Investigation intracellular trafficking of siRNAs following their delivery to cells is of great interest to elucidate dynamics of siRNA in cytoplasm. In this study, we present a novel confocal laser scanning microsco...Investigation intracellular trafficking of siRNAs following their delivery to cells is of great interest to elucidate dynamics of siRNA in cytoplasm. In this study, we present a novel confocal laser scanning microscopy （CLSM） method to evaluate a novel delivery system of 3＇-peptide-siRNA therapeutic, which was named 3＇-pAs-siRNA/CLD. This method could not only calculate the content of the intracellular 3＇-peptide-siRNA, but also quantify its co-localization with cellular substructure. We observed that 3＇-pAs-siRNA/CLD, which provided the better antitumor capability, also had a better cell uptake, endosome escape and a longer retention time in A375. This novel strategy was proved to be efficient, quantified and visualized, thus making the dynamics research of siRNA in cytoplasm clear and simplified.展开更多
Image scanning microscopy(ISM)is a promising imaging technique that offers sub-diffraction-limited resolution and optical sectioning.Theoretically,ISM can improve the optical resolution by a factor of two through pixe...Image scanning microscopy(ISM)is a promising imaging technique that offers sub-diffraction-limited resolution and optical sectioning.Theoretically,ISM can improve the optical resolution by a factor of two through pixel reassignment and deconvolution.Multifocal array illumination and scanning have been widely adopted to implement ISM because of their simplicity.Conventionally,digital micromirror devices(DMDs)1 and microlens arrays(MLAs)2,3 have been used to generate dense and uniform multifocal arrays for ISM,which are critical for achieving fast imaging and high-quality ISM reconstruction.However,these approaches have limitations in terms of cost,numerical aperture(NA),pitch,and uniformity,making it challenging to create dense and high-quality multifocal arrays at high NA.To overcome these limitations,we introduced a novel multifocal metalens design strategy called the hybrid multiplexing method,which combines two conventional multiplexing approaches:phase addition and random multiplexing.Through numerical simulations,we demonstrate that the proposed method generates more uniform and denser multifocal arrays than conventional methods,even at small pitches.As a proof of concept,we fabricated a multifocal metalens generating 40×40 array of foci with a 3μm pitch and NA of 0.7 operating at a wavelength of 488 nm and then constructed the multifocal metalens-based ISM(MMISM).We demonstrated that MMISM successfully resolved sub-diffraction-limited features in imaging of microbead samples and forebrain organoid sections.The results showed that MMISM imaging achieved twice the diffraction-limited resolution and revealed clearer structural features of neurons compared to wide-field images.We anticipate that our novel design strategy can be widely applied to produce multifunctional optical elements and replace conventional optical elements in specialized applications.展开更多
Detecting microplastics(MPs)under 20μm has been challenging,yet these tiny particles may pose significant threats to human health and the environment.They can be inhaled or ingested,potentially leading to respiratory...Detecting microplastics(MPs)under 20μm has been challenging,yet these tiny particles may pose significant threats to human health and the environment.They can be inhaled or ingested,potentially leading to respiratory diseases and gastrointestinal problems.This research proposed confocal laser scanning microscopy(CLSM)for identifying MPs smaller than 20μm and to support its validity by comparing results to a typical gravimetric analysis for these small MPs in road dust samples using pyrolysis-gas chromatography/mass spectrometry(Pyr-GC/MS).A total of 30 road dust samples were collected from urban areas in Seoul and 15 samples from rural regions throughout South Korea.A strong agreement was observed between the results obtained from CLSM and Pyr-GC/MS,confirming the effectiveness of both methods in measuring MPs under 20μm especially when polyolefins are dominating MPs.CLSM,coupled with BiofilmQ software,enabled precise volumetric analysis,while Pyr-GC/MS provided rapid identification of chemical compositions,suggesting that they are complementary.Mass concentrations of MPs in rural road dust(14.2±6.4μg g^(−1))were greater than those in urban road dust(7.8±4.6μg g^(−1)),likely due to less stringent plastic waste management and increased agricultural plastic use in rural areas.This study builds upon prior volumetric imaging methods by enabling mass quantification of MPs under 20μm using CLSM and validating the results against Pyr-GC/MS in realworld road dust samples.展开更多
The characteristics of nonmetallic inclusions formed during steel production have a significant influence on steel performance.In this paper,studies on inclusions using confocal scanning laser microscopy(CSLM)are revi...The characteristics of nonmetallic inclusions formed during steel production have a significant influence on steel performance.In this paper,studies on inclusions using confocal scanning laser microscopy(CSLM)are reviewed and summarized,particularly the col-lision of various inclusions,dissolution of inclusions in liquid slag,and reactions between inclusions and steel.Solid inclusions exhibited a high collision tendency,whereas pure liquid inclusions exhibited minimal collisions because of the small attraction force induced by their<90°contact angle with molten steel.The collision of complex inclusions in molten steel was not included in the scope of this study and should be evaluated in future studies.Higher CaO/Al_(2)O_(3)and CaO/SiO_(2)ratios in liquid slag promoted the dissolution of Al_(2)O_(3)-based in-clusions.The formation of solid phases in the slag should be prevented to improve dissolution of inclusions.To accurately simulate the dissolution of inclusions in liquid slag,in-situ observation of the dissolution of inclusions at the steel-slag interface is necessary.Using a combination of CSLM and scanning electron microscopy-energy dispersive spectroscopy,the composition and morphological evolution of the inclusions during their modification by the dissolved elements in steel were observed and analyzed.Although the in-situ observa-tion of MnS and TiN precipitations has been widely studied,the in-situ observation of the evolution of oxide inclusions in steel during so-lidification and heating processes has rarely been reported.The effects of temperature,heating and cooling rates,and inclusion character-istics on the formation of acicular ferrites(AFs)have been widely studied.At a cooling rate of 3-5 K/s,the order of AF growth rate in-duced by different inclusions,as reported in literature,is Ti-O<Ti-Ca-Zr-Al-O<Mg-O<Ti-Zr-Al-O<Mn-Ti-Al-O<Ti-Al-O<Zr-Ti-Al-O.Further comprehensive experiments are required to investigate the quantitative relationship between the formation of AFs and inclusions.展开更多
