpx1 via nuclear factor erythroid 2-related factor 2 and forkhead box protein O1 factors.Therefore,the compound of concern has a hepatoprotective effect by inhibiting the development of necrotic processes in the liver tissue,through antioxidation.展开更多
The aim of this study was to investigate the possible protective effects and mechanisms of 20-hydroxyecdysone, an insect steroid hormone, on HEO2-induced cytotoxicity in human neuroblastoma SH-SYSY cells. Pretreatment...The aim of this study was to investigate the possible protective effects and mechanisms of 20-hydroxyecdysone, an insect steroid hormone, on HEO2-induced cytotoxicity in human neuroblastoma SH-SYSY cells. Pretreatment with 20-hydroxyecdysone significantly elevated the cell viability and decreased LDH leakage in H2O2-treated SH-SY5Y cells. 20-Hydroxyecdysone also dramatically reduced malondialdehyde （MDA） contents and enhanced the superoxide dismutase （SOD） activities under oxidative stress conditions. Furthermore, 20-hydroxyecdysone pretreatment inhibited apoptosis by decreasing the Bax/Bcl-2 ratio and attenuating the activation of caspase-3. These results suggest that 20-hydroxyecdysone can protect SH-SYSY cells against H2O2-induced cytotoxicity and might potentially be used to treat neurodegenerative diseases induced by oxidative stress and anontosis.展开更多
Eucommia ulmoides Oliv.(EuO),also known as Duzhong,native to China,has been reported to have antioxidative function,but its cellular mechanism is not fully examined yet.We investigated inhibitory effects of EuO leaf e...Eucommia ulmoides Oliv.(EuO),also known as Duzhong,native to China,has been reported to have antioxidative function,but its cellular mechanism is not fully examined yet.We investigated inhibitory effects of EuO leaf ethanol extracts on H2O2-induced apoptosis in rat osteoblastic MC3T3-E1 cells and underlying mechanisms.Locally-grown Duzhong leaves were extracted with ethanol.MC3T3-E1 cells were treated with EuO (6.25,12.5,25,50,and 100 μg/ml) for 24 h,and then H2O2 (800 μmol/L) for an additional 24 h.Cell survival rate,percentage of apoptosis,and expressions of caspases 3,6,7,and 9 were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay,microscopic analysis,Western blotting,and reverse transcription polymerase chain reaction (RT-PCR).The final EuO leaf ethanol extract powder was detected to contain caffeotannic acid at 58 mg/g and geniposide at 3.45 mg/g by high performance liquid chromatography (HPLC).EuO remarkably restrained cell oxidative damage and increased cell survival rate in a dose-dependent manner: 0 μg/ml,0.21;6.25 μg/ml,0.28;12.5 μg/ml,0.31;25 μg/ml,0.48;50 μg/ml,0.54;and 100 μg/ml,0.66 (P<0.05),with the half-effective concentration being around 25 μg/ml.MTT results were confirmed by microscopic analysis.Western blotting and RT-PCR analyses showed that the expressions of caspases 3,6,7,and 9 were significantly decreased in the EuO-treated cells compared with the control (EuOand H2O2-free) (P<0.05),with the half-effective concentration of EuO ranging from 12.5 to 25 μg/ml.We conclude that the ethanol-extracted EuO leaf extracts promoted the growth of MC3T3-E1 cells,and suppressed the H2O2-induced apoptosis in a rat MC3T3-E1 osteogenic cell model,likely due to the inhibition of caspases’ activities.The results indicate that EuO is a potent antioxidant,which may contribute to its many cellular protective functions,including the promotion of bone growth.展开更多
An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals.Various substituted toluenes（NO2,Cl,Br,H,CH3） were high selectively ...An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals.Various substituted toluenes（NO2,Cl,Br,H,CH3） were high selectively brominated at the benzyl position for monobromination in CH2C12 at ice water with catalyst free.This simple but effective bromination of toluene derivatives with an aqueous H2O2-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.展开更多
A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observe...A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.展开更多
