The equiatomic and equimass TiHfMo,TiHfMoNb and TiHfMoNbZr alloys were prepared,and their microstructure,mechanical properties and bio-corrosion behaviors were systematically investigated.The results demonstrated that...The equiatomic and equimass TiHfMo,TiHfMoNb and TiHfMoNbZr alloys were prepared,and their microstructure,mechanical properties and bio-corrosion behaviors were systematically investigated.The results demonstrated that all the multi-principal element alloys(MPEAs)had a single BCC phase structure without any intermetallic compounds.Moreover,the Young’s moduli and hardness of the MPEAs were respectively within the range of 95−126 GPa and 5.5−6.4 GPa,respectively.In simulated body fluids,the MPEAs had excellent resistance to chloride ion attack due to the fact that the passive films consisted of multiple oxides and the surface possessed large contact angles.Compared with CP-Ti and Ti6Al4V alloy,equiatomic TiHfMo and TiHfMoNb alloys had a desirable combination of pitting and corrosion resistance,wettability,and wear resistance,and can be utilized as potential candidates for biomedical metallic implants.展开更多
The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evo...The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evolution of the coatings were analyzed. A multi-layered oxide scale formed due to the synergistic corrosion by H_(2)O and NaCl. The growth mechanism of the Co_(3)O_(4), Fe_(3)O_(4), Fe_(2)O3, CoFe_(2)O_(4), NiFe_(2)O_(4) and NiO in the scale was proposed according to the distribution of the CeO_(2) particles. Compared to Ni-Co cating, the Ni-Co-CeO_(2) coating exhibited superior corrosion resistance in the H_(2)O/NaCl steam, which is beacause the CeO_(2) exerted a blocking effect on retarding the diffusion of Fe atoms and corrosive medium, contributing to a reduced corrosion rate and an improved oxide adhesion compared to Ni-Co coating.展开更多
AIM To investigate the potential effect of curcumin on hepatitis B virus(HBV) covalently closed circular DNA(ccc DNA) and the underlying mechanism.METHODS A Hep G2.2.15 cell line stably transfected with HBV was treate...AIM To investigate the potential effect of curcumin on hepatitis B virus(HBV) covalently closed circular DNA(ccc DNA) and the underlying mechanism.METHODS A Hep G2.2.15 cell line stably transfected with HBV was treated with curcumin, and HBV surface antigen(HBs Ag) and e antigen(HBe Ag) expression levels were assessed by ELISA. Intracellular HBV DNA replication intermediates and ccc DNA were detected by Southern blot and real-time PCR, respectively. The acetylation levels of histones H3 and H4 were measured by Western blot. H3/H4-bound ccc DNA was detected by chromatin immunoprecipitation(Ch IP) assays. The deacetylase inhibitors trichostatin A and sodium butyrate were used to study the mechanism of action for curcumin. Additionally, short interfering RNAs(si RNAs) targeting HBV were tested along with curcumin.RESULTS Curcumin treatment led to time-and dose-dependent reductions in HBs Ag and HBe Ag expression and significant reductions in intracellular HBV DNA replication intermediates and HBV ccc DNA. After treatment with 20 μmol/L curcumin for 2 d, HBs Ag and ccc DNA levels in Hep G2.2.15 cells were reduced by up to 57.7%(P < 0.01) and 75.5%(P < 0.01), respectively, compared with levels in non-treated cells. Meanwhile, time-and dose-dependent reductions in the histone H3 acetylation levels were also detected upon treatment with curcumin, accompanied by reductions in H3-and H4-bound ccc DNA. Furthermore, the deacetylase inhibitors trichostatin A and sodium butyrate could block the effects of curcumin. Additionally, transfection of si RNAs targeting HBV enhanced the inhibitory effects of curcumin.CONCLUSION Curcumin inhibits HBV gene replication via downregulation of ccc DNA-bound histone acetylation and has the potential to be developed as a ccc DNA-targeting antiviral agent for hepatitis B.展开更多
Pt layers of 5 μm in thickness were electroplated before or after depositing NiCoCrAlY coating by arc ion plating(AIP) aiming for identifying the effect of Pt enriching position on microstructure and cyclic oxidation...Pt layers of 5 μm in thickness were electroplated before or after depositing NiCoCrAlY coating by arc ion plating(AIP) aiming for identifying the effect of Pt enriching position on microstructure and cyclic oxidation behavior of Pt modified NiCoCrAlY coatings. Al-rich zones formed at the same position of Ptrich zones for both modified coatings due to uphill diffusion of Al driven by Pt. Cyclic oxidation tests at 1000 and 1100?C indicated that oxidation resistance of NiCoCrAlY was improved by Pt modification via different mechanisms: at surface, Pt-rich zone promoted selective oxidation of Al to form α-Al_2O_3,whilst at coating/substrate interface Pt-rich zone acted as effective diffusion barrier for titanium. Roles of Pt played in enhancing the oxidation performance of various Pt-modified NiCoCrAlY coating were investigated.展开更多
