A unique nest-type catalyst has been designed with a nest of oxygen capture surrounding catalytic Pt centers, which shows much promoted performance, on the base of Pt/C catalyst, for oxygen reduction reaction(ORR). Th...A unique nest-type catalyst has been designed with a nest of oxygen capture surrounding catalytic Pt centers, which shows much promoted performance, on the base of Pt/C catalyst, for oxygen reduction reaction(ORR). The nest is constructed with nitrogen-doped carbon matrix(NCM), derived from the controlled carbonization of PANI precursor, to cover Pt/C catalyst. The unique structure of the catalyst(denoted as NCM■ Pt/C) has many merits. Firstly, it can capture oxygen both in air and in acidic electrolyte. Compared with naked Pt/C, it is found that, in air, the oxygen concentration within the porous nest of NCM surrounding Pt/C particles is ~13 times higher than atmospheric oxygen concentration and, in acidic electrolyte, the concentration of activated oxygen over the catalyst NCM■ Pt/C rise to~1.9 times. Secondly, the NCM nest offers a special electronic modulation on Pt centers toward modified ORR kinetics and then catalytic performances. With these merits, compared with Pt/C, the NCM■ Pt/C catalyst shows 3.2 times higher turnover frequency value and 2.9 times enhanced specific activity for ORR with half-wave potential at 0.894 V. After 50,000 sweeping cycles, the NCM■ Pt/C catalyst retains~66% mass activity and still has advantages over the fresh Pt/C catalyst. We envision that the nest-type catalyst provides a new idea for progress of practical Pt/C ORR catalyst.展开更多
Fumonisin B1(FB1)is a mycotoxin that is harmful to the nervous system;however,there is currently a lack of studies on plant compounds that alleviate the neurotoxicity of FB1.Polygonatum sibiricum polysaccharides exhib...Fumonisin B1(FB1)is a mycotoxin that is harmful to the nervous system;however,there is currently a lack of studies on plant compounds that alleviate the neurotoxicity of FB1.Polygonatum sibiricum polysaccharides exhibit neuroprotective effects,but it is unclear whether they protect against FB1-induced neurotoxicity.Here,Caenorhabditis elegans(C.elegans)was used to study the alleviation effects of P.sibiricum polysaccharide extract(PSPE)preprotection on FB1-induced neurotoxicity.PSPE pretreatment improved the behavioral deficits and neuronal damage in FB1-induced C.elegans.In addition,20-200μg/mL PSPE alleviated the oxidative damage in FB1-induced C.elegans by regulating the levels of reactive oxygen species,antioxidant enzyme activities and gene expression.Further studies have shown that PSPE pretreatment induced mitochondrial expression,increased ATP levels and mitochondrial membrane potential,and regulated mitochondrial oxidative phosphorylation and dynamics.Together,the protective effects of PSPE against FB1-induced neurotoxicity might be closely related with the reduction of oxidative stress and the regulation of mitochondria.展开更多
In this paper,a DG(Discontinuous Galerkin)method which has been widely employed in CFD(Computational Fluid Dynamics)is used to solve the twodimensional time-domain Maxwell’s equations for complex geometries on unstru...In this paper,a DG(Discontinuous Galerkin)method which has been widely employed in CFD(Computational Fluid Dynamics)is used to solve the twodimensional time-domain Maxwell’s equations for complex geometries on unstructured mesh.The element interfaces on solid boundary are treated in both curved way and straight way.Numerical tests are performed for both benchmark problems and complex cases with varying orders on a series of grids,where the high-order convergence in accuracy can be observed.Both the curved and the straight solid boundary implementation can give accurate RCS(Radar Cross-Section)results with sufficiently small mesh size,but the curved solid boundary implementation can significantly improve the accuracy when using relatively large mesh size.More importantly,this CFD-based high-order DG method for the Maxwell’s equations is very suitable for complex geometries.展开更多
