The Elogo region has been subjected to craft industry and semi-industrial mining for gold-bearing placers, since the colonial times. It is actually undergoing an intensive exploration for a primary gold deposit. The g...The Elogo region has been subjected to craft industry and semi-industrial mining for gold-bearing placers, since the colonial times. It is actually undergoing an intensive exploration for a primary gold deposit. The goal of this study is to contribute to the exploration of the primary gold deposit in the Elogo Region (North-West of Congo Republic). The methodology consisted of characterization of placers deposits by their lithology, mineralogy and the gold grains shape, in order to constrain the source of gold with the respect to the local geology. The results obtained show that alluviums are polygenic and yields seventeen mineral species composed of zircon, olivine, magnetite, ilmenite, gold, garnet, rutile, coltan, cassiterite, monazite, apatite, amphibole, tourmaline, pyrite, limonite, chromite, and amphibole. The morphoscopy of gold grain shows single grains and grains with quartz inclusions that suggest their relationship with quartz veins. The gold grains are flattened, sub-flattened, and rounded. The northern region of Elogo characterized by a dominance of coarser quartz-included gold grains indicates a proximal proparte origin (less than 50 m), while the southern region, showing less coarse and more evolved grains with choc marks, appears to be associated with a distal pro-parte origin (more than 300 m). The multivariate statistical analysis shows seven classes of samples corresponding to the mineralogical paragenesis suggesting various sources, consisting of high-grade metamorphic, granitoids, pegmatites, basic and ultrabasic rocks, and BIFs that provided minerals to the placers. Gold mainly comes from hydrothermal quartz veins and probably from the peptization of gold from the weathering of sulfides occurring in the BIF. In the Elogo region, gold exploration for primary deposits should look for and follow the hydrothermal system developed in this region. Chemical analysis for the gold grains and associated minerals is necessary to better guide the proposed geochemical prospecting.展开更多
Electrochemical measurements were conducted to study the electrochemical behavior of gold （Au） and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any ...Electrochemical measurements were conducted to study the electrochemical behavior of gold （Au） and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any stabilizer, selective dissolution of Au from stibnite and pyrite was only possible at relatively low thiourea concentrations. As Na2SiO3 was added, pyrite started to become active and an oxida- tion peak appeared; the oxidation peaks of axsenopyrite and chalcocite appeared earlier thaxl that of Au. The chalcocite peak shifted in the positive direction and the peak current increased. Stibnite did not show an oxidation peak and its current was nearly zero. Adding Na2SiO3 favored the selective dissolution of Au when its minerals were associated with chalcocite and stibinte. At pH 12, the Au anode dissolution peak current increased with stabilizer concentration. At 0.38 and 0.42 V and for Na2SiO3 concentration below 0.09 M, the current density continuously increased with Na2SiO3 concentration. The Na2SiO3 concentration had to be adequate to stabilize thiourea. When the potential was higher than 0.42 V, the surface of the Au electrode started to passivate. With an additional increase in potential, the presence of Na2SiO3 could not stop the inevitable decomposition of thiourea.展开更多
背景:观察性研究表明他汀类药物可能对骨密度具有保护作用,这使其成为潜在的骨质疏松症治疗药物之一。目的:通过孟德尔随机化方法来评估药物靶点介导的脂质表型与骨密度之间的因果关系。方法:从IEU Open GWAS数据库获取了与他汀类药物...背景:观察性研究表明他汀类药物可能对骨密度具有保护作用,这使其成为潜在的骨质疏松症治疗药物之一。目的:通过孟德尔随机化方法来评估药物靶点介导的脂质表型与骨密度之间的因果关系。方法:从IEU Open GWAS数据库获取了与他汀类药物相关的单核苷酸多态性以及骨密度相关数据。主要分析方法是逆方差加权法,同时也使用了加权中位数法、简单中位数法、加权中值方法和MR-Egger回归法。使用β值和95%CI来评估他汀类药物与骨密度之间的因果关系;另外,进行敏感性分析以验证结果的可靠性,使用Cochran’s Q检验来评估异质性,使用MR-Egger截距检验是否存在水平多效性。使用留一法分析确定是否有单个或多个单核苷酸多态性影响了结果。结果与结论:他汀类药物作用靶点——3-羟基-3-甲基戊二酰辅酶A还原酶介导的低密度脂蛋白胆固醇与足跟定量超声骨密度(β=-0.086,95%CI:-0.117至-0.055,P=5.42×10^(-8))和全身骨密度(β=-0.193,95%CI:-0.288至-0.098,P=7.35×10^(-5))呈显著相关。该研究结果支持了他汀类药物对骨密度的保护作用。这些发现不仅加深了对胆固醇相关基因和骨骼健康关系的理解,还揭示了改善骨密度的潜在治疗靶点。展开更多
