Infections with multidrug-resistant(MDR)Gram-negative bacteria,such as MDR Escherichia coli(E.coli),remain a challenge due to the lack of safe antibiotics and high fatality rates under anti-infection therapies.This wo...Infections with multidrug-resistant(MDR)Gram-negative bacteria,such as MDR Escherichia coli(E.coli),remain a challenge due to the lack of safe antibiotics and high fatality rates under anti-infection therapies.This work presents a form of biomimetic intelligent catalysis inspired by the selective biocatalytic property of macrophages(MΦs),consisting of an intelligent controlling center(a living MΦ)and a Fenton reaction catalyst(Fe_(3)O_(4)@poly(lactic-co-glycolic acid)(PLGA)nanoparticles)for killing MDR E.coli without harming normal cells.The MΦ-Fe_(3)O_(4)@PLGA particles(i.e.,the intelligent catalysis particles)exhibit selective biocatalysis activity toward MDR E.coli by producing H_(2)O_(2) and lipid droplets(LDs).This process activates the lipid metabolism and glycan biosynthesis and metabolism pathways based on the result of RNA sequencing data analysis.The H_(2)O_(2) further reacts with Fe_(3)O_(4)@PLGA to form highly toxic hydroxyl radicals(·OH),while the LDs contain antimicrobial peptides and can target MDR E.coli.The highly toxicOH and antimicrobial peptides are shown to combat with MDR E.coli,such that the antibacterial efficiency of the MΦ-Fe_(3)O_(4)@PLGA particles against MDR E.coli is 99.29%±0.31%in vitro.More importantly,after several passages,the intelligent catalysis function of the MΦ-Fe_(3)O_(4)@PLGA particles is well maintained.Hence,the concept of biomimetic intelligent catalysts displays potential for treating diseases other than infections.展开更多
Fe_3O_4/Polystyrene(PSt) magnetic particles with core/shell structure have been prepared in thepresence of Fe_3O_4 magnetic fluid in ethanol/water medium by dispersion polymeriation of styrene. A Fe_3O_4particle forma...Fe_3O_4/Polystyrene(PSt) magnetic particles with core/shell structure have been prepared in thepresence of Fe_3O_4 magnetic fluid in ethanol/water medium by dispersion polymeriation of styrene. A Fe_3O_4particle formation mechanism was proposed. According to this mechanism, the size of particle nuclei isdetermined by the extent of aggregation of Fe_3O_4 /oligomer. Magnetic particles with diameter ranging from 5to 200 μm were prepared under different reaction conditions. Some polymerization parameters such as theconcentration of monomer, stabilizer, initiator, and ethanol which affect particle size and size distribution arediscussed and their effect on particle formation are explained by the proposed mechanism.展开更多
Fe3O4/P （NaUA-St-BA） core-shell composite micro spheres were in situ prepared by soapless polymerization of styrene and butyl acrylate, with Fe3O4magnetic colloidal particles coated with NaUA. The results of IR and ...Fe3O4/P （NaUA-St-BA） core-shell composite micro spheres were in situ prepared by soapless polymerization of styrene and butyl acrylate, with Fe3O4magnetic colloidal particles coated with NaUA. The results of IR and XRD analysis demonstrated that the desired polymer chains have been covalently bonded to the surface of Fe3O4 nano particles. The morphology analysis by TEM confirmed that the composite particles have the core-shell structure and a relatively uniform diameter of about 100nm. The magnetic properties of the obtained composite latex particles were measured by VSM and found that they exhibited super paramagnetic properties. Finally, the prepared magnetic composite particles latex is stable for several months.展开更多
To solve the problems of high Cr^(6+),Cr^(3+),SO_(4)^(2-)and H+concentrations,pollution and processing costs associated with agate dyeing industrial drainage,we prepared an immobilized gel mixture for the treatment of...To solve the problems of high Cr^(6+),Cr^(3+),SO_(4)^(2-)and H+concentrations,pollution and processing costs associated with agate dyeing industrial drainage,we prepared an immobilized gel mixture for the treatment of such drainage on the basis of microbial immobilization technology.The immobilized gel mixture was composed of sulfate-reducing bacteria(SRB),corn cob,and nano-Fe_(3)O_(4)(nFe_(3)O_(4)).We used a single-factor experiment to determine the optimal dose of each matrix component.We analyzed the mechanism underlying the treatment of agate dyeing wastewater with an immobilized gel mixture by X-ray diffraction and scanning electron microscopy detection.The results of the single-factor test showed that the best treatment was obtained under the following conditions for each matrix component:SRB mass percentage of 30%,nFe_(3)O_(4) dose of 3%,and corn cob mesh size of 100 and dose of 3%.On this basis,we conducted an L9(34)orthogonal experiment to determine the optimal proportion of each matrix component.The results showed that the best treatment was obtained when the gel mixture met the following conditions:SRB mass percentage of 40%,nFe_(3)O_(4) dose of 4%,and corn cob dose of 1%and mesh size of 100.Accordingly,the SO_(4)^(2-),Cr^(6+)and Cr^(3+)removal rates from the agate dyeing drainage were 70.54%,84.75%,and 73.80%,respectively;the total Fe and chemical oxygen demand releases were 1.086 mg·L^(-1)and 1104 mg·L^(-1),respectively;and the pH was 6.27.The gel mixture had the best treatment effect on agate dyeing wastewater under this composition ratio.展开更多
