Objective: To evaluate the role of prevention and control strategies for nosocomial infection in a tertiary teaching hospital during the sudden outbreak of Corona Virus Disease 2019 (COVID-19). Methods: The hospital i...Objective: To evaluate the role of prevention and control strategies for nosocomial infection in a tertiary teaching hospital during the sudden outbreak of Corona Virus Disease 2019 (COVID-19). Methods: The hospital initiated an emergency plan involving multi-departmental defense and control. It adopted a series of nosocomial infection prevention and control measures, including strengthening pre-examination and triage, optimizing the consultation process, improving the hospital’s architectural composition, implementing graded risk management, enhancing personal protection, and implementing staff training and supervision. Descriptive research was used to evaluate the short-term effects of these in-hospital prevention and control strategies. The analysis compared changes in related evaluation indicators between January 24, 2020 and February 12, 2020 (Chinese Lunar New Year’s Eve 2020 to lunar January 19) and the corresponding lunar period of the previous year. Results: Compared to the same period last year, the outpatient fever rate increased by 1.85-fold (P P Conclusion: The nosocomial infection prevention and control strategies implemented during this specific period improved the detection and control abilities for the COVID-19 source of infection and enhanced the compliance with measures. This likely contributed significantly to avoiding the occurrence of nosocomial infection.展开更多
The influence of Arctic sea ice concentration (SIC) on the subseasonal prediction of the North Atlantic Oscillation (NAO) event is investigated by utilizing the Community Atmospheric Model version 4. The optimal Arcti...The influence of Arctic sea ice concentration (SIC) on the subseasonal prediction of the North Atlantic Oscillation (NAO) event is investigated by utilizing the Community Atmospheric Model version 4. The optimal Arctic SIC perturbations which exert the greatest influence on the onset of an NAO event from a lead of three pentads (15 days) are obtained with a conditional nonlinear optimal perturbation approach. Numerical results show that there are two types of optimal Arctic SIC perturbations for each NAO event, with one weakening event (marked as type-1) and another strengthening event (marked as type-2). For positive NAO events, type-1 optimal SIC perturbations mainly show positive SIC anomalies in the Greenland, Barents, and Okhotsk Seas, while type-2 perturbations mainly feature negative SIC anomalies in these regions. For negative NAO events, the optimal SIC perturbations have almost opposite patterns to those in positive events, although there are some differences among these SIC perturbations due to different atmospheric initial conditions. Further diagnosis reveals that the optimal Arctic SIC perturbations first modify the surface turbulent heat flux and the temperature in the lower troposphere via diabatic processes. Afterward, the temperature in the low troposphere is mainly affected by dynamic advection. Finally, potential vorticity advection plays a crucial role in the 500-hPa geopotential height prediction in the northern North Atlantic sector during pentad 4, which influences NAO event prediction. These results highlight the importance of Arctic SIC on NAO event prediction and the spatial characteristics of the SIC perturbations may provide scientific support for target observations of SIC in improving NAO subseasonal predictions.展开更多
Utilizing the Community Atmosphere Model,version 4,the influence of Arctic sea-ice concentration(SIC)on the extended-range prediction of three simulated cold events(CEs)in East Asia is investigated.Numerical results s...Utilizing the Community Atmosphere Model,version 4,the influence of Arctic sea-ice concentration(SIC)on the extended-range prediction of three simulated cold events(CEs)in East Asia is investigated.Numerical results show that the Arctic SIC is crucial for the extended-range prediction of CEs in East Asia.The conditional nonlinear optimal perturbation approach is adopted to identify the optimal Arctic SIC perturbations with the largest influence on CE prediction on the extended-range time scale.It shows that the optimal SIC perturbations are more inclined to weaken the CEs and cause large prediction errors in the fourth pentad,as compared with random SIC perturbations under the same constraint.Further diagnosis reveals that the optimal SIC perturbations first modulate the local temperature through the diabatic process,and then influence the remote temperature by horizontal advection and vertical convection terms.Consequently,the optimal SIC perturbations trigger a warming center in East Asia through the propagation of Rossby wave trains,leading to the largest prediction uncertainty of the CEs in the fourth pentad.These results may provide scientific support for targeted observation of Arctic SIC to improve the extended-range CE prediction skill.展开更多
