Increasing attention has been paid to radioactive wastewater to direct discharge in Japan or accidental leaks.Strontium-90(90Sr)and Cobalt-60(^(60)Co)are the most hazardous nuclides in waste discharged form nuclear re...Increasing attention has been paid to radioactive wastewater to direct discharge in Japan or accidental leaks.Strontium-90(90Sr)and Cobalt-60(^(60)Co)are the most hazardous nuclides in waste discharged form nuclear reactors.Because of their high solubility and long half-lives,these radioisotopes can persist for hundreds of years before decaying to negligible levels.Herein,a green and biodegradable material nanoscale zero-valent iron(nZVI)supported by bacterial cellulose particles(BCP-nZVI)is constructed for the first time to adsorb Co^(2+)and Sr^(2+)in single and binary systems.BCP-nZVI shows superior adsorption capacities of Co^(2+)and Sr^(2+)in a single system within a wide range of pH values from 5 to 7,while the coexistence of Co^(2+)adsorption inhibits the Sr^(2+)in binary system.Pseudo-second-order dynamics model and Langmuir isothermal model can be indicated the BCP-nZVI adsorption progress with 107.10 mg/g(Co^(2+))and 64.96 mg/g(Sr^(2+))maximum adsorption capacity.BCP-nZVI has outstanding stability,allowing it to be stored for more than one month with compromising its performance.More importantly,BCP-nZVI exhibits exceptional removal efficiency of Co^(2+)(92.53%)and Sr^(2+)(58.62%)removal in natural seawater systems.The mechanism investigation illustrates the high adsorption capacity of BCP-nZVI for Co^(2+)is controlled by redox and hydroxyl complexation.While Sr^(2+)is controlled by hydroxyl complexed adsorption,thus it has weak against interference by cations like Na^(+),Ca^(2+),etc.BCP-nZVI exhibits the advantages of high adsorption capacity,wide pH range,strong stability,and good applicability in natural seawater,which has excellent potential for application in radioactive ions removal.展开更多
SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant dispari...SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.展开更多
Although sonodynamic therapy(SDT)is a promising cancer treatment that induces DNA and macromolecular damage through the generation of reactive oxygen species(ROS),its therapeutic efficacy is limited by local hypoxia a...Although sonodynamic therapy(SDT)is a promising cancer treatment that induces DNA and macromolecular damage through the generation of reactive oxygen species(ROS),its therapeutic efficacy is limited by local hypoxia and ROS defense mechanisms in tumors.This study propose d a novel tumor treatment approach,focusing on ROS-mediated therapy by targ eting the nucleus and depleting glutathione(GSH)levels,which was achieved through a nanoplatform(Pt^(2+)-CDs@PpIX)with integrated functions including GSH detection and depletion,pH-responsive drug release,and nuclear targeting.The Pt^(2+)-CDs@PpIX nanoplatform effectively differentiated normal and cancer cells and also exhibited excellent biocompatibility.Depletion of GSH levels and increased ROS sensitivity of cells significantly improved the effectiveness of SDT,as demonstrated in vitro using Pt^(2+)-CDs@PpIX,which also exhibited significant cellular uptake.Pt^(2+)-CDs@PpIX exerted potent antitumor effects in both two-dimensional and three-dimensional tum or microenvironment models(3 DM-7721).Moreover,in 3 DM-7721 models,hepatoma cells(SMMC-7721)demonstrated significant inhibition of motility,invasion,and colony formation after exposure to Pt^(2+)-CDs@PpIX.Furthermore,intravenous administration of the Pt^(2+)-CDs@PpIX nanoplatform enabled precise and rapid tumor-targeting,followed by ultrasound-triggered therapy,without adverse effects in nude mice.Hence,this nanoplatform provides a promising strategy for designing cancer therapies and delivering nuclear-targeted drugs.展开更多
As an important means to solve water shortage,reclaimed water has been widely used for landscape water supply.However,with the emergence of large-scale epidemic diseases such as SARS,avian influenza and COVID-19 in re...As an important means to solve water shortage,reclaimed water has been widely used for landscape water supply.However,with the emergence of large-scale epidemic diseases such as SARS,avian influenza and COVID-19 in recent years,people are increasingly concerned about the public health safety of reclaimed water discharged into landscape water,especially the pathogenic microorganisms in it.In this study,the water quality and microorganisms of the Old Summer Palace,a landscape water body with reclaimed water as the only replenishment water source,were tracked