The efficiency of EDTA, HNO3 and CaCl2 as extractants to remove Pb, Zn and Cu from tailing soils without varying soil pH was investigated with distributions of Pb, Zn and Cu being determined before and after extractio...The efficiency of EDTA, HNO3 and CaCl2 as extractants to remove Pb, Zn and Cu from tailing soils without varying soil pH was investigated with distributions of Pb, Zn and Cu being determined before and after extraction using the sequential extraction procedure of the optimized European Community Bureau of Reference (BCR). Results indicated that EDTA and HNO3 were both effective extracting agents.The extractability of extractants for Pb and Zn was in the order EDTA > HNO3 > CaCl2, while for Cu it was HNO3 > EDTA > CaCl2. After EDTA extraction, the proportion of Pb, Zn and Cu in the four fractions varied greatly, which was related to the strong extraction and complexation ability. Before and after extraction with HNO3 and CaCl2, the percentages of Pb, Zn and Cu in the reducible, oxidizable and residual fractions changed little compared to the acid-extractable fraction. The lability of metal in the soil and the kinds of extractants were the factors controlling the effects of metal extraction.展开更多
目的分析中国健康定量CT大数据(China Biobank)相关数据,旨在建立中国人群腰椎骨密度(bone mineral density,BMD)的正常参考值数据库。方法2018年6月到2019年6月,China Biobank共纳入69811例低剂量胸部CT肺癌筛查健康体检志愿者。所有...目的分析中国健康定量CT大数据(China Biobank)相关数据,旨在建立中国人群腰椎骨密度(bone mineral density,BMD)的正常参考值数据库。方法2018年6月到2019年6月,China Biobank共纳入69811例低剂量胸部CT肺癌筛查健康体检志愿者。所有志愿者按照统一设定定量CT(quantitative CT,QCT)扫描参数扫描,采用QCT Pro测量腰1和腰2椎体中心松质骨体积骨密度(volumetric bone mineral density,vBMD)。结果最终纳入64377例研究对象中,男性38013例(59.05%),女性26364例(40.95%)。随着年龄增长,BMD呈下降趋势,女性椎体松质骨BMD在青中年时期高于男性,但BMD下降趋势高于男性。50岁以上人群骨质疏松症总患病率(年龄标化)男性为13.53%,女性为28.99%;65岁以上人群骨质疏松症总患病率(年龄标化)男性为28.69%,女性为58.69%。50岁以后女性骨质疏松症患病率显著上升,明显高于男性。华东和华南区域男女性椎体松质骨BMD相对较高。体质量指数(body mass index,BMI)与椎体vBMD间未发现明显相关性。结论中国人群QCT腰椎BMD正常参考数据库的建立为QCT的临床应用提供了依据。QCT测量椎体BMD与性别、年龄和地区相关,而与体质量无明显相关。展开更多
基金Project supported by the National High Technology Research and Development Program (863 Program) of China(No. 2001AA644020)the Natural Science Foundation of Hunan Province (No. 04JJ3013)
文摘The efficiency of EDTA, HNO3 and CaCl2 as extractants to remove Pb, Zn and Cu from tailing soils without varying soil pH was investigated with distributions of Pb, Zn and Cu being determined before and after extraction using the sequential extraction procedure of the optimized European Community Bureau of Reference (BCR). Results indicated that EDTA and HNO3 were both effective extracting agents.The extractability of extractants for Pb and Zn was in the order EDTA > HNO3 > CaCl2, while for Cu it was HNO3 > EDTA > CaCl2. After EDTA extraction, the proportion of Pb, Zn and Cu in the four fractions varied greatly, which was related to the strong extraction and complexation ability. Before and after extraction with HNO3 and CaCl2, the percentages of Pb, Zn and Cu in the reducible, oxidizable and residual fractions changed little compared to the acid-extractable fraction. The lability of metal in the soil and the kinds of extractants were the factors controlling the effects of metal extraction.
文摘目的分析中国健康定量CT大数据(China Biobank)相关数据,旨在建立中国人群腰椎骨密度(bone mineral density,BMD)的正常参考值数据库。方法2018年6月到2019年6月,China Biobank共纳入69811例低剂量胸部CT肺癌筛查健康体检志愿者。所有志愿者按照统一设定定量CT(quantitative CT,QCT)扫描参数扫描,采用QCT Pro测量腰1和腰2椎体中心松质骨体积骨密度(volumetric bone mineral density,vBMD)。结果最终纳入64377例研究对象中,男性38013例(59.05%),女性26364例(40.95%)。随着年龄增长,BMD呈下降趋势,女性椎体松质骨BMD在青中年时期高于男性,但BMD下降趋势高于男性。50岁以上人群骨质疏松症总患病率(年龄标化)男性为13.53%,女性为28.99%;65岁以上人群骨质疏松症总患病率(年龄标化)男性为28.69%,女性为58.69%。50岁以后女性骨质疏松症患病率显著上升,明显高于男性。华东和华南区域男女性椎体松质骨BMD相对较高。体质量指数(body mass index,BMI)与椎体vBMD间未发现明显相关性。结论中国人群QCT腰椎BMD正常参考数据库的建立为QCT的临床应用提供了依据。QCT测量椎体BMD与性别、年龄和地区相关,而与体质量无明显相关。
