Waterborne ultrafine particles of epoxy resin were prepared by phase inversion technique. The results of SEM revealed that the particles diameter was in the range of 50 to 100 nm and the effects on amount of water req...Waterborne ultrafine particles of epoxy resin were prepared by phase inversion technique. The results of SEM revealed that the particles diameter was in the range of 50 to 100 nm and the effects on amount of water required at phase inversion point were also discussed.展开更多
Air pollution by particulate matter(PM)is one of the main threats to human health,particularly in large cities where pollution levels are continually exceeded.According to their source of emission,geography,and local ...Air pollution by particulate matter(PM)is one of the main threats to human health,particularly in large cities where pollution levels are continually exceeded.According to their source of emission,geography,and local meteorology,the pollutant particles vary in size and composition.These particles are conditioned to the aerodynamic diameter and thus classified as coarse(2.5–10μm),fine(0.1–2.5μm),and ultrafine(<0.1μm),where the degree of toxicity becomes greater for smaller particles.These particles can get into the lungs and translocate into vital organs due to their size,causing significant human health consequences.Besides,PM pollutants have been linked to respiratory conditions,genotoxic,mutagenic,and carcinogenic activity in human beings.This paper presents an overview of emission sources,physicochemical characteristics,collection and measurement methodologies,toxicity,and existing control mechanisms for ultrafine particles(UFPs)in the last fifteen years.展开更多
Fluidized chemical vapor deposition (FCVD) technology was developed for coating SnO 2 thin film on ultrafine Al 2O 3 particles.Transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) ...Fluidized chemical vapor deposition (FCVD) technology was developed for coating SnO 2 thin film on ultrafine Al 2O 3 particles.Transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) analyses demonstrated that SnO 2 films with different structures were deposited through controlling the coating temperature, reactant concentration, etc .. Nanocrystalline SnO 2 film was formed at 572.15K by gas phase reaction of SnCl 4 and H 2O.Electron probe microanalyser (EPMA) and energy dispersive spectrometer (EDS) analyses indicated that the distribution of nanocrystalline SnO 2 over inner and outer part of the Al 2O 3 agglomerates was homogeneous.展开更多
Ultrafine particles prepared by evaporating pure Fe in CH4 atmosphere using arc-dischargeheating method, were found to consist of Fe-C solid solution, γ-Fe and Fe3C phases. EfFect of annealing temperature on phase tr...Ultrafine particles prepared by evaporating pure Fe in CH4 atmosphere using arc-dischargeheating method, were found to consist of Fe-C solid solution, γ-Fe and Fe3C phases. EfFect of annealing temperature on phase transformation and hyperfine interactions has been investigated by Mossbauer spectroscopy, X-ray diffraction (XRD), differential thermal analysis and thermogravimetry (DTA-TG), transmission electron microscopy (TEM), oxygen determination and vibrating sample magnetometer (VSM) measurements. It was observed that phase transformation of γ-Fe to α-Fe occurs during annealing in vacuum. The mechanism causing the change of hyperfine interactions with annealing temperature differs for Fe-C solution and interstitial compounds. DifFerence of hyperfine interactions of Fe-C solid solution in the starting sample and its annealed samples is ascribed to the improvement of activation of interstitial carbon atoms. Stress-relieving in structure of annealed Fe3C particle can result in a weak influence on hyperfine interactions. Parameters fitted to the Mossbauer spectra show the existence of superparamagnetism in all the samples. Absorbed and combined oxygen on particle surface of the starting sample were determined.展开更多
The composition distribution in Fe50Pd50 alloy ultrafine particles prepared by inert gas condensation method was investigated in details by means of X-ray diffraction technique through deconvolution of the X-ray diffr...The composition distribution in Fe50Pd50 alloy ultrafine particles prepared by inert gas condensation method was investigated in details by means of X-ray diffraction technique through deconvolution of the X-ray diffraction data. The microscopic composition distribution in the alloy UFP was identified, which is caused by nonuniformity of the melt, fractional distillation during the evaporation process and statistical fluctuation during nucleation and coalescence of the alloy particles. The composition distribution affects the properties of the alloy UFP展开更多
A model for the size-dependent initial sintering temperature of ultrafine particles was established. The theoretical predictions for the size-dependent sintering temperatures of W, Ni and Ag ultrafine particles are co...A model for the size-dependent initial sintering temperature of ultrafine particles was established. The theoretical predictions for the size-dependent sintering temperatures of W, Ni and Ag ultrafine particles are consistent with available experimental展开更多
