• Applied Microscopy
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• v.32 no.1
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• pp.17-30
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• 2002

The retinae of Todarodes pacificus and Octopus minor are divided into four layers that are an outer segment, a rod base region, an inner segment, and a plexiform layer, respectively. The retina of Octopus minor is about $20{\mu}m$ thicker ($400{\sim}420{\mu}m$) than that of Todarodes pacificus ($385{\sim}400{\mu}m$). A retina is composed of visual cells and supporting cells. The microvilli of length $0.6{\sim}0.7{\mu}m$ are packed densely on top of the supporting cells of Octopus minor while they are not found in Todarodes pacificus. The visual cells and supporting cells have pigment granules that exclude light. In case of Todarodes pacificus, the pigment granules of the visual cell are larger ($2.0{\times}0.5{\mu}m$) than those of the supporting cell ($1.0{\times}0.3{\mu}m$). But, the sizes of both cells are similar in Octopus minor. In the upper portion of a visual cell, microvilli shaped like a comb are forming a rhabdome (diameter, 60 nm) of a hexagonal structure. The rhabdome consists of 4 rhabdomere and the total area of a rhabdom of Octopus minor is larger than that of Todarodes pacificus. The synaptosome constructing a plexiform layer in Todarodes pacificus are divided into two types, each of which possess electron dense-core vesicles and electron lucent vesicles, respectively. Octopus minor also has two types of synaptosomes but each type comprises a mixture of electron dense vesicles and electron lucent vesicles, and electron lucent vesicles only, respectively, which is different from the case of Todarodes pacificus.

• Applied Microscopy
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• v.42 no.2
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• pp.61-66
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• 2012

Ultrastructural characteristics of blacktip grouper, Epinephelus fasciatus spermatozoa were investigated using transmission and scanning electron microscopy. The spermatozoa of E. fasciatus consisted of a spherical head part, a midpiece with cytoplasmic canal entrance and a flagellum with lateral fins. Internal ultrastructurally, the nucleus contains high electron dense chromatin having granular particles and has no acrosome. The centriolar complex lies outside of the nuclear fossa and it is connected by the osmophilic filaments. Also the osmophilic filaments connect between the centriolar complex and the nuclear membrane. The midpiece contains eight to nine spherical mitochondria, cytoplasmic canal and necklaces. The flagellum has a typical 9+2 axonemal structure. The lateral fins contain vesicles and a typical 9+2 axonemal structure. Consequently this study contributes to comparative grouper spermatology and provide useful systematic taxonomic characters.

• Parasites, Hosts and Diseases
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• v.33 no.3
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• pp.165-172
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• 1995

A transmission electron microscopic study was performed on the ultrastructure of the tegumental layer of GymophoLloines seoi (Digenea: Gymnophallidae) metacercarlae and adults. The metacercariae were obtained from naturally infected oysters, Crcssosoea gigas, and the adults from experimentally infected C3H mice. The tegumental layer generally revealed a small number of foldings, numerous small vacuoles, sines, and muscle bundles. Beneath the muscle layer, nuclei of the tegumental cells were located. There was little difference in the structure of the tegument between the metacercariae and adults. The oral sucker, having well-developed muscle layers, showed a similar structure to the ventral sucker except numerous foldlngs in the ventral sucker. The ventral pit was surrounded by a thin spcpiu layer, where a number of microtubules and mitochondria were seen. Around the ventral pit located well-developed circular and longitudinal muscles. The results showed that the ultrastructure of the tegumental layer of G. seoi metacercariae and adults revealed little difference from other trematodes in general. The ventral pit, a peculiar structure of this trematode, seems to function as a sphincter or an accessory adhesive organ.

• Journal of Chest Surgery
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• v.31 no.8
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• pp.739-748
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• 1998

