Simple and inexpensive estimation of the rates and sources of atmospheric nitrogen(N)deposition is critical for its effective mitigation in a region with different land-use types.In this study,the N content and N isot...Simple and inexpensive estimation of the rates and sources of atmospheric nitrogen(N)deposition is critical for its effective mitigation in a region with different land-use types.In this study,the N content and N isotopic composition(δ15N)of moss(Haplocladium microphyllum)tissues and precipitation at six sites with three land-use types(urban,suburban,and rural)were measured in the Yangtze River Delta.A significant linear relationship between moss N content and wet N deposition,and a consistent decrease trend for moss N content and wet N deposition from urban to suburban to rural areas were observed.More negativeδ15N of suburban and rural mosses indicated N mainly released from agriculture and effluent,while the less negativeδ15N of urban mosses were mainly influenced by fossil fuel combustion and traffic emissions.Although the negative mossδ15N indicates that reduced N dominates wet N deposition,there was no significant correlation between mossδ15N and the ratio of ammonium to nitrate(NH4+/NO3−).These results reveal that the moss N content andδ15N can be used as a complementary tool for estimating the rates and sources of wet N deposition in a region with different land-use types.展开更多
目的:分析我院重症监护病房(intensive care unit,ICU)患者呼吸机相关性肺炎(ventilator associated pneumonia,VAP)的病原学特征,为临床感染预防和治疗提供参考。方法:回顾性分析我院ICU进行有创机械通气,确诊为VAP的298例患者资料,采...目的:分析我院重症监护病房(intensive care unit,ICU)患者呼吸机相关性肺炎(ventilator associated pneumonia,VAP)的病原学特征,为临床感染预防和治疗提供参考。方法:回顾性分析我院ICU进行有创机械通气,确诊为VAP的298例患者资料,采集呼吸道分泌物,分析病原菌构成。结果:298例VAP患者样本中检测到病原菌345株,革兰阴性菌占73.91%,革兰阳性菌占26.09%,真菌感染少见。常见的是鲍曼不动杆菌(13.62%)、肺炎克雷伯菌(13.04%)、大肠埃希菌(11.59%)、铜绿假单胞菌(3.19%)、金黄色葡萄球菌(13.33%)、肺炎链球菌(8.99%)、白色假丝酵母菌(2.61%)。其中革兰阴性菌耐药菌占69.02%。结论:ICU患者VAP致病菌以革兰阴性菌为主,主要是耐药菌,做好综合防控具有重要意义。展开更多
背景与目的:肿瘤部位的精准放疗取决于治疗靶区精准的剂量分布,探究使用不同计算机体层成像值-相对电子密度(computed tomography value to the relative electron density,CT-RED)校准曲线对计算各部位肿瘤剂量分布的影响,同时探索拟...背景与目的:肿瘤部位的精准放疗取决于治疗靶区精准的剂量分布,探究使用不同计算机体层成像值-相对电子密度(computed tomography value to the relative electron density,CT-RED)校准曲线对计算各部位肿瘤剂量分布的影响,同时探索拟合一条CT-RED校准曲线的方法。方法:使用复旦大学附属肿瘤医院的两台CT定位机分别对CIRS-062型电子密度模体扫描,获得两组不同部位(头、胸、腹)临床扫描协议的CT-RED校准曲线,并综合各曲线优化出一条改良CT-RED曲线。使用原始及改良CT-RED曲线在治疗计划系统(treatment planning system,TPS)中分别计算各病例计划靶区(planning target volume,PTV)(鼻咽癌、肺癌和宫颈癌各16例)和危及器官(organ at risk,OAR)的剂量分布。最后在各肿瘤中选取5例来验证改良CT-RED曲线的可行性。结果:采用不同校准曲线计算出的剂量在腹部和头颈部中差异较小(<1.00%和<1.13%),但在肺部低密度区域有较大差异(2.50%);使用改良CT-RED曲线与标准CT-RED曲线分别计算头、胸和腹部肿瘤获得的剂量分布无显著差异(<1.00%)。结论:计算不同部位肿瘤的剂量分布应选取对应的CT-RED校准曲线。在具有多台CT定位机的中心也可选择改良CT-RED校准曲线方案以降低选错校准曲线的潜在风险。展开更多
基金This study was funded by the National Natural Science Foundation of China[grant numbers 41571324,41673108,41701329,and 41771380]the National Program on Key Basic Research Project(973 Program)[grant number 2014CB953800]+2 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China[grant number 16KJD170001]the Natural Science Foundation of Hainan Province,China[grant number 317190]the CAGS Research Fund[grant numbers YYWF201637,201724].
