Scanning Electron Microscopy of Antennae of Aphidoletes aphidimyza (Diptera: Cecidomyiidae)

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.

Local thermal conductivity of polycrystalline AlN ceramics measured by scanning thermal microscopy and complementary scanning electron microscopy techniques

The local thermal conductivity of polycrystalline aluminum nitride （A1N） ceramics is measured and imaged by using a scanning thermal microscope （SThM） and complementary scanning electron microscope （SEM） based techniques at room temperature. The quantitative thermal conductivity for the A1N sample is gained by using a SThM with a spatial resolution of sub-micrometer scale through using the 3w method. A thermal conductivity of 308 W/m-K within grains corresponding to that of high-purity single crystal A1N is obtained. The slight differences in thermal conduction between the adjacent grains are found to result from crystallographic misorientations, as demonstrated in the electron backscattered diffraction. A much lower thermal conductivity at the grain boundary is due to impurities and defects enriched in these sites, as indicated by energy dispersive X-ray spectroscopy.

Probing the Nucleation and Growth Kinetics of Bismuth Nanoparticles via In-situ Transmission Electron Microscopy

The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of intermediate state structure during nucleation and growth.In this work,the evolution process of bismuth nanoparticles induced by electron beam was revealed by in-situ transmission electron microscopy(TEM)at atomic scale.The experimental results demonstrate that the size,stable surface and crystallographic defect have important influences on the growth of Bi nanoparticles.Two non-classical growth paths including single crystal growth and polycrystalline combined growth,as well as,corresponding layer-by-layer growth mechanism along{012}stable crystal plane of Bi nanoparticles with dodecahedron structure were revealed by in-situ TEM directly.These results provide important guidance and a new approach for in-depth understanding of the nucleation and growth kinetics of nanoparticles.

Scanning Electron Acoustic Microscopy of GaInAsSb by Metalorganic Chemical Vapor Deposition

Scanning electron acoustic microscopy (SEAM) is a new technique for imasing and characterization ofthermal, elastic and pyroelectric property variations on a microscale resolution. The signal generation mechanisms and the application of scanning electron acoustic microscopy in GalnAsSb alloy grown by MOCVD wereinvestigated. Defects below the surface of GalnAsSb alloy were found by SEAM images and cathodelumi-nescence. The results show that electronacoustic imaging has its own features over secondary electron imag-ing.

50 years of scanning electron microscopy of bone——a comprehensive overview of the important discoveries made and insights gained into bone material properties in health,disease,and taphonomy

Bone is an architecturally complex system that constantly undergoes structural and functional optimisation through renewal and repair.The scanning electron microscope (SEM) is among the most frequently used instruments for examining bone.It offers the key advantage of very high spatial resolution coupled with a large depth of field and wide field of view.Interactions between incident electrons and atoms on the sample surface generate backscattered electrons,secondary electrons,and various other signals including X-rays that relay compositional and topographical information.Through selective removal or preservation of specific tissue components (organic,inorganic,cellular,vascular),their individual contribution(s) to the overall functional competence can be elucidated.With few restrictions on sample geometry and a variety of applicable sample-processing routes,a given sample may be conveniently adapted for multiple analytical methods.While a conventional SEM operates at high vacuum conditions that demand clean,dry,and electrically conductive samples,non-conductive materials (e.g.,bone) can be imaged without significant modification from the natural state using an environmental scanning electron microscope.This review highlights important insights gained into bone microstructure and pathophysiology,bone response to implanted biomaterials,elemental analysis,SEM in paleoarchaeology,3D imaging using focused ion beam techniques,correlative microscopy and in situ experiments.The capacity to image seamlessly across multiple length scales within the meso-micro-nano-continuum,the SEM lends itself to many unique and diverse applications,which attest to the versatility and user-friendly nature of this instrument for studying bone.Significant technological developments are anticipated for analysing bone using the SEM.

Scanning transmission electron microscopy: A review of high angle annular dark field and annular bright field imaging and applications in lithium-ion batteries

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.

Bacterial entombment by intratubular mineralization following orthograde mineral trioxide aggregate obturation: a scanning electron microscopy study

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.

Comparison of scanning electron microscopy findings regarding biofilm colonization with microbiological results in nasolacrimal stents for external, endoscopic and transcanalicular dacryocystorhinostomy

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.

Scanning electron microscopy coupled with energydispersive X-ray spectrometry for quick detection of sulfuroxidizing bacteria in environmental water samples

Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.