Heavy metal-contaminated soil is one of the major environmental pollution problems of agricultural production and human health in the world.Remediation of heavy metals in soil is one of the most popular research subje...Heavy metal-contaminated soil is one of the major environmental pollution problems of agricultural production and human health in the world.Remediation of heavy metals in soil is one of the most popular research subjects.Different remediation strategies have been reported to remove heavy metals from contaminated soil,among which phytoremediation is the most important one.Compared with other major crops,cotton shows the strongest and most widespread resistance to abiotic stresses,such as heavy metals.Although heavy metal stress adversely affects the growth and development of cotton,cotton possesses a set of sophisticated stress-resistance strategies.As the main product of cotton is nonedible fibers,which have a large biomass and strong heavy metal absorption and enrichment capacities,cotton is an ideal crop to restore heavy metal-contaminated soils and has unique advantages in terms of both ecological and economic benefits,with great application prospects.In this review,based on domestic and foreign research results in recent years,the effects of heavy metals on cotton growth and product quality were analyzed,the heavy metal absorption,accumulation,translocation and enrichment characteristics of cotton plants were summarized,and the adaptation and tolerance mechanisms of cotton to heavy metals were explored.Furthermore,the view that cotton is an effective crop to remediate heavy metal pollution in farmland soil has been proposed,and popularization and application suggestions for planting cotton to repair heavy metal pollution have been put forward to provide a reference for the comprehensive evaluation of the economic feasibility of cotton to repair heavy metal pollution in farmland soil.展开更多
The endoscopy is the most direct and effective means for digestive tract diseases.Medical workers can conduct a series of manipulations with the help of endoscope,including checking,removing,stripping the diseased tis...The endoscopy is the most direct and effective means for digestive tract diseases.Medical workers can conduct a series of manipulations with the help of endoscope,including checking,removing,stripping the diseased tissue or placing the stent.In order to understand the frictional behaviour at the endoscope-oesophagus interface,the finite-element model was analysed by Abaqus in this study.Considering the different modelling conditions,the total force due to frictional stress,frictional dissipation and the maximum Mises stress for the whole model were studied.Results showed that with the increasing amplitude,coefficient of friction and decreasing diameter,the total forces due to the frictional stress and the FD increased obviously.It did not present a clear difference with the variable distance for overlapping parts(region L).The positions of maximum Mises stress for the whole model under different conditions mainly focused on the initial part of the region R.The maximum Mises stress between different diameters showed a big difference.The results can provide the basic data for the finite-element modelling of frictional behaviour of human tissue.展开更多
基金the financial supports from the National Key Research and Development Program of China(No.2022YFB3707501)the National Natural Science Foundation of China(No.51701083)+2 种基金GDAS’Project of Science and Technology Development,China(Nos.2022GDASZH-2022010103,2022GDASZH-2022010107,2020GDASYL-20200102030)the financial support from the National Natural Science Foundation of China(No.52001137)the Basic and Applied Basic Research Foundation of Guangzhou,China(No.202201010206)。
文摘The equiatomic and equimass TiHfMo,TiHfMoNb and TiHfMoNbZr alloys were prepared,and their microstructure,mechanical properties and bio-corrosion behaviors were systematically investigated.The results demonstrated that all the multi-principal element alloys(MPEAs)had a single BCC phase structure without any intermetallic compounds.Moreover,the Young’s moduli and hardness of the MPEAs were respectively within the range of 95−126 GPa and 5.5−6.4 GPa,respectively.In simulated body fluids,the MPEAs had excellent resistance to chloride ion attack due to the fact that the passive films consisted of multiple oxides and the surface possessed large contact angles.Compared with CP-Ti and Ti6Al4V alloy,equiatomic TiHfMo and TiHfMoNb alloys had a desirable combination of pitting and corrosion resistance,wettability,and wear resistance,and can be utilized as potential candidates for biomedical metallic implants.
