Applied Microscopy最新文献

Gamma prime (γ′) precipitates and grain boundary (GB) carbides govern the high-temperature performance of Ni-based superalloys, and their reliable quantification is essential for microstructural evaluation and alloy development. However, conventional etching procedures are often transferred between alloys without considering composition-dependent changes in γ′ size and fraction or carbide population, which can cause unstable contrast, γ-matrix damage, and unreliable image-based interpretation. Here, we establish composition-tailored etching conditions for Haynes^® 282 (γ′ ~23 nm) and two model alloys with modified Al–Ti and Nb–Ta contents, and evaluate their suitability for phase-selective Scanning electron microscopy (SEM) imaging. After identical mechanical preparation, γ′ precipitates in Haynes^® 282 and Model alloy 1 are clearly revealed using a nitric-acid etchant, whereas the same condition fails in Model alloy 2 with reduced Al and Ti, where much finer γ′ precipitates form. An HF-containing mixed-acid etchant is introduced to obtain stable γ′ contrast in Model alloy 2 without excessive surface relief. GB carbides also show composition-dependent responses. In Haynes^® 282, Cr-rich M₂₃C₆-decorated boundaries are revealed by nitric acid, whereas Nb/Ta-containing model alloys require chloride-based etchants to expose both MC and M₂₃C₆ carbides. These protocols provide reproducible, phase-selective SEM contrast for robust image-based quantification.

The internal structures of fractured white charcoal were investigated using a scanning electron microscope. The charcoal was fractured using a razor blade and hammer, gold-coated, and observed under the electron microscope. Both embolized and conductive vessels coexisted across the transverse surfaces of the fractured charcoal. Vessels were predominantly ellipsoidal, with an average diameter of approximately 250 μm. Embolized vessels exhibited membranous tyloses within their lumens. The presence of ring-porous wood, axial parenchyma cells, and xylem fibers within the secondary xylem implies that the white charcoal was produced from a Quercus species. Fungal hyphae were observed to proliferate, branch, and sporulate on the secondary cell walls of vessels. The conidiogenous cells and conidia closely resembled those of a fungal pathogen known to cause oak wilt disease in South Korea. Fungal hyphae were also found within the pits of the secondary cell walls. These observations suggest that the oak tree used for charcoal production in this study may have been diseased. These results indicate that wood structures are preserved through the white charcoal production process, allowing the observation of fungal structures within the host.

Plastic deformation in Mg alloys requires a full understanding of slip activity and intergranular interactions, which determine mechanical behavior and strain localization. Electron backscatter diffraction (EBSD) has emerged as a versatile technique to map crystallographic orientations, slip systems, and lattice rotations, permitting the systematic analysis of deformation mechanisms across polycrystalline aggregates. The coupling of EBSD with metrics including Schmid factors, ingrain misorientation axes, and slip-transfer criteria permits a quantitative assessment of slip compatibility and the role of grain boundaries in strain accommodation. Limitations related to conventional 2D surface characterization create a growing need for novel three-dimensional techniques that can accurately represent grain boundary geometry as well as complex intergranular deformation pathways. A focused review of such methodologies will compile current knowledge on these methods and their capabilities and limitations, guiding future investigations toward a deeper understanding of microstructure-mechanics relationships in Mg alloys.

Antonie van Leeuwenhoek (1632–1723) transformed observation into science through the power of a single handmade lens. His work emerged from the visual culture of seventeenth-century Delft, where craftsmanship, optics, and artistic precision intersected. While Robert Hooke’s compound microscope introduced the idea of microscopic visualization, Leeuwenhoek’s single-lens instruments achieved far superior magnification and resolution by minimizing optical interfaces. Using these deceptively simple devices, he documented the first observations of free-living microorganisms, fungal hyphae, red blood cells, capillary flow, oral bacteria, and spermatozoa in more than two hundred letters to the Royal Society of London.

But his investigations reached far beyond microbiology. Leeuwenhoek also examined the barbed structure of the bee sting, the ordered vessels of ash wood, and the geometric microstructure of crystals and salts—demonstrating that hidden organization pervades both living and non-living matter. These studies established microscopy as a universal investigative tool, capable of unifying biology, medicine, botany, and early materials science under a single optical principle.

Leeuwenhoek’s work marks one of the earliest examples of how rigorous observation can redefine scientific domains. His use of a home-crafted single lens created an empirical foundation for biological microscopy that persists to this day. The legacy of his minimalist optical design also survives in the digital age: modern clip-on smartphone microscopes and paper-based platforms such as the Foldscope reproduce the same single-lens principle through micro-optics mounted directly onto digital sensors.

