The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection functi...The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection function,which enables multiplex PCR reaction.In this study,this technique was used to establish triple dPCR detection for the genetically modified soybean MON87708 × MON89788 with stacked traits.Specific absolute quantitative detection was accomplished for the genomic DNA extracted from the homogenized seeds of GM stack MON87708× MON89788 soybean.Our results can serve as a reference for the absolute quantitative detection of stacked events of genetically modified crops.展开更多
In current electronic information era,the complex application circumstance of 5G devices pursues the exploration of multi-functional electromagnetic wave(EMW)absorbent materials and it has become the crucial focus in ...In current electronic information era,the complex application circumstance of 5G devices pursues the exploration of multi-functional electromagnetic wave(EMW)absorbent materials and it has become the crucial focus in industrial development.A two-dimensional(2D)graphite nanosheet decorated by nickel nanocapsules(2D graphite/Ni@C nanocomposite)was fabricated to possess the EMW absorption and the Escherichia coli(E.coli)anti-bacterial performance simultaneously.By adjusting the filling ratio and injecting nitrogen doping,the value of minimum reflection loss is−36.08 dB and the effective absorption bandwidth reaches to 5.12 GHz(from 11.4 to 16.52 GHz)with the mass ratio of 30 wt%and the absorber thickness of 2 mm.This 2D nanocomposite simultaneously gets an excellent anti-bacterial function expressing an E.coli anti-bacterial rate of 92%during 24 h which is significantly correlated to the interaction between the nanostructure of the 2D nanographite and the nickel ion released from Ni@C nanocapsules.This work provides a new approach to develop a promising 2D anti-bacterial EMW absorber.展开更多
The effect of copper addition to 2205 duplex stainless steel（DSS） on its resistance against pitting corrosion by the Pseudomonas aeruginosa biofilm was investigated using electrochemical and surface analysis techniq...The effect of copper addition to 2205 duplex stainless steel（DSS） on its resistance against pitting corrosion by the Pseudomonas aeruginosa biofilm was investigated using electrochemical and surface analysis techniques. Cu addition decreased the general corrosion resistance, resulting in a higher general corrosion rate in the sterile medium. Because DSS usually has a very small general corrosion rate, its pitting corrosion resistance is far more important. In this work, it was shown that 2205-3%Cu DSS exhibited a much higher pitting corrosion resistance against the P. aeruginosa biofilm compared with the 2205 DSS control, characterized by no significant change in the pitting potential and critical pitting temperature（CPT） values. The strong pitting resistance ability of 2205-3%Cu DSS could be attributed to the copper-rich phases on the surface and the release of copper ions, providing a strong antibacterial ability that inhibited the attachment and growth of the corrosive P. aeruginosa biofilm.展开更多
Microbiologically influenced corrosion(MIC) is a big threat to the strength and safety of many metallic materials used in different environments throughout the world. The metabolites and bioactivity of the microorgani...Microbiologically influenced corrosion(MIC) is a big threat to the strength and safety of many metallic materials used in different environments throughout the world. The metabolites and bioactivity of the microorganisms cause severe deterioration on the metals. In this study, MIC of pure titanium(Ti) was studied in the presence of a highly corrosive aerobic marine bacterium Pseudomonas aeruginosa. The results obtained from electrochemical test showed that Ti was corrosion resistant in the abiotic culture medium after 14 d, while the increased corrosion current density(i_(corr)) obtained from polarization curves and the decreased charge transfer resistance(R_(ct)) from electrochemical impedance spectroscopy(EIS)indicated the accelerated corrosion of Ti caused by P. aeruginosa biofilm. For further confirmation of the above results, the surface of Ti was investigated using scanning electron microscopy(SEM), confocal laser scanning microscopy(CLSM) and X-ray photoelectron spectroscopy(XPS). According to the XPS results, TiO_2 was formed in both abiotic and biotic conditions, while unstable oxide Ti_2O_3 was detected in the presence of P. aeruginosa, leading to the defects in the passive film and localized corrosion. Pitting corrosion was investigated with the help of CLSM, and the largest pit depth found on Ti surface immersed in P. aeruginosa was 1.2 μm. Ti was not immune to MIC caused by P. aeruginosa.展开更多
