The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are ...The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are located in the Kwademen-Baguiomo shear zone. This mineralization, located only a few kilometers from the Kwademen gold deposit, is uncharacterized and, together with the latter, could constitute a gold potential capable of being economically exploitable. It is in this sense that this work is carried out with a view to characterizing the gold mineralization of the Baguiomo gold panning site. To carry out this work, we have made direct field measurements, combined with microstructures, and combined all this with data from geochemical rock analysis of the basalts that are the main host formations. Geochemical data show that tholeitic basalts formed from a mantle plume that was emplaced in an oceanic plateau context. Calc-alkaline basalts and andesites are comparable to Paleoproterozoic tholeitic basalts (PTH3), which are slightly enriched in light rare earths. Fertility tests show that these basalts concentrate between 3 and 6 ppb of gold at the time of accretion, which is sufficient for remobilization of this primary gold during the Eburnian orogeny to yield a deposit of around 4 - 5 Moz. Gold mineralization is associated with pyrite crystals when the latter are disseminated in the rock mass, whereas it is associated with hematite in quartz veins concordant with S1 shear deformation. It is mainly the pyrite crystals in the pressure shadows that contain the gold grains, whose development would be synchronous with micro-shear zone reactivation during the first phase of D1<sub>B</sub> deformation. The second phase of D2<sub>B</sub> deformation, which is a crenulation or fracture schistosity, does not significantly affect the shear deformation that controls mineralization.展开更多
Epithelial attachment via the basal lamina on the tooth surface provides an important structural defence mechanism against bacterial invasion in combating periodontal disease. However, when considering dental implants...Epithelial attachment via the basal lamina on the tooth surface provides an important structural defence mechanism against bacterial invasion in combating periodontal disease. However, when considering dental implants, strong epithelial attachment does not exist throughout the titanium-soft tissue interface, making soft tissues more susceptible to peri-implant disease. This study introduced a novel synthetic peptide(A10) to enhance epithelial attachment. A10 was identified from a bacterial peptide display library and synthesized. A10 and protease-activated receptor 4-activating peptide(PAR4-AP, positive control) were immobilized on commercially pure titanium. The peptide-treated titanium showed high epithelial cell migration ability during incubation in platelet-rich plasma. We confirmed the development of dense and expanded BL(stained by Ln5) with pericellular junctions(stained by ZO1) on the peptide-treated titanium surface. In an adhesion assay of epithelial cells on A10-treated titanium, PAR4-AP-treated titanium, bovine root and non-treated titanium, A10-treated titanium and PAR4-AP-treated titanium showed significantly stronger adhesion than non-treated titanium. PAR4-AP-treated titanium showed significantly higher inflammatory cytokine release than non-treated titanium. There was no significant difference in inflammatory cytokine release between A10-treated and non-treated titanium. These results indicated that A10 could induce the adhesion and migration of epithelial cells with low inflammatory cytokine release. This novel peptide has a potentially useful application that could improve clinical outcomes with titanium implants and abutments by reducing or preventing peri-implant disease.展开更多
The sediments collected respectively from the Etó, Kacumvi, Kimbi, Lubichako, Makungu, Kuwa, Mandje, Misisi and Kimuti Rivers draining the gold panning sites in the Fizi territory were studied during a 16-month c...The sediments collected respectively from the Etó, Kacumvi, Kimbi, Lubichako, Makungu, Kuwa, Mandje, Misisi and Kimuti Rivers draining the gold panning sites in the Fizi territory were studied during a 16-month cycle (August and December 2016 to August and December 2017) in order to assess their degree of mercury pollution in the dry season as well as in the rainy season. The assessment of the degree of pollution of the said sediments focused on six parameters including the