Background: It has been well documented that transient occlusion of the coronary artery causes myocardial ischemia and finally cell death when ischemia is sustained for more than 20 minutes. Extensive studies have revealed that ischemic myocardium cannot recover without reperfusion by adequate restoration of blood flow, however, reperfusion can cause long-lasting cardiac dysfunction and aggravation of structural damage. The author therefore attempted to examine the effect of postischemic reperfusion on myocardial ultrastructure and to determine the rationales for recanalization therapy to salvage ischemic myocardium. Materials and methods: Young Holstein-Friesian cows(130∼140 Kg body weight; n=40) of both sexes, maintained with nutritionally balanced diet and under constant conditions, were used. The left anterior descending coronary artery(LAD) was occluded by ligation with 4-0 silk snare for 20 minutes and recanalized by release of the ligation under continuous intravenous drip anesthesia with sodium pentobarbital(0.15 mg/Kg/min). Drill biopsies of the risk area (antero-lateral wall) were performed at just on reperfusion(5 minutes), 1-, 2-, 3-, 6-, 12-hours after recanalization, and at 1-hour assist(only with mechanical respiration and fluid replacement) after 12-hour recanalization. The materials were subdivided into subepicardial and subendocardial tissues. Tissue samples were examined with a transmission electron microscope (Philips EM 300) at the accelerating voltage of 60 KeV. Results: After a 20-minute ligation of the LAD, myocytes showed slight to moderate degree of ultrastructural changes including subsarcolemmal bleb formation, loss of nuclear matrix, clumping of chromatin and margination, mitochondrial destruction, and contracture of sarcomeres. However, microvascular structures were relatively well preserved. After 1-hour reperfusion, nuclear and mitochondrial matrices reappeared and intravascular plugging by polymorphonuclear leukocytes or platelets was observed. However, nucleoli and intramitochondrial granules reappeared within 3 hours of reperfusion and a large number of myocytes were recovered progressively within 6 hours of reperfusion. Recovery was apparent in the subepicardial myocytes and there were no distinct changes in the ultrastructure except narrowed lumen of the microvessels in the later period of reperfusion. Conclusions: It is likely that the ischemic myocardium could not be salvaged without adequate restoration of coronary flow and that the microvasculature is more resistant to reversible period of ischemia than subendocardium and subepicardium. Therefore, thrombolysis and/or angioplasty may be a rational method of therapy for coronarogenic myocardial ischemia. However, it may take a relatively longer period of time to recover from ischemic insult and reperfusion injury should be considered.

• Applied Microscopy
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• v.37 no.1
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• pp.23-33
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• 2007

The lacrimal gland are compound tubule-acinar glands. The main lacrimal function is the production of the aqueous layer, the thickest and major constituent of the precorneal tear film. The lacrimal gland also has an important function in the defense system of the ocular surface, forming a part of the conjunctival-associated hymphoid tissue. The ultrastructural characteristics of the lacrimal gland of the rabbit were described. The lacrimal tissues of rabbits were processed through the conventional techniques for transmission electron microscopy. The secretory portions consisted of three cell types: 1. Serous cells with electron dense secretory granules. 2. Seromucous cells containing variable moderately electron dense secretory granules with flocculent material. 3. Mucous rolls containing mucous secretory granules. The serous cells were situated at the basal portion of acini, and they contained electron dense granules of variable densities and sizes. The seromucous cells contained a few protein secretory granules and more mucous secretory granules. The mucous cells contained even fewer protein secretory granules and exclusively mucous secretory granules. The epithelium of the intralobular ducts showed secretory granules, junctional complexes, and large basolateral intercellular spaces with lateral folds. These study might be helpful in determining inter-relationships, similarities and differences among the orbital glands of various physiological or pathological conditions.

• The Journal of the Petrological Society of Korea
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• v.22 no.3
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• pp.219-233
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• 2013

Spherulitic rhyolite occur as part of ring dyke which showing a vertical flowage of $60^{\circ}{\sim}90^{\circ}$, of the Jangsan cauldron was studied. The spherulites range in diameter from a few millimeters to 2.8 centimeters or more, and average 5~10 millimeters. It belongs to radiated simple spherulite type. They consist of a core of moderate brown dense material encased by a thin crust, a few millimeters thick at most of white grey material. The spherulites frequently have a radiating fibrous structure, which are thought to have formed as a consequence of rapid mineral growth caused by very fast cooling of the dykes in shallow depth near the surface. EPMA examination of the concentric-zoned core of spherulites show that they are mainly composed of cryptocrystalline-fibrous intergrowth of silica minerals and alkali feldspars which have $SiO_2$ 82% or more, $Al_2O_3$ 7~10%, $Na_2O+K_2O$ less than 8%. The feldspar compositions of the spherulites lie essentially within the sanidine field. XRD examination show that spherulites are mainly composed of quartz, sanidine, albite with minor mica, kaolinite and chlorite. According to X-ray mapping, the spherulites are enriched in $SiO_2$ in the core and partly enriched $Na_2O$ or $K_2O$, $Al_2O_3$ in the shell that reflect in compositional zoning with increasing spherulitic devitrification. The feathery and non-equant crystal shapes of spherulites from rhyolite dyke of Jangsan cauldron suggest that they may have formed during the rapid cooling of dyke under the static state, or faster velocity of devitrification from glassy materials than movement velocity of the magma intrusion. The spherulitic rhyolite originated from high-silica(75.4~75.7 wt.%) rhyolite magma.

