Main observation and conclusion A single particle-based confocal laser scanning microscopy was developed for the visual detection of copper ions in confined space.A fluorescence microparticle,named AuNCs/ZIF-8,was syn...Main observation and conclusion A single particle-based confocal laser scanning microscopy was developed for the visual detection of copper ions in confined space.A fluorescence microparticle,named AuNCs/ZIF-8,was synthesized by coating gold nanoclusters(AuNCs)onto the outer surface of zeolitic imidazolate framework-8(ZIF-8).展开更多
It was presented the in situ observation of growth behavior and morphology of delta-ferrite as a function of solidification rate in an AISI304 stainless steel. The specimens have been solidified and observed using con...It was presented the in situ observation of growth behavior and morphology of delta-ferrite as a function of solidification rate in an AISI304 stainless steel. The specimens have been solidified and observed using confocal scanning laser microscopy (CSLM). The δ-phase always appears like cells on the sample surface when critical supercooling occurs, during which the L→δ transformation starts. The solid-liquid (S-L) interface is found to be finger shaped and has no faceted shape. γ phase appears among δ grains due to partitioning of Ni into the melt during solidification, when solidification rate is higher. The mergence of observed δ cells is possible for the steel sample cooled at 7.5℃/min. The formation of dendrites can be observed on the free surface of the steel sample cooled at 150℃/min. The size of solidified delta grains decreases from 120 to 20-80μm, and the volume fraction of solidified austenite increases with increase in solidification rate from 7.5 to 150℃/min. The relation between the tip radius of δ cell and its growth rate is deduced, and the results agree with the experimental values.展开更多
Bacillus thuringiensis(Bt)exhibits strong insecticidal activity and is harmless to non-target organisms such as human and animals.Bt becomes the most commonly used environment-friendly insecticidal microorganism.Howev...Bacillus thuringiensis(Bt)exhibits strong insecticidal activity and is harmless to non-target organisms such as human and animals.Bt becomes the most commonly used environment-friendly insecticidal microorganism.However,the insecticidal activities of different Bt strains variy significantly.Therefore,it is particularly important to compare the insecticidal activities of different strains and explore their insecticidal effector mechanisms to expand Bt insecticidal spectrum and enrich transgenic resources.Here,the insecticidal activities of Vip3Aa57 and Vip3Aa62 strains,carrying vegetative insecticidal protein-encoding genes that were inserted into the expression vector pET-21b and transformed into Escherichia coli Rosetta(DE3)strain,expressing 88 ku protein,were compared.Vip3Aa57 protein reportedly displayed body weight inhibition effect on Spodoptera exigua without affecting Heliothis armigera while Vip3Aa62 protein was known to have strong insecticidal activity against S.exigua(LC50=5.124 ng•mg^(-1)).A low H.armigera activity(LC50=870.1 ng•mg^(-1))was observed.The paraffin sectioning results showed that Vip3Aa57 protein affected S.exigua midgut cell morphology.The laser confocal microscopic imaging results showed that Vip3Aa57 bound to receptors in the midgut without damaging the midgut tissue morphology.This study would be conducive for making full use of Bt strains in the soil to compare the insecticidal activities of different Vip insecticidal genes.It could thus provide significant help in revealing the underlying insecticidal mechanisms of Vip3Aa insecticidal genes,developing new insecticidal proteins and delaying pest resistance problems.展开更多
