Objective:Verrucous epidermal nevus(VEN),seborrheic keratosis(SK),verruca plana(VP),verruca vulgaris(VV),and nevus sebaceous(NS)are common verrucous proliferative skin diseases with similar clinical appearances,often ...Objective:Verrucous epidermal nevus(VEN),seborrheic keratosis(SK),verruca plana(VP),verruca vulgaris(VV),and nevus sebaceous(NS)are common verrucous proliferative skin diseases with similar clinical appearances,often posing diagnostic challenges.Dermoscopy and reflectance confocal microscopy(RCM)can aid in their differentiation,yet their specific features under these tools have not been systematically described.This study aims to summarize and analyze the dermoscopic and RCM features of VEN,SK,VP,VV,and NS.Methods:A total of 121 patients with histopathologically confirmed verrucous proliferative skin diseases were enrolled.Dermoscopy and RCM imaging was used to observe and analyze the microscopic features of these conditions.Results:Under dermoscopy,the 5 diseases displayed distinct characteristics:VEN typically showed gyriform structures;SK was characterized by gyriform structures,comedo-like openings,and milia-like cysts;VP and VV featured dotted vessels and frogspawn-like structures;NS presented as brownish-yellow globules.RCM revealed shared features such as hyperkeratosis and acanthosis across all 5 diseases.Specific features included gyriform structures and elongated rete ridges in VEN;pseudocysts and gyriform structures in SK;evenly distributed ring-like structures in VP;vacuolated cells and papillomatous proliferation in VV;and frogspawn-like structures in NS.Conclusion:These 5 verrucous proliferative skin conditions exhibit distinguishable features under both dermoscopy and RCM.The combination of these 2 noninvasive imaging modalities holds significant clinical value for the differential diagnosis of verrucous proliferative skin diseases.展开更多
Two-photon fluorescence microscopy,based on the principles of two-photon excited fluorescence and second harmonic generation,enables real-time non-invasive in vivo imaging of skin and cells,providing a means to assess...Two-photon fluorescence microscopy,based on the principles of two-photon excited fluorescence and second harmonic generation,enables real-time non-invasive in vivo imaging of skin and cells,providing a means to assess human health status.In this paper,a miniaturized two-photon imaging system is designed and fabricated to withstand extreme vibration and shock environments.The mechanical stability of the optical and structural components of the miniaturized probe is evaluated under random vibration and shock vibration tests using finite element simulation methods and ray tracing techniques.During the environmental testing,the maximum stress on the probe is 11.5 MPa,which is well below the threshold for structural failure.The largest structural displacement occurs at the collimator,where random vibrations produce an offset of 10.9μm.This offset is analyzed by using geometric optics and point spread functions.Under the maximum collimator offset,the theoretical resolution,as calculated by the point spread function,shifted from 463.28 nm to 463.48 nm.Additionally,a lateral offset of 127 nm is observed at the center position,which does not significantly impact the imaging performance.Finally,environmental and imaging performance tests are conducted.The system’s measured resolution after the environmental tests is 530 nm,consistent with its resolution prior to testing.Imaging tests are also performed on the skin’s stratum corneum,granular layer,spinous layer,and basal cell layer,revealing clear cellular structural information.These results confirm the device’s potential for applications in extreme shock and vibration environments.展开更多
Introduction The endothelial cells(ECs)lining every blood vessel wall constantly expose to the mechanical forces generated by the blood flow.The EC responses to these hemodynamic forces play a critical role in the hom...Introduction The endothelial cells(ECs)lining every blood vessel wall constantly expose to the mechanical forces generated by the blood flow.The EC responses to these hemodynamic forces play a critical role in the homeostasis of the circulatory system.In addition to forming a transport barrier between the blood and vessel wall,vascular ECs play important roles in regulating circulation functions.Besides biochemical stimuli,blood flow induced(hemodynamic)mechanical stimuli,such as shear stress,pressure and circumferential stretch,modulate EC morphology and functions by activating mechanosensors,signaling pathways,and gene and protein expressions.The EC responses to the hemodynamic forces(mechano-sensing and transduction)are critical to maintaining normal vascular functions.Failure in the mechano-sensing and transduction leads to serious vascular diseases including hypertension,atherosclerosis,aneurysms and thrombosis,to name a few[1].On the luminal surface of our blood vessels,there is a thin layer called endothelial surface glycocalyx(ESG)which consists of proteoglycans,glycosaminoglycans(GAGs)and glycoproteins.The GAGs in the ESG are heparan sulfate(HS),hyaluronic acid(HA),chondroitin sulfate(CS),and sialic acid(SA)[2].In order to play important roles in vascular functions,such as being a mechanosensor and transducer for the endothelial cells(ECs)to sense the blood flow,a molecular sieve to maintain normal microvessel permeability and a barrier between the circulating cells and endothelial cells forming the vessel wall,the ESG should have an organized structure at the molecular level.Due to the limitations of optical and electron microscopy,the ultra-structure and organization of ESG has not been revealed until recent development of a super high resolution fluorescence optical microscope,STORM(Stochastic Optical Reconstruction Microscopy).The diffraction of a single fluorescence molecule can be described as the point spread function(PSF).When the light of wavelengthλexcites the fluorophore(emitter),the intensity profile of the spot is defined as the PSF with the width^0.6λ/NA,NA is the numerical aperture of the objective.The diffraction-limited image resolution,for a high numerical aperture objective lens,is^200 nm in the lateral direction and^500 nm in the axial direction,for a conventional fluorescence microscope.The key idea of the single-molecule localization microscopy is to light the molecule,in turn,to achieve the nanometer-level accuracy of their position and reconstruction into a super-resolution image,such as STORM.STORM employs photo-switching mechanisms to stochastically activate individual molecules(photo-switchable or photoactivatable fluorophores)within the diffraction-limited region at different times.Then images with sub-diffraction limit resolution are reconstructed from the measured positions of individual fluorophores[3].To trade the super spatial resolution(accuracy),STORM sacrifices its temporal resolution(efficiency)by switching the state and sequentially exciting the emitters at a high density.Rust et al[3]employed organic dyes and fluorescent proteins as photo-switchable emitters to trade temporal resolution for a super spatial resolution(~20 nm lateral