Ultrafast photoemission electron microscopy:A multidimensional probe of nonequilibrium physics

Exploring the realms of physics that extend beyond thermal equilibrium has emerged as a crucial branch of condensed matter physics research.It aims to unravel the intricate processes involving the excitations,interactions,and annihilations of quasi-and many-body particles,and ultimately to achieve the manipulation and engineering of exotic non-equilibrium quantum phases on the ultrasmall and ultrafast spatiotemporal scales.Given the inherent complexities arising from many-body dynamics,it therefore seeks a technique that has efficient and diverse detection degrees of freedom to study the underlying physics.By combining high-power femtosecond lasers with real-or momentum-space photoemission electron microscopy(PEEM),imaging excited state phenomena from multiple perspectives,including time,real space,energy,momentum,and spin,can be conveniently achieved,making it a unique technique in studying physics out of equilibrium.In this context,we overview the working principle and technical advances of the PEEM apparatus and the related laser systems,and survey key excited-state phenomena probed through this surface-sensitive methodology,including the ultrafast dynamics of electrons,excitons,plasmons,spins,etc.,in materials ranging from bulk and nano-structured metals and semiconductors to low-dimensional quantum materials.Through this review,one can further envision that time-resolved PEEM will open new avenues for investigating a variety of classical and quantum phenomena in a multidimensional parameter space,offering unprecedented and comprehensive insights into important questions in the field of condensed matter physics.

IDENTIFICATION OF MARINE AEROSOL COMPONENT BY COMBINED NAA AND SCANNING ELECTRON MICROSCOPY WITH X—RAY ANALYSIS

The concentrations of 30 elements in aerosol particles collected in western Pacific ocean have been determined by INAA. The crustal element concentrations decrease with increasing distance from land over the remote area close to Asia land and fluctuate around its average value over the remote ocean area. The volatile elements exhibite average atmospheric concentrations that are higher than those expected from the flux of seasalt or the continental dust. In order to identify marine aerosol component originating from the continent or ocean, the aerosol particles are examined by scanning electron microscopy combined with energy dispersive X-ray spectroscopy. Particle phase structure shows that the crustal aerosol particles are not present internal mixtures with seasalt aerosol, and it also proves the long-range transport of crustal elements from continent to ocean.

Capturing the non-equilibrium state in light–matter–free-electron interactions through ultrafast transmission electron microscopy

Ultrafast transmission electron microscope(UTEM) with the multimodality of time-resolved diffraction, imaging,and spectroscopy provides a unique platform to reveal the fundamental features associated with the interaction between free electrons and matter. In this review, we summarize the principles, instrumentation, and recent developments of the UTEM and its applications in capturing dynamic processes and non-equilibrium transient states. The combination of the transmission electron microscope with a femtosecond laser via the pump–probe method guarantees the high spatiotemporal resolution, allowing the investigation of the transient process in real, reciprocal and energy spaces. Ultrafast structural dynamics can be studied by diffraction and imaging methods, revealing the coherent acoustic phonon generation and photoinduced phase transition process. In the energy dimension, time-resolved electron energy-loss spectroscopy enables the examination of the intrinsic electronic dynamics of materials, while the photon-induced near-field electron microscopy extends the application of the UTEM to the imaging of optical near fields with high real-space resolution. It is noted that light–free-electron interactions have the ability to shape electron wave packets in both longitudinal and transverse directions, showing the potential application in the generation of attosecond electron pulses and vortex electron beams.

Study of a Novel Small Caliber Vascular Graft in a Canine Model with Optical and Scanning Electron Microscopy

A novel biological small-diameter vascular graft was evaluated in a canine model. 3 cm long segments with 4 mm I.D. were implanted end-to-end in the carotid position of 12 dogs for 6 months. Color Doppler sonography was performed at the first week post-operation, and angiography was then administered to 9 grafts at 4th week, 12th week and 24th week respectively to monitor the graft pantency and blood flow characteristics. Vascular samples containing the grafts were collected at 1st week, 8th week, 12th week and 24th week after implantation. Morphological changes of the grafts were observed by optical and scanning electron microscopic (SEM) studies and compared with that of the original prosthesis and the normal host vessel. All grafts were patent throughout the experiment except one graft. Histopathology and SEM demonstrated both a nearly complete inner capsule of varied thickness lining the graft luminal surface and connective tissue adventitia formation at one-week post-operation. The neointima became confluent at 8 weeks and then compact but had no signs of hyperplasia up to 12 weeks; meanwhile on the neointimal surface newly grown endothelial-like cells were migrating from the stoma to the middle portion. The grafts also illustrated endothelialization in many “islands” in the mid-segment luminal surface of the grafts. In addition, the closer distance the cells towards the stoma were, the more morphological similarity the cells with the normal endothelial were. Taken together, the biological vascular graft remained patent for 24 weeks as a carotid prosthesis, characterized by the early and complete neointima formation plus endothelialization starting before 12 weeks post grafting. Therefore, the graft seems suitable for reconstruction of vascular lesions in dogs. Further studies may be carried out to extend the graft application for the clinical use.