The assembly behaviors of two low-symmetric carboxylic acid molecules(50-(6-carboxynaphthalen-2-yl)-[1,10:30,100-triphenyl]-3,400,5-tricarboxylic acid(CTTA)and 30,50-bis(6-carboxynaphthalen-2-yl)-[1,10-biphenyl]-3,5-d...The assembly behaviors of two low-symmetric carboxylic acid molecules(50-(6-carboxynaphthalen-2-yl)-[1,10:30,100-triphenyl]-3,400,5-tricarboxylic acid(CTTA)and 30,50-bis(6-carboxynaphthalen-2-yl)-[1,10-biphenyl]-3,5-dicarboxylic acid(BCBDA))containing naphthalene rings on graphite surfaces have been investigated using scanning tunneling microscopy(STM).The transformation of nanostructures induced by the second components(EDA and PEBP-C4)have been also examined.Both CTTA and BCBDA molecules self-assemble at the 1-heptanoic acid(HA)/HOPG interface,forming porous network structures.The dimer represents the most elementary building unit due to the formation of double hydrogen bonds.Moreover,the flipping of naphthalene ring results in the isomerization of BCBDA molecule.The introduction of carboxylic acid derivative EDA disrupts the dimer,which subsequently undergoes a structural conformation to form a novel porous structure.Furthermore,upon the addition of pyridine derivative PEBP-C4,N–H⋯O hydrogen bonds are the dominant forces driving the three coassembled structures.We have also conducted density functional theory(DFT)calculations to determine the molecular conformation and analyze the mechanisms underlying the formation of nanostructures.展开更多
High-temperature confocal scanning laser microscopy(HT-CSLM)is a potent methodology for investigating various phenomena in the field of metallurgy.Initially applied to the observation of solid phase transformations an...High-temperature confocal scanning laser microscopy(HT-CSLM)is a potent methodology for investigating various phenomena in the field of metallurgy.Initially applied to the observation of solid phase transformations and solidification,this method has gained traction in the field of non-metallic inclusion in steels in recent years.An overview of the experimental capabilities of HT-CSLM and the most important results of recent investigations regarding the topics of clean steel production are provided.It includes the formation of intragranular acicular ferrite(IAF)from the surface of non-metallic inclusions during the continuous cooling and heat treatment,which can be especially beneficial in the toughness of heat-affected zones of welded pieces.Furthermore,the investigation of agglomeration mechanisms of non-metallic inclusions(NMIs)in liquid steel is discussed to improve the insight into attraction forces between particles and clogging phenomena during continuous casting.Also,the dissolution of NMIs in various steelmaking slags can be observed by HT-CSLM to compare dissolution rates and mechanisms of NMI,where significant influences of temperature and chemical composition of the slag were shown.Last but not least,the experimental work regarding the interface between steel and slag is discussed,where novel techniques are currently being developed.A comprehensive summary of experimental techniques using HT-CSLM equipment to investigate different interactions of NMIs with steel and slag phases is compiled.展开更多
Over the last decade,the integra-tion of scanning tunneling mi-croscopy(STM)and electron spin resonance(ESR)spectroscopy has emerged as a powerful tool for measuring spin states of surface-adsorbed molecules.The radio...Over the last decade,the integra-tion of scanning tunneling mi-croscopy(STM)and electron spin resonance(ESR)spectroscopy has emerged as a powerful tool for measuring spin states of surface-adsorbed molecules.The radio-fre-quency voltage is a key physical quantity that influences STM-ESR spectra.However,the specific effect of radio-frequency voltage on the real-time electric current associated with STM-ESR sig-nal remains unclear.In this work,we employ the hierarchical equations of motion method to simulate the STM-ESR spectra of a single spin-1/2 surface-adsorbed molecule and track the temporal evolution of the electric current,thereby elucidating how the radio-frequency volt-age influences the features of STM-ESR spectra,the real-time electric current,and the char-acteristic frequencies conveyed by the electric current.These theoretical insights facilitate a deeper comprehension of experimental phenomena.展开更多
The morphology of antennae of Aphidoletes aphidimyza was observed with a scanning electron microscope. The results showed that both male and female were fourteen segmented, the male was approximately 2000 μm and the ...The morphology of antennae of Aphidoletes aphidimyza was observed with a scanning electron microscope. The results showed that both male and female were fourteen segmented, the male was approximately 2000 μm and the female was 1050μm. Six types of sensillae on the antenna were observed, viz. chaetica （Ch）, trichoidea （Tr）, basiconica （Ba）, cavity （Ca）, styloid （St） and circumfila （Ci） on the antennae of A. aphidimyza. Sensillae Ch had a long external-process, with a base surrounded by membranous sockets and a length of about 67.5 μm. Sensillae Tr were distally curved and inserted into a depression, 61.0μm long. Sensillae Ba were peg-like and 4.7μm long on the antennae. Sensillae Ca were pit-like in appearance and the diameter of the pit was 1.2μm. Sensilla St was found on the second sub-segment flagellum of the male antennae. The length of the sensilla was about 21 μm and the diameter was 1.5μm. The circurnfila, which are a unique type of sensilla found only on cecidomyiid antennae, formed loops around each of the antennal sub-segments, and were attached to the surface by a series of stalks. Sensilla St was only present on male antenna. The number of Ba and Tr was almost the same in both sexes. There were more Sensilla Ca on the male antenna than on the female, while there was more Ch on the female.展开更多
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
The corrosion behavior of aluminum alloys 1060 and 2A12 in a 10 mM Na2SO4＋5 mM KI solution was investigated by scanning electrochemical microscopy （SECM） and scanning electron microscopy （SEM）. The potential topo...The corrosion behavior of aluminum alloys 1060 and 2A12 in a 10 mM Na2SO4＋5 mM KI solution was investigated by scanning electrochemical microscopy （SECM） and scanning electron microscopy （SEM）. The potential topography and corrosion morphology results show that the potential of the sample surface over the same area changes with the increase of immersion time. The corrosion area becomes large, and the potential becomes more negative. The corrosion potential of the 2A12 alloy surface is lower than that of 1060 aluminum, and 2A12 alloy becomes easily corrosive. This is the reason that preferential dissolution in the boundary region of some intermetallic particles （IMPs） occurs and different dissolution behaviors are associated with different types of IMPs because of different potentials.展开更多
The activity of horseradish peroxidase at b-cyclodextrin polymer was imaged by scanning electrochemical microscopy using 3, 3', 5, 5'-tetramethylbenzide and H2O2 as the substrates.
