A survivin small interfering RNA sequence specific for a human and mouse homogenous sequence was constructed.Survivin small interfering RNA could significantly inhibit glioma cell proliferation and induce apoptosis wh...A survivin small interfering RNA sequence specific for a human and mouse homogenous sequence was constructed.Survivin small interfering RNA could significantly inhibit glioma cell proliferation and induce apoptosis when it was transfected into either a human glioma cell line U251 or rat glioma C6 cells in vitro.In addition,treatment of rat orthotopic glioma models with survivin small interfering demonstrated the inhibition of glioma growth in vivo.Our experimental findings suggest that the use of RNA interference techniques to target the survivin sequence may be useful in the treatment of glioma.展开更多
The Bayan Obo deposit in northern China is an ultra-large Fe–REE–Nb deposit.The occurrences,and geochemical characteristics of thorium in iron ores from the Bayan Obo Main Ore Body were examined using chemical analy...The Bayan Obo deposit in northern China is an ultra-large Fe–REE–Nb deposit.The occurrences,and geochemical characteristics of thorium in iron ores from the Bayan Obo Main Ore Body were examined using chemical analysis,field emission scanning electron microscopy,energy dispersive spectrometer,and automatic mineral analysis software.Results identified that 91.69%of ThO2 in the combined samples was mainly distributed in rare earth minerals(bastnaesite,huanghoite,monazite;56.43%abundance in the samples),iron minerals(magnetite,hematite,pyrite;20.97%),niobium minerals(aeschynite;14.29%),and gangue minerals(aegirine,riebeckite,mica,dolomite,apatite,fluorite;4.22%).An unidentified portion(4.09%)of ThO2 may occur in other niobium minerals(niobite,ilmenorutile,pyrochlore).Only a few independent minerals of thorium occur in the iron ore samples.Thorium mainly occurs in rare earth minerals in the form of isomorphic substitution.Analyses of the geochemical characteristics of the major elements indicate that thorium mineralization in the Main Ore Body was related to alkali metasomatism,which provided source material and favorable porosity for hydrothermal mineralization.Trace elements such as Sc,Nb,Zr,and Ta have higher correlation coefficients with thorium,which resulted from being related to the relevant minerals formed during thorium mineralization.In addition,correlation analysis of ThO2 and TFe,and REO and TFe in the six types of iron ore samples showed that ThO2 did not always account for the highest distribution rate in rare earth minerals,and the main occurrence minerals of ThO2 were closely related to iron ore types.展开更多
To understand the status of phytoplankton community of the Genhe River in the summer of 2015,we investigated the phytoplankton in Genhe River. We identified 5 phyla and 36 species,among which Bacillariophyta(23) were ...To understand the status of phytoplankton community of the Genhe River in the summer of 2015,we investigated the phytoplankton in Genhe River. We identified 5 phyla and 36 species,among which Bacillariophyta(23) were the most,followed by Chlorophyta(10),Cyanophyta(1),Chrysophyta(1),Pyrrophyta(1). The phytoplankton abundance was(15. 6-810) × 104 ind·L^(-1); the biomass was(0. 07-2. 876) mg·L-1; Shannon-wiener index was 1. 05-3. 24; Pielou evenness index was 0. 27-0. 96. Using Shannon-wiener index and Pielou index,the water quality of Genhe River was assessed,and the results showed that the water quality was the best at 5# sampling point,the water quality was good in 3#,4#,7#,8#,9# sampling points,and there was a state of pollution at other sampling points. Canonical correspondence analysis and Pearson correlation analysis showed that iron ion,transparency,p H value,water depth and water temperature were important environmental factors that affect the distribution of phytoplankton,and copper ion,nitrite ion and COD also significantly affected the distribution of phytoplankton.展开更多
The flow passage components in hydraulic machinery will be eroded rapidly when running in sand water.The wear resistance of materials commonly used in hydraulic machinery needs to be improved to prevent the failure of...The flow passage components in hydraulic machinery will be eroded rapidly when running in sand water.The wear resistance of materials commonly used in hydraulic machinery needs to be improved to prevent the failure of hydraulic machinery.New wear-resistant materials are urgently needed to improve the service life of hydraulic machinery.Eutectic high entropy alloy(EHEA)is a new kind of alloys with in situ lamellar structure.NiCoCrFeNb0.45 EHEA has combined excellent strength and toughness.In this study,slurry erosion tests of NiCoCrFeNb0.45 EHEA were carried out with different impact angles and impact velocities using a rotary jet erosion test apparatus.The NiCoCrFeNb0.45EHEA exhibited significant slurry erosion resistance compared with medium carbon steel 1045 and stainless steel 04 Cr13 Ni5 Mo.The erosion rate of EHEA is much slower.Compared with medium carbon steel and stainless steel,the erosion of EHEA is completed via the accumulation and removal of platelets after plowing and work hardening,accompanied by partial micro-cutting.展开更多
