Exchange bias effect has been widely employed for various magnetic devices.The experimentally reported magnitude of exchange bias field is often smaller than that predicted theoretically,which is considered to be due ...Exchange bias effect has been widely employed for various magnetic devices.The experimentally reported magnitude of exchange bias field is often smaller than that predicted theoretically,which is considered to be due to the partly pinned spins of ferromagnetic layer by antiferromagnetic layer.However,mapping the distribution of pinned spins is challenging.In this work,we directly image the reverse domain nucleation and domain wall movement process in the exchange biased Co Fe B/Ir Mn bilayers by Lorentz transmission electron microscopy.From the in-situ experiments,we obtain the distribution mapping of the pinning strength,showing that only 1/6 of the ferromagnetic layer at the interface is strongly pinned by the antiferromagnetic layer.Our results prove the existence of an inhomogeneous pinning effect in exchange bias systems.展开更多
We measured the intrinsic electrophoretic drag coefficient of a single charged particle by optically trapping the particle and applying an AC electric field,and found it to be markedly different from that of the Stoke...We measured the intrinsic electrophoretic drag coefficient of a single charged particle by optically trapping the particle and applying an AC electric field,and found it to be markedly different from that of the Stokes drag.The drag coefficient,along with the measured electrical force,yield a mobility-zeta potential relation that agrees with the literature.By using the measured mobility as input,numerical calculations based on the Poisson-Nernst-Planck equations,coupled to the Navier-Stokes equation,reveal an intriguing microscopic electroosmotic flow near the particle surface,with a well-defined transition between an inner flow field and an outer flow field in the vicinity of electric double layer’s outer boundary.This distinctive interface delineates the surface that gives the correct drag coefficient and the effective electric charge.The consistency between experiments and theoretical predictions provides new insights into the classic electrophoresis problem,and can shed light on new applications of electrophoresis to investigate biological nanoparticles.展开更多
Interfaces define the bulk.It is widely known that many interesting phenomena occur at the interfaces separating two homogeneous phases of matter.In this opinion piece,I wish to call attention to two recent developmen...Interfaces define the bulk.It is widely known that many interesting phenomena occur at the interfaces separating two homogeneous phases of matter.In this opinion piece,I wish to call attention to two recent developments that involve at least one interface.The first development is in desalination-a topic of practical importance in view of the steadily eroding global freshwater supply.The second development involves the use of hydrodynamic eigenmodes to not only determine the position of the hydrodynamic boundary in channel flows-a somewhat surprising proposition,since that position does not coincide with the solid/liquid interface-but also obtain an alternative perspective on thermal fluctuations and their linkage to hydrodynamic boundary conditions in a mesoscopic channel.展开更多
We revisit the classical problem of granular hopping conduction＇s σ∝exp[-（To/T）1/2] temperature dependence, where a denotes conductivity, T is temperature, and To is a sample-dependent constant. By using the hopp...We revisit the classical problem of granular hopping conduction＇s σ∝exp[-（To/T）1/2] temperature dependence, where a denotes conductivity, T is temperature, and To is a sample-dependent constant. By using the hopping conduction formulation in conjunction with the incorporation of the random potential that has been shown to exist in insulator-conductor composites, it is demonstrated that the widely observed temperature dependence of granular hopping conduction emerges very naturally through the immediate-neighbor critical-path argument. Here, immediate-neighbor pairs are defined to be those where a line connecting two grains does not cross or by-pass other grains, and the critical-path argument denotes the derivation of sample conductance based on the geometric percolation condition that is marked by the critical conduction path in a random granular composite. Simulations based on the exact electrical network evaluation of finite-sample conductance show that the configuration- averaged results agree well with those obtained using the immediate-neighbor critical-path method. Furthermore, the results obtained using both these methods show good agreement with experimental data on hopping conduction in a sputtered metal-insulator composite Agx（SnO2）1-x, where x denotes the metal volume fraction. The present approach offers a relatively straightforward and simple expla- nation for the temperature behavior that has been widely observed over diverse material systems, but which has remained a puzzle in spite of the various efforts made to explain this phenomenon.展开更多