Photoacoustic imaging is a potential candidate for in vivo brain imaging,whereas,its imaging performance could be degraded by inhomogeneous multi-layered media,consisted of scalp and skull.In this work,we propose a lo...Photoacoustic imaging is a potential candidate for in vivo brain imaging,whereas,its imaging performance could be degraded by inhomogeneous multi-layered media,consisted of scalp and skull.In this work,we propose a low-artifact photoacoustic microscopy(LAPAM)scheme,which combines conventional acoustic-resolution photoacoustic microscopy with scanning acoustic microscopy to suppress the reflection artifacts induced by multi-layers.Based on similar propagation characteristics of photoacoustic signals and ultrasonic echoes,the ultrasonic echoes can be employed as the filters to suppress the reflection artifacts to obtain low-artifact photoacoustic images.Phantom experiment is used to validate the effectiveness of this method.Furthermore,LAPAM is applied for in-vivo imaging mouse brain without removing the scalp and the skull.Experimental results show that the proposed method successfully achieves the low-artifact brain image,which demonstrates the practical applicability of LAPAM.This work might improve the photoacoustic imaging quality in many biomedical applications which involve tissues with complex acoustic properties,such as brain imaging through scalp and skull.展开更多
Development of reaction-tailored electrocatalysts is becoming increasingly important as energy and environment are among key issues governing our sustainable future.Electrocatalysts are inherently optimized for applic...Development of reaction-tailored electrocatalysts is becoming increasingly important as energy and environment are among key issues governing our sustainable future.Electrocatalysts are inherently optimized for application towards reactions of interest in renewable energy,such as those involved in water splitting and artificial photosynthesis,owing to its energy efficiency,simple fabrication,and ease of operation.In this view,it is important to secure logical design principles for the synthesis of electrocatalysts for various reactions of interest,and also understand their catalytic mechanisms in the respective reactions for improvements in further iterations.In this review,we introduce several key methods of scanning electrochemical microscopy(SECM)in its applications towards electrocatalysis.A brief history and a handful of seminal works in the SECM field is introduced in advancing the synthetic designs of electrocatalysts and elucidation of the operating mechanism.New developments in nano-sizing of the electrodes in attempts for improved spatial resolution of SECM is also introduced,and the application of nanoelectrodes towards the investigation of formerly inaccessible single catalytic entities is shared.展开更多
The ultrahigh vacuum scanning tunneling microscope(STM)was used to characterize the GaSb_(1-x)Bi_(x) films of a few nanometers thickness grown by the molecular beam epitaxy(MBE)on the GaSb buffer layer of 100 nm with ...The ultrahigh vacuum scanning tunneling microscope(STM)was used to characterize the GaSb_(1-x)Bi_(x) films of a few nanometers thickness grown by the molecular beam epitaxy(MBE)on the GaSb buffer layer of 100 nm with the GaSb(100)substrates.The thickness of the GaSb_(1-x)Bi_(x) layers of the samples are 5 and 10 nm,respectively.For comparison,the GaSb buffer was also characterized and its STM image displays terraces whose surfaces are basically atomically flat and their roughness is generally less than 1 monolayer(ML).The surface of 5 nm GaSb_(1-x)Bi_(x) film reserves the same terraced morphology as the buffer layer.In contrast,the morphology of the 10 nm GaSb_(1-x)Bi_(x) film changes to the mound-like island structures with a height of a few MLs.The result implies the growth mode transition from the two-dimensional mode as displayed by the 5 nm film to the Stranski-Krastinov mode as displayed by the 10 nm film.The statistical analysis with the scanning tunneling spectroscopy(STS)measurements indicates that both the incorporation and the inhomogeneity of Bi atoms increase with the thickness of the GaSb_(1-x)Bi_(x) layer.展开更多
Scanning transmission electron microscopy（STEM） has been shown as powerful tools for material characterization,especially after the appearance of aberration-corrector which greatly enhances the resolution of STEM. H...Scanning transmission electron microscopy（STEM） has been shown as powerful tools for material characterization,especially after the appearance of aberration-corrector which greatly enhances the resolution of STEM. High angle annular dark field（HAADF） and annular bright field（ABF） imaging of the aberration-corrected STEM are widely used due to their high-resolution capabilities and easily interpretable image contrasts. However, HAADF mode of the STEM is still limited in detecting light elements due to the weak electron-scattering power. ABF mode of the STEM could detect light and heavy elements simultaneously, providing unprecedented opportunities for probing unknown structures of materials. Atomiclevel structure investigation of materials has been achieved by means of these imaging modes, which is invaluable in many fields for either improving properties of materials or developing new materials. This paper aims to provide a introduction of HAADF and ABF imaging techniques and reviews their applications in characterization of cathode materials, study of electrochemical reaction mechanisms, and exploring the effective design of lithium-ion batteries（LIBs）. The future prospects of the STEM are also discussed.展开更多
Scanning ion conductance microscopy（SICM） is an emerging non-destructive surface topography characterization apparatus with nanoscale resolution. However, the low regulating frequency of probe in most existing modul...Scanning ion conductance microscopy（SICM） is an emerging non-destructive surface topography characterization apparatus with nanoscale resolution. However, the low regulating frequency of probe in most existing modulated current based SICM systems increases the system noise, and has difficulty in imaging sample surface with steep height changes. In order to enable SICM to have the capability of imaging surfaces with steep height changes, a novel probe that can be used in the modulated current based bopping mode is designed. The design relies on two piezoelectric ceramics with different travels to separate position adjustment and probe frequency regulation in the Z direction. To fiarther improve the resonant frequency of the probe, the material and the key dimensions for each component of the probe are optimized based on the multi-objective optimization method and the finite element analysis. The optimal design has a resonant frequency of above 10 kHz. To validate the rationality of the designed probe, microstructured grating samples are imaged using the homebuilt modulated current based SICM system. The experimental results indicate that the designed high frequency probe can effectively reduce the spike noise by 26% in the average number of spike noise. The proposed design provides a feasible solution for improving the imaging quality of the existing SICM systems which normally use ordinary probes with relatively low regulating frequency.展开更多