Microbiologically influenced corrosion(MIC) is becoming a serious problem for buried pipelines. Developing environmentally friendly strategies for MIC control is increasingly urgent in oil/gas pipeline industry.Copper...Microbiologically influenced corrosion(MIC) is becoming a serious problem for buried pipelines. Developing environmentally friendly strategies for MIC control is increasingly urgent in oil/gas pipeline industry.Copper(Cu) in steels can not only provide aging precipitation strengthening, but also kill bacterium,offering a special biofunction to steels. Based on the chemical composition of traditional X80 pipeline steel, two Cu-bearing pipeline steels(1% Cu and 2% Cu) were fabricated in this study. The microstructure,mechanical properties and antibacterial property against sulphate-reducing bacteria(SRB) and Pseudomonas aeruginosa(P. aeruginosa) were studied. It was found that the novel pipeline steel alloyed by 1%Cu exhibited acicular ferrite microstructure with nano-sized Cu-rich precipitates distribution in the matrix, resulting in better mechanical properties than the traditional X80 steel, and showed good MIC resistance as well. The pitting corrosion resistance of 1% Cu steel in as-aged condition was significantly better than that of X80 steel. A possible antibacterial mechanism of the Cu-bearing pipeline steel was proposed.展开更多
An antibacterial 2205-Cu duplex stainless steel （DSS） was shown to inhibit the formation and growth of corrosive marine biofilms by direct contact with copper-rich phases and the release of Cu^2＋ ions from the 2205...An antibacterial 2205-Cu duplex stainless steel （DSS） was shown to inhibit the formation and growth of corrosive marine biofilms by direct contact with copper-rich phases and the release of Cu^2＋ ions from the 2205-Cu DSS surface. In this work, the microbiologically influenced corrosion （MIC） resistance of 2205- Cu DS5 in the presence of the corrosive marine bacterium Pseudornonos aeruginosa was investigated. The addition of copper improved the mechanical properties such as the yield strength, the tensile strength and the hardness of 2205 DSS. Electrochemical test results from linear polarization resistance （LPR）, electrochemical impedance spectroscopy （EI5） and critical pitting temperature （CPT） measurements showed that 2205-Cu DSS possessed a larger polarization resistance （Rp）, charge transfer resistance （Rct） and CPT values, indicating the excellent MIC resistance of2205-Cu DSS against the corrosive P. aeruginosa biofilm. The live]dead staining results and the SEM images of biofilm confirmed the strong antibacterial ability of 2205-Cu DSS. The largest pit depth of 2205-Cu DSS was considerably smaller than that of 2205 DSS after 14d in the presence ofP. aeruginosa （2.2 μm vs 12.5 μm）. 2205-Cu DSS possessed a superior MIC resistance to regular 2205 DSS in the presence of aerobic P. aeruginosa.展开更多
The antibacterial Cu-bearing 304 L stainless steel is a new kind of structural and functional integrated metal material. In this work, evolution behavior of passive film of different heat treated Cu-bearing 304 L stai...The antibacterial Cu-bearing 304 L stainless steel is a new kind of structural and functional integrated metal material. In this work, evolution behavior of passive film of different heat treated Cu-bearing 304 L stainless steel immersed in 0.5 M H2SO4 solution was investigated by using electrochemical measurements, atomic force microscopy（AFM） observation and X-ray photoelectron spectroscopy（XPS） analysis.The results show that the solution and aging treated samples have the similar polarization behaviors. The passive film impedance experiences an initial decrease within 7 days followed by a subsequent increase,while the defect density of passive film presents the opposite trend. Meanwhile, the evolution of surface morphology and the estimated thickness of the passive film confirm that it experiences initial dissolution and follow-up repair. Furthermore, the Cr^3＋ content in passive film undergoes sequential reduction to increase, however the variation tendency of Cu^2＋ content is just opposite, indicating that the content variation of Cr and Cu in passive film reflects the competitive process of film dissolution and repair. In addition, compared with solution treated samples, aged samples have a bigger icorrvalue and the rougher passive film. This indicates that the passive film of solution treated steel is more compact and stable.展开更多
In this study,the CoCrW-x Cu alloys(x=2,3 and 4 wt%)were fabricated using selective laser melting(abbreviated as Co-2 Cu,Co-3 Cu and Co-4Cu)with the purpose of reducing the inflammation responses and the activity of o...In this study,the CoCrW-x Cu alloys(x=2,3 and 4 wt%)were fabricated using selective laser melting(abbreviated as Co-2 Cu,Co-3 Cu and Co-4Cu)with the purpose of reducing the inflammation responses and the activity of osteoclast.The metal ions releasing test showed that when the Cu content was less than 4 wt%,the releasing amount of Co and Cr ions was very small;however,when 4 wt%Cu was added in the CoCrW based alloy,the quantity of Co ions was significantly elevated with respect to the other groups due to the segregation of precipitates in the matrix;the Cu2+ion quantity of the Co-2Cu,Co-3Cu and