Three striking and impactful extreme cold weather events successively occurred across East Asia and North America during the mid-winter of 2020/21.These events open a new window to detect possible underlying physical ...Three striking and impactful extreme cold weather events successively occurred across East Asia and North America during the mid-winter of 2020/21.These events open a new window to detect possible underlying physical processes.The analysis here indicates that the occurrences of the three events resulted from integrated effects of a concurrence of anomalous thermal conditions in three oceans and interactive Arctic-lower latitude atmospheric circulation processes,which were linked and influenced by one major sudden stratospheric warming(SSW).The North Atlantic warm blob initiated an increased poleward transient eddy heat flux,reducing the Barents-Kara seas sea ice over a warmed ocean and disrupting the stratospheric polar vortex(SPV)to induce the major SSW.The Rossby wave trains excited by the North Atlantic warm blob and the tropical Pacific La Nina interacted with the Arctic tropospheric circulation anomalies or the tropospheric polar vortex to provide dynamic settings,steering cold polar air outbreaks.The long memory of the retreated sea ice with the underlying warm ocean and the amplified tropospheric blocking highs from the midlatitudes to the Arctic intermittently fueled the increased transient eddy heat flux to sustain the SSW over a long time period.The displaced or split SPV centers associated with the SSW played crucial roles in substantially intensifying the tropospheric circulation anomalies and moving the jet stream to the far south to cause cold air outbreaks to a rarely observed extreme state.The results have significant implications for increasing prediction skill and improving policy decision making to enhance resilience in“One Health,One Future”.展开更多
Three extreme cold events invaded China during the early winter period between December 2020 to mid-January 2021 and caused drastic temperature drops,setting new low-temperature records at many stations during 6−8 Jan...Three extreme cold events invaded China during the early winter period between December 2020 to mid-January 2021 and caused drastic temperature drops,setting new low-temperature records at many stations during 6−8 January 2021.These cold events occurred under background conditions of low Arctic sea ice extent and a La Niña event.This is somewhat expected since the coupled effect of large Arctic sea ice loss in autumn and sea surface temperature cooling in the tropical Pacific usually favors cold event occurrences in Eurasia.Further diagnosis reveals that the first cold event is related to the southward movement of the polar vortex and the second one is related to a continent-wide ridge,while both the southward polar vortex and the Asian blocking are crucial for the third event.Here,we evaluate the forecast skill for these three events utilizing the operational forecasts from the ECMWF model.We find that the third event had the highest predictability since it achieves the best skill in forecasting the East Asian cooling among the three events.Therefore,the predictability of these cold events,as well as their relationships with the atmospheric initial conditions,Arctic sea ice,and La Niña deserve further investigation.展开更多
This study focuses on the climatic impacts of the Atlantic Multidecadal Oscillation(AMO) as a mode of internal variability. Given the difficulties involved in excluding the effects of external forcing from internal va...This study focuses on the climatic impacts of the Atlantic Multidecadal Oscillation(AMO) as a mode of internal variability. Given the difficulties involved in excluding the effects of external forcing from internal variation, i.e., owing to the short record length of instrumental observations and historical simulations, we assess and compare the AMO and its related climatic impacts both in observations and in the "Pre-industrial" experiments of models participating in CMIP5. First, we evaluate the skill of the 25 CMIP5 models' "Historical" simulations in simulating the observational AMO, and find there is generally a considerable range of skill among them in this regard. Six of the models with higher skill relative to the other models are selected to investigate the AMO-related climate impacts, and it is found that their "Pre-industrial" simulations capture the essential features of the AMO. A positive AMO favors warmer surface temperature around the North Atlantic,and the Atlantic ITCZ shifts northward leading to more rainfall in the Sahel and less rainfall in Brazil. Furthermore, the results confirm the existence of a teleconnection between the AMO and East Asian surface temperature, as well as the late withdrawal of the Indian summer monsoon, during positive AMO phases. These connections could be mainly caused by internal climate variability. Opposite patterns are true for the negative phase of the AMO.展开更多