and^50 nm axial at present,can go down to a couple of nanometers if using smaller peptides or antibody fragments instead of currently used whole anti-bodies),which is an order of magnitude higher than conventional confocal microscopy.In the current study,we employed STORM to reveal the major ultra-structural components of the ESG,HS and HA,and their organization at the surface of the cultured EC monolayer[4].Materials and methods We used newly acquired Nikon-STORM system to observe the ESG on in vitro EC(bEnd3,mouse brain microvascular endothelial cells)monolayers.After confluency,the bEnd3 cells were immunolabeled with anti-HS,fol-lowed by an ATT0488 conjugated goat anti-mouse IgG,and with biotinylated HA binding protein,followed by an AF647 conjugated anti-biotin.The ESG was then imaged by the STORM with a 100x/1.49 oil immersed lens.Multiple Reporters of ATT0488 and AF647 with alternating illumination were used to acquire the 3D images of HS and HA.The field of 256×256(40×40μm2)of HS and HA at the surface of ECs was obtained based on totally 40,000 of EM-CCD captured images for each reporter at a capturing speed of 19 ms/frame.Results HA is a long molecule weaving into a network which covers the endothelial luminal surface.The diameter of the HA segments is 185.3±44.7 nm,155.5±57.2 nm,and 156.9±56.1 nm,respectively,at the top,middle and bottom regions of the cell luminal surface.In contrast,HS is a shorter molecule,perpendicular to the cell surface.HA and HS are partially overlapped with each other at the endothelial luminal surface.We quantified the length,diameter,orientation,and density of HS at the top,middle and bottom regions of the endothelial surface.The diameter of the observed HS is 191.0±46.0 nm,284.3±71.1 nm,and 184.2±59.6 nm,and the length of the HS is 621.0±75.7 nm,651.0±118.0 nm,and 575.2±105.6 nm,respectively,at the top,middle and bottom regions of the cell luminal surface.For the HS orientation,its angle with the cell surface is 92.9±1.9,88.7±8.2,and 96.2±10.9 degree,respectively,at the top,middle and bottom regions.The angle of 90 degree is perfectly perpendicular to the cell surface.For the HS distribution,the average density is0.398 elements/μm2,0.345 elements/μm2 and 0.665 elements/μm2,respectively,and the distance between the adjacent HS is 1 694.4±628.1 nm,1 844.8±758.5 nm,and 1 221.9±450.7 nm,respectively,at the top,middle and bottom regions.Conclusions Our results suggest that HS plays a major role in mechanosensing and HA plays a major role in the molecular sieve,due to their organization,ultra-structure and distribution.展开更多
Non-contact atomic force microscope(NC-AFM)has become a powerful tool.It can provide the atomic structure and chemical bonding information at the atomic scale.Three kinds of tip-sample interactions are often concerned...Non-contact atomic force microscope(NC-AFM)has become a powerful tool.It can provide the atomic structure and chemical bonding information at the atomic scale.Three kinds of tip-sample interactions are often concerned:including van der Waals interaction,electrostatic interaction,and chemical bonding interaction.In this work,the chemical bonding interaction between the tip and a Pb film is clearly demonstrated by NC-AFM based on a Q-plus force sensor.The tip-sample interaction energy versus the bias voltage was obtained and fitted by a parabolic function to find the effective local contact potential difference,which decreased with increasing tip-sample distance.Such a trend is caused by the wave function overlap.Thus,the decay length of the electron wave function was estimated.Oscillation of the decay length with film thickness was also observed,which can be attributed to the thickness-dependent quantum well states in the Pb islands.展开更多
Conventional electron and optical microscopy techniques require the sample to be sectioned, polished or etched to expose the internal surfaces for imaging. However, such sample preparation techniques have traditionall...Conventional electron and optical microscopy techniques require the sample to be sectioned, polished or etched to expose the internal surfaces for imaging. However, such sample preparation techniques have traditionally prevented the observation of the same sample over time, under realistic three-dimensional geometries and in an environment representative of real-world operating conditions. X-ray microscopy (XRM) is a rapidly emerging technique that enables non-destructive evaluation of buried structures within hard to soft materials in 3D, requiring little to no sample preparation. Furthermore in situ and 4D quantification of microstructural evolution under controlled environment as a function of time, temperature, chemistry or stress can be done repeatable on the same sample, using practical specimen sizes ranging from tens of microns to several cm diameter, with achievable imaging resolution from submicron to 50 nm. Many of these studies were reported using XRM in synchrotron beamlines. These include crack propagation on composite and construction materials; corrosion studies; microstructural changes during the setting of cement; flow studies within porous media to mention but a few.展开更多
Hefei Light Source(HLS)is a synchrotron radiation light source that primarily produces vacuum ultraviolet and soft X-rays.It currently consists of ten experimental stations,including a soft X-ray microscopy station.As...Hefei Light Source(HLS)is a synchrotron radiation light source that primarily produces vacuum ultraviolet and soft X-rays.It currently consists of ten experimental stations,including a soft X-ray microscopy station.As part of its on-going efforts to establish a centralized scientific data management platform,HLS is in the process of developing a test sys-tem that covers the entire lifecycle of scientific data,including data generation,acquisition,processing,analysis,and de-struction.However,the instruments used in the soft X-ray microscopy experimental station rely on commercial propriet-ary software for data acquisition and processing.We developed a semi-automatic data acquisition program to facilitate the integration of soft X-ray microscopy stations into a centralized scientific data management platform.Additionally,we cre-ated an online data processing platform to assist users in analyzing their scientific data.The system we developed and de-ployed meets the design requirements,successfully integrating the soft X-ray microscopy station into the full lifecycle management of scientific data.展开更多