文摘Simple and inexpensive estimation of the rates and sources of atmospheric nitrogen(N)deposition is critical for its effective mitigation in a region with different land-use types.In this study,the N content and N isotopic composition(δ15N)of moss(Haplocladium microphyllum)tissues and precipitation at six sites with three land-use types(urban,suburban,and rural)were measured in the Yangtze River Delta.A significant linear relationship between moss N content and wet N deposition,and a consistent decrease trend for moss N content and wet N deposition from urban to suburban to rural areas were observed.More negativeδ15N of suburban and rural mosses indicated N mainly released from agriculture and effluent,while the less negativeδ15N of urban mosses were mainly influenced by fossil fuel combustion and traffic emissions.Although the negative mossδ15N indicates that reduced N dominates wet N deposition,there was no significant correlation between mossδ15N and the ratio of ammonium to nitrate(NH4+/NO3−).These results reveal that the moss N content andδ15N can be used as a complementary tool for estimating the rates and sources of wet N deposition in a region with different land-use types.
文摘目的:分析我院重症监护病房(intensive care unit,ICU)患者呼吸机相关性肺炎(ventilator associated pneumonia,VAP)的病原学特征,为临床感染预防和治疗提供参考。方法:回顾性分析我院ICU进行有创机械通气,确诊为VAP的298例患者资料,采集呼吸道分泌物,分析病原菌构成。结果:298例VAP患者样本中检测到病原菌345株,革兰阴性菌占73.91%,革兰阳性菌占26.09%,真菌感染少见。常见的是鲍曼不动杆菌(13.62%)、肺炎克雷伯菌(13.04%)、大肠埃希菌(11.59%)、铜绿假单胞菌(3.19%)、金黄色葡萄球菌(13.33%)、肺炎链球菌(8.99%)、白色假丝酵母菌(2.61%)。其中革兰阴性菌耐药菌占69.02%。结论:ICU患者VAP致病菌以革兰阴性菌为主,主要是耐药菌,做好综合防控具有重要意义。
文摘背景与目的:肿瘤部位的精准放疗取决于治疗靶区精准的剂量分布,探究使用不同计算机体层成像值-相对电子密度(computed tomography value to the relative electron density,CT-RED)校准曲线对计算各部位肿瘤剂量分布的影响,同时探索拟合一条CT-RED校准曲线的方法。方法:使用复旦大学附属肿瘤医院的两台CT定位机分别对CIRS-062型电子密度模体扫描,获得两组不同部位(头、胸、腹)临床扫描协议的CT-RED校准曲线,并综合各曲线优化出一条改良CT-RED曲线。使用原始及改良CT-RED曲线在治疗计划系统(treatment planning system,TPS)中分别计算各病例计划靶区(planning target volume,PTV)(鼻咽癌、肺癌和宫颈癌各16例)和危及器官(organ at risk,OAR)的剂量分布。最后在各肿瘤中选取5例来验证改良CT-RED曲线的可行性。结果:采用不同校准曲线计算出的剂量在腹部和头颈部中差异较小(<1.00%和<1.13%),但在肺部低密度区域有较大差异(2.50%);使用改良CT-RED曲线与标准CT-RED曲线分别计算头、胸和腹部肿瘤获得的剂量分布无显著差异(<1.00%)。结论:计算不同部位肿瘤的剂量分布应选取对应的CT-RED校准曲线。在具有多台CT定位机的中心也可选择改良CT-RED校准曲线方案以降低选错校准曲线的潜在风险。