A new mechanism of catalyst has been demonstrated in this article. With the interaction between carbon nitride(CN) and encapsulated nickel, the CN in the catalyst has been endowed with new active sites for the adsorpt...A new mechanism of catalyst has been demonstrated in this article. With the interaction between carbon nitride(CN) and encapsulated nickel, the CN in the catalyst has been endowed with new active sites for the adsorption and activation of hydrogen while nickel itself is physically isolated from the contact with reactive molecules. For the selective hydrogenation of acetylene in large amount of ethylene, the catalyst shows excellent ethylene selectivity than the nickel catalyst itself, which is almost totally unselective. Meanwhile, the CN itself is inactive for the reaction. The results of characterization demonstrate that pyridinic nitrogen doped in the carbon matrix should be the active sites for hydrogen dissociative adsorption. The theoretical calculations further confirm the results and provide with the detail in the electron transfer between nickel and CN in the catalyst. The current results supply a new concept for design of high performance catalyst.展开更多
Citrinin(CIT)is one of by-products by Monascus fermentation with known nephrotoxicity.Except dihydro-citrinone,no other metabolites including the possible metabolic pathways have been found in vivo metabolism.In this ...Citrinin(CIT)is one of by-products by Monascus fermentation with known nephrotoxicity.Except dihydro-citrinone,no other metabolites including the possible metabolic pathways have been found in vivo metabolism.In this study,we applied ultra-performance liquid chromatography-mass spectrometry(UPLC-MS)to analyze and identify potential CIT metabolites in the human cytochrome 450(P450)subtype system.Four new metabolites with liver microsomes incubation were first found,namely 3-hydroxy-citrinin(M1),4,5-ene-citrinin(M2),5-hydroxymethyl-citrinin(M3),and 7-hydroxy-citrinin(M4).We also found the distinguished levels of the four metabolites with the incubation of various P450 subtypes.According to the results of molecular docking prediction,it showed the metabolic correlation of CYP3A4 with M1,CYP1A2,CYP2C9,and CYP2D6 with M2,M3,and M4.The maximum level of M1 metabolite was found in the incubation with liver microsome and P450 subtypes.Moreover,M1 and M4 metabolites were found in mice’s duodenum,jejunum,ileum,liver,kidney,and hippocampus,but not M2 and M3.These results indicated the mediation of citrinin metabolism by P450s.It also suggested the concentration differences of metabolites with the incubation of different P450 subtypes.展开更多
Walnut kernel has been applied in daily diets for thousands of years with its memory enhancement effect.For further observing the effect of memory enhancement,the walnut kernel was extracted and separated into active ...Walnut kernel has been applied in daily diets for thousands of years with its memory enhancement effect.For further observing the effect of memory enhancement,the walnut kernel was extracted and separated into active parts,with the evaluation in mice.30%ethanol elution from AB-8 macroporous resin showed a decreased escape latency time and increased cumulative time and crossing frequency through the Morris test.It also increased the latency time and decreased jumps in the step-down test.These results indicated the memory enhancement effect of the fraction.After further separation and purification,four compounds were acquired with tryptamine-like structures first found in the walnut kernel,and compounds III and IV were new ones.Compound III showed decreased escape latency time,increased cumulative time,increased crossing frequency through the Morris test,and increased latency time,decreased jumps in the step-down test.Compound III also alleviated acetylcholinesterase activity and promoted acetylcholine transferase activity.In silico docking and molecular dynamic studies displayed the most polar interactions of compound III on 5-hydroxytryptamine receptor 4(5-HTR4)with the most polar interactions and the lowest binding energies,and anti-degeneration effect to monoamine oxidase A(MAO-A)with the high binding energy and sizeable steric hindrance.These results illustrated the memory enhancement of compound III in the walnut kernel,indicating more potential activities of tryptamine-like components and more applications for walnut kernel in clinical use or daily diets.展开更多