基金supported by the National Key Research and Development Programme(2023YFB3408200)the National Nature Science Foundation of China(52201076 and 52471077)+2 种基金the Guangdong Provincial Key R&D Programme(2023B0909020002)the Guangdong Basic and Applied Basic Research Foundation(2021A1515111065,2021B1515120014 and 2022A1515010934)the Fundamental Research Funds for the Central Universities(21623216 and 11623216).
文摘The corrosion behavior of Ni-Co-CeO_(2) composite coating was investigated under a simulated high-temperature marine atmosphere alongside Ni-Co coating. The corrosion kinetics, phase composition and microstructure evolution of the coatings were analyzed. A multi-layered oxide scale formed due to the synergistic corrosion by H_(2)O and NaCl. The growth mechanism of the Co_(3)O_(4), Fe_(3)O_(4), Fe_(2)O3, CoFe_(2)O_(4), NiFe_(2)O_(4) and NiO in the scale was proposed according to the distribution of the CeO_(2) particles. Compared to Ni-Co cating, the Ni-Co-CeO_(2) coating exhibited superior corrosion resistance in the H_(2)O/NaCl steam, which is beacause the CeO_(2) exerted a blocking effect on retarding the diffusion of Fe atoms and corrosive medium, contributing to a reduced corrosion rate and an improved oxide adhesion compared to Ni-Co coating.
基金Supported by National Natural Science Foundation of China,No.81541140Natural Science Foundation of Hubei province of China,No.2014CFB645+2 种基金Research and Development project of the Science and Technology plan of Hubei province,No.2011BCB030Foundation for Innovative Research Teamof Hubei University of Medicine,No.2014CXG05Key program for precision Medicine of Taihe Hospital,No.2016JZ05
文摘AIM To investigate the potential effect of curcumin on hepatitis B virus(HBV) covalently closed circular DNA(ccc DNA) and the underlying mechanism.METHODS A Hep G2.2.15 cell line stably transfected with HBV was treated with curcumin, and HBV surface antigen(HBs Ag) and e antigen(HBe Ag) expression levels were assessed by ELISA. Intracellular HBV DNA replication intermediates and ccc DNA were detected by Southern blot and real-time PCR, respectively. The acetylation levels of histones H3 and H4 were measured by Western blot. H3/H4-bound ccc DNA was detected by chromatin immunoprecipitation(Ch IP) assays. The deacetylase inhibitors trichostatin A and sodium butyrate were used to study the mechanism of action for curcumin. Additionally, short interfering RNAs(si RNAs) targeting HBV were tested along with curcumin.RESULTS Curcumin treatment led to time-and dose-dependent reductions in HBs Ag and HBe Ag expression and significant reductions in intracellular HBV DNA replication intermediates and HBV ccc DNA. After treatment with 20 μmol/L curcumin for 2 d, HBs Ag and ccc DNA levels in Hep G2.2.15 cells were reduced by up to 57.7%(P < 0.01) and 75.5%(P < 0.01), respectively, compared with levels in non-treated cells. Meanwhile, time-and dose-dependent reductions in the histone H3 acetylation levels were also detected upon treatment with curcumin, accompanied by reductions in H3-and H4-bound ccc DNA. Furthermore, the deacetylase inhibitors trichostatin A and sodium butyrate could block the effects of curcumin. Additionally, transfection of si RNAs targeting HBV enhanced the inhibitory effects of curcumin.CONCLUSION Curcumin inhibits HBV gene replication via downregulation of ccc DNA-bound histone acetylation and has the potential to be developed as a ccc DNA-targeting antiviral agent for hepatitis B.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51671202 and 51301184)the Defense Industrial Technology Development Program (Grant No. JCKY2016404C001)sponsored by the "Guangdong Province Science and Technology Plan" (Grant No. 2017B090903005)