The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate（MTA） was studied by scanning electron microscopy（SEM）. Single-rooted huma...The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate（MTA） was studied by scanning electron microscopy（SEM）. Single-rooted human premolars（n560） were instrumented to an apical size #50/0.06 using ProF ile and treated as follows： Group 1（n510） was filled with phosphate buffered saline（PBS）; Group 2（n510） was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3（n520） was obturated orthograde with a paste of OrthoM TA（BioM TA, Seoul, Korea） and PBS; and Group 4（n520） was incubated with E. faecalis for 3 weeks and then obturated with OrthoM TA–PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material（IRM）, and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoM TA-filled roots（Groups 3 and 4）. Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots（Group 4）. Therefore, the orthograde obturation of root canals with OrthoM TA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization.展开更多
Herein,we discovered that the surface-confined condensation of boronic acid can happen spontaneously at room temperature,by comparing the kinetics of condensation of boronic acids with and without the negative sample ...Herein,we discovered that the surface-confined condensation of boronic acid can happen spontaneously at room temperature,by comparing the kinetics of condensation of boronic acids with and without the negative sample bias,we found that the negative sample bias indeed accelerates the self-condensation reaction of boronic acid.Combining with in-situ STM images and ultraviolet photoemission spectrum(UPS)analysis,a reversible adsorption mechanism model was proposed and reasonably explains the reversible electric-field-induced phase transformation.展开更多
AIM:To compare bacterial biofilm colonization in lacrimal stents following external dacryocystorhinostomy(EX-DCR),endoscopic dacryocystorhinostomy(EN-DCR),and transcanalicular dacryocystorhinostomy(TC-DCR)with multidi...AIM:To compare bacterial biofilm colonization in lacrimal stents following external dacryocystorhinostomy(EX-DCR),endoscopic dacryocystorhinostomy(EN-DCR),and transcanalicular dacryocystorhinostomy(TC-DCR)with multidiode laser.METHODS:This prospective study included 30consecutive patients with nasolacrimal duct obstruction who underwent EXT-,EN-,or TC-DCR.Thirty removed lacrimal stent fragments and conjunctival samples were cultured.The lacrimal stent biofilms were examined by scanning electron microscopy(SEM).RESULTS:Eleven(36.7%)of the 30 lacrimal stent cultures were positive for aerobic bacteria(most commonly Staphylococcus epidermidis and Pseudomonas aeruginosa).However anaerobic bacteria and fungi were not identified in the lacrimal stent cultures.Twenty-seven(90%)patients had biofilmpositive lacrimal stents.The conjunctival culture positivity after the DCR,biofilm positivity on stents,the grade of biofilm colonization,and the presence of mucus and coccoid and rod-shaped organisms did not significantly differ between any of the groups(P】0.05).However,a significant difference was found when the SEM results were compared to the results of the lacrimal stent and conjunctival cultures(P【0.001).CONCLUSION:Type of dacryocystorhinostomy(DCR)surgery did not affect the biofilm colonization of the lacrimal stents.SEM also appears to be more precise than microbiological culture for evaluating the presence of biofilms on lacrimal stents.展开更多
Objective To study the effect of ginsenoside Rb1 and total saponin of dipsacus asper on intracellular free calcium concentration mediated by β amyloid protein.So as to lay a foundation for developing effective Chines...Objective To study the effect of ginsenoside Rb1 and total saponin of dipsacus asper on intracellular free calcium concentration mediated by β amyloid protein.So as to lay a foundation for developing effective Chinese traditional medicine to treat Alzheimer’s disease.Methods The technique of laser scanning confocal microscopy combining primary cultured neurons was adopted to quantitatively analyze the change of [Ca 2+ ] i.Results The [Ca 2+ ] i of primary cultured hippocampal neurons was nmol·L -1 on basal levels.Control group showed obvious change of calcium vibration,[Ca 2+ ] i was elevated to nmol·L -1 .The peak of [Ca 2+ ] i of Rb1 group reached nmol·L -1 and was lower than that of control group .The tSDA group displayed distinct change of calcium vibration too,and [Ca 2+ ] i reached nmol·L -1 .There was a significant difference in [Ca 2+ ] i between control and tSDA group .Conclusion The research indicated that one of mechanisms by which Rb1 and tSDA protected the neurons was to maintain the balance of [Ca 2+ ] i.展开更多
基金Ministry of Science and Technology of China(Grant No.2012AA022501,2012CB720604)the National Natural Science Foundation of China(Grant No.20932001,81302626)
文摘Investigation intracellular trafficking of siRNAs following their delivery to cells is of great interest to elucidate dynamics of siRNA in cytoplasm. In this study, we present a novel confocal laser scanning microscopy （CLSM） method to evaluate a novel delivery system of 3＇-peptide-siRNA therapeutic, which was named 3＇-pAs-siRNA/CLD. This method could not only calculate the content of the intracellular 3＇-peptide-siRNA, but also quantify its co-localization with cellular substructure. We observed that 3＇-pAs-siRNA/CLD, which provided the better antitumor capability, also had a better cell uptake, endosome escape and a longer retention time in A375. This novel strategy was proved to be efficient, quantified and visualized, thus making the dynamics research of siRNA in cytoplasm clear and simplified.