The role of winter sea-ice in the Labrador Sea as a precursor for precipitation anomalies over southeastern North America and Western Europe in the following spring is investigated. In general terms, as the sea ice in...The role of winter sea-ice in the Labrador Sea as a precursor for precipitation anomalies over southeastern North America and Western Europe in the following spring is investigated. In general terms, as the sea ice increases, the precipitation also increases. In more detail, however, analyses indicate that both the winter sea-ice and the sea surface temperature(SST)anomalies related to increases in winter sea-ice in the Labrador Sea can persist into the following spring. These features play a forcing role in the spring atmosphere, which may be the physical mechanism behind the observational relationship between the winter sea-ice and spring precipitation anomalies. The oceanic forcings in spring include Arctic sea-ice anomalies and SST anomalies in the tropical Pacific and high-latitude North Atlantic. Multi-model Coupled Model Intercomparison Project Phase 5 and Atmospheric Model Intercomparison Project simulation results show that the atmospheric circulation response to the combination of sea-ice and SST is similar to that observed, which suggests that the oceanic forcings are indeed the physical reason for the enhanced spring precipitation. Sensitivity experiments conducted using an atmospheric general circulation model indicate that the increases in precipitation over southeastern North America are mainly attributable to the effect of the SST anomalies, while the increases over Western Europe are mainly due to the sea-ice anomalies. Although model simulations reveal that the SST anomalies play the primary role in the precipitation anomalies over southeastern North America, the observational statistical analyses indicate that the area of sea-ice in the Labrador Sea seems to be the precursor that best predicts the spring precipitation anomaly.展开更多
This study compares the impacts of interannual Arctic sea ice loss and ENSO events on winter haze days in China's Mainland through observational analyses and AGCM sensitivity experiments. The results suggest that(...This study compares the impacts of interannual Arctic sea ice loss and ENSO events on winter haze days in China's Mainland through observational analyses and AGCM sensitivity experiments. The results suggest that(1) Arctic sea ice loss favors an increase in haze days in central–eastern China;(2) the impact of ENSO is overall contained within southern China, with increased(reduced) haze days during La Ni?a(El Ni?o) winters; and(3) the impacts from sea ice loss and ENSO are linearly additive. Mechanistically, Arctic sea ice loss causes quasi-barotropic positive height anomalies over the region from northern Europe to the Ural Mountains(Urals in brief) and weak and negative height anomalies over the region from central Asia to northeastern Asia. The former favors intensified frequency of the blocking over the regions from northern Europe to the Urals, whereas the latter favors an even air pressure distribution over Siberia, Mongolia, and East Asia. This large-scale circulation pattern favors more frequent occurrence of calm and steady weather in northern China and, as a consequence, increased occurrence of haze days. In comparison,La Ni?a(El Ni?o) exerts its influence along a tropical pathway by inducing a cyclonic(anticyclonic) lower-tropospheric atmospheric circulation response over the subtropical northwestern Pacific. The northeasterly(southwesterly)anomaly at the northwestern rear of the cyclone(anticyclone) causes reduced(intensified) rainfall over southeastern China, which favors increased(reduced) occurrence of haze days through the rain-washing effect.展开更多
Drosophila has been extensively used to model the human blood-immune system,as both systems share many developmental and immune response mechanisms.However,while many human blood cell types have been identified,only t...Drosophila has been extensively used to model the human blood-immune system,as both systems share many developmental and immune response mechanisms.However,while many human blood cell types have been identified,only three were found in flies:plasmatocytes,crystal cells and lamellocytes.To better understand the complexity of fly blood system,we used single-cell RNA sequencing technology to generate co mprehensive gene expression profiles for Drosophila circulating blood cells.In addition to the known cell types,we identified two new Drosophila blood cell types:thanacytes and primocytes.Thanacytes,which express many stimulus response genes,are involved in distinct responses to different types of bacteria.Primocytes,which express cell fate commitment and signaling genes,appear to be involved in keeping stem cells in the circulating blood.Furthermore,our data revealed four novel plasmatocyte subtypes(Ppn+,CAH7^+,Lsp^+and reservoir plasmatocytes),each with unique molecular identities and distinct predicted functions.We also identified cross-species markers from Drosophila hemocytes to human blood cells.Our analysis unveiled a more complex Drosophila blood system and broadened the scope of using Drosophila to model human blood system in development and disease.展开更多
