Episodes of fine-particulate matter(PM_(2.5))pollution are a widespread and common occurrence in China,and have potentially serious implications for human health.Meteorological conditions play an important role in air...Episodes of fine-particulate matter(PM_(2.5))pollution are a widespread and common occurrence in China,and have potentially serious implications for human health.Meteorological conditions play an important role in air quality and influence the formation of regional air pollution episodes.This study applied a new classification method and daily PM_(2.5)concentration data to(a)evaluate different levels of air pollution in the Sichuan-Chongqing region between 2015 and 2017,and(b)investigate their relationships with meteorological parameters including atmospheric boundary layer height,wind speed,temperature inversion,weather type,and atmospheric transport.We identified a total of 40 air pollution episodes,the most severe of which occurred in winter when the atmospheric layer height was low.These heavy pollution events also coincided with low surface(10 m)wind speeds and temperature inversions,weather conditions that generally result from low pressure over the northwestern Sichuan Basin(90-102°E,28-36°N)and southerly atmospheric transport.展开更多
The Asian Tropopause Aerosols Layer(ATAL)refers to an accumulation of aerosols in the upper troposphere and lower stratosphere during boreal summer over Asia,which has a fundamental impact on the monsoon system and cl...The Asian Tropopause Aerosols Layer(ATAL)refers to an accumulation of aerosols in the upper troposphere and lower stratosphere during boreal summer over Asia,which has a fundamental impact on the monsoon system and climate change.In this study,we primarily analyze the seasonal to sub-seasonal variations of the ATAL and the factors potentially influencing those variations based on MERRA2 reanalysis.The ability of the reanalysis to reproduce the ATAL is well validated by CALIPSO observations from May to October 2016.The results reveal that the ATAL has a synchronous spatiotemporal pattern with the development and movement of the Asian Summer Monsoon.Significant enhancement of ATAL intensity is found during the prevailing monsoon period of July-August,with two maxima centered over South Asia and the Arabian Peninsula.Owing to the fluctuations of deep convection,the ATAL shows an episodic variation on a timescale of 7-12 days.Attribution analysis indicates that deep convection dominates the variability of the ATAL with a contribution of 62.7%,followed by a contribution of 36.6%from surface pollutants.The impact of precipitation is limited.The ATAL further shows a clear diurnal variation:the peak of ATAL intensity occurs from 17:30 to 23:30 local time(LT),when the deep convection becomes strongest;the minimum ATAL intensity occurs around 8:30 LT owing to the weakened deep convection and photochemical reactions in clouds.The aerosol components of the ATAL show different spatiotemporal patterns and imply that black carbon and organic carbon come mainly from India,whereas sulfate comes mainly from China during the prevailing monsoon period.展开更多
Background Early evaluation of prognosis in cardiogenic shock(CS)is crucial for tailored treatment selection.Both lactate clearance and lactate levels are considered useful prognostic biomarkers in patients with CS.Ho...Background Early evaluation of prognosis in cardiogenic shock(CS)is crucial for tailored treatment selection.Both lactate clearance and lactate levels are considered useful prognostic biomarkers in patients with CS.However,there is yet no literature comparing the 6-hour lactate clearance rate(Δ6Lac)with lactate levels measured at admission(L1)and after 6 h(L2)to predict 30-day mortality in CS.Methods In this observational cohort study,95 patients with CS were treated at Department of Intensive Care Unit,Yiwu Central Hospital between January 2020 and December 2022.Of these,88 patients met the eligibility criteria.The lactate levels were measured after admission(L1)as the baseline lactate value,and were measured after 6 h(L2)following admission.The primary endpoint of the study was survival rate at 30 days.A receiver operating characteristic curve was used for data analysis.Univariate and multivariate Cox regression analyses were performed based onΔ6Lac.Kaplan–Meier(KM)survival curves were generated to compare the 30-day survival rates among L1,L2,andΔ6Lac.Results TheΔ6Lac model showed the highest area under the curve value(0.839),followed by the L2(0.805)and L1(0.668)models.TheΔ6Lac model showed a sensitivity of 84.2%and specificity of 75.4%.The L1 and L2 models had sensitivities of 57.9%each and specificities of 89.9%and 98.6%,respectively.The cut-off values forΔ6Lac,L1,and L2 were 18.2%,6.7 mmol/L,and 6.1 mmol/L,respectively.Univariate Cox regression analysis revealed a significant association betweenΔ6Lac and 30-day mortality.After adjusting for five models in multivariate Cox regression,Δ6Lac remained a significant risk factor for 30-day mortality in patients with CS.In our fifth multivariate Cox regression model,Δ6Lac remained a risk factor associated with 30-day mortality(hazard ratio[HR]=5.14,95%confidence interval[CI]:1.48 to 17.89,P=0.010)as well as L2(HR=8.42,95%CI:1.26 to 56.22,P=0.028).The KM survival curve analysis revealed that L1>6.7 mmol/L(HR=8.08,95%CI:3.23 to 20.20,P<0.001),L2>6.1 mmol/L(HR=25.97,95%CI:9.76 to 69.15,P<0.001),andΔ6Lac≤18.2%(HR=8.92,95%CI:2.95 to 26.95,P<0.001)were associated with a higher risk of 30-day mortality.ConclusionsΔ6Lac is a better predictor for 30-day mortality in CS than lactate levels at admission.It has a predictive value equivalent to that of lactate level at 6 h after admission,making it an important surrogate indicator for evaluating the suitability as well as poor prognosis after CS treatment.We found that a cut-off value of 18.2%forΔ6Lac provided the most accurate assessment of early prognosis in CS.展开更多
基金supported by the Innovative Research Groups of the National Natural Science Foundation of China(No.41521004)the National Natural Science Foundation of China(Nos.41875091 and 51979042)the Lanzhou City’s scientific research funding subsidy to Lanzhou University
文摘Episodes of fine-particulate matter(PM_(2.5))pollution are a widespread and common occurrence in China,and have potentially serious implications for human health.Meteorological conditions play an important role in air quality and influence the formation of regional air pollution episodes.This study applied a new classification method and daily PM_(2.5)concentration data to(a)evaluate different levels of air pollution in the Sichuan-Chongqing region between 2015 and 2017,and(b)investigate their relationships with meteorological parameters including atmospheric boundary layer height,wind speed,temperature inversion,weather type,and atmospheric transport.We identified a total of 40 air pollution episodes,the most severe of which occurred in winter when the atmospheric layer height was low.These heavy pollution events also coincided with low surface(10 m)wind speeds and temperature inversions,weather conditions that generally result from low pressure over the northwestern Sichuan Basin(90-102°E,28-36°N)and southerly atmospheric transport.