through long-term dynamic monitoring.And the health risks of indicator microorganisms were analyzed using Quantitative Microbial Risk Assessment(QMRA).It was found that the concentration of indicator microorganisms Enterococcus(ENT),Escherichia coli(EC)and Fecal coliform(FC)generally showed an upward trend along the direction of water flow and increased by more than 0.6 log at the end of the flow.The concentrations of indicator microorganisms were higher in summer and autumn than those in spring.And there was a positive correlation between the concentration of indicator microorganisms and COD.Further research suggested that increased concentration of indicator microorganisms also led to increased health risks,which were more than 30%higher in other areas of the park than the water inlet area and required special attention.In addition,(water)surface operation exposure pathway had much higher health risks than other pathways and people in related occupations were advised to take precautions to reduce the risks.展开更多
There are many DOA estimation methods based on different signal features, and these methods are often evaluated by experimental results, but lack the necessary theoretical basis. Therefore, a direction of arrival (DOA...There are many DOA estimation methods based on different signal features, and these methods are often evaluated by experimental results, but lack the necessary theoretical basis. Therefore, a direction of arrival (DOA) estimation system based on self-organizing map (SOM) and designed for arbitrarily distributed sensor array is proposed. The essential principle of this method is that the map from distance difference of arrival (DDOA) to DOA is Lipschitz continuity, it indicates the similar topology between them, and thus Kohonen SOM is a suitable network to classify DOA through DDOA. The simulation results show that the DOA estimation errors are less than 1° for most signals between 0° to 180°. Compared to MUSIC, Root-MUSIC, ESPRIT, and RBF, the errors of signals under signal-to-noise ratios (SNR) declines from 20 dB to 2 dB are robust, SOM is better than RBF and almost close to MUSIC. Further, the network can be trained in advance, which makes it possible to be implemented in real-time.展开更多
Carbon nanotube(CNT)composite materials are very attractive for use in neural tissue engineering and biosensor coatings.CNT scaffolds are excellent mimics of extracellular matrix due to their hydrophilicity,viscosity,...Carbon nanotube(CNT)composite materials are very attractive for use in neural tissue engineering and biosensor coatings.CNT scaffolds are excellent mimics of extracellular matrix due to their hydrophilicity,viscosity,and biocompatibility.CNTs can also impart conductivity to other insulating materials improve mechanical stability guide neuronal cell behavior and trigger axon regeneration.The performance of chitosan(CS)/polyethylene glycol(PEG)composite scaffolds could be optimized by introducing multi-walled CNTs(MWCNTs).CS/PEG/CNT composite scaffolds with CNT content of 1%,3%,and 5%(1%=0.01 g/mL)were prepared by freeze-drying.Their physical and chemical properties and biocompatibility were evaluated.Scanning electron microscopy(SEM)showed that the composite scaffolds had a highly connected porous structure.Transmission electron microscope(TEM)and Raman spectroscopy proved that the CNTs were well dispersed in the CS/PEG matrix and combined with the CS/PEG nanofiber bundles.MWCNTs enhanced the elastic modulus of the scaffold.The porosity of the scaffolds ranged from 83%to 96%.They reached a stable water swelling state within 24 h,and swelling decreased with increasing MWCNT concentration.The electrical conductivity and cell adhesion rate of the scaffolds increased with increasing MWCNT content.Immunofluorescence showed that rat pheochromocytoma(PC12)cells grown in the scaffolds had characteristics similar to nerve cells.We measured changes in the expression of nerve cell markers by quantitative real-time polymerase chain reaction(qRT-PCR),and found that PC12 cells cultured in the scaffolds expressed growth-associated protein 43(GAP43),nerve growth factor receptor(NGFR),and class IIIβ-tubulin(TUBB3)proteins.Preliminary research showed that the prepared CS/PEG/CNT scaffold has good biocompatibility and can be further applied to neural tissue engineering research.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51778618 and 52070192)the State Key Laboratory of Materials-Oriented Chemical Engineering(No.SKL-MCE-23B09)the open fund of Information Materials and Intelligent Sensing Laboratory of Anhui Province(No.IMIS202213).