total mercury content (THg) and the indices of mercury pollution such as the mercury enrichment factor (EF), the mercury contamination factor (CF), the mercury geoaccumulation index (Igeo), the mercury potential ecological risk factor (PERF) and the mercury ecological risk index (ERI). Total mercury was determined by atomic absorption spectrophotometry (AAS) while the mercury pollution indices were successively calculated using the appropriate formulas. The results thus obtained revealed that all the sediments of the rivers studied are considerably polluted by mercury according to the values relative to their total mercury content and mercury pollution indices, including the mercury enrichment factor (EF), the mercury contamination factor (CF), the mercury geoaccumulation index (Igeo), the mercury potential ecological risk factor (PERF) and the mercury ecological risk index (ERI), which greatly exceed the standards recommended by the Canadian Council of Ministers of the Environment. In particular, the sediments of the Kimbi River are highly polluted by mercury compared to those of other rivers studied. This reported pollution is the result of anthropogenic gold panning activities that generate effluents and elemental mercury that pollute the streams.展开更多
High-nickel ternary cathodes hold a great application prospect in solid-state lithium metal batteries to achieve high-energy density,but they still suffer from structural instability and detrimental side reactions wit...High-nickel ternary cathodes hold a great application prospect in solid-state lithium metal batteries to achieve high-energy density,but they still suffer from structural instability and detrimental side reactions with the solid-state electrolytes.To circumvent these issues,a continuous uniform layer polyacrylonitrile(PAN)was introduced on the surface of LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2) via in situ polymerization of acrylonitrile(AN).Furthermore,the partial-cyclized treatment of PAN(cPAN)coating layer presents high ionic and electron conductivity,which can accelerate interfacial Li+and electron diffusion simultaneously.And the thermodynamically stabilized cPAN coating layer cannot only effectively inhibit detrimental side reactions between cathode and solid-state electrolytes but also provide a homogeneous stress to simultaneously address the problems of bulk structural degradation,which contributes to the exceptional mechanical and electrochemical stabilities of the modified electrode.Besides,the coordination bond interaction between the cPAN and NCM811 can suppress the migration of Ni to elevate the stability of the crystal structure.Benefited from these,the In-cPAN-260@NCM811 shows excellent cycling performance with a retention of 86.8%after 300 cycles and superior rate capability.And endow the solid-state battery with thermal safety stability even at hightemperature extreme environment.This facile and scalable surface engineering represents significant progress in developing high-performance solid-state lithium metal batteries.展开更多
High-temperature piezoelectric sen-sors are very important in severe environments such as fire safety,aerospace and oil drills,however,most current sensors are not heat res-istant(<300℃)and are fragile,which limit...High-temperature piezoelectric sen-sors are very important in severe environments such as fire safety,aerospace and oil drills,however,most current sensors are not heat res-istant(<300℃)and are fragile,which limits their use,especially in high-temperature environ-ments.A high-temperature resistant flexible piezoelectric film based on graphene oxide(GO)/polyacrylonitrile(PAN)composites was prepared by electrospinning and thermal treat-ment.It was packed into a micro-device,which could work continuously at 500℃.The intro-duction of GO significantly increased the mechanical properties of the PAN nanofibers because the oxygen-containing func-tional groups(electronegative groups)on the surface of the GO initiated a nucleophilic attack on the PAN molecule during heat treatment,enabling the GO to initiate the cyclization of the PAN at lower heat-treatment temperatures.In addition,the abund-ant oxygen-containing functional groups on GO acted as pro-oxidants to hasten the oxidation of PAN during heat treatment.The effects of GO content and heat treatment temperature on the properties of the nanofiber films were investigated.A GO/PAN nanofiber piezoelectric sensor heat-treated at 300℃had a 9.10 V and 2.25μA peak output,which are respectively 101.3%and 78.6%higher than those of the untreated films.Cyclic testing over 5000 cycles at 350℃confirmed the stable out-put performance of the GO/PAN nanofiber piezoelectric sensor.Furthermore,a sensor heat-treated at 400℃had a sensitivity of 1.7 V/N,which is 83.5%higher than that of an untreated one.The results show that the prepared GO/PAN nanofiber piezo-electric sensor combines high temperature resistance,high flexibility,stability and high sensitivity,and may have broad applic-ations in high temperature environments such as the aerospace and petroleum industries.展开更多
