Objective: To analyze the role and influence of the GINS4 gene in breast cancer progression and to explore its expression in triple-negative and non-triple-negative breast cancer cell lines. Methods: Single-gene analy...Objective: To analyze the role and influence of the GINS4 gene in breast cancer progression and to explore its expression in triple-negative and non-triple-negative breast cancer cell lines. Methods: Single-gene analysis of GINS4 was performed by breast cancer RNA transcriptome data from The Cancer Genome Atlas (TCGA). Real-time quantitative polymerase chain reaction (PCR) was used to detect the expression of GINS4 in triple-negative and non-triple-negative breast cancer cell lines. The knockdown effects of GINS4 in MDA-MB-231 and MCF-7 cell lines on the proliferation and invasion of breast cancer cells were examined by cell counting kit 8 (CCK8) and Transwell assays. Results: Bioinformatics analysis showed that the expression of GINS4 in breast cancer was significantly higher than that in normal breast tissues (P > 0.05). At the same time, cell experiments confirmed that GINS4 was highly expressed in human breast cancer cell lines with normal breast cells as reference and in MDA-MB-231 and MCF-7 cell lines as reference, where the ability of proliferation and invasion of MDA-MB-231 and MCF-7 cells decreased after GINS4 knockdown. Conclusion: GINS4 is a gene associated with breast cancer malignancy, which can act as a novel tumor marker and has the potential as a new therapeutic target for breast cancer.展开更多
Humic acid is an important pool of heavy metals in sediments. Generally, the presence of refractory humic matter in aquatic systems would decrease the bioavailability of Cd and hence control the bioaccumulation of Cd ...Humic acid is an important pool of heavy metals in sediments. Generally, the presence of refractory humic matter in aquatic systems would decrease the bioavailability of Cd and hence control the bioaccumulation of Cd in benthic animals. In the present work, we applied a suspending system to determine the relative importance of particulate and dissolved fractions of humic acid as Cd sources for the bivalve Meretrix meretrix and to investigate the difference of bioaccumulation characteristics of Cd adsorbed on different fractions of humic acid. The results showed that.the bioaccumulation characteristics of Cd from particulate and dissolved fractions of humic acid were apparently different due to biological responses of the clam to the particulates. At Cd concentration of 140 mg/kg, the accumulation of Cd from Cd associated with humic acid mixtures was mainly attributed to the dissolved fractions of humic acid. Compared to particulate fractions, Cd associated with the dissolved fractions of humic acid may be more bioavailable.展开更多
An advanced cost-saving method of removal of high-As(Ⅲ)from SO_(4)(-Ⅱ)-rich metallurgical wastewater has been developed by diluting the SO_(4)(-Ⅱ)content with As(Ⅲ)-Cl(-Ⅰ)-rich metallurgical wastewater and then b...An advanced cost-saving method of removal of high-As(Ⅲ)from SO_(4)(-Ⅱ)-rich metallurgical wastewater has been developed by diluting the SO_(4)(-Ⅱ)content with As(Ⅲ)-Cl(-Ⅰ)-rich metallurgical wastewater and then by the direct precipitation of As(Ⅲ)with Fe(Ⅲ)at pH 2.3.As(Ⅲ)removal at various SO_(4)(-Ⅱ)/Cl(-Ⅰ)molar ratios and temperatures was investigated.The results showed that 65.2–98.2%of As(Ⅲ)immobilization into solids occurred at the SO_(4)(-Ⅱ)/Cl(-I)molar ratios of 1:1–32 and 15–60℃in 3 days,which were far higher than those in aqueous sole SO4(-Ⅱ)or Cl(-Ⅰ)media at the equimolar SO_(4)(-Ⅱ)or Cl(-Ⅰ)and the same temperature.SO_(4)(-Ⅱ)/Cl(-Ⅰ)molar ratio of 1:4 and 25℃were optimal conditions to reach the As removal maximum.Mixed aqueous SO4(-Ⅱ)and Cl(-Ⅰ)played a synergetic role in the main tooeleite formation together with(Cl(-Ⅰ)-free)ferric arsenite hydroxychloride(FAHC)involving the substitution of AsO_(3)^(3−)for Cl(-Ⅰ)for enhanced As fixation.The competitive complexation among FeH_(2)AsO_(3)^(2+),FeSO_(4)^(+)and FeCl^(2+)complexes was the main mechanism for the maximum As(Ⅲ)precipitation at the SO4(-Ⅱ)/Cl(-I)molar ratio of 1:4.Low As(Ⅲ)immobilization at high temperature with increased Fe(Ⅲ)hydrolysis was due to the formation of As(Ⅲ)-bearing ferrihydrite with the relatively high Fe/As molar ratio at acidic pH.展开更多