Lithium aluminum titanium phosphate(LATP)is one of the materials under consideration as an electrolyte in future all-solid-state lithium-ion batteries.In ceramic processing,the presence of secondary phases and porosit...Lithium aluminum titanium phosphate(LATP)is one of the materials under consideration as an electrolyte in future all-solid-state lithium-ion batteries.In ceramic processing,the presence of secondary phases and porosity play an important role.In a presence of more than one secondary phase and pores,image analysis must tackle the difficulties about distinguishing between these microstructural features.In this study,we study the phase evolution of LATP ceramics sintered at temperatures between 950 and 1100℃by image segmentation based on energy-dispersive X-ray spectroscopy(EDS)elemental maps combined with quantitative analysis of LATP grains.We found aluminum phosphate(AlPO4)and another phosphate phase((Lix)PyOz).The amount of these phases changes with sintering temperature.First,since the grains act as an aluminum source for AlPO4 formation,the aluminum content in the LATP grains decreases.Second,the amount of secondary phase changes from more(Lix)PyOz at 950℃to mainly AlPO4 at 1100℃sintering temperature.We also used scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)to study the evolution of the LATP grains and AlPO4,and LATP grain size increases with sintering temperature.In addition,transmission electron microscopy(TEM)was used for the determination of grain boundary width and to identify the amorphous structure of AlPO4.展开更多
To investigate the dissolution behaviors of Al_(2)O_(3)inclusions in CaO-5wt%MgO-SiO_(2)-30wt%Al_(2)O_(3)-TiO_(2)system ladle slags,confocal scanning laser microscopy was conducted on the slags with different TiO_(2)c...To investigate the dissolution behaviors of Al_(2)O_(3)inclusions in CaO-5wt%MgO-SiO_(2)-30wt%Al_(2)O_(3)-TiO_(2)system ladle slags,confocal scanning laser microscopy was conducted on the slags with different TiO_(2)contents(0-10wt%),and scanning electron microscopy was performed to study the interfacial reaction between Al_(2)O_(3)and this slag system.The results disclose that the dissolution of Al_(2)O_(3)inclusions does not result in the formation of new phases at the boundary between the slag and the inclusions.In TiO_(2)-bearing and TiO_(2)-free ladle slags,there is no difference in the dissolution mechanism of Al_(2)O_(3)inclusions at steelmaking temperatures.Boundary layer diffusion is found as the controlling step of the dissolution of Al_(2)O_(3),and the diffusion coefficient is in the range of 4.18×10^(-10)to 2.18×10^(-9)m^(2)/s at 1450-1500℃.Compared with the solubility of Al_(2)O_(3)in the slags,slag viscosity and temperature play a more profound role in the dissolution of Al_(2)O_(3)inclusions.A lower viscosity and a lower melting point of the slags are beneficial for the dissolution.Suitable addition of TiO_(2)(e.g.,5wt%)in ladle slags can enhance the dissolution of Al_(2)O_(3)inclusions because of the low viscosity and melting point of the slags,while excessive addition of TiO_(2)(e.g.,10wt%)shows the opposite trend.展开更多
The corrosion behavior of cupronickel alloy immersed in the simulated seawater in or without the presence of sulfate-reducing bacteria(SRB)was studied.The results of scanning electronic microscopy and electrochemical ...The corrosion behavior of cupronickel alloy immersed in the simulated seawater in or without the presence of sulfate-reducing bacteria(SRB)was studied.The results of scanning electronic microscopy and electrochemical impedance spectra reveal that corrosion of the sample immersed in the simulated seawater with SRB was more serious than that immersed in the simulated seawater without SRB.The atomic force microscopy images show that after immersion for 15 days,the surface roughness of the sample in the simulated seawater with SRB was higher than that of the sample in the simulated seawater without SRB.The analysis of confocal laser scanning microscopy indicates that the average depth of the pits on the surface of the sample in the simulated seawater with SRB was almost twice deeper than that of the sample in the simulated seawater without SRB.展开更多