文摘Pt layers of 5 μm in thickness were electroplated before or after depositing NiCoCrAlY coating by arc ion plating(AIP) aiming for identifying the effect of Pt enriching position on microstructure and cyclic oxidation behavior of Pt modified NiCoCrAlY coatings. Al-rich zones formed at the same position of Ptrich zones for both modified coatings due to uphill diffusion of Al driven by Pt. Cyclic oxidation tests at 1000 and 1100?C indicated that oxidation resistance of NiCoCrAlY was improved by Pt modification via different mechanisms: at surface, Pt-rich zone promoted selective oxidation of Al to form α-Al_2O_3,whilst at coating/substrate interface Pt-rich zone acted as effective diffusion barrier for titanium. Roles of Pt played in enhancing the oxidation performance of various Pt-modified NiCoCrAlY coating were investigated.
基金The work supported by the funding from the National Natural Science Foundation of China(31960414)High-level Talent Fund of Scientific Research for Intrduction and Training in Yan'an,Shaanxi Province of China(2019-06)+3 种基金Specialized Research Fund for the Doctoral Program of Yan’an University(YDBK2017-35)Research Project of Yan’an University(YDZ2019-07,YDQ2019-26)Scientific Research Program Funded by Shaanxi Provincial Education Department(18JS116)Innovation and Entrepreneurship Training Program of Shaanxi Province(S201910719069,S202010719118).
文摘Heavy metal-contaminated soil is one of the major environmental pollution problems of agricultural production and human health in the world.Remediation of heavy metals in soil is one of the most popular research subjects.Different remediation strategies have been reported to remove heavy metals from contaminated soil,among which phytoremediation is the most important one.Compared with other major crops,cotton shows the strongest and most widespread resistance to abiotic stresses,such as heavy metals.Although heavy metal stress adversely affects the growth and development of cotton,cotton possesses a set of sophisticated stress-resistance strategies.As the main product of cotton is nonedible fibers,which have a large biomass and strong heavy metal absorption and enrichment capacities,cotton is an ideal crop to restore heavy metal-contaminated soils and has unique advantages in terms of both ecological and economic benefits,with great application prospects.In this review,based on domestic and foreign research results in recent years,the effects of heavy metals on cotton growth and product quality were analyzed,the heavy metal absorption,accumulation,translocation and enrichment characteristics of cotton plants were summarized,and the adaptation and tolerance mechanisms of cotton to heavy metals were explored.Furthermore,the view that cotton is an effective crop to remediate heavy metal pollution in farmland soil has been proposed,and popularization and application suggestions for planting cotton to repair heavy metal pollution have been put forward to provide a reference for the comprehensive evaluation of the economic feasibility of cotton to repair heavy metal pollution in farmland soil.
基金supported by the National Natural Science Foundation of China(nos.51675447).
文摘The endoscopy is the most direct and effective means for digestive tract diseases.Medical workers can conduct a series of manipulations with the help of endoscope,including checking,removing,stripping the diseased tissue or placing the stent.In order to understand the frictional behaviour at the endoscope-oesophagus interface,the finite-element model was analysed by Abaqus in this study.Considering the different modelling conditions,the total force due to frictional stress,frictional dissipation and the maximum Mises stress for the whole model were studied.Results showed that with the increasing amplitude,coefficient of friction and decreasing diameter,the total forces due to the frictional stress and the FD increased obviously.It did not present a clear difference with the variable distance for overlapping parts(region L).The positions of maximum Mises stress for the whole model under different conditions mainly focused on the initial part of the region R.The maximum Mises stress between different diameters showed a big difference.The results can provide the basic data for the finite-element modelling of frictional behaviour of human tissue.