Large amounts of cyanide tailings are produced during the cyanidation process in gold extraction,which are hazardous solid wastes due to the toxic cyanide.Pyrite is one of the main minerals in cyanide tailings.The rem...Large amounts of cyanide tailings are produced during the cyanidation process in gold extraction,which are hazardous solid wastes due to the toxic cyanide.Pyrite is one of the main minerals in cyanide tailings.The removal of cyanide adsorbed on pyrite by H_2O_2 oxidation under alkaline conditions was investigated in this study.It was found that the removal efficiency was positively correlated with pH from 5 to 12,but remained almost constant when pH was higher than 12.The highest cyanide removal efficiency of 91.10% was achieved by adding no less than 0.6 wt.% of H_2O_2.Cyanide removal was positively correlated with the CN^-adsorption amount between 1.06 and 8.5 mg/g,and temperature between 25 and 85°C.The removal of cyanide adsorbed on pyrite by H_2O_2 oxidation under alkaline conditions was due to the oxidation of pyrite.Hexacyanoferrate,thiocyanate and sulfate were generated with mole ratios of about 2.03:1.12:3.17 during the cyanide removal.?2018 The Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences.展开更多
Mn-Ni oxides with different compositions were prepared using standard co-precipitation(CP) and urea hydrolysis-precipitation(UH) methods and optimized for the selective catalytic reduction of nitrogen oxides(NOx) by N...Mn-Ni oxides with different compositions were prepared using standard co-precipitation(CP) and urea hydrolysis-precipitation(UH) methods and optimized for the selective catalytic reduction of nitrogen oxides(NOx) by NH3 at low temperature.Mn((2))Ni(1)Ox-CP and Mn(2)Ni(1)Ox-UH(with Mn:Ni molar ratio of 2:1) catalysts showed almost identical selective catalytic reduction(SCR) catalytic activity,with about 96% NOx conversion at 750 C and-99%in the temperature range from 100 to 250℃.X-ray diffraction(XRD) results showed that Mn(2)Ni(1)Ox-CP and Mn(2)Ni(1)Ox-UH catalysts crystallized in the form of Mn2NiO4 and MnO2-Mn2NiO4 spinel,respectively.The latter gave relatively good selectivity to N2,which might be due to the presence of the MnO2 phase and high metal-O binding energy,resulting in low dehydrogenation ability.According to the results of various characterization methods,it was found that a high density of surface chemisorbed oxygen species and efficient electron transfer between Mn and Ni in the crystal structure of Mn2NiO4 spinel played important roles in the high-efficiency SCR activity of these catalysts.Mn(2)Ni(1)Ox catalysts presented good resistance to H2O or/and SO2 with stable activity,which benefited from the Mn2NiO4 spinel structure and Eley-Rideal mechanism,with only slight effects from SO2.展开更多
The oxidation kinetics,surface morphology and phase structure of oxide films grown on 25Cr20Ni alloy in air-H2O and H2-H2O atmospheres at 900 ℃ for 20 h were investigated.The anti-coking performance and resistance to...The oxidation kinetics,surface morphology and phase structure of oxide films grown on 25Cr20Ni alloy in air-H2O and H2-H2O atmospheres at 900 ℃ for 20 h were investigated.The anti-coking performance and resistance to carburization of the two oxide films were compared using 25Cr20Ni alloy tubes with an inner diameter of 10 mm and a length of 850 mm in a bench scale naphtha steam pyrolysis unit.The oxidation kinetics followed a parabolic law in an air-H2O atmosphere and a logarithm law in a H2-H2O atmosphere in the steady-state stage.The oxide film grown in the air-H2O atmosphere had cracks where the elements Fe and Ni were enriched and the un-cracked area was covered with octahedral-shaped MnCr2O4 spinels and Cr1.3Fe0.7O3 oxide clusters,while the oxide film grown in the H2-H2O atmosphere was intact and completely covered with dense standing blade MnCr2O4 spinels.In the pyrolysis tests,the anti-coking performance and resistance to carburization of the oxide film grown in the H2-H2O atmosphere were far better than that in the air-H2O atmosphere.The mass of coke formed in the oxide film grown in the H2-H2O atmosphere was less than 10％ of that in the air-H2O atmosphere.The Cr1.3Fe0.7O3 oxide clusters converted into Cr23C6 carbides and the cracks were filled with carbon in the oxide film grown in the air-H2O atmosphere after repeated coking and decoking tests,while the dense standing blade MnCr2O4 spinels remained unchanged in the oxide film grown in the H2-H2O atmosphere.The ethylene,propylene and butadiene yields in the pyrolysis tests were almost the same for the two oxide films.展开更多
The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modifi...The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modification of H3PW12O40（40%）/SiO2 gave the most promising result of 20% dimethyl ether conversion and 34.8% dimethoxymethane selectivity. Dimethoxymethane could be synthe- sized via methoxy groups decomposed from dimethyl ether through the synergistic effect between the acid sites and the redox sites of Cs modified H3PW12O40（40%）/SiO2.展开更多
DBUH-Br_3 catalyzed selective conversion of sulfides to sulfoxides in the presence of H_2O_2 as oxidizing agent is described.The reaction was performed selectively at room temperature and relatively short reaction times.