Flagellated bacteria exhibit significantly altered motility near solid-liquid interfaces,affecting key biological processes such as biofilm formation and pathogenic infection.In this study,we present a simplified in-l...Flagellated bacteria exhibit significantly altered motility near solid-liquid interfaces,affecting key biological processes such as biofilm formation and pathogenic infection.In this study,we present a simplified in-line digital holographic microscopy(DHM)system tailored for high-throughput,label-free imaging of Escherichia coli(E.coli)swimming in near-surface environments.By applying a sliding median filter and mean normalization,we effectively suppress speckle noise and background artifacts in holograms.We introduce a morphology-aware workflow combining a voting algorithm,fast Fourier transform(FFT)analysis,and Bayesian optimization to robustly estimate bacterial positions and orientations,overcoming instability challenges common in non-spherical scattering models.Additionally,we employ a discrete dipole approximation(DDA)with a Levenberg-Marquardt(LM)optimizer to simulate and fit holographic interference patterns,achieving submicron axial precision and accurate tilt and azimuth angle measurements near surfaces.Through experiments tracking E.coli near surfaces,we quantitatively characterize swimming speed,trajectory geometry,and cell body orientation with high temporal resolution,revealing critical features of near-surface bacterial motility.Our results demonstrate the feasibility of single-beam DHM for rapid,quantitative tracking of bacterial surface behavior,providing an accessible and powerful tool for investigating microbe—interface interactions in biophysical and biomedical research.展开更多
钠超离子导体(natrium super ionic conductor,NASICON)型Na_(3)V_(2)(PO_(4))_(3)作为一种备受关注的钠离子电池正极材料,探究离子掺杂改性对其微观结构以及充放电过程中循环稳定性的影响具有至关重要的意义。本文利用透射电子显微技...钠超离子导体(natrium super ionic conductor,NASICON)型Na_(3)V_(2)(PO_(4))_(3)作为一种备受关注的钠离子电池正极材料,探究离子掺杂改性对其微观结构以及充放电过程中循环稳定性的影响具有至关重要的意义。本文利用透射电子显微技术与电化学测试方法,研究了Cu^(2+)掺杂对Na_(3)V_(2)(PO_(4))_(3)微观结构及其充放电过程中循环稳定性的影响。实验结果表明,Cu^(2+)掺杂会引起Na_(3)V_(2)(PO_(4))_(3)晶格的轻微收缩,并使其在多次充放电循环中表现出更为优异的结构稳定性,从而提升了材料的电化学性能。研究结果加深了离子掺杂改性对钠离子电池正极材料微观结构调控及循环稳定性增强机制方面的理解,为高性能钠离子电池的复杂结构设计与优化提供参考。展开更多
Interplay between topology and magnetism can give rise to exotic properties in topological materials.Two-dimensional bismuth has been extensively studied owing to its topological states with a strong spin-orbit coupli...Interplay between topology and magnetism can give rise to exotic properties in topological materials.Two-dimensional bismuth has been extensively studied owing to its topological states with a strong spin-orbit coupling,and 1T-VTe_(2)monolayer theoretically predicted to host an intrinsic magnetism as experimentally suggested.In this work,we successfully constructed a vertical heterostructure composed of the two-dimensional Bi(110)monolayer and 1T-VTe_(2)monolayer by using molecular beam epitaxy(MBE).Scanning tunneling microscopy(STM)measurements revealed that the growth of Bi preferably occurs along the step edges of the VTe_(2)monolayer,forming a Bi(110)monolayer on top of the VTe_(2)monolayer next to a peripheral Bi bilayer.The Bi(100)/VTe_(2)heterostructure exhibits a specific lattice registry with a well-defined moiréperiodicity.Scanning tunneling spectroscopy(STS)measurements further unveiled an universal suppression in the local density-of-states at the boundary of the Bi(110)/VTe_(2)bilayer.By examining the atomic structures of Bi(110)boundaries,we found this effect does not originate from the previously proposed atomic reconstruction at the step edge of Bi(110),but is likely related to the magnetic properties of the VTe_(2)monolayer.展开更多
Enamel demineralization often occurs in the early stage of dental caries.Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries.Terahertz(THz)technolo⁃gy,especial...Enamel demineralization often occurs in the early stage of dental caries.Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries.Terahertz(THz)technolo⁃gy,especially continuous wave(CW)THz near-field scanning microscopy(THz-SNOM)with its nanoscale reso⁃lution,can be promising in biomedical imaging.In addition,compared with traditional THz time-domain spec⁃troscopy(TDS),portable solid-state source as the emission has higher power and SNR,lower cost,and can ob⁃tain more precise imaging.In this study,we employ CW THz-SNOM to further break the resolution limitations of conventional THz imaging techniques and successfully achieve the near-field imaging of demineralized enamel at the nanoscale.We keenly observe that the near-field signal of the enamel significantly lowers as demineralization deepens,mainly due to the decrease in permittivity.This new approach offers valuable insights into the micro⁃scopic processes of enamel demineralization,laying the foundation for further research and treatment.展开更多
This work presents a method for the three-dimensional localization of individual shallow NV center in diamond,leveraging the near-field quenching effect of a gold tip.Our experimental setup involves the use of an atom...This work presents a method for the three-dimensional localization of individual shallow NV center in diamond,leveraging the near-field quenching effect of a gold tip.Our experimental setup involves the use of an atomic force microscope to precisely move the gold tip close to the NV center,while simultaneously employing a home-made confocal microscope to monitor the fluorescence of the NV center.This approach allows for lateral super-resolution,achieving a full width at half maximum(FWHM)of 38.0 nm and a location uncertainty of 0.7 nm.Additionally,we show the potential of this method for determining the depth of the NV centers.We also attempt to determine the depth of the NV centers in combination with finite-difference time-domain(FDTD)simulations.Compared to other depth determination methods,this approach allows for simultaneous lateral and longitudinal localization of individual NV centers,and holds promise for facilitating manipulation of the local environment surrounding the NV center.展开更多
Background Cotton(Gossypium spp.) is an important commercial crop being cultivated worldwide, but its production is hampered by many insect pests. The cotton aphid, Aphis gossypii Glover, is a key pest with increasing...Background Cotton(Gossypium spp.) is an important commercial crop being cultivated worldwide, but its production is hampered by many insect pests. The cotton aphid, Aphis gossypii Glover, is a key pest with increasing resistance to chemical insecticides. To explore eco-friendly management alternatives, this study evaluates the pathogenic potential of indigenous entomopathogenic fungi, isolated from cotton-growing regions of Tamil Nadu, India, via the ‘Galleria bait method'.Results Five entomopathogenic fungi were isolated and identified as Beauveria spp. based on cultural and morphological features. Molecular characterization by amplification of internal transcribed spacer-ribosomal DNA(ITS-rDNA) regions confirmed the isolates as B. bassiana. Among them, isolate B5(accession number: PP503009) exhibited the highest virulence, inducing 96.67% mortality at 7 days after treatment(DAT) with the concentration of 1 × 10^(8) spores·mL^(-1). The median lethal concentration(LC_(50)) and median lethal time(LT_(50)) values were 9.75 × 10^(4) spores·mL^(-1) at 7 DAT and 72.31 h at 1 × 10^(8) spores·mL^(-1), respectively. Scanning electron microscopy(SEM) images highlighted a progression of infection stages of B5, including spore attachment(24 h post infection(hpi)), hyphal penetration(48 hpi), and conidiogenesis(72 hpi).Conclusion The isolate B5 proved to be a promising candidate for the development of biopesticides for sustainable cotton aphid management in Tamil Nadu, India.展开更多