From the hindgut contents of Holotrichia parallela larvae,207 aerobic and facultatively anaerobic cellulolytic bacterial isolates were obtained.These bacterial isolates were assigned to 21 genotypes by amplified ribos...From the hindgut contents of Holotrichia parallela larvae,207 aerobic and facultatively anaerobic cellulolytic bacterial isolates were obtained.These bacterial isolates were assigned to 21 genotypes by amplified ribosomal DNA restriction analysis(ARDRA).A partial 16 S rDNA sequence analysis and standard biochemical and physiological tests were used for the assignment of the 21 representative isolates.Our results show that the cellulolytic bacterial community is dominated by the Proteobacteria(70.05%),followed by the Actinobacteria(24.15%),the Firmicutes(4.35%),and the Bacteroidetes(1.45%).And among the cellulolytic bacteria,some isolates,Siphonobacter aquaeclarae,Cellulosimicrobium funkei,Citrobacter freundii,Pseudomonas nitroreducens,and so on,are reported to be cellulolytic for the first time in this study.Among these isolates,a novel bacterium,designated Pseudomonas sp.HP207,with the highest endoglucanase productivity was selected for further study.The production of the endoglucanase was optimized by varying various physical culture conditions using a submerged fermentation method.Under the optimized fermentation conditions,the maximum endoglucanase activity of 1.432 U mL-1 in bacterial cultures was obtained,higher than those of the most widely studied bacteria and fungi,which are the attractive candidates for the commercial producer of cellulase.And the crude endoglucanase enzyme was also highly thermostable;approximately 55% of the original activity was maintained after pretreatment at 70°C for 1 h.Thus,from the present study,the bacterium can be added up to the database of cellulolytic bacteria,the scarab gut is an attractive source for the study of novel cellulolytic microorganisms and enzymes useful for cellulose degradation.展开更多
Flexible electronic devices are highly attractive for a variety of applications such as flexible circuit boards, solar cells, paper-like displays, and sensitive skin, due to their stretchable, biocompatible, light-wei...Flexible electronic devices are highly attractive for a variety of applications such as flexible circuit boards, solar cells, paper-like displays, and sensitive skin, due to their stretchable, biocompatible, light-weight,portable, and low cost properties. Due to magnetic devices being important parts of electronic devices, it is essential to study the magnetic properties of magnetic thin films and devices fabricated on flexible substrates. In this review, we mainly introduce the recent progress in flexible magnetic thin films and devices, including the study on the stress-dependent magnetic properties of magnetic thin films and devices, and controlling the properties of flexible magnetic films by stress-related multi-fields, and the design and fabrication of flexible magnetic devices.展开更多
Human Neurobeachin-like 1(NBEAL1)gene was an important member of BEACH-WD40 domain family,which was confirmed to be overexpressed in I stage glioma.In this study,we extracted total RNAs from U251 cell line,acquired it...Human Neurobeachin-like 1(NBEAL1)gene was an important member of BEACH-WD40 domain family,which was confirmed to be overexpressed in I stage glioma.In this study,we extracted total RNAs from U251 cell line,acquired its cDNA sequence by RT-PCR,and cloned part of NBEAL1 cDNA fragments into the vector pGEX-KG.The recombinant expression vector achieved high expression in E.coli BL21 as a GST fusion protein.NBEAL1 recombinant protein was purified by affinity chromatography.Monoclonal antibody was prepared against the recombinant NBEAL1 protein.Its bioactivity was identified by Western Blotting analysis.Anti-NBEAL1 antibody was conjugated with CdTe quantum dots.Resultant anti-NBEAL1 antibody-conjugated nanoprobes were injected into mice via tail vessel.After 12h,it is clearly observed that prepared nanoprobes located in brain tissues of mice model with glioma by IVIS Imaging system.In conclusion,NBEAL1 protein was successfully expressed and its monoclonal antibody was successfully prepared.Anti-NBEAL1 antibody-conjugated quantum dots may be used to image glioma.These prepared nanoprobes have great potential in early detection of glioma.展开更多
