Lithium-sulfur(Li-S)batteries have great promise for next-generation energy storage devices due to the high theoretical specific capacity(1675 mAh g^(-1))of sulfur with chemical conversion for charge storage.However,t...Lithium-sulfur(Li-S)batteries have great promise for next-generation energy storage devices due to the high theoretical specific capacity(1675 mAh g^(-1))of sulfur with chemical conversion for charge storage.However,their practical use is hindered by the slow redox kinetics of sulfur and the“shuttle effect”arising from dissolved lithium polysulfides(LiPSs).In recent years,various carbon-based materials have served as sulfur hosts and catalysts for accelerating sulfur conversion redox kinetics and alleviating LiPS shuttling.However,they often suffer from irreversible passivation and structural changes that destroy their long-term performance.We consider the main problems limiting their stability,including excessive LiPS adsorption,passivation by insulating Li2S,and surface reconstruction,and clarify how these factors lead to capacity fade.We then outline effective strategies for achieving long-term sulfur catalysis,focusing on functional carbon,such as designing suitable carbon-supported catalyst interfaces,creating well-distributed active sites,adding cocatalysts to improve electron transfer,and using carbon-based protective layers to suppress unwanted side reactions.Using this information should enable the development of stable,high-activity catalysts capable of long-term operation under practical conditions in Li-S batteries.展开更多
This study aimed to investigate the effects of dietary guanidinoacetic acid on growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.Total 48042-day-old female ducks wer...This study aimed to investigate the effects of dietary guanidinoacetic acid on growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.Total 48042-day-old female ducks were randomly divided into four groups with six replicates and 20 ducks per replicate and fed the basal diet to the control group.The experimental groups were fed the basal diet with 400,600 and 800 mg·kg^(-1) guanidinoacetic acid,respectively.The trial lasted 48 days.Compared with the control group,(1)the body weight at 90 days and average daily gain were increased(P<0.05),the feed conservation ratio was decreased(P<0.05);(2)the dressing percentage and breast muscle percentage were increased(P<0.05);(3)the total amino acid content,polyunsaturated fatty acids to monounsaturated fatty acids ratio were increased(P<0.05)in breast and thigh muscles;(4)activities of superoxide dismutase,catalase and glutathione peroxidase enzyme were increased(P<0.05)in thigh muscles;(5)the relative expressions of superoxide dismutase 1,glutathione peroxidase 1,and catalase were significantly increased(P<0.05)in the liver.In this study,the optimum dosage of 600 mg·kg^(-1) guanidinoacetic acid improved the growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.展开更多
Na-montruorillonite （Na-MMT） was exchanged with three quaternary atkylphosphonium salts： decyl tributylphosphonium bromide （DTBPBr）, dodecyl tributylphosphonium bromide （DDTBPBr） and hexadecyl tributylphosphoni...Na-montruorillonite （Na-MMT） was exchanged with three quaternary atkylphosphonium salts： decyl tributylphosphonium bromide （DTBPBr）, dodecyl tributylphosphonium bromide （DDTBPBr） and hexadecyl tributylphosphonium bromide （HDTBPBr）, to investigate the effects of phosphonium salts species and relative molecular mass on the characteristics, morphology, thermal stability and long-acting antibacterial property of phosphonium montmorillonites. The resulting modified montmorillonites were characterized by the FTIR, XRD, TEM, and TG/DTG techniques. And minimum inhibitory concentration （MIC） was used to investigate antibacterial activity. The results show that the phosphonium salts are intercalated into Na-MMT, and the basal spacing of P-MMTs is enlarged with the increase of phosphonium salt content or the growth of alkyl chain length. DDTBP-MMT-3 with 19.83% （mass fraction of dodecyl tributylphosphonium salts, displays excellent thermal stability and long-acting antibacterial activity.展开更多