Vapor phase catalytic hydrogen peroxide production by oxidation of water is possible by coupling the reaction with oxidation of an organic sacrificial reductant. It is potentially a safer process than direct synthesis...Vapor phase catalytic hydrogen peroxide production by oxidation of water is possible by coupling the reaction with oxidation of an organic sacrificial reductant. It is potentially a safer process than direct synthesis from H2 and O2. Based on mechanistic information available mostly for liquid phase catalytic processes, feasible reaction mechanisms for such coupled reactions are proposed based on which desirable catalyst properties are identified. It is found that the surface-adsorbed oxygen bond is an important parameter for identifying desirable catalysts. Thermodynamics can be used to identify the types of organic oxidation reactions that can couple with water oxidation such that H2O2 formation becomes thermodynamically favorable. Reactions such as epoxidation of alkenes and selective oxidation of alkanes to alcohols cannot provide sufficient thermodynamic driving force, whereas oxidation of alcohols to aldehydes and to acids can. Finally, further research is suggested to identify catalytic properties important for H2O2 decomposition and for coupling selective oxidation of organic compounds to oxidation of H2O in order to facilitate development of H2O2 production coupled with selective organic oxidation.展开更多
Direct propylene epoxidation with H2 and O2,an attractive process to produce propylene oxide(PO),has a potential explosion danger due to the coexistence of flammable gases(i.e.,C3 H6 and H2)and oxidizer(i.e.,O2).The u...Direct propylene epoxidation with H2 and O2,an attractive process to produce propylene oxide(PO),has a potential explosion danger due to the coexistence of flammable gases(i.e.,C3 H6 and H2)and oxidizer(i.e.,O2).The unknown explosion limits of the multi-component feed gas mixture make it difficult to optimize the reaction process under safe operation conditions.In this work,a distribution method is proposed and verified to be effective by comparing estimated and experimental explosion limits of more than 200 kinds of flammable gas mixture.Then,it is employed to estimate the explosion limits of the feed gas mixture,some results of which are also validated by the classic Le Chatelier’s Rule and flammable resistance method.Based on the estimated explosion limits,process optimization is carried out using commercially high and inherently safe reactant concentrations to enhance reaction performance.The promising results are directly obtained through the interface called gOPT in gPROMS only by using a simple,easy-constructed and mature packed-bed reactor,such as the PO yield of 13.3%,PO selectivity of 85.1%and outlet PO fraction of 1.8%.These results can be rationalized by indepth analyses and discussion about the effects of the decision variables on the operation safety and reaction performance.The insights revealed here could shed new light on the process development of the PO production based on the estimation of the explosion limits of the multi-component feed gas mixture containing flammable gase s,inert gas and O2,followed by process optimization.展开更多
The degradations of hexazinone and aldicarb by direct ozonation combined an advanced oxidation process( AOP) of O3/H2O2 were investigated in this study focusing on the oxidation mechanism by identifying the hydrogen p...The degradations of hexazinone and aldicarb by direct ozonation combined an advanced oxidation process( AOP) of O3/H2O2 were investigated in this study focusing on the oxidation mechanism by identifying the hydrogen peroxide consumption during the oxidation process of the two chemicals. The results showed that H2O2 could enhance the removal rate of the triazine herbicide hexazinone,and it was consumed along with the variation of removal rate in the light of different pH levels. The addition of H2O2 contributed little to the removal of the thiocarbamate herbicide aldicarb and H2O2 content kept constantly throughout the degradation process. Tert-butyl alcohol( TBA) effectively scavenged the ·OH radical for hexazinone,but had no effect on the removal rate of aldicarb. Aldicarb removal was mainly attributed to direct ozonation molecule in both O3( 97.00%) and O3/H2O2( 96.76%)systems. Moreover,sole O3 could hardly oxidize hexazinone whereas·OH radicals contribute respective 74.70% and 97.50% of removal in O3 system and O3/H2O2 AOP. All of these findings suggest that the mechanism of ·OH radical generation and the chain reaction in O3/H2O2 AOP should be further discussed.展开更多