Results of a hot stage polarization microscopy study on the first order phase-transitions in n-hexatriacontane hydrocarbon are presented.The main points discussed are(i)the intermediatary phase to monoclinic-->orth...Results of a hot stage polarization microscopy study on the first order phase-transitions in n-hexatriacontane hydrocarbon are presented.The main points discussed are(i)the intermediatary phase to monoclinic-->orthorhombic tran-sition and(ii)the transition boundary layer.展开更多
Chrome steels are used in bearings since they possess high strength and wear resistance.However,when those parts are in service,failure happens due to sliding friction before the lifetime.To improve the durability of ...Chrome steels are used in bearings since they possess high strength and wear resistance.However,when those parts are in service,failure happens due to sliding friction before the lifetime.To improve the durability of the American Iron and Steel Institute(AISI)52100 chromium steel,in this work,the effect of laser surface texturing(LST)was analyzed.With the different patterns of circle and ellipse comparing with the untextured samples,the wear behavior was investigated using the pin-on-disc tribometer.The lubricant used for wear analysis is semisolid lithium grease National Lubricating Grease Institute lubricant(SKF NLGI-3).Sliding wear analysis was conducted at different loads of 10 N,30 N and 50 N for the sliding speed of 750 r/min and 1400 r/min.The wear morphology was analyzed using a scanning electron microscope(SEM).The roughness of the samples was found using a white light interferometer.The effect of different patterns like circle and ellipse,alter the friction and wear properties of chromium alloy was observed compared with the untextured samples.LST shows considerable reduction in friction and wear for ellipsoidal pattern compared with the circular pattern because of wear debris and lubricant getting trapped.展开更多
Metal single atom catalysts(SACs)have been attracting increasing attention in recent years owing to their incredibleperformance in several key catalytic reactions such as the oxygen reduction reaction and CO oxidation...Metal single atom catalysts(SACs)have been attracting increasing attention in recent years owing to their incredibleperformance in several key catalytic reactions such as the oxygen reduction reaction and CO oxidation.The construction of well dis-persed stable SACs can not only make it possible to understand the catalytic reactions on the atomic scale,but is also important for developing novel industrial catalysts.Recent efforts have been focused on dispersing metal SACs on carbon substrates rather than on metals or metal oxides for improved catalytic behavior.Especially,graphene-based materials have proven to be excellent candidates for supporting SACs due to their unique structural and electronic properties.Nevertheless,the anchoring mechanism between metal SACs and carbon substrates is not well understood.Here we review the many roles of carbon materials as the support of SACs and highlight the anchoring mechanism.We also propose some suggestions to improve the experimental and theoretical research methods to expand the number of applications and realize industrial applications.展开更多
To investigate the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites,uniaxial compression test,variable-angle shear test,acoustic emission signal monitoring and the ...To investigate the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites,uniaxial compression test,variable-angle shear test,acoustic emission signal monitoring and the measurement of physical parameters including mass,size and P-wave velocity were carried out on granite samples treated at temperatures T ranging from 25 to 900℃.The results show that the density and P-wave velocity decrease gradually with increasing T.As the temperature increases,the peak compressive stress decreases while the peak strain increases,due to the fact that a high temperature induces the escaping of waters within granites,the expanding of mineral grains and the generations of fractures.With the increment of T,both the peak shear stress and the cohesion decrease,whereas the frictional angle increases.During the compressing and shearing tests,the maximum acoustic emission counts show a decreasing trend when T increases from 25 to 900℃.When T exceeds 573℃,the crystal lattice structure of quartz changes fromα-phase toβ-phase,decreasing the mechanical behavior of granites to a great extent.In addition,the results also indicate that T=500−600℃ is the critical temperature ramge to characterize the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites.展开更多
Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature a...Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature and humidity cycling test,soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S)grout.Density,surface hardness,water penetration capacity,water permeability capacity,soluble salt,scanning electron microscopy(SEM)images and energy dispersive spectrometry(EDS)spectrum of these samples have been tested after accelerated ageing tests.The results show that densities of samples decrease,surface hardness,water penetration capacity and water permeability capacity of samples increase generally.Besides,soluble salt analysis,SEM and EDS results well corroborate the changes.Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test,followed by water stability,soundness and alkali resistance test in sequence.But in general,CGN-(F+S)still has good durability.展开更多
The durability of silty clay embankments is partially controlled by the moisture migration, which depends on soil hydraulic properties. This paper presents an experimental study of hydraulic properties of compacted bi...The durability of silty clay embankments is partially controlled by the moisture migration, which depends on soil hydraulic properties. This paper presents an experimental study of hydraulic properties of compacted binary silty clay. Specimens with different mixing ratios and dry densities were prepared. Scanning electron microscopy and mercury intrusion porosimetry were used to characterise the microstructure of silty clay. Thereafter, falling-head permeability tests and water retention tests were conducted to study the permeability and water retention property, respectively. The results demonstrate that clay particles are dispersed and show preferred arrangements after compaction when the clay content is 100%. As the clay content decreases, the arrangement of clay particles is gradually disturbed because of the existence of silt particles, causing the formation of large pores around silt particles. When the dry density increases, the pores around silt particles significantly decrease. Moreover, the permeability of silty clay decreases but the water retention capacity increases with increasing clay content and dry density. This is because the silty clay with larger clay content and dry density has fewer large pores, which greatly restrains the flow of water. Both the permeability and water retention property of silty clay can be predicted from pore size distribution parameters.展开更多
基金supported by the Project of Health Committee of Hunan Province(D202304128868),China.
