Mainly for the problem that the friction force generated by the existing process of bind-ing,fixing and fastening the flexible cable on the satellite is unknown,the friction force analysis and experimental research on...Mainly for the problem that the friction force generated by the existing process of bind-ing,fixing and fastening the flexible cable on the satellite is unknown,the friction force analysis and experimental research on the binding point of the flexible cable are carried out.The equivalent model of the cable bundle bound by nylon cable ties is established,the force on the binding point is analyzed,and the empirical formula for calculating the friction force at the binding point is estab-lished.The formula shows that the friction force is related to the cable bundle diameter,the number of winding cycles of silicone rubber tape,the width of nylon cable ties,and the binding force.The friction force tests of the cable diameter of 5.06 mm,8.02 mm,24.02 mm,38.04 mm under different winding turns of tape were carried out,which was compared with the theoretical calculation value.It is concluded that the calculation accuracy of the theoretical model is more than 95%,which can estimate the actual friction force value accurately.This provides a reference and basis for the theoretical and experimental research on the friction force of the flexible cable binding point on satellite.展开更多
Apatite fission track(AFT)analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain,northwest China.AFT ages range from 136.2 to 85.6 Ma and are younger than ...Apatite fission track(AFT)analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain,northwest China.AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths(11.0e13.2 mm)mostly showing unimodal distribution are shorten,indicating significant track-annealing.Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassiceearly Cretaceous and the OligoceneeMiocene.Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas.The fission-track ages of the southwest area are relatively older(>100 Ma),recording the earlier rapid uplift phase during the late JurassiceCretaceous,while the ages in the north piedmont of the Bogda Mountain(namely the northeast part)are younger(<60 Ma),mainly reflecting the later rapid uplift phase in the OligoceneeMiocene.The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest.In the thrust fault-dominated northern limbs of the Bogda Mountain,AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones,showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic.The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic,respectively.展开更多
Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The disease is caused by Candidatus Liberibacter spp., which is vectored by the psyllids Diaphorina citri Kuwayama and Trioza erytreae. Secretor...Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The disease is caused by Candidatus Liberibacter spp., which is vectored by the psyllids Diaphorina citri Kuwayama and Trioza erytreae. Secretory proteins are important in bacterial pathogenesis and structure components. Some of them are expressed at a high level. To obtain the highly-expressed secretory protein genes (SPGs) for antiserum preparation, six candidate SPGs were chosen from Candidatus Liberibacter asiaticus by bioinformatic analysis and were further tested by qPCR and RT-qPCR methods, respectively. The result showed that two SPGs, 408 and pap (both are Flp pilus assembly protein genes), have relative high amounts of DNA and RNA transcripts of early HLB-infected green orange leaves. The 408 and pap genes were further constructed into the plant expression vector pCAMBIA1300 (GV1300: GFP) and expressed in tobacco leaf epidermal cells for subcellular localization analysis. The transient expression results indicated that the 408 protein is located in the nuclei and cytoplasm of tobacco leaf cells. However, the pap protein is located in the cytoplasm of tobacco leaf cells, which may help the pathogen invade into plant cells. This research is an important foundation for the preparation of the antiserum against Candidatus Liberibacter asiaticus and the early detection of HLB disease.展开更多
Despite the widespread assumption that outdoor environments provide sufficient ventilation and dilution capacity to mitigate the risk of COVID-19 infection,there is little understanding of airborne infection risk in o...Despite the widespread assumption that outdoor environments provide sufficient ventilation and dilution capacity to mitigate the risk of COVID-19 infection,there is little understanding of airborne infection risk in outdoor urban areas with poor ventilation.To address this gap,we propose a modified Wells-Riley model based on the purging flow rate(QPFR),by using computational fluid dynamics(CFD)simulations.The model quantifies the outdoor risk in 2D street canyons with different approaching wind speeds,urban heating patterns and aspect ratios(building height to street width).We show that urban morphology plays a critical role in controlling airborne infectious disease transmission in outdoor environments,especially under calm winds;with deep street canyons(aspect ratio>3)having a similar infection risk as typical indoor environments.While ground and leeward wall heating could reduce the risk,windward heating(e.g.,windward wall~10 K warmer than the ambient air)can increase the infection risk by up to 75%.Our research highlights the importance of considering outdoor infection risk and the critical role of urban morphology in mitigating airborne infection risk.By identifying and addressing these risks,we can inform measures that may enhance public health and safety,particularly in densely populated urban environments.展开更多