基金supported by the Samsung Research Funding&Incubation Center of Samsung Electronics under Project Number SRFC-IT2401-01 and by National Research Foundation(NRF)grants(RS-2024-00462912,RS-2023-00266110,and RS-2020-NR049544)funded by the Ministry of Science and ICT(MSIT)of the Korean governmentI.K.acknowledges the NRF Sejong Science Fellowship(RS-2021-NR061797)funded by the MSIT of the Korean government.We would like to express our sincere gratitude to Yangkyu Kim for his invaluable assistance in correcting the mathematical errors in this paper.
文摘Image scanning microscopy(ISM)is a promising imaging technique that offers sub-diffraction-limited resolution and optical sectioning.Theoretically,ISM can improve the optical resolution by a factor of two through pixel reassignment and deconvolution.Multifocal array illumination and scanning have been widely adopted to implement ISM because of their simplicity.Conventionally,digital micromirror devices(DMDs)1 and microlens arrays(MLAs)2,3 have been used to generate dense and uniform multifocal arrays for ISM,which are critical for achieving fast imaging and high-quality ISM reconstruction.However,these approaches have limitations in terms of cost,numerical aperture(NA),pitch,and uniformity,making it challenging to create dense and high-quality multifocal arrays at high NA.To overcome these limitations,we introduced a novel multifocal metalens design strategy called the hybrid multiplexing method,which combines two conventional multiplexing approaches:phase addition and random multiplexing.Through numerical simulations,we demonstrate that the proposed method generates more uniform and denser multifocal arrays than conventional methods,even at small pitches.As a proof of concept,we fabricated a multifocal metalens generating 40×40 array of foci with a 3μm pitch and NA of 0.7 operating at a wavelength of 488 nm and then constructed the multifocal metalens-based ISM(MMISM).We demonstrated that MMISM successfully resolved sub-diffraction-limited features in imaging of microbead samples and forebrain organoid sections.The results showed that MMISM imaging achieved twice the diffraction-limited resolution and revealed clearer structural features of neurons compared to wide-field images.We anticipate that our novel design strategy can be widely applied to produce multifunctional optical elements and replace conventional optical elements in specialized applications.
基金supported by a National Research Foundation of Korea(NRF)grant funded by the Korean Government(Ministry of Science and ICT)(No.RS-2023-00209242).
文摘Detecting microplastics(MPs)under 20μm has been challenging,yet these tiny particles may pose significant threats to human health and the environment.They can be inhaled or ingested,potentially leading to respiratory diseases and gastrointestinal problems.This research proposed confocal laser scanning microscopy(CLSM)for identifying MPs smaller than 20μm and to support its validity by comparing results to a typical gravimetric analysis for these small MPs in road dust samples using pyrolysis-gas chromatography/mass spectrometry(Pyr-GC/MS).A total of 30 road dust samples were collected from urban areas in Seoul and 15 samples from rural regions throughout South Korea.A strong agreement was observed between the results obtained from CLSM and Pyr-GC/MS,confirming the effectiveness of both methods in measuring MPs under 20μm especially when polyolefins are dominating MPs.CLSM,coupled with BiofilmQ software,enabled precise volumetric analysis,while Pyr-GC/MS provided rapid identification of chemical compositions,suggesting that they are complementary.Mass concentrations of MPs in rural road dust(14.2±6.4μg g^(−1))were greater than those in urban road dust(7.8±4.6μg g^(−1)),likely due to less stringent plastic waste management and increased agricultural plastic use in rural areas.This study builds upon prior volumetric imaging methods by enabling mass quantification of MPs under 20μm using CLSM and validating the results against Pyr-GC/MS in realworld road dust samples.
基金supported by the National Key R&D Program(No.2023YFB3709900)the National Nature Science Foundation of China(No.U22A20171)+2 种基金China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202315)the High Steel Center(HSC)at North China University of TechnologyUniversity of Science and Technology Beijing,China.
