Carbon black(CB)is a vital constituent of airborne pollutants,comprising diesel exhaust and fine particulate matter(PM_(2.5)),aswell as a prevalent manufacturingmaterial.CBwas known to cause pulmonary dysfunction and ...Carbon black(CB)is a vital constituent of airborne pollutants,comprising diesel exhaust and fine particulate matter(PM_(2.5)),aswell as a prevalent manufacturingmaterial.CBwas known to cause pulmonary dysfunction and fibrosis.However,the detailedmolecular mechanisms underlying fibrosis development are poorly understood.In this study,18 C57BL/6mice were randomized into two groups and exposed to CB and filtered air(FA)for 28 days,with 6 hr/day and 7 days perweek exposure regimen,respectively.The human normal bronchial epithelial cell line(BEAS-2B)was subjected to CB treatment for 24 h in vitro,with CB concentrations in 0,50,100,and 200μg/mL.Our study indicated that exposure to CB resulted in a reduction in lung function and the development of pulmonary fibrosis in mice.Furthermore,our results showed cytoskeleton rearrangement and epithelial-mesenchymal transition(EMT)phenotype in BEAS-2B cells were happened,after CB exposure.Subsequent studies revealed that elevated expression of THBS2 after CB primarily contributed to the development of pulmonary fibrosis.The research findings from both in vivo and in vitro studies provided evidence that piR-713551 was involved in CB exposure-induced EMT by targeting the THBS2 gene and activating theβ-catenin pathway.Mechanically,piR-713551/PIWIL4 complex activated the THBS2 transcription by recruitment of histone demethyltransferase KDM4A to reduce H3K9me3 modification at the THBS2 gene promoter.Conclusively,our research showed that CB exposure could activate EMT and lead pulmonary fibrosis which was modulated by piR-713551/PIWIL4 targeting THBS2.展开更多
One of the key elements influencing the performance of a carbon trading system, are the methods of allocating the initial CO2 emissions. This paper tries to use a quantitative description method to analyze the influen...One of the key elements influencing the performance of a carbon trading system, are the methods of allocating the initial CO2 emissions. This paper tries to use a quantitative description method to analyze the influence of the different allocation methods on the level of CO2 emissions based on the seven pilot trading markets from 2009 to 2013 in China. The results show that different methods bring about various degrees of impacts, through direct and indirect constraint mechanism, influence the CO2 emission cut finally. Although due to the complexity of the direct and indirect constraint mechanism, attempting to compare the effects of different allocation methods is difficult by using the data of carbon emission cut from seven pilot markets in China, the paper shows that the allowance allocation methods, through the constraints imposed on enterprises, significantly reduce regional carbon emissions.展开更多
Phonon-assisted photon upconversion(UPC)is an anti-Stokes process in which incident photons achieve higher energy emission by absorbing phonons.This letter studies phonon-assisted UPC in twisted 2D semiconductors,in w...Phonon-assisted photon upconversion(UPC)is an anti-Stokes process in which incident photons achieve higher energy emission by absorbing phonons.This letter studies phonon-assisted UPC in twisted 2D semiconductors,in which an inverted contrast between UPC and conventional photoluminescence(PL)of WSe2 twisted bilayer is emergent.A 4-fold UPC enhancement is achieved in 5.5°twisted bilayer while PL weakens by half.Reduced interlayer exciton conversion efficiency driven by lattice relaxation,along with enhanced pump efficiency resulting from spectral redshift,lead to the rotation-angle-dependent UPC enhancement.The counterintuitive phenomenon provides a novel insight into a unique way that twisted angle affects UPC and light-matter interactions in 2D semiconductors.Furthermore,the UPC enhancement platform with various superimposable means offers an effective method for lighting bilayers and expanding the application prospect of 2D stacked van der Waals devices.展开更多
Two dimensional excitonic devices are of great potential to overcome the dilemma of response time and integration in current generation of electron or/and photon based systems.The ultrashort diffusion length of excito...Two dimensional excitonic devices are of great potential to overcome the dilemma of response time and integration in current generation of electron or/and photon based systems.The ultrashort diffusion length of exciton arising from ultrafast relaxation and low carrier mobility greatly discounts the performance of excitonic devices.Phonon scattering and exciton localization are crucial to understand the modulation of exciton flux in two dimensional disorder energy landscape,which still remain elusive.Here,we report an optimized scheme for exciton diffusion and relaxation dominated by phonon scattering and disorder potentials in WSe2 monolayers.The effective diffusion coefficient is enhanced by>200%at 280 K.The excitons tend to be localized by disorder potentials accompanied by the steadily weakening of phonon scattering when temperature drops to 260 K,and the onset of exciton localization brings forward as decreasing temperature.These findings identify that phonon scattering and disorder potentials are of great importance for long-range exciton diffusion and thermal management in exciton based systems,and lay a firm foundation for the development of functional excitonic devices.展开更多
基金supported by the National Natural Science Foundation of China(Nos.81973074,92043202,82204075,and 82204074).