There exist various vertical temperature gradients in different-type buildings.A holistic understanding of the impact of different temperature-stratified indoor environments on infection risk is necessary.In this work...There exist various vertical temperature gradients in different-type buildings.A holistic understanding of the impact of different temperature-stratified indoor environments on infection risk is necessary.In this work,the airborne transmission risk of SARS-CoV-2 in different thermally stratified indoor environments is assessed using our previously developed airborne infection risk model.Results show that the vertical temperature gradients in office building,hospital,classroom,etc.are within the range of−0.34 to 3.26℃/m.In large space such as coach station,airport terminal,and sport hall,the average temperature gradient ranges within 0.13–2.38℃/m in occupied zone(0–3 m);in ice rink with special requirements of indoor environment,the temperature gradient is higher than those in the above indoor spaces.The existence of temperature gradients causes multi-peaks of the transmission risk of SARS-CoV-2 with distancing,and our results show that in office,hospital ward and classroom,the second peak of the transmission risk is higher than 10^(−3)in most contact scenarios,while most being lower than 10^(−6)in large spaces like coach station and airport.The work is expected to provide some guidance on specific intervention policies in relation to the types of indoor environments.展开更多
To the Editor:Osteosarcoma(OS),a disease seriously endangering the health of young people,is the eighth most common primary malignant bone tumor affecting children and adolescents.Typically occurring in the metaphysis...To the Editor:Osteosarcoma(OS),a disease seriously endangering the health of young people,is the eighth most common primary malignant bone tumor affecting children and adolescents.Typically occurring in the metaphysis of long tubular bone,OS develops from mesenchymal cells and accounts for 20%of primary bone tumors.About 70%to 80%of patients are 8 to 9 years.展开更多
Shoulder stiffness(SS)is a common shoulder disease characterized by increasing pain and limited range of motion.SS is considered to be an inflammatory and fibrotic disorder pathologically.However,there is no consensus...Shoulder stiffness(SS)is a common shoulder disease characterized by increasing pain and limited range of motion.SS is considered to be an inflammatory and fibrotic disorder pathologically.However,there is no consensus on the most effective conservative treatment for fibrosis.Given that human Bone Marrow Mesen-chymal Stem Cell-derived extracellular vesicles(BMSC-EVs)displayed promising therapeutic effects for various tissues,we investigated the therapeutic effect of BMSC-EVs on fibrosis in a mice immobilization model and two cell models.By conducting a series of experiments,we found that BMSC-EVs can significantly inhibit the fibrogenic process both in vitro and in vivo.In detail,BMSC-EVs suppressed the aberrant proliferation,high collagen production capacity,and activation of fibrotic pathways in TGF-β-stimulated fibroblasts in vitro.Besides,in vivo,BMSC-EVs reduced cell infiltration,reduced fibrotic tissue in the shoulder capsule,and improved shoulder mobility.In addition,via exosomal small RNA sequencing and qPCR analysis,let-7a-5p was verified to be the highest expressed miRNA with predicted antifibrotic capability in BMSC-EVs.The antifibrotic capacity of BMSC-EVs was significantly impaired after the knockdown of let-7a-5p.Moreover,we discovered that the mRNA of TGFBR1(the membrane receptor of transforming growth factorβ)was the target of let-7a-5p.Together,these findings elucidated the antifibrotic role of BMSC-EVs in shoulder capsular fibrosis.This study clarifies a new approach using stem cell-derived EVs therapy as an alternative to cell therapy,which may clinically benefit patients with SS in the future.展开更多
New U-Pb zircon geochronology data suggest that the Yintun Formation is younger man ~ 1895 Ma and is late Paleoproterozoic.The Yintun Formation may represent the first sedimentary cover of the North China Craton(NCC)b...New U-Pb zircon geochronology data suggest that the Yintun Formation is younger man ~ 1895 Ma and is late Paleoproterozoic.The Yintun Formation may represent the first sedimentary cover of the North China Craton(NCC)based on its stratigraphic sequence and the ages of its sediments.Gravels in the conglomerates from the lower member of the Yintun Formation are characterized by obvious glacial origins.It is possible that these glacial gravels are the re-deposited sedimentary products of the Huronian Glaciation from the Indian continent.This can also provide sedimentary evidence for the relative location of the Indian continent and the NCC in the reconstruction of the Columbia supercontinent.展开更多
The liver is the most common metastatic site for patients with colorectal cancer(CRC),and over 50%of cases show liver metastases.Furthermore,approximately 15-25%of CRC patients present with liver metastases at the tim...The liver is the most common metastatic site for patients with colorectal cancer(CRC),and over 50%of cases show liver metastases.Furthermore,approximately 15-25%of CRC patients present with liver metastases at the time of diagnosis,and liver metastases are the primary cause of death in CRC patients.Although they lacked results from large-sample,prospective clinical trials,retrospective studies in the 1990s showed that hepatectomy is associated with long-term survival in patients with CRC liver metastases(CRLM),who benefited from a 5-year survival rate of more than 50%(1,2).However,the 5-year survival rate of inoperable patients is less than 10%.展开更多
基金supported by National Defense Basic Scientific Research Funding Project(No.JCKY2022203C048)Equipment Advanced Research Funding Program(No.41423010401).