The metal components exposed to the high-velocity liquid-solid flow can be rapidly eroded by the accelerated particles.With an excellent combination of strength and toughness,the NiCoCrFeNb_(0.45)eutectic high-entropy...The metal components exposed to the high-velocity liquid-solid flow can be rapidly eroded by the accelerated particles.With an excellent combination of strength and toughness,the NiCoCrFeNb_(0.45)eutectic high-entropy alloy(EHEA)has emerged as a promising material to resist erosion damage.In this study,the erosion behavior of NiCoCrFeNb_(0.45)EHEA in high-velocity multiphase flow is investigated through the coupling analysis of material properties,multiphase flow,and particle–surface impact behavior.The inherent mathematical relationship is discovered between the erosion rates and the impact velocity,impact angle,and test time.The results show that the NiCoCrFeNb_(0.45)EHEA has superior erosion resistance than the commonly used machinery materials.The principal material removal mechanism is the formation and brittle fracture of the platelets,accompanied by micro-cutting and ploughing at some oblique angles.The higher work-hardenability of NiCoCrFeNb_(0.45)EHEA could mitigate the erosion damage as time proceeds,and this effect becomes more apparent as the impact angle increases.Therefore,the evolution of erosion damage with time varies significantly depending on the impact angle.Based on the test data and computational fluid dynamics(CFD)modeling of the near-wall flow field,a power exponential function relationship between erosion depth and the corresponding impact velocity at various locations on the material surface is established.展开更多
Reaction infiltration instability(RII)can cause the formation of melt channels and potentially facilitate the physical transport of sulfide liquid,which contributes to the geochemical evolution of chalcophile elements...Reaction infiltration instability(RII)can cause the formation of melt channels and potentially facilitate the physical transport of sulfide liquid,which contributes to the geochemical evolution of chalcophile elements in the lithospheric mantle.This study conducted some two-layer reaction experiments to explore the feasibility of reaction-driven sulfide migration along high-velocity silicate-melt channels.With increasing duration,the formation of more silicate-melt channels and the transport of more sulfide droplets into a depleted peridotite were observed due to the increase of the local permeability.However,at a longer duration,the presence of some melt-channel relics implies that melt channels are temporary and ultimately closed when the reaction infiltration of silicate melt reached equilibrium in the depleted peridotite.Furthermore,theoretical calculations indicate that the RII of the system is suppressed,which impedes the formation of melt channels.The homogeneous distribution of silicate melt in a sulfide-free experiment implies that the Zener pinning of sulfide probably enhances the RII,thereby facilitating the formation of temporary melt channels.Therefore,this study demonstrates that sufficient silicate melt disequilibrium with solid phases in a liquid source potentially promotes the mechanical extraction of sulfides during reaction infiltration of silicate melt.展开更多
基金supported by the Natural Science Foundation of Jilin Province,No.2011146,2012150the Natural Science Foundation of Jilin Technology Division,No.201133139 and 201032235
文摘A survivin small interfering RNA sequence specific for a human and mouse homogenous sequence was constructed.Survivin small interfering RNA could significantly inhibit glioma cell proliferation and induce apoptosis when it was transfected into either a human glioma cell line U251 or rat glioma C6 cells in vitro.In addition,treatment of rat orthotopic glioma models with survivin small interfering demonstrated the inhibition of glioma growth in vivo.Our experimental findings suggest that the use of RNA interference techniques to target the survivin sequence may be useful in the treatment of glioma.
基金supported by the National Basic Research Program of China (973 Program) (2012CBA01200)Northern Rare Earth Science and Technology Project (BFXT-2015D-0002) and (2016H1928)
文摘The Bayan Obo deposit in northern China is an ultra-large Fe–REE–Nb deposit.The occurrences,and geochemical characteristics of thorium in iron ores from the Bayan Obo Main Ore Body were examined using chemical analysis,field emission scanning electron microscopy,energy dispersive spectrometer,and automatic mineral analysis software.Results identified that 91.69%of ThO2 in the combined samples was mainly distributed in rare earth minerals(bastnaesite,huanghoite,monazite;56.43%abundance in the samples),iron minerals(magnetite,hematite,pyrite;20.97%),niobium minerals(aeschynite;14.29%),and gangue minerals(aegirine,riebeckite,mica,dolomite,apatite,fluorite;4.22%).An unidentified portion(4.09%)of ThO2 may occur in other niobium minerals(niobite,ilmenorutile,pyrochlore).Only a few independent minerals of thorium occur in the iron ore samples.Thorium mainly occurs in rare earth minerals in the form of isomorphic substitution.Analyses of the geochemical characteristics of the major elements indicate that thorium mineralization in the Main Ore Body was related to alkali metasomatism,which provided source material and favorable porosity for hydrothermal mineralization.Trace elements such as Sc,Nb,Zr,and Ta have higher correlation coefficients with thorium,which resulted from being related to the relevant minerals formed during thorium mineralization.In addition,correlation analysis of ThO2 and TFe,and REO and TFe in the six types of iron ore samples showed that ThO2 did not always account for the highest distribution rate in rare earth minerals,and the main occurrence minerals of ThO2 were closely related to iron ore types.