基金supported by the National Natural Science Foundation of China(91963206,21932004)the Ministry of Science and Technology of China(2017YFB0702800)the China Postdoctoral Science Foundation(2021M691512)。
文摘A unique nest-type catalyst has been designed with a nest of oxygen capture surrounding catalytic Pt centers, which shows much promoted performance, on the base of Pt/C catalyst, for oxygen reduction reaction(ORR). The nest is constructed with nitrogen-doped carbon matrix(NCM), derived from the controlled carbonization of PANI precursor, to cover Pt/C catalyst. The unique structure of the catalyst(denoted as NCM■ Pt/C) has many merits. Firstly, it can capture oxygen both in air and in acidic electrolyte. Compared with naked Pt/C, it is found that, in air, the oxygen concentration within the porous nest of NCM surrounding Pt/C particles is ~13 times higher than atmospheric oxygen concentration and, in acidic electrolyte, the concentration of activated oxygen over the catalyst NCM■ Pt/C rise to~1.9 times. Secondly, the NCM nest offers a special electronic modulation on Pt centers toward modified ORR kinetics and then catalytic performances. With these merits, compared with Pt/C, the NCM■ Pt/C catalyst shows 3.2 times higher turnover frequency value and 2.9 times enhanced specific activity for ORR with half-wave potential at 0.894 V. After 50,000 sweeping cycles, the NCM■ Pt/C catalyst retains~66% mass activity and still has advantages over the fresh Pt/C catalyst. We envision that the nest-type catalyst provides a new idea for progress of practical Pt/C ORR catalyst.
基金supported by the National Natural Science Foundation of China(32125031)the fellowship of China Postdoctoral Science Foundation(2021TQ0128)+3 种基金National first-class discipline program of Food Science and Technology(JUFSTR20180303)Collaborative Innovation Center for Food Safety and Quality Control,Science and technology project of Chongzuo City(FA2020014)Research of Polygonatum sibiricum on Efficacy Determination and Intestinal Metabolism(190790)Some strains were provided by the CGC,which is funded by NIH Office of Research Infrastructure Programs(P40 OD010440).
文摘Fumonisin B1(FB1)is a mycotoxin that is harmful to the nervous system;however,there is currently a lack of studies on plant compounds that alleviate the neurotoxicity of FB1.Polygonatum sibiricum polysaccharides exhibit neuroprotective effects,but it is unclear whether they protect against FB1-induced neurotoxicity.Here,Caenorhabditis elegans(C.elegans)was used to study the alleviation effects of P.sibiricum polysaccharide extract(PSPE)preprotection on FB1-induced neurotoxicity.PSPE pretreatment improved the behavioral deficits and neuronal damage in FB1-induced C.elegans.In addition,20-200μg/mL PSPE alleviated the oxidative damage in FB1-induced C.elegans by regulating the levels of reactive oxygen species,antioxidant enzyme activities and gene expression.Further studies have shown that PSPE pretreatment induced mitochondrial expression,increased ATP levels and mitochondrial membrane potential,and regulated mitochondrial oxidative phosphorylation and dynamics.Together,the protective effects of PSPE against FB1-induced neurotoxicity might be closely related with the reduction of oxidative stress and the regulation of mitochondria.
基金National Natural Science Foundation of China:No.11272152 and Aeronautical Science Foundation of China:No.20101552018.
文摘In this paper,a DG(Discontinuous Galerkin)method which has been widely employed in CFD(Computational Fluid Dynamics)is used to solve the twodimensional time-domain Maxwell’s equations for complex geometries on unstructured mesh.The element interfaces on solid boundary are treated in both curved way and straight way.Numerical tests are performed for both benchmark problems and complex cases with varying orders on a series of grids,where the high-order convergence in accuracy can be observed.Both the curved and the straight solid boundary implementation can give accurate RCS(Radar Cross-Section)results with sufficiently small mesh size,but the curved solid boundary implementation can significantly improve the accuracy when using relatively large mesh size.More importantly,this CFD-based high-order DG method for the Maxwell’s equations is very suitable for complex geometries.