文摘The characteristics of nonmetallic inclusions formed during steel production have a significant influence on steel performance.In this paper,studies on inclusions using confocal scanning laser microscopy(CSLM)are reviewed and summarized,particularly the col-lision of various inclusions,dissolution of inclusions in liquid slag,and reactions between inclusions and steel.Solid inclusions exhibited a high collision tendency,whereas pure liquid inclusions exhibited minimal collisions because of the small attraction force induced by their<90°contact angle with molten steel.The collision of complex inclusions in molten steel was not included in the scope of this study and should be evaluated in future studies.Higher CaO/Al_(2)O_(3)and CaO/SiO_(2)ratios in liquid slag promoted the dissolution of Al_(2)O_(3)-based in-clusions.The formation of solid phases in the slag should be prevented to improve dissolution of inclusions.To accurately simulate the dissolution of inclusions in liquid slag,in-situ observation of the dissolution of inclusions at the steel-slag interface is necessary.Using a combination of CSLM and scanning electron microscopy-energy dispersive spectroscopy,the composition and morphological evolution of the inclusions during their modification by the dissolved elements in steel were observed and analyzed.Although the in-situ observa-tion of MnS and TiN precipitations has been widely studied,the in-situ observation of the evolution of oxide inclusions in steel during so-lidification and heating processes has rarely been reported.The effects of temperature,heating and cooling rates,and inclusion character-istics on the formation of acicular ferrites(AFs)have been widely studied.At a cooling rate of 3-5 K/s,the order of AF growth rate in-duced by different inclusions,as reported in literature,is Ti-O<Ti-Ca-Zr-Al-O<Mg-O<Ti-Zr-Al-O<Mn-Ti-Al-O<Ti-Al-O<Zr-Ti-Al-O.Further comprehensive experiments are required to investigate the quantitative relationship between the formation of AFs and inclusions.
基金financially supported by the National Natural Science Foundation of China(No.22272039)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB36000000)+1 种基金the Youth Program of the Liaoning Education Department(No.LJKQZ20222280)the Jilin Chinese Academy of Sciences-Yanshen Technology Co.,Ltd.
文摘The assembly behaviors of two low-symmetric carboxylic acid molecules(50-(6-carboxynaphthalen-2-yl)-[1,10:30,100-triphenyl]-3,400,5-tricarboxylic acid(CTTA)and 30,50-bis(6-carboxynaphthalen-2-yl)-[1,10-biphenyl]-3,5-dicarboxylic acid(BCBDA))containing naphthalene rings on graphite surfaces have been investigated using scanning tunneling microscopy(STM).The transformation of nanostructures induced by the second components(EDA and PEBP-C4)have been also examined.Both CTTA and BCBDA molecules self-assemble at the 1-heptanoic acid(HA)/HOPG interface,forming porous network structures.The dimer represents the most elementary building unit due to the formation of double hydrogen bonds.Moreover,the flipping of naphthalene ring results in the isomerization of BCBDA molecule.The introduction of carboxylic acid derivative EDA disrupts the dimer,which subsequently undergoes a structural conformation to form a novel porous structure.Furthermore,upon the addition of pyridine derivative PEBP-C4,N–H⋯O hydrogen bonds are the dominant forces driving the three coassembled structures.We have also conducted density functional theory(DFT)calculations to determine the molecular conformation and analyze the mechanisms underlying the formation of nanostructures.
基金the Association SSF Strategic Mobility Grant(No.SM22-0039)theÅForsk Foundation(No.23-540)for supporting the research regarding inclusion engineering.
文摘High-temperature confocal scanning laser microscopy(HT-CSLM)is a potent methodology for investigating various phenomena in the field of metallurgy.Initially applied to the observation of solid phase transformations and solidification,this method has gained traction in the field of non-metallic inclusion in steels in recent years.An overview of the experimental capabilities of HT-CSLM and the most important results of recent investigations regarding the topics of clean steel production are provided.It includes the formation of intragranular acicular ferrite(IAF)from the surface of non-metallic inclusions during the continuous cooling and heat treatment,which can be especially beneficial in the toughness of heat-affected zones of welded pieces.Furthermore,the investigation of agglomeration mechanisms of non-metallic inclusions(NMIs)in liquid steel is discussed to improve the insight into attraction forces between particles and clogging phenomena during continuous casting.Also,the dissolution of NMIs in various steelmaking slags can be observed by HT-CSLM to compare dissolution rates and mechanisms of NMI,where significant influences of temperature and chemical composition of the slag were shown.Last but not least,the experimental work regarding the interface between steel and slag is discussed,where novel techniques are currently being developed.A comprehensive summary of experimental techniques using HT-CSLM equipment to investigate different interactions of NMIs with steel and slag phases is compiled.
基金supported by the National Natural Sci-ence Foundation of China(Nos.22203083,22425301,22393912)Strategic Priority Research Pro-gram of the Chinese Academy of Sciences(No.XDB0450101).
文摘Over the last decade,the integra-tion of scanning tunneling mi-croscopy(STM)and electron spin resonance(ESR)spectroscopy has emerged as a powerful tool for measuring spin states of surface-adsorbed molecules.The radio-fre-quency voltage is a key physical quantity that influences STM-ESR spectra.However,the specific effect of radio-frequency voltage on the real-time electric current associated with STM-ESR sig-nal remains unclear.In this work,we employ the hierarchical equations of motion method to simulate the STM-ESR spectra of a single spin-1/2 surface-adsorbed molecule and track the temporal evolution of the electric current,thereby elucidating how the radio-frequency volt-age influences the features of STM-ESR spectra,the real-time electric current,and the char-acteristic frequencies conveyed by the electric current.These theoretical insights facilitate a deeper comprehension of experimental phenomena.
