The existence of an intensifying shift in the East Asian summer monsoon(EASM)since~2000 years ago that differs from the decreasing trend of Northern Hemisphere summer insolation remains controversial.Therefore,we comp...The existence of an intensifying shift in the East Asian summer monsoon(EASM)since~2000 years ago that differs from the decreasing trend of Northern Hemisphere summer insolation remains controversial.Therefore,we compared and synthesized stalagmiteδ^(18)O records from eastern China to clarify the EASM trend during this period.A total of 30 caveδ^(18)O records that did not consistently indicate a depleted trend during 2-0 ka.Rather,they included increasing(14 caves),decreasing(8 caves),and non-significant(8 caves)trends.The spatially interpolated trends of caveδ^(18)O suggested spatial differences among three subregions:North China(NC),decreasing trend(5 caves);Central-East China/Yangtze River Valley(CEC),increasing trend(17 caves);South China(SC),decreasing trend(8 caves).The caveδ^(18)O evidence supports spatial differences in precipitation in eastern China that have been substantially demonstrated by observations and model simulations.The decreasingδ^(18)O anomaly from NC and SC was associated with the decreasing sea surface temperature over Pacific Decadal Oscillation region and increasing South Oscillation Index.The increasing CECδ^(18)O anomaly was linked to southward Intertropical Convergence Zone shift and decreasing solar irradiance.Consequently,EASM circulation is jointly forced by external and internal factors at various timescales.展开更多
Background:Vascular thrombus is a common complication in cancer patients and can be classified as benign or neoplastic based on tumor cell presence.Conventional imaging modalities provide anatomical information but ex...Background:Vascular thrombus is a common complication in cancer patients and can be classified as benign or neoplastic based on tumor cell presence.Conventional imaging modalities provide anatomical information but exhibit limited specificity in distinguishing neoplastic from benign thrombi,prompting the evaluation of 2‐deoxy‐2‐[^(18)F]fluoro‐D‐glucose positron emission tomography/computed tomography([^(18)F]FDG PET/CT),which leverages metabolic differences for improved differentiation.In this study,the efficacy of[^(18)F]FDG PET/CT for differentiating neoplastic thrombus from benign thrombus was evaluated in patients with malignant tumors.Methods:Sixty‐five patients with histologically or clinically confirmed neoplastic or benign thrombus who underwent[^(18)F]FDG PET/CT were retrospectively enrolled.Both visual and semi‐quantitative analyses of the PET/CT scans were conducted.The difference in maximum standardized uptake value(SUVmax)between neoplastic and benign thrombus was assessed using a t‐test.Furthermore,receiver operating characteristics(ROC)analysis was performed to determine the optimal SUVmax threshold for differentiating neoplastic from benign thrombus.Results:Within the cohort,55 patients were diagnosed with neoplastic thrombus and 10 patients with benign thrombus.In the visual analysis,the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy of[^(18)F]FDG PET/CT for diagnosing neoplastic thrombus were 96.4%,90.0%,98.1%,81.8%,and 95.4%,respectively.In the semiquantitative analysis,the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy for diagnosing neoplastic thrombus were 96.4%,100%,100%,83.3%,and 96.9%,respectively.The normalized SUVmax of neoplastic thrombus was significantly higher than that of benign thrombus(10.11�5.32 vs.2.21�0.51,p<0.001).The area under the ROC curves for visual assessment and semi‐quantitative analysis were 0.932 and 0.993,respectively.There was no statistically significant difference observed between these two assessment methods(p=0.317).Conclusions:[^(18)F]FDG PET/CT is capable of differentiating neoplastic thrombus from benign thrombus.Both visual and semiquantitative analyses demonstrated high diagnostic sensitivity,specificity,and accuracy.展开更多
依据乌鲁木齐河流域山区3个站点实测次降水δ18O和δD数据以及气象观测资料,结合临近GNIP(Global Network of Isotopes in Precipitation)站点数据,对其降水δ18O和δD特征及水汽来源进行了分析。结果表明,大气降水中δ18O值波动范围大...依据乌鲁木齐河流域山区3个站点实测次降水δ18O和δD数据以及气象观测资料,结合临近GNIP(Global Network of Isotopes in Precipitation)站点数据,对其降水δ18O和δD特征及水汽来源进行了分析。结果表明,大气降水中δ18O值波动范围大,但呈现明显的季节性变化:冬季降水δ18O较低,夏季降水δ18O较高。受流域山区气候和地理条件影响,从上游到下游各站点大气降水线截距和斜率均呈现逐渐减小趋势。大气降水中δ18O和δD与日均气温存在密切正相关关系,且温度与δ18O之间的相关性优于δD。降水中d-excess值也表现出季节性变化,冬季降水d-excess值高于夏季降水。利用HYSPLIT 4.0气团轨迹模型,得出夏季水汽主要来源西风环流输送,冬季受西风环流和极地气团共同影响。展开更多
