Applied Microscopy最新文献

Electron ptychography has emerged as a powerful computational imaging technique using four-dimensional scanning transmission electron microscopy, greatly exceeding the resolution limits of conventional electron microscopes by quantitative phase retrieval. This paper presents recent algorithmic developments and technological requirements for detectors used in electron ptychography, as well as applications in different fields of nanoscience. The application range covers high-resolution imaging of beam-sensitive specimens, light element detection, and three-dimensional reconstruction, making electron ptychography a versatile technique for materials characterization.

This study investigated the anatomy and histology of the olfactory organ of the Korean amur goby Rhinogobius brunneus from Jeonjucheon stream. This species lives in shallow, stagnant, and intermittently low-oxygenated streams, reservoirs, and ponds affected by seasonal rainfall. Anatomically, its olfactory organ consisted of a short tubular anterior nostril, a posterior nostril, a single longitudinal lamella, and two accessory nasal sacs (ethmoidal and lacrymal sacs). Its single lamella structure resembles other gobiid fishes with a simplified olfactory surface. Histologically, the sensory epithelium comprised olfactory receptor neurons, supporting cells, and basal cells, while the non-sensory epithelium contained stratified epithelial cells, basal cells, and mucous cells. In particular, the mucous cells stained intensely red with Hematoxylin and eosin and Masson’s trichrome, indicating proteinaceous granular mucins rich in glycoproteins; such secretions likely protect the epithelium against particles, toxins, and low-oxygenated freshwater. Overall, the goby’s olfactory organ exhibits traits uniquely adapted to stagnant and hypoxic conditions.

Two-dimensional (2D) van der Waals materials possess structural degrees of freedom that set them apart from conventional bulk crystals and strongly influence their physical properties. Such freedom, enabled by the weak interlayer bonding, permits stacking, twisting, and lateral sliding of layers, leading to structural variations such as out-of-plane corrugations, layer-number–dependent electronic and optical responses, and interlayer registry variations that produce stacking domains with distinct functionalities. Capturing and understanding these variations is essential for linking structure to function. Transmission electron microscopy (TEM) offers complementary approaches for this purpose: electron diffraction provides quantitative crystallographic fingerprints, while dark-field (DF) imaging translates selected diffraction information into spatial maps of local structure. When combined, these techniques can resolve complex structural modulations across multiple length scales and under diverse experimental conditions. Recent advances have extended diffraction and DF imaging into in-situ and operando regimes, enabling real-time observation of domain reconfiguration, phase transitions, and polarization switching under external stimuli. This review discusses how these methods are applied to 2D van der Waals materials to reveal structural degrees of freedom and illustrates their unique capability to directly connect structural evolution to functional behavior.

Smart microscopy is a new imaging approach that involves rapid imaging, prediction of important subregions, then selective re-imaging. This approach has been validated in reducing imaging beam time in electron microscopy connectomics, but the speedup depends on various imaging workflow parameters. Here we present the first runtime analysis of traditional vs. smart microscopy and show how these parameters can magnify, or diminish potential time savings. We provide a GUI application that calculates the theoretical time savings of smart microscopy from user input parameters describing their imaging workflow. Finally, we measure end-to-end runtime of SmartEM acquisition on an electron microscope to demonstrate two strategies for faster acquisition: mixed-precision neural networks and parallelization of microscope and support computer operations.

The non-sticky spiral silk, which typically serves as a temporary structural component in most orb-weaving spiders, functions as a permanent scaffold in the golden orb-web spider (Trichonephila clavata). Composed of double strands approximately 4 μm in diameter, the non-sticky spiral forms robust extended junctions exceeding 200 μm in radius. The muscular cell layer observed within the pyriform gland facilitates the active extrusion of pyriform fibers and cement, enabling efficient wrapping at the junctions. These robust junctions stand in stark contrast to the loose, droplet-mediated adhesion seen in sticky spirals, allowing the non-sticky spiral to enhance web stability and effectively prevent damage expansion. Furthermore, the non-sticky spiral plays an important role in localized web repair by replicating the original web's loop patterns to restore damaged areas. These findings suggest that the non-sticky spiral stabilizes the wide intervals between radii in the lower hub region, providing enhanced resistance to external forces and repairing structural damages. The results also demonstrate the evolutionary significance of utilizing non-sticky spiral as a permanent component, facilitating the construction and maintenance of large, densely structured orb webs.