Co-4Cu alloys were 0.05,0.09 and 0.27 g/(L cm2)after 7 d immersion,respectively;the RT-q PCR and ELISA data indicated that the expression levels of the pro-inflammatory cytokines(TNF-αand IL-6)were down-regulated in the Co-3Cu and Co-4Cu groups,whereas the expression level of the anti-inflammatory cytokine(IL-10)was up-regulated in all CoCrW-x Cu alloys;meanwhile,the Cu-containing CoCrW alloys significantly down-regulated the expression of the NF-B signal pathway in a Cu content-dependent manner,and the downstream transcription factors of NF-B signal pathway including NFATc1,TRAP and Cath-K were also down-regulated via potentially manipulating the NF-B signal pathway.After comprehensive consideration,it is considered that the Co-3Cu alloy is a potential material for self-alleviating inflammatory responses.展开更多
In the present study, a novel bacterium( Marinobacter aquaeolei) was examined for its corrosion inhibiting behaviour against X80 pipeline steel. Electrochemical results showed that X80 steel immersed in the solution i...In the present study, a novel bacterium( Marinobacter aquaeolei) was examined for its corrosion inhibiting behaviour against X80 pipeline steel. Electrochemical results showed that X80 steel immersed in the solution inoculated with M. aquaeolei possessed very high corrosion resistance compared to that of abiotic control. Besides, scanning electron microscopy, confocal laser scanning microscopy and energy-dispersive X-ray spectroscopy were employed to analyse the corrosion product and the biofi lm formed on the metal surface. Fourier-transform infrared spectroscopy was also applied to determine the composition of extracellular polymeric substances(EPS). Above results indicated that the corrosion inhibition effciency observed in biotic medium was very high(91%), proving that M. aquaeolei was an effective inhibitive agent for the corrosion of carbon steel. The inhibition was credited to the formation of bacterial biofi lm and the compact protective layer of the secreted EPS. Thus, this study will introduce a natural, environmentally friendly and cost-effective system for the corrosion control of the carbon steel.展开更多
Frequent food poisoning and food-borne diseases outbreaking in recent years have caused people to attach great attention to food safety,especially the food contact materials that are essential in the food industrial c...Frequent food poisoning and food-borne diseases outbreaking in recent years have caused people to attach great attention to food safety,especially the food contact materials that are essential in the food industrial chains and daily lives,ensuring their clean sanitation are of great importance in blocking microbial contamination and spread of food-borne pathogens.Stainless steel(SS)is one of the most accepted and widely used food contact material,and the Cu-bearing SS possesses excellent antibacterial performance and maintains the original mechanical properties of SS,maybe making it a better substitute for the conventional SS in the food area.Taking advantages of bactericidal and antifouling properties of Cubearing SS,this study simulated a variety of food contact scenarios,explored a new strategy for food preservation and food safety by using Cu-bearing SS as a food contact material.The results showed that the Cu-bearing SS could not only delay the spoilage of different foods by inhibiting the activity of microorganisms in foods,but also reduce the expressions of spoilage traits of bacteria as well as the formation of biofilms by quenching the quorum-sensing signals,and further creating a good bacteriostatic atmosphere for the contacted food and its surrounding environment.In addition,the remarkable antifouling property of Cu-bearing SS would give the material a self-cleaning feature for food applications,which can avoid secondary contamination of food as a source of contamination.This study well demonstrates that the Cu-bearing SS has broad application potentials and prospects in the food area.展开更多
S32654 super austenitic stainless steel（SASS） is widely used in highly corrosive environments. However,its microbiologically influenced corrosion（MIC） behavior has not been reported yet. In this study, the corrosi...S32654 super austenitic stainless steel（SASS） is widely used in highly corrosive environments. However,its microbiologically influenced corrosion（MIC） behavior has not been reported yet. In this study, the corrosion behavior of S32654 SASS caused by a corrosive marine bacterium Pseudomonas aeruginosa was investigated using electrochemical measurements and surface analysis techniques. It was found that P. aeruginosa biofilm accelerated the corrosion rate of S325654 SASS, which was demonstrated by a negative shift of the open circuit potential（EOCP）, a decrease of polarization resistance and an increase of corrosion current density in the culture medium. The largest pit depth of the coupons exposed in the P.aeruginosa broth for 14 days was 2.83 m, much deeper than that of the control（1.33 m） in the abiotic culture medium. It was likely that the P. aeruginosa biofilm catalyzed the formation of CrO_3, which was detrimental to the passive film, resulting in MIC pitting corrosion.展开更多