Peptides from Alcalase-hydrolyzed soybean protein hydrolysate(SPH)may hold the potential as natural antioxidants.In addition,the effect of human gastrointestinal(GI)tract on peptide bioavailability needs to be explore...Peptides from Alcalase-hydrolyzed soybean protein hydrolysate(SPH)may hold the potential as natural antioxidants.In addition,the effect of human gastrointestinal(GI)tract on peptide bioavailability needs to be explored.In this study,the impact of simulated GI digestion and transepithelial transport on various antioxidant properties of SPH were investigated.SPH displayed DPPH radical scavenging(IC50=4.22 mg/m L),ABTS·+radical scavenging(IC50=2.93 mg/m L),reducing power and metal ion-chelating activities(IC50=0.67 mg/m L).Furthermore,SPH significantly(P<0.05)inhibited the generation of intracellular reactive oxygen species(ROS)in Caco-2 cells.After simulated GI digestion,the antioxidant properties of SPH were enhanced,except for a decrease in ABTS·+radical scavenging activity.After transepithelial transport,the permeates maintained partial antioxidant activity and the LC-MS/MS data further identified the absorbed soybean peptides.These results suggest that SPH contains the antioxidant peptides that are potentially bioavailable and can be regarded as a promising source of functional food ingredients.展开更多
Soybeans are known as a promising source of bioactive peptides.However,knowledge on the antioxidant behaviors of soybean protein hydrolysate(SPH)in the human intestinal epithelium is limited.In this study,SPH was prep...Soybeans are known as a promising source of bioactive peptides.However,knowledge on the antioxidant behaviors of soybean protein hydrolysate(SPH)in the human intestinal epithelium is limited.In this study,SPH was prepared with Alcalase and subsequently ultrafiltered into four peptide fractions as SPH-I(<3 kDa),SPH-II(3~5 k Da),SPH-III(5~10 k Da)and SPH-IV(>10 kDa).The antioxidant properties of SPH and membrane fractions were investigated using different chemical assays and their protective effects against oxidative stress were evaluated using H2 O2-stressed human intestinal Caco-2 cells.Results showed that SPH-I exhibited the strongest 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging activity(IC50=2.56 mg/m L)and reducing capacity while SPH-III had the best metal ion-chelating activity(IC50=0.29 mg/m L).Both SPH and the peptide fractions dose-dependently suppressed intracellular reactive oxygen species(ROS)accumulation induced by H2O2 in Caco-2 cells,but the strongest inhibitory effect was observed for SPH-I.Amino acid(AA)results revealed that SPH-I was rich in hydrophobic and antioxidant AAs,which could contribute to its stronger antioxidant properties.Additionally,SPH-I protected Caco-2 cells from H2O2-induced oxidative stress via inhibiting lipid peroxidation and stimulating antioxidant enzyme activities.These results suggest that SPH-I and constitutive peptides can be beneficial ingredients with antioxidant properties and protective effects against ROS-mediated intestinal injury.展开更多
OBJECTIVE This study aimed to optimize polysaccharides extraction from Urena lobata L.and investigate its antioxidant activity.METHODS The mathematical model was established by re.sponse surface method(RSM) based on t...OBJECTIVE This study aimed to optimize polysaccharides extraction from Urena lobata L.and investigate its antioxidant activity.METHODS The mathematical model was established by re.sponse surface method(RSM) based on the results of single factor experiments,using polysaccha.rides extraction rate as response value,and using the ratio of water to material,cellulase concentra.tion,extraction temperature and time as experimental factors,which was used to screen optimum poly.saccharide extraction conditions from Urena lobata L..Antioxidant activity of polysaccharides was stud.ied by DPPH and ·OH free radical elimination method.RESULTS The optimum conditions obtained by RSM were as follows:the cellulase level was 10.8 g·L^(-1),extraction time duration was 72 min,the ra.tio of water to feedstock was 7 mL·g^(-1),extraction temperature was 43℃,the pH value was 5.0.Under the optimal conditions,there was a difference of less than 5% between predicted extraction rate 13.37% and experimental extraction rate 13.32%.The polysaccharide yield was most significantly af.fected by cellulase concentration,followed by extraction time,water to material ratio and extraction tem.perature.IC50 of DPPH and ·OH were 1.082 g·L^(-1) and 3.202 mg·L^(-1),respectively.Antioxidant activity of sample polysaccharides was weaker than those of vitamin C.CONCLUSION The polysaccharide extraction process from Urena lobata L.by cellulase enzymolysis approach was obtained,which was convenient and feasible,and extracted polysaccharides had good free radical scavenging activity.展开更多
