Duplex stainless steels(DSSs)are suffering from various localized corrosion attacks such as pitting,selective dissolution,crevice corrosion during their service period.It is of great value to quantitatively analyze an...Duplex stainless steels(DSSs)are suffering from various localized corrosion attacks such as pitting,selective dissolution,crevice corrosion during their service period.It is of great value to quantitatively analyze and grasp the micro-electrochemical corrosion behavior and related mechanism for DSSs on the micrometer or even smaller scales.In this work,scanning Kelvin probe force microscopy(SKPFM)and energy dispersive spectroscopy(EDS)measurements were performed to reveal the difference between the austenite phase and ferrite phase in microregion of DSS 2205.Then traditional electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization(PDP)tests were employed for micro-electrochemical characterization of DSS 2205 with different proportion phases inϕ40 andϕ10μm micro holes.Both of them can only be utilized for qualitative or semi-quantitative micro-electrochemical characterization of DSS 2205.Coulostatic perturbation method was employed for quantitative micro-electrochemical characterization of DSS 2205.What is more,the applicable conditions of coulostatic perturbation were analyzed in depth by establishing a detailed electrochemical interface circuit.A series of microregion coulostatic perturbations for DSS 2205 with different proportion phases inϕ10μm micro holes showed that as the austenite proportion increases,the corresponding polarization resistance of microregion increases linearly.展开更多
Bibenzyls,a kind of important plant polyphenols,have attracted growing attention for their broad and remarkable pharmacological activities.However,due to the low abundance in nature,uncontrollable and environmentally ...Bibenzyls,a kind of important plant polyphenols,have attracted growing attention for their broad and remarkable pharmacological activities.However,due to the low abundance in nature,uncontrollable and environmentally unfriendly chemical synthesis processes,these compounds are not readily accessible.Herein,one high-yield bibenzyl backbone-producing Escherichia coli strain was constructed by using a highly active and substrate-promiscuous bibenzyl synthase identified from Dendrobium officinale in combination with starter and extender biosynthetic enzymes.Three types of efficiently postmodifying modular strains were engineered by employing methyltransferases,prenyltransferase,and glycosyltransferase with high activity and substrate tolerance together with their corresponding donor biosynthetic modules.Structurally different bibenzyl derivatives were tandemly and/or divergently synthesized by co-culture engineering in various combination modes.Especially,a prenylated bibenzyl derivative(12)was found to be an antioxidant that exhibited potent neuroprotective activity in the cellular and rat models of ischemia stroke.RNA-seq,quantitative RT-PCR,and Western-blot analysis demonstrated that 12 could up-regulate the expression level of an apoptosis-inducing factor,mitochondria associated 3(Aifm3),suggesting that Aifm3 might be a new target in ischemic stroke therapy.This study provides a flexible plug-and-play strategy for the easy-to-implement synthesis of structurally diverse bibenzyls through a modular co-culture engineering pipeline for drug discovery.展开更多
Paeonol is a bioactive phenol present in Dioscorea japonica,Paeonia suff ruticosa and Paeonia lactifl ora.It is the main active ingredient in the traditional Chinese medicines Mudanpi and Xu Changqing.Clinical applica...Paeonol is a bioactive phenol present in Dioscorea japonica,Paeonia suff ruticosa and Paeonia lactifl ora.It is the main active ingredient in the traditional Chinese medicines Mudanpi and Xu Changqing.Clinical applications of paeonol are mainly focused on anti-infl ammatory eff ects due to its ability to act as an antioxidant,a regulator of infl ammatory enzyme activities,a modulator of infl ammatory signaling pathways and a regulator of adhesion molecules to modulate infl ammation through molecular mechanisms of action.In addition,paeonol also regulates infl ammation by regulating the metabolism of gut microbes.In this review,we searched PubMed,Web of Science,ESI and other websites using“paeonol”“infl ammation”“oxidative stress”“signaling pathways”and“gut microbiota”as keywords.We mainly referred to the relevant literature in the last decade and systematically summarized the studies on the anti-infl ammatory eff ects of paeonol to provide a reference for new drug development and clinical application of paeonol.展开更多