文摘The morphology of antennae of Aphidoletes aphidimyza was observed with a scanning electron microscope. The results showed that both male and female were fourteen segmented, the male was approximately 2000 μm and the female was 1050μm. Six types of sensillae on the antenna were observed, viz. chaetica （Ch）, trichoidea （Tr）, basiconica （Ba）, cavity （Ca）, styloid （St） and circumfila （Ci） on the antennae of A. aphidimyza. Sensillae Ch had a long external-process, with a base surrounded by membranous sockets and a length of about 67.5 μm. Sensillae Tr were distally curved and inserted into a depression, 61.0μm long. Sensillae Ba were peg-like and 4.7μm long on the antennae. Sensillae Ca were pit-like in appearance and the diameter of the pit was 1.2μm. Sensilla St was found on the second sub-segment flagellum of the male antennae. The length of the sensilla was about 21 μm and the diameter was 1.5μm. The circurnfila, which are a unique type of sensilla found only on cecidomyiid antennae, formed loops around each of the antennal sub-segments, and were attached to the surface by a series of stalks. Sensilla St was only present on male antenna. The number of Ba and Tr was almost the same in both sexes. There were more Sensilla Ca on the male antenna than on the female, while there was more Ch on the female.
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supported by the National Natural Science Foundation of China (No.50499331)the National Science and Technology Basic Conditional Platform (No.2005DTA10400)
文摘The corrosion behavior of aluminum alloys 1060 and 2A12 in a 10 mM Na2SO4＋5 mM KI solution was investigated by scanning electrochemical microscopy （SECM） and scanning electron microscopy （SEM）. The potential topography and corrosion morphology results show that the potential of the sample surface over the same area changes with the increase of immersion time. The corrosion area becomes large, and the potential becomes more negative. The corrosion potential of the 2A12 alloy surface is lower than that of 1060 aluminum, and 2A12 alloy becomes easily corrosive. This is the reason that preferential dissolution in the boundary region of some intermetallic particles （IMPs） occurs and different dissolution behaviors are associated with different types of IMPs because of different potentials.
文摘The activity of horseradish peroxidase at b-cyclodextrin polymer was imaged by scanning electrochemical microscopy using 3, 3', 5, 5'-tetramethylbenzide and H2O2 as the substrates.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12027808,11874217,11834008,81900875,and 81770973)Natural Science Foundation of Jiangsu Province,China(Grant No.BK 20181077)。
文摘Photoacoustic imaging is a potential candidate for in vivo brain imaging,whereas,its imaging performance could be degraded by inhomogeneous multi-layered media,consisted of scalp and skull.In this work,we propose a low-artifact photoacoustic microscopy(LAPAM)scheme,which combines conventional acoustic-resolution photoacoustic microscopy with scanning acoustic microscopy to suppress the reflection artifacts induced by multi-layers.Based on similar propagation characteristics of photoacoustic signals and ultrasonic echoes,the ultrasonic echoes can be employed as the filters to suppress the reflection artifacts to obtain low-artifact photoacoustic images.Phantom experiment is used to validate the effectiveness of this method.Furthermore,LAPAM is applied for in-vivo imaging mouse brain without removing the scalp and the skull.Experimental results show that the proposed method successfully achieves the low-artifact brain image,which demonstrates the practical applicability of LAPAM.This work might improve the photoacoustic imaging quality in many biomedical applications which involve tissues with complex acoustic properties,such as brain imaging through scalp and skull.
文摘Development of reaction-tailored electrocatalysts is becoming increasingly important as energy and environment are among key issues governing our sustainable future.Electrocatalysts are inherently optimized for application towards reactions of interest in renewable energy,such as those involved in water splitting and artificial photosynthesis,owing to its energy efficiency,simple fabrication,and ease of operation.In this view,it is important to secure logical design principles for the synthesis of electrocatalysts for various reactions of interest,and also understand their catalytic mechanisms in the respective reactions for improvements in further iterations.In this review,we introduce several key methods of scanning electrochemical microscopy(SECM)in its applications towards electrocatalysis.A brief history and a handful of seminal works in the SECM field is introduced in advancing the synthetic designs of electrocatalysts and elucidation of the operating mechanism.New developments in nano-sizing of the electrodes in attempts for improved spatial resolution of SECM is also introduced,and the application of nanoelectrodes towards the investigation of formerly inaccessible single catalytic entities is shared.
基金supported by the National Natural Science Foundation of China(Nos.61474073,61874069 and 61804157).
文摘The ultrahigh vacuum scanning tunneling microscope(STM)was used to characterize the GaSb_(1-x)Bi_(x) films of a few nanometers thickness grown by the molecular beam epitaxy(MBE)on the GaSb buffer layer of 100 nm with the GaSb(100)substrates.The thickness of the GaSb_(1-x)Bi_(x) layers of the samples are 5 and 10 nm,respectively.For comparison,the GaSb buffer was also characterized and its STM image displays terraces whose surfaces are basically atomically flat and their roughness is generally less than 1 monolayer(ML).The surface of 5 nm GaSb_(1-x)Bi_(x) film reserves the same terraced morphology as the buffer layer.In contrast,the morphology of the 10 nm GaSb_(1-x)Bi_(x) film changes to the mound-like island structures with a height of a few MLs.The result implies the growth mode transition from the two-dimensional mode as displayed by the 5 nm film to the Stranski-Krastinov mode as displayed by the 10 nm film.The statistical analysis with the scanning tunneling spectroscopy(STS)measurements indicates that both the incorporation and the inhomogeneity of Bi atoms increase with the thickness of the GaSb_(1-x)Bi_(x) layer.