Tongting coal(TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone(CS 2 /NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmissi...Tongting coal(TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone(CS 2 /NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmission electron microscope(TEM) and Fourier transform infrared(FTIR) spectrometer.The results show that the nanometer particles of extract,which were free of ash,are superfine and superclean with tract content of 0.02% A d and particles size of about 100-150 nm.TTC and extract were then subject to oxidation with H 2 O 2 and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer(GC/MS).The results show that extract is more reactive with H 2 O 2 in comparison to TTC and richer in oxygen-containing species including phenols,alcohols,ethers,esters,carboxylic acids and anhydrides.展开更多
V（HSO4）3 has been found to be an efficient reagent for the promotion of the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds with Cu（NO3...V（HSO4）3 has been found to be an efficient reagent for the promotion of the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds with Cu（NO3）2-3H2O in the absence of solvent.展开更多
Nitric oxide(NO) from flue gas is hard to remove because of low solubility and reactivity. A new technology for photocatalytic oxidation of NO using ultraviolet(UV)/TiO2/H2O2 process is studied in an efficient laborat...Nitric oxide(NO) from flue gas is hard to remove because of low solubility and reactivity. A new technology for photocatalytic oxidation of NO using ultraviolet(UV)/TiO2/H2O2 process is studied in an efficient laboratory-scale reactor. Effects of several key operational parameters on NO removal efficiency are studied, including TiO2 content, H2O2 initial concentration, UV lamp power, NO initial content, oxygen volume fraction and TiO2/H2O2 solution volume. The results illustrate that the NO removal efficiency increases with the increasing of H2O2 initial concentration or UV lamp power. Meanwhile, a lower NO initial content or a higher TiO2/H2O2 solution volume will result in higher NO removal efficiency. In addition, oxygen volume fraction has a little effect.The highest NO removal efficiency is achieved at the TiO2 content of 0.75 g/L, H2O2 initial concentration of 2.5 mol/L, UV lamp power of 36 W, NO initial content of 206×10-6 and TiO2/H2O2 solution volume of 600 m L. It is beneficial for the development and application of NO removal from coal-fired flue gas with UV/TiO2/H2O2 process.展开更多
The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented ...The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H 2O 2/UV has beneficial effect on mineralization than O 3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.展开更多
基金financially supported by the Scientific and Technological Project of Shaanxi Province of China,No.2016SF-010
文摘Rho kinase （ROCK） was the first downstream Rho effector found to mediate RhoA-induced actin cytoskeletal changes through effects on myosin light chain phosphorylation. There is abundant evidence that the ROCK pathway participates in the pathogenesis of retinal endothelial injury and proliferative epiretinal membrane traction. In this study, we investigated the effect of the ROCK pathway inhibitor Y-27632 on retinal Müller cells subjected to hypoxia or oxidative stress. Müller cells were subjected to hypoxia or oxidative stress by exposure to CoCl2 or H2O2. After a 24-hour treatment with Y-27632, the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide assay was used to assess the survival of Müller cells. Hoechst 33258 was used to detect apoptosis, while 2′,7′-dichlorodihydrofluorescein diacetate was used to measure reactive oxygen species generation. A transwell chamber system was used to examine the migration ability of Müller cells. Western blot assay was used to detect the expression levels of α-smooth muscle actin, glutamine synthetase and vimentin. After treatment with Y-27632, Müller cells subjected to hypoxia or oxidative stress exhibited a morphology similar to control cells. Y-27632 reduced apoptosis, α-smooth muscle actin expression and reactive oxygen species generation under oxidative stress, and it reduced cell migration under hypoxia. Y-27632 also upregulated glutamine synthetase expression under hypoxia but did not impact vimentin expression. These findings suggest that Y-27632 protects Müller cells against cellular injury caused by oxidative stress and hypoxia by inhibiting the ROCK pathway.