There were no reports on the anti-inflammatory effect of the seed of C.camphora(CCS)and the changes in the process of processing and consumption.The aim of the study was to investigate the anti-inflammatory activity o...There were no reports on the anti-inflammatory effect of the seed of C.camphora(CCS)and the changes in the process of processing and consumption.The aim of the study was to investigate the anti-inflammatory activity of CCS ethanol extracts(EE),and the changes of it after simulated gastrointestinal digestion and alkaline hydrolysis in a lipopolysaccharide(LPS)-induced inflammatory macrophages model in vitro.The phytochemical charac-teristics of EE,digested ethanol extracts(dEE)and hydrolysed ethanol extracts(hEE)were analyzed using UPLCLTQOrbitrap-MS/MS in this study,and 17 chemicals were tentatively identified from the three prepared sam-ples.EE,dEE and hEE may have cell protection function,and both of them exhibited strong anti-inflammatory activity as significantly reduced multiple pro-inflammatory mediators and cytokines secretion and expression.Although the anti-inflammatory activity of EE was decreased by digestion and hydrolysis,and hydrolysis had more negative effect than digestion,most of its anti-inflammatory activity was retained.The mitigation of inflammation of EE may be by suppressing phosphorylation levels of signaling molecules of nuclear factor kappa B(NF-κB)and mitogen-activated protein kinases(MAPKs)signaling pathways.The results suggest that the anti-inflammatory activity of EE is relatively stable undergo gastrointestinal digestion and alkaline hydrolysis,which may facilitate the processing and consumption of related products.展开更多
The no-slip boundary condition,i.e.,zero fluid velocity relative to the solid at the fluid-solid interface,has been very successful in describing many macroscopic flows.A problem of principle arises when the no-slip b...The no-slip boundary condition,i.e.,zero fluid velocity relative to the solid at the fluid-solid interface,has been very successful in describing many macroscopic flows.A problem of principle arises when the no-slip boundary condition is used to model the hydrodynamics of immiscible-fluid displacement in the vicinity of the moving contact line,where the interface separating two immiscible fluids intersects the solid wall.Decades ago it was already known that the moving contact line is incompatible with the no-slip boundary condition,since the latter would imply infinite dissipation due to a non-integrable singularity in the stress near the contact line.In this paper we first present an introductory review of the problem.We then present a detailed review of our recent results on the contact-line motion in immiscible two-phase flow,from molecular dynamics(MD)simulations to continuum hydrodynamics calculations.Through extensive MD studies and detailed analysis,we have uncovered the slip boundary condition governing the moving contact line,denoted the generalized Navier boundary condition.We have used this discovery to formulate a continuum hydrodynamic model whose predictions are in remarkable quantitative agreement with the MD simulation results down to the molecular scale.These results serve to affirm the validity of the generalized Navier boundary condition,as well as to open up the possibility of continuum hydrodynamic calculations of immiscible flows that are physically meaningful at the molecular level.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0201102)the National Natural Science Foundation of China(Grant No.51571208)+3 种基金the Instrument Developing Project of Chinese Academy of Sciences(Grant No.YZ201536)the Program for Key Science and Technology Innovation Team of Zhejiang Province,China(Grant No.2013TD08)the K C Wong Education Foundation(Grant No.rczx0800)the K C Wong Magna Fund in Ningbo University
文摘Exchange bias effect has been widely employed for various magnetic devices.The experimentally reported magnitude of exchange bias field is often smaller than that predicted theoretically,which is considered to be due to the partly pinned spins of ferromagnetic layer by antiferromagnetic layer.However,mapping the distribution of pinned spins is challenging.In this work,we directly image the reverse domain nucleation and domain wall movement process in the exchange biased Co Fe B/Ir Mn bilayers by Lorentz transmission electron microscopy.From the in-situ experiments,we obtain the distribution mapping of the pinning strength,showing that only 1/6 of the ferromagnetic layer at the interface is strongly pinned by the antiferromagnetic layer.Our results prove the existence of an inhomogeneous pinning effect in exchange bias systems.
文摘We measured the intrinsic electrophoretic drag coefficient of a single charged particle by optically trapping the particle and applying an AC electric field,and found it to be markedly different from that of the Stokes drag.The drag coefficient,along with the measured electrical force,yield a mobility-zeta potential relation that agrees with the literature.By using the measured mobility as input,numerical calculations based on the Poisson-Nernst-Planck equations,coupled to the Navier-Stokes equation,reveal an intriguing microscopic electroosmotic flow near the particle surface,with a well-defined transition between an inner flow field and an outer flow field in the vicinity of electric double layer’s outer boundary.This distinctive interface delineates the surface that gives the correct drag coefficient and the effective electric charge.The consistency between experiments and theoretical predictions provides new insights into the classic electrophoresis problem,and can shed light on new applications of electrophoresis to investigate biological nanoparticles.