To investigate the effect of surface-modified nanoparticles(NPs)on the inclusion refinement and microstructure evolution,deoxidized experiment ingots with different amounts of modified NPs were manufactured under diff...To investigate the effect of surface-modified nanoparticles(NPs)on the inclusion refinement and microstructure evolution,deoxidized experiment ingots with different amounts of modified NPs were manufactured under different cooling conditions.Laser scanning confocal microscope(LSCM)was hereby used for in-situ observation of the phase transition and microstructural evolution during heat cycle process.The results revealed that the inclusion size was always smaller under water quenching than under air cooling,and the number of inclusions was greater under water quenching.After NP addition,the nucleant inclusions were identified as MgAl_(2)O_(4)spinel and irregular TiN inclusion from SEM-EDS measurement and equilibrium calculations using Factsage thermodynamic software.The higher cooling rate under water quenching resulted in less polygonal ferrite decrease and the formation of bainite in the steel.The LSCM experiments showed that ferrite side plates(FSP)always formed on the boundary prior to the formation of acicular ferrite(AF)on the intragranular inclusions,and the start transformation temperatures of FSP and AF phases both lowered after NP addition.The higher cooling rate and NP addition contributed to AF formation and increased the degree of interlocking of the AF phase.Finally,the relationship between the characteristics of inclusions and the kinetics of AF was investigated.展开更多
A recombinant gene expressing a Cry1Ac-GFP fusion protein with a molecular mass of approximately 160 kD was constructed to investigate the expression of cry1Ac,the localization of its gene product Cry1Ac,and its role ...A recombinant gene expressing a Cry1Ac-GFP fusion protein with a molecular mass of approximately 160 kD was constructed to investigate the expression of cry1Ac,the localization of its gene product Cry1Ac,and its role in crystal development in Bacillus thuringiensis.The cry1Ac-gfp fusion gene under the control of the cry1Ac promoter was cloned into the plasmid pHT304,and this construct was designated pHTcry1Ac-gfp.pHTcry1Ac-gfp was transformed into the crystal-negative strain,HD-73 cry-,and the resulting strain was named HD-73-(pHTcry1Ac-gfp).The gfp gene was then inserted into the large HD-73 endogenous plasmid pHT73 and fused with the 3' terminal of the cry1Ac gene by homologous recombination,yielding HD-73Φ(cry1Ac-gfp)3534.Laser confocal microscopy and Western blot analyses showed for the first time that the Cry1Ac-GFP fusion proteins in both HD-73-(pHTcry1Ac-gfp) and HD-73Φ(cry1Ac-gfp)3534 were produced during asymmetric septum formation.Surprisingly,the Cry1Ac-GFP fusion protein showed polarity and was located near the septa in both strains.There was no significant difference between Cry1Ac-GFP and Cry1Ac in their toxicity to Plutella xylostella larvae.展开更多
基金This work is supported by the National Natural Science Foundation of China(Nos.21775097 and 21775098)the Fundamental Research Funds for the Central Universities(No.2017TS021).
文摘Main observation and conclusion A single particle-based confocal laser scanning microscopy was developed for the visual detection of copper ions in confined space.A fluorescence microparticle,named AuNCs/ZIF-8,was synthesized by coating gold nanoclusters(AuNCs)onto the outer surface of zeolitic imidazolate framework-8(ZIF-8).
基金This work was supported by the China Postdoctoral Science Foundation (No. 20060390150).
文摘It was presented the in situ observation of growth behavior and morphology of delta-ferrite as a function of solidification rate in an AISI304 stainless steel. The specimens have been solidified and observed using confocal scanning laser microscopy (CSLM). The δ-phase always appears like cells on the sample surface when critical supercooling occurs, during which the L→δ transformation starts. The solid-liquid (S-L) interface is found to be finger shaped and has no faceted shape. γ phase appears among δ grains due to partitioning of Ni into the melt during solidification, when solidification rate is higher. The mergence of observed δ cells is possible for the steel sample cooled at 7.5℃/min. The formation of dendrites can be observed on the free surface of the steel sample cooled at 150℃/min. The size of solidified delta grains decreases from 120 to 20-80μm, and the volume fraction of solidified austenite increases with increase in solidification rate from 7.5 to 150℃/min. The relation between the tip radius of δ cell and its growth rate is deduced, and the results agree with the experimental values.
