Polyethersulfone(PES)can be widely used in extreme environments due to its exceptional strength and stability.In this study,molecular dynamics(MD)simulations were used to construct tribological models of PES under var...Polyethersulfone(PES)can be widely used in extreme environments due to its exceptional strength and stability.In this study,molecular dynamics(MD)simulations were used to construct tribological models of PES under varying pressures.The variations of PES molecular chains and frictional interface properties were explored for understanding microscopic tribological mechanism.The simulation results show that high pressure and high vacuum conditions reduce the coefficient of friction and wear rate.The variations in radial distribution function(RDF),relative concentration of atoms,friction interface temperature,and atomic motion velocity were analyzed.It was found that high pressure and high vacuum promote PES molecular chains moving away from the surface of the iron atomic layer,decreasing interaction energy,RDF,temperature,and velocity at the friction interface.This work offers novel methodologies and theoretical insights for studying the friction and wear of polymer composites in complex environments.展开更多
Objective The nucleolar protein PES1(Pescadillo homolog 1)plays critical roles in ribosome biogenesis and cell cycle regulation,yet its involvement in cellular senescence remains poorly understood.This study aimed to ...Objective The nucleolar protein PES1(Pescadillo homolog 1)plays critical roles in ribosome biogenesis and cell cycle regulation,yet its involvement in cellular senescence remains poorly understood.This study aimed to comprehensively investigate the functional consequences of PES1 suppression in cellular senescence and elucidate the molecular mechanisms underlying its regulatory role.Methods Initially,we assessed PES1 expression patterns in two distinct senescence models:replicative senescent mouse embryonic fibroblasts(MEFs)and doxorubicin-induced senescent human hepatocellular carcinoma HepG2 cells.Subsequently,PES1 expression was specifically downregulated using siRNA-mediated knockdown in these cell lines as well as additional relevant cell types.Cellular proliferation and senescence were assessed by EdU incorporation and SA-β-gal staining assays,respectively.The expression of senescence-associated proteins(p53,p21,and Rb)and SASP factors(IL-6,IL-1β,and IL-8)were analyzed by Western blot or qPCR.Furthermore,Northern blot and immunofluorescence were employed to evaluate pre-rRNA processing and nucleolar morphology.Results PES1 expression was significantly downregulated in senescent MEFs and HepG2 cells.PES1 knockdown resulted in decreased EdU-positive cells and increased SA-β-gal-positive cells,indicating proliferation inhibition and senescence induction.Mechanistically,PES1 suppression activated the p53-p21 pathway without affecting Rb expression,while upregulating IL-6,IL-1β,and IL-8 production.Notably,PES1 depletion impaired pre-rRNA maturation and induced nucleolar stress,as evidenced by aberrant nucleolar morphology.Conclusion Our findings demonstrate that PES1 deficiency triggers nucleolar stress and promotes p53-dependent(but Rb-independent)cellular senescence,highlighting its crucial role in maintaining nucleolar homeostasis and regulating senescence-associated pathways.展开更多
The payment for ecosystem services(PES)has attracted increasing attentions as a strategy to avoid the poverty-environment trap.It is little documented how the PES implementation affects the participation of stakeholde...The payment for ecosystem services(PES)has attracted increasing attentions as a strategy to avoid the poverty-environment trap.It is little documented how the PES implementation affects the participation of stakeholders from the perspective of coupled human and natural system.To address this issue,we first conceptualized and analyzed the trade-off among the stakeholders using evolutionary game theory under Grain for Green Program(GFGP).The evolutionary stable strategies and the stability dynamics of the conceptualized model were obtained.An integrated social-ecological investigation was performed in a rural community of northwest China at the first phase of GFGP(10-year period)to verify the conceptualized model.The results of evolutionary game analysis showed that improving substitutive off-farm opportunities and income levels can strategically coordinate the so-called inherent conflicts between livelihood development and ecosystem conservation.The behavior strategies of farmers regarding their cognition,adoption and responses(practical implementation)were siginficantly affected by the GFGP.Simultaneously,forest cover and per capita bio-capacity were evidently improved under the conservation program.Relative contribution rate analyses showed that those farmer households with more farmlands of low yield potential(larger area of sloping farmlands)tended to have lower total income.Therefore,the total incomes of the households participating in the program were significantly increased at the ending year of GFGP,relative to the starting year(P<0.05).Considering the key contributions of household income and farming system to ecosystem conservation,it was needed to design further supporting policies for small farmers.The findings highlight the key role of PES on adaptive livelihood management in avoiding the poverty-environment trap in fragile ecosystems where small farmers are dominant.展开更多
Ultrafiltration membranes were prepared using phenolphthalein polyarylethersulfone (PES-C),polyethersulfone (PES) and poly(phthalazinone ether sulfone ketone) (PPESK) as polymers and NMP,DMAc,DMF and DMSO as solvents ...Ultrafiltration membranes were prepared using phenolphthalein polyarylethersulfone (PES-C),polyethersulfone (PES) and poly(phthalazinone ether sulfone ketone) (PPESK) as polymers and NMP,DMAc,DMF and DMSO as solvents by immersion precipitation via phase inversion.Experimental data of thermodynamic properties of the polymer solutions and kinetic process of membrane formation were reported.For polymer solutions with good solvents,the sequence of the viscous flow activation energy (E_η) was coincident with tha...展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52275460)the Key Research and Development Program Academician Cooperation Project of Tianjin(Grant No.24YFYSHZ00270)the Tianjin University of Technology Graduate Research(Grant No.YJ2303).