The deposition of ultrafine particles, in the human respiratory tract, from four highly impacted megacities across the globe, was evaluated by using a pulmonary deposition model. It was found that, for the locations s...The deposition of ultrafine particles, in the human respiratory tract, from four highly impacted megacities across the globe, was evaluated by using a pulmonary deposition model. It was found that, for the locations studied, an average of 62% of atmospheric particles was retained in the respiratory system. As expected, the model shows that smaller particles penetrate deeper in the airways. In addition, it’s shown that children are more susceptible than adults, retaining 8% more ultrafine particles.展开更多
Ce0.6Zr0.4O2 solid solution ultrafine particle was prepared in the cyclohexane/water/OP-10/n-hexanol reversed microemulsion. The quasi-ternary phase diagram investigations showed that the system has narrow W/O type mi...Ce0.6Zr0.4O2 solid solution ultrafine particle was prepared in the cyclohexane/water/OP-10/n-hexanol reversed microemulsion. The quasi-ternary phase diagram investigations showed that the system has narrow W/O type microemulison region, so it is the proper system to prepare Ce0.6Zr0.4O2 solid solution ultrafine particle. Some physical-chemical techniques such as TG/DTA, XRD, BET, and HRTEM are used to characterize the resultant powders. The results show that the fluorite cubic Ce0.6Zr0.4O2 solid solution is obtained at 400 ℃. The surface area is (146.7 m^2·g^-1), which is higher than the surface area for sol-gel prepared sample (59.5m^2·g^-1). HRTEM images indicated that the Ce0.6Zr0.4O2 solid solution ultrafine particle is well-crystallized, narrow size distribution, less agglomeration, within mean size of 5 -7 nm.展开更多
Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measure...Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measurements of the saturation magnetization and coercivity force. Both b.c.c and f.c.c phase exist within a wide range for Fe 100- x Ni x , while x ≤45. The effective magnetic anisotropy K e was measured by applying the law of approach to saturation. The value of K e decreases with an increase of Ni content. It is noticed that the strain anisotropy makes a large contribution to the magnetic anisotropy. The estimation of grain size leads to the determination of the single domain critical size and domain wall energy. The exchange stiffness and exchange integral deduced from the relationship between the effective magnetic anisotropy and domain wall energy are in agreement with that calculated by other methods.展开更多
Particulate pollution is a global risk factor that seriously threatens human health.Fine particles(FPs)and ultrafine particles(UFPs)have small particle diameters and large specific surface areas,which can easily adsor...Particulate pollution is a global risk factor that seriously threatens human health.Fine particles(FPs)and ultrafine particles(UFPs)have small particle diameters and large specific surface areas,which can easily adsorb metals,microorganisms and other pollutants.FPs and UFPs can enter the human body in multiple ways and can be easily and quickly absorbed by the cells,tissues and organs.In the body,the particles can induce oxidative stress,inflammatory response and apoptosis,furthermore causing great adverse effects.Epidemiological studies mainly take the population as the research object to study the distribution of diseases and health conditions in a specific population and to focus on the identification of influencing factors.However,the mechanism by which a substance harms the health of organisms is mainly demonstrated through toxicological studies.Combining epidemiological studies with toxicological studies will provide a more systematic and comprehensive understanding of the impact of PM on the health of organisms.In this review,the sources,compositions,and morphologies of FPs and UFPs are briefly introduced in the first part.The effects and action mechanisms of exposure to FPs and UFPs on the heart,lungs,brain,liver,spleen,kidneys,pancreas,gastrointestinal tract,joints and reproductive system are systematically summarized.In addition,challenges are further pointed out at the end of the paper.This work provides useful theoretical guidance and a strong experimental foundation for investigating and preventing the adverse effects of FPs and UFPs on human health.展开更多