文摘Objective:Verrucous epidermal nevus(VEN),seborrheic keratosis(SK),verruca plana(VP),verruca vulgaris(VV),and nevus sebaceous(NS)are common verrucous proliferative skin diseases with similar clinical appearances,often posing diagnostic challenges.Dermoscopy and reflectance confocal microscopy(RCM)can aid in their differentiation,yet their specific features under these tools have not been systematically described.This study aims to summarize and analyze the dermoscopic and RCM features of VEN,SK,VP,VV,and NS.Methods:A total of 121 patients with histopathologically confirmed verrucous proliferative skin diseases were enrolled.Dermoscopy and RCM imaging was used to observe and analyze the microscopic features of these conditions.Results:Under dermoscopy,the 5 diseases displayed distinct characteristics:VEN typically showed gyriform structures;SK was characterized by gyriform structures,comedo-like openings,and milia-like cysts;VP and VV featured dotted vessels and frogspawn-like structures;NS presented as brownish-yellow globules.RCM revealed shared features such as hyperkeratosis and acanthosis across all 5 diseases.Specific features included gyriform structures and elongated rete ridges in VEN;pseudocysts and gyriform structures in SK;evenly distributed ring-like structures in VP;vacuolated cells and papillomatous proliferation in VV;and frogspawn-like structures in NS.Conclusion:These 5 verrucous proliferative skin conditions exhibit distinguishable features under both dermoscopy and RCM.The combination of these 2 noninvasive imaging modalities holds significant clinical value for the differential diagnosis of verrucous proliferative skin diseases.
基金supported by the National Natural Science Foundation of China(62475008,62305186).
文摘Two-photon fluorescence microscopy,based on the principles of two-photon excited fluorescence and second harmonic generation,enables real-time non-invasive in vivo imaging of skin and cells,providing a means to assess human health status.In this paper,a miniaturized two-photon imaging system is designed and fabricated to withstand extreme vibration and shock environments.The mechanical stability of the optical and structural components of the miniaturized probe is evaluated under random vibration and shock vibration tests using finite element simulation methods and ray tracing techniques.During the environmental testing,the maximum stress on the probe is 11.5 MPa,which is well below the threshold for structural failure.The largest structural displacement occurs at the collimator,where random vibrations produce an offset of 10.9μm.This offset is analyzed by using geometric optics and point spread functions.Under the maximum collimator offset,the theoretical resolution,as calculated by the point spread function,shifted from 463.28 nm to 463.48 nm.Additionally,a lateral offset of 127 nm is observed at the center position,which does not significantly impact the imaging performance.Finally,environmental and imaging performance tests are conducted.The system’s measured resolution after the environmental tests is 530 nm,consistent with its resolution prior to testing.Imaging tests are also performed on the skin’s stratum corneum,granular layer,spinous layer,and basal cell layer,revealing clear cellular structural information.These results confirm the device’s potential for applications in extreme shock and vibration environments.
基金supported by NIH-1SC1CA153325-01,NSF-MRI CBET 1337746 and 1UG3TR002151-01
文摘Introduction The endothelial cells(ECs)lining every blood vessel wall constantly expose to the mechanical forces generated by the blood flow.The EC responses to these hemodynamic forces play a critical role in the homeostasis of the circulatory system.In addition to forming a transport barrier between the blood and vessel wall,vascular ECs play important roles in regulating circulation functions.Besides biochemical stimuli,blood flow induced(hemodynamic)mechanical stimuli,such as shear stress,pressure and circumferential stretch,modulate EC morphology and functions by activating mechanosensors,signaling pathways,and gene and protein expressions.The EC responses to the hemodynamic forces(mechano-sensing and transduction)are critical to maintaining normal vascular functions.Failure in the mechano-sensing and transduction leads to serious vascular diseases including hypertension,atherosclerosis,aneurysms and thrombosis,to name a few[1].On the luminal surface of our blood vessels,there is a thin layer called endothelial surface glycocalyx(ESG)which consists of proteoglycans,glycosaminoglycans(GAGs)and glycoproteins.The GAGs in the ESG are heparan sulfate(HS),hyaluronic acid(HA),chondroitin sulfate(CS),and sialic acid(SA)[2].In order to play important roles in vascular functions,such as being a mechanosensor and transducer for the endothelial cells(ECs)to sense the blood flow,a molecular sieve to maintain normal microvessel permeability and a barrier between the circulating cells and endothelial cells forming the vessel wall,the ESG should have an organized structure at the molecular level.Due to the limitations of optical and electron microscopy,the ultra-structure and organization of ESG has not been revealed until recent development of a super high resolution fluorescence optical microscope,STORM(Stochastic Optical Reconstruction Microscopy).The diffraction of a single fluorescence molecule can be described as the point spread function(PSF).When the light of wavelengthλexcites the fluorophore(emitter),the intensity profile of the spot is defined as the PSF with the width^0.6λ/NA,NA is the numerical aperture of the objective.The diffraction-limited image resolution,for a high numerical aperture objective lens,is^200 nm in the lateral direction and^500 nm in the axial direction,for a conventional fluorescence microscope.The key idea of the single-molecule localization microscopy is to light the molecule,in turn,to achieve the nanometer-level accuracy of their position and reconstruction into a super-resolution image,such as STORM.STORM employs photo-switching mechanisms to stochastically activate individual molecules(photo-switchable or photoactivatable fluorophores)within the diffraction-limited region at different times.Then images with sub-diffraction limit resolution are reconstructed from the measured positions of individual fluorophores[3].To