Sluggish kinetics of lithium/sulfur(Li/S)conversion chemistry and the ion channels formation in the cathode is still a bottleneck for developing future Li/S batteries with high-rate,long-cycling and high-energy.Here,a...Sluggish kinetics of lithium/sulfur(Li/S)conversion chemistry and the ion channels formation in the cathode is still a bottleneck for developing future Li/S batteries with high-rate,long-cycling and high-energy.Here,a rational cathode structure design of an oxygen(O)and nitrogen(N)tailoring carbon fiber aerogel(OCNF)as a host material integrated with platinum(Pt)electrocatalysis interface is employed to regulate Li/S conversion chemistry and ion channel.The Pt nanoparticles were uniformly sprayed onto the S surface to construct the electrocatalysis interface(Pt/S/OCNF)for generating ion channels to promote the effective penetration of electrolyte into the cathode.This Pt/S/OCNF gives the cathode a high sulfur utilization of 77.5%,an excellent rate capacity of 813.2 m Ah/g(2 C),and an outstanding long-cycling performance with a capacitance retention of 82.6%and a decay of 0.086%per cycle after 200 cycles at 0.5 C.Density functional theory(DFT)calculations reveal that the Pt electrocatalysis interface makes the cathode a high density of state(DOS)at Fermi level to facilitate the electrical conductivity,charge transfer kinetics and electrocatalysis to accelerate the lithium polysulfides(LiPSs)electrochemical conversion.Furthermore,the unique chemisorption structure and adsorption ability of Li2Sn(n=1,2,4,6,8)and S8on OCNF are attributed to the bridging effects of interfacial Pt and the bonding of N-Li.The Pt electrocatalysis interface combined with the unique 3D hierarchical porous structure and abundant functional active sites at OCNF guarantee strong adsorption confinement,fast Li/S electrocatalytic conversion and unblocked ion channels for electrolyte permeation in cathode.展开更多
The potential release capacity of arsenic(As)from sediment was evaluated under a high level of exogenous organic matter(EOM)with both bioreactive and chemically reactive organic matters(OMs).The OMs were characterized...The potential release capacity of arsenic(As)from sediment was evaluated under a high level of exogenous organic matter(EOM)with both bioreactive and chemically reactive organic matters(OMs).The OMs were characterized by FI,HIX,BIX,and SUVA254 fluorescence indices showing the biological activities were kept at a high level during the experimental period.At the genus level,Fe/Mn/As-reducing bacteria(Geobacter,Pseudomonas,Bacillus,and Clostridium)and bacteria(Paenibacillus,Acidovorax,Delftia,and Sphingomonas)that can participate in metabolic transformation using EOM were identified.The reducing condition occurs which promoted As,Fe,and Mn releases at very high concentrations of OM.However,As release increased during the first 15-20 days,followed by a decline contributed by secondary iron precipitation.The degree of As release may be limited by the reactivity of Fe(hydro)oxides.The EOM infiltration enhances As and Mn releases in aqueous conditions causing the risk of groundwater pollution,which could occur in specific sites such as landfills,petrochemical sites,and managed aquifer recharge projects.展开更多
It is well known that calcium arsenates may not be a good choice for arsenic removal and immobilization in hydrometallurgical practices.However,they are still produced at some plants in the world due to various reason...It is well known that calcium arsenates may not be a good choice for arsenic removal and immobilization in hydrometallurgical practices.However,they are still produced at some plants in the world due to various reasons.Furthermore,calcium arsenates can also naturally precipitate under some specific environments.However,the transformation process of poorly crystalline calcium arsenates(PCCA)and the stability of these samples under atmospheric CO2 are not yet well understood.This work investigated the transformation process of PCCA produced by using different neutralization reagents(CaO vs.NaOH)with various Ca/As molar ratios at pH 7-12 in the presence of atmospheric CO2.After aging at room temperature for a period of time,for samples neutralized with NaOH and precipitated at pH 10 and 12,release of arsenic back into the liquid phase occurred.In contrast,for the samples precipitated at pH 8,the aqueous concentration of arsenic was observed to decrease.XRD,Raman,and SEM results suggested that the formation of various types of crystalline calcium carbonates and/or calcium arsenates controls the arsenic behavior.Moreover,the application of lime may enhance the stability of the generated PCCA.However,no matter what neutralization reagent is used,the stability of the generated PCCA is still of concern.展开更多