The development of ultrafine particles provided a new way to solve problems in the fields of energy,environment,and medicine,and had become one of the most promising technologies.Therefore,the application of ultrafine...The development of ultrafine particles provided a new way to solve problems in the fields of energy,environment,and medicine,and had become one of the most promising technologies.Therefore,the application of ultrafine particles required the development of cleaner,greener,and more efficient preparation methods.The new freeze-dissolving technology has been applied in manufacturing of KHCO_(3)ultrafine particles,with an aqueous solution of 0.02-0.1 g KHCO_(3)/g water.Frozen ice particles were formed after dripping the solution into liquid nitrogen.The antisolvent ethanol was used to dissolve the ice spherical template at a temperature below 273.15 K,and the pre-formed KHCO_(3)ultrafine particles inside the ice template remained in the ethanol aqueous solution.The ice particles were put into the freeze dryer to isolate the ultrafine KHCO_(3)particles.Compared with the particles produced with traditional freeze-drying technology,the ultrafine powder/particles produced by the freeze-dissolving technology were smaller with narrower size distribution.The freeze-dissolving technology has demonstrated a much more sustainable and efficient manufacturing process than the traditional freeze-drying process.In addition,the influence of the concentrations of KHCO_(3)and the sizes of ice particles were investigated with the discussions of mechanisms.展开更多
Ambient particles severely threaten human health worldwide.Compared to larger particles,ultrafine particles(UFPs)are highly concentrated in ambient environments,have a larger specific surface area,and are retained for...Ambient particles severely threaten human health worldwide.Compared to larger particles,ultrafine particles(UFPs)are highly concentrated in ambient environments,have a larger specific surface area,and are retained for a longer time in the lung.Recent studies have found that they can be transported into various extra-pulmonary organs by crossing the air-blood barrier(ABB).Therefore,to understand the adverse effects of UFPs,it is crucial to thoroughly investigate their bio-distribution and clearance pathways in vivo after inhalation,as well as their toxicological mechanisms.This review highlights emerging evidence on the bio-distribution of UFPs in pulmonary and extra-pulmonary organs.It explores how UFPs penetrate the ABB,the blood-brain barrier(BBB),and the placental barrier(PB)and subsequently undergo clearance by the liver,kidney,or intestine.In addition,the potential underlying toxicological mechanisms of UFPs are summarized,providing fundamental insights into how UFPs induce adverse health effects.展开更多
Fine and ultrafine particles possess great potential for industrial applications ascribed from their huge specific surface area and ability to provide good gas–solid contact.However,these powders are inherently cohes...Fine and ultrafine particles possess great potential for industrial applications ascribed from their huge specific surface area and ability to provide good gas–solid contact.However,these powders are inherently cohesive,making it challenging to achieve smooth flow and fluidization.This challenge can be well-resolved by nanoparticle modulation(nano-modulation),where a small amount of nanoparticles is uniformly mixed with the cohesive fine/ultrafine powders.Through nano-modulation,the fluidization system of cohesive powders exhibits distinguishable minimum fluidization velocity,enlarged bed expansion ratio(particularly the dense phase expansion),and scarcer,smaller,and slower moving bubbles,indicating improved flow and fluidization quality.The purpose of the current work is to systematically summarize the state-of-the-art progress in the fluidization and utilization of fine and ultrafine particles via the nanoparticle modulation method.Accordingly,a broader audience can be enlightened regarding this promising fine/ultrafine particle fluidization technology,so as to provoke their attention and encourage interdisciplinary integration and industry-academia collaborative research.展开更多
Automotive brake rotors are commonly made from gray cast iron(GCI).During usage,brake rotors are gradually worn off and periodically replaced.Currently,replaced brake rotors are mostly remelted to produce brand-new ca...Automotive brake rotors are commonly made from gray cast iron(GCI).During usage,brake rotors are gradually worn off and periodically replaced.Currently,replaced brake rotors are mostly remelted to produce brand-new cast iron products,resulting in a relatively high energy consumption and carbon footprint into the environment.In addition,automotive brakes emit airborne particles.Some of the emitted particles are categorized as ultrafine,which are sized below 100 nm,leading to a series of health and environmental impacts.In this study,two surface treatment techniques are applied,ie.,high-velocity oxygen fuel(HVOF)and laser cladding(LC),to overlay wear-resistant coatings on conventional GCI brake rotors in order to refurbish the replaced GCI brake rotor and to avoid the remelting procedure.The two coating materials are evaluated in terms of their coefficient of friction(CoF),wear,and ultrafine particle emissions,by comparing them with a typical GCI brake rotor.The results show that the CoF of the HVOF disc is higher than those of the GCI and LC discs.Meanwhile,HVOF disc has the lowest wear rate but results in the highest wear rate on the mating brake pad material.The LC disc yields a similar wear rate as the GCI disc.The ultrafine particles from the GCI and LC discs appeared primarily in round,chunky,and flake shapes.The HVOF disc emits unique needle-shaped particles.In the ultrafine particle range,the GCI and HVOF discs generate particles that are primarily below 100 nm in the running-in period and 200 nm in the steady state.Meanwhile,the LC disc emitted particles that are primarily~200 nm in the entire test run.展开更多