挠曲电效应广泛应用于柔性传感、医疗复健、振动能量收集等领域,然而尚未有研究探讨挠曲形变量对挠曲电响应性能的影响。基于此,以MoS_(2)/PAN复合挠曲电传感薄膜为例,制备MoS_(2)/PAN弯曲传感器,采用X射线衍射仪和扫描电子显微镜对复...挠曲电效应广泛应用于柔性传感、医疗复健、振动能量收集等领域,然而尚未有研究探讨挠曲形变量对挠曲电响应性能的影响。基于此,以MoS_(2)/PAN复合挠曲电传感薄膜为例,制备MoS_(2)/PAN弯曲传感器,采用X射线衍射仪和扫描电子显微镜对复合挠曲电传感薄膜的晶体结构、微观形貌进行表征。在弯曲角度为0.1°、0.5°、1.5°、4°、7°、15°、30°和45°情况下,通过数字源表收集不同弯曲角度下MoS_(2)/PAN弯曲传感器的挠曲响应电压、电流和响应时间,分析挠曲形变量对挠曲电响应性能的影响规律,基于悬臂梁方法测试计算挠曲电系数。结果表明:MoS_(2)/PAN弯曲传感器挠曲电效应显著,挠曲电系数高达1.95 n C/m,当弯曲角度为7°时,MoS_(2)/PAN弯曲传感器获得最优的挠曲电响应,当弯曲角度小于7°时,挠曲电响应随弯曲角度的增大而增大,但是当弯曲角度大于7°时,挠曲电效应减弱。展开更多
The anuran family Ceratobatrachidae is one of the most speciose groups of amphibians,but the geographic distributions of many genera and species await documentation.During the field survey of Tongbiguan Provincial Nat...The anuran family Ceratobatrachidae is one of the most speciose groups of amphibians,but the geographic distributions of many genera and species await documentation.During the field survey of Tongbiguan Provincial Nature Reserve in southwestern Yunnan Province,China,at the China-Myanmar border region,we collected several frogs that resemble the genus Alcalus,which was previously known from Indochina only.Based on mitochondrial phylogeny,our newly collected specimens are sister to Alcalus fontinalis Boruah,Narayanan,Gerard,Das,and Deepak,2023 from Northeast India,but it differs from the latter by a suit of characters,including in differences in body size,head length,snout length,tympanum diameter,eye diameter,forearm length,toe webbing formula,relative length of fingers and toes,and dorsal pattern and coloration.Herein,based on the integration of morphological and genetic data,we report the genus Alcalus from China for the first time and describe a new species from China-Myanmar border region.Our study further demonstrates that southern section of the Gaoligong Mountain has a rich diversity of amphibians that warrant continuous survey efforts.Future fieldwork in these mountains is needed to better understand and fully uncover the species richness in this border region.展开更多
文摘The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are located in the Kwademen-Baguiomo shear zone. This mineralization, located only a few kilometers from the Kwademen gold deposit, is uncharacterized and, together with the latter, could constitute a gold potential capable of being economically exploitable. It is in this sense that this work is carried out with a view to characterizing the gold mineralization of the Baguiomo gold panning site. To carry out this work, we have made direct field measurements, combined with microstructures, and combined all this with data from geochemical rock analysis of the basalts that are the main host formations. Geochemical data show that tholeitic basalts formed from a mantle plume that was emplaced in an oceanic plateau context. Calc-alkaline basalts and andesites are comparable to Paleoproterozoic tholeitic basalts (PTH3), which are slightly enriched in light rare earths. Fertility tests show that these basalts concentrate between 3 and 6 ppb of gold at the time of accretion, which is sufficient for remobilization of this primary gold during the Eburnian orogeny to yield a deposit of around 4 - 5 Moz. Gold mineralization is associated with pyrite crystals when the latter are disseminated in the rock mass, whereas it is associated with hematite in quartz veins concordant with S1 shear deformation. It is mainly the pyrite crystals in the pressure shadows that contain the gold grains, whose development would be synchronous with micro-shear zone reactivation during the first phase of D1<sub>B</sub> deformation. The second phase of D2<sub>B</sub> deformation, which is a crenulation or fracture schistosity, does not significantly affect the shear deformation that controls mineralization.