The ubiquitous arsenic in groundwater poses a great risk to human health due to its environmental toxicity and carcinogenicity.In the present work,a new adsorbent,δ-MnO2 modified activated carbon,was prepared,and its...The ubiquitous arsenic in groundwater poses a great risk to human health due to its environmental toxicity and carcinogenicity.In the present work,a new adsorbent,δ-MnO2 modified activated carbon,was prepared,and its performance for the uptake of arsenate and arsenite species from aqueous solutions was investigated by batch experiments.Various techniques,including FESEM-EDX,p-XRD,XPS and BET surface area analysis,were employed to characterize the properties of the adsorbent and the arsenic adsorption mechanisms.The results showed thatδ-MnO2 covered on the surface and padded in the pores of the activated carbon.Adsorption kinetic studies revealed that approximately 90.1%and 76.8%of As(Ⅲ)and As(V),respectively,were removed by the adsorbent in the first 9 hr,and adsorption achieved equilibrium within 48 hr.The maximum adsorption capacities of As(V)and As(Ⅲ)at pH 4.0 calculated from Langmuir adsorption isotherms were 13.30 and 12.56 mg/g,respectively.The effect of pH on As(Ⅴ)and As(Ⅲ)removal was similar,and the removal efficiency significantly reduced with the increase of solution pH.Arsenite oxidation and adsorption kinetics showed that the As(Ⅴ)concentration in solution due to As(Ⅲ)oxidation and reductive dissolution of MnO2 increased rapidly during the first 12 min,and then gradually decreased.Based on the XPS analysis,nearly 93.3%of As(Ⅲ)had been oxidized to As(V)on the adsorbent surface and around 38.9%of Mn(Ⅳ)had been reduced to Mn(Ⅱ)after As(Ⅲ)adsorption.This approach provides a possible method for the purification of arsenic-contaminated groundwater.展开更多
Presented here is the influence of membrane pore size and dissolved organic matters on the diffusion coefficient（D） of aqueous arsenate, investigated by the diffusion cell method for the first time. The p H-dependen...Presented here is the influence of membrane pore size and dissolved organic matters on the diffusion coefficient（D） of aqueous arsenate, investigated by the diffusion cell method for the first time. The p H-dependent diffusion coefficient of arsenate was determined and compared with values from previous studies; the coefficient was found to decrease with increasing p H, showing the validity of our novel diffusion cell method. The D value increased dramatically as a function of membrane pore size at small pore sizes, and then increased slowly at pore sizes larger than 2.0 μm. Using the Exp Assoc model, the maximum D value was determined to be 11.2565 × 10^-6cm^2/sec. The presence of dissolved organic matters led to a dramatic increase of the D of arsenate, which could be attributed to electrostatic effects and ionic effects of salts. These results improve the understanding of the diffusion behavior of arsenate, especially the important role of various environmental parameters in the study and prediction of the migration of arsenate in aquatic water systems.展开更多
Tooeleite(Fe6(As03)4 SO4(OH)4·4 H2 O)is widely precipitated for direct As(III)removal from sulfate-rich industrial effluents.However,whether or not Fe(III)-As(III)-Cl(-I)precipitate is produced in chloridizing le...Tooeleite(Fe6(As03)4 SO4(OH)4·4 H2 O)is widely precipitated for direct As(III)removal from sulfate-rich industrial effluents.However,whether or not Fe(III)-As(III)-Cl(-I)precipitate is produced in chloridizing leaching media for As immobilization is almost unknown.This work founded the existence of ferric arsenite(hydroxy)chloride as a new mineral for As(III)removal.Its chemical composition and solid characterization were subsequently studied by using scanning electron microscope with an energy dispersive spectrometer(SEM-EDS),X-ray diffraction(XRD),infrared(FT-IR),Raman spectroscopy and thermogravimetric(TG)curve.The results showed the formation of a yellow precipitate after 3-days reaction of Fe(III)/As(III)with molar ratio≈1.7 in chloride solution at pH 2.3 neutralized with NaOH.Compared with tooeleite,chemical analysis and solid characterization indicated that Cl(-I)replaces S04(-II)producing ferric arsenite hydroxychloride with formula Fe5(As03)3-Cl2(OH)4·5 H2 O.This new plate shaped solid showed better crytallinity than tooeleite,although it has similar morphology and characteristic bands to tooeleite.The FT-IR bands at 628,964 cm-1 and the Raman bands at 448,610,961 cm-1 were assigned to Fe-O or As(Ⅲ)-O-Fe or As(Ⅲ)-O bending/stretching vibration,indicating that both arsenite and chloride substituted for the position of sulfate for ferric arsenite hydro xychloride produced due to the lack of the SO42-vibrations.Cl-(I)also contributed to increase As removal efficiency in aqueous sulfate media under acidic pH conditions via the probable formation of sulfatechloride ferric arsenite.展开更多