Background:To describe the epidemiological characteristics of central nervous system(CNS)tumors in children,based on the neurosurgery department of Beijing Tiantan Hospital.Methods:From January 2015 to December 2019,3...Background:To describe the epidemiological characteristics of central nervous system(CNS)tumors in children,based on the neurosurgery department of Beijing Tiantan Hospital.Methods:From January 2015 to December 2019,3180 children were histopathologically diagnosed with CNS tumors based on the 2016 World Health Organization(WHO)classification of tumors.Patients were 0 to 15 years old.We analyzed age-related gender preferences,tumor locations,and the histological grades of the tumors.In addition,the epidemiological characteristics of the five most common intracranial tumors were compared to the previous studies.Results:In this study,intracranial and spinal tumors account for 96.4%(3066)and 3.6%(114)of all tumors,with a preponderance of supratentorial tumors(57.9%).Among all pediatric patients,low-grade tumors comprise 67.1%(2135).The integral gender ratio of males to females is 1.47:1 and the average age of patients is 7.59 years old.The five most common intracranial tumors are craniopharyngioma(15.4%),medulloblastoma(14.3%),pilocytic astrocytoma(11.8%),diffuse astrocytoma(9.8%),and anaplastic ependymoma(4.8%).Conclusions:Due to the lack of national data on childhood brain tumors,we used a large nationally representative population sample based on the largest pediatric neurosurgery center in China.We analyzed the data of the past 5 years,reflecting the incidence of CNS tumors in Chinese children to a certain extent,and laying a data foundation for subsequent clinical studies.展开更多
文摘Objective: To evaluate the role of prevention and control strategies for nosocomial infection in a tertiary teaching hospital during the sudden outbreak of Corona Virus Disease 2019 (COVID-19). Methods: The hospital initiated an emergency plan involving multi-departmental defense and control. It adopted a series of nosocomial infection prevention and control measures, including strengthening pre-examination and triage, optimizing the consultation process, improving the hospital’s architectural composition, implementing graded risk management, enhancing personal protection, and implementing staff training and supervision. Descriptive research was used to evaluate the short-term effects of these in-hospital prevention and control strategies. The analysis compared changes in related evaluation indicators between January 24, 2020 and February 12, 2020 (Chinese Lunar New Year’s Eve 2020 to lunar January 19) and the corresponding lunar period of the previous year. Results: Compared to the same period last year, the outpatient fever rate increased by 1.85-fold (P P Conclusion: The nosocomial infection prevention and control strategies implemented during this specific period improved the detection and control abilities for the COVID-19 source of infection and enhanced the compliance with measures. This likely contributed significantly to avoiding the occurrence of nosocomial infection.
基金the National Natural Science Foundation of China(Grant Nos.42288101,41790475,42005046,and 41775001).
文摘The influence of Arctic sea ice concentration (SIC) on the subseasonal prediction of the North Atlantic Oscillation (NAO) event is investigated by utilizing the Community Atmospheric Model version 4. The optimal Arctic SIC perturbations which exert the greatest influence on the onset of an NAO event from a lead of three pentads (15 days) are obtained with a conditional nonlinear optimal perturbation approach. Numerical results show that there are two types of optimal Arctic SIC perturbations for each NAO event, with one weakening event (marked as type-1) and another strengthening event (marked as type-2). For positive NAO events, type-1 optimal SIC perturbations mainly show positive SIC anomalies in the Greenland, Barents, and Okhotsk Seas, while type-2 perturbations mainly feature negative SIC anomalies in these regions. For negative NAO events, the optimal SIC perturbations have almost opposite patterns to those in positive events, although there are some differences among these SIC perturbations due to different atmospheric initial conditions. Further diagnosis reveals that the optimal Arctic SIC perturbations first modify the surface turbulent heat flux and the temperature in the lower troposphere via diabatic processes. Afterward, the temperature in the low troposphere is mainly affected by dynamic advection. Finally, potential vorticity advection plays a crucial role in the 500-hPa geopotential height prediction in the northern North Atlantic sector during pentad 4, which influences NAO event prediction. These results highlight the importance of Arctic SIC on NAO event prediction and the spatial characteristics of the SIC perturbations may provide scientific support for target observations of SIC in improving NAO subseasonal predictions.