文摘Increasing attention has been paid to radioactive wastewater to direct discharge in Japan or accidental leaks.Strontium-90(90Sr)and Cobalt-60(^(60)Co)are the most hazardous nuclides in waste discharged form nuclear reactors.Because of their high solubility and long half-lives,these radioisotopes can persist for hundreds of years before decaying to negligible levels.Herein,a green and biodegradable material nanoscale zero-valent iron(nZVI)supported by bacterial cellulose particles(BCP-nZVI)is constructed for the first time to adsorb Co^(2+)and Sr^(2+)in single and binary systems.BCP-nZVI shows superior adsorption capacities of Co^(2+)and Sr^(2+)in a single system within a wide range of pH values from 5 to 7,while the coexistence of Co^(2+)adsorption inhibits the Sr^(2+)in binary system.Pseudo-second-order dynamics model and Langmuir isothermal model can be indicated the BCP-nZVI adsorption progress with 107.10 mg/g(Co^(2+))and 64.96 mg/g(Sr^(2+))maximum adsorption capacity.BCP-nZVI has outstanding stability,allowing it to be stored for more than one month with compromising its performance.More importantly,BCP-nZVI exhibits exceptional removal efficiency of Co^(2+)(92.53%)and Sr^(2+)(58.62%)removal in natural seawater systems.The mechanism investigation illustrates the high adsorption capacity of BCP-nZVI for Co^(2+)is controlled by redox and hydroxyl complexation.While Sr^(2+)is controlled by hydroxyl complexed adsorption,thus it has weak against interference by cations like Na^(+),Ca^(2+),etc.BCP-nZVI exhibits the advantages of high adsorption capacity,wide pH range,strong stability,and good applicability in natural seawater,which has excellent potential for application in radioactive ions removal.
基金Supported by National Natural Science Foundation of China(Grant Nos.52475480,51805334)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515030249,2023A1515110059)Shenzhen Science and Technology Program(Grant No.GJHZ20220913144212023).
文摘SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.
基金supported by the National Natural Science Foundation of China(No.62031022)the Sha nxi Provincial Basic Research Project(Nos.202103021221006 and 20210302123040)+2 种基金the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2021L044)the Key R&D Program of Shanxi Province(No.202302130501006)the Shanxi‒Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SX-TD026).
文摘Although sonodynamic therapy(SDT)is a promising cancer treatment that induces DNA and macromolecular damage through the generation of reactive oxygen species(ROS),its therapeutic efficacy is limited by local hypoxia and ROS defense mechanisms in tumors.This study propose d a novel tumor treatment approach,focusing on ROS-mediated therapy by targ eting the nucleus and depleting glutathione(GSH)levels,which was achieved through a nanoplatform(Pt^(2+)-CDs@PpIX)with integrated functions including GSH detection and depletion,pH-responsive drug release,and nuclear targeting.The Pt^(2+)-CDs@PpIX nanoplatform effectively differentiated normal and cancer cells and also exhibited excellent biocompatibility.Depletion of GSH levels and increased ROS sensitivity of cells significantly improved the effectiveness of SDT,as demonstrated in vitro using Pt^(2+)-CDs@PpIX,which also exhibited significant cellular uptake.Pt^(2+)-CDs@PpIX exerted potent antitumor effects in both two-dimensional and three-dimensional tum or microenvironment models(3 DM-7721).Moreover,in 3 DM-7721 models,hepatoma cells(SMMC-7721)demonstrated significant inhibition of motility,invasion,and colony formation after exposure to Pt^(2+)-CDs@PpIX.Furthermore,intravenous administration of the Pt^(2+)-CDs@PpIX nanoplatform enabled precise and rapid tumor-targeting,followed by ultrasound-triggered therapy,without adverse effects in nude mice.Hence,this nanoplatform provides a promising strategy for designing cancer therapies and delivering nuclear-targeted drugs.
基金supported by the National Natural Science Foundation of China(Nos.52070192 and 51778618).