文摘Carbon black(CB)is a vital constituent of airborne pollutants,comprising diesel exhaust and fine particulate matter(PM_(2.5)),aswell as a prevalent manufacturingmaterial.CBwas known to cause pulmonary dysfunction and fibrosis.However,the detailedmolecular mechanisms underlying fibrosis development are poorly understood.In this study,18 C57BL/6mice were randomized into two groups and exposed to CB and filtered air(FA)for 28 days,with 6 hr/day and 7 days perweek exposure regimen,respectively.The human normal bronchial epithelial cell line(BEAS-2B)was subjected to CB treatment for 24 h in vitro,with CB concentrations in 0,50,100,and 200μg/mL.Our study indicated that exposure to CB resulted in a reduction in lung function and the development of pulmonary fibrosis in mice.Furthermore,our results showed cytoskeleton rearrangement and epithelial-mesenchymal transition(EMT)phenotype in BEAS-2B cells were happened,after CB exposure.Subsequent studies revealed that elevated expression of THBS2 after CB primarily contributed to the development of pulmonary fibrosis.The research findings from both in vivo and in vitro studies provided evidence that piR-713551 was involved in CB exposure-induced EMT by targeting the THBS2 gene and activating theβ-catenin pathway.Mechanically,piR-713551/PIWIL4 complex activated the THBS2 transcription by recruitment of histone demethyltransferase KDM4A to reduce H3K9me3 modification at the THBS2 gene promoter.Conclusively,our research showed that CB exposure could activate EMT and lead pulmonary fibrosis which was modulated by piR-713551/PIWIL4 targeting THBS2.
文摘One of the key elements influencing the performance of a carbon trading system, are the methods of allocating the initial CO2 emissions. This paper tries to use a quantitative description method to analyze the influence of the different allocation methods on the level of CO2 emissions based on the seven pilot trading markets from 2009 to 2013 in China. The results show that different methods bring about various degrees of impacts, through direct and indirect constraint mechanism, influence the CO2 emission cut finally. Although due to the complexity of the direct and indirect constraint mechanism, attempting to compare the effects of different allocation methods is difficult by using the data of carbon emission cut from seven pilot markets in China, the paper shows that the allowance allocation methods, through the constraints imposed on enterprises, significantly reduce regional carbon emissions.
基金supports from the National Key Research and Development Program of China(2020YFA0211300)National Science Foundation of China(grant Nos.62225501,12027807)+1 种基金Bejing Natural Science Foundation(grant Nos.Z180011)High-performance Computing Platform of Peking University.
文摘Phonon-assisted photon upconversion(UPC)is an anti-Stokes process in which incident photons achieve higher energy emission by absorbing phonons.This letter studies phonon-assisted UPC in twisted 2D semiconductors,in which an inverted contrast between UPC and conventional photoluminescence(PL)of WSe2 twisted bilayer is emergent.A 4-fold UPC enhancement is achieved in 5.5°twisted bilayer while PL weakens by half.Reduced interlayer exciton conversion efficiency driven by lattice relaxation,along with enhanced pump efficiency resulting from spectral redshift,lead to the rotation-angle-dependent UPC enhancement.The counterintuitive phenomenon provides a novel insight into a unique way that twisted angle affects UPC and light-matter interactions in 2D semiconductors.Furthermore,the UPC enhancement platform with various superimposable means offers an effective method for lighting bilayers and expanding the application prospect of 2D stacked van der Waals devices.
基金National Key Research and Development Program of China(Grant No.2017YFA0206000)eijing Natural Science Foundation(Grant No.Z180011)+1 种基金National Science Foundation of China(Grant Nos.12027807,12104241 and 61521004)roject funded by China Postdoctoral Science Foundation(Grant No.2019M660283)。
文摘Two dimensional excitonic devices are of great potential to overcome the dilemma of response time and integration in current generation of electron or/and photon based systems.The ultrashort diffusion length of exciton arising from ultrafast relaxation and low carrier mobility greatly discounts the performance of excitonic devices.Phonon scattering and exciton localization are crucial to understand the modulation of exciton flux in two dimensional disorder energy landscape,which still remain elusive.Here,we report an optimized scheme for exciton diffusion and relaxation dominated by phonon scattering and disorder potentials in WSe2 monolayers.The effective diffusion coefficient is enhanced by>200%at 280 K.The excitons tend to be localized by disorder potentials accompanied by the steadily weakening of phonon scattering when temperature drops to 260 K,and the onset of exciton localization brings forward as decreasing temperature.These findings identify that phonon scattering and disorder potentials are of great importance for long-range exciton diffusion and thermal management in exciton based systems,and lay a firm foundation for the development of functional excitonic devices.
