Methyl jasmonate(MeJA)is a plant-signalling molecule that plays significant roles in stress reactions and defence responses.The goal of this study was to characterize the effects of exogenous MeJA application on the r...Methyl jasmonate(MeJA)is a plant-signalling molecule that plays significant roles in stress reactions and defence responses.The goal of this study was to characterize the effects of exogenous MeJA application on the resistance of postharvest pear fruit to blue mould rot caused by Penicillium expansum and investigate the mechanism underlying the observed effects of MeJA application.MeJA treatment effectively reduced the lesion diameter of blue mould rot in pear fruit.Furthermore,MeJA significantly enhanced the activities of antioxidant and defence-related enzymes,such as polyphenol oxidase(PPO),superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),β-1,3 glucanase(GLU)and chitinase(CHI);total phenol content also increased,and membrane lipid peroxidation decreased.MeJA treatment promoted the expression of PpPPO,Cu-ZnSOD,PpPOD,PpCAT,PpCHI and PpGLU.Overall,this experiment suggested that MeJA-induced pear fruit resistance against blue mould rot may be related to the enhanced activities of defence enzymes and gene expression.展开更多
Cancer is a predominant culprit behind worldwide death and accounts for up to 10 million deaths every year.Chemotherapy is the primary therapeutic method employed for cancer in clinical settings and is essential in co...Cancer is a predominant culprit behind worldwide death and accounts for up to 10 million deaths every year.Chemotherapy is the primary therapeutic method employed for cancer in clinical settings and is essential in controlling tumor progression.Despite the advances in this field,tumor invasion and metastasis during treatment remain a significant cause of treatment failure.Nevertheless,the underlying mechanisms involving such a disappointing phenomenon are still not fully elucidated.Vinorelbine(VNB)extends the lifespan of many cancer patients in the clinic as an emerging chemotherapy drug approved by Food and Drug Administration(FDA).However,VNB-induced tumor metastasis is still an intractable problem,which may be closely related to the abnormal oxidative stress generated during VNB-mediated treatment.Hence,the study aims to construct a reductive nanosystem loaded with VNB,called VNB-VNP,to improve cancer cure rates and reduce tumor metastasis.With the reductive component vitamin E,VNB-VNP can effectively reduce oxidative stress and significantly outperform free VNB in preventing tumor progression.The transcriptome analysis shows that VNB-VNP can alleviate the over-expression of ectonucleotide pyrophosphatase/phosphodiesterase 2(ENPP2),which may be the main reason why VNB-VNP can inhibit tumor invasion and metastasis.Overall,the research designs a new platform for VNB treatment,which demonstrates promising efficacy in inhibiting neoplastic progression and identifies a new mechanism associated with VNB-induced tumor metastasis,which may offer several valuable references for enhancing chemotherapy efficacy in clinical anti-tumor therapy.展开更多
The traditional evaporator of water source heat pump system is easy to freeze when the water source temperature is too low in winter.A novel ice source heat pump system is proposed,which can use low temperature surfac...The traditional evaporator of water source heat pump system is easy to freeze when the water source temperature is too low in winter.A novel ice source heat pump system is proposed,which can use low temperature surface water to supply heat to buildings.One of the key problems for safe transportation is velocity range of ice slurry in ice outlet pipeline.In order to study the critical flow velocity of ice slurry in the pipe,an Euler model of horizontal straight pipe and 90°elbow pipe were established by Fluent software.The influence of five factors on the critical flow velocity of two kinds of pipes,including initial ice packing fraction,ice particle size,pipe diameter,length of straight pipe and radius curvature of elbow was studied.It found that the initial ice content should be controlled from 10%to 15%.The inlet flow rate was 20%higher than the critical flow rate under the most unfavorable condition.Ice particle size was less than 0.2 mm.The total length of ice discharge pipeline was less than 50 m.Curvature radius of the bend should be met the minimum requirements of the specification of the pipe used.展开更多
The lockdown policy deals a severe blow to the economy and greatly reduces the nitrogen oxides(NOx)emission in China when the coronavirus 2019 spreads widely in early 2020.Here we use satellite observations from Tropo...The lockdown policy deals a severe blow to the economy and greatly reduces the nitrogen oxides(NOx)emission in China when the coronavirus 2019 spreads widely in early 2020.Here we use satellite observations from Tropospheric Monitoring Instrument to study the year-round variation of the nitrogen dioxide(NO_(2))tropospheric vertical column density(TVCD)in 2020.The NO_(2)TVCD reveals a sharp drop,followed by small fluctuations and then a strong rebound when compared to 2019.By the end of 2020,the annual average NO_(2)TVCD declines by only 3.4%in Chinamainland,much less than the reduction of 24.1%in the lockdown period.On the basis of quantitative analysis,we find the rebound of NO_(2)TVCD is mainly caused by the rapid recovery of economy especially in the fourth quarter,when contribution of industry and power plant on NO_(2)TVCD continues to rise.This revenge bounce of NO_(2)indicates the emission reduction of NOx in lockdown period is basically offset by the recovery of economy,revealing the fact that China’s economic development and NOx emissions are still not decoupled.More efforts are still required to stimulate low-pollution development.展开更多