基金the National Natural Science Foundation of China(Grant Nos.42288101,41790475,42175051,and 42005046)the State Key Laboratory of Tropical Oceanography(South China Sea Institute of Oceanology,Chinese Academy of Sciences+1 种基金Grant No.LTO2109)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021A1515011868).
文摘Utilizing the Community Atmosphere Model,version 4,the influence of Arctic sea-ice concentration(SIC)on the extended-range prediction of three simulated cold events(CEs)in East Asia is investigated.Numerical results show that the Arctic SIC is crucial for the extended-range prediction of CEs in East Asia.The conditional nonlinear optimal perturbation approach is adopted to identify the optimal Arctic SIC perturbations with the largest influence on CE prediction on the extended-range time scale.It shows that the optimal SIC perturbations are more inclined to weaken the CEs and cause large prediction errors in the fourth pentad,as compared with random SIC perturbations under the same constraint.Further diagnosis reveals that the optimal SIC perturbations first modulate the local temperature through the diabatic process,and then influence the remote temperature by horizontal advection and vertical convection terms.Consequently,the optimal SIC perturbations trigger a warming center in East Asia through the propagation of Rossby wave trains,leading to the largest prediction uncertainty of the CEs in the fourth pentad.These results may provide scientific support for targeted observation of Arctic SIC to improve the extended-range CE prediction skill.
基金supported by the U.S. Department of Energy (Grant No. DE-SC0020640)the National Natural Science Foundation of China (Grant Nos. 41675041 and 41790475)+6 种基金the Arctic Research Program of the NOAA Global Ocean Monitoring and Observing Officethe Deutsche Forschungsgemeinschaft (project 268020496 TRR 172 within the Transregional Collaborative Research Center “Arcti C Amplification:Climate Relevant Atmospheric and Surfa Ce Processesand Feedback Mechanisms (AC)3”)the Academy of Finland (contract 317999)the Cooperative Institute for ClimateOcean&Ecosystem Studies (CIOCES) under NOAA Cooperative Agreement NA20OAR4320271.
文摘Three striking and impactful extreme cold weather events successively occurred across East Asia and North America during the mid-winter of 2020/21.These events open a new window to detect possible underlying physical processes.The analysis here indicates that the occurrences of the three events resulted from integrated effects of a concurrence of anomalous thermal conditions in three oceans and interactive Arctic-lower latitude atmospheric circulation processes,which were linked and influenced by one major sudden stratospheric warming(SSW).The North Atlantic warm blob initiated an increased poleward transient eddy heat flux,reducing the Barents-Kara seas sea ice over a warmed ocean and disrupting the stratospheric polar vortex(SPV)to induce the major SSW.The Rossby wave trains excited by the North Atlantic warm blob and the tropical Pacific La Nina interacted with the Arctic tropospheric circulation anomalies or the tropospheric polar vortex to provide dynamic settings,steering cold polar air outbreaks.The long memory of the retreated sea ice with the underlying warm ocean and the amplified tropospheric blocking highs from the midlatitudes to the Arctic intermittently fueled the increased transient eddy heat flux to sustain the SSW over a long time period.The displaced or split SPV centers associated with the SSW played crucial roles in substantially intensifying the tropospheric circulation anomalies and moving the jet stream to the far south to cause cold air outbreaks to a rarely observed extreme state.The results have significant implications for increasing prediction skill and improving policy decision making to enhance resilience in“One Health,One Future”.