Stability of tea catechins and the antioxidant properties of green tea extracts as affected by boiling-treatment from 1 to 5h were studied.Green tea catechins were partially epimerized from epi-form to nonepi-form und...Stability of tea catechins and the antioxidant properties of green tea extracts as affected by boiling-treatment from 1 to 5h were studied.Green tea catechins were partially epimerized from epi-form to nonepi-form under boiling-treatment.Total phenolic compounds of the samples under the boiling-treatment for 1 to 4h showed the same statistically significant(P > 0.05) comparing with the untreated samples and there was no significant reduction(P > 0.05) of total catechins when the green tea extracts were boiling-treated for 1h.There were no significant(P > 0.05) reduction of the antioxidant capacity when the samples were boiling-treated for 1h,no significant(P> 0.05) reduction of the scavenging ability against DPPH and O-·2when treated for 2h,and no difference on scavenging ability against OH when treated even for 5h.The results indicated that boiling-treatment for 1h had limited effect on total catehins and phenols content in green tea extracts.Green tea extracts still remained excellent in antioxidant properties and free radical scavenging activity after boiling-treated for 1 h.展开更多
A new method was presented to determine the safety factor of wall stability against overturning based on pseudo-dynamic approach. In this time-dependent method, the actual dynamic effect with variation of time and pro...A new method was presented to determine the safety factor of wall stability against overturning based on pseudo-dynamic approach. In this time-dependent method, the actual dynamic effect with variation of time and propagation of shear and primary wave velocities through the backfills was considered. Planar failure surface was considered behind the retaining wall. The results were compared with those obtained from Mononobe-Okabe theory. It is found that there is a higher value of safety factor by the present dynamic analysis. The effects of wall inclination, wall friction angle, soil friction angle and horizontal and vertical seismic coefficients on the overturning stability of retaining wall were investigated. The parametric study shows that both horizontal and vertical seismic accelerations have decreasing effect on the overturning stability of retaining wall.展开更多
In order to evaluate the seismic stability of reinforced soil walls against bearing capacity failure,the seismic safety factor of reinforced soil walls was determined by using pseudo-dynamic method,and calculated by c...In order to evaluate the seismic stability of reinforced soil walls against bearing capacity failure,the seismic safety factor of reinforced soil walls was determined by using pseudo-dynamic method,and calculated by considering different parameters,such as horizontal and vertical seismic acceleration coefficients,ratio of reinforcement length to wall height,back fill friction angle,foundation soil friction angle,soil reinforcement interface friction angle and surcharge.The parametric study shows that the seismic safety factor increases by 24-fold when the foundation soil friction angle varies from 25°to 45°,and increases by 2-fold when the soil reinforcement interface friction angle varies from 0 to 30°.That is to say,the bigger values the foundation soil and/or soil reinforcement interface friction angles have,the safer the reinforced soil walls become in the seismic design.The results were also compared with those obtained from pseudo-static method.It is found that there is a higher value of the safety factor by the present work.展开更多
In this paper,a linear/nonlinear switching active disturbance rejection control(SADRC)based decoupling control approach is proposed to deal with some difficult control problems in a class of multi-input multi-output(M...In this paper,a linear/nonlinear switching active disturbance rejection control(SADRC)based decoupling control approach is proposed to deal with some difficult control problems in a class of multi-input multi-output(MIMO)systems such as multi-variables,disturbances,and coupling,etc.Firstly,the structure and parameter tuning method of SADRC is introduced into this paper.Followed on this,virtual control variables are adopted into the MIMO systems,making the systems decoupled.Then the SADRC controller is designed for every subsystem.After this,a stability analyzed method via the Lyapunov function is proposed for the whole system.Finally,some simulations are presented to demonstrate the anti-disturbance and robustness of SADRC,and results show SADRC has a potential applications in engineering practice.展开更多