304 stainless steel(SS) used as orthodontic wire during orthodontics faces the risk of microbiologically influenced corrosion(MIC) due to diverse flora environment. Hereinto, Streptococcus mutans(S. mutans)is the most...304 stainless steel(SS) used as orthodontic wire during orthodontics faces the risk of microbiologically influenced corrosion(MIC) due to diverse flora environment. Hereinto, Streptococcus mutans(S. mutans)is the most important cariogenic bacteria. In this work, MIC behavior of a new 304-Cu SS in presence of S. mutans was studied by the observations using scanning electron microscopy(SEM) and confocal laser scanning microscopy(CLSM) including live/dead staining, extracellular polymeric substance(EPS)staining and pitting corrosion, electrochemical test, and X-ray photoelectron spectroscopy(XPS). Above results showed that 304-Cu SS possessed excellent biofilm inhibition ability and presented lower corrosion current density(icorr), larger polarization resistance(Rp) and charge transfer resistance(Rct) in the presence of S. mutans, indicating that 304-Cu SS had a better MIC resistance against S. mutans. It was further affirmed by XPS results that the presence of Cu-oxide in passive film of 304-Cu SS inhibited the formation of biofilm.展开更多
The coronavirus disease 2019(COVID-19)has spread globally.Although mixed liver impairment has been reported in COVID-19 patients,the association of liver injury caused by specific subtype especially chronic hepatitis ...The coronavirus disease 2019(COVID-19)has spread globally.Although mixed liver impairment has been reported in COVID-19 patients,the association of liver injury caused by specific subtype especially chronic hepatitis B(CHB)with COVID-19 has not been elucidated.In this multi-center,retrospective,and observational cohort study,109 CHB and 327 non-CHB patients with COVID-19 were propensity score matched at an approximate ratio of 3:1 on the basis of age,sex,and comorbidities.Demographic characteristics,laboratory examinations,disease severity,and clinical outcomes were compared.Furthermore,univariable and multivariable logistic and Cox regression models were used to explore the risk factors for disease severity and mortality,respectively.A higher proportion of CHB patients(30 of 109(27.52%))developed into severe status than non-CHB patients(17 of 327(5.20%)).In addition to previously reported liver impairment markers,such as alanine aminotransferase,aspartate aminotransferase,alkaline phosphatase,and total bilirubin,we identified several novel risk factors including elevated lactate dehydrogenase(≥245 U/L,hazard ratio(HR)=8.639,95%confidence interval(CI)=2.528–29.523;P<0.001)and coagulation-related biomarker D-dimer(≥0.5μg/mL,HR=4.321,95%CI=1.443–12.939;P=0.009)and decreased albumin(<35 g/L,HR=0.131,95%CI=0.048–0.361;P<0.001)and albumin/globulin ratio(<1.5,HR=0.123,95%CI=0.017–0.918;P=0.041).In conclusion,COVID-19 patients with CHB were more likely to develop into severe illness and die.The risk factors that we identified may be helpful for early clinical surveillance of critical progression.展开更多
1.Introduction Food spoilage microorganism results in food spoilage.They draw the nutrients from food to promote their own growth and re-production,so that the food lost original nutritional value,organi-zational char...1.Introduction Food spoilage microorganism results in food spoilage.They draw the nutrients from food to promote their own growth and re-production,so that the food lost original nutritional value,organi-zational characteristics and sensory quality.Here in,the most com-mon food spoilage is caused by bacteria and mold.Food spoilage not only deprives food edible value,but also poses serious major hazard threats to human health.Increase of the physical and chem-ical indexes of food caused by food spoilage can lead to occurrence of acute and chronic diseases in human and even death in severe cases[1,2].According to the data compiled by the World Food and Agriculture Organization(WFAO)in 2019,one third of food is lost globally each year,and the food spoilage caused by microorgan-isms is the main reason of the loss[3,4].Although food preserva-tion technology which can slow down the process of food spoilage has made rapid progress,improper food preservation method is still a common problem in the whole world.展开更多
文摘The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection function,which enables multiplex PCR reaction.In this study,this technique was used to establish triple dPCR detection for the genetically modified soybean MON87708 × MON89788 with stacked traits.Specific absolute quantitative detection was accomplished for the genomic DNA extracted from the homogenized seeds of GM stack MON87708× MON89788 soybean.Our results can serve as a reference for the absolute quantitative detection of stacked events of genetically modified crops.