Scanning Electron Microscopy(SEM) Observations of Antennal Sensilla of Chrysopa pallens Rambur(Neuroptera：Chrysopidae)

[Objectives]The paper was to provide background information for ongoing research on relationship between smell and behavior of the green lacewing Chrysopa pallens（ Rambur）（ Neuroptera： Chrysopidae）. [Methods]The submicroscopic structure of antennal sensilla of C. pallens was examined using scanning electron microscopy. [Results]Antennae of female and male C. pallens were linear in shape and（ 1. 52 ± 0. 08） and（ 1. 58 ± 0. 23） cm in length,respectively. The scape and pedicel were composed of single sub-segment,while the flagellum consisted of 116 sub-segments,on which most sensilla distributed. The flagella of female and male antennae were（ 1. 44 ± 0. 04） and（ 1. 47 ± 0. 13） cm in length,respectively. Nine morphological sensilla types were recorded in both sexes,including four types of highly abundant and widely distributed sensilla trichodea（ ST Ⅰ,ST Ⅱ,ST Ⅲ and ST Ⅳ）,three types of sensilla basiconica（ SB Ⅰ,SB Ⅱ,and SB Ⅲ）,and one of each type of sensilla chaetica and B9 hm bristles. Although the shape,structure,numbers,and distribution of antennae of females and males were basically similar,major differences were recorded between the sexes in the length of some sensilla types. Both the ST Ⅲ and SB Ⅰ in female adults were significantly longer than that in male ones. Notably,SB Ⅱ was found only in female. [Conclusions]The paper laid a foundation for revealing the relationship between smell and behavior,playing a crucial role in promoting the important biological control effect of C. pallens in farmland ecological system.

Ultrastructural Analysis of the Ontogenetic Development of Shoot Induced from Embryonic Axes of Costa Rican Bean Varieties (<i>Phaseolus vulgaris</i>L.) under <i>in Vitro</i>Conditions by Scanning Electronic Microscopy

Common bean (Phaseolus vulgaris L.) is an economic important crop and one of the major grain legumes for human consumption in Latin America, Africa and Asia. A morphological study of shoot induced from embryonic axes development in four Costa Rican bean varieties (Brunca, Huetar, Guaymi and Bribri) cultivated on MS media with or without 5 mg·L–1 de N6-benzylaminopurine (BAP) by scanning electron microscopy (SEM) was developed in the present work. Micrographs showed similarities and differences in the ultrastructure of the apical dome, epidermal surface, stomata and different types of trichomes in the varieties cultivated on organogenesis media. Genotypes with advantageous morphological characteristics for genetic transformation, in particular an exposed apical dome, were identified. This work will contribute to the optimization of the in vitro regeneration of four common bean varieties.

OBSERVATION AND ANALYSIS OF BLOOD CONTACTING SURFACE OF LEFT VENTRICULAR ASSIST DEVICE WITH SCANNING ELECTRON MICROSCOPY

Thrombus formation in the artificial heart blood pump is a complex problem. The most important factor of thrombosis in the blood pump is the quality of blood contacting surface which is related to hemocompatibility of materials and micromorphololgy or roughness of the surface. So it is necessary to understand the morphology of the surface inside of blood pump in order to develop and improve a good quality blood pump. The authors observed and analysed the inner surface of blood pumps (both preimplanted and postimplanted) with scanning electron microscopy (SEM) providing a means for evaluating the blood pumps and for developing good quality of blood pumps. It was observed that there were four kinds of surface defects on the inner surface of the blood pumps: air bubble domes, open bubble craters, contaminated dust and gel particles. Microcrakes had also been found on the diaphragm of the postimplanted pump. But in the newly improved blood pump that had been imlanted for 16 days, there were few defects on the blood contacting surface, and only a little fibrinous layer observed. It could be considered that the current design and modifications are reasonable. Since some problems associated with the surface defects and thrombosis still existed, further improvement in fabrication process and quality control procedures with SEM are under way.