• The Journal of the Petrological Society of Korea
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• v.28 no.3
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• pp.171-193
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• 2019

This study aims to identify the geometry and internal structures of the Yeongdeok Fault, a branch fault of the Yangsan Fault, by detailed mapping and to characterize its kinematics by analyzing the attitudes of sedimentary rocks adjacent to the fault, slip data on the fault surfaces, and anisotropy of magnetic susceptibility (AMS) of the fault gouges. The Yeongdeok Fault, which shows a total extension of 40 km on the digital elevation map, cuts the Triassic Yeongdeok Granite and the Cretaceous sedimentary and volcanic rocks with about 8.1 km of dextral strike-slip offset. The NNW- or N-S-striking Yeongdeok Fault runs as a single fault north of Hwacheon-ri, Yeongdeok-eup, but south of Hwacheon-ri it branches into two faults. The western one of these two faults shows a zigzag-shaped extension consisting of a series of NNE- to NE- and NNW-striking segments, while the eastern one is extended south-southeastward and then merged with the Yangsan Fault in Gangu-myeon, Yeongdeok-gun. The Yeongdeok Fault dips eastward with an angle of > $65^{\circ}$ at most outcrops and shows its fault cores and damage zones of 2~15 m and of up to 180 m wide, respectively. The fault cores derived from several different wall rocks, such as granites and sedimentary and volcanic rocks, show different deformation patterns. The fault cores derived from granites consist mainly of fault breccias with gouge zones less than 10 cm thick, in which shear deformation is concentrated. While the fault cores derived from sedimentary rocks consist of gouges and breccia zones, which anastomose and link up each other with greater widths than those derived from granites. The attitudes of sedimentary rocks adjacent to the fault become tilted at a high angle similar to that of the fault. The fault slip data and AMS of the fault gouges indicate two main events of the Yeongdeok Fault, (1) sinistral strike-slip under NW-SE compression and then (2) dextral strike-slip under NE-SW compression, and shows the overwhelming deformation feature recorded by the later dextral strike-slip. Comparing the deformation history and features of the Yeongdeok Fault in the study area with those of the Yangsan Fault of previous studies, it is interpreted that the two faults experienced the same sinistral and dextral strike-slip movements under the late Cretaceous NW-SE compression and the Paleogene NE-SW compression, respectively, despite the slight difference in strike of the two faults.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.3
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• pp.115-121
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• 2008

Microstructure of glass-ceramics obtained by heat treating silicate glass containing 50 wt% electric arc furnace dust (EAF dust) and nucleation agents were observed. The crystallization temperature, $T_c$ of glassy specimen measured around $850^{\circ}C$ from different thermal analysis, so the heat treatment condition to obtain glass-ceramic specimen was selected as $950^{\circ}C/15 hr$. The nucleation agent, $TiO_2$ showed the superior effect on enhancing franklinite crystal growth which has stronger mechanical properties and more durable chemical resistance than willemite phase. Some specimens containing $TiO_2$ had the augite crystal phase and increasing $TiO_2$ amount decreased a fraction of willemite and increased a franklinite. Especially, the specimen with 5 wt% $TiO_2$ showed no willemite crystal phase and $1{\sim}2\;{\mu}m$ franklinite crystals dispersed uniformly in glassy matrix. Also, the specimens containing 5 wt% $TiO_2$ mixed with $Fe_2O_3$ showed a dendrite-shaped franklinite crystals caused by coalescence of small crystallites.