基金This work was supported by the National Natural Science Foundation of China(Nos.51871219,52071324,52031014 and U1908220)the National Key R&D Program of China(Nos.2022YFB3504804 and 2021YFC2202402)the Bintech‐IMR R&D Program(GYY‐JSBU‐2022-007).
文摘In current electronic information era,the complex application circumstance of 5G devices pursues the exploration of multi-functional electromagnetic wave(EMW)absorbent materials and it has become the crucial focus in industrial development.A two-dimensional(2D)graphite nanosheet decorated by nickel nanocapsules(2D graphite/Ni@C nanocomposite)was fabricated to possess the EMW absorption and the Escherichia coli(E.coli)anti-bacterial performance simultaneously.By adjusting the filling ratio and injecting nitrogen doping,the value of minimum reflection loss is−36.08 dB and the effective absorption bandwidth reaches to 5.12 GHz(from 11.4 to 16.52 GHz)with the mass ratio of 30 wt%and the absorber thickness of 2 mm.This 2D nanocomposite simultaneously gets an excellent anti-bacterial function expressing an E.coli anti-bacterial rate of 92%during 24 h which is significantly correlated to the interaction between the nanostructure of the 2D nanographite and the nickel ion released from Ni@C nanocapsules.This work provides a new approach to develop a promising 2D anti-bacterial EMW absorber.
基金support of the program of Outstanding Young Scholars, the National Natural Science Foundation of China (No. 51371182)financially supported by Shenzhen Science and Technology Research funding (JCYJ20160608153641020)+3 种基金the National Basic Research Program of China (973 Program Project No. 2014CB643300)the National Natural Science Foundation (No. 51501203 and U1660118)the National Environmental Corrosion Platform (NECP)the “Young Merit Scholars” program of the Institute of Metal Research, Chinese Academy of Sciences
文摘The effect of copper addition to 2205 duplex stainless steel（DSS） on its resistance against pitting corrosion by the Pseudomonas aeruginosa biofilm was investigated using electrochemical and surface analysis techniques. Cu addition decreased the general corrosion resistance, resulting in a higher general corrosion rate in the sterile medium. Because DSS usually has a very small general corrosion rate, its pitting corrosion resistance is far more important. In this work, it was shown that 2205-3%Cu DSS exhibited a much higher pitting corrosion resistance against the P. aeruginosa biofilm compared with the 2205 DSS control, characterized by no significant change in the pitting potential and critical pitting temperature（CPT） values. The strong pitting resistance ability of 2205-3%Cu DSS could be attributed to the copper-rich phases on the surface and the release of copper ions, providing a strong antibacterial ability that inhibited the attachment and growth of the corrosive P. aeruginosa biofilm.
基金supportedfinancially by the National Natural Science Foundation of China(No.U1660118)the National Basic Research Program of China(No.2014CB643300)the National Environmental Corrosion Platform(NECP)
文摘Microbiologically influenced corrosion(MIC) is a big threat to the strength and safety of many metallic materials used in different environments throughout the world. The metabolites and bioactivity of the microorganisms cause severe deterioration on the metals. In this study, MIC of pure titanium(Ti) was studied in the presence of a highly corrosive aerobic marine bacterium Pseudomonas aeruginosa. The results obtained from electrochemical test showed that Ti was corrosion resistant in the abiotic culture medium after 14 d, while the increased corrosion current density(i_(corr)) obtained from polarization curves and the decreased charge transfer resistance(R_(ct)) from electrochemical impedance spectroscopy(EIS)indicated the accelerated corrosion of Ti caused by P. aeruginosa biofilm. For further confirmation of the above results, the surface of Ti was investigated using scanning electron microscopy(SEM), confocal laser scanning microscopy(CLSM) and X-ray photoelectron spectroscopy(XPS). According to the XPS results, TiO_2 was formed in both abiotic and biotic conditions, while unstable oxide Ti_2O_3 was detected in the presence of P. aeruginosa, leading to the defects in the passive film and localized corrosion. Pitting corrosion was investigated with the help of CLSM, and the largest pit depth found on Ti surface immersed in P. aeruginosa was 1.2 μm. Ti was not immune to MIC caused by P. aeruginosa.