Developing filtration media for particulate matter(PM)removal has been proven to be extremely challenging.Here,we report a facile and scalable strategy to fabricate a multi-level structured polyacrylonitrile/graphene ...Developing filtration media for particulate matter(PM)removal has been proven to be extremely challenging.Here,we report a facile and scalable strategy to fabricate a multi-level structured polyacrylonitrile/graphene oxide(PAN/GO)air filtration membrane to remove ultrafine particles in air by combining multi-jet electrospinning and physical bonding.Our approach allows the thin PAN nanofibers and two-dimensional GO nanosheets to form interpenetrating bonding structures on non-woven fabric and to assemble into stable filtration media.The resultant composite membranes can filtrate 300 nm particles with a high removal efficiency of 98.8%,a low pressure drop of 55 Pa,and a desirable quality factor of 0.34 Pa^(-1).This multi-level PAN/GO filter is expected to have wider applications not only for the ultrafine particle filtration and separation but also for the design of three-dimensional functional structures in the future.展开更多
Ultrafine γ-A12O3 particles are synthesized in Triton X- 10 0/n - hexanol/cycloh exan e/wat er water in o if(w/o )Inicroemulsion by mixing two separately prepared microemulsions containing Al(NO)3 and (Wb)ZCO, respec...Ultrafine γ-A12O3 particles are synthesized in Triton X- 10 0/n - hexanol/cycloh exan e/wat er water in o if(w/o )Inicroemulsion by mixing two separately prepared microemulsions containing Al(NO)3 and (Wb)ZCO, respectively.The ultrafine Al2O3 particles are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD)and their size and distribution are measured. The effects of water, surfactallt and reactant concentrations on the particlesize and distribution are studied. The results show that the particle size and distribution can be changed by varying thepreparation conditions, and the size of the microemulsion droplets has a controlling effect on the size of the pafticles. A. possible mechanism of ultrafine particles (UFPs) prepared by microemulsions is proposed.展开更多
Ultrafine particles represent a growing concern in the public health community but their precise role in many illnesses is still unknown. This lack of knowledge is related to the experimental difficulty in linking the...Ultrafine particles represent a growing concern in the public health community but their precise role in many illnesses is still unknown. This lack of knowledge is related to the experimental difficulty in linking their biological effects to their multiple properties, which are important determinants of toxicity. Our aim is to propose an interdisciplinary approach to study fine(FP) and ultrafine(UFP) particles, generated in a controlled manner using a mini CAST(Combustion Aerosol Standard) soot generator used with two different operating conditions(CAST1 and CAST3). The chemical characterization was performed by an untargeted analysis using ultra-high resolution mass spectrometry. In conjunction with this approach, subsequent analysis by gas chromatography–mass spectrometry(GC–MS) was performed to identify polycyclic aromatic hydrocarbons(PAH). CAST1 enabled the generation of FP with a predominance of small PAH molecules, and CAST3 enabled the generation of UFP, which presented higher numbers of carbon atoms corresponding to larger PAH molecules. Healthy normal human bronchial epithelial(NHBE) cells differentiated at the air-liquid interface(ALI) were directly exposed to these freshly emitted FP and UFP. Expression of MUC5AC, FOXJ1, OCLN and ZOI as well as microscopic observation confirmed the ciliated pseudostratified epithelial phenotype. Study of the mass deposition efficiency revealed a difference between the two operating conditions, probably due to the morphological differences between the two categories of particles. We demonstrated that only NHBE cells exposed to CAST3 particles induced upregulation in the gene expression of IL-8 and NQO1. This approach offers new perspectives to study FP and UFP with stable and controlled properties.展开更多
In this article, we illustrated the preparation method of γ Al 2O 3 ultrafine particles. The particle size and morphology were decided by a transmission electron microscopy (TEM) and crystal patterns were determin...In this article, we illustrated the preparation method of γ Al 2O 3 ultrafine particles. The particle size and morphology were decided by a transmission electron microscopy (TEM) and crystal patterns were determined by an X ray diffractometer (XRD). γ Al 2O 3 ultrafine particles have ultra characters in physics and chemistry, and the hydrogen peroxide biosensors based on it display not only fast response and high sensitivity, but also good stability.展开更多
基金This project is supported by the Scientific Fund of Polymer Physics Laboratory,Institute of Chemistry,Chinese Academy of Sciences.