Recent increases in emissions from freight transport have caused strong concerns about air quality in Pakistan,following the rapid development of projects related to the China-Pakistan Economic Corridor(CPEC).This stu...Recent increases in emissions from freight transport have caused strong concerns about air quality in Pakistan,following the rapid development of projects related to the China-Pakistan Economic Corridor(CPEC).This study reported the first measurements of on-road truck emissions in Pakistan and investigated their dependence on altitude along CPEC routes.Emissions from 70 trucks were measured on CPEC highways located in Islamabad(540 m above sea level),Sost(2800 m above sea level),and at the Khunjerab Pass(4693 m above sea level).Calculated emission factors for carbon monoxide,hydrocarbons,and nitrogen oxides from heavy-duty trucks in Islamabad were 12.94±1.46,15.21±1.67,and 10.69±1.34 g km^(-1)(95%confidence level),respectively,for pre-Pak-II trucks,and 12.75±2.80,14.24±3.53,and 10.24±2.34 g km^(-1)(95%confidence level),respectively,for Pak-II trucks,representing 2e20 times higher values than the emission standards in Pakistan and India.An altitude increase of approximately 4000 m,with the associated changes in meteorology and fleet characteristics,induced an average increase of 103.6%,86.3%,124.5%,and 133.6%in the emission factors of carbon monoxide,hydrocarbons,nitrogen oxides,and carbon dioxide,respectively.Moreover,on-road emissions along the CPEC were mainly influenced by truck types.This study will support the budget evaluation of transport emissions from the CPEC trade fleet.展开更多
Hematite(α-Fe_(2)O_(3))constitutes one of the most promising photoanode materials for oxygen evolution reaction(OER).Recent research on Fe_(2)O_(3) have found a fast OER rate dependence on surface hole density,sugges...Hematite(α-Fe_(2)O_(3))constitutes one of the most promising photoanode materials for oxygen evolution reaction(OER).Recent research on Fe_(2)O_(3) have found a fast OER rate dependence on surface hole density,suggesting a multisite reaction pathway.However,the effect of heteroatom in Fe_(2)O_(3) on the multisite mechanism is still poorly understood.Herein we synthesized Fe_(2)O_(3) on Ti substrates(Fe_(2)O_(3)/Ti)to study the oxygen intermediates of OER by light-dark electrochemical scans.We identified the Fe-OH species disappeared and Ti-OH intermediates appeared on Fe_(2)O_(3)/Ti when pH=11‒14,which significantly improved the OER performance of Fe_(2)O_(3)/Ti.Combined with the density functional theory calculations,we propose that Ti atom acts as cocatalyst site and captures proton from neighboring Fe-OH species under highly alkaline condition,thereby promoting the coupling of Fe=O and reducing the energy barrier of the non-electrochemical step.Our work provides a new insight into the role of heteroatom in OER multisite mechanism based on clarifying the reaction intermediates.展开更多
Surface monitoring, vertical atmospheric column observation, and simulation using chemical transportation models are three dominant approaches for perception of fine particles with diameters less than 2.5 micrometers(...Surface monitoring, vertical atmospheric column observation, and simulation using chemical transportation models are three dominant approaches for perception of fine particles with diameters less than 2.5 micrometers(PM2.5) concentration. Here we explored an imagebased methodology with a deep learning approach and machine learning approach to extend the ability on PM2.5 perception. Using 6976 images combined with daily weather conditions and hourly time data in Shanghai(2016), trained by hourly surface monitoring concentrations, an end-to-end model consisting of convolutional neural network and gradient boosting machine(GBM) was constructed. The mean absolute error, the root-mean-square error and the R-squared for PM2.5 concentration estimation using our proposed method is 3.56, 10.02, and 0.85 respectively. The transferability analysis showed that networks trained in Shanghai, fine-tuned with only 10% of images in other locations, achieved performances similar to ones from trained on data from target locations themselves. The sensitivity of different regions in the image to PM2.5 concentration was also quantified through the analysis of feature importance in GBM. All the required inputs in this study are commonly available, which greatly improved the accessibility of PM2.5 concentration for placed and period with no surface observation. And this study makes an exploratory attempt on pollution monitoring using graph theory and deep learning approach.展开更多
基金funded by the National Natural Science Foundation of China(32160399)Jiangxi Province Fruit and Vegetable Postharvest Processing Key Technology and Quality and Safety Collaborative Innovation Center Project(JXGS-03).