基金support from the National Natural Science Foundation of China(Grant Nos:41790475,42005046,and 41790473)。
文摘Three extreme cold events invaded China during the early winter period between December 2020 to mid-January 2021 and caused drastic temperature drops,setting new low-temperature records at many stations during 6−8 January 2021.These cold events occurred under background conditions of low Arctic sea ice extent and a La Niña event.This is somewhat expected since the coupled effect of large Arctic sea ice loss in autumn and sea surface temperature cooling in the tropical Pacific usually favors cold event occurrences in Eurasia.Further diagnosis reveals that the first cold event is related to the southward movement of the polar vortex and the second one is related to a continent-wide ridge,while both the southward polar vortex and the Asian blocking are crucial for the third event.Here,we evaluate the forecast skill for these three events utilizing the operational forecasts from the ECMWF model.We find that the third event had the highest predictability since it achieves the best skill in forecasting the East Asian cooling among the three events.Therefore,the predictability of these cold events,as well as their relationships with the atmospheric initial conditions,Arctic sea ice,and La Niña deserve further investigation.
基金jointly supported by the National Natural Science Foundation of China(Grant No.41421004)the National Key Basic Research Development Program of China(Grant No.2016YFA0601802 and 2015CB453202)the National Natural Science Foundation of China(Grant Nos.41375085)
文摘This study focuses on the climatic impacts of the Atlantic Multidecadal Oscillation(AMO) as a mode of internal variability. Given the difficulties involved in excluding the effects of external forcing from internal variation, i.e., owing to the short record length of instrumental observations and historical simulations, we assess and compare the AMO and its related climatic impacts both in observations and in the "Pre-industrial" experiments of models participating in CMIP5. First, we evaluate the skill of the 25 CMIP5 models' "Historical" simulations in simulating the observational AMO, and find there is generally a considerable range of skill among them in this regard. Six of the models with higher skill relative to the other models are selected to investigate the AMO-related climate impacts, and it is found that their "Pre-industrial" simulations capture the essential features of the AMO. A positive AMO favors warmer surface temperature around the North Atlantic,and the Atlantic ITCZ shifts northward leading to more rainfall in the Sahel and less rainfall in Brazil. Furthermore, the results confirm the existence of a teleconnection between the AMO and East Asian surface temperature, as well as the late withdrawal of the Indian summer monsoon, during positive AMO phases. These connections could be mainly caused by internal climate variability. Opposite patterns are true for the negative phase of the AMO.
基金supported by the Natural Science Foundation of China (Grant Nos.41305064 and 41375085)a strategic project of the Chinese Academy of Sciences (Grant No.XDA11010401)the China Scholarship Council
文摘The role of winter sea-ice in the Labrador Sea as a precursor for precipitation anomalies over southeastern North America and Western Europe in the following spring is investigated. In general terms, as the sea ice increases, the precipitation also increases. In more detail, however, analyses indicate that both the winter sea-ice and the sea surface temperature(SST)anomalies related to increases in winter sea-ice in the Labrador Sea can persist into the following spring. These features play a forcing role in the spring atmosphere, which may be the physical mechanism behind the observational relationship between the winter sea-ice and spring precipitation anomalies. The oceanic forcings in spring include Arctic sea-ice anomalies and SST anomalies in the tropical Pacific and high-latitude North Atlantic. Multi-model Coupled Model Intercomparison Project Phase 5 and Atmospheric Model Intercomparison Project simulation results show that the atmospheric circulation response to the combination of sea-ice and SST is similar to that observed, which suggests that the oceanic forcings are indeed the physical reason for the enhanced spring precipitation. Sensitivity experiments conducted using an atmospheric general circulation model indicate that the increases in precipitation over southeastern North America are mainly attributable to the effect of the SST anomalies, while the increases over Western Europe are mainly due to the sea-ice anomalies. Although model simulations reveal that the SST anomalies play the primary role in the precipitation anomalies over southeastern North America, the observational statistical analyses indicate that the area of sea-ice in the Labrador Sea seems to be the precursor that best predicts the spring precipitation anomaly.