MORPHOLOGICAL CHANGES OF RATS MUSCLES AT VARIOUS POSTMORTEM INTERVALS BY SCANNING ELECTRON MICROSCOPY

The aim of this study was to observe the morphological changes of muscle in the process of rigor mortis. The quadriceps of 40 rats at various postmortem intervals were observed under the scanning electron microscope(SEM) and the light microscope by phosphotungstic acid haematoxylin(PTAH) stain. The results showed that the striations of muscle were blurred within 4 h, but they became apparent from 6 h to 24 h after death. The authors suggest that this phenomenon be associated with the increased resistance of muscle against the postmortal changes. The observations by scanning electron microscopy and light microscopy have revealed that the muscles do contract in the process of rigor mortis because the distance between two Z lines shortens and the I band narrows, compared with those in anaesthetised animals. The basic biochemical process for the formation of rigor mortis is the same as that of muscle contraction except that the former happens postmortem and the latter antemortem.

Study of the bones tissue reparation using nanostructured titanium implants with hydroxylapatite coatings by scanning electron microscopy

A method of medical implants (biocomposites) preparation based on nanostructured titanium with nanocrystalline bioactive hydroxylapatite coatings is developed. The operative treatment using these implants improves the regeneration of bone tissue for rats, as compared to the “false-operated” animals. The morphological data at 7, 14, 21, 45 days are obtained by means of scanning electron microscopy and discussed.

Neutron Activation Analysis and Scanning Electron Microscopy of Phytoplankton in the Coastal Zone of Crimea (The Black Sea)

The physiology and ecology of planktonic organisms are influenced by the concentration, chemical speciation and resulting bioavailability of some trace metals. The determination of the elemental structure of phytoplankton is important for interpretation of physiological and functional states of coastal ecosystems. The present study is focused on the structure and elemental composition of the phytoplankton assemblages from the different coastal zones by instrumental neutron activation analysis (INAA), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). For the first time these complementary techniques were simultaneously applied to study the Black Sea phytoplankton. The concentrations of 45 elements in the coastal phytoplankton communities used as bioindicator of inorganic contamination of the Black Sea coastal area near Sevastopol, Ukraine, were determined. Phytoplankton samples were collected by total tows of the plankton net with 35 μm pore size at 3 stations situated in polluted and relatively pristine water areas of the Sevastopol coastal zone during autumn period of the phytoplankton growth. The concentration of Mg, Al, Sc, Ti, V, Mn, As, Rb, Ba, Th and Fe, Cr increases exponentially from relatively pristine station to more polluted station and 10-times and 3-times greater, respectively, in the phytoplankton of the Sevastopol Bay. The rare-earth elements have relatively the same concentration values less than 1 μg/g and tend to accumulate in the phytoplankton from the polluted station in the Sevastopol Bay. The obtained results are in a good agreement with the elemental concentration data in the oceanic plankton, plankton communities from the White Sea and the Black Sea. Using energy-dispersive X-ray spectrometry the mineral particles of unknown origin and impurities of copper (0.42% by weight) in the phytoplankton at the polluted station and zinc (0.57% by weight) at the relatively pristine station were determined.

Visualization of atomic scale reaction dynamics of supported nanocatalysts during oxidation and ammonia synthesis using in-situ environmental(scanning) transmission electron microscopy

Reaction dynamics in gases at operating temperatures at the atomic level are the basis of heterogeneous gas-solid catalyst reactions and are crucial to the catalyst function.Supported noble metal nanocatalysts such as platinum are of interest in fuel cells and as diesel oxidation catalysts for pollution control,and practical ruthenium nanocatalysts are explored for ammonia synthesis.Graphite and graphitic carbons are of interest as supports for the nanocatalysts.Despite considerable literature on the catalytic processes on graphite and graphitic supports,reaction dynamics of the nanocatalysts on the supports in different reactive gas environments and operating temperatures at the single atom level are not well understood.Here we present real time in-situ observations and analyses of reaction dynamics of Pt in oxidation,and practical Ru nanocatalysts in ammonia synthesis,on graphite and related supports under controlled reaction environments using a novel in-situ environmental(scanning) transmission electron microscope with single atom resolution.By recording snapshots of the reaction dynamics,the behaviour of the catalysts is imaged.The images reveal single metal atoms,clusters of a few atoms on the graphitic supports and the support function.These all play key roles in the mobility,sintering and growth of the catalysts.The experimental findings provide new structural insights into atomic scale reaction dynamics,morphology and stability of the nanocatalysts.