基金supported by the Russian Foundation for Basic Research (Grant No. 20-04-00526А)
文摘Liver diseases with the central pathogenetic mechanism of oxidative stress are one of the main causes of mortality worldwide.Therefore,dihydroquinoline derivatives,which are precursors of hepatoprotectors and have antioxidant activity,are of interest.We have previously found that some compounds in this class have the ability to normalize redox homeostasis under experimental conditions.Here,we initially analyzed the hepatoprotective potential of the dihydroquinoline derivative 1-benzoyl-6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline(BHDQ)for carbon tetrachloride(CCl4)-induced liver injury in rats.Results suggested that BHDQ normalized the alanine aminotransferase,aspartate aminotransferase,and gamma-glutamyl transpeptidase in serum.We also observed an improvement in liver tissue morphology related to BHDQ.Animals with CCl4-induced liver injuries treated with BHDQ had less oxidative stress compared to animals with CCl4-induced liver injury.BHDQ promoted activation changes in superoxide dismutase,catalase,glutathione peroxidase,glutathione reductase,and glutathione transferase on control values in animals with CCl4-induced liver injury.BHDQ also activated gene transcription in Sod1 and Gpx1 via nuclear factor erythroid 2-related factor 2 and forkhead box protein O1 factors.Therefore,the compound of concern has a hepatoprotective effect by inhibiting the development of necrotic processes in the liver tissue,through antioxidation.
文摘The aim of this study was to investigate the possible protective effects and mechanisms of 20-hydroxyecdysone, an insect steroid hormone, on HEO2-induced cytotoxicity in human neuroblastoma SH-SYSY cells. Pretreatment with 20-hydroxyecdysone significantly elevated the cell viability and decreased LDH leakage in H2O2-treated SH-SY5Y cells. 20-Hydroxyecdysone also dramatically reduced malondialdehyde （MDA） contents and enhanced the superoxide dismutase （SOD） activities under oxidative stress conditions. Furthermore, 20-hydroxyecdysone pretreatment inhibited apoptosis by decreasing the Bax/Bcl-2 ratio and attenuating the activation of caspase-3. These results suggest that 20-hydroxyecdysone can protect SH-SYSY cells against H2O2-induced cytotoxicity and might potentially be used to treat neurodegenerative diseases induced by oxidative stress and anontosis.
基金Project (No.2007C33030) supported by the Science and Technology Program of Zhejiang Province,China
文摘Eucommia ulmoides Oliv.(EuO),also known as Duzhong,native to China,has been reported to have antioxidative function,but its cellular mechanism is not fully examined yet.We investigated inhibitory effects of EuO leaf ethanol extracts on H2O2-induced apoptosis in rat osteoblastic MC3T3-E1 cells and underlying mechanisms.Locally-grown Duzhong leaves were extracted with ethanol.MC3T3-E1 cells were treated with EuO (6.25,12.5,25,50,and 100 μg/ml) for 24 h,and then H2O2 (800 μmol/L) for an additional 24 h.Cell survival rate,percentage of apoptosis,and expressions of caspases 3,6,7,and 9 were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay,microscopic analysis,Western blotting,and reverse transcription polymerase chain reaction (RT-PCR).The final EuO leaf ethanol extract powder was detected to contain caffeotannic acid at 58 mg/g and geniposide at 3.45 mg/g by high performance liquid chromatography (HPLC).EuO remarkably restrained cell oxidative damage and increased cell survival rate in a dose-dependent manner: 0 μg/ml,0.21;6.25 μg/ml,0.28;12.5 μg/ml,0.31;25 μg/ml,0.48;50 μg/ml,0.54;and 100 μg/ml,0.66 (P<0.05),with the half-effective concentration being around 25 μg/ml.MTT results were confirmed by microscopic analysis.Western blotting and RT-PCR analyses showed that the expressions of caspases 3,6,7,and 9 were significantly decreased in the EuO-treated cells compared with the control (EuOand H2O2-free) (P<0.05),with the half-effective concentration of EuO ranging from 12.5 to 25 μg/ml.We conclude that the ethanol-extracted EuO leaf extracts promoted the growth of MC3T3-E1 cells,and suppressed the H2O2-induced apoptosis in a rat MC3T3-E1 osteogenic cell model,likely due to the inhibition of caspases’ activities.The results indicate that EuO is a potent antioxidant,which may contribute to its many cellular protective functions,including the promotion of bone growth.