Mobilization of arsenic under anaerobic conditions is of great concern in arsenic contaminated soils and sediments. Bacterial reduction of As（V） and Fe（III） influences the cycling and partitioning of arsenic betwe...Mobilization of arsenic under anaerobic conditions is of great concern in arsenic contaminated soils and sediments. Bacterial reduction of As（V） and Fe（III） influences the cycling and partitioning of arsenic between solid and aqueous phase. We investigated the impact of bacterially mediated reductions of Fe（III）/Al hydroxides-bound arsenic（V） and iron（III） oxides on arsenic release. Our results suggested that As（V） reduction occurred prior to Fe（III） reduction, and Fe（III） reduction did not enhance the release of arsenic. Instead, Fe（III） hydroxides retained their dissolved concentrations during the experimental process, even though the new iron mineral-magnetite formed. In contrast, the release of reduced As（III） was promoted greatly when aluminum hydroxides was incorporated. Thus, the substitution of aluminum hydroxides may be responsible for the release of arsenic in the contaminated soils and sediments, since aluminum substitution of Fe（III） hydroxides universally occurs under natural conditions.展开更多
Mitochondrial calcium uniporter(MCU)has an important role in regulating mitochondrial calcium(Ca^(2+))homeostasis.Dysregulation of mitochondrial Ca^(2+)homeostasis has been implicated in various cancers.However,it rem...Mitochondrial calcium uniporter(MCU)has an important role in regulating mitochondrial calcium(Ca^(2+))homeostasis.Dysregulation of mitochondrial Ca^(2+)homeostasis has been implicated in various cancers.However,it remains unclear whether MCU regulates mitochondrial Ca^(2+)uptake to promote cell growth in colorectal cancer(CRC).Therefore,in the present study the expression of MCU in CRC tissues and its clinical significance were examined.Following which,the biological function of MCUmediated mitochondrial Ca^(2+)uptake in CRC cell growth and the underlying mechanisms were systematically evaluated using in in vitro and in vivo assays,which included western blotting,cell viability and apoptosis assays,as well as xenograft nude mice models.Our results demonstrated that MCU was markedly upregulated in CRC tissues at both the mRNA and protein levels.Upregulated MCU was associated with poor prognosis in patients with CRC.Our data reported that upregulation of MCU enhanced the mitochondrial Ca^(2+)uptake to promote mitochondrial biogenesis,which in turn facilitated CRC cell growth in vitro and in vivo.In terms of the underlying mechanism,it was identified that MCU-mediated mitochondrial Ca^(2+)uptake inhibited the phosphorylation of transcription factor A,mitochondrial(TFAM),and thus enhanced its stability to promote mitochondrial biogenesis.Furthermore,our data indicated that increased mitochondrial Ca^(2+)uptake led to increased mitochondrial production of ROS via the upregulation of mitochondrial biogenesis,which subsequently activated NF-κB signaling to accelerate CRC growth.In conclusion,the results indicated that MCU-induced mitochondrial Ca^(2+)uptake promotes mitochondrial biogenesis by suppressing phosphorylation of TFAM,thus contributing to CRC cell growth.Our findings reveal a novel mechanism underlying mitochondrial Ca^(2+)-mediated CRC cell growth and may provide a potential pharmacological target for CRC treatment.展开更多
文摘Objective: To analyze the role and influence of the GINS4 gene in breast cancer progression and to explore its expression in triple-negative and non-triple-negative breast cancer cell lines. Methods: Single-gene analysis of GINS4 was performed by breast cancer RNA transcriptome data from The Cancer Genome Atlas (TCGA). Real-time quantitative polymerase chain reaction (PCR) was used to detect the expression of GINS4 in triple-negative and non-triple-negative breast cancer cell lines. The knockdown effects of GINS4 in MDA-MB-231 and MCF-7 cell lines on the proliferation and invasion of breast cancer cells were examined by cell counting kit 8 (CCK8) and Transwell assays. Results: Bioinformatics analysis showed that the expression of GINS4 in breast cancer was significantly higher than that in normal breast tissues (P > 0.05). At the same time, cell experiments confirmed that GINS4 was highly expressed in human breast cancer cell lines with normal breast cells as reference and in MDA-MB-231 and MCF-7 cell lines as reference, where the ability of proliferation and invasion of MDA-MB-231 and MCF-7 cells decreased after GINS4 knockdown. Conclusion: GINS4 is a gene associated with breast cancer malignancy, which can act as a novel tumor marker and has the potential as a new therapeutic target for breast cancer.