文摘As an important means to solve water shortage,reclaimed water has been widely used for landscape water supply.However,with the emergence of large-scale epidemic diseases such as SARS,avian influenza and COVID-19 in recent years,people are increasingly concerned about the public health safety of reclaimed water discharged into landscape water,especially the pathogenic microorganisms in it.In this study,the water quality and microorganisms of the Old Summer Palace,a landscape water body with reclaimed water as the only replenishment water source,were tracked through long-term dynamic monitoring.And the health risks of indicator microorganisms were analyzed using Quantitative Microbial Risk Assessment(QMRA).It was found that the concentration of indicator microorganisms Enterococcus(ENT),Escherichia coli(EC)and Fecal coliform(FC)generally showed an upward trend along the direction of water flow and increased by more than 0.6 log at the end of the flow.The concentrations of indicator microorganisms were higher in summer and autumn than those in spring.And there was a positive correlation between the concentration of indicator microorganisms and COD.Further research suggested that increased concentration of indicator microorganisms also led to increased health risks,which were more than 30%higher in other areas of the park than the water inlet area and required special attention.In addition,(water)surface operation exposure pathway had much higher health risks than other pathways and people in related occupations were advised to take precautions to reduce the risks.
文摘There are many DOA estimation methods based on different signal features, and these methods are often evaluated by experimental results, but lack the necessary theoretical basis. Therefore, a direction of arrival (DOA) estimation system based on self-organizing map (SOM) and designed for arbitrarily distributed sensor array is proposed. The essential principle of this method is that the map from distance difference of arrival (DDOA) to DOA is Lipschitz continuity, it indicates the similar topology between them, and thus Kohonen SOM is a suitable network to classify DOA through DDOA. The simulation results show that the DOA estimation errors are less than 1° for most signals between 0° to 180°. Compared to MUSIC, Root-MUSIC, ESPRIT, and RBF, the errors of signals under signal-to-noise ratios (SNR) declines from 20 dB to 2 dB are robust, SOM is better than RBF and almost close to MUSIC. Further, the network can be trained in advance, which makes it possible to be implemented in real-time.
基金This study was supported by the National Natural Science Foundation of China(Nos.51975400 and 62031022)the Shanxi Provincial Key Medical Scientific Research Project(No.2020XM06),China.
文摘Carbon nanotube(CNT)composite materials are very attractive for use in neural tissue engineering and biosensor coatings.CNT scaffolds are excellent mimics of extracellular matrix due to their hydrophilicity,viscosity,and biocompatibility.CNTs can also impart conductivity to other insulating materials improve mechanical stability guide neuronal cell behavior and trigger axon regeneration.The performance of chitosan(CS)/polyethylene glycol(PEG)composite scaffolds could be optimized by introducing multi-walled CNTs(MWCNTs).CS/PEG/CNT composite scaffolds with CNT content of 1%,3%,and 5%(1%=0.01 g/mL)were prepared by freeze-drying.Their physical and chemical properties and biocompatibility were evaluated.Scanning electron microscopy(SEM)showed that the composite scaffolds had a highly connected porous structure.Transmission electron microscope(TEM)and Raman spectroscopy proved that the CNTs were well dispersed in the CS/PEG matrix and combined with the CS/PEG nanofiber bundles.MWCNTs enhanced the elastic modulus of the scaffold.The porosity of the scaffolds ranged from 83%to 96%.They reached a stable water swelling state within 24 h,and swelling decreased with increasing MWCNT concentration.The electrical conductivity and cell adhesion rate of the scaffolds increased with increasing MWCNT content.Immunofluorescence showed that rat pheochromocytoma(PC12)cells grown in the scaffolds had characteristics similar to nerve cells.We measured changes in the expression of nerve cell markers by quantitative real-time polymerase chain reaction(qRT-PCR),and found that PC12 cells cultured in the scaffolds expressed growth-associated protein 43(GAP43),nerve growth factor receptor(NGFR),and class IIIβ-tubulin(TUBB3)proteins.Preliminary research showed that the prepared CS/PEG/CNT scaffold has good biocompatibility and can be further applied to neural tissue engineering research.