基金National Natural Science Foundation of China,No.42225105National Natural Science Foundation of China,No.42471177,No.42201175,No.41901099+1 种基金The Open Foundation of MOE Key Laboratory of Western China's Environmental System,Lanzhou Universitythe Fundamental Research Funds for the Central Universities,No.lzujbky-2022-kb04。
文摘The existence of an intensifying shift in the East Asian summer monsoon(EASM)since~2000 years ago that differs from the decreasing trend of Northern Hemisphere summer insolation remains controversial.Therefore,we compared and synthesized stalagmiteδ^(18)O records from eastern China to clarify the EASM trend during this period.A total of 30 caveδ^(18)O records that did not consistently indicate a depleted trend during 2-0 ka.Rather,they included increasing(14 caves),decreasing(8 caves),and non-significant(8 caves)trends.The spatially interpolated trends of caveδ^(18)O suggested spatial differences among three subregions:North China(NC),decreasing trend(5 caves);Central-East China/Yangtze River Valley(CEC),increasing trend(17 caves);South China(SC),decreasing trend(8 caves).The caveδ^(18)O evidence supports spatial differences in precipitation in eastern China that have been substantially demonstrated by observations and model simulations.The decreasingδ^(18)O anomaly from NC and SC was associated with the decreasing sea surface temperature over Pacific Decadal Oscillation region and increasing South Oscillation Index.The increasing CECδ^(18)O anomaly was linked to southward Intertropical Convergence Zone shift and decreasing solar irradiance.Consequently,EASM circulation is jointly forced by external and internal factors at various timescales.
基金supported by the National Natural Science Foundation of China(Grant 32027802)the Key R&D Program of Zhejiang(Grant 2022C03071)the Fundamental Research Funds for the Central Universities(Grant 226‐2024‐00059).
文摘Background:Vascular thrombus is a common complication in cancer patients and can be classified as benign or neoplastic based on tumor cell presence.Conventional imaging modalities provide anatomical information but exhibit limited specificity in distinguishing neoplastic from benign thrombi,prompting the evaluation of 2‐deoxy‐2‐[^(18)F]fluoro‐D‐glucose positron emission tomography/computed tomography([^(18)F]FDG PET/CT),which leverages metabolic differences for improved differentiation.In this study,the efficacy of[^(18)F]FDG PET/CT for differentiating neoplastic thrombus from benign thrombus was evaluated in patients with malignant tumors.Methods:Sixty‐five patients with histologically or clinically confirmed neoplastic or benign thrombus who underwent[^(18)F]FDG PET/CT were retrospectively enrolled.Both visual and semi‐quantitative analyses of the PET/CT scans were conducted.The difference in maximum standardized uptake value(SUVmax)between neoplastic and benign thrombus was assessed using a t‐test.Furthermore,receiver operating characteristics(ROC)analysis was performed to determine the optimal SUVmax threshold for differentiating neoplastic from benign thrombus.Results:Within the cohort,55 patients were diagnosed with neoplastic thrombus and 10 patients with benign thrombus.In the visual analysis,the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy of[^(18)F]FDG PET/CT for diagnosing neoplastic thrombus were 96.4%,90.0%,98.1%,81.8%,and 95.4%,respectively.In the semiquantitative analysis,the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy for diagnosing neoplastic thrombus were 96.4%,100%,100%,83.3%,and 96.9%,respectively.The normalized SUVmax of neoplastic thrombus was significantly higher than that of benign thrombus(10.11�5.32 vs.2.21�0.51,p<0.001).The area under the ROC curves for visual assessment and semi‐quantitative analysis were 0.932 and 0.993,respectively.There was no statistically significant difference observed between these two assessment methods(p=0.317).Conclusions:[^(18)F]FDG PET/CT is capable of differentiating neoplastic thrombus from benign thrombus.Both visual and semiquantitative analyses demonstrated high diagnostic sensitivity,specificity,and accuracy.
文摘依据乌鲁木齐河流域山区3个站点实测次降水δ18O和δD数据以及气象观测资料,结合临近GNIP(Global Network of Isotopes in Precipitation)站点数据,对其降水δ18O和δD特征及水汽来源进行了分析。结果表明,大气降水中δ18O值波动范围大,但呈现明显的季节性变化:冬季降水δ18O较低,夏季降水δ18O较高。受流域山区气候和地理条件影响,从上游到下游各站点大气降水线截距和斜率均呈现逐渐减小趋势。大气降水中δ18O和δD与日均气温存在密切正相关关系,且温度与δ18O之间的相关性优于δD。降水中d-excess值也表现出季节性变化,冬季降水d-excess值高于夏季降水。利用HYSPLIT 4.0气团轨迹模型,得出夏季水汽主要来源西风环流输送,冬季受西风环流和极地气团共同影响。
基金supported by the National Basic Research Program of China (973 Program 2010CB732303)+3 种基金the National Natural Science Foundation of China (21173173 21033006 21373169)the Program for Changjiang Scholars and Innovative Research Team in University (IRT1036)~~