基金supported by the Ministry of Science and Technology of China through the National Basic Research Program (973) of China (No.2009CB426301)the National Natural Science Foundation of China (No.40773076)
文摘Humic acid is an important pool of heavy metals in sediments. Generally, the presence of refractory humic matter in aquatic systems would decrease the bioavailability of Cd and hence control the bioaccumulation of Cd in benthic animals. In the present work, we applied a suspending system to determine the relative importance of particulate and dissolved fractions of humic acid as Cd sources for the bivalve Meretrix meretrix and to investigate the difference of bioaccumulation characteristics of Cd adsorbed on different fractions of humic acid. The results showed that.the bioaccumulation characteristics of Cd from particulate and dissolved fractions of humic acid were apparently different due to biological responses of the clam to the particulates. At Cd concentration of 140 mg/kg, the accumulation of Cd from Cd associated with humic acid mixtures was mainly attributed to the dissolved fractions of humic acid. Compared to particulate fractions, Cd associated with the dissolved fractions of humic acid may be more bioavailable.
基金supported by the National Key Research and Development Program of China (No.2019YFC1804400)the National Natural Science Foundation of China (Nos.41877393,41877379,42007364 and 42077309)+1 种基金Youth Innovation Promotion Association CAS (No.2021196)Liao Ning Revitalization Talents Program (Nos.XLYC1807185 and XLYC1807025)
文摘An advanced cost-saving method of removal of high-As(Ⅲ)from SO_(4)(-Ⅱ)-rich metallurgical wastewater has been developed by diluting the SO_(4)(-Ⅱ)content with As(Ⅲ)-Cl(-Ⅰ)-rich metallurgical wastewater and then by the direct precipitation of As(Ⅲ)with Fe(Ⅲ)at pH 2.3.As(Ⅲ)removal at various SO_(4)(-Ⅱ)/Cl(-Ⅰ)molar ratios and temperatures was investigated.The results showed that 65.2–98.2%of As(Ⅲ)immobilization into solids occurred at the SO_(4)(-Ⅱ)/Cl(-I)molar ratios of 1:1–32 and 15–60℃in 3 days,which were far higher than those in aqueous sole SO4(-Ⅱ)or Cl(-Ⅰ)media at the equimolar SO_(4)(-Ⅱ)or Cl(-Ⅰ)and the same temperature.SO_(4)(-Ⅱ)/Cl(-Ⅰ)molar ratio of 1:4 and 25℃were optimal conditions to reach the As removal maximum.Mixed aqueous SO4(-Ⅱ)and Cl(-Ⅰ)played a synergetic role in the main tooeleite formation together with(Cl(-Ⅰ)-free)ferric arsenite hydroxychloride(FAHC)involving the substitution of AsO_(3)^(3−)for Cl(-Ⅰ)for enhanced As fixation.The competitive complexation among FeH_(2)AsO_(3)^(2+),FeSO_(4)^(+)and FeCl^(2+)complexes was the main mechanism for the maximum As(Ⅲ)precipitation at the SO4(-Ⅱ)/Cl(-I)molar ratio of 1:4.Low As(Ⅲ)immobilization at high temperature with increased Fe(Ⅲ)hydrolysis was due to the formation of As(Ⅲ)-bearing ferrihydrite with the relatively high Fe/As molar ratio at acidic pH.