基金supported by the National Key Research and Development Program of China(No.2019YFA0606801)the Innovative Research Groups of the National Natural Science Foundation of China(No.41521004)+2 种基金the National Natural Science Foundation of China(No.41875091)the China Postdoctoral Science Foundation(No.2020M673530)the Supercomputing Center of Lanzhou University
文摘The Asian Tropopause Aerosols Layer(ATAL)refers to an accumulation of aerosols in the upper troposphere and lower stratosphere during boreal summer over Asia,which has a fundamental impact on the monsoon system and climate change.In this study,we primarily analyze the seasonal to sub-seasonal variations of the ATAL and the factors potentially influencing those variations based on MERRA2 reanalysis.The ability of the reanalysis to reproduce the ATAL is well validated by CALIPSO observations from May to October 2016.The results reveal that the ATAL has a synchronous spatiotemporal pattern with the development and movement of the Asian Summer Monsoon.Significant enhancement of ATAL intensity is found during the prevailing monsoon period of July-August,with two maxima centered over South Asia and the Arabian Peninsula.Owing to the fluctuations of deep convection,the ATAL shows an episodic variation on a timescale of 7-12 days.Attribution analysis indicates that deep convection dominates the variability of the ATAL with a contribution of 62.7%,followed by a contribution of 36.6%from surface pollutants.The impact of precipitation is limited.The ATAL further shows a clear diurnal variation:the peak of ATAL intensity occurs from 17:30 to 23:30 local time(LT),when the deep convection becomes strongest;the minimum ATAL intensity occurs around 8:30 LT owing to the weakened deep convection and photochemical reactions in clouds.The aerosol components of the ATAL show different spatiotemporal patterns and imply that black carbon and organic carbon come mainly from India,whereas sulfate comes mainly from China during the prevailing monsoon period.
基金supported by the Major(Key)Science and Technology Research Project of Jinhua(Grant No.2021-3-019).
文摘Background Early evaluation of prognosis in cardiogenic shock(CS)is crucial for tailored treatment selection.Both lactate clearance and lactate levels are considered useful prognostic biomarkers in patients with CS.However,there is yet no literature comparing the 6-hour lactate clearance rate(Δ6Lac)with lactate levels measured at admission(L1)and after 6 h(L2)to predict 30-day mortality in CS.Methods In this observational cohort study,95 patients with CS were treated at Department of Intensive Care Unit,Yiwu Central Hospital between January 2020 and December 2022.Of these,88 patients met the eligibility criteria.The lactate levels were measured after admission(L1)as the baseline lactate value,and were measured after 6 h(L2)following admission.The primary endpoint of the study was survival rate at 30 days.A receiver operating characteristic curve was used for data analysis.Univariate and multivariate Cox regression analyses were performed based onΔ6Lac.Kaplan–Meier(KM)survival curves were generated to compare the 30-day survival rates among L1,L2,andΔ6Lac.Results TheΔ6Lac model showed the highest area under the curve value(0.839),followed by the L2(0.805)and L1(0.668)models.TheΔ6Lac model showed a sensitivity of 84.2%and specificity of 75.4%.The L1 and L2 models had sensitivities of 57.9%each and specificities of 89.9%and 98.6%,respectively.The cut-off values forΔ6Lac,L1,and L2 were 18.2%,6.7 mmol/L,and 6.1 mmol/L,respectively.Univariate Cox regression analysis revealed a significant association betweenΔ6Lac and 30-day mortality.After adjusting for five models in multivariate Cox regression,Δ6Lac remained a significant risk factor for 30-day mortality in patients with CS.In our fifth multivariate Cox regression model,Δ6Lac remained a risk factor associated with 30-day mortality(hazard ratio[HR]=5.14,95%confidence interval[CI]:1.48 to 17.89,P=0.010)as well as L2(HR=8.42,95%CI:1.26 to 56.22,P=0.028).The KM survival curve analysis revealed that L1>6.7 mmol/L(HR=8.08,95%CI:3.23 to 20.20,P<0.001),L2>6.1 mmol/L(HR=25.97,95%CI:9.76 to 69.15,P<0.001),andΔ6Lac≤18.2%(HR=8.92,95%CI:2.95 to 26.95,P<0.001)were associated with a higher risk of 30-day mortality.ConclusionsΔ6Lac is a better predictor for 30-day mortality in CS than lactate levels at admission.It has a predictive value equivalent to that of lactate level at 6 h after admission,making it an important surrogate indicator for evaluating the suitability as well as poor prognosis after CS treatment.We found that a cut-off value of 18.2%forΔ6Lac provided the most accurate assessment of early prognosis in CS.