基金This project was supported by the National Natural Science Foundation of Zhejiang Province(No.Y407306)the National Natural Science Foundation of China(No.20876148)
文摘An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals.Various substituted toluenes（NO2,Cl,Br,H,CH3） were high selectively brominated at the benzyl position for monobromination in CH2C12 at ice water with catalyst free.This simple but effective bromination of toluene derivatives with an aqueous H2O2-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.
基金Funded by the National Natural Science Foundation of China(No.21476177)。
文摘A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.
基金supported by the National Key Research and Development Program of China (No. 2017YFC0703200)
文摘Large amounts of cyanide tailings are produced during the cyanidation process in gold extraction,which are hazardous solid wastes due to the toxic cyanide.Pyrite is one of the main minerals in cyanide tailings.The removal of cyanide adsorbed on pyrite by H_2O_2 oxidation under alkaline conditions was investigated in this study.It was found that the removal efficiency was positively correlated with pH from 5 to 12,but remained almost constant when pH was higher than 12.The highest cyanide removal efficiency of 91.10% was achieved by adding no less than 0.6 wt.% of H_2O_2.Cyanide removal was positively correlated with the CN^-adsorption amount between 1.06 and 8.5 mg/g,and temperature between 25 and 85°C.The removal of cyanide adsorbed on pyrite by H_2O_2 oxidation under alkaline conditions was due to the oxidation of pyrite.Hexacyanoferrate,thiocyanate and sulfate were generated with mole ratios of about 2.03:1.12:3.17 during the cyanide removal.?2018 The Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences.
基金financially supported by the National Key R&D Program of China (No.2017YFC0210303)National Natural Science Foundation of China (Nos.21806009 and 21677010)+1 种基金China Postdoctoral Science Foundation (Nos.2019T120049 and 2018M631344)Fundamental Research Funds for the Central Universities (No.FRF-TP-18-019A1).
文摘Mn-Ni oxides with different compositions were prepared using standard co-precipitation(CP) and urea hydrolysis-precipitation(UH) methods and optimized for the selective catalytic reduction of nitrogen oxides(NOx) by NH3 at low temperature.Mn((2))Ni(1)Ox-CP and Mn(2)Ni(1)Ox-UH(with Mn:Ni molar ratio of 2:1) catalysts showed almost identical selective catalytic reduction(SCR) catalytic activity,with about 96% NOx conversion at 750 C and-99%in the temperature range from 100 to 250℃.X-ray diffraction(XRD) results showed that Mn(2)Ni(1)Ox-CP and Mn(2)Ni(1)Ox-UH catalysts crystallized in the form of Mn2NiO4 and MnO2-Mn2NiO4 spinel,respectively.The latter gave relatively good selectivity to N2,which might be due to the presence of the MnO2 phase and high metal-O binding energy,resulting in low dehydrogenation ability.According to the results of various characterization methods,it was found that a high density of surface chemisorbed oxygen species and efficient electron transfer between Mn and Ni in the crystal structure of Mn2NiO4 spinel played important roles in the high-efficiency SCR activity of these catalysts.Mn(2)Ni(1)Ox catalysts presented good resistance to H2O or/and SO2 with stable activity,which benefited from the Mn2NiO4 spinel structure and Eley-Rideal mechanism,with only slight effects from SO2.