基金Supported by the National Key R&D Projects(2017YFD0201200)。
文摘Bacillus thuringiensis(Bt)exhibits strong insecticidal activity and is harmless to non-target organisms such as human and animals.Bt becomes the most commonly used environment-friendly insecticidal microorganism.However,the insecticidal activities of different Bt strains variy significantly.Therefore,it is particularly important to compare the insecticidal activities of different strains and explore their insecticidal effector mechanisms to expand Bt insecticidal spectrum and enrich transgenic resources.Here,the insecticidal activities of Vip3Aa57 and Vip3Aa62 strains,carrying vegetative insecticidal protein-encoding genes that were inserted into the expression vector pET-21b and transformed into Escherichia coli Rosetta(DE3)strain,expressing 88 ku protein,were compared.Vip3Aa57 protein reportedly displayed body weight inhibition effect on Spodoptera exigua without affecting Heliothis armigera while Vip3Aa62 protein was known to have strong insecticidal activity against S.exigua(LC50=5.124 ng•mg^(-1)).A low H.armigera activity(LC50=870.1 ng•mg^(-1))was observed.The paraffin sectioning results showed that Vip3Aa57 protein affected S.exigua midgut cell morphology.The laser confocal microscopic imaging results showed that Vip3Aa57 bound to receptors in the midgut without damaging the midgut tissue morphology.This study would be conducive for making full use of Bt strains in the soil to compare the insecticidal activities of different Vip insecticidal genes.It could thus provide significant help in revealing the underlying insecticidal mechanisms of Vip3Aa insecticidal genes,developing new insecticidal proteins and delaying pest resistance problems.
文摘Lithium aluminum titanium phosphate(LATP)is one of the materials under consideration as an electrolyte in future all-solid-state lithium-ion batteries.In ceramic processing,the presence of secondary phases and porosity play an important role.In a presence of more than one secondary phase and pores,image analysis must tackle the difficulties about distinguishing between these microstructural features.In this study,we study the phase evolution of LATP ceramics sintered at temperatures between 950 and 1100℃by image segmentation based on energy-dispersive X-ray spectroscopy(EDS)elemental maps combined with quantitative analysis of LATP grains.We found aluminum phosphate(AlPO4)and another phosphate phase((Lix)PyOz).The amount of these phases changes with sintering temperature.First,since the grains act as an aluminum source for AlPO4 formation,the aluminum content in the LATP grains decreases.Second,the amount of secondary phase changes from more(Lix)PyOz at 950℃to mainly AlPO4 at 1100℃sintering temperature.We also used scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)to study the evolution of the LATP grains and AlPO4,and LATP grain size increases with sintering temperature.In addition,transmission electron microscopy(TEM)was used for the determination of grain boundary width and to identify the amorphous structure of AlPO4.
基金financially supported by the National Natural Science Foundation of China(Nos.U20A20272 and52074073)the Fundamental Research Funds for the Central Universities(No.2325035)。
文摘To investigate the dissolution behaviors of Al_(2)O_(3)inclusions in CaO-5wt%MgO-SiO_(2)-30wt%Al_(2)O_(3)-TiO_(2)system ladle slags,confocal scanning laser microscopy was conducted on the slags with different TiO_(2)contents(0-10wt%),and scanning electron microscopy was performed to study the interfacial reaction between Al_(2)O_(3)and this slag system.The results disclose that the dissolution of Al_(2)O_(3)inclusions does not result in the formation of new phases at the boundary between the slag and the inclusions.In TiO_(2)-bearing and TiO_(2)-free ladle slags,there is no difference in the dissolution mechanism of Al_(2)O_(3)inclusions at steelmaking temperatures.Boundary layer diffusion is found as the controlling step of the dissolution of Al_(2)O_(3),and the diffusion coefficient is in the range of 4.18×10^(-10)to 2.18×10^(-9)m^(2)/s at 1450-1500℃.Compared with the solubility of Al_(2)O_(3)in the slags,slag viscosity and temperature play a more profound role in the dissolution of Al_(2)O_(3)inclusions.A lower viscosity and a lower melting point of the slags are beneficial for the dissolution.Suitable addition of TiO_(2)(e.g.,5wt%)in ladle slags can enhance the dissolution of Al_(2)O_(3)inclusions because of the low viscosity and melting point of the slags,while excessive addition of TiO_(2)(e.g.,10wt%)shows the opposite trend.