The strategic selection of appropriate preparation methods and binder strategies is crucial for enhancing the particle and combustion performance of pyrotechnic delay compositions(PDCs).This study,utilizing droplet mi...The strategic selection of appropriate preparation methods and binder strategies is crucial for enhancing the particle and combustion performance of pyrotechnic delay compositions(PDCs).This study,utilizing droplet microfluidics technology(DMT)and micron-scale raw materials,prepared spherical B/Pb_(3)O_(4) composite particles with varying concentrations of fluorine rubber(F_(2604)).The morphology,specific surface area,bulk density,flowability,friction sensitivity,thermal decomposition,and combustion performance of these microspheres were characterized.The results indicate that as the binder content increases,the particle size of the microspheres first decreases and then increases,the specific surface area decreases,and the bulk density increases,correlating with tighter binding of the reactant powders by the binder.Furthermore,tighter powder-to-powder binding results in a progressive decrease in the thermal decomposition peak temperature of the samples(from 404.2℃ to 346.4℃).Additionally,increased binder content reduces the friction sensitivity and combustion rate of the samples,which is attributed to the energy absorption properties of the binder.Compared to the control group,the microsphere samples exhibit significantly enhanced bulk density,flowability,friction safety,and combustion delay precision,potentially improving the reliability of PDCs in ignition sequences.展开更多
NH_(3)is an essential feedstock for fertilizer synthesis.Industry-scale NH_(3)synthesis mostly relies on the Haber-Bosch method,however,which suffers from massive CO_(2) emission and high energy consumption.Electrocat...NH_(3)is an essential feedstock for fertilizer synthesis.Industry-scale NH_(3)synthesis mostly relies on the Haber-Bosch method,however,which suffers from massive CO_(2) emission and high energy consumption.Electrocatalytic NO_(3)-reduction is an attractive substitute to the Haber-Bosch method for synthesizing NH_(3)under mild conditions.As this reaction will produce a variety of products,it highly desires efficient and selective electrocatalyst for NH_(3)generation.Here,we report in situ grown Fe_(3)O_(4)particle on stainless steel(Fe_(3)O_(4)/SS)as a high-efficiency electrocatalyst for NO_(3)^(-)reduction to NH_(3).In 0.1 M NaOH with 0.1 M NaNO_(3),such Fe_(3)O_(4)/SS reaches a remarkable Faradaic efficiency of 91.5%and a high NH_(3)yield of 10,145μg·h^(-1)·cm^(-2)at-0.5 V vs.reversible hydrogen electrode(RHE).Furthermore,it owns robust structural and electrochemical stability.This work provides useful guidelines to expand the scope of metallic oxide electrocatalysts for NH_(3)synthesis.The catalytic mechanism is uncovered and discussed further by theoretical calculations.展开更多
To facilitate the recovery of Pb/SiO_(2) catalyst,magnetic Pb/Fe_(3)O_(4)/SiO_(2) samples were prepared separately by emulsification,sol-gel and incipient impregnation methods.The catalyst samples were characterized b...To facilitate the recovery of Pb/SiO_(2) catalyst,magnetic Pb/Fe_(3)O_(4)/SiO_(2) samples were prepared separately by emulsification,sol-gel and incipient impregnation methods.The catalyst samples were characterized by means of X-ray diffraction and N_(2) adsorption-desorption,and their catalytic activity was investigated in the reaction for synthesizing propylene carbonate from urea and 1,2-propylene glycol.When the gelatin was applied in the preparation of Fe_(3)O_(4) at 60℃ and the pH value was controlled at 4 in the preparation of Fe_(3)O_(4)/SiO_(2),the Pb/Fe_(3)O_(4)/SiO_(2) sample shows good catalytic activity and magnetism.Under the reaction conditions of a reaction temperature of 180℃,reaction time of 2h,catalyst percentage of 1.7 wt-% and a molar ratio of urea to PG of 1∶4,the yield of propylene carbonate attained was 87.7%.展开更多
基金supported by the China National Funds for Distinguished Young Scientists (51925104)the National Natural Science Foundation of China (NSFC) (51871162 and 52173251)+1 种基金NSFC-Guangdong Province Joint Program (U21A2084)the Central Guidance on Local Science and Technology Development Fund of Hebei Province (226Z1303G).
