This study evaluates the trace element contents (cadmium, lead, mercury and arsenic) in soils, sediments and rock residues of the artisanal gold mining site of Lite-Bala in the Democratic Republic of Congo. Random sam...This study evaluates the trace element contents (cadmium, lead, mercury and arsenic) in soils, sediments and rock residues of the artisanal gold mining site of Lite-Bala in the Democratic Republic of Congo. Random sampling, physicochemical analysis and analysis of total and soluble trace elements by ICP-OES spectrometry as well as calculations of pollution indices (FE and Igeo) and partition coefficient (kd) were carried out in two areas in the dry season and in the rainy season. The soils and sediments of the site are acidic, oxidizing, poor in organic carbon with clayey to sandy textures. Artisanal gold mining at Lite-Bala does not affect, to date, the cadmium, lead, mercury and arsenic contents of soils and sediments. On the other hand, the presence of these elements in rock residues, even in low levels, and the mechanization of this exploitation will have an impact on them in the long term;in particular for Hg used as an input and whose levels are close to the higher standard in surface soils.展开更多
目的:使用Smile Lite MDP(Smile Lite Mobile Dental Photograph)便携式口腔摄影系统进行前牙美学摄影的应用探索,简化美学摄影,方便医患沟通以及医技交流。方法:使用Smile Lite MDP摄影系统配合智能手机拍摄前牙正面咬合相,对色温参数...目的:使用Smile Lite MDP(Smile Lite Mobile Dental Photograph)便携式口腔摄影系统进行前牙美学摄影的应用探索,简化美学摄影,方便医患沟通以及医技交流。方法:使用Smile Lite MDP摄影系统配合智能手机拍摄前牙正面咬合相,对色温参数设置、Smile Lite MDP灯光组合及灯光强度等拍摄条件进行探索,采用医师及技师盲法评价的问卷调查方式,以视觉模拟评分法量表(visual analogue scale/score,VAS)评估最佳拍摄参数。使用Smile Lite MDP摄影系统在最佳拍摄条件下拍摄口内正面咬合相,分别测量中切牙正面观宽长比以及上前牙正面观宽度比,以数码单反相机拍摄的照片作为对照标准,研究Smile Lite MDP摄影系统对前牙形态还原的准确度。结果:Smile Lite MDP便携摄影系统成像的最佳色彩还原的色温参数为5000 K,最佳变焦倍数为4倍,Smile Lite MDP两侧灯光开启,灯光强度2档,采用该组条件的拍摄效果VAS评分较高,与其他组相比差异有统计学意义(P<0.05)。Smile Lite MDP便携摄影系统使用4倍放大率拍摄和单反相机拍照系统摄影标准参数拍摄上前牙的比例差异无统计学意义(P>0.05)。结论:Smile Lite MDP便携式口腔摄影系统应用于前牙美学分析摄影中能够真实、准确地还原前牙的颜色和形态,可以作为临床工作中简便易行的摄影工具。展开更多
文摘This study evaluates the trace element contents (cadmium, lead, mercury and arsenic) in soils, sediments and rock residues of the artisanal gold mining site of Lite-Bala in the Democratic Republic of Congo. Random sampling, physicochemical analysis and analysis of total and soluble trace elements by ICP-OES spectrometry as well as calculations of pollution indices (FE and Igeo) and partition coefficient (kd) were carried out in two areas in the dry season and in the rainy season. The soils and sediments of the site are acidic, oxidizing, poor in organic carbon with clayey to sandy textures. Artisanal gold mining at Lite-Bala does not affect, to date, the cadmium, lead, mercury and arsenic contents of soils and sediments. On the other hand, the presence of these elements in rock residues, even in low levels, and the mechanization of this exploitation will have an impact on them in the long term;in particular for Hg used as an input and whose levels are close to the higher standard in surface soils.
文摘目的:使用Smile Lite MDP(Smile Lite Mobile Dental Photograph)便携式口腔摄影系统进行前牙美学摄影的应用探索,简化美学摄影,方便医患沟通以及医技交流。方法:使用Smile Lite MDP摄影系统配合智能手机拍摄前牙正面咬合相,对色温参数设置、Smile Lite MDP灯光组合及灯光强度等拍摄条件进行探索,采用医师及技师盲法评价的问卷调查方式,以视觉模拟评分法量表(visual analogue scale/score,VAS)评估最佳拍摄参数。使用Smile Lite MDP摄影系统在最佳拍摄条件下拍摄口内正面咬合相,分别测量中切牙正面观宽长比以及上前牙正面观宽度比,以数码单反相机拍摄的照片作为对照标准,研究Smile Lite MDP摄影系统对前牙形态还原的准确度。结果:Smile Lite MDP便携摄影系统成像的最佳色彩还原的色温参数为5000 K,最佳变焦倍数为4倍,Smile Lite MDP两侧灯光开启,灯光强度2档,采用该组条件的拍摄效果VAS评分较高,与其他组相比差异有统计学意义(P<0.05)。Smile Lite MDP便携摄影系统使用4倍放大率拍摄和单反相机拍照系统摄影标准参数拍摄上前牙的比例差异无统计学意义(P>0.05)。结论:Smile Lite MDP便携式口腔摄影系统应用于前牙美学分析摄影中能够真实、准确地还原前牙的颜色和形态,可以作为临床工作中简便易行的摄影工具。