文摘Interfaces define the bulk.It is widely known that many interesting phenomena occur at the interfaces separating two homogeneous phases of matter.In this opinion piece,I wish to call attention to two recent developments that involve at least one interface.The first development is in desalination-a topic of practical importance in view of the steadily eroding global freshwater supply.The second development involves the use of hydrodynamic eigenmodes to not only determine the position of the hydrodynamic boundary in channel flows-a somewhat surprising proposition,since that position does not coincide with the solid/liquid interface-but also obtain an alternative perspective on thermal fluctuations and their linkage to hydrodynamic boundary conditions in a mesoscopic channel.
文摘We revisit the classical problem of granular hopping conduction＇s σ∝exp[-（To/T）1/2] temperature dependence, where a denotes conductivity, T is temperature, and To is a sample-dependent constant. By using the hopping conduction formulation in conjunction with the incorporation of the random potential that has been shown to exist in insulator-conductor composites, it is demonstrated that the widely observed temperature dependence of granular hopping conduction emerges very naturally through the immediate-neighbor critical-path argument. Here, immediate-neighbor pairs are defined to be those where a line connecting two grains does not cross or by-pass other grains, and the critical-path argument denotes the derivation of sample conductance based on the geometric percolation condition that is marked by the critical conduction path in a random granular composite. Simulations based on the exact electrical network evaluation of finite-sample conductance show that the configuration- averaged results agree well with those obtained using the immediate-neighbor critical-path method. Furthermore, the results obtained using both these methods show good agreement with experimental data on hopping conduction in a sputtered metal-insulator composite Agx（SnO2）1-x, where x denotes the metal volume fraction. The present approach offers a relatively straightforward and simple expla- nation for the temperature behavior that has been widely observed over diverse material systems, but which has remained a puzzle in spite of the various efforts made to explain this phenomenon.
文摘From the hindgut contents of Holotrichia parallela larvae,207 aerobic and facultatively anaerobic cellulolytic bacterial isolates were obtained.These bacterial isolates were assigned to 21 genotypes by amplified ribosomal DNA restriction analysis(ARDRA).A partial 16 S rDNA sequence analysis and standard biochemical and physiological tests were used for the assignment of the 21 representative isolates.Our results show that the cellulolytic bacterial community is dominated by the Proteobacteria(70.05%),followed by the Actinobacteria(24.15%),the Firmicutes(4.35%),and the Bacteroidetes(1.45%).And among the cellulolytic bacteria,some isolates,Siphonobacter aquaeclarae,Cellulosimicrobium funkei,Citrobacter freundii,Pseudomonas nitroreducens,and so on,are reported to be cellulolytic for the first time in this study.Among these isolates,a novel bacterium,designated Pseudomonas sp.HP207,with the highest endoglucanase productivity was selected for further study.The production of the endoglucanase was optimized by varying various physical culture conditions using a submerged fermentation method.Under the optimized fermentation conditions,the maximum endoglucanase activity of 1.432 U mL-1 in bacterial cultures was obtained,higher than those of the most widely studied bacteria and fungi,which are the attractive candidates for the commercial producer of cellulase.And the crude endoglucanase enzyme was also highly thermostable;approximately 55% of the original activity was maintained after pretreatment at 70°C for 1 h.Thus,from the present study,the bacterium can be added up to the database of cellulolytic bacteria,the scarab gut is an attractive source for the study of novel cellulolytic microorganisms and enzymes useful for cellulose degradation.
基金supported by the National Key R&D Program of China(No.2016YFA0201102)the National Natural Science Foundation of China(Nos.51571208,51301191,51525103,11274321,11474295,51401230)+4 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2016270)the Key Research Program of the Chinese Academy of Sciences(No.KJZD-EW-M05)the Ningbo Major Project for Science and Technology(No.2014B11011)the Ningbo Science and Technology Innovation Team(No.2015B11001)and the Ningbo Natural Science Foundation(No.2015A610110)
文摘Flexible electronic devices are highly attractive for a variety of applications such as flexible circuit boards, solar cells, paper-like displays, and sensitive skin, due to their stretchable, biocompatible, light-weight,portable, and low cost properties. Due to magnetic devices being important parts of electronic devices, it is essential to study the magnetic properties of magnetic thin films and devices fabricated on flexible substrates. In this review, we mainly introduce the recent progress in flexible magnetic thin films and devices, including the study on the stress-dependent magnetic properties of magnetic thin films and devices, and controlling the properties of flexible magnetic films by stress-related multi-fields, and the design and fabrication of flexible magnetic devices.