文摘Lithium-sulfur(Li-S)batteries have great promise for next-generation energy storage devices due to the high theoretical specific capacity(1675 mAh g^(-1))of sulfur with chemical conversion for charge storage.However,their practical use is hindered by the slow redox kinetics of sulfur and the“shuttle effect”arising from dissolved lithium polysulfides(LiPSs).In recent years,various carbon-based materials have served as sulfur hosts and catalysts for accelerating sulfur conversion redox kinetics and alleviating LiPS shuttling.However,they often suffer from irreversible passivation and structural changes that destroy their long-term performance.We consider the main problems limiting their stability,including excessive LiPS adsorption,passivation by insulating Li2S,and surface reconstruction,and clarify how these factors lead to capacity fade.We then outline effective strategies for achieving long-term sulfur catalysis,focusing on functional carbon,such as designing suitable carbon-supported catalyst interfaces,creating well-distributed active sites,adding cocatalysts to improve electron transfer,and using carbon-based protective layers to suppress unwanted side reactions.Using this information should enable the development of stable,high-activity catalysts capable of long-term operation under practical conditions in Li-S batteries.
基金Supported by Hainan Provincial Natural Science Foundation of China(322MS134)。
文摘This study aimed to investigate the effects of dietary guanidinoacetic acid on growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.Total 48042-day-old female ducks were randomly divided into four groups with six replicates and 20 ducks per replicate and fed the basal diet to the control group.The experimental groups were fed the basal diet with 400,600 and 800 mg·kg^(-1) guanidinoacetic acid,respectively.The trial lasted 48 days.Compared with the control group,(1)the body weight at 90 days and average daily gain were increased(P<0.05),the feed conservation ratio was decreased(P<0.05);(2)the dressing percentage and breast muscle percentage were increased(P<0.05);(3)the total amino acid content,polyunsaturated fatty acids to monounsaturated fatty acids ratio were increased(P<0.05)in breast and thigh muscles;(4)activities of superoxide dismutase,catalase and glutathione peroxidase enzyme were increased(P<0.05)in thigh muscles;(5)the relative expressions of superoxide dismutase 1,glutathione peroxidase 1,and catalase were significantly increased(P<0.05)in the liver.In this study,the optimum dosage of 600 mg·kg^(-1) guanidinoacetic acid improved the growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.
基金Projects(20676049, 20871058) supported by the National Natural Science Foundation of China Project(05200555) supported by the Natural Science Foundation of Guangdong Province, China Projects(2007B090400105, 2008A010500005) supported by the Foundation of Enterprise-University-Research Institute Cooperation from Guangdong Province and Ministry of Education of China
文摘Na-montruorillonite （Na-MMT） was exchanged with three quaternary atkylphosphonium salts： decyl tributylphosphonium bromide （DTBPBr）, dodecyl tributylphosphonium bromide （DDTBPBr） and hexadecyl tributylphosphonium bromide （HDTBPBr）, to investigate the effects of phosphonium salts species and relative molecular mass on the characteristics, morphology, thermal stability and long-acting antibacterial property of phosphonium montmorillonites. The resulting modified montmorillonites were characterized by the FTIR, XRD, TEM, and TG/DTG techniques. And minimum inhibitory concentration （MIC） was used to investigate antibacterial activity. The results show that the phosphonium salts are intercalated into Na-MMT, and the basal spacing of P-MMTs is enlarged with the increase of phosphonium salt content or the growth of alkyl chain length. DDTBP-MMT-3 with 19.83% （mass fraction of dodecyl tributylphosphonium salts, displays excellent thermal stability and long-acting antibacterial activity.