文摘Methyl jasmonate(MeJA)is a plant-signalling molecule that plays significant roles in stress reactions and defence responses.The goal of this study was to characterize the effects of exogenous MeJA application on the resistance of postharvest pear fruit to blue mould rot caused by Penicillium expansum and investigate the mechanism underlying the observed effects of MeJA application.MeJA treatment effectively reduced the lesion diameter of blue mould rot in pear fruit.Furthermore,MeJA significantly enhanced the activities of antioxidant and defence-related enzymes,such as polyphenol oxidase(PPO),superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),β-1,3 glucanase(GLU)and chitinase(CHI);total phenol content also increased,and membrane lipid peroxidation decreased.MeJA treatment promoted the expression of PpPPO,Cu-ZnSOD,PpPOD,PpCAT,PpCHI and PpGLU.Overall,this experiment suggested that MeJA-induced pear fruit resistance against blue mould rot may be related to the enhanced activities of defence enzymes and gene expression.
基金supported by the National Natural Science Foundation of China(No.81973246)Public Welfare Project of Zhejiang Natural Science Foundation(No.GF22H308848).
文摘Cancer is a predominant culprit behind worldwide death and accounts for up to 10 million deaths every year.Chemotherapy is the primary therapeutic method employed for cancer in clinical settings and is essential in controlling tumor progression.Despite the advances in this field,tumor invasion and metastasis during treatment remain a significant cause of treatment failure.Nevertheless,the underlying mechanisms involving such a disappointing phenomenon are still not fully elucidated.Vinorelbine(VNB)extends the lifespan of many cancer patients in the clinic as an emerging chemotherapy drug approved by Food and Drug Administration(FDA).However,VNB-induced tumor metastasis is still an intractable problem,which may be closely related to the abnormal oxidative stress generated during VNB-mediated treatment.Hence,the study aims to construct a reductive nanosystem loaded with VNB,called VNB-VNP,to improve cancer cure rates and reduce tumor metastasis.With the reductive component vitamin E,VNB-VNP can effectively reduce oxidative stress and significantly outperform free VNB in preventing tumor progression.The transcriptome analysis shows that VNB-VNP can alleviate the over-expression of ectonucleotide pyrophosphatase/phosphodiesterase 2(ENPP2),which may be the main reason why VNB-VNP can inhibit tumor invasion and metastasis.Overall,the research designs a new platform for VNB treatment,which demonstrates promising efficacy in inhibiting neoplastic progression and identifies a new mechanism associated with VNB-induced tumor metastasis,which may offer several valuable references for enhancing chemotherapy efficacy in clinical anti-tumor therapy.
文摘The traditional evaporator of water source heat pump system is easy to freeze when the water source temperature is too low in winter.A novel ice source heat pump system is proposed,which can use low temperature surface water to supply heat to buildings.One of the key problems for safe transportation is velocity range of ice slurry in ice outlet pipeline.In order to study the critical flow velocity of ice slurry in the pipe,an Euler model of horizontal straight pipe and 90°elbow pipe were established by Fluent software.The influence of five factors on the critical flow velocity of two kinds of pipes,including initial ice packing fraction,ice particle size,pipe diameter,length of straight pipe and radius curvature of elbow was studied.It found that the initial ice content should be controlled from 10%to 15%.The inlet flow rate was 20%higher than the critical flow rate under the most unfavorable condition.Ice particle size was less than 0.2 mm.The total length of ice discharge pipeline was less than 50 m.Curvature radius of the bend should be met the minimum requirements of the specification of the pipe used.
基金supported by the National Natural Science Foundation of China(Nos.41822505 and 42061130213)the special fund from the State Key Joint Laboratory of Environment Simulation and Pollution Control(No.20L01ESPC)H.L.is supported by the Royal Society of UK through a Newton Advanced Fellowship(NAF\R1\201166).
文摘The lockdown policy deals a severe blow to the economy and greatly reduces the nitrogen oxides(NOx)emission in China when the coronavirus 2019 spreads widely in early 2020.Here we use satellite observations from Tropospheric Monitoring Instrument to study the year-round variation of the nitrogen dioxide(NO_(2))tropospheric vertical column density(TVCD)in 2020.The NO_(2)TVCD reveals a sharp drop,followed by small fluctuations and then a strong rebound when compared to 2019.By the end of 2020,the annual average NO_(2)TVCD declines by only 3.4%in Chinamainland,much less than the reduction of 24.1%in the lockdown period.On the basis of quantitative analysis,we find the rebound of NO_(2)TVCD is mainly caused by the rapid recovery of economy especially in the fourth quarter,when contribution of industry and power plant on NO_(2)TVCD continues to rise.This revenge bounce of NO_(2)indicates the emission reduction of NOx in lockdown period is basically offset by the recovery of economy,revealing the fact that China’s economic development and NOx emissions are still not decoupled.More efforts are still required to stimulate low-pollution development.