基金supported by China National 973 Project(No.2010CB933901)National 863 Hi-tech Project(Nos.2007AA022004 and 2005AA001070)National Natural Scientific Fund(No.30672147).
文摘Human Neurobeachin-like 1(NBEAL1)gene was an important member of BEACH-WD40 domain family,which was confirmed to be overexpressed in I stage glioma.In this study,we extracted total RNAs from U251 cell line,acquired its cDNA sequence by RT-PCR,and cloned part of NBEAL1 cDNA fragments into the vector pGEX-KG.The recombinant expression vector achieved high expression in E.coli BL21 as a GST fusion protein.NBEAL1 recombinant protein was purified by affinity chromatography.Monoclonal antibody was prepared against the recombinant NBEAL1 protein.Its bioactivity was identified by Western Blotting analysis.Anti-NBEAL1 antibody was conjugated with CdTe quantum dots.Resultant anti-NBEAL1 antibody-conjugated nanoprobes were injected into mice via tail vessel.After 12h,it is clearly observed that prepared nanoprobes located in brain tissues of mice model with glioma by IVIS Imaging system.In conclusion,NBEAL1 protein was successfully expressed and its monoclonal antibody was successfully prepared.Anti-NBEAL1 antibody-conjugated quantum dots may be used to image glioma.These prepared nanoprobes have great potential in early detection of glioma.
基金financially supported by the Central government guides local science and technology development fund of China(20231zdf03076)the Package Pilot Demonstration Program of Jiangxi Academy of Sciences(2022YSBG21002)+2 种基金the Introduction of Doctoral Program of Jiangxi Academy of Sciences(2022YYB20)the Research Program of State Key Laboratory of Food Science and Technology,Nanchang University(SKLF-KF-201812 and SKLF-ZZB-201916)National Natural Science Foundation of China(32060516).
文摘There were no reports on the anti-inflammatory effect of the seed of C.camphora(CCS)and the changes in the process of processing and consumption.The aim of the study was to investigate the anti-inflammatory activity of CCS ethanol extracts(EE),and the changes of it after simulated gastrointestinal digestion and alkaline hydrolysis in a lipopolysaccharide(LPS)-induced inflammatory macrophages model in vitro.The phytochemical charac-teristics of EE,digested ethanol extracts(dEE)and hydrolysed ethanol extracts(hEE)were analyzed using UPLCLTQOrbitrap-MS/MS in this study,and 17 chemicals were tentatively identified from the three prepared sam-ples.EE,dEE and hEE may have cell protection function,and both of them exhibited strong anti-inflammatory activity as significantly reduced multiple pro-inflammatory mediators and cytokines secretion and expression.Although the anti-inflammatory activity of EE was decreased by digestion and hydrolysis,and hydrolysis had more negative effect than digestion,most of its anti-inflammatory activity was retained.The mitigation of inflammation of EE may be by suppressing phosphorylation levels of signaling molecules of nuclear factor kappa B(NF-κB)and mitogen-activated protein kinases(MAPKs)signaling pathways.The results suggest that the anti-inflammatory activity of EE is relatively stable undergo gastrointestinal digestion and alkaline hydrolysis,which may facilitate the processing and consumption of related products.
基金supported by the grants DAG03/04.SC21 and RGC-CERG 604803。
文摘The no-slip boundary condition,i.e.,zero fluid velocity relative to the solid at the fluid-solid interface,has been very successful in describing many macroscopic flows.A problem of principle arises when the no-slip boundary condition is used to model the hydrodynamics of immiscible-fluid displacement in the vicinity of the moving contact line,where the interface separating two immiscible fluids intersects the solid wall.Decades ago it was already known that the moving contact line is incompatible with the no-slip boundary condition,since the latter would imply infinite dissipation due to a non-integrable singularity in the stress near the contact line.In this paper we first present an introductory review of the problem.We then present a detailed review of our recent results on the contact-line motion in immiscible two-phase flow,from molecular dynamics(MD)simulations to continuum hydrodynamics calculations.Through extensive MD studies and detailed analysis,we have uncovered the slip boundary condition governing the moving contact line,denoted the generalized Navier boundary condition.We have used this discovery to formulate a continuum hydrodynamic model whose predictions are in remarkable quantitative agreement with the MD simulation results down to the molecular scale.These results serve to affirm the validity of the generalized Navier boundary condition,as well as to open up the possibility of continuum hydrodynamic calculations of immiscible flows that are physically meaningful at the molecular level.