基金financially supported by the scientific research project of China Petroleum and Chemical Corporation(No.409075)
文摘The oxidation kinetics,surface morphology and phase structure of oxide films grown on 25Cr20Ni alloy in air-H2O and H2-H2O atmospheres at 900 ℃ for 20 h were investigated.The anti-coking performance and resistance to carburization of the two oxide films were compared using 25Cr20Ni alloy tubes with an inner diameter of 10 mm and a length of 850 mm in a bench scale naphtha steam pyrolysis unit.The oxidation kinetics followed a parabolic law in an air-H2O atmosphere and a logarithm law in a H2-H2O atmosphere in the steady-state stage.The oxide film grown in the air-H2O atmosphere had cracks where the elements Fe and Ni were enriched and the un-cracked area was covered with octahedral-shaped MnCr2O4 spinels and Cr1.3Fe0.7O3 oxide clusters,while the oxide film grown in the H2-H2O atmosphere was intact and completely covered with dense standing blade MnCr2O4 spinels.In the pyrolysis tests,the anti-coking performance and resistance to carburization of the oxide film grown in the H2-H2O atmosphere were far better than that in the air-H2O atmosphere.The mass of coke formed in the oxide film grown in the H2-H2O atmosphere was less than 10％ of that in the air-H2O atmosphere.The Cr1.3Fe0.7O3 oxide clusters converted into Cr23C6 carbides and the cracks were filled with carbon in the oxide film grown in the air-H2O atmosphere after repeated coking and decoking tests,while the dense standing blade MnCr2O4 spinels remained unchanged in the oxide film grown in the H2-H2O atmosphere.The ethylene,propylene and butadiene yields in the pyrolysis tests were almost the same for the two oxide films.
基金Foundation items:the National Natural Science Foundation of China(No.20373085)the Natural Science Foundation of Shanxi Province(No.20051023)
文摘The attractive utilization route for one-step catalytic oxidation of dimethyl ether to dimethoxymethane was successfully carried out over the H3PW12O40（40%）/SiO2 catalyst, modified by Cs, K, Ni, and V. The Cs modification of H3PW12O40（40%）/SiO2 gave the most promising result of 20% dimethyl ether conversion and 34.8% dimethoxymethane selectivity. Dimethoxymethane could be synthe- sized via methoxy groups decomposed from dimethyl ether through the synergistic effect between the acid sites and the redox sites of Cs modified H3PW12O40（40%）/SiO2.
文摘DBUH-Br_3 catalyzed selective conversion of sulfides to sulfoxides in the presence of H_2O_2 as oxidizing agent is described.The reaction was performed selectively at room temperature and relatively short reaction times.
基金support by Northwestern University through a gift from Dr.Warren Haug is greatly appreciated
文摘Vapor phase catalytic hydrogen peroxide production by oxidation of water is possible by coupling the reaction with oxidation of an organic sacrificial reductant. It is potentially a safer process than direct synthesis from H2 and O2. Based on mechanistic information available mostly for liquid phase catalytic processes, feasible reaction mechanisms for such coupled reactions are proposed based on which desirable catalyst properties are identified. It is found that the surface-adsorbed oxygen bond is an important parameter for identifying desirable catalysts. Thermodynamics can be used to identify the types of organic oxidation reactions that can couple with water oxidation such that H2O2 formation becomes thermodynamically favorable. Reactions such as epoxidation of alkenes and selective oxidation of alkanes to alcohols cannot provide sufficient thermodynamic driving force, whereas oxidation of alcohols to aldehydes and to acids can. Finally, further research is suggested to identify catalytic properties important for H2O2 decomposition and for coupling selective oxidation of organic compounds to oxidation of H2O in order to facilitate development of H2O2 production coupled with selective organic oxidation.
基金Supported by the National Natural Science Foundation of China(91434117,21776077)the Shanghai Rising-Star Program(17QA1401200)+1 种基金the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learningthe Open Project of State Key Laboratory of Chemical Engineering(SKL-Che-15C03).
文摘Direct propylene epoxidation with H2 and O2,an attractive process to produce propylene oxide(PO),has a potential explosion danger due to the coexistence of flammable gases(i.e.,C3 H6 and H2)and oxidizer(i.e.,O2).The unknown explosion limits of the multi-component feed gas mixture make it difficult to optimize the reaction process under safe operation conditions.In this work,a distribution method is proposed and verified to be effective by comparing estimated and experimental explosion limits of more than 200 kinds of flammable gas mixture.Then,it is employed to estimate the explosion limits of the feed gas mixture,some results of which are also validated by the classic Le Chatelier’s Rule and flammable resistance method.Based on the estimated explosion limits,process optimization is carried out using commercially high and inherently safe reactant concentrations to enhance reaction performance.The promising results are directly obtained through the interface called gOPT in gPROMS only by using a simple,easy-constructed and mature packed-bed reactor,such as the PO yield of 13.3%,PO selectivity of 85.1%and outlet PO fraction of 1.8%.These results can be rationalized by indepth analyses and discussion about the effects of the decision variables on the operation safety and reaction performance.The insights revealed here could shed new light on the process development of the PO production based on the estimation of the explosion limits of the multi-component feed gas mixture containing flammable gase s,inert gas and O2,followed by process optimization.