基金supported by the National Natural Science Foundation of China(grant numbers 41822505 and 42061130213 for H.L.)supported by the Royal Society of the United Kingdom through a Newton Advanced Fellowship(NAF\R1\201166).
文摘Recent increases in emissions from freight transport have caused strong concerns about air quality in Pakistan,following the rapid development of projects related to the China-Pakistan Economic Corridor(CPEC).This study reported the first measurements of on-road truck emissions in Pakistan and investigated their dependence on altitude along CPEC routes.Emissions from 70 trucks were measured on CPEC highways located in Islamabad(540 m above sea level),Sost(2800 m above sea level),and at the Khunjerab Pass(4693 m above sea level).Calculated emission factors for carbon monoxide,hydrocarbons,and nitrogen oxides from heavy-duty trucks in Islamabad were 12.94±1.46,15.21±1.67,and 10.69±1.34 g km^(-1)(95%confidence level),respectively,for pre-Pak-II trucks,and 12.75±2.80,14.24±3.53,and 10.24±2.34 g km^(-1)(95%confidence level),respectively,for Pak-II trucks,representing 2e20 times higher values than the emission standards in Pakistan and India.An altitude increase of approximately 4000 m,with the associated changes in meteorology and fleet characteristics,induced an average increase of 103.6%,86.3%,124.5%,and 133.6%in the emission factors of carbon monoxide,hydrocarbons,nitrogen oxides,and carbon dioxide,respectively.Moreover,on-road emissions along the CPEC were mainly influenced by truck types.This study will support the budget evaluation of transport emissions from the CPEC trade fleet.
文摘Hematite(α-Fe_(2)O_(3))constitutes one of the most promising photoanode materials for oxygen evolution reaction(OER).Recent research on Fe_(2)O_(3) have found a fast OER rate dependence on surface hole density,suggesting a multisite reaction pathway.However,the effect of heteroatom in Fe_(2)O_(3) on the multisite mechanism is still poorly understood.Herein we synthesized Fe_(2)O_(3) on Ti substrates(Fe_(2)O_(3)/Ti)to study the oxygen intermediates of OER by light-dark electrochemical scans.We identified the Fe-OH species disappeared and Ti-OH intermediates appeared on Fe_(2)O_(3)/Ti when pH=11‒14,which significantly improved the OER performance of Fe_(2)O_(3)/Ti.Combined with the density functional theory calculations,we propose that Ti atom acts as cocatalyst site and captures proton from neighboring Fe-OH species under highly alkaline condition,thereby promoting the coupling of Fe=O and reducing the energy barrier of the non-electrochemical step.Our work provides a new insight into the role of heteroatom in OER multisite mechanism based on clarifying the reaction intermediates.
基金supported by the National Natural Science Foundation of China (Nos. 41822505 , 42061130213 )the Royal Society-Newton Advanced Fellowship (No. NAF\R1\201166)+1 种基金Beijing Nova Program (No. Z181100006218077)the TsinghuaUniversity Initiative Scientific Research Program。
文摘Surface monitoring, vertical atmospheric column observation, and simulation using chemical transportation models are three dominant approaches for perception of fine particles with diameters less than 2.5 micrometers(PM2.5) concentration. Here we explored an imagebased methodology with a deep learning approach and machine learning approach to extend the ability on PM2.5 perception. Using 6976 images combined with daily weather conditions and hourly time data in Shanghai(2016), trained by hourly surface monitoring concentrations, an end-to-end model consisting of convolutional neural network and gradient boosting machine(GBM) was constructed. The mean absolute error, the root-mean-square error and the R-squared for PM2.5 concentration estimation using our proposed method is 3.56, 10.02, and 0.85 respectively. The transferability analysis showed that networks trained in Shanghai, fine-tuned with only 10% of images in other locations, achieved performances similar to ones from trained on data from target locations themselves. The sensitivity of different regions in the image to PM2.5 concentration was also quantified through the analysis of feature importance in GBM. All the required inputs in this study are commonly available, which greatly improved the accessibility of PM2.5 concentration for placed and period with no surface observation. And this study makes an exploratory attempt on pollution monitoring using graph theory and deep learning approach.