基金funding support from National Key R&D Program of China(No.2016YFB0100100)The National Natural Science Foundation of China(Nos.21961024,21961025,21433013,U1832218)+5 种基金Inner Mongolia Natural Science Foundation(No.2018JQ05)Supported by Incentive Funding from Nano Innovation Institute(NII)of Inner Mongolia University for Nationalities(IMUN)Inner Mongolia Autonomous Region Funding Project for Science&Technology Achievement Transformation(No.CGZH2018156)Inner Mongolia Autonomous Region Incentive Funding Guided Project for Science&Technology Innovation(2016)Inner Mongolia Autonomous Region Science&Technology Planning Project for Applied Technology Research and Development(No.2019GG261)Tongliao Funding Project for Application Technology Research&Development(2017)。
文摘Sluggish kinetics of lithium/sulfur(Li/S)conversion chemistry and the ion channels formation in the cathode is still a bottleneck for developing future Li/S batteries with high-rate,long-cycling and high-energy.Here,a rational cathode structure design of an oxygen(O)and nitrogen(N)tailoring carbon fiber aerogel(OCNF)as a host material integrated with platinum(Pt)electrocatalysis interface is employed to regulate Li/S conversion chemistry and ion channel.The Pt nanoparticles were uniformly sprayed onto the S surface to construct the electrocatalysis interface(Pt/S/OCNF)for generating ion channels to promote the effective penetration of electrolyte into the cathode.This Pt/S/OCNF gives the cathode a high sulfur utilization of 77.5%,an excellent rate capacity of 813.2 m Ah/g(2 C),and an outstanding long-cycling performance with a capacitance retention of 82.6%and a decay of 0.086%per cycle after 200 cycles at 0.5 C.Density functional theory(DFT)calculations reveal that the Pt electrocatalysis interface makes the cathode a high density of state(DOS)at Fermi level to facilitate the electrical conductivity,charge transfer kinetics and electrocatalysis to accelerate the lithium polysulfides(LiPSs)electrochemical conversion.Furthermore,the unique chemisorption structure and adsorption ability of Li2Sn(n=1,2,4,6,8)and S8on OCNF are attributed to the bridging effects of interfacial Pt and the bonding of N-Li.The Pt electrocatalysis interface combined with the unique 3D hierarchical porous structure and abundant functional active sites at OCNF guarantee strong adsorption confinement,fast Li/S electrocatalytic conversion and unblocked ion channels for electrolyte permeation in cathode.
基金supported by the National Key Research and Development Program(2019YFC1806204)the National Natural Science Foundation of China(No.41907178).
文摘The potential release capacity of arsenic(As)from sediment was evaluated under a high level of exogenous organic matter(EOM)with both bioreactive and chemically reactive organic matters(OMs).The OMs were characterized by FI,HIX,BIX,and SUVA254 fluorescence indices showing the biological activities were kept at a high level during the experimental period.At the genus level,Fe/Mn/As-reducing bacteria(Geobacter,Pseudomonas,Bacillus,and Clostridium)and bacteria(Paenibacillus,Acidovorax,Delftia,and Sphingomonas)that can participate in metabolic transformation using EOM were identified.The reducing condition occurs which promoted As,Fe,and Mn releases at very high concentrations of OM.However,As release increased during the first 15-20 days,followed by a decline contributed by secondary iron precipitation.The degree of As release may be limited by the reactivity of Fe(hydro)oxides.The EOM infiltration enhances As and Mn releases in aqueous conditions causing the risk of groundwater pollution,which could occur in specific sites such as landfills,petrochemical sites,and managed aquifer recharge projects.