文摘Waterborne ultrafine particles of epoxy resin were prepared by phase inversion technique. The results of SEM revealed that the particles diameter was in the range of 50 to 100 nm and the effects on amount of water required at phase inversion point were also discussed.
基金financial support from ColcienciasColombia(Project 141180764164,Contract 815-2018)。
文摘Air pollution by particulate matter(PM)is one of the main threats to human health,particularly in large cities where pollution levels are continually exceeded.According to their source of emission,geography,and local meteorology,the pollutant particles vary in size and composition.These particles are conditioned to the aerodynamic diameter and thus classified as coarse(2.5–10μm),fine(0.1–2.5μm),and ultrafine(<0.1μm),where the degree of toxicity becomes greater for smaller particles.These particles can get into the lungs and translocate into vital organs due to their size,causing significant human health consequences.Besides,PM pollutants have been linked to respiratory conditions,genotoxic,mutagenic,and carcinogenic activity in human beings.This paper presents an overview of emission sources,physicochemical characteristics,collection and measurement methodologies,toxicity,and existing control mechanisms for ultrafine particles(UFPs)in the last fifteen years.
文摘Fluidized chemical vapor deposition (FCVD) technology was developed for coating SnO 2 thin film on ultrafine Al 2O 3 particles.Transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) analyses demonstrated that SnO 2 films with different structures were deposited through controlling the coating temperature, reactant concentration, etc .. Nanocrystalline SnO 2 film was formed at 572.15K by gas phase reaction of SnCl 4 and H 2O.Electron probe microanalyser (EPMA) and energy dispersive spectrometer (EDS) analyses indicated that the distribution of nanocrystalline SnO 2 over inner and outer part of the Al 2O 3 agglomerates was homogeneous.
文摘Ultrafine particles prepared by evaporating pure Fe in CH4 atmosphere using arc-dischargeheating method, were found to consist of Fe-C solid solution, γ-Fe and Fe3C phases. EfFect of annealing temperature on phase transformation and hyperfine interactions has been investigated by Mossbauer spectroscopy, X-ray diffraction (XRD), differential thermal analysis and thermogravimetry (DTA-TG), transmission electron microscopy (TEM), oxygen determination and vibrating sample magnetometer (VSM) measurements. It was observed that phase transformation of γ-Fe to α-Fe occurs during annealing in vacuum. The mechanism causing the change of hyperfine interactions with annealing temperature differs for Fe-C solution and interstitial compounds. DifFerence of hyperfine interactions of Fe-C solid solution in the starting sample and its annealed samples is ascribed to the improvement of activation of interstitial carbon atoms. Stress-relieving in structure of annealed Fe3C particle can result in a weak influence on hyperfine interactions. Parameters fitted to the Mossbauer spectra show the existence of superparamagnetism in all the samples. Absorbed and combined oxygen on particle surface of the starting sample were determined.
文摘The composition distribution in Fe50Pd50 alloy ultrafine particles prepared by inert gas condensation method was investigated in details by means of X-ray diffraction technique through deconvolution of the X-ray diffraction data. The microscopic composition distribution in the alloy UFP was identified, which is caused by nonuniformity of the melt, fractional distillation during the evaporation process and statistical fluctuation during nucleation and coalescence of the alloy particles. The composition distribution affects the properties of the alloy UFP
文摘A model for the size-dependent initial sintering temperature of ultrafine particles was established. The theoretical predictions for the size-dependent sintering temperatures of W, Ni and Ag ultrafine particles are consistent with available experimental
基金This work received funding support from CNPq(National Counsel of Technological and Scientific Development,process 404104/2013-4)CAPES(Coordination for the Improvement of Higher Education Personnel)and Araucária Foundation.