基金supported by an International Team for Implantology(ITI)grant(grant number:1119_2015)
文摘Epithelial attachment via the basal lamina on the tooth surface provides an important structural defence mechanism against bacterial invasion in combating periodontal disease. However, when considering dental implants, strong epithelial attachment does not exist throughout the titanium-soft tissue interface, making soft tissues more susceptible to peri-implant disease. This study introduced a novel synthetic peptide(A10) to enhance epithelial attachment. A10 was identified from a bacterial peptide display library and synthesized. A10 and protease-activated receptor 4-activating peptide(PAR4-AP, positive control) were immobilized on commercially pure titanium. The peptide-treated titanium showed high epithelial cell migration ability during incubation in platelet-rich plasma. We confirmed the development of dense and expanded BL(stained by Ln5) with pericellular junctions(stained by ZO1) on the peptide-treated titanium surface. In an adhesion assay of epithelial cells on A10-treated titanium, PAR4-AP-treated titanium, bovine root and non-treated titanium, A10-treated titanium and PAR4-AP-treated titanium showed significantly stronger adhesion than non-treated titanium. PAR4-AP-treated titanium showed significantly higher inflammatory cytokine release than non-treated titanium. There was no significant difference in inflammatory cytokine release between A10-treated and non-treated titanium. These results indicated that A10 could induce the adhesion and migration of epithelial cells with low inflammatory cytokine release. This novel peptide has a potentially useful application that could improve clinical outcomes with titanium implants and abutments by reducing or preventing peri-implant disease.
文摘The sediments collected respectively from the Etó, Kacumvi, Kimbi, Lubichako, Makungu, Kuwa, Mandje, Misisi and Kimuti Rivers draining the gold panning sites in the Fizi territory were studied during a 16-month cycle (August and December 2016 to August and December 2017) in order to assess their degree of mercury pollution in the dry season as well as in the rainy season. The assessment of the degree of pollution of the said sediments focused on six parameters including the total mercury content (THg) and the indices of mercury pollution such as the mercury enrichment factor (EF), the mercury contamination factor (CF), the mercury geoaccumulation index (Igeo), the mercury potential ecological risk factor (PERF) and the mercury ecological risk index (ERI). Total mercury was determined by atomic absorption spectrophotometry (AAS) while the mercury pollution indices were successively calculated using the appropriate formulas. The results thus obtained revealed that all the sediments of the rivers studied are considerably polluted by mercury according to the values relative to their total mercury content and mercury pollution indices, including the mercury enrichment factor (EF), the mercury contamination factor (CF), the mercury geoaccumulation index (Igeo), the mercury potential ecological risk factor (PERF) and the mercury ecological risk index (ERI), which greatly exceed the standards recommended by the Canadian Council of Ministers of the Environment. In particular, the sediments of the Kimbi River are highly polluted by mercury compared to those of other rivers studied. This reported pollution is the result of anthropogenic gold panning activities that generate effluents and elemental mercury that pollute the streams.
基金financially supported by the National Natural Science Foundation of China(Nos.22102212 and 22479067).
文摘High-nickel ternary cathodes hold a great application prospect in solid-state lithium metal batteries to achieve high-energy density,but they still suffer from structural instability and detrimental side reactions with the solid-state electrolytes.To circumvent these issues,a continuous uniform layer polyacrylonitrile(PAN)was introduced on the surface of LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2) via in situ polymerization of acrylonitrile(AN).Furthermore,the partial-cyclized treatment of PAN(cPAN)coating layer presents high ionic and electron conductivity,which can accelerate interfacial Li+and electron diffusion simultaneously.And the thermodynamically stabilized cPAN coating layer cannot only effectively inhibit detrimental side reactions between cathode and solid-state electrolytes but also provide a homogeneous stress to simultaneously address the problems of bulk structural degradation,which contributes to the exceptional mechanical and electrochemical stabilities of the modified electrode.Besides,the coordination bond interaction between the cPAN and NCM811 can suppress the migration of Ni to elevate the stability of the crystal structure.Benefited from these,the In-cPAN-260@NCM811 shows excellent cycling performance with a retention of 86.8%after 300 cycles and superior rate capability.And endow the solid-state battery with thermal safety stability even at hightemperature extreme environment.This facile and scalable surface engineering represents significant progress in developing high-performance solid-state lithium metal batteries.
