Applied Microscopy最新文献

The purple spaghetti-eel Moringua raitaborua lives on the sandy or muddy bottoms of estuaries, which are subject to rapid and wide changes in salinity, pH, and osmoregulatory and hypoxic conditions due to the influx of organic materials from sources of freshwater. The species has adapted to hypoxic environments by developing a thicker epidermis with stratified polygonal cells, club cells, two types of mucous cells (goblet and, oval cells), stratified cuboidal cells and dermis with abundant blood capillaries. Among them, histological modification of thinner dorsal, lateral, and ventral body skin to include abundant capillaries and well-developed dermal vascularization may provide cutaneous respiration, permitting survival in brackish waters with low levels of oxygen and variable environmental parameters.

The structural analysis of nanocrystals via transmission electron microscopy (TEM) is a valuable technique for the material science field. Recently, two-dimensional images by scanning TEM (STEM) and energy-dispersive X-ray spectroscopy (EDS) have successfully extended to three-dimensional (3D) imaging by tomography. However, despite improving TEM instruments and measurement techniques, detector shadowing, the missing-wedge problem, X-ray absorption effects, etc., significant challenges still remain; therefore, the various required corrections should be considered and applied when performing quantitative tomography. Nonetheless, this 3D reconstruction technique can facilitate active site analysis and the development of nanocatalyst systems, such as water electrolysis and fuel cell. Herein, we present a 3D reconstruction technique to obtain tomograms of IrNi rhombic dodecahedral nanoframes (IrNi-RFs) from STEM and EDS images by applying simultaneous iterative reconstruction technique and total variation minimization algorithms. From characterizing the morphology and spatial chemical composition of the Ir and Ni atoms in the nanoframes, we were able to infer the origin of the physical and catalytic durability of IrNi-RFs. Also, by calculating the surface area and volume of the 3D reconstructed model, we were able to quantify the Ir-to-Ni composition ratio and compare it to the EDS measurement result.

In the evaluation of human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) — one of the standard biomarkers for breast cancer— visual assessment is laborious and subjective. Image analysis using whole slide image (WSI) could produce more consistent results; however, color variability in WSIs due to the choice of stain and scanning processes may impact image analysis. We therefore developed a calibration protocol to diminish the staining and scanning variations of WSI using two calibrator slides. The IHC calibrator slide (IHC-CS) contains peptide-coated microbeads with different concentrations. The color distribution obtained from the WSI of stained IHC-CS reflects the staining process and scanner characteristics. A color chart slide (CCS) is also useful for calibrating the color variation due to the scanner. The results of the automated HER2 assessment were compared to confirm the effectiveness of two calibration slides. The IHC-CS and HER2 breast cancer cases were stained on different days. All stained slides and CCS were digitized by two different WSI scanners. Results revealed 100% concordance between automated evaluation and the pathologist’s assessment with both the scanner and staining calibration. The proposed method may enable consistent evaluation of HER2.

This study investigated the anti-obesity effects of yuja pomace extract fermented with lactic acid bacteria in rats with high-fat diet-induced obesity over a period of eight weeks. Epididymal fat cell size was significantly smaller, by about 33%, in the treatment groups given yuja pomace extract fermented with lactic acid bacteria compared to the CON group. Electron microscopic observation of hepatocyte microstructure showed that the number of lipid droplets was lower in hepatocytes, the number of mitochondria was higher, along with distinct cristae, and the rough endoplasmic reticula were well developed with stacks of cisternae and ribosomes. Thus, it is believed that yuja pomace extract fermented with lactic acid bacteria, by influencing body weight and lipid accumulation, is effective in the prevention and treatment of obesity.

The eggs laid by the orb web spider Trichonephila clavata must overwinter in bitterly freezing and dry conditions before hatching, but there does not seem to be any protection like a compact silk case covering the entire eggmass. Instead, the surface of the eggmass is completely coated with a milky coating called chorionic microspheres (CM). Therefore, we investigated the fine structural characteristics of CM to demonstrate their ecological importance. Although the diameter of CM in outer eggmass exhibits a significant variation, the chorionic surface is coated with a single layer of CM, characterized by a consistent diameter of approximately 2.3 µm. The surface structure of aggregated CM shows short papillary projections demonstrating segmental adhesion of mucous components. CM is insoluble in water but partially soluble in anhydrous ethanol, and its spherical structure is completely decomposed by hexafluoroisopropanol (HFIP), a strong organic solvent. Since our fine structural observations clearly show that CM is not derived from vitellogenic or choriogenetic processes, the CM adhesive coatings during ovipositional process appears to be equivalent to cocoon silk for various protective functions in silken eggcase.