基金supported financially by the Shenyang Science and Technology Research Funding(No.18-013-0-53)the Shenzhen Science and Technology Research Funding(No.JCYJ20160608153641020)
文摘Microbiologically influenced corrosion(MIC) is becoming a serious problem for buried pipelines. Developing environmentally friendly strategies for MIC control is increasingly urgent in oil/gas pipeline industry.Copper(Cu) in steels can not only provide aging precipitation strengthening, but also kill bacterium,offering a special biofunction to steels. Based on the chemical composition of traditional X80 pipeline steel, two Cu-bearing pipeline steels(1% Cu and 2% Cu) were fabricated in this study. The microstructure,mechanical properties and antibacterial property against sulphate-reducing bacteria(SRB) and Pseudomonas aeruginosa(P. aeruginosa) were studied. It was found that the novel pipeline steel alloyed by 1%Cu exhibited acicular ferrite microstructure with nano-sized Cu-rich precipitates distribution in the matrix, resulting in better mechanical properties than the traditional X80 steel, and showed good MIC resistance as well. The pitting corrosion resistance of 1% Cu steel in as-aged condition was significantly better than that of X80 steel. A possible antibacterial mechanism of the Cu-bearing pipeline steel was proposed.
基金financially supported by the National Natural Science Foundation of China(Nos.51501203 and U1660118)Shenzhen Science and Technology Research Funding(No.JCYJ20160608153641020)+1 种基金the National Basic Research Program of China(No.2014CB643300)the National Environmental Corrosion Platform(NECP)
文摘An antibacterial 2205-Cu duplex stainless steel （DSS） was shown to inhibit the formation and growth of corrosive marine biofilms by direct contact with copper-rich phases and the release of Cu^2＋ ions from the 2205-Cu DSS surface. In this work, the microbiologically influenced corrosion （MIC） resistance of 2205- Cu DS5 in the presence of the corrosive marine bacterium Pseudornonos aeruginosa was investigated. The addition of copper improved the mechanical properties such as the yield strength, the tensile strength and the hardness of 2205 DSS. Electrochemical test results from linear polarization resistance （LPR）, electrochemical impedance spectroscopy （EI5） and critical pitting temperature （CPT） measurements showed that 2205-Cu DSS possessed a larger polarization resistance （Rp）, charge transfer resistance （Rct） and CPT values, indicating the excellent MIC resistance of2205-Cu DSS against the corrosive P. aeruginosa biofilm. The live]dead staining results and the SEM images of biofilm confirmed the strong antibacterial ability of 2205-Cu DSS. The largest pit depth of 2205-Cu DSS was considerably smaller than that of 2205 DSS after 14d in the presence ofP. aeruginosa （2.2 μm vs 12.5 μm）. 2205-Cu DSS possessed a superior MIC resistance to regular 2205 DSS in the presence of aerobic P. aeruginosa.
基金supported by the National Key Research and Development Program of China (Grant No. 2016YFB0300205)the National Natural Science Foundation of China (Grant Nos. 51501188, 51771199 and 51371168)the State Key Program of National Natural Science of China (Grant No. 51631009)
文摘The antibacterial Cu-bearing 304 L stainless steel is a new kind of structural and functional integrated metal material. In this work, evolution behavior of passive film of different heat treated Cu-bearing 304 L stainless steel immersed in 0.5 M H2SO4 solution was investigated by using electrochemical measurements, atomic force microscopy（AFM） observation and X-ray photoelectron spectroscopy（XPS） analysis.The results show that the solution and aging treated samples have the similar polarization behaviors. The passive film impedance experiences an initial decrease within 7 days followed by a subsequent increase,while the defect density of passive film presents the opposite trend. Meanwhile, the evolution of surface morphology and the estimated thickness of the passive film confirm that it experiences initial dissolution and follow-up repair. Furthermore, the Cr^3＋ content in passive film undergoes sequential reduction to increase, however the variation tendency of Cu^2＋ content is just opposite, indicating that the content variation of Cr and Cu in passive film reflects the competitive process of film dissolution and repair. In addition, compared with solution treated samples, aged samples have a bigger icorrvalue and the rougher passive film. This indicates that the passive film of solution treated steel is more compact and stable.
基金financially supported by the National Natural Science Foundation of China(No.51801198)the National Key R&D Plan(No.2016YFC1100502).