基金the financial support received from National Natural Science Foundation of China(No.31430067 and 31601475)China Postdoctoral Science Foundation funded project(No.2017M610200)Postdoctoral Foundation of Heilongjiang Province(No.LBH-Z17011)
文摘Peptides from Alcalase-hydrolyzed soybean protein hydrolysate(SPH)may hold the potential as natural antioxidants.In addition,the effect of human gastrointestinal(GI)tract on peptide bioavailability needs to be explored.In this study,the impact of simulated GI digestion and transepithelial transport on various antioxidant properties of SPH were investigated.SPH displayed DPPH radical scavenging(IC50=4.22 mg/m L),ABTS·+radical scavenging(IC50=2.93 mg/m L),reducing power and metal ion-chelating activities(IC50=0.67 mg/m L).Furthermore,SPH significantly(P<0.05)inhibited the generation of intracellular reactive oxygen species(ROS)in Caco-2 cells.After simulated GI digestion,the antioxidant properties of SPH were enhanced,except for a decrease in ABTS·+radical scavenging activity.After transepithelial transport,the permeates maintained partial antioxidant activity and the LC-MS/MS data further identified the absorbed soybean peptides.These results suggest that SPH contains the antioxidant peptides that are potentially bioavailable and can be regarded as a promising source of functional food ingredients.
基金financially supported by the National Natural Science Foundation of China(No.31430067,31601475,31571876,and 31671807)the 13th Five-Year Plan(No.2016YFD0401402)
文摘Soybeans are known as a promising source of bioactive peptides.However,knowledge on the antioxidant behaviors of soybean protein hydrolysate(SPH)in the human intestinal epithelium is limited.In this study,SPH was prepared with Alcalase and subsequently ultrafiltered into four peptide fractions as SPH-I(<3 kDa),SPH-II(3~5 k Da),SPH-III(5~10 k Da)and SPH-IV(>10 kDa).The antioxidant properties of SPH and membrane fractions were investigated using different chemical assays and their protective effects against oxidative stress were evaluated using H2 O2-stressed human intestinal Caco-2 cells.Results showed that SPH-I exhibited the strongest 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging activity(IC50=2.56 mg/m L)and reducing capacity while SPH-III had the best metal ion-chelating activity(IC50=0.29 mg/m L).Both SPH and the peptide fractions dose-dependently suppressed intracellular reactive oxygen species(ROS)accumulation induced by H2O2 in Caco-2 cells,but the strongest inhibitory effect was observed for SPH-I.Amino acid(AA)results revealed that SPH-I was rich in hydrophobic and antioxidant AAs,which could contribute to its stronger antioxidant properties.Additionally,SPH-I protected Caco-2 cells from H2O2-induced oxidative stress via inhibiting lipid peroxidation and stimulating antioxidant enzyme activities.These results suggest that SPH-I and constitutive peptides can be beneficial ingredients with antioxidant properties and protective effects against ROS-mediated intestinal injury.
基金The project supported by Natural Science Foundation of Guangxi Zhuang Autonomous Region of China (2016GXNSFBA380040) and Scientific and Technological Research Projects of Yulin City of China (20173104 and 20173102)
文摘OBJECTIVE This study aimed to optimize polysaccharides extraction from Urena lobata L.and investigate its antioxidant activity.METHODS The mathematical model was established by re.sponse surface method(RSM) based on the results of single factor experiments,using polysaccha.rides extraction rate as response value,and using the ratio of water to material,cellulase concentra.tion,extraction temperature and time as experimental factors,which was used to screen optimum poly.saccharide extraction conditions from Urena lobata L..Antioxidant activity of polysaccharides was stud.ied by DPPH and ·OH free radical elimination method.RESULTS The optimum conditions obtained by RSM were as follows:the cellulase level was 10.8 g·L^(-1),extraction time duration was 72 min,the ra.tio of water to feedstock was 7 mL·g^(-1),extraction temperature was 43℃,the pH value was 5.0.Under the optimal conditions,there was a difference of less than 5% between predicted extraction rate 13.37% and experimental extraction rate 13.32%.The polysaccharide yield was most significantly af.fected by cellulase concentration,followed by extraction time,water to material ratio and extraction tem.perature.IC50 of DPPH and ·OH were 1.082 g·L^(-1) and 3.202 mg·L^(-1),respectively.Antioxidant activity of sample polysaccharides was weaker than those of vitamin C.CONCLUSION The polysaccharide extraction process from Urena lobata L.by cellulase enzymolysis approach was obtained,which was convenient and feasible,and extracted polysaccharides had good free radical scavenging activity.