文摘Infections with multidrug-resistant(MDR)Gram-negative bacteria,such as MDR Escherichia coli(E.coli),remain a challenge due to the lack of safe antibiotics and high fatality rates under anti-infection therapies.This work presents a form of biomimetic intelligent catalysis inspired by the selective biocatalytic property of macrophages(MΦs),consisting of an intelligent controlling center(a living MΦ)and a Fenton reaction catalyst(Fe_(3)O_(4)@poly(lactic-co-glycolic acid)(PLGA)nanoparticles)for killing MDR E.coli without harming normal cells.The MΦ-Fe_(3)O_(4)@PLGA particles(i.e.,the intelligent catalysis particles)exhibit selective biocatalysis activity toward MDR E.coli by producing H_(2)O_(2) and lipid droplets(LDs).This process activates the lipid metabolism and glycan biosynthesis and metabolism pathways based on the result of RNA sequencing data analysis.The H_(2)O_(2) further reacts with Fe_(3)O_(4)@PLGA to form highly toxic hydroxyl radicals(·OH),while the LDs contain antimicrobial peptides and can target MDR E.coli.The highly toxicOH and antimicrobial peptides are shown to combat with MDR E.coli,such that the antibacterial efficiency of the MΦ-Fe_(3)O_(4)@PLGA particles against MDR E.coli is 99.29%±0.31%in vitro.More importantly,after several passages,the intelligent catalysis function of the MΦ-Fe_(3)O_(4)@PLGA particles is well maintained.Hence,the concept of biomimetic intelligent catalysts displays potential for treating diseases other than infections.
基金Project 59573011 was supported by National Natural Science Foundation of China
文摘Fe_3O_4/Polystyrene(PSt) magnetic particles with core/shell structure have been prepared in thepresence of Fe_3O_4 magnetic fluid in ethanol/water medium by dispersion polymeriation of styrene. A Fe_3O_4particle formation mechanism was proposed. According to this mechanism, the size of particle nuclei isdetermined by the extent of aggregation of Fe_3O_4 /oligomer. Magnetic particles with diameter ranging from 5to 200 μm were prepared under different reaction conditions. Some polymerization parameters such as theconcentration of monomer, stabilizer, initiator, and ethanol which affect particle size and size distribution arediscussed and their effect on particle formation are explained by the proposed mechanism.
文摘Fe3O4/P （NaUA-St-BA） core-shell composite micro spheres were in situ prepared by soapless polymerization of styrene and butyl acrylate, with Fe3O4magnetic colloidal particles coated with NaUA. The results of IR and XRD analysis demonstrated that the desired polymer chains have been covalently bonded to the surface of Fe3O4 nano particles. The morphology analysis by TEM confirmed that the composite particles have the core-shell structure and a relatively uniform diameter of about 100nm. The magnetic properties of the obtained composite latex particles were measured by VSM and found that they exhibited super paramagnetic properties. Finally, the prepared magnetic composite particles latex is stable for several months.
基金funded by the National Natural Science Foundation of China(41672247,41102157,51304114)Liaoning Provincial Natural Science Foundation of China(2015020619)+1 种基金and Liaoning Provincial Department of Education(LJYL031,LJ2017FAL016)the project was supported by the discipline innovation team of Liaoning Technical University(LNTU20TD-21).