文摘High-temperature piezoelectric sen-sors are very important in severe environments such as fire safety,aerospace and oil drills,however,most current sensors are not heat res-istant(<300℃)and are fragile,which limits their use,especially in high-temperature environ-ments.A high-temperature resistant flexible piezoelectric film based on graphene oxide(GO)/polyacrylonitrile(PAN)composites was prepared by electrospinning and thermal treat-ment.It was packed into a micro-device,which could work continuously at 500℃.The intro-duction of GO significantly increased the mechanical properties of the PAN nanofibers because the oxygen-containing func-tional groups(electronegative groups)on the surface of the GO initiated a nucleophilic attack on the PAN molecule during heat treatment,enabling the GO to initiate the cyclization of the PAN at lower heat-treatment temperatures.In addition,the abund-ant oxygen-containing functional groups on GO acted as pro-oxidants to hasten the oxidation of PAN during heat treatment.The effects of GO content and heat treatment temperature on the properties of the nanofiber films were investigated.A GO/PAN nanofiber piezoelectric sensor heat-treated at 300℃had a 9.10 V and 2.25μA peak output,which are respectively 101.3%and 78.6%higher than those of the untreated films.Cyclic testing over 5000 cycles at 350℃confirmed the stable out-put performance of the GO/PAN nanofiber piezoelectric sensor.Furthermore,a sensor heat-treated at 400℃had a sensitivity of 1.7 V/N,which is 83.5%higher than that of an untreated one.The results show that the prepared GO/PAN nanofiber piezo-electric sensor combines high temperature resistance,high flexibility,stability and high sensitivity,and may have broad applic-ations in high temperature environments such as the aerospace and petroleum industries.
文摘挠曲电效应广泛应用于柔性传感、医疗复健、振动能量收集等领域,然而尚未有研究探讨挠曲形变量对挠曲电响应性能的影响。基于此,以MoS_(2)/PAN复合挠曲电传感薄膜为例,制备MoS_(2)/PAN弯曲传感器,采用X射线衍射仪和扫描电子显微镜对复合挠曲电传感薄膜的晶体结构、微观形貌进行表征。在弯曲角度为0.1°、0.5°、1.5°、4°、7°、15°、30°和45°情况下,通过数字源表收集不同弯曲角度下MoS_(2)/PAN弯曲传感器的挠曲响应电压、电流和响应时间,分析挠曲形变量对挠曲电响应性能的影响规律,基于悬臂梁方法测试计算挠曲电系数。结果表明:MoS_(2)/PAN弯曲传感器挠曲电效应显著,挠曲电系数高达1.95 n C/m,当弯曲角度为7°时,MoS_(2)/PAN弯曲传感器获得最优的挠曲电响应,当弯曲角度小于7°时,挠曲电响应随弯曲角度的增大而增大,但是当弯曲角度大于7°时,挠曲电效应减弱。
基金supported by the National Key R & D Program of China (2022YFC2602500)Science and Technology Basic Resources Investigation Program of China (2021FY100203)+8 种基金National Natural Science Foundation of China (NSFC 32100371,32400374)Program of Yunnan Forestry and Grassland Administration (2022GF258D-10)Yunnan Applied Basic Research Projects (202301AT070312,202301AT070431)Talent and Platform of Science and Technology in Yunnan Province Science and Technology Department (202205AM070007)China’s Biodiversity Observation Network (Sino-BON)the Animal Branch of the Germplasm Bank of Wild Species,CAS (Large Research Infrastructure Funding)CAS Special Research Assistant (SRA) ProgramYunnan Revitalization Talent Support Program (Yunling Scholar Project & Young Talent Project)Small Grants Program for New Records and Rediscoveries of Rare Species initiated by Tencent Foundation and Shanshui Conservation Center。
文摘The anuran family Ceratobatrachidae is one of the most speciose groups of amphibians,but the geographic distributions of many genera and species await documentation.During the field survey of Tongbiguan Provincial Nature Reserve in southwestern Yunnan Province,China,at the China-Myanmar border region,we collected several frogs that resemble the genus Alcalus,which was previously known from Indochina only.Based on mitochondrial phylogeny,our newly collected specimens are sister to Alcalus fontinalis Boruah,Narayanan,Gerard,Das,and Deepak,2023 from Northeast India,but it differs from the latter by a suit of characters,including in differences in body size,head length,snout length,tympanum diameter,eye diameter,forearm length,toe webbing formula,relative length of fingers and toes,and dorsal pattern and coloration.Herein,based on the integration of morphological and genetic data,we report the genus Alcalus from China for the first time and describe a new species from China-Myanmar border region.Our study further demonstrates that southern section of the Gaoligong Mountain has a rich diversity of amphibians that warrant continuous survey efforts.Future fieldwork in these mountains is needed to better understand and fully uncover the species richness in this border region.