trade the super spatial resolution(accuracy),STORM sacrifices its temporal resolution(efficiency)by switching the state and sequentially exciting the emitters at a high density.Rust et al[3]employed organic dyes and fluorescent proteins as photo-switchable emitters to trade temporal resolution for a super spatial resolution(~20 nm lateral and^50 nm axial at present,can go down to a couple of nanometers if using smaller peptides or antibody fragments instead of currently used whole anti-bodies),which is an order of magnitude higher than conventional confocal microscopy.In the current study,we employed STORM to reveal the major ultra-structural components of the ESG,HS and HA,and their organization at the surface of the cultured EC monolayer[4].Materials and methods We used newly acquired Nikon-STORM system to observe the ESG on in vitro EC(bEnd3,mouse brain microvascular endothelial cells)monolayers.After confluency,the bEnd3 cells were immunolabeled with anti-HS,fol-lowed by an ATT0488 conjugated goat anti-mouse IgG,and with biotinylated HA binding protein,followed by an AF647 conjugated anti-biotin.The ESG was then imaged by the STORM with a 100x/1.49 oil immersed lens.Multiple Reporters of ATT0488 and AF647 with alternating illumination were used to acquire the 3D images of HS and HA.The field of 256×256(40×40μm2)of HS and HA at the surface of ECs was obtained based on totally 40,000 of EM-CCD captured images for each reporter at a capturing speed of 19 ms/frame.Results HA is a long molecule weaving into a network which covers the endothelial luminal surface.The diameter of the HA segments is 185.3±44.7 nm,155.5±57.2 nm,and 156.9±56.1 nm,respectively,at the top,middle and bottom regions of the cell luminal surface.In contrast,HS is a shorter molecule,perpendicular to the cell surface.HA and HS are partially overlapped with each other at the endothelial luminal surface.We quantified the length,diameter,orientation,and density of HS at the top,middle and bottom regions of the endothelial surface.The diameter of the observed HS is 191.0±46.0 nm,284.3±71.1 nm,and 184.2±59.6 nm,and the length of the HS is 621.0±75.7 nm,651.0±118.0 nm,and 575.2±105.6 nm,respectively,at the top,middle and bottom regions of the cell luminal surface.For the HS orientation,its angle with the cell surface is 92.9±1.9,88.7±8.2,and 96.2±10.9 degree,respectively,at the top,middle and bottom regions.The angle of 90 degree is perfectly perpendicular to the cell surface.For the HS distribution,the average density is0.398 elements/μm2,0.345 elements/μm2 and 0.665 elements/μm2,respectively,and the distance between the adjacent HS is 1 694.4±628.1 nm,1 844.8±758.5 nm,and 1 221.9±450.7 nm,respectively,at the top,middle and bottom regions.Conclusions Our results suggest that HS plays a major role in mechanosensing and HA plays a major role in the molecular sieve,due to their organization,ultra-structure and distribution.
文摘Non-contact atomic force microscope(NC-AFM)has become a powerful tool.It can provide the atomic structure and chemical bonding information at the atomic scale.Three kinds of tip-sample interactions are often concerned:including van der Waals interaction,electrostatic interaction,and chemical bonding interaction.In this work,the chemical bonding interaction between the tip and a Pb film is clearly demonstrated by NC-AFM based on a Q-plus force sensor.The tip-sample interaction energy versus the bias voltage was obtained and fitted by a parabolic function to find the effective local contact potential difference,which decreased with increasing tip-sample distance.Such a trend is caused by the wave function overlap.Thus,the decay length of the electron wave function was estimated.Oscillation of the decay length with film thickness was also observed,which can be attributed to the thickness-dependent quantum well states in the Pb islands.
文摘Conventional electron and optical microscopy techniques require the sample to be sectioned, polished or etched to expose the internal surfaces for imaging. However, such sample preparation techniques have traditionally prevented the observation of the same sample over time, under realistic three-dimensional geometries and in an environment representative of real-world operating conditions. X-ray microscopy (XRM) is a rapidly emerging technique that enables non-destructive evaluation of buried structures within hard to soft materials in 3D, requiring little to no sample preparation. Furthermore in situ and 4D quantification of microstructural evolution under controlled environment as a function of time, temperature, chemistry or stress can be done repeatable on the same sample, using practical specimen sizes ranging from tens of microns to several cm diameter, with achievable imaging resolution from submicron to 50 nm. Many of these studies were reported using XRM in synchrotron beamlines. These include crack propagation on composite and construction materials; corrosion studies; microstructural changes during the setting of cement; flow studies within porous media to mention but a few.
基金supported by the Fundamental Research Funds for the Central Universities(WK2310000102)。
文摘Hefei Light Source(HLS)is a synchrotron radiation light source that primarily produces vacuum ultraviolet and soft X-rays.It currently consists of ten experimental stations,including a soft X-ray microscopy station.As part of its on-going efforts to establish a centralized scientific data management platform,HLS is in the process of developing a test sys-tem that covers the entire lifecycle of scientific data,including data generation,acquisition,processing,analysis,and de-struction.However,the instruments used in the soft X-ray microscopy experimental station rely on commercial propriet-ary software for data acquisition and processing.We developed a semi-automatic data acquisition program to facilitate the integration of soft X-ray microscopy stations into a centralized scientific data management platform.Additionally,we cre-ated an online data processing platform to assist users in analyzing their scientific data.The system we developed and de-ployed meets the design requirements,successfully integrating the soft X-ray microscopy station into the full lifecycle management of scientific data.
基金supported by the National Natural Science Foundation of China(11904352).