文摘To solve the problems of high Cr^(6+),Cr^(3+),SO_(4)^(2-)and H+concentrations,pollution and processing costs associated with agate dyeing industrial drainage,we prepared an immobilized gel mixture for the treatment of such drainage on the basis of microbial immobilization technology.The immobilized gel mixture was composed of sulfate-reducing bacteria(SRB),corn cob,and nano-Fe_(3)O_(4)(nFe_(3)O_(4)).We used a single-factor experiment to determine the optimal dose of each matrix component.We analyzed the mechanism underlying the treatment of agate dyeing wastewater with an immobilized gel mixture by X-ray diffraction and scanning electron microscopy detection.The results of the single-factor test showed that the best treatment was obtained under the following conditions for each matrix component:SRB mass percentage of 30%,nFe_(3)O_(4) dose of 3%,and corn cob mesh size of 100 and dose of 3%.On this basis,we conducted an L9(34)orthogonal experiment to determine the optimal proportion of each matrix component.The results showed that the best treatment was obtained when the gel mixture met the following conditions:SRB mass percentage of 40%,nFe_(3)O_(4) dose of 4%,and corn cob dose of 1%and mesh size of 100.Accordingly,the SO_(4)^(2-),Cr^(6+)and Cr^(3+)removal rates from the agate dyeing drainage were 70.54%,84.75%,and 73.80%,respectively;the total Fe and chemical oxygen demand releases were 1.086 mg·L^(-1)and 1104 mg·L^(-1),respectively;and the pH was 6.27.The gel mixture had the best treatment effect on agate dyeing wastewater under this composition ratio.
基金supported by National Natural Science Foundation of China(grant No.22005275).
文摘The strategic selection of appropriate preparation methods and binder strategies is crucial for enhancing the particle and combustion performance of pyrotechnic delay compositions(PDCs).This study,utilizing droplet microfluidics technology(DMT)and micron-scale raw materials,prepared spherical B/Pb_(3)O_(4) composite particles with varying concentrations of fluorine rubber(F_(2604)).The morphology,specific surface area,bulk density,flowability,friction sensitivity,thermal decomposition,and combustion performance of these microspheres were characterized.The results indicate that as the binder content increases,the particle size of the microspheres first decreases and then increases,the specific surface area decreases,and the bulk density increases,correlating with tighter binding of the reactant powders by the binder.Furthermore,tighter powder-to-powder binding results in a progressive decrease in the thermal decomposition peak temperature of the samples(from 404.2℃ to 346.4℃).Additionally,increased binder content reduces the friction sensitivity and combustion rate of the samples,which is attributed to the energy absorption properties of the binder.Compared to the control group,the microsphere samples exhibit significantly enhanced bulk density,flowability,friction safety,and combustion delay precision,potentially improving the reliability of PDCs in ignition sequences.
基金This work was supported by the National Natural Science Foundation of China(No.22072015).
文摘NH_(3)is an essential feedstock for fertilizer synthesis.Industry-scale NH_(3)synthesis mostly relies on the Haber-Bosch method,however,which suffers from massive CO_(2) emission and high energy consumption.Electrocatalytic NO_(3)-reduction is an attractive substitute to the Haber-Bosch method for synthesizing NH_(3)under mild conditions.As this reaction will produce a variety of products,it highly desires efficient and selective electrocatalyst for NH_(3)generation.Here,we report in situ grown Fe_(3)O_(4)particle on stainless steel(Fe_(3)O_(4)/SS)as a high-efficiency electrocatalyst for NO_(3)^(-)reduction to NH_(3).In 0.1 M NaOH with 0.1 M NaNO_(3),such Fe_(3)O_(4)/SS reaches a remarkable Faradaic efficiency of 91.5%and a high NH_(3)yield of 10,145μg·h^(-1)·cm^(-2)at-0.5 V vs.reversible hydrogen electrode(RHE).Furthermore,it owns robust structural and electrochemical stability.This work provides useful guidelines to expand the scope of metallic oxide electrocatalysts for NH_(3)synthesis.The catalytic mechanism is uncovered and discussed further by theoretical calculations.
基金This work has been supported by the National Natural Science Foundation of China(Grant No.20576025)the Hebei Provincial Fund for Natural Science(B2007000010).
文摘To facilitate the recovery of Pb/SiO_(2) catalyst,magnetic Pb/Fe_(3)O_(4)/SiO_(2) samples were prepared separately by emulsification,sol-gel and incipient impregnation methods.The catalyst samples were characterized by means of X-ray diffraction and N_(2) adsorption-desorption,and their catalytic activity was investigated in the reaction for synthesizing propylene carbonate from urea and 1,2-propylene glycol.When the gelatin was applied in the preparation of Fe_(3)O_(4) at 60℃ and the pH value was controlled at 4 in the preparation of Fe_(3)O_(4)/SiO_(2),the Pb/Fe_(3)O_(4)/SiO_(2) sample shows good catalytic activity and magnetism.Under the reaction conditions of a reaction temperature of 180℃,reaction time of 2h,catalyst percentage of 1.7 wt-% and a molar ratio of urea to PG of 1∶4,the yield of propylene carbonate attained was 87.7%.