文摘The deposition of ultrafine particles, in the human respiratory tract, from four highly impacted megacities across the globe, was evaluated by using a pulmonary deposition model. It was found that, for the locations studied, an average of 62% of atmospheric particles was retained in the respiratory system. As expected, the model shows that smaller particles penetrate deeper in the airways. In addition, it’s shown that children are more susceptible than adults, retaining 8% more ultrafine particles.
文摘Ce0.6Zr0.4O2 solid solution ultrafine particle was prepared in the cyclohexane/water/OP-10/n-hexanol reversed microemulsion. The quasi-ternary phase diagram investigations showed that the system has narrow W/O type microemulison region, so it is the proper system to prepare Ce0.6Zr0.4O2 solid solution ultrafine particle. Some physical-chemical techniques such as TG/DTA, XRD, BET, and HRTEM are used to characterize the resultant powders. The results show that the fluorite cubic Ce0.6Zr0.4O2 solid solution is obtained at 400 ℃. The surface area is (146.7 m^2·g^-1), which is higher than the surface area for sol-gel prepared sample (59.5m^2·g^-1). HRTEM images indicated that the Ce0.6Zr0.4O2 solid solution ultrafine particle is well-crystallized, narrow size distribution, less agglomeration, within mean size of 5 -7 nm.
文摘Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measurements of the saturation magnetization and coercivity force. Both b.c.c and f.c.c phase exist within a wide range for Fe 100- x Ni x , while x ≤45. The effective magnetic anisotropy K e was measured by applying the law of approach to saturation. The value of K e decreases with an increase of Ni content. It is noticed that the strain anisotropy makes a large contribution to the magnetic anisotropy. The estimation of grain size leads to the determination of the single domain critical size and domain wall energy. The exchange stiffness and exchange integral deduced from the relationship between the effective magnetic anisotropy and domain wall energy are in agreement with that calculated by other methods.
基金financial support received from the National Natural Science Foundation of China (No.82173486)the Natural Sciences Foundation of Tianjin City of China (No.12JCYBJC19100)+1 种基金the Scientific Research Program of Tianjin Education Commission (No.2019KJ167)The Program of Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction (No.2021KLMS10)。
文摘Particulate pollution is a global risk factor that seriously threatens human health.Fine particles(FPs)and ultrafine particles(UFPs)have small particle diameters and large specific surface areas,which can easily adsorb metals,microorganisms and other pollutants.FPs and UFPs can enter the human body in multiple ways and can be easily and quickly absorbed by the cells,tissues and organs.In the body,the particles can induce oxidative stress,inflammatory response and apoptosis,furthermore causing great adverse effects.Epidemiological studies mainly take the population as the research object to study the distribution of diseases and health conditions in a specific population and to focus on the identification of influencing factors.However,the mechanism by which a substance harms the health of organisms is mainly demonstrated through toxicological studies.Combining epidemiological studies with toxicological studies will provide a more systematic and comprehensive understanding of the impact of PM on the health of organisms.In this review,the sources,compositions,and morphologies of FPs and UFPs are briefly introduced in the first part.The effects and action mechanisms of exposure to FPs and UFPs on the heart,lungs,brain,liver,spleen,kidneys,pancreas,gastrointestinal tract,joints and reproductive system are systematically summarized.In addition,challenges are further pointed out at the end of the paper.This work provides useful theoretical guidance and a strong experimental foundation for investigating and preventing the adverse effects of FPs and UFPs on human health.