文摘Flagellated bacteria exhibit significantly altered motility near solid-liquid interfaces,affecting key biological processes such as biofilm formation and pathogenic infection.In this study,we present a simplified in-line digital holographic microscopy(DHM)system tailored for high-throughput,label-free imaging of Escherichia coli(E.coli)swimming in near-surface environments.By applying a sliding median filter and mean normalization,we effectively suppress speckle noise and background artifacts in holograms.We introduce a morphology-aware workflow combining a voting algorithm,fast Fourier transform(FFT)analysis,and Bayesian optimization to robustly estimate bacterial positions and orientations,overcoming instability challenges common in non-spherical scattering models.Additionally,we employ a discrete dipole approximation(DDA)with a Levenberg-Marquardt(LM)optimizer to simulate and fit holographic interference patterns,achieving submicron axial precision and accurate tilt and azimuth angle measurements near surfaces.Through experiments tracking E.coli near surfaces,we quantitatively characterize swimming speed,trajectory geometry,and cell body orientation with high temporal resolution,revealing critical features of near-surface bacterial motility.Our results demonstrate the feasibility of single-beam DHM for rapid,quantitative tracking of bacterial surface behavior,providing an accessible and powerful tool for investigating microbe—interface interactions in biophysical and biomedical research.
文摘钠超离子导体(natrium super ionic conductor,NASICON)型Na_(3)V_(2)(PO_(4))_(3)作为一种备受关注的钠离子电池正极材料,探究离子掺杂改性对其微观结构以及充放电过程中循环稳定性的影响具有至关重要的意义。本文利用透射电子显微技术与电化学测试方法,研究了Cu^(2+)掺杂对Na_(3)V_(2)(PO_(4))_(3)微观结构及其充放电过程中循环稳定性的影响。实验结果表明,Cu^(2+)掺杂会引起Na_(3)V_(2)(PO_(4))_(3)晶格的轻微收缩,并使其在多次充放电循环中表现出更为优异的结构稳定性,从而提升了材料的电化学性能。研究结果加深了离子掺杂改性对钠离子电池正极材料微观结构调控及循环稳定性增强机制方面的理解,为高性能钠离子电池的复杂结构设计与优化提供参考。
基金financially supported by the National Key Research and Development Program of China(Grant No.2021YFA1400403)the National Natural Science Foundation of China(Grant Nos.12374183,92165205)+2 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20233001)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302800)the Fundamental Research Funds for the Central Universities(Grant No.020414380207).
文摘Interplay between topology and magnetism can give rise to exotic properties in topological materials.Two-dimensional bismuth has been extensively studied owing to its topological states with a strong spin-orbit coupling,and 1T-VTe_(2)monolayer theoretically predicted to host an intrinsic magnetism as experimentally suggested.In this work,we successfully constructed a vertical heterostructure composed of the two-dimensional Bi(110)monolayer and 1T-VTe_(2)monolayer by using molecular beam epitaxy(MBE).Scanning tunneling microscopy(STM)measurements revealed that the growth of Bi preferably occurs along the step edges of the VTe_(2)monolayer,forming a Bi(110)monolayer on top of the VTe_(2)monolayer next to a peripheral Bi bilayer.The Bi(100)/VTe_(2)heterostructure exhibits a specific lattice registry with a well-defined moiréperiodicity.Scanning tunneling spectroscopy(STS)measurements further unveiled an universal suppression in the local density-of-states at the boundary of the Bi(110)/VTe_(2)bilayer.By examining the atomic structures of Bi(110)boundaries,we found this effect does not originate from the previously proposed atomic reconstruction at the step edge of Bi(110),but is likely related to the magnetic properties of the VTe_(2)monolayer.
基金Supported by the National Natural Science Foundation of China(61988102,62401113,92463308)。
文摘Enamel demineralization often occurs in the early stage of dental caries.Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries.Terahertz(THz)technolo⁃gy,especially continuous wave(CW)THz near-field scanning microscopy(THz-SNOM)with its nanoscale reso⁃lution,can be promising in biomedical imaging.In addition,compared with traditional THz time-domain spec⁃troscopy(TDS),portable solid-state source as the emission has higher power and SNR,lower cost,and can ob⁃tain more precise imaging.In this study,we employ CW THz-SNOM to further break the resolution limitations of conventional THz imaging techniques and successfully achieve the near-field imaging of demineralized enamel at the nanoscale.We keenly observe that the near-field signal of the enamel significantly lowers as demineralization deepens,mainly due to the decrease in permittivity.This new approach offers valuable insights into the micro⁃scopic processes of enamel demineralization,laying the foundation for further research and treatment.
基金supported by the National Natural Science Foundation of China(T2325023,92265204,12104447)the National Key R&D Program of China(2023YFF0718400)+1 种基金the Innovation Program for Quantum Science and Technology(2021ZD0302200)the Fundamental Research Funds for the Central Universities。
文摘This work presents a method for the three-dimensional localization of individual shallow NV center in diamond,leveraging the near-field quenching effect of a gold tip.Our experimental setup involves the use of an atomic force microscope to precisely move the gold tip close to the NV center,while simultaneously employing a home-made confocal microscope to monitor the fluorescence of the NV center.This approach allows for lateral super-resolution,achieving a full width at half maximum(FWHM)of 38.0 nm and a location uncertainty of 0.7 nm.Additionally,we show the potential of this method for determining the depth of the NV centers.We also attempt to determine the depth of the NV centers in combination with finite-difference time-domain(FDTD)simulations.Compared to other depth determination methods,this approach allows for simultaneous lateral and longitudinal localization of individual NV centers,and holds promise for facilitating manipulation of the local environment surrounding the NV center.
文摘Background Cotton(Gossypium spp.) is an important commercial crop being cultivated worldwide, but its production is hampered by many insect pests. The cotton aphid, Aphis gossypii Glover, is a key pest with increasing resistance to chemical insecticides. To explore eco-friendly management alternatives, this study evaluates the pathogenic potential of indigenous entomopathogenic fungi, isolated from cotton-growing regions of Tamil Nadu, India, via the ‘Galleria bait method'.Results Five entomopathogenic fungi were isolated and identified as Beauveria spp. based on cultural and morphological features. Molecular characterization by amplification of internal transcribed spacer-ribosomal DNA(ITS-rDNA) regions confirmed the isolates as B. bassiana. Among them, isolate B5(accession number: PP503009) exhibited the highest virulence, inducing 96.67% mortality at 7 days after treatment(DAT) with the concentration of 1 × 10^(8) spores·mL^(-1). The median lethal concentration(LC_(50)) and median lethal time(LT_(50)) values were 9.75 × 10^(4) spores·mL^(-1) at 7 DAT and 72.31 h at 1 × 10^(8) spores·mL^(-1), respectively. Scanning electron microscopy(SEM) images highlighted a progression of infection stages of B5, including spore attachment(24 h post infection(hpi)), hyphal penetration(48 hpi), and conidiogenesis(72 hpi).Conclusion The isolate B5 proved to be a promising candidate for the development of biopesticides for sustainable cotton aphid management in Tamil Nadu, India.