Pristine and Fe (1.0, 2.0, 3.0, 4.0 and 5.0 mol%) doped Polyvinyl alcohol/Methacrylic Acid- Ethyl Acrylate (PVA/MAA:EA) polymer blend films were prepared by solution casting method and characterized by various techniques. TGA analysis validates the occurrence of three distinct weight loss steps attributed to removal of volatile substances from both the surface and interior of the material, as well as the decomposition of the polymer. X-ray diffraction (XRD) investigations confirm a decrease in crystallinity as the dopant concentration increases. Scanning electron microscope (SEM) micrographs show uniform morphology. Fourier transform infrared (FTIR) spectrum exhibits bands characteristic of stretching and bending vibrations of O–H, C–H, C = C and C–O groups and the changes in the spectrum with dopant concentration show the miscibility of dopant with the polymer blend. UV–visible absorption spectra demonstrate the decrease of optical band gap as the concentration of Fe rises and exhibit absorption bands corresponding to the transitions ⁶A_1g → ⁴A_1g and ⁶A_1g → ⁴T_2g of Fe³⁺ ions in distorted octahedral symmetry. Electron paramagnetic resonance (EPR) spectra exhibit resonance signals one around g = 2.12 attributed to Fe³⁺ ions in the distorted octahedral environment and the other signal around g = 6.8 due to Fe³⁺ ions in rhombic symmetry. The number of spins engaged in the resonance as a function of dopant concentration is determined through EPR analysis and the paramagnetic susceptibility is estimated. The conductivity of Fe³⁺ ions doped PVA/MAA:EA polymer blend films increases with an increase in Fe³⁺ concentration, which is explained in terms of an increase in the amorphous phase due to doping.

Accurate determination of three-dimensional (3D) atomic structures is crucial for understanding and controlling the properties of nanomaterials. Atomic electron tomography (AET) offers non-destructive atomic imaging with picometer-level precision, enabling the resolution of defects, interfaces, and strain fields in 3D, as well as the observation of dynamic structural evolution. However, reconstruction artifacts arising from geometric limitations and electron dose constraints can hinder reliable atomic structure determination. Recent progress has integrated deep learning, especially convolutional neural networks, into AET workflows to improve reconstruction fidelity. This review highlights recent advances in neural network-assisted AET, emphasizing its role in overcoming persistent challenges in 3D atomic imaging. By significantly enhancing the accuracy of both surface and bulk structural characterization, these methods are advancing the frontiers of nanoscience and enabling new opportunities in materials research and technology.

Negative staining electron microscopy remains a valuable tool for structural biology, particularly for initial characterization of large protein complexes. However, the limitations of single staining methods often result in incomplete structural information. Here, we present a novel multi-stain approach for negative staining electron microscopy, applied to the structural analysis of the pyruvate dehydrogenase E2 (PDH E2) complex. By integrating data from three distinct staining agents (uranyl acetate, ammonium phosphotungstate, and ammonium molybdate) we demonstrate significant improvements in structural resolution and detail. Our method improved the resolution from a range of approximately 27–31 Å (observed with individual stains) to about 21.7 Å in the combined dataset. This enhancement facilitated a clearer visualization of the complex’s icosahedral symmetry and allowed for a more precise determination of the overall shape and domain organization of the PDH E2 complex. The multi-stain approach revealed complementary structural information, with each stain highlighting different aspects of the protein complex. Uranyl acetate provided excellent overall contrast, while ammonium phosphotungstate and molybdate offered enhanced visibility of specific structural elements. The integration of these complementary data sets resulted in a more comprehensive structural model. Our findings suggest that this multi-stain negative staining approach can be a powerful tool for enhancing low-resolution structural information of large protein complexes, bridging the gap between initial characterization and high-resolution studies. This method holds promise for improving our understanding of challenging macromolecular assemblies and may serve as a valuable precursor to more advanced structural biology techniques.

Diatoms are microalgae with a significant ecological role as primary producers, contributing approximately 20% of global carbon fixation. They exhibit remarkable evolutionary success and biodiversity, with approximately 18,000 species identified globally, including 2,323 species reported in Korea. In this study, we identified 13 unrecorded diatom species from various freshwater environments in Korea, including rivers, streams, reservoirs, and lagoons. Among these, the genera Brachysira, Gomphonella, and Staurophora were recorded for the first time in Korea, expanding the national species list. The unrecorded species included 12 pennate diatoms (Adlafia multnomahii, Encyonema cespitosum, Placoneis symmetrica, Gomphonema incognitum, Rhoicosphenia baltica, Brachysira vitrea, Gomphonella fogedii, Hantzschia psammicola, Hyalosynedra laevigata, Pseudostaurosira parasitica, Tryblionella calida, and Staurophora amphioxys) and one centric diatom (Discostella lacuskarluki). Morphological and ultrastructural analyses were conducted using scanning electron microscopy to characterize these species. This research highlights the biodiversity of Korean diatoms and their potential applications in environmental monitoring and nanotechnology, contributing to the broader understanding of diatom taxonomy and ecology.

Optical clearing of apple tissues was performed to observe the pre-penetration behavior of Botryosphaeria dothidea. Mature red fruits and two-year-old twigs were artificially inoculated with the fungal conidia. Fruit epidermis and twig cork tissues were excised and immersed overnight in an ethanol-chloroform solution amended with trichloroacetic acid. Lactophenol cotton blue was used to stain the fungus on the host surfaces. The morphology and behavior of the inoculated B. dothidea could be clearly observed in the two types of optically cleared specimens. The conidia showed either monopolar or bipolar germination, leading to the emergence of germ tubes from one or both conidial ends. Conidia formed appressoria at the terminal ends of germ tubes. They appeared round, hook-shaped, and irregular-shaped in two-dimensional light micrographs. Multiple appressoria were observed on the suberized phellem cells in twig lenticels. These results suggest that the optical clearing technique and fungal staining were effective in partially decolorizing apple tissues and revealing the fungal structures on the host surfaces.