文摘The Elogo region has been subjected to craft industry and semi-industrial mining for gold-bearing placers, since the colonial times. It is actually undergoing an intensive exploration for a primary gold deposit. The goal of this study is to contribute to the exploration of the primary gold deposit in the Elogo Region (North-West of Congo Republic). The methodology consisted of characterization of placers deposits by their lithology, mineralogy and the gold grains shape, in order to constrain the source of gold with the respect to the local geology. The results obtained show that alluviums are polygenic and yields seventeen mineral species composed of zircon, olivine, magnetite, ilmenite, gold, garnet, rutile, coltan, cassiterite, monazite, apatite, amphibole, tourmaline, pyrite, limonite, chromite, and amphibole. The morphoscopy of gold grain shows single grains and grains with quartz inclusions that suggest their relationship with quartz veins. The gold grains are flattened, sub-flattened, and rounded. The northern region of Elogo characterized by a dominance of coarser quartz-included gold grains indicates a proximal proparte origin (less than 50 m), while the southern region, showing less coarse and more evolved grains with choc marks, appears to be associated with a distal pro-parte origin (more than 300 m). The multivariate statistical analysis shows seven classes of samples corresponding to the mineralogical paragenesis suggesting various sources, consisting of high-grade metamorphic, granitoids, pegmatites, basic and ultrabasic rocks, and BIFs that provided minerals to the placers. Gold mainly comes from hydrothermal quartz veins and probably from the peptization of gold from the weathering of sulfides occurring in the BIF. In the Elogo region, gold exploration for primary deposits should look for and follow the hydrothermal system developed in this region. Chemical analysis for the gold grains and associated minerals is necessary to better guide the proposed geochemical prospecting.
基金financial support from the National Natural Science Foundation of China(No.51504031)the innovation fund of the General Research Institute for Nonferrous Metals(No.53319)
文摘Electrochemical measurements were conducted to study the electrochemical behavior of gold （Au） and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any stabilizer, selective dissolution of Au from stibnite and pyrite was only possible at relatively low thiourea concentrations. As Na2SiO3 was added, pyrite started to become active and an oxida- tion peak appeared; the oxidation peaks of axsenopyrite and chalcocite appeared earlier thaxl that of Au. The chalcocite peak shifted in the positive direction and the peak current increased. Stibnite did not show an oxidation peak and its current was nearly zero. Adding Na2SiO3 favored the selective dissolution of Au when its minerals were associated with chalcocite and stibinte. At pH 12, the Au anode dissolution peak current increased with stabilizer concentration. At 0.38 and 0.42 V and for Na2SiO3 concentration below 0.09 M, the current density continuously increased with Na2SiO3 concentration. The Na2SiO3 concentration had to be adequate to stabilize thiourea. When the potential was higher than 0.42 V, the surface of the Au electrode started to passivate. With an additional increase in potential, the presence of Na2SiO3 could not stop the inevitable decomposition of thiourea.
文摘背景:观察性研究表明他汀类药物可能对骨密度具有保护作用,这使其成为潜在的骨质疏松症治疗药物之一。目的:通过孟德尔随机化方法来评估药物靶点介导的脂质表型与骨密度之间的因果关系。方法:从IEU Open GWAS数据库获取了与他汀类药物相关的单核苷酸多态性以及骨密度相关数据。主要分析方法是逆方差加权法,同时也使用了加权中位数法、简单中位数法、加权中值方法和MR-Egger回归法。使用β值和95%CI来评估他汀类药物与骨密度之间的因果关系;另外,进行敏感性分析以验证结果的可靠性,使用Cochran’s Q检验来评估异质性,使用MR-Egger截距检验是否存在水平多效性。使用留一法分析确定是否有单个或多个单核苷酸多态性影响了结果。结果与结论:他汀类药物作用靶点——3-羟基-3-甲基戊二酰辅酶A还原酶介导的低密度脂蛋白胆固醇与足跟定量超声骨密度(β=-0.086,95%CI:-0.117至-0.055,P=5.42×10^(-8))和全身骨密度(β=-0.193,95%CI:-0.288至-0.098,P=7.35×10^(-5))呈显著相关。该研究结果支持了他汀类药物对骨密度的保护作用。这些发现不仅加深了对胆固醇相关基因和骨骼健康关系的理解,还揭示了改善骨密度的潜在治疗靶点。