Grain boundaries (GBs) are one- or two-dimensional (2D) defects, which are universal in crystals and play a crucial role in determining their mechanical, electrical, optical, and thermoelectric properties. In general, GBs tend to decrease electrical or thermal conductivity, and consequently degrade the performance of devices. However, the unusual characteristics of GBs have led to the production of a new class of memristors with 2D semiconducting transition metal dichalcogenides (TMDs) and the creation of conducting channels in 2D topological insulators. Therefore, understanding the nature of GBs and their influence on device applications emphasizes the importance of GB engineering for future 2D TMD-based devices. This review discusses recent progress made in the investigation of various roles of GBs in 2D TMDs characterized via scanning tunneling microscopy/spectroscopy.

Diabetes mellitus (DM) is a metabolic disease that affects all systems in the body, including the liver. Numerous studies have reported that chronic DM etiology and pathogenesis complications implicate oxidative stress, generating reactive oxygen species, such as superoxide anions and free radicals. In addition, pro-inflammatory reactions are also underlying functions closely related to oxidative stress that further exacerbate pathological DM states. The liver is especially susceptible to hyperglycemia-induced oxidative stress and the related inflammation. Thus, anti-oxidation and anti-inflammation therapies are promising strategies for treating liver damage. This review summarizes therapeutic treatments attenuating the generation of oxidative stress and pro-inflammation, which also cause DM-induced liver injury. Although the treatments have several impediments to be solved, these remedies may have clinically important implications under the absence of effective drugs for the damaged liver in DM patients.

The Gonggeom-ji reservoir is an agricultural one built for rice farming during the Proto-Three Kingdoms period and was designated as Gyeongsangbuk-do monument No. 121 because of its high historical value. The Nakdonggang National Institute of Biological Resources has been conducting paleontological and paleoenvironmental studies on major wetlands from Korea since 2016, as well as diatom, geological, and depth distribution analyses on the sedimentary soil of Gonggeom-ji. This study summarized the description and ecological characteristics of six newly recorded diatoms (Gomphonema lacusrankala, Pinnularia diandae, P. gibba var. hyaline, P. lacunarum, Sellaphora labda var. nipponica, Stauroneis angustilancea) found in samples collected through drilling in Gonggeom-ji in 2019.

Globally, cyanobacteria frequently cause blooms that outcompete other species in the waterbody, affecting the diversity, decreasing water exchange rates, and promoting eutrophication that leads to excessive algal growth. Here, Dolichospermum circinale (akinetes) and Microcystic aeruginosa (resting cells), were isolated from the sediment in the Uiam Dam in the North Han River and near Ugok Bridge in the Nakdong River, respectively. The morphology, germination process and rates, and growth was evaluated in different environmental conditions. D. cercinalis germination began on day two of culturing, with maximum cell growth observed on day ten. In contrast, M. aeruginosa exhibited daily increase in cell density and colony size, with notable density increase on day six. Next, different environmental conditions were assessed. Akinetes exhibited high germination rates at low light intensity (5—30 µmol/m²/s), whereas resting cells exhibited high growth rates at high light intensity (50—100 µmol/m²/s). Furthermore, both cell types exhibited optimum germination and growth in media containing N and P at 20—30° at a pH of 7—9. Our study reveals the optimum conditions for the germination and growth of cyanobacterial akinetes and resting cells isolated from river sediment, respectively, and will assist in predicting cyanobacterial blooms for appropriate management.

Oxidative stress destroys cellular organelles and damages DNA, eventually leading to degenerative brain disorders. Persistent mitochondrial damage by oxidative stress eventually causes cells to inhibit the function of lysosomes. Rotenone used in this study inhibits complex 1 of the mitochondrial electron transport chain. Due to this inhibition, the production of free radicals is promoted, and oxidative stress can occur. To test as a role of antioxidant, L-serine was treated before treatment of rotenone to HT22 hippocampal cells. Then, changes in the activity and structure of lysosomes were analyzed. As a result, the oxidative stress caused by rotenone in HT22 cells was protected by L-serine. L-serine reduced free radicals in cells, and the damaged lysosomal structure and lysosome activity were also protected.