实施综合治理措施是改善流域水环境、提升水质的有效手段之一,进行效果评估是检验治理措施成效的关键。以小清河流域邹平段为研究对象,对3种影响该流域水质的主要污染物(NH_(3)-N、TN、TP)进行治理。根据污染物负荷的来源,从流域的点源...实施综合治理措施是改善流域水环境、提升水质的有效手段之一,进行效果评估是检验治理措施成效的关键。以小清河流域邹平段为研究对象,对3种影响该流域水质的主要污染物(NH_(3)-N、TN、TP)进行治理。根据污染物负荷的来源,从流域的点源、面源及外源提出了不同治理措施并进行5种组合。利用土壤和水评估工具(soil and water assessment tool,SWAT)模型对不同降水情况下5种情景进行模拟,分析各情景中治理措施实施后NH_(3)-N、TN、TP浓度状况,并结合R-R-V(reliability-resilience-vulnerability)指数法和熵值法对不同情景治理措施的治理效果进行综合评价。结果表明:不同措施组合的治理情景均能够改善水质状况,其中S5(城镇污水处理率提高到100%,农村污水处理率提高到80%,裸露地减少30 km^(2),上游负荷减少40%,施肥量减少40%)情景下,唐口桥断面丰水年、平水年和枯水年均达到Ⅲ类水质目标。不同降雨情况下,S5情景综合得分最高,丰水年和平水年均为0.96,枯水年为0.88,该情景的治理措施对水质改善效果最佳。因此,R-R-V指数和熵值法相结合能对综合治理措施的效果进行评价,并为小清河流域邹平段水质管理目标的实现提供治理措施筛选的依据。展开更多
BACKGROUND Iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence(IDEAL-IQ)is based on chemical shift-based water and fat separation technique to get proton d...BACKGROUND Iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence(IDEAL-IQ)is based on chemical shift-based water and fat separation technique to get proton density fat fraction.Multiple studies have shown that using IDEAL-IQ to test the stability and repeatability of liver fat is acceptable and has high accuracy.AIM To explore whether Gadoxetate Disodium(Gd-EOB-DTPA)interferes with the measurement of the hepatic fat content quantified with the IDEAL-IQ and to evaluate the robustness of this technique.METHODS IDEAL-IQ was used to quantify the liver fat content at 3.0T in 65 patients injected with Gd-EOB-DTPA contrast.After injection,IDEAL-IQ was estimated four times,and the fat fraction(FF)and R2* were measured at the following time points:Precontrast,between the portal phase(70 s)and the late phase(180 s),the delayed phase(5 min)and the hepatobiliary phase(20 min).One-way repeated-measures analysis was conducted to evaluate the difference in the FFs between the four time points.Bland-Altman plots were adopted to assess the FF changes before and after injection of the contrast agent.P<0.05 was considered statistically significant.RESULTS The assessment of the FF at the four time points in the liver,spleen and spine showed no significant differences,and the measurements of hepatic FF yielded good consistency between T1 and T2[95%confidence interval:-0.6768%,0.6658%],T1 and T3(-0.3900%,0.3178%),and T1 and T4(-0.3750%,0.2825%).R2* of the liver,spleen and spine increased significantly after injection(P<0.0001).CONCLUSION Using the IDEAL-IQ sequence to measure the FF,we can obtain results that will not be affected by Gd-EOB-DTPA.The high reproducibility of the IDEAL-IQ sequence makes it available in the scanning interval to save time during multiphase examinations.展开更多
文摘实施综合治理措施是改善流域水环境、提升水质的有效手段之一,进行效果评估是检验治理措施成效的关键。以小清河流域邹平段为研究对象,对3种影响该流域水质的主要污染物(NH_(3)-N、TN、TP)进行治理。根据污染物负荷的来源,从流域的点源、面源及外源提出了不同治理措施并进行5种组合。利用土壤和水评估工具(soil and water assessment tool,SWAT)模型对不同降水情况下5种情景进行模拟,分析各情景中治理措施实施后NH_(3)-N、TN、TP浓度状况,并结合R-R-V(reliability-resilience-vulnerability)指数法和熵值法对不同情景治理措施的治理效果进行综合评价。结果表明:不同措施组合的治理情景均能够改善水质状况,其中S5(城镇污水处理率提高到100%,农村污水处理率提高到80%,裸露地减少30 km^(2),上游负荷减少40%,施肥量减少40%)情景下,唐口桥断面丰水年、平水年和枯水年均达到Ⅲ类水质目标。不同降雨情况下,S5情景综合得分最高,丰水年和平水年均为0.96,枯水年为0.88,该情景的治理措施对水质改善效果最佳。因此,R-R-V指数和熵值法相结合能对综合治理措施的效果进行评价,并为小清河流域邹平段水质管理目标的实现提供治理措施筛选的依据。
基金Supported by National Natural Science Foundation of China,No.82272053.
文摘BACKGROUND Iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence(IDEAL-IQ)is based on chemical shift-based water and fat separation technique to get proton density fat fraction.Multiple studies have shown that using IDEAL-IQ to test the stability and repeatability of liver fat is acceptable and has high accuracy.AIM To explore whether Gadoxetate Disodium(Gd-EOB-DTPA)interferes with the measurement of the hepatic fat content quantified with the IDEAL-IQ and to evaluate the robustness of this technique.METHODS IDEAL-IQ was used to quantify the liver fat content at 3.0T in 65 patients injected with Gd-EOB-DTPA contrast.After injection,IDEAL-IQ was estimated four times,and the fat fraction(FF)and R2* were measured at the following time points:Precontrast,between the portal phase(70 s)and the late phase(180 s),the delayed phase(5 min)and the hepatobiliary phase(20 min).One-way repeated-measures analysis was conducted to evaluate the difference in the FFs between the four time points.Bland-Altman plots were adopted to assess the FF changes before and after injection of the contrast agent.P<0.05 was considered statistically significant.RESULTS The assessment of the FF at the four time points in the liver,spleen and spine showed no significant differences,and the measurements of hepatic FF yielded good consistency between T1 and T2[95%confidence interval:-0.6768%,0.6658%],T1 and T3(-0.3900%,0.3178%),and T1 and T4(-0.3750%,0.2825%).R2* of the liver,spleen and spine increased significantly after injection(P<0.0001).CONCLUSION Using the IDEAL-IQ sequence to measure the FF,we can obtain results that will not be affected by Gd-EOB-DTPA.The high reproducibility of the IDEAL-IQ sequence makes it available in the scanning interval to save time during multiphase examinations.