基金financial support from National Basic Research Program of China (No.2014CB643304)the Key Technology of Corrosion Control on Wind Power Equipment Academician Workstation Project (No.2013B090400023)the National Natural Science Foundation of China (Grant No.51571202)
文摘The corrosion behavior of cupronickel alloy immersed in the simulated seawater in or without the presence of sulfate-reducing bacteria(SRB)was studied.The results of scanning electronic microscopy and electrochemical impedance spectra reveal that corrosion of the sample immersed in the simulated seawater with SRB was more serious than that immersed in the simulated seawater without SRB.The atomic force microscopy images show that after immersion for 15 days,the surface roughness of the sample in the simulated seawater with SRB was higher than that of the sample in the simulated seawater without SRB.The analysis of confocal laser scanning microscopy indicates that the average depth of the pits on the surface of the sample in the simulated seawater with SRB was almost twice deeper than that of the sample in the simulated seawater without SRB.
基金The Chinese Scholarship Council(CSC)financially supported by the National Natural Science Foundation of China(Nos.51874024 and 51734003)the Fundamental Research Funds for the Central Universities(No.FRF-TP-18–009C1)
文摘To investigate the effect of surface-modified nanoparticles(NPs)on the inclusion refinement and microstructure evolution,deoxidized experiment ingots with different amounts of modified NPs were manufactured under different cooling conditions.Laser scanning confocal microscope(LSCM)was hereby used for in-situ observation of the phase transition and microstructural evolution during heat cycle process.The results revealed that the inclusion size was always smaller under water quenching than under air cooling,and the number of inclusions was greater under water quenching.After NP addition,the nucleant inclusions were identified as MgAl_(2)O_(4)spinel and irregular TiN inclusion from SEM-EDS measurement and equilibrium calculations using Factsage thermodynamic software.The higher cooling rate under water quenching resulted in less polygonal ferrite decrease and the formation of bainite in the steel.The LSCM experiments showed that ferrite side plates(FSP)always formed on the boundary prior to the formation of acicular ferrite(AF)on the intragranular inclusions,and the start transformation temperatures of FSP and AF phases both lowered after NP addition.The higher cooling rate and NP addition contributed to AF formation and increased the degree of interlocking of the AF phase.Finally,the relationship between the characteristics of inclusions and the kinetics of AF was investigated.
基金supported by the National Basic Research Program of China (Grant No. 2009CB118902)the National High-Tech Research and Development Program of China (Grant No. 2006AA10A212)
文摘A recombinant gene expressing a Cry1Ac-GFP fusion protein with a molecular mass of approximately 160 kD was constructed to investigate the expression of cry1Ac,the localization of its gene product Cry1Ac,and its role in crystal development in Bacillus thuringiensis.The cry1Ac-gfp fusion gene under the control of the cry1Ac promoter was cloned into the plasmid pHT304,and this construct was designated pHTcry1Ac-gfp.pHTcry1Ac-gfp was transformed into the crystal-negative strain,HD-73 cry-,and the resulting strain was named HD-73-(pHTcry1Ac-gfp).The gfp gene was then inserted into the large HD-73 endogenous plasmid pHT73 and fused with the 3' terminal of the cry1Ac gene by homologous recombination,yielding HD-73Φ(cry1Ac-gfp)3534.Laser confocal microscopy and Western blot analyses showed for the first time that the Cry1Ac-GFP fusion proteins in both HD-73-(pHTcry1Ac-gfp) and HD-73Φ(cry1Ac-gfp)3534 were produced during asymmetric septum formation.Surprisingly,the Cry1Ac-GFP fusion protein showed polarity and was located near the septa in both strains.There was no significant difference between Cry1Ac-GFP and Cry1Ac in their toxicity to Plutella xylostella larvae.