基金supported by the National Basic Research Program of China(Grant No.2014CB921002)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB07030200)the National Natural Science Foundation of China(Grant Nos.51522212,51421002,and 51672307)
文摘Scanning transmission electron microscopy（STEM） has been shown as powerful tools for material characterization,especially after the appearance of aberration-corrector which greatly enhances the resolution of STEM. High angle annular dark field（HAADF） and annular bright field（ABF） imaging of the aberration-corrected STEM are widely used due to their high-resolution capabilities and easily interpretable image contrasts. However, HAADF mode of the STEM is still limited in detecting light elements due to the weak electron-scattering power. ABF mode of the STEM could detect light and heavy elements simultaneously, providing unprecedented opportunities for probing unknown structures of materials. Atomiclevel structure investigation of materials has been achieved by means of these imaging modes, which is invaluable in many fields for either improving properties of materials or developing new materials. This paper aims to provide a introduction of HAADF and ABF imaging techniques and reviews their applications in characterization of cathode materials, study of electrochemical reaction mechanisms, and exploring the effective design of lithium-ion batteries（LIBs）. The future prospects of the STEM are also discussed.
基金Supported by National Natural Science Foundation of China(Grant No.51375363)
文摘Scanning ion conductance microscopy（SICM） is an emerging non-destructive surface topography characterization apparatus with nanoscale resolution. However, the low regulating frequency of probe in most existing modulated current based SICM systems increases the system noise, and has difficulty in imaging sample surface with steep height changes. In order to enable SICM to have the capability of imaging surfaces with steep height changes, a novel probe that can be used in the modulated current based bopping mode is designed. The design relies on two piezoelectric ceramics with different travels to separate position adjustment and probe frequency regulation in the Z direction. To fiarther improve the resonant frequency of the probe, the material and the key dimensions for each component of the probe are optimized based on the multi-objective optimization method and the finite element analysis. The optimal design has a resonant frequency of above 10 kHz. To validate the rationality of the designed probe, microstructured grating samples are imaged using the homebuilt modulated current based SICM system. The experimental results indicate that the designed high frequency probe can effectively reduce the spike noise by 26% in the average number of spike noise. The proposed design provides a feasible solution for improving the imaging quality of the existing SICM systems which normally use ordinary probes with relatively low regulating frequency.
基金supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2009-0086835: Dr K Y Kum)the Ministry of Science, ICT and Future Planning (2011-0014231: Dr S W Chang)supported by a grant from the Kyung Hee University in 2013 (KHU-20131045)
文摘The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate（MTA） was studied by scanning electron microscopy（SEM）. Single-rooted human premolars（n560） were instrumented to an apical size #50/0.06 using ProF ile and treated as follows： Group 1（n510） was filled with phosphate buffered saline（PBS）; Group 2（n510） was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3（n520） was obturated orthograde with a paste of OrthoM TA（BioM TA, Seoul, Korea） and PBS; and Group 4（n520） was incubated with E. faecalis for 3 weeks and then obturated with OrthoM TA–PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material（IRM）, and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoM TA-filled roots（Groups 3 and 4）. Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots（Group 4）. Therefore, the orthograde obturation of root canals with OrthoM TA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21872103,52073208).
文摘Herein,we discovered that the surface-confined condensation of boronic acid can happen spontaneously at room temperature,by comparing the kinetics of condensation of boronic acids with and without the negative sample bias,we found that the negative sample bias indeed accelerates the self-condensation reaction of boronic acid.Combining with in-situ STM images and ultraviolet photoemission spectrum(UPS)analysis,a reversible adsorption mechanism model was proposed and reasonably explains the reversible electric-field-induced phase transformation.
基金Supported by Institutional Review Board of Bagcilar Education and Research Hospital,Istanbul,Turkey(No.1852)
文摘AIM:To compare bacterial biofilm colonization in lacrimal stents following external dacryocystorhinostomy(EX-DCR),endoscopic dacryocystorhinostomy(EN-DCR),and transcanalicular dacryocystorhinostomy(TC-DCR)with multidiode laser.METHODS:This prospective study included 30consecutive patients with nasolacrimal duct obstruction who underwent EXT-,EN-,or TC-DCR.Thirty removed lacrimal stent fragments and conjunctival samples were cultured.The lacrimal stent biofilms were examined by scanning electron microscopy(SEM).RESULTS:Eleven(36.7%)of the 30 lacrimal stent cultures were positive for aerobic bacteria(most commonly Staphylococcus epidermidis and Pseudomonas aeruginosa).However anaerobic bacteria and fungi were not identified in the lacrimal stent cultures.Twenty-seven(90%)patients had biofilmpositive lacrimal stents.The conjunctival culture positivity after the DCR,biofilm positivity on stents,the grade of biofilm colonization,and the presence of mucus and coccoid and rod-shaped organisms did not significantly differ between any of the groups(P】0.05).However,a significant difference was found when the SEM results were compared to the results of the lacrimal stent and conjunctival cultures(P【0.001).CONCLUSION:Type of dacryocystorhinostomy(DCR)surgery did not affect the biofilm colonization of the lacrimal stents.SEM also appears to be more precise than microbiological culture for evaluating the presence of biofilms on lacrimal stents.
文摘Objective To study the effect of ginsenoside Rb1 and total saponin of dipsacus asper on intracellular free calcium concentration mediated by β amyloid protein.So as to lay a foundation for developing effective Chinese traditional medicine to treat Alzheimer’s disease.Methods The technique of laser scanning confocal microscopy combining primary cultured neurons was adopted to quantitatively analyze the change of [Ca 2+ ] i.Results The [Ca 2+ ] i of primary cultured hippocampal neurons was nmol·L -1 on basal levels.Control group showed obvious change of calcium vibration,[Ca 2+ ] i was elevated to nmol·L -1 .The peak of [Ca 2+ ] i of Rb1 group reached nmol·L -1 and was lower than that of control group .The tSDA group displayed distinct change of calcium vibration too,and [Ca 2+ ] i reached nmol·L -1 .There was a significant difference in [Ca 2+ ] i between control and tSDA group .Conclusion The research indicated that one of mechanisms by which Rb1 and tSDA protected the neurons was to maintain the balance of [Ca 2+ ] i.