基金jointly supported by the National Natural Science Foundation of China [grant numbers 41790473 and41421004]the Strategic Priority Research Program of the Chinese Academy of Sciences [grant number XDA19070402]
基金Supported by the Strategic Project of the Chinese Academy of Sciences(XDA11010401)China Meteorological Administration Special Public Welfare Research Fund(GYHY201306026)National(Key) Basic Research and Development(973)Program of China(2015CB453202 and 2016YFA0601802)
文摘This study compares the impacts of interannual Arctic sea ice loss and ENSO events on winter haze days in China's Mainland through observational analyses and AGCM sensitivity experiments. The results suggest that(1) Arctic sea ice loss favors an increase in haze days in central–eastern China;(2) the impact of ENSO is overall contained within southern China, with increased(reduced) haze days during La Ni?a(El Ni?o) winters; and(3) the impacts from sea ice loss and ENSO are linearly additive. Mechanistically, Arctic sea ice loss causes quasi-barotropic positive height anomalies over the region from northern Europe to the Ural Mountains(Urals in brief) and weak and negative height anomalies over the region from central Asia to northeastern Asia. The former favors intensified frequency of the blocking over the regions from northern Europe to the Urals, whereas the latter favors an even air pressure distribution over Siberia, Mongolia, and East Asia. This large-scale circulation pattern favors more frequent occurrence of calm and steady weather in northern China and, as a consequence, increased occurrence of haze days. In comparison,La Ni?a(El Ni?o) exerts its influence along a tropical pathway by inducing a cyclonic(anticyclonic) lower-tropospheric atmospheric circulation response over the subtropical northwestern Pacific. The northeasterly(southwesterly)anomaly at the northwestern rear of the cyclone(anticyclone) causes reduced(intensified) rainfall over southeastern China, which favors increased(reduced) occurrence of haze days through the rain-washing effect.
基金supported by grants from NIH to Z.H.(R01-HL134940,R01-DK098410)。
文摘Drosophila has been extensively used to model the human blood-immune system,as both systems share many developmental and immune response mechanisms.However,while many human blood cell types have been identified,only three were found in flies:plasmatocytes,crystal cells and lamellocytes.To better understand the complexity of fly blood system,we used single-cell RNA sequencing technology to generate co mprehensive gene expression profiles for Drosophila circulating blood cells.In addition to the known cell types,we identified two new Drosophila blood cell types:thanacytes and primocytes.Thanacytes,which express many stimulus response genes,are involved in distinct responses to different types of bacteria.Primocytes,which express cell fate commitment and signaling genes,appear to be involved in keeping stem cells in the circulating blood.Furthermore,our data revealed four novel plasmatocyte subtypes(Ppn+,CAH7^+,Lsp^+and reservoir plasmatocytes),each with unique molecular identities and distinct predicted functions.We also identified cross-species markers from Drosophila hemocytes to human blood cells.Our analysis unveiled a more complex Drosophila blood system and broadened the scope of using Drosophila to model human blood system in development and disease.
文摘Background:To describe the epidemiological characteristics of central nervous system(CNS)tumors in children,based on the neurosurgery department of Beijing Tiantan Hospital.Methods:From January 2015 to December 2019,3180 children were histopathologically diagnosed with CNS tumors based on the 2016 World Health Organization(WHO)classification of tumors.Patients were 0 to 15 years old.We analyzed age-related gender preferences,tumor locations,and the histological grades of the tumors.In addition,the epidemiological characteristics of the five most common intracranial tumors were compared to the previous studies.Results:In this study,intracranial and spinal tumors account for 96.4%(3066)and 3.6%(114)of all tumors,with a preponderance of supratentorial tumors(57.9%).Among all pediatric patients,low-grade tumors comprise 67.1%(2135).The integral gender ratio of males to females is 1.47:1 and the average age of patients is 7.59 years old.The five most common intracranial tumors are craniopharyngioma(15.4%),medulloblastoma(14.3%),pilocytic astrocytoma(11.8%),diffuse astrocytoma(9.8%),and anaplastic ependymoma(4.8%).Conclusions:Due to the lack of national data on childhood brain tumors,we used a large nationally representative population sample based on the largest pediatric neurosurgery center in China.We analyzed the data of the past 5 years,reflecting the incidence of CNS tumors in Chinese children to a certain extent,and laying a data foundation for subsequent clinical studies.