文摘Stability of tea catechins and the antioxidant properties of green tea extracts as affected by boiling-treatment from 1 to 5h were studied.Green tea catechins were partially epimerized from epi-form to nonepi-form under boiling-treatment.Total phenolic compounds of the samples under the boiling-treatment for 1 to 4h showed the same statistically significant(P > 0.05) comparing with the untreated samples and there was no significant reduction(P > 0.05) of total catechins when the green tea extracts were boiling-treated for 1h.There were no significant(P > 0.05) reduction of the antioxidant capacity when the samples were boiling-treated for 1h,no significant(P> 0.05) reduction of the scavenging ability against DPPH and O-·2when treated for 2h,and no difference on scavenging ability against OH when treated even for 5h.The results indicated that boiling-treatment for 1h had limited effect on total catehins and phenols content in green tea extracts.Green tea extracts still remained excellent in antioxidant properties and free radical scavenging activity after boiling-treated for 1 h.
基金Project(50879077) supported by the National Natural Science Foundation of China
文摘A new method was presented to determine the safety factor of wall stability against overturning based on pseudo-dynamic approach. In this time-dependent method, the actual dynamic effect with variation of time and propagation of shear and primary wave velocities through the backfills was considered. Planar failure surface was considered behind the retaining wall. The results were compared with those obtained from Mononobe-Okabe theory. It is found that there is a higher value of safety factor by the present dynamic analysis. The effects of wall inclination, wall friction angle, soil friction angle and horizontal and vertical seismic coefficients on the overturning stability of retaining wall were investigated. The parametric study shows that both horizontal and vertical seismic accelerations have decreasing effect on the overturning stability of retaining wall.
文摘In order to evaluate the seismic stability of reinforced soil walls against bearing capacity failure,the seismic safety factor of reinforced soil walls was determined by using pseudo-dynamic method,and calculated by considering different parameters,such as horizontal and vertical seismic acceleration coefficients,ratio of reinforcement length to wall height,back fill friction angle,foundation soil friction angle,soil reinforcement interface friction angle and surcharge.The parametric study shows that the seismic safety factor increases by 24-fold when the foundation soil friction angle varies from 25°to 45°,and increases by 2-fold when the soil reinforcement interface friction angle varies from 0 to 30°.That is to say,the bigger values the foundation soil and/or soil reinforcement interface friction angles have,the safer the reinforced soil walls become in the seismic design.The results were also compared with those obtained from pseudo-static method.It is found that there is a higher value of the safety factor by the present work.
基金supported by the Scientific Research Innovation Development Foundation of Army Engineering University((2019)71).
文摘In this paper,a linear/nonlinear switching active disturbance rejection control(SADRC)based decoupling control approach is proposed to deal with some difficult control problems in a class of multi-input multi-output(MIMO)systems such as multi-variables,disturbances,and coupling,etc.Firstly,the structure and parameter tuning method of SADRC is introduced into this paper.Followed on this,virtual control variables are adopted into the MIMO systems,making the systems decoupled.Then the SADRC controller is designed for every subsystem.After this,a stability analyzed method via the Lyapunov function is proposed for the whole system.Finally,some simulations are presented to demonstrate the anti-disturbance and robustness of SADRC,and results show SADRC has a potential applications in engineering practice.
基金Supported by National Natural Science Foundation of China （60974129, 70931002）, Natural Science Foundation of Jiangsu Province （BK2008188, BK2009388）, and Science Foundation of Nanjing University of Science and Technology （AB41972）