基金Supported by Supported by the United Nations Environment Program(DXAL-2014-002)
文摘To understand the status of phytoplankton community of the Genhe River in the summer of 2015,we investigated the phytoplankton in Genhe River. We identified 5 phyla and 36 species,among which Bacillariophyta(23) were the most,followed by Chlorophyta(10),Cyanophyta(1),Chrysophyta(1),Pyrrophyta(1). The phytoplankton abundance was(15. 6-810) × 104 ind·L^(-1); the biomass was(0. 07-2. 876) mg·L-1; Shannon-wiener index was 1. 05-3. 24; Pielou evenness index was 0. 27-0. 96. Using Shannon-wiener index and Pielou index,the water quality of Genhe River was assessed,and the results showed that the water quality was the best at 5# sampling point,the water quality was good in 3#,4#,7#,8#,9# sampling points,and there was a state of pollution at other sampling points. Canonical correspondence analysis and Pearson correlation analysis showed that iron ion,transparency,p H value,water depth and water temperature were important environmental factors that affect the distribution of phytoplankton,and copper ion,nitrite ion and COD also significantly affected the distribution of phytoplankton.
基金the National Natural Science Foundation of China(No.51879216)Shaanxi Provincial Natural Science Foundation(No.2018JQ5152)。
文摘The flow passage components in hydraulic machinery will be eroded rapidly when running in sand water.The wear resistance of materials commonly used in hydraulic machinery needs to be improved to prevent the failure of hydraulic machinery.New wear-resistant materials are urgently needed to improve the service life of hydraulic machinery.Eutectic high entropy alloy(EHEA)is a new kind of alloys with in situ lamellar structure.NiCoCrFeNb0.45 EHEA has combined excellent strength and toughness.In this study,slurry erosion tests of NiCoCrFeNb0.45 EHEA were carried out with different impact angles and impact velocities using a rotary jet erosion test apparatus.The NiCoCrFeNb0.45EHEA exhibited significant slurry erosion resistance compared with medium carbon steel 1045 and stainless steel 04 Cr13 Ni5 Mo.The erosion rate of EHEA is much slower.Compared with medium carbon steel and stainless steel,the erosion of EHEA is completed via the accumulation and removal of platelets after plowing and work hardening,accompanied by partial micro-cutting.
基金supported by the National Natural Science Foundation of China(Nos.51906200,51879216)the Key Project of National Natural Science Foundation of China(No.51839010)+1 种基金the Key Laboratory Foundation of Education Department of Shaanxi(No.19JS045)the China Postdoctoral Science Foundation(Nos.2019TQ0248,2019M663735)。
文摘The metal components exposed to the high-velocity liquid-solid flow can be rapidly eroded by the accelerated particles.With an excellent combination of strength and toughness,the NiCoCrFeNb_(0.45)eutectic high-entropy alloy(EHEA)has emerged as a promising material to resist erosion damage.In this study,the erosion behavior of NiCoCrFeNb_(0.45)EHEA in high-velocity multiphase flow is investigated through the coupling analysis of material properties,multiphase flow,and particle–surface impact behavior.The inherent mathematical relationship is discovered between the erosion rates and the impact velocity,impact angle,and test time.The results show that the NiCoCrFeNb_(0.45)EHEA has superior erosion resistance than the commonly used machinery materials.The principal material removal mechanism is the formation and brittle fracture of the platelets,accompanied by micro-cutting and ploughing at some oblique angles.The higher work-hardenability of NiCoCrFeNb_(0.45)EHEA could mitigate the erosion damage as time proceeds,and this effect becomes more apparent as the impact angle increases.Therefore,the evolution of erosion damage with time varies significantly depending on the impact angle.Based on the test data and computational fluid dynamics(CFD)modeling of the near-wall flow field,a power exponential function relationship between erosion depth and the corresponding impact velocity at various locations on the material surface is established.
基金the National Natural Science Foundation of China(No.40172068).
文摘Reaction infiltration instability(RII)can cause the formation of melt channels and potentially facilitate the physical transport of sulfide liquid,which contributes to the geochemical evolution of chalcophile elements in the lithospheric mantle.This study conducted some two-layer reaction experiments to explore the feasibility of reaction-driven sulfide migration along high-velocity silicate-melt channels.With increasing duration,the formation of more silicate-melt channels and the transport of more sulfide droplets into a depleted peridotite were observed due to the increase of the local permeability.However,at a longer duration,the presence of some melt-channel relics implies that melt channels are temporary and ultimately closed when the reaction infiltration of silicate melt reached equilibrium in the depleted peridotite.Furthermore,theoretical calculations indicate that the RII of the system is suppressed,which impedes the formation of melt channels.The homogeneous distribution of silicate melt in a sulfide-free experiment implies that the Zener pinning of sulfide probably enhances the RII,thereby facilitating the formation of temporary melt channels.Therefore,this study demonstrates that sufficient silicate melt disequilibrium with solid phases in a liquid source potentially promotes the mechanical extraction of sulfides during reaction infiltration of silicate melt.