文摘Results of a hot stage polarization microscopy study on the first order phase-transitions in n-hexatriacontane hydrocarbon are presented.The main points discussed are(i)the intermediatary phase to monoclinic-->orthorhombic tran-sition and(ii)the transition boundary layer.
文摘Chrome steels are used in bearings since they possess high strength and wear resistance.However,when those parts are in service,failure happens due to sliding friction before the lifetime.To improve the durability of the American Iron and Steel Institute(AISI)52100 chromium steel,in this work,the effect of laser surface texturing(LST)was analyzed.With the different patterns of circle and ellipse comparing with the untextured samples,the wear behavior was investigated using the pin-on-disc tribometer.The lubricant used for wear analysis is semisolid lithium grease National Lubricating Grease Institute lubricant(SKF NLGI-3).Sliding wear analysis was conducted at different loads of 10 N,30 N and 50 N for the sliding speed of 750 r/min and 1400 r/min.The wear morphology was analyzed using a scanning electron microscope(SEM).The roughness of the samples was found using a white light interferometer.The effect of different patterns like circle and ellipse,alter the friction and wear properties of chromium alloy was observed compared with the untextured samples.LST shows considerable reduction in friction and wear for ellipsoidal pattern compared with the circular pattern because of wear debris and lubricant getting trapped.
文摘Metal single atom catalysts(SACs)have been attracting increasing attention in recent years owing to their incredibleperformance in several key catalytic reactions such as the oxygen reduction reaction and CO oxidation.The construction of well dis-persed stable SACs can not only make it possible to understand the catalytic reactions on the atomic scale,but is also important for developing novel industrial catalysts.Recent efforts have been focused on dispersing metal SACs on carbon substrates rather than on metals or metal oxides for improved catalytic behavior.Especially,graphene-based materials have proven to be excellent candidates for supporting SACs due to their unique structural and electronic properties.Nevertheless,the anchoring mechanism between metal SACs and carbon substrates is not well understood.Here we review the many roles of carbon materials as the support of SACs and highlight the anchoring mechanism.We also propose some suggestions to improve the experimental and theoretical research methods to expand the number of applications and realize industrial applications.
基金Projects(51979272,BZ2020066)supported by the National Natural Science Foundation of ChinaProjet supported by the Department of Science and Technology of Jiangsu Province,China。
文摘To investigate the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites,uniaxial compression test,variable-angle shear test,acoustic emission signal monitoring and the measurement of physical parameters including mass,size and P-wave velocity were carried out on granite samples treated at temperatures T ranging from 25 to 900℃.The results show that the density and P-wave velocity decrease gradually with increasing T.As the temperature increases,the peak compressive stress decreases while the peak strain increases,due to the fact that a high temperature induces the escaping of waters within granites,the expanding of mineral grains and the generations of fractures.With the increment of T,both the peak shear stress and the cohesion decrease,whereas the frictional angle increases.During the compressing and shearing tests,the maximum acoustic emission counts show a decreasing trend when T increases from 25 to 900℃.When T exceeds 573℃,the crystal lattice structure of quartz changes fromα-phase toβ-phase,decreasing the mechanical behavior of granites to a great extent.In addition,the results also indicate that T=500−600℃ is the critical temperature ramge to characterize the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites.
基金Project(51578272)supported by the National Natural Science Foundation of China
文摘Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature and humidity cycling test,soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S)grout.Density,surface hardness,water penetration capacity,water permeability capacity,soluble salt,scanning electron microscopy(SEM)images and energy dispersive spectrometry(EDS)spectrum of these samples have been tested after accelerated ageing tests.The results show that densities of samples decrease,surface hardness,water penetration capacity and water permeability capacity of samples increase generally.Besides,soluble salt analysis,SEM and EDS results well corroborate the changes.Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test,followed by water stability,soundness and alkali resistance test in sequence.But in general,CGN-(F+S)still has good durability.
基金Projects(51908069, 51908073, 51838001, 51878070) supported by the National Natural Science Foundation of ChinaProject(2019SK2171) supported by the Key Research and Development Program of Hunan Province, China+2 种基金Project(kfj190605) supported by the Open Fund of Engineering Laboratory of Spatial Information Technology of Highway Geological Disaster Early Warning in Hunan Province (Changsha University of Science & Technology),ChinaProject(2019IC04) supported by the Double First-Class Scientific Research International Cooperation Expansion Project of Changsha University of Science & Technology, ChinaProject(kq1905043) supported by the Training Program for Excellent Young Innovators of Changsha, China。
文摘The durability of silty clay embankments is partially controlled by the moisture migration, which depends on soil hydraulic properties. This paper presents an experimental study of hydraulic properties of compacted binary silty clay. Specimens with different mixing ratios and dry densities were prepared. Scanning electron microscopy and mercury intrusion porosimetry were used to characterise the microstructure of silty clay. Thereafter, falling-head permeability tests and water retention tests were conducted to study the permeability and water retention property, respectively. The results demonstrate that clay particles are dispersed and show preferred arrangements after compaction when the clay content is 100%. As the clay content decreases, the arrangement of clay particles is gradually disturbed because of the existence of silt particles, causing the formation of large pores around silt particles. When the dry density increases, the pores around silt particles significantly decrease. Moreover, the permeability of silty clay decreases but the water retention capacity increases with increasing clay content and dry density. This is because the silty clay with larger clay content and dry density has fewer large pores, which greatly restrains the flow of water. Both the permeability and water retention property of silty clay can be predicted from pore size distribution parameters.
