Polymer dielectrics which possess excellent dielectric properties such as high breakdown strength,flexibility,and facile processability are considered as promising materials for advanced electrostatic capacitors.Howev...Polymer dielectrics which possess excellent dielectric properties such as high breakdown strength,flexibility,and facile processability are considered as promising materials for advanced electrostatic capacitors.However,most dielectric polymers have unsatisfactory energy storage performances at high-temperature environments.Here,polyetherimide(PEI) nanocomposite films contained with electrospun Ba(Zr_(0.79)Ti_(0.21))O_(3) nanofibers(BZTNFs) are fabricated by common solution casting method.The dielectric properties,especially the breakdown strength of the BZTNFs/PEI nanocomposites,are characterized,yet improvement is only in the small loading ones.The energy storage performance of the 0.5 vol% and1.0 vol% BZTNFs content nanocomposite is further investigated from 25 to 150℃.With the introduction of small loading BZTNFs,the dielectric permittivity and electric displacement of the nanocomposite are improved at all evaluated temperatures.The 1.0 vol% BZTNFs/PEI possesses a maximal discharged energy density of6.05 J·cm^(-3) with high efficiency of 94.9% at 25℃,then falls to 3.34 J·cm^(-3) with efficiency of 54.6% at 150℃ for the larger remnant displacement.Apparently,the relaxation ferroelectric nanofller of BZTNFs is much effective in increasing the dielectric permittivity of nanocomposite,but its capacity to restrict the migration of the charge carriers at high temperatures is weaker than that of the nanofillers with wider bandgap.The complementation of both kinds of the nanofillers probably provides an approach to available high-temperature dielectric films.展开更多
Objective:In order to elucidate the biological activity of the Co-cultured adventitious roots(ARs) of Echinacea pallida and Echinacea purpurea and provide theoretical basis for its application,and the antiinflammatory...Objective:In order to elucidate the biological activity of the Co-cultured adventitious roots(ARs) of Echinacea pallida and Echinacea purpurea and provide theoretical basis for its application,and the antiinflammatory activities and potential mechanisms of Co-cultured ARs were studied.Methods:The experimental materials were obtained by bioreactor co-culture technology and used in the activity research.In this study,mouse macrophages induced by lipopolysaccharide(LPS) were used as in vitro model.Different concentrations of AR extract(50-400 g/mL) were used to treat cells.The expression of pro-inflammatory cytokines was determined using enzyme linked immunosorbent assay.The inducible nitric oxide synthase and cyclooxygenase-2 expression,mitogen-activated protein kinase(MAPK) phosphorylation,and the inhibitor of nuclear factor-kappa B-a levels were determined by the Western blot analysis.Results:In the co-cultured ARs,total flavonoids and total caffeic acid were determined,and the contents of both bioactive compounds were significantly higher than those ARs from the single-species culture.Compared with the control group,the large amount of pro-inflammatory mediators was released after LPS stimulation.However,in the extract groups with different concentrations(25,50,and 100 g/mL),the production of these pro-inflammatory mediators was inhibited in a dose-dependent manner.Furthermore,the levels of phosphorylation of MAPK proteins,including p-p38, p-c-Jun N-terminal kinase,and p-extracellular regulated protein kinases were significantly(P <0.05) decreased in the extract groups,revealing that the AR extract probably involved in regulating the MAPK signaling pathway.Conclusion:Collectively,our findings suggested that the co-cultured ARs of E.pallida and E.purpurea can inhibit production of pro-inflammatory mediators in mouse peritoneal macrophages and possess the anti-inflammatory effect by regulating MAPK signaling pathways.展开更多
基金financially supported by Guangdong Basic and Applied Basic Research Foundation (No. 2020B1515120074)。
文摘Polymer dielectrics which possess excellent dielectric properties such as high breakdown strength,flexibility,and facile processability are considered as promising materials for advanced electrostatic capacitors.However,most dielectric polymers have unsatisfactory energy storage performances at high-temperature environments.Here,polyetherimide(PEI) nanocomposite films contained with electrospun Ba(Zr_(0.79)Ti_(0.21))O_(3) nanofibers(BZTNFs) are fabricated by common solution casting method.The dielectric properties,especially the breakdown strength of the BZTNFs/PEI nanocomposites,are characterized,yet improvement is only in the small loading ones.The energy storage performance of the 0.5 vol% and1.0 vol% BZTNFs content nanocomposite is further investigated from 25 to 150℃.With the introduction of small loading BZTNFs,the dielectric permittivity and electric displacement of the nanocomposite are improved at all evaluated temperatures.The 1.0 vol% BZTNFs/PEI possesses a maximal discharged energy density of6.05 J·cm^(-3) with high efficiency of 94.9% at 25℃,then falls to 3.34 J·cm^(-3) with efficiency of 54.6% at 150℃ for the larger remnant displacement.Apparently,the relaxation ferroelectric nanofller of BZTNFs is much effective in increasing the dielectric permittivity of nanocomposite,but its capacity to restrict the migration of the charge carriers at high temperatures is weaker than that of the nanofillers with wider bandgap.The complementation of both kinds of the nanofillers probably provides an approach to available high-temperature dielectric films.
基金supported by grants the Jilin Scientific and Technological Development Program (20180101278JC) for the financial supportthe National Natural Science Foundation of China (31370388 and 31660080)。
文摘Objective:In order to elucidate the biological activity of the Co-cultured adventitious roots(ARs) of Echinacea pallida and Echinacea purpurea and provide theoretical basis for its application,and the antiinflammatory activities and potential mechanisms of Co-cultured ARs were studied.Methods:The experimental materials were obtained by bioreactor co-culture technology and used in the activity research.In this study,mouse macrophages induced by lipopolysaccharide(LPS) were used as in vitro model.Different concentrations of AR extract(50-400 g/mL) were used to treat cells.The expression of pro-inflammatory cytokines was determined using enzyme linked immunosorbent assay.The inducible nitric oxide synthase and cyclooxygenase-2 expression,mitogen-activated protein kinase(MAPK) phosphorylation,and the inhibitor of nuclear factor-kappa B-a levels were determined by the Western blot analysis.Results:In the co-cultured ARs,total flavonoids and total caffeic acid were determined,and the contents of both bioactive compounds were significantly higher than those ARs from the single-species culture.Compared with the control group,the large amount of pro-inflammatory mediators was released after LPS stimulation.However,in the extract groups with different concentrations(25,50,and 100 g/mL),the production of these pro-inflammatory mediators was inhibited in a dose-dependent manner.Furthermore,the levels of phosphorylation of MAPK proteins,including p-p38, p-c-Jun N-terminal kinase,and p-extracellular regulated protein kinases were significantly(P <0.05) decreased in the extract groups,revealing that the AR extract probably involved in regulating the MAPK signaling pathway.Conclusion:Collectively,our findings suggested that the co-cultured ARs of E.pallida and E.purpurea can inhibit production of pro-inflammatory mediators in mouse peritoneal macrophages and possess the anti-inflammatory effect by regulating MAPK signaling pathways.