摘要Polyethersulfone(PES)can be widely used in extreme environments due to its exceptional strength and stability.In this study,molecular dynamics(MD)simulations were used to construct tribological models of PES under varying pressures.The variations of PES molecular chains and frictional interface properties were explored for understanding microscopic tribological mechanism.The simulation results show that high pressure and high vacuum conditions reduce the coefficient of friction and wear rate.The variations in radial distribution function(RDF),relative concentration of atoms,friction interface temperature,and atomic motion velocity were analyzed.It was found that high pressure and high vacuum promote PES molecular chains moving away from the surface of the iron atomic layer,decreasing interaction energy,RDF,temperature,and velocity at the friction interface.This work offers novel methodologies and theoretical insights for studying the friction and wear of polymer composites in complex environments.
摘要Objective The nucleolar protein PES1(Pescadillo homolog 1)plays critical roles in ribosome biogenesis and cell cycle regulation,yet its involvement in cellular senescence remains poorly understood.This study aimed to comprehensively investigate the functional consequences of PES1 suppression in cellular senescence and elucidate the molecular mechanisms underlying its regulatory role.Methods Initially,we assessed PES1 expression patterns in two distinct senescence models:replicative senescent mouse embryonic fibroblasts(MEFs)and doxorubicin-induced senescent human hepatocellular carcinoma HepG2 cells.Subsequently,PES1 expression was specifically downregulated using siRNA-mediated knockdown in these cell lines as well as additional relevant cell types.Cellular proliferation and senescence were assessed by EdU incorporation and SA-β-gal staining assays,respectively.The expression of senescence-associated proteins(p53,p21,and Rb)and SASP factors(IL-6,IL-1β,and IL-8)were analyzed by Western blot or qPCR.Furthermore,Northern blot and immunofluorescence were employed to evaluate pre-rRNA processing and nucleolar morphology.Results PES1 expression was significantly downregulated in senescent MEFs and HepG2 cells.PES1 knockdown resulted in decreased EdU-positive cells and increased SA-β-gal-positive cells,indicating proliferation inhibition and senescence induction.Mechanistically,PES1 suppression activated the p53-p21 pathway without affecting Rb expression,while upregulating IL-6,IL-1β,and IL-8 production.Notably,PES1 depletion impaired pre-rRNA maturation and induced nucleolar stress,as evidenced by aberrant nucleolar morphology.Conclusion Our findings demonstrate that PES1 deficiency triggers nucleolar stress and promotes p53-dependent(but Rb-independent)cellular senescence,highlighting its crucial role in maintaining nucleolar homeostasis and regulating senescence-associated pathways.
基金financially supported by the National Natural Science Foundation of China(32161143012 and 32401359)Fundamental Research Funds for the Central Universities(lzujbky-2024-jdzx11 and lzujbky-2024-ydyl04).
摘要The payment for ecosystem services(PES)has attracted increasing attentions as a strategy to avoid the poverty-environment trap.It is little documented how the PES implementation affects the participation of stakeholders from the perspective of coupled human and natural system.To address this issue,we first conceptualized and analyzed the trade-off among the stakeholders using evolutionary game theory under Grain for Green Program(GFGP).The evolutionary stable strategies and the stability dynamics of the conceptualized model were obtained.An integrated social-ecological investigation was performed in a rural community of northwest China at the first phase of GFGP(10-year period)to verify the conceptualized model.The results of evolutionary game analysis showed that improving substitutive off-farm opportunities and income levels can strategically coordinate the so-called inherent conflicts between livelihood development and ecosystem conservation.The behavior strategies of farmers regarding their cognition,adoption and responses(practical implementation)were siginficantly affected by the GFGP.Simultaneously,forest cover and per capita bio-capacity were evidently improved under the conservation program.Relative contribution rate analyses showed that those farmer households with more farmlands of low yield potential(larger area of sloping farmlands)tended to have lower total income.Therefore,the total incomes of the households participating in the program were significantly increased at the ending year of GFGP,relative to the starting year(P<0.05).Considering the key contributions of household income and farming system to ecosystem conservation,it was needed to design further supporting policies for small farmers.The findings highlight the key role of PES on adaptive livelihood management in avoiding the poverty-environment trap in fragile ecosystems where small farmers are dominant.
基金supported by the Major State Basic Research Program of China (No.2009CB623404)National Natural Science Foundation of China (Nos.20736003,20676067)+1 种基金National High Technology Research and Development Program of China (No.2007AA06Z317)Foundation of Ministry of Education of China (No.20070003130).
摘要Ultrafiltration membranes were prepared using phenolphthalein polyarylethersulfone (PES-C),polyethersulfone (PES) and poly(phthalazinone ether sulfone ketone) (PPESK) as polymers and NMP,DMAc,DMF and DMSO as solvents by immersion precipitation via phase inversion.Experimental data of thermodynamic properties of the polymer solutions and kinetic process of membrane formation were reported.For polymer solutions with good solvents,the sequence of the viscous flow activation energy (E_η) was coincident with tha...