• Applied Microscopy
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• v.29 no.2
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• pp.241-253
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• 1999

Fertilization pattern of north temperate bats is known to be unique for their sperm storage in the female reproductive tract during hibernation (e.g. Korean greater horseshoe bats). They copulate in fall but their ejaculated spermatozoa survive until the next spring. In another words they can persist to survive during long hibernation under the cold condition $(8\sim13^{\circ}C)$ and are to be fertilized with the ovum ovulated in the next spring, so called delayed fertilization. The present study was designed to observe morphological and functional changes of spermatozoa plasma membrane of the bats, hamsters which are hibernators, and mice which are non-hibernators in the room and the cold (bat-hibernation) temperatures and to confirm influence of the temperature on spermatozoa; survival rate, acrosome reaction rate, protein distribution, $Na^+-K^+-ATPase$ activities and scanning electron microscopic histochemistry. Based on the experimental results obtained in the present study, there were no significant morphological and functional differences in the spermatozoa plasma membrane in both the room and cold (bat-hibernation) temperatures and such an absence of difference suggests that the spermatozoa plasma membrane might play a pertinent role as a protector for consistent fertilization during and after hibernation.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.216-223
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• 2020

We investigated the morphology of the scalp hair shaft from the base to the distal end of the newborn hair and the ratio of the longitudinal axis diameter of the scale exposed to the surface of the hair to the diameter of the hair by scanning electron microscopy(SEM). Neonatal hair was observed to taper from the area adjacent to the scalp toward the end of the hair. In this study, as the thickness of the hair increases, the ratio of the long axis diameter of the exposed scale becomes relatively small, but the long axis diameter of the exposed scale on the surface of the hair is similar in length regardless of the thickness of the hair. In conclusion, it was confirmed that the major axis diameter of the scales exposed to the surface of fine or thick hair does not change significantly.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.1
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• pp.16-29
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• 1991

The occurrence of thrombotic occlusion & endothelial injuries at the site of anastomosis have been considered as major problems in microvascular surgery. The purpose of this study was to ascertain whether a end-in-end(sleeve, telescope) anastomosis compared favorably with end-to-end anastomosis in healing procedures on the endothelium and to study the possibility of clinical application in end-in-end method. The microvascular anastomoses have been performed with end-in-end method in the femoral arteries of 20 rats group, also with end-to-end method on the same arteries of another 20 rats group, and then the four anastomosed vessels in subdivided groups on each group were taken after period of 1, 3, 7, 14, 21 days following by anastomoses for scanning electron microscope observation. The results were as following: 1. The patency rate was 90% in the end-in-end group and 85%in the end-to-end group and late thrombus occurred at 7, 14 days on both groups, which suggested -consistent monitoring of patency was required for two weeks at least. 2. Platelet aggregates at the site of anastomosis began to organize on post-operation 3 days and in the end-in-end group, the initially decreased lumen of inserted vessel was gradually increasing on 7 days due to atrophy of the medial layers. 3. Re-endothelialization was completed between 7 and 14 days in end-in-end group, whereas between 14 and 21 days in end-to-end group.

• Journal of Plant Biology
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• v.37 no.2
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• pp.183-193
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• 1994

인삼(Panax ginseng C.A. Meyer)의 뇌두 캘러스로부터 분리한 원형질체와 배양된 원형질체의 미세구조 변화와 원형질막 표면을 투과 및 주사전자현미경으로 조사하였다. 분리 직후의 원형질체에서는 캘러스세포에서보다 작은 액포들이 많이 형성되어 있었다. 또한 활면소포체의 수가 증가하였으며 이들은 원형질막과 평행으로 배열하였다. 활면소포체는 가끔 세포질을 둘러싸서 세포질분리체(cytosegresome)를 형성하였고, 이 구조는 세포질을 분해시킨 후 액포로 변화하기도 하였다. 배양된 원형질체에서는 분리 직후의 원형질체와 비교하여 조면소포체, 딕티오좀, 리보좀, 미토콘드리아, proplastid 및 액포 등의 수가 현저하게 증가하였다. 딕티오좀으로부터 많은 소낭들이 형성되었고 이들은 세포질 전반에 걸쳐 존재하였다. 때로는 소낭들이 원형질막 바깥으로 돌출되어 돌기를 형성하기도 하였다. 배양된 원형질체의 표면에는 섬유소로 구성되어 있을 것으로 추정되는 섬유상 구조들이 형성되어 있었다.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.297-309
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• 2010

The objective of the present study was to perform a fracture analysis on fractured implant fixture after use in vivo and make clear the cause & mechanisms of failure. In case of fatigue fracture, the fractured surface represents fatigue striation. Fatigue striation indicate the progression of the crack front under cyclic loading, are characteristic of stage 2 crack growth. The site of crack initiation and stage 1 crack growth were not easily identified in any of the failure, presumably because of the complex microstructural features of the polycrystalline sample. In case of fractured by overload, dimpled or cleavage surface were observed. Using the interpretation of characteristic markings(ratchet mark, fatigue striation, dimple, cleavage et al) in fracture surfaces, failure events containing the crack origin, crack propagation, material deficiency could be understand.