基金the National Natural Science Foundation of China(NSFC21978234)for financial assistance in this project
文摘The development of ultrafine particles provided a new way to solve problems in the fields of energy,environment,and medicine,and had become one of the most promising technologies.Therefore,the application of ultrafine particles required the development of cleaner,greener,and more efficient preparation methods.The new freeze-dissolving technology has been applied in manufacturing of KHCO_(3)ultrafine particles,with an aqueous solution of 0.02-0.1 g KHCO_(3)/g water.Frozen ice particles were formed after dripping the solution into liquid nitrogen.The antisolvent ethanol was used to dissolve the ice spherical template at a temperature below 273.15 K,and the pre-formed KHCO_(3)ultrafine particles inside the ice template remained in the ethanol aqueous solution.The ice particles were put into the freeze dryer to isolate the ultrafine KHCO_(3)particles.Compared with the particles produced with traditional freeze-drying technology,the ultrafine powder/particles produced by the freeze-dissolving technology were smaller with narrower size distribution.The freeze-dissolving technology has demonstrated a much more sustainable and efficient manufacturing process than the traditional freeze-drying process.In addition,the influence of the concentrations of KHCO_(3)and the sizes of ice particles were investigated with the discussions of mechanisms.
基金funded by the National Key Research and Development Program of China(2019YFC1804503 to YX)the National Natural Science Foundation of China(82003414 to YX).
文摘Ambient particles severely threaten human health worldwide.Compared to larger particles,ultrafine particles(UFPs)are highly concentrated in ambient environments,have a larger specific surface area,and are retained for a longer time in the lung.Recent studies have found that they can be transported into various extra-pulmonary organs by crossing the air-blood barrier(ABB).Therefore,to understand the adverse effects of UFPs,it is crucial to thoroughly investigate their bio-distribution and clearance pathways in vivo after inhalation,as well as their toxicological mechanisms.This review highlights emerging evidence on the bio-distribution of UFPs in pulmonary and extra-pulmonary organs.It explores how UFPs penetrate the ABB,the blood-brain barrier(BBB),and the placental barrier(PB)and subsequently undergo clearance by the liver,kidney,or intestine.In addition,the potential underlying toxicological mechanisms of UFPs are summarized,providing fundamental insights into how UFPs induce adverse health effects.
文摘Fine and ultrafine particles possess great potential for industrial applications ascribed from their huge specific surface area and ability to provide good gas–solid contact.However,these powders are inherently cohesive,making it challenging to achieve smooth flow and fluidization.This challenge can be well-resolved by nanoparticle modulation(nano-modulation),where a small amount of nanoparticles is uniformly mixed with the cohesive fine/ultrafine powders.Through nano-modulation,the fluidization system of cohesive powders exhibits distinguishable minimum fluidization velocity,enlarged bed expansion ratio(particularly the dense phase expansion),and scarcer,smaller,and slower moving bubbles,indicating improved flow and fluidization quality.The purpose of the current work is to systematically summarize the state-of-the-art progress in the fluidization and utilization of fine and ultrafine particles via the nanoparticle modulation method.Accordingly,a broader audience can be enlightened regarding this promising fine/ultrafine particle fluidization technology,so as to provoke their attention and encourage interdisciplinary integration and industry-academia collaborative research.
基金The authors are grateful for the financial support from FORMAS:Swedish Research Council for Sustainable Development(No.2020-02302)(Nescup project)The research also received funding from European Union's Horizon 2020 research and innovation programme(No.954377)(nPETS project).
文摘Automotive brake rotors are commonly made from gray cast iron(GCI).During usage,brake rotors are gradually worn off and periodically replaced.Currently,replaced brake rotors are mostly remelted to produce brand-new cast iron products,resulting in a relatively high energy consumption and carbon footprint into the environment.In addition,automotive brakes emit airborne particles.Some of the emitted particles are categorized as ultrafine,which are sized below 100 nm,leading to a series of health and environmental impacts.In this study,two surface treatment techniques are applied,ie.,high-velocity oxygen fuel(HVOF)and laser cladding(LC),to overlay wear-resistant coatings on conventional GCI brake rotors in order to refurbish the replaced GCI brake rotor and to avoid the remelting procedure.The two coating materials are evaluated in terms of their coefficient of friction(CoF),wear,and ultrafine particle emissions,by comparing them with a typical GCI brake rotor.The results show that the CoF of the HVOF disc is higher than those of the GCI and LC discs.Meanwhile,HVOF disc has the lowest wear rate but results in the highest wear rate on the mating brake pad material.The LC disc yields a similar wear rate as the GCI disc.The ultrafine particles from the GCI and LC discs appeared primarily in round,chunky,and flake shapes.The HVOF disc emits unique needle-shaped particles.In the ultrafine particle range,the GCI and HVOF discs generate particles that are primarily below 100 nm in the running-in period and 200 nm in the steady state.Meanwhile,the LC disc emitted particles that are primarily~200 nm in the entire test run.