文摘Mainly for the problem that the friction force generated by the existing process of bind-ing,fixing and fastening the flexible cable on the satellite is unknown,the friction force analysis and experimental research on the binding point of the flexible cable are carried out.The equivalent model of the cable bundle bound by nylon cable ties is established,the force on the binding point is analyzed,and the empirical formula for calculating the friction force at the binding point is estab-lished.The formula shows that the friction force is related to the cable bundle diameter,the number of winding cycles of silicone rubber tape,the width of nylon cable ties,and the binding force.The friction force tests of the cable diameter of 5.06 mm,8.02 mm,24.02 mm,38.04 mm under different winding turns of tape were carried out,which was compared with the theoretical calculation value.It is concluded that the calculation accuracy of the theoretical model is more than 95%,which can estimate the actual friction force value accurately.This provides a reference and basis for the theoretical and experimental research on the friction force of the flexible cable binding point on satellite.
基金supported by the State Science and Technology Major Project(2009ZX05009-001)
文摘Apatite fission track(AFT)analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain,northwest China.AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths(11.0e13.2 mm)mostly showing unimodal distribution are shorten,indicating significant track-annealing.Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassiceearly Cretaceous and the OligoceneeMiocene.Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas.The fission-track ages of the southwest area are relatively older(>100 Ma),recording the earlier rapid uplift phase during the late JurassiceCretaceous,while the ages in the north piedmont of the Bogda Mountain(namely the northeast part)are younger(<60 Ma),mainly reflecting the later rapid uplift phase in the OligoceneeMiocene.The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest.In the thrust fault-dominated northern limbs of the Bogda Mountain,AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones,showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic.The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic,respectively.
文摘Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The disease is caused by Candidatus Liberibacter spp., which is vectored by the psyllids Diaphorina citri Kuwayama and Trioza erytreae. Secretory proteins are important in bacterial pathogenesis and structure components. Some of them are expressed at a high level. To obtain the highly-expressed secretory protein genes (SPGs) for antiserum preparation, six candidate SPGs were chosen from Candidatus Liberibacter asiaticus by bioinformatic analysis and were further tested by qPCR and RT-qPCR methods, respectively. The result showed that two SPGs, 408 and pap (both are Flp pilus assembly protein genes), have relative high amounts of DNA and RNA transcripts of early HLB-infected green orange leaves. The 408 and pap genes were further constructed into the plant expression vector pCAMBIA1300 (GV1300: GFP) and expressed in tobacco leaf epidermal cells for subcellular localization analysis. The transient expression results indicated that the 408 protein is located in the nuclei and cytoplasm of tobacco leaf cells. However, the pap protein is located in the cytoplasm of tobacco leaf cells, which may help the pathogen invade into plant cells. This research is an important foundation for the preparation of the antiserum against Candidatus Liberibacter asiaticus and the early detection of HLB disease.
文摘Despite the widespread assumption that outdoor environments provide sufficient ventilation and dilution capacity to mitigate the risk of COVID-19 infection,there is little understanding of airborne infection risk in outdoor urban areas with poor ventilation.To address this gap,we propose a modified Wells-Riley model based on the purging flow rate(QPFR),by using computational fluid dynamics(CFD)simulations.The model quantifies the outdoor risk in 2D street canyons with different approaching wind speeds,urban heating patterns and aspect ratios(building height to street width).We show that urban morphology plays a critical role in controlling airborne infectious disease transmission in outdoor environments,especially under calm winds;with deep street canyons(aspect ratio>3)having a similar infection risk as typical indoor environments.While ground and leeward wall heating could reduce the risk,windward heating(e.g.,windward wall~10 K warmer than the ambient air)can increase the infection risk by up to 75%.Our research highlights the importance of considering outdoor infection risk and the critical role of urban morphology in mitigating airborne infection risk.By identifying and addressing these risks,we can inform measures that may enhance public health and safety,particularly in densely populated urban environments.
基金supported by Shanghai Sailing Program(No.23YF1428700)Sixue Program of University of Shanghai for Science and Technology(No.2022-SX-036).