基金financial support from the Ministry of Science and Technology, China for the national key research and development plan (No. 2017YFB0701904)China Nuclear Power Engineering Co., Ltd. (No. KY1672)the 111 Project (No. B12012)
文摘Duplex stainless steels(DSSs)are suffering from various localized corrosion attacks such as pitting,selective dissolution,crevice corrosion during their service period.It is of great value to quantitatively analyze and grasp the micro-electrochemical corrosion behavior and related mechanism for DSSs on the micrometer or even smaller scales.In this work,scanning Kelvin probe force microscopy(SKPFM)and energy dispersive spectroscopy(EDS)measurements were performed to reveal the difference between the austenite phase and ferrite phase in microregion of DSS 2205.Then traditional electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization(PDP)tests were employed for micro-electrochemical characterization of DSS 2205 with different proportion phases inϕ40 andϕ10μm micro holes.Both of them can only be utilized for qualitative or semi-quantitative micro-electrochemical characterization of DSS 2205.Coulostatic perturbation method was employed for quantitative micro-electrochemical characterization of DSS 2205.What is more,the applicable conditions of coulostatic perturbation were analyzed in depth by establishing a detailed electrochemical interface circuit.A series of microregion coulostatic perturbations for DSS 2205 with different proportion phases inϕ10μm micro holes showed that as the austenite proportion increases,the corresponding polarization resistance of microregion increases linearly.
基金supported by the National Key Research and Development Program of China(2020YFA0908000)CAMS Innovation fund for Medical Sciences(CIFMS-2021-I2M1-028 and CIFMS-2021-I2M-1-029,China)Beijing Key Laboratory of non-Clinical Drug Metabolism and PK/PD Study(Z141102004414062,China)。
文摘Bibenzyls,a kind of important plant polyphenols,have attracted growing attention for their broad and remarkable pharmacological activities.However,due to the low abundance in nature,uncontrollable and environmentally unfriendly chemical synthesis processes,these compounds are not readily accessible.Herein,one high-yield bibenzyl backbone-producing Escherichia coli strain was constructed by using a highly active and substrate-promiscuous bibenzyl synthase identified from Dendrobium officinale in combination with starter and extender biosynthetic enzymes.Three types of efficiently postmodifying modular strains were engineered by employing methyltransferases,prenyltransferase,and glycosyltransferase with high activity and substrate tolerance together with their corresponding donor biosynthetic modules.Structurally different bibenzyl derivatives were tandemly and/or divergently synthesized by co-culture engineering in various combination modes.Especially,a prenylated bibenzyl derivative(12)was found to be an antioxidant that exhibited potent neuroprotective activity in the cellular and rat models of ischemia stroke.RNA-seq,quantitative RT-PCR,and Western-blot analysis demonstrated that 12 could up-regulate the expression level of an apoptosis-inducing factor,mitochondria associated 3(Aifm3),suggesting that Aifm3 might be a new target in ischemic stroke therapy.This study provides a flexible plug-and-play strategy for the easy-to-implement synthesis of structurally diverse bibenzyls through a modular co-culture engineering pipeline for drug discovery.
文摘Paeonol is a bioactive phenol present in Dioscorea japonica,Paeonia suff ruticosa and Paeonia lactifl ora.It is the main active ingredient in the traditional Chinese medicines Mudanpi and Xu Changqing.Clinical applications of paeonol are mainly focused on anti-infl ammatory eff ects due to its ability to act as an antioxidant,a regulator of infl ammatory enzyme activities,a modulator of infl ammatory signaling pathways and a regulator of adhesion molecules to modulate infl ammation through molecular mechanisms of action.In addition,paeonol also regulates infl ammation by regulating the metabolism of gut microbes.In this review,we searched PubMed,Web of Science,ESI and other websites using“paeonol”“infl ammation”“oxidative stress”“signaling pathways”and“gut microbiota”as keywords.We mainly referred to the relevant literature in the last decade and systematically summarized the studies on the anti-infl ammatory eff ects of paeonol to provide a reference for new drug development and clinical application of paeonol.
