As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol syn...As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol synthesis,In_(2)O_(3)is an ideal catalyst and has garnered significant attention.Herein,cubic In_(2)O_(3)nanoparticles were prepared via the precipitation method and evaluated for CO_(2)hydrogenation to produce methanol.During the initial 10 h of reaction,CO_(2)conversion gradually increased,accompanied by a slow decrease of methanol selectivity,and the reaction reached equilibrium after 10-20 h on stream.This activation and induction stage may be attributed to the sintering of In_(2)O_(3)nanoparticles and the creation of more oxygen vacancies on In_(2)O_(3)surfaces.Further experimental studies demonstrate that hydrogen induction created additional oxygen vacancies during the catalyst activation stage,enhancing the performance of In_(2)O_(3)catalyst for CO_(2)hydrogenation.Density functional theory calculations and microkinetic simulations further demonstrated that surfaces with higher oxygen vacancy coverages or hydroxylated surfaces formed during this induction period can enhance the reaction rate and increase the CO_(2)conversion.However,they predominantly promote the formation of CO instead of methanol,leading to reduced methanol selectivity.These predictions align well with the above-mentioned experimental observations.Our work thus provides an in-depth analysis of the induction stage of the CO_(2)hydrogenation process on In_(2)O_(3)nano-catalyst,and offers valuable insights for significantly improving the CO_(2)reactivity of In_(2)O_(3)-based catalysts while maintaining long-term stability.展开更多
In the present study, we aimed to intensively study the chemical constituents, especially organic acids from a medicinal plant Portulaca oleracea L., and screen their anti-inflammatory and quinone reductase （QR, a ph...In the present study, we aimed to intensively study the chemical constituents, especially organic acids from a medicinal plant Portulaca oleracea L., and screen their anti-inflammatory and quinone reductase （QR, a phase II detoxyfication enzyme） inductive activity. A total of 20 compounds were isolated and identified based on spectroscopic methods, as succinic acid （1）, mono-methyl succinate （2）, L-malic acid （3）, L-l-methyl malate （4）, L-4-methyl malate （5）, L-dimethyl malate （6）, L-6-ethyl citrate （7）, L-1-methyl citrate （8）, L-1,5-dimethyl citrate （9）, 4-hydroxy-5-methylfuran-3-carboxylic acid （10）, 5-hydroxymethyl-furoic acid （11）, stearic acid （12）, L-pyroglutamic acid （13）, cyclo-（tyrosine-leucine） （14）, L-isoleucine （15）, （-）-dehydrovomifoliol （16）, （-）-epiloliolide （17）, 3,4-dihydroxyphenylethanol （18）, succinimide （19）, and uracil （20）. Among them, 14 compounds （2, 4-8, 10, 11, 13-18） were isolated from P. oleracea for the first time. Compotmd 18 （12.5 μM） exhibited potent anti-inflammatory effect in lipopolysaccharide （LPS）-induced macrophage cells （RAW264.7） by reducing NO production, and it also increased QR activity in Hepa lclc7 cells. Compound 16 （50 μM） showed weak QR inductive activity. None of other compounds showed anti-inflammatory or QR inductive activities.展开更多
Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to o...Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to oxidative stress are poorly understood. In this report, the superoxide dismutase (SOD) and catalase (CAT) activities produced by these bacteria were measured, and the change of SOD and CAT activities by 20 keV N+ beam exposure was examined. Their activities were increased by N+ beam exposure from 8x 1014 ions/cm2 to 6x1015 ions/cm2.The treatment of H2O2 and [ CHC13 +CH3 CH2OH ] and the measurement of absorption spectrum showed that the increase in SOD activity was resulted from inducible activities of MnSOD in D. radiodurans AS1.633 by N+ beam exposure . These results suggested that this bacteria possess inducible defense mechanisms against the deleterious effects of oxidization.展开更多
Methylene chloride extracts of particulates from liquefied petroleum gas (LPG) combustion appliance were studied by using Ames test, micronucleus test and inducibility of pulmonary and hepatic aryl hydrocarbon hydroxy...Methylene chloride extracts of particulates from liquefied petroleum gas (LPG) combustion appliance were studied by using Ames test, micronucleus test and inducibility of pulmonary and hepatic aryl hydrocarbon hydroxylase (AHH) and glutathione S-transferase (GST) in rats. The extracts showed mutagenicity for Salmonella typhimurium strain TA98 and its derivatives TA98NR and TA98/1,8-DNP6 with or without S9 mix. The revertants in strains TA98NR and TA98/1,8-DNP6 were less than 40% and 50% of that in strain TA98 without S9 mix, respectively. Positive results were obtained in mouse bone marrow micronucleus assay. Intratracheal instillation of the extracts led to increase in pulmonary (but not hepatic) AHH and GST activities in rats. It was seen that AHH was more sensitive than GST to induction by the extracts展开更多