文摘A new mechanism of catalyst has been demonstrated in this article. With the interaction between carbon nitride(CN) and encapsulated nickel, the CN in the catalyst has been endowed with new active sites for the adsorption and activation of hydrogen while nickel itself is physically isolated from the contact with reactive molecules. For the selective hydrogenation of acetylene in large amount of ethylene, the catalyst shows excellent ethylene selectivity than the nickel catalyst itself, which is almost totally unselective. Meanwhile, the CN itself is inactive for the reaction. The results of characterization demonstrate that pyridinic nitrogen doped in the carbon matrix should be the active sites for hydrogen dissociative adsorption. The theoretical calculations further confirm the results and provide with the detail in the electron transfer between nickel and CN in the catalyst. The current results supply a new concept for design of high performance catalyst.
基金supported by the National Natural Science Foundation of China(32125031)the Fundamental Research Funds for the Central Universities(JUSRP222001)the Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province,Jiangnan University.
文摘Citrinin(CIT)is one of by-products by Monascus fermentation with known nephrotoxicity.Except dihydro-citrinone,no other metabolites including the possible metabolic pathways have been found in vivo metabolism.In this study,we applied ultra-performance liquid chromatography-mass spectrometry(UPLC-MS)to analyze and identify potential CIT metabolites in the human cytochrome 450(P450)subtype system.Four new metabolites with liver microsomes incubation were first found,namely 3-hydroxy-citrinin(M1),4,5-ene-citrinin(M2),5-hydroxymethyl-citrinin(M3),and 7-hydroxy-citrinin(M4).We also found the distinguished levels of the four metabolites with the incubation of various P450 subtypes.According to the results of molecular docking prediction,it showed the metabolic correlation of CYP3A4 with M1,CYP1A2,CYP2C9,and CYP2D6 with M2,M3,and M4.The maximum level of M1 metabolite was found in the incubation with liver microsome and P450 subtypes.Moreover,M1 and M4 metabolites were found in mice’s duodenum,jejunum,ileum,liver,kidney,and hippocampus,but not M2 and M3.These results indicated the mediation of citrinin metabolism by P450s.It also suggested the concentration differences of metabolites with the incubation of different P450 subtypes.
基金This work was financially supported by the Fellowship China Postdoctoral Science Foundation(2021TQ0128)the Key Research and Development Program of Yunnan Province(202202AE090007)+1 种基金the Fundamental Research Funds for the Central Universities(JUSRP222001)the Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province,Jiangnan University.
文摘Walnut kernel has been applied in daily diets for thousands of years with its memory enhancement effect.For further observing the effect of memory enhancement,the walnut kernel was extracted and separated into active parts,with the evaluation in mice.30%ethanol elution from AB-8 macroporous resin showed a decreased escape latency time and increased cumulative time and crossing frequency through the Morris test.It also increased the latency time and decreased jumps in the step-down test.These results indicated the memory enhancement effect of the fraction.After further separation and purification,four compounds were acquired with tryptamine-like structures first found in the walnut kernel,and compounds III and IV were new ones.Compound III showed decreased escape latency time,increased cumulative time,increased crossing frequency through the Morris test,and increased latency time,decreased jumps in the step-down test.Compound III also alleviated acetylcholinesterase activity and promoted acetylcholine transferase activity.In silico docking and molecular dynamic studies displayed the most polar interactions of compound III on 5-hydroxytryptamine receptor 4(5-HTR4)with the most polar interactions and the lowest binding energies,and anti-degeneration effect to monoamine oxidase A(MAO-A)with the high binding energy and sizeable steric hindrance.These results illustrated the memory enhancement of compound III in the walnut kernel,indicating more potential activities of tryptamine-like components and more applications for walnut kernel in clinical use or daily diets.