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.252-257
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• 2019

We investigated the microstructure and morphological characteristics of microplastics added to rinse off cosmetics by scanning electron microscope. The size of the microplastic was in a wide range of sizes, from $250{\mu}m$ to 1.5mm in diameter. The small microplastics were in the shape of elongated particles and the large microplastics were cuboidal. Most cubic microplastics were observed in the form of squares or rectangles. The surface of the cubic microplastic was smoothly observed without protruding portions, but irregularly many gaps were formed. The gap between openings was measured from about $5{\mu}m$ to $20{\mu}m$. It has not been confirmed that these gaps are formed from the surface of the microplastic to the inside there of.

• Parasites, Hosts and Diseases
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• v.33 no.3
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• pp.231-234
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• 1995

Anisakid larvae were found from the liver and stomach of the codfish (Notothenia negzecta) caught from the Antarctic Ocean, South Pole, where the Polar Research Center of The Korea Ocean Research and Development Institute is operating- Through observations by scanning electron (SEM) and light microscopy (LM), they were identified as the third stage larvae of Pseunotewnnovo necipiens, a potential agent of human codworm anisakiasis. They measured 25.0-28.5 mm in length, and 0.6-0.8 mm in width. The SEM revealed a prominent boring tooth, three lips, and excretory pore at the anterior end, and a small but prominent mucron at the posterior end. From whole mounts and cross sections of the larvae the ventriculus, intestinal cecum and a Renette cell were found characteristically at the same plane. Raw eating of the codfish caught from the Antarctic Ocean near the South Pole should be avoided so as to prevent human codworm anisakiasis in this area.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.175-179
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• 1986

In order to develope a protoplast fusion of the genus Cellulomonas having high assimilibility of cellulose, the optimum conditions for the protoplast formation of Cellulomonas flavigena NCIB 12901 was investigated and observed by means of Scanning Electron Microscope. The results suggested that the susceptibility of the cell wall by lysozyme treatment on protoplast formation was considerably depend on the cultural periods of the cells. Cells of C. flavigena at mid exponential phase could more efficiently convert to protoplast cells than those at late exponential phase did. The rate of the protoplast formation was 95%, even though the rate was over 99.9% on counting by indirect method after osmotic shock treatment, when cells of the organism at mid exponential phase were treated with lysozyme (400$\mu\textrm{g}$/$m{\ell}$) for 6 hours and observed by SEM. In the evaluation of protoplast formation of the genus Cellulomonas, direct method of the observation under Scanning Electron Microscope was much more reliable than the counting method of protplasts after osmotic shock treatment. Because defferences between the number of spheroplast and protoplast were not able to be figured out on counting the number of protoplast after osmotic shock treatment.

• Applied Microscopy
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• v.33 no.2
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• pp.145-154
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• 2003

The present study was designed to demonstrate ionic zinc in the rat nasal mucosa by means of zinc selenium autometallography ($ZnSe^{AMG}$). Rats were given sodium selenide either intraperitoneally (i.p) or intranasally (i.n). Prior to the i.n. administration the rats were anesthetized with pentobarbital sodium (30 mg/kg, i.p.). A thin plastic tube coupled to a Hamilton syringe was then inserted into the right nostril and $10{\mu}l$ of the solution was instilled. For the i.p. administration non-anesthetized rats were given $100{\mu}l$ of the sodium selenide solution (10 mg/kg). Control rats were instilled with saline. After 2 hrs survival, the rats were anaesthetized and transcardially perfused with 3% glutaraldehyde. The olfactory area was removed and put into same fixative. The nose was then sectioned ($30{\mu}m$) horizontally, autometallography (AMG) was performed according to Danscher et al. (1997). After silver enhancement, fine AMG grains were scattered in the whole length of the olfactory epithelium containing olfactory receptor neurons, sustentacular and basal cells. However, much higher concentration of the AMG grains occupied near the surface and in the basal region of the olfactory epithelium. Both groups of i.p. and i.n. administration showed almost same level in the concentration of the AMG grains. In i.n. group, few AMG grains were also found in olfactory nerves of the lamina propria, suggesting zinc transport into the olfactory bulb via olfactory axons. At the electron microscopic level, the AMG grains were most entirely found in the supporting cells of the olfactory epithelium, and they were mostly localized in lysosome-like organelles. The i.n. group showed various signs of tissue damage of the olfactory mucosa, where dense concentration of AMG grains were localized at crystalloid structures. The present study demonstrated dense population of ionic zinc in the rat olfactory epithelium. zinc may play a role in the olfactory functioin and in the pathogenesis of the neurodegerative disorders affecting nose.

• The korean journal of orthodontics
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• v.18 no.2
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• pp.387-404
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• 1988

The purpose of this study was to investigate the root resorption and repair pattern of human teeth under intrusive orthodontic loadings of varying magnitude and duration. 50 gms, 100 gms, 200 gms of force applied to the 96 experimental teeth with duration of 2, 5, 7, 10 weeks, after removing the arch wire and retaining during 2 and 6 weeks, experimental teeth were extracted. Results were as follows: 1. The initial resorption site was visible in the apex within 2 weeks with 50 gms, 100 gms samples. 2. The sites of resorption increased markedly with duration of the force. 3. The 50 grams samples of the all duration reveal the shallow resorption and the 100 gms samples of the all duration except 2 weeks reveal the shallow and deep resorption sites. 4. After 7 weeks with 50 gms and 100 gms, cellular cementum repair accompanied the continuing resorption. 5. 2 and 6 weeks after removing the force with 200 gms, the same cellular cementum repair accompanied with 50 gms, 100 gms samples.