文摘As one of the most important industrially viable methods for carbon dioxide(CO_(2))utilization,methanol synthesis serves as a platform for production of green fuels and commodity chemicals.For sustainable methanol synthesis,In_(2)O_(3)is an ideal catalyst and has garnered significant attention.Herein,cubic In_(2)O_(3)nanoparticles were prepared via the precipitation method and evaluated for CO_(2)hydrogenation to produce methanol.During the initial 10 h of reaction,CO_(2)conversion gradually increased,accompanied by a slow decrease of methanol selectivity,and the reaction reached equilibrium after 10-20 h on stream.This activation and induction stage may be attributed to the sintering of In_(2)O_(3)nanoparticles and the creation of more oxygen vacancies on In_(2)O_(3)surfaces.Further experimental studies demonstrate that hydrogen induction created additional oxygen vacancies during the catalyst activation stage,enhancing the performance of In_(2)O_(3)catalyst for CO_(2)hydrogenation.Density functional theory calculations and microkinetic simulations further demonstrated that surfaces with higher oxygen vacancy coverages or hydroxylated surfaces formed during this induction period can enhance the reaction rate and increase the CO_(2)conversion.However,they predominantly promote the formation of CO instead of methanol,leading to reduced methanol selectivity.These predictions align well with the above-mentioned experimental observations.Our work thus provides an in-depth analysis of the induction stage of the CO_(2)hydrogenation process on In_(2)O_(3)nano-catalyst,and offers valuable insights for significantly improving the CO_(2)reactivity of In_(2)O_(3)-based catalysts while maintaining long-term stability.
基金National Natural Science Foundation of China(Grant No.81073005)Science and Technology Development Program of Shandong Province(Grant No.2014GSF119007)+2 种基金Major Project of Science and Technology of Shandong Province(Grant No.2015ZDJS04001)Young Scholars Program of Shandong University(Grant No.YSPSDU2015WLJH50)China-Australia Centre for Health Sciences Research(2015)
文摘In the present study, we aimed to intensively study the chemical constituents, especially organic acids from a medicinal plant Portulaca oleracea L., and screen their anti-inflammatory and quinone reductase （QR, a phase II detoxyfication enzyme） inductive activity. A total of 20 compounds were isolated and identified based on spectroscopic methods, as succinic acid （1）, mono-methyl succinate （2）, L-malic acid （3）, L-l-methyl malate （4）, L-4-methyl malate （5）, L-dimethyl malate （6）, L-6-ethyl citrate （7）, L-1-methyl citrate （8）, L-1,5-dimethyl citrate （9）, 4-hydroxy-5-methylfuran-3-carboxylic acid （10）, 5-hydroxymethyl-furoic acid （11）, stearic acid （12）, L-pyroglutamic acid （13）, cyclo-（tyrosine-leucine） （14）, L-isoleucine （15）, （-）-dehydrovomifoliol （16）, （-）-epiloliolide （17）, 3,4-dihydroxyphenylethanol （18）, succinimide （19）, and uracil （20）. Among them, 14 compounds （2, 4-8, 10, 11, 13-18） were isolated from P. oleracea for the first time. Compotmd 18 （12.5 μM） exhibited potent anti-inflammatory effect in lipopolysaccharide （LPS）-induced macrophage cells （RAW264.7） by reducing NO production, and it also increased QR activity in Hepa lclc7 cells. Compound 16 （50 μM） showed weak QR inductive activity. None of other compounds showed anti-inflammatory or QR inductive activities.
基金This work was supported by the National Nature Science Foundation of China! No.19605005
文摘Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to oxidative stress are poorly understood. In this report, the superoxide dismutase (SOD) and catalase (CAT) activities produced by these bacteria were measured, and the change of SOD and CAT activities by 20 keV N+ beam exposure was examined. Their activities were increased by N+ beam exposure from 8x 1014 ions/cm2 to 6x1015 ions/cm2.The treatment of H2O2 and [ CHC13 +CH3 CH2OH ] and the measurement of absorption spectrum showed that the increase in SOD activity was resulted from inducible activities of MnSOD in D. radiodurans AS1.633 by N+ beam exposure . These results suggested that this bacteria possess inducible defense mechanisms against the deleterious effects of oxidization.
文摘Methylene chloride extracts of particulates from liquefied petroleum gas (LPG) combustion appliance were studied by using Ames test, micronucleus test and inducibility of pulmonary and hepatic aryl hydrocarbon hydroxylase (AHH) and glutathione S-transferase (GST) in rats. The extracts showed mutagenicity for Salmonella typhimurium strain TA98 and its derivatives TA98NR and TA98/1,8-DNP6 with or without S9 mix. The revertants in strains TA98NR and TA98/1,8-DNP6 were less than 40% and 50% of that in strain TA98 without S9 mix, respectively. Positive results were obtained in mouse bone marrow micronucleus assay. Intratracheal instillation of the extracts led to increase in pulmonary (but not hepatic) AHH and GST activities in rats. It was seen that AHH was more sensitive than GST to induction by the extracts