文摘There exist various vertical temperature gradients in different-type buildings.A holistic understanding of the impact of different temperature-stratified indoor environments on infection risk is necessary.In this work,the airborne transmission risk of SARS-CoV-2 in different thermally stratified indoor environments is assessed using our previously developed airborne infection risk model.Results show that the vertical temperature gradients in office building,hospital,classroom,etc.are within the range of−0.34 to 3.26℃/m.In large space such as coach station,airport terminal,and sport hall,the average temperature gradient ranges within 0.13–2.38℃/m in occupied zone(0–3 m);in ice rink with special requirements of indoor environment,the temperature gradient is higher than those in the above indoor spaces.The existence of temperature gradients causes multi-peaks of the transmission risk of SARS-CoV-2 with distancing,and our results show that in office,hospital ward and classroom,the second peak of the transmission risk is higher than 10^(−3)in most contact scenarios,while most being lower than 10^(−6)in large spaces like coach station and airport.The work is expected to provide some guidance on specific intervention policies in relation to the types of indoor environments.
基金National Natural Science Foundation of China(Nos.81860472 and 81560435)Natural Science Foundation of Jiangxi Province(No.20192ACBL21041)
文摘To the Editor:Osteosarcoma(OS),a disease seriously endangering the health of young people,is the eighth most common primary malignant bone tumor affecting children and adolescents.Typically occurring in the metaphysis of long tubular bone,OS develops from mesenchymal cells and accounts for 20%of primary bone tumors.About 70%to 80%of patients are 8 to 9 years.
文摘Shoulder stiffness(SS)is a common shoulder disease characterized by increasing pain and limited range of motion.SS is considered to be an inflammatory and fibrotic disorder pathologically.However,there is no consensus on the most effective conservative treatment for fibrosis.Given that human Bone Marrow Mesen-chymal Stem Cell-derived extracellular vesicles(BMSC-EVs)displayed promising therapeutic effects for various tissues,we investigated the therapeutic effect of BMSC-EVs on fibrosis in a mice immobilization model and two cell models.By conducting a series of experiments,we found that BMSC-EVs can significantly inhibit the fibrogenic process both in vitro and in vivo.In detail,BMSC-EVs suppressed the aberrant proliferation,high collagen production capacity,and activation of fibrotic pathways in TGF-β-stimulated fibroblasts in vitro.Besides,in vivo,BMSC-EVs reduced cell infiltration,reduced fibrotic tissue in the shoulder capsule,and improved shoulder mobility.In addition,via exosomal small RNA sequencing and qPCR analysis,let-7a-5p was verified to be the highest expressed miRNA with predicted antifibrotic capability in BMSC-EVs.The antifibrotic capacity of BMSC-EVs was significantly impaired after the knockdown of let-7a-5p.Moreover,we discovered that the mRNA of TGFBR1(the membrane receptor of transforming growth factorβ)was the target of let-7a-5p.Together,these findings elucidated the antifibrotic role of BMSC-EVs in shoulder capsular fibrosis.This study clarifies a new approach using stem cell-derived EVs therapy as an alternative to cell therapy,which may clinically benefit patients with SS in the future.
基金funded by the National Key Basic Research Program of China(2013CB429806)
文摘New U-Pb zircon geochronology data suggest that the Yintun Formation is younger man ~ 1895 Ma and is late Paleoproterozoic.The Yintun Formation may represent the first sedimentary cover of the North China Craton(NCC)based on its stratigraphic sequence and the ages of its sediments.Gravels in the conglomerates from the lower member of the Yintun Formation are characterized by obvious glacial origins.It is possible that these glacial gravels are the re-deposited sedimentary products of the Huronian Glaciation from the Indian continent.This can also provide sedimentary evidence for the relative location of the Indian continent and the NCC in the reconstruction of the Columbia supercontinent.
基金This work was supported by Beijing CSCO Clinical Oncology Research Foundation CSCO-Linghang Project(Y-2019AZMS-0082)and the Capital’s Funds for Health Improvement and Research(2018-1-4021).
文摘The liver is the most common metastatic site for patients with colorectal cancer(CRC),and over 50%of cases show liver metastases.Furthermore,approximately 15-25%of CRC patients present with liver metastases at the time of diagnosis,and liver metastases are the primary cause of death in CRC patients.Although they lacked results from large-sample,prospective clinical trials,retrospective studies in the 1990s showed that hepatectomy is associated with long-term survival in patients with CRC liver metastases(CRLM),who benefited from a 5-year survival rate of more than 50%(1,2).However,the 5-year survival rate of inoperable patients is less than 10%.