基金Science and Technology Project of Shenzhen,China(No.JCYJ20120617141700417)Natural Science Foundation of Guangdong Province,China(No.2012040007855)
文摘The degradations of hexazinone and aldicarb by direct ozonation combined an advanced oxidation process( AOP) of O3/H2O2 were investigated in this study focusing on the oxidation mechanism by identifying the hydrogen peroxide consumption during the oxidation process of the two chemicals. The results showed that H2O2 could enhance the removal rate of the triazine herbicide hexazinone,and it was consumed along with the variation of removal rate in the light of different pH levels. The addition of H2O2 contributed little to the removal of the thiocarbamate herbicide aldicarb and H2O2 content kept constantly throughout the degradation process. Tert-butyl alcohol( TBA) effectively scavenged the ·OH radical for hexazinone,but had no effect on the removal rate of aldicarb. Aldicarb removal was mainly attributed to direct ozonation molecule in both O3( 97.00%) and O3/H2O2( 96.76%)systems. Moreover,sole O3 could hardly oxidize hexazinone whereas·OH radicals contribute respective 74.70% and 97.50% of removal in O3 system and O3/H2O2 AOP. All of these findings suggest that the mechanism of ·OH radical generation and the chain reaction in O3/H2O2 AOP should be further discussed.
基金subsidized by the National Natural Science Foundation of China (Nos.50474066,50874108 and 50921002)the Fundamental Research Funds for the Central Universities(No.2010LKHX01)the National Basic Research Program of China (No.2012CB214900)
文摘Tongting coal(TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone(CS 2 /NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmission electron microscope(TEM) and Fourier transform infrared(FTIR) spectrometer.The results show that the nanometer particles of extract,which were free of ash,are superfine and superclean with tract content of 0.02% A d and particles size of about 100-150 nm.TTC and extract were then subject to oxidation with H 2 O 2 and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer(GC/MS).The results show that extract is more reactive with H 2 O 2 in comparison to TTC and richer in oxygen-containing species including phenols,alcohols,ethers,esters,carboxylic acids and anhydrides.
基金the University of Guilan Research Council for the partial support of this work
文摘V（HSO4）3 has been found to be an efficient reagent for the promotion of the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds with Cu（NO3）2-3H2O in the absence of solvent.
基金Project(2011CB201505)supported by the National Key Basic Research Program of ChinaProject(BA2011031)supported by the Special Fund of Transformation of Scientific and Technological Achievements of Jiangsu Province,China
文摘Nitric oxide(NO) from flue gas is hard to remove because of low solubility and reactivity. A new technology for photocatalytic oxidation of NO using ultraviolet(UV)/TiO2/H2O2 process is studied in an efficient laboratory-scale reactor. Effects of several key operational parameters on NO removal efficiency are studied, including TiO2 content, H2O2 initial concentration, UV lamp power, NO initial content, oxygen volume fraction and TiO2/H2O2 solution volume. The results illustrate that the NO removal efficiency increases with the increasing of H2O2 initial concentration or UV lamp power. Meanwhile, a lower NO initial content or a higher TiO2/H2O2 solution volume will result in higher NO removal efficiency. In addition, oxygen volume fraction has a little effect.The highest NO removal efficiency is achieved at the TiO2 content of 0.75 g/L, H2O2 initial concentration of 2.5 mol/L, UV lamp power of 36 W, NO initial content of 206×10-6 and TiO2/H2O2 solution volume of 600 m L. It is beneficial for the development and application of NO removal from coal-fired flue gas with UV/TiO2/H2O2 process.
文摘The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H 2O 2/UV has beneficial effect on mineralization than O 3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.