基金supported by the National Natural Science Foundation of China (Nos. 41530643, 41673130 and 41877393)the National Key R&D Program of China (No. 2017YFD0800301)the Chinese Academy of Sciences (No. QYZDJ-SSW-DQC038)
文摘It is well known that calcium arsenates may not be a good choice for arsenic removal and immobilization in hydrometallurgical practices.However,they are still produced at some plants in the world due to various reasons.Furthermore,calcium arsenates can also naturally precipitate under some specific environments.However,the transformation process of poorly crystalline calcium arsenates(PCCA)and the stability of these samples under atmospheric CO2 are not yet well understood.This work investigated the transformation process of PCCA produced by using different neutralization reagents(CaO vs.NaOH)with various Ca/As molar ratios at pH 7-12 in the presence of atmospheric CO2.After aging at room temperature for a period of time,for samples neutralized with NaOH and precipitated at pH 10 and 12,release of arsenic back into the liquid phase occurred.In contrast,for the samples precipitated at pH 8,the aqueous concentration of arsenic was observed to decrease.XRD,Raman,and SEM results suggested that the formation of various types of crystalline calcium carbonates and/or calcium arsenates controls the arsenic behavior.Moreover,the application of lime may enhance the stability of the generated PCCA.However,no matter what neutralization reagent is used,the stability of the generated PCCA is still of concern.
基金This work was supported by the National Natural Science Foundation of China(Nos.41530643 and 41807358)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB14020203)the Joint Fund of NSFC and Henan(No.U1804110).
文摘The ubiquitous arsenic in groundwater poses a great risk to human health due to its environmental toxicity and carcinogenicity.In the present work,a new adsorbent,δ-MnO2 modified activated carbon,was prepared,and its performance for the uptake of arsenate and arsenite species from aqueous solutions was investigated by batch experiments.Various techniques,including FESEM-EDX,p-XRD,XPS and BET surface area analysis,were employed to characterize the properties of the adsorbent and the arsenic adsorption mechanisms.The results showed thatδ-MnO2 covered on the surface and padded in the pores of the activated carbon.Adsorption kinetic studies revealed that approximately 90.1%and 76.8%of As(Ⅲ)and As(V),respectively,were removed by the adsorbent in the first 9 hr,and adsorption achieved equilibrium within 48 hr.The maximum adsorption capacities of As(V)and As(Ⅲ)at pH 4.0 calculated from Langmuir adsorption isotherms were 13.30 and 12.56 mg/g,respectively.The effect of pH on As(Ⅴ)and As(Ⅲ)removal was similar,and the removal efficiency significantly reduced with the increase of solution pH.Arsenite oxidation and adsorption kinetics showed that the As(Ⅴ)concentration in solution due to As(Ⅲ)oxidation and reductive dissolution of MnO2 increased rapidly during the first 12 min,and then gradually decreased.Based on the XPS analysis,nearly 93.3%of As(Ⅲ)had been oxidized to As(V)on the adsorbent surface and around 38.9%of Mn(Ⅳ)had been reduced to Mn(Ⅱ)after As(Ⅲ)adsorption.This approach provides a possible method for the purification of arsenic-contaminated groundwater.
基金supported by the National Natural Science Foundation of China(Nos.41530643,41273133)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB14020203)
文摘Presented here is the influence of membrane pore size and dissolved organic matters on the diffusion coefficient（D） of aqueous arsenate, investigated by the diffusion cell method for the first time. The p H-dependent diffusion coefficient of arsenate was determined and compared with values from previous studies; the coefficient was found to decrease with increasing p H, showing the validity of our novel diffusion cell method. The D value increased dramatically as a function of membrane pore size at small pore sizes, and then increased slowly at pore sizes larger than 2.0 μm. Using the Exp Assoc model, the maximum D value was determined to be 11.2565 × 10^-6cm^2/sec. The presence of dissolved organic matters led to a dramatic increase of the D of arsenate, which could be attributed to electrostatic effects and ionic effects of salts. These results improve the understanding of the diffusion behavior of arsenate, especially the important role of various environmental parameters in the study and prediction of the migration of arsenate in aquatic water systems.
