• Journal of fish pathology
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• v.29 no.1
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• pp.7-12
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• 2016

In a previous study on the parasites of cultured rock bream (Oplegnathus fasciatus), we reported the discovery of a new species, Ceratomyxa oplegnathus, obtained from the gallbladder. In the present study, we found another Ceratomyxa species, C. sparusaurati, also from the gallbladder of rock bream. The morphological and ultrastructural characteristics of C. sparusaurati were investigated using light and transmission electron microscopy (TEM).

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.137.1-137.1
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• 2008

• Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.32-35
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• 2002

In this study, we investigated the mechanism of cell death in rhabdovirus-infected cells, chinook salmon embryonic cell line (CHSE-2l4) infected with hirame rhabdovirus (HIRRV). Studies using light microscopy, fluorescence microscopy, TUNEL method, electron microscopy, and agarose gel electrophoresis revealed changes in the cell morphology and DNA fragmentation indicative of apoptosis in early infection. It was observed that HIRRV induced apoptosis as well as necrosis in infected cells.

• Applied Microscopy
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• v.28 no.3
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• pp.263-271
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• 1998

Oocyte maturation of the swordtail (Kiphophorus hellerii) was investigated by light and electron microscopy. In the ovary of the swordtail, various staged oocytes were observed, Mature oocytes were located in ovarian cortex, meanwhile immature ones were positioned in ovarian medulla. The oocyte was surrounded by several structures or cells such as chorion, follicle cells, follicular theaca and ovarian epithelium, respectively, from the inside toward outside. Growing and maturing oocytes healed numerous microvilli which interconnected the oocyte and the follicle cells to communicate each other. The mature oocyte had the electron dense chorion which appeared to be ultrastructure of two layers and contained pore canals. Oocyte maturation was characterized by not only the enlarged cell size and well differentiated cell organelles, brit also the increases of fat droplets, pinocytotic vesicles and yolk granules.

• Applied Microscopy
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• v.28 no.3
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• pp.283-297
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• 1998

Hemopoiesis and morphogenesis of the human fetal liver through from 10 to 32 weeks of gestation were investigated by light and electron microscopy. The results obtained were as follows. Hemopoiesis of fetal liver tissue was found from 10 to 32 weeks of gestation, but the hemopoiesis was decreased at 32 weeks of gestation. At the 32 weeks of gestation, matured erythrocytes were observed in the sinusoid, and formation of liver cell cord and portal triad were established. Differentiation of hepatic cell was characterized by the increase of amount of cell organelles within cytoplasm, decrease of hemopoietic cell, morphological change of nuclear envelope from folding form to round form during the developmental period. These results suggest that human fetal liver plays a hematopoietic function until bone marrow and spleen play their function, but morphology of liver at 32 weeks of gestation was differed with structure observed in liver of adult.

• Applied Microscopy
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• v.26 no.4
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• pp.421-430
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• 1996

The endocrine cells in the midgut epithelium of the Japanese cockroach, Periplaneta japonica were observed by the light and electron microscopy. The midgut epithelium of the last instar larva and adult cockroach consisted of principal columnar cells, regenerative cells, and secretory granular cells. Midgut endocrine cells were positioned basally as a cone-shaped single cell in the epithelium or underneath the regenerative crypt cells. When midgut epithelium grows and the cell composing it transforms, between the endocrine cells and regenerative cells were made desmosome type junction and large vesicular shaped stretches of loose contact. The endocrine cells were characterized by a clear cytoplasm with abundant Golgi complex and numerous secretory granules. The secretory granules in the cell were spherical and electron dense with their diameter of $200{\sim}400nm$. The secretory granules have been observed as discharged by exocytosis on the basal and lateral side of the cell.

• Journal of the Optical Society of Korea
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• v.15 no.1
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• pp.9-14
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• 2011

In this study, the internal structure of an optical waveguide embedded in a flexible optical circuit board is observed with a confocal microscope. In order to increase the light reflection from an internal material interface with a very small index difference, and thus enhance the signal contrast, a theta microscopy scheme has been integrated into a conventional confocal microscope, and a high NA oil-immersion lens has been used. The interface reflectivity is increased from roughly 0.0015% to 0.025% by the proposed method, and the internal structure can thus be successfully measured.

• Current Optics and Photonics
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• v.2 no.2
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• pp.172-178
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• 2018

We propose a precise 3D endoscopic technique for medical and industrial applications. As the 3D measuring principle, the continuously scanning structured illumination microscopy (CSSIM), which enables to obtain 3D sectional images by the synchronous axial scanning of the target with the lateral scanning of the sinusoidal pattern, is adopted. In order to reduce the size of the probe end, the illumination and detection paths of light are designed as coaxial and a coherent imaging fiber bundle is used for transferring the illumination pattern to the target and vice versa. We constructed and experimentally verified the proposed system with a gauge block specimen. As the result, it was confirmed that the 3D surface profile was successfully measured with $16.1{\mu}m$ repeatability for a gauge block specimen. In order to improve the contrast of the sinusoidal illumination pattern reflected off on the target, we used polarizing optical components and confirmed that the visibility of the pattern was suitable in CSSIM.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.435-444
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• 2021

The genus Chroomonas is a group of blue-green colored cryptomonads. This study describes two freshwater Chroomonas species for the first time in South Korea: Chroomonas nordstedtii Hansgirg and Chroomonas coerulea (Geitler) Skuja. We examined the morphology and ultrastructure of these species by light microscopy, scanning electron microscopy, and transmission electron microscopy. These two Chroomonas species were blue-green colored and ovate to oval-shaped. Chroomonas nordstedtii was characterized by two Maupas ovals with hexagonal periplast plates, whereas C. coerulea was characterized by one eyespot with rectangular periplast plates. A molecular phylogeny with data from nuclear SSU rRNA and chloroplast rbcL genes revealed that Korean C. nordstedtii formed a distinct clade with NIES-708, NIES-1004 from Japan, and UTEX 2779 from Colorado, USA, while C. coerulea formed a clade with ACOI 1366 from Portugal.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.326-331
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• 2023

The utilization of scanning transmission electron microscopy (STEM) in conjunction with cathodoluminescence (CL) has emerged as a valuable tool for the investigation of material optical properties. In recent years, this technique has facilitated significant advancements in the fields of plasmonics and quantum emitters by surpassing prior technical restrictions. The review commences by providing an outline of the diverse STEM-CL operating modes and technical aspects of the instrumentation. The review explains the fundamental physics of light production under electron beam irradiation and the physical basis for interpreting STEM-CL experiments for different types of excitations. Additionally, the review compares STEM-CL to other related techniques such as scanning electron microscope CL, photoluminescence, and electron energy-loss spectroscopy.