基金supported by Beijing Natural Science Foundation(2172027).
文摘Developing filtration media for particulate matter(PM)removal has been proven to be extremely challenging.Here,we report a facile and scalable strategy to fabricate a multi-level structured polyacrylonitrile/graphene oxide(PAN/GO)air filtration membrane to remove ultrafine particles in air by combining multi-jet electrospinning and physical bonding.Our approach allows the thin PAN nanofibers and two-dimensional GO nanosheets to form interpenetrating bonding structures on non-woven fabric and to assemble into stable filtration media.The resultant composite membranes can filtrate 300 nm particles with a high removal efficiency of 98.8%,a low pressure drop of 55 Pa,and a desirable quality factor of 0.34 Pa^(-1).This multi-level PAN/GO filter is expected to have wider applications not only for the ultrafine particle filtration and separation but also for the design of three-dimensional functional structures in the future.
文摘Ultrafine γ-A12O3 particles are synthesized in Triton X- 10 0/n - hexanol/cycloh exan e/wat er water in o if(w/o )Inicroemulsion by mixing two separately prepared microemulsions containing Al(NO)3 and (Wb)ZCO, respectively.The ultrafine Al2O3 particles are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD)and their size and distribution are measured. The effects of water, surfactallt and reactant concentrations on the particlesize and distribution are studied. The results show that the particle size and distribution can be changed by varying thepreparation conditions, and the size of the microemulsion droplets has a controlling effect on the size of the pafticles. A. possible mechanism of ultrafine particles (UFPs) prepared by microemulsions is proposed.
基金supported by ANSES (French Agency for Food,Environmental and Occupational Health and SafetyPUFBIO project,Grant number EST-2017-190)+5 种基金co-supported by the Regional Council of Normandy and the European Union in the framework of the ERDF-ESF (CellSTEM project)a PhD fellowship funded by ADEME(Agency for Ecological Transition)financed by the Labex SynOrg(ANR-11-LABX-0029)the European Regional Development Fund (ERDF HN0001343)Financial support from the National Fourier transform ion cyclotron resonance network (FR 3624 CNRS)the European Union’s Horizon 2020 Research Infrastructures program (grant agreement 731077).
文摘Ultrafine particles represent a growing concern in the public health community but their precise role in many illnesses is still unknown. This lack of knowledge is related to the experimental difficulty in linking their biological effects to their multiple properties, which are important determinants of toxicity. Our aim is to propose an interdisciplinary approach to study fine(FP) and ultrafine(UFP) particles, generated in a controlled manner using a mini CAST(Combustion Aerosol Standard) soot generator used with two different operating conditions(CAST1 and CAST3). The chemical characterization was performed by an untargeted analysis using ultra-high resolution mass spectrometry. In conjunction with this approach, subsequent analysis by gas chromatography–mass spectrometry(GC–MS) was performed to identify polycyclic aromatic hydrocarbons(PAH). CAST1 enabled the generation of FP with a predominance of small PAH molecules, and CAST3 enabled the generation of UFP, which presented higher numbers of carbon atoms corresponding to larger PAH molecules. Healthy normal human bronchial epithelial(NHBE) cells differentiated at the air-liquid interface(ALI) were directly exposed to these freshly emitted FP and UFP. Expression of MUC5AC, FOXJ1, OCLN and ZOI as well as microscopic observation confirmed the ciliated pseudostratified epithelial phenotype. Study of the mass deposition efficiency revealed a difference between the two operating conditions, probably due to the morphological differences between the two categories of particles. We demonstrated that only NHBE cells exposed to CAST3 particles induced upregulation in the gene expression of IL-8 and NQO1. This approach offers new perspectives to study FP and UFP with stable and controlled properties.
文摘In this article, we illustrated the preparation method of γ Al 2O 3 ultrafine particles. The particle size and morphology were decided by a transmission electron microscopy (TEM) and crystal patterns were determined by an X ray diffractometer (XRD). γ Al 2O 3 ultrafine particles have ultra characters in physics and chemistry, and the hydrogen peroxide biosensors based on it display not only fast response and high sensitivity, but also good stability.