The aerosol optical depth （AOD） data from the Moderate Resolution Imaging Spectroradiometer （MODIS） aboard Satellite Aqua, along with the altitude-resolved aerosol subtypes product from the Cloud-Aerosol LIdar wit...The aerosol optical depth （AOD） data from the Moderate Resolution Imaging Spectroradiometer （MODIS） aboard Satellite Aqua, along with the altitude-resolved aerosol subtypes product from the Cloud-Aerosol LIdar with Orthogonal Polarization （CALIOP）, as well as surface PM 10 measurements, were utilized to investigate the dust activities common in springtime of northern China. Specifically, a dust storm episode that occurred over the North China Plain （NCP） during 17-21 March 2010 was identified. The PM 10 concentration at Beijing （39.8 °N, 116.47 °E） reached the peak value of 283 μgm -3 on 20 March 2010 from the background value of 15 μg m-3 measured on 17 March 2010, then dropped to 176 μgm-3 on 21 March 2010. Analysis of the CALIOP aerosol subtypes product showed that numerous large dust plumes floated over northern China, downwind of main desert source regions, and were lifted to altitudes as high as 3.5 km during this time period. The MODIS AOD data provided spatial distributions of dust load, broadly consistent with ground-level PM 10 , especially in cloud free areas. However, inconsistency between the MODIS AOD and surface PM 10 measurements under cloudy conditions did exist, further highlighting the unique capability of the CALIOP lidar. CALIOP can penetrate the cloud layer to give unambiguous and altitude-resolved dust measurements, albeit a relatively long revisit period （16 days） and narrower swath （90 m）. A back trajectory simulation using the Hybrid Single-Particle Lagrangian Integrated Trajectory （HYSPLIT） model was performed, and it was found that the sand-dust storm originated from the Gobi Desert on 18 March 2010 travelled approxi-mately 1200-1500 km day-1 eastward and passed over the NCP on 19 March 2010, in good agreement with previous findings. In addition, the multi-sensor measurements integrated with the HYSPLIT model output formed a three-dimensional view of the transport pathway for this dust episode, indicating that this episode was largely associated wit展开更多
文摘目的:探讨彩色多普勒超声、实时剪切波弹性成像(shear wave elastography,SWE)与乳腺X线钼靶摄影在乳腺癌筛查中的诊断效果及价值。方法:回顾分析2017年11月~2021年2月我院收治的154例乳腺结节女性患者的临床资料,均经手术病理证实154个病灶,行彩色多普勒超声(ultrasound,US)、实时剪切波弹性成像(shear wave elastography,SWE)及乳腺X线钼靶(mammography,MG)检查。金标准为病理诊断结果,对良、恶性结节进行比较,构建检查者工作特征曲线(receiver operating characteristic,ROC),US与MG均采用乳腺影像与报告系统(breast imaging reporting and data system,BI-RADS)进行判读,以3类以下为良性、4A类以上为恶性,SWE取最大杨氏模量值(SWEmax),再运用ROC曲线取得SWEmax恶性结节的临界点,计算US、MG及US联合SWEmax检查的ROC曲线下的面积(area under ROC cure,AUC)、敏感度、特异度、准确率,比较这三种方法的诊断效能。结果:乳腺恶性结节的SWEmax诊断临界点为70.5kPa,US、MG及US联合SWEmax对乳腺良恶性结节的AUC分别为0.73、0.84、0.91。US、MG及US联合SWEmax诊断乳腺恶性结节的灵敏度分别为99.0%、74.7%和93.9%,特异性分别为12.7%、87.3%、78.2%,准确性分别为68.2%、79.2%、88.3%。结论:US联合SWEmax能明显提高超声检查的特异性和准确性,减少穿刺活检的手术率,为患者提供更优质的检查方案。
基金Supported by the National Basic Research and Development (973) Program of China (2011CB403401)National Science and Technology Support Program of China (2008BAC40B02)+2 种基金China Meteorological Administration Special Public Welfare Research Fund (GYHY200804020 and GYHY201206040)National Natural Science Foundation of China (41171294)Research Fund of the Chinese Academy of Meteorological Sciences (2010Z002 and 2011Y002)
文摘The aerosol optical depth （AOD） data from the Moderate Resolution Imaging Spectroradiometer （MODIS） aboard Satellite Aqua, along with the altitude-resolved aerosol subtypes product from the Cloud-Aerosol LIdar with Orthogonal Polarization （CALIOP）, as well as surface PM 10 measurements, were utilized to investigate the dust activities common in springtime of northern China. Specifically, a dust storm episode that occurred over the North China Plain （NCP） during 17-21 March 2010 was identified. The PM 10 concentration at Beijing （39.8 °N, 116.47 °E） reached the peak value of 283 μgm -3 on 20 March 2010 from the background value of 15 μg m-3 measured on 17 March 2010, then dropped to 176 μgm-3 on 21 March 2010. Analysis of the CALIOP aerosol subtypes product showed that numerous large dust plumes floated over northern China, downwind of main desert source regions, and were lifted to altitudes as high as 3.5 km during this time period. The MODIS AOD data provided spatial distributions of dust load, broadly consistent with ground-level PM 10 , especially in cloud free areas. However, inconsistency between the MODIS AOD and surface PM 10 measurements under cloudy conditions did exist, further highlighting the unique capability of the CALIOP lidar. CALIOP can penetrate the cloud layer to give unambiguous and altitude-resolved dust measurements, albeit a relatively long revisit period （16 days） and narrower swath （90 m）. A back trajectory simulation using the Hybrid Single-Particle Lagrangian Integrated Trajectory （HYSPLIT） model was performed, and it was found that the sand-dust storm originated from the Gobi Desert on 18 March 2010 travelled approxi-mately 1200-1500 km day-1 eastward and passed over the NCP on 19 March 2010, in good agreement with previous findings. In addition, the multi-sensor measurements integrated with the HYSPLIT model output formed a three-dimensional view of the transport pathway for this dust episode, indicating that this episode was largely associated wit