基金supported by the National Natural Science Foundation of China(Nos.41530643,41703133 and 41877393)the Chinese Academy of Sciences(No.QYZDJSSW-DQC038)the Liaoning Province Doctoral Scientific Research Initiation Fund Project(No.2019-BS-261)
文摘Tooeleite(Fe6(As03)4 SO4(OH)4·4 H2 O)is widely precipitated for direct As(III)removal from sulfate-rich industrial effluents.However,whether or not Fe(III)-As(III)-Cl(-I)precipitate is produced in chloridizing leaching media for As immobilization is almost unknown.This work founded the existence of ferric arsenite(hydroxy)chloride as a new mineral for As(III)removal.Its chemical composition and solid characterization were subsequently studied by using scanning electron microscope with an energy dispersive spectrometer(SEM-EDS),X-ray diffraction(XRD),infrared(FT-IR),Raman spectroscopy and thermogravimetric(TG)curve.The results showed the formation of a yellow precipitate after 3-days reaction of Fe(III)/As(III)with molar ratio≈1.7 in chloride solution at pH 2.3 neutralized with NaOH.Compared with tooeleite,chemical analysis and solid characterization indicated that Cl(-I)replaces S04(-II)producing ferric arsenite hydroxychloride with formula Fe5(As03)3-Cl2(OH)4·5 H2 O.This new plate shaped solid showed better crytallinity than tooeleite,although it has similar morphology and characteristic bands to tooeleite.The FT-IR bands at 628,964 cm-1 and the Raman bands at 448,610,961 cm-1 were assigned to Fe-O or As(Ⅲ)-O-Fe or As(Ⅲ)-O bending/stretching vibration,indicating that both arsenite and chloride substituted for the position of sulfate for ferric arsenite hydro xychloride produced due to the lack of the SO42-vibrations.Cl-(I)also contributed to increase As removal efficiency in aqueous sulfate media under acidic pH conditions via the probable formation of sulfatechloride ferric arsenite.
基金supported by the National Natural Science Foundation of China (No. 40925011)the Chinese Academy of Sciences (No. KZCX2-YW-446)
文摘Mobilization of arsenic under anaerobic conditions is of great concern in arsenic contaminated soils and sediments. Bacterial reduction of As（V） and Fe（III） influences the cycling and partitioning of arsenic between solid and aqueous phase. We investigated the impact of bacterially mediated reductions of Fe（III）/Al hydroxides-bound arsenic（V） and iron（III） oxides on arsenic release. Our results suggested that As（V） reduction occurred prior to Fe（III） reduction, and Fe（III） reduction did not enhance the release of arsenic. Instead, Fe（III） hydroxides retained their dissolved concentrations during the experimental process, even though the new iron mineral-magnetite formed. In contrast, the release of reduced As（III） was promoted greatly when aluminum hydroxides was incorporated. Thus, the substitution of aluminum hydroxides may be responsible for the release of arsenic in the contaminated soils and sediments, since aluminum substitution of Fe（III） hydroxides universally occurs under natural conditions.
基金supported by the National Natural Science Foundation of China(grants 81872302 and 81902513)Science and Technology Co-ordinate Innovation Project of Shaanxi Province,China(grants 2016TZC-S-18-1).
文摘Mitochondrial calcium uniporter(MCU)has an important role in regulating mitochondrial calcium(Ca^(2+))homeostasis.Dysregulation of mitochondrial Ca^(2+)homeostasis has been implicated in various cancers.However,it remains unclear whether MCU regulates mitochondrial Ca^(2+)uptake to promote cell growth in colorectal cancer(CRC).Therefore,in the present study the expression of MCU in CRC tissues and its clinical significance were examined.Following which,the biological function of MCUmediated mitochondrial Ca^(2+)uptake in CRC cell growth and the underlying mechanisms were systematically evaluated using in in vitro and in vivo assays,which included western blotting,cell viability and apoptosis assays,as well as xenograft nude mice models.Our results demonstrated that MCU was markedly upregulated in CRC tissues at both the mRNA and protein levels.Upregulated MCU was associated with poor prognosis in patients with CRC.Our data reported that upregulation of MCU enhanced the mitochondrial Ca^(2+)uptake to promote mitochondrial biogenesis,which in turn facilitated CRC cell growth in vitro and in vivo.In terms of the underlying mechanism,it was identified that MCU-mediated mitochondrial Ca^(2+)uptake inhibited the phosphorylation of transcription factor A,mitochondrial(TFAM),and thus enhanced its stability to promote mitochondrial biogenesis.Furthermore,our data indicated that increased mitochondrial Ca^(2+)uptake led to increased mitochondrial production of ROS via the upregulation of mitochondrial biogenesis,which subsequently activated NF-κB signaling to accelerate CRC growth.In conclusion,the results indicated that MCU-induced mitochondrial Ca^(2+)uptake promotes mitochondrial biogenesis by suppressing phosphorylation of TFAM,thus contributing to CRC cell growth.Our findings reveal a novel mechanism underlying mitochondrial Ca^(2+)-mediated CRC cell growth and may provide a potential pharmacological target for CRC treatment.