文摘In this study,the CoCrW-x Cu alloys(x=2,3 and 4 wt%)were fabricated using selective laser melting(abbreviated as Co-2 Cu,Co-3 Cu and Co-4Cu)with the purpose of reducing the inflammation responses and the activity of osteoclast.The metal ions releasing test showed that when the Cu content was less than 4 wt%,the releasing amount of Co and Cr ions was very small;however,when 4 wt%Cu was added in the CoCrW based alloy,the quantity of Co ions was significantly elevated with respect to the other groups due to the segregation of precipitates in the matrix;the Cu2+ion quantity of the Co-2Cu,Co-3Cu and Co-4Cu alloys were 0.05,0.09 and 0.27 g/(L cm2)after 7 d immersion,respectively;the RT-q PCR and ELISA data indicated that the expression levels of the pro-inflammatory cytokines(TNF-αand IL-6)were down-regulated in the Co-3Cu and Co-4Cu groups,whereas the expression level of the anti-inflammatory cytokine(IL-10)was up-regulated in all CoCrW-x Cu alloys;meanwhile,the Cu-containing CoCrW alloys significantly down-regulated the expression of the NF-B signal pathway in a Cu content-dependent manner,and the downstream transcription factors of NF-B signal pathway including NFATc1,TRAP and Cath-K were also down-regulated via potentially manipulating the NF-B signal pathway.After comprehensive consideration,it is considered that the Co-3Cu alloy is a potential material for self-alleviating inflammatory responses.
基金Financial support was provided by the Shenzhen Science and Technology Research Funding (Grant No. JCY20160608153641020)the National Natural Science Foundation of China (Grant Nos. 51771199 and 51501188)+1 种基金the National Basic Research Program of China (Grant No. 2016YFB0300205)the State Key Program of National Natural Science of China (Grant No. 51631009)
文摘In the present study, a novel bacterium( Marinobacter aquaeolei) was examined for its corrosion inhibiting behaviour against X80 pipeline steel. Electrochemical results showed that X80 steel immersed in the solution inoculated with M. aquaeolei possessed very high corrosion resistance compared to that of abiotic control. Besides, scanning electron microscopy, confocal laser scanning microscopy and energy-dispersive X-ray spectroscopy were employed to analyse the corrosion product and the biofi lm formed on the metal surface. Fourier-transform infrared spectroscopy was also applied to determine the composition of extracellular polymeric substances(EPS). Above results indicated that the corrosion inhibition effciency observed in biotic medium was very high(91%), proving that M. aquaeolei was an effective inhibitive agent for the corrosion of carbon steel. The inhibition was credited to the formation of bacterial biofi lm and the compact protective layer of the secreted EPS. Thus, this study will introduce a natural, environmentally friendly and cost-effective system for the corrosion control of the carbon steel.
基金financially supported by the National Natural Science Foundation of China(Nos.51631009 and 51771199)the National Key Research and Development Program of China(No.2016YFB0300205)+1 种基金the Foshan Science and Technology Program(No.2017AG100041)Youth Innovation Promotion Association(No.2018221)。
文摘Frequent food poisoning and food-borne diseases outbreaking in recent years have caused people to attach great attention to food safety,especially the food contact materials that are essential in the food industrial chains and daily lives,ensuring their clean sanitation are of great importance in blocking microbial contamination and spread of food-borne pathogens.Stainless steel(SS)is one of the most accepted and widely used food contact material,and the Cu-bearing SS possesses excellent antibacterial performance and maintains the original mechanical properties of SS,maybe making it a better substitute for the conventional SS in the food area.Taking advantages of bactericidal and antifouling properties of Cubearing SS,this study simulated a variety of food contact scenarios,explored a new strategy for food preservation and food safety by using Cu-bearing SS as a food contact material.The results showed that the Cu-bearing SS could not only delay the spoilage of different foods by inhibiting the activity of microorganisms in foods,but also reduce the expressions of spoilage traits of bacteria as well as the formation of biofilms by quenching the quorum-sensing signals,and further creating a good bacteriostatic atmosphere for the contacted food and its surrounding environment.In addition,the remarkable antifouling property of Cu-bearing SS would give the material a self-cleaning feature for food applications,which can avoid secondary contamination of food as a source of contamination.This study well demonstrates that the Cu-bearing SS has broad application potentials and prospects in the food area.
基金financially supported by the High Technology Research and Development Program of China(No.2015AA034301)the National Natural Science Foundation of China(Grant Nos.51304041 and U1660118)Fundamental Research Funds for the Central Universities(Grant No.N150204007)
文摘S32654 super austenitic stainless steel（SASS） is widely used in highly corrosive environments. However,its microbiologically influenced corrosion（MIC） behavior has not been reported yet. In this study, the corrosion behavior of S32654 SASS caused by a corrosive marine bacterium Pseudomonas aeruginosa was investigated using electrochemical measurements and surface analysis techniques. It was found that P. aeruginosa biofilm accelerated the corrosion rate of S325654 SASS, which was demonstrated by a negative shift of the open circuit potential（EOCP）, a decrease of polarization resistance and an increase of corrosion current density in the culture medium. The largest pit depth of the coupons exposed in the P.aeruginosa broth for 14 days was 2.83 m, much deeper than that of the control（1.33 m） in the abiotic culture medium. It was likely that the P. aeruginosa biofilm catalyzed the formation of CrO_3, which was detrimental to the passive film, resulting in MIC pitting corrosion.