Three and a half centuries later, his work continues to remind us that new worlds do not emerge from new theories alone, but from new ways of seeing.

Nanotopographic control of cell behavior offers great potential in designing biomimetic scaffolds for cell therapy. However, the behavior of cells on different nanotopographies is not fully understood. In this study, we investigated the effect of nanostructures on human adipose-derived stem cells (ASCs) by directly comparing nanopillar and nanopit arrays. Morphological changes, cell viability and early osteogenic differentiation of ASCs have been analyzed on the nanostructures. Nanopit arrays were found to increase cell areas and promote early osteogenic differentiation more than nanopillar arrays. Analysis of focal adhesion (FA) formation indicated a larger increase in total area as well as the number of FAs during cell spreading on nanopit arrays. The maturation of FA is related to cellular traction forces, which are known to stimulate osteogenic induction through the RhoA-ROCK pathway. We conclude that ASCs can spread more on the nanopit array than on the nanopillar array due to the presence of continuous adhesive paths on the nanopit array, which is associated with increased expression of RUNX2 as an early osteogenic marker. Our results suggest that a connected path in nanopit arrays plays a critical role in controlling stem cell behavior compared to nanopillar arrays. A comparative understanding of nanostructures can provide a guideline for designing an artificial substrate for osteogenesis and tissue engineering.

The effective method for eliminating the Moiré fringes in the MC nanoprecipitates in the austenite matrix was studied. Considering the dynamic diffraction between the matrix and precipitate, the spots originating from the Moiré pattern were selected in the fast Fourier transform (FFT) pattern. The Moiré fringe image was extracted by performing inverse FFT(IFFT) of the selected spots. Subtracting the Moiré fringe contribution from the original image intensity reveals the veiled lattice fringes of MC carbide in the austenite matrix. The image was compared and discussed with the IFFT image of the direct selection of the matrix + MC FFT patterns. The suggested method was applied to strain measurement in the MC carbide-containing area using the geometrical phase analysis. Compared with the result obtained from the raw image containing Moiré fringes, the applied method shows artifact-free strain distribution in the MC carbide. The process was applied to the inclined twin interface in BCC steel. The lattice fringe in the overlapping area shows a more detailed lattice feature. This novel study sheds light on the veiled crystal structure and strain distribution under various conditions where more than two lattice fringes overlap.

We established a correlative workflow combining X-ray microscopy (XRM) and transmission electron microscopy (TEM) to investigate the ultrastructure of zebrafish neuromasts. Zebrafish tissues were processed using conventional TEM embedding protocols and first imaged with XRM to obtain three-dimensional information and to localize the neuromast within resin blocks. The XRM previews enabled accurate trimming and rapid identification of target regions, reducing the need for repeated semi-thin sectioning and toluidine blue staining. Subsequent TEM analysis revealed ultrastructural details including cell-to-cell contacts and organelle morphology. Our study demonstrates that integration of XRM with TEM increases efficiency, minimizes tissue loss, and improves orientation accuracy for ultrastructural analysis. This correlative approach provides a valuable workflow for volume electron microscopy, applicable to the observation of the neuromast and various other tissues.

Release of prosthesis debris at the tissue-implant interface is a major cause of aseptic loosening, a phenomenon that requires premature replacement of the prosthesis. The main objective of this paper is to propose a step-structured modus operandi for a reliable scanning electron microscopy (SEM) analysis of debris released from prostheses into the surrounding tissues. Following a proven methodology for the analysis of this wear debris would allow research and hospital laboratories to reduce time and obtain results associated with a common protocol and consequently, more comparable results. For developing the methodology, we chose the clinical case of a hip prosthetic revision, in which a Cr-Co head misalignment caused the wearing out of the polyethylene acetabular insert and a partial wear of the Ti-6Al-4 V acetabular cup. Samples of periprosthetic tissues, after being partially digested in a KOH basic solution, were investigated in vivo and in situ with SEM observations and Energy Dispersive X-rays Spectroscopy (EDXS) analyses. Although developed from a specific case study, this methodology is compatible and applicable to other standard cases as well. Regarding the set of samples we selected, a complete set of micro- and nano-structural analysis, compositional spectra and high-resolution images have been acquired, showing the morphology of the debris involved, and the agglomeration phenomena occurring in the tissue. The proposed protocol complements previous studies on tribological phenomena, underlying debris production at the tissue-prosthesis interface, best digestion techniques for fragment isolation, and nanotoxicology.