• Journal of Life Science
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• v.18 no.2
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• pp.200-205
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• 2008

The purpose of this study is to investigate the effects of the herbal Chokong pill (hereafter HCKP) on the liver cell and enzyme activities of serum in rat. HCKP were mixed with pickled black soybeans and five different kinds of medicinal herbs (Rhynchosia nulubilis, Glycyrrhiza uralensis, Zizyphus vulgaris, Atractylodes macrocephala K., Astragalus membranaceus and Cornus officinalis). Four groups of male Sprague-Dawley rats were fed by different diets for 9 weeks: normal diet (Nor), high-fat diet (HF), high-fat diet supplemented with 1% (T1) and 5% (T5) HCKP powder, respectively. Depending on the presence of HCKP in high fat diet, the activities of the blood serum GOT and GPT were decreased. GOT and GPT activities of T1 and T5 were decreased 6.1%, 17.8% and 25.4%, 32.4% compared with HF. On microstructure observing through the transmission electron microscope (TEM) of liver cell, in normal group, a normal large and clear nucleus, rough endoplasmic reticulum (RER) and mitochondria possessing well-defined double outer-limiting membranes were found. However, in HF, it was hard to observe the microstructures in cytoplasm, because of too many fat granules. It showed severely damaged cell, pyknotic nucleus, swollen disintegrating RER and mitochontria loosing the cristae. In T1, there were more repaired liver cells and less fat granules than HF. In T5, there were much less numbers and smaller size of the fat granules than T1, and the morphology was similar to normal cell.

• Journal of Oral Medicine and Pain
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• v.26 no.3
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• pp.205-214
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• 2001

오늘날 스트레스라는 단어는 모든 현대인과 방송, 언론매체에서도 매일 거론되어질 정도로그 중요성이 대두되고 있다. 의학계에서도 스트레스를 단순한 심리적 문제로 국한시키지 않고 과도한 스트레스가 지속될 경우 신경계와 내분비계, 면역계의 변화를 초래해 인체의 항상성에 영향을 미쳐 질병을 일으킨다는 것을 인식하고 있으며 이에 대한 연구가 진행되고 있다. 이러한 질병의 발생과정에서 생체의 일부조직이 파괴됨으로써 기능과 형태변화가 초래될 때 apoptosis가 관여하고 있으며 이에 본 저자는 스트레스와 구강악안면영역에서 발생할 수 있는 질병과의 상관관계를 규명하기 위해 이종의 한냉 스트레스와 다소의 굴신을 허용한 중등도의 구속 스트레스를 부여한 후 측두하악관절 활막의 변화를 전자현미경관찰을 통해 밝혀내고자 한다. Sprague-Dawley계 웅성 백서(200-230 g/bw) 33마리를 구속스트레스부여군 (12마리), 한냉스트레스부여군 (12마리) 및 정상군 (3마리)으로 나누고 이들을 각각 구속장치에 구속한 후 1, 3, 5, 7일에 각각 희생시켰으며 측두하악관절 활막의 변화를 전자현미경으로 관찰하였다. 그 결과는 다음과 같다. 1. 중등도의 구속스트레스군에서 사립체는 부분적으로 농축된 소견을 보였으며 수와 크기에 있어 시간이 지남에 따라 점차 감소하는 소견을 보였다. 2. 중등도의 구속스트레스군에서 과립내형질망은 점점 확장되었으며 불규칙한 형태를 나타내었다. 3. 중등도의 구속스트레스군에서 물결모양의 핵막의 이중구조가 7일군에서 관찰되었다. 4. 한냉 스트레스군에서 사립체는 1일, 3일군에서 약간 부푼 형태를 가지고 그 수가 다소 감소되었으나 시간이 지남에 따라 5일, 7일군에서 건강한 모양으로 점차 증가되었다. 5. 한냉 스트레스군에서 과립내형질망은 1일, 3일군에서 불규칙하게 확장된 소견을 보였으나 5일, 7일군에서는 잘 발달된 형태로 핵 주위에서 다수 관찰되었다. 6. 한냉 스트레스군에서 핵은 전 기간에 걸쳐 큰 변화를 보이지 않았다. 이와 같은 결과를 토대로 측두하악관절 활막조직은 한냉 스트레스 및 중등도의 구속 스트레스에 대하여 중등도의 저항성을 가지고 있는 것으로 생각되며 생리적 적응한계를 넘는 과도하고 지속적인 스트레스에 의하여 활막조직이 apoptosis되어 측두하악관절에 병리적 변화를 초래할 가능성이 있다고 사료되어 이후 지속적인 연구가 요구된다.