基金supported financially by the National Natural Science Foundation of China (Nos. 51501199, 51631009 and U1906226)the National Key Research and Development Program of China (No. 2016YFB0300205)。
文摘304 stainless steel(SS) used as orthodontic wire during orthodontics faces the risk of microbiologically influenced corrosion(MIC) due to diverse flora environment. Hereinto, Streptococcus mutans(S. mutans)is the most important cariogenic bacteria. In this work, MIC behavior of a new 304-Cu SS in presence of S. mutans was studied by the observations using scanning electron microscopy(SEM) and confocal laser scanning microscopy(CLSM) including live/dead staining, extracellular polymeric substance(EPS)staining and pitting corrosion, electrochemical test, and X-ray photoelectron spectroscopy(XPS). Above results showed that 304-Cu SS possessed excellent biofilm inhibition ability and presented lower corrosion current density(icorr), larger polarization resistance(Rp) and charge transfer resistance(Rct) in the presence of S. mutans, indicating that 304-Cu SS had a better MIC resistance against S. mutans. It was further affirmed by XPS results that the presence of Cu-oxide in passive film of 304-Cu SS inhibited the formation of biofilm.
基金supported by the National Natural Science Foundation of China(No.81974400)Natural Science Foundation of Zhuhai(No.ZH22036302200081-PWC to Renli Deng).
文摘The coronavirus disease 2019(COVID-19)has spread globally.Although mixed liver impairment has been reported in COVID-19 patients,the association of liver injury caused by specific subtype especially chronic hepatitis B(CHB)with COVID-19 has not been elucidated.In this multi-center,retrospective,and observational cohort study,109 CHB and 327 non-CHB patients with COVID-19 were propensity score matched at an approximate ratio of 3:1 on the basis of age,sex,and comorbidities.Demographic characteristics,laboratory examinations,disease severity,and clinical outcomes were compared.Furthermore,univariable and multivariable logistic and Cox regression models were used to explore the risk factors for disease severity and mortality,respectively.A higher proportion of CHB patients(30 of 109(27.52%))developed into severe status than non-CHB patients(17 of 327(5.20%)).In addition to previously reported liver impairment markers,such as alanine aminotransferase,aspartate aminotransferase,alkaline phosphatase,and total bilirubin,we identified several novel risk factors including elevated lactate dehydrogenase(≥245 U/L,hazard ratio(HR)=8.639,95%confidence interval(CI)=2.528–29.523;P<0.001)and coagulation-related biomarker D-dimer(≥0.5μg/mL,HR=4.321,95%CI=1.443–12.939;P=0.009)and decreased albumin(<35 g/L,HR=0.131,95%CI=0.048–0.361;P<0.001)and albumin/globulin ratio(<1.5,HR=0.123,95%CI=0.017–0.918;P=0.041).In conclusion,COVID-19 patients with CHB were more likely to develop into severe illness and die.The risk factors that we identified may be helpful for early clinical surveillance of critical progression.
基金supported by the National Key Research and Development Program of China (No. 2016YFB0300205)the National Natural Science Foundation of China (No. 51771199)+1 种基金the Youth Innovation Promotion Association CAS (No. 2018221)Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences
文摘1.Introduction Food spoilage microorganism results in food spoilage.They draw the nutrients from food to promote their own growth and re-production,so that the food lost original nutritional value,organi-zational characteristics and sensory quality.Here in,the most com-mon food spoilage is caused by bacteria and mold.Food spoilage not only deprives food edible value,but also poses serious major hazard threats to human health.Increase of the physical and chem-ical indexes of food caused by food spoilage can lead to occurrence of acute and chronic diseases in human and even death in severe cases[1,2].According to the data compiled by the World Food and Agriculture Organization(WFAO)in 2019,one third of food is lost globally each year,and the food spoilage caused by microorgan-isms is the main reason of the loss[3,4].Although food preserva-tion technology which can slow down the process of food spoilage has made rapid progress,improper food preservation method is still a common problem in the whole world.
