• Journal of Korea Foundry Society
• /
• v.30 no.4
• /
• pp.147-150
• /
• 2010

An eco-friendly production technique of Al-8.6Ti-0.025C refiner was developed by melting a Al-Ti master alloy in a graphite crucible, in which the potential nucleation site, TiC effectively formed by the spontaneous in-situ reaction between excessive Ti and carbon from graphite crucible. The A3003 alloy refined by the Al-8.6Ti-0.025C showed effectively refined macrostructure and enhanced mechanical properties comparable to the commercial Al-Ti-B refiner. The effective refinement was achieved in a shorter compare to the melt-treating time commercial Al-Ti-B refiner.

• Development and Reproduction
• /
• v.7 no.2
• /
• pp.89-93
• /
• 2003

The present study observed the ultrastructure of testis of bluespotted mud hopper(Boleophthalmus pectinirostris), and sperrnatogenesis was discussed also. The testis was surrounded by a thin adventitia, inside which spermatocyst composed the parenchyma of testis. Each lobule was enwrapped by many spermatocysts, which were filled with different kinds of spermatogenic cell clusters at the same developmental stage. In the lobule lumen there are large numbers of spermatozoa The thin adventitia(outer wall) of testis was composed of outer epithelium, and the underlying layers, such as collagen fiber layer, and myoid tissue. The myoid tissue elongated into the inside of testis, became the main componentof interstitium between spermatocyst where sperrnatogenesis occurred. In addition interstitial cells containing dense homogeneous nucleus and abundant mitochondria were observed. Spermatogonia contained round nucleus with diffuse chromatin and nucleolus, and dense nuclear bodies surround by mitochondria in cytoplasm. The synaptonemal . complex was observed in primary spermatocytes clearly. Early spermatid presented larger round nucleus composed of granular chromatin, which was located in the center of cytoplasm. The nucleus of mid-spermatid composed of finely granular chromatin lied on one side of spermatid, and abundant mitochondria had migrated another side. A nuclear fossa appeared in the site near mitochondria in late-spermatid, and the centriole was formed in nuclear fossa.

• Applied Microscopy
• /
• v.40 no.2
• /
• pp.81-88
• /
• 2010

The fine structural characteristics of the apoptotic cells in the cutaneous epithelium of the anuran tadpole of the black-spotted frog, Rana nigromaculata was examined using the TUNEL (Terminal deoxynucleotidyl transferase-mediated biotinylated d-Uridine triphosphate Nick End Labeling) staining technique and TEM (transmission electron microscopy) observations. The cutaneous epithelium of the tadpole was composed of stratified cuboidal cells and the apoptotic cell death was observed continuously during the tail degeneration stages from the Shumway stage number 31 to 33. The early apoptotic cells shown in the epithelium demonstrated condensation and margination of the chromatin material at the nuclear periphery, and nuclear breakdown and cytoplasmic condensation were followed. Subsequent cytoplasmic degeneration of the apoptotic cell were produced by membrane-bounded cell fragments with relatively well preserved organelles. Following the processes of autophagic degradation, the late apoptotic cells being phagocytosed by other surrounding cells. These nearby cells, presumptive intraepithelial macrophages, contain a variety of lysosomal residual bodies which fuses with other cell organelles or other cytoplasmatic material to form secondary lysosomes. They are soon transformed into lamellar shaped vesicles and finally disappeared during the process of degradation.

• Applied Microscopy
• /
• v.34 no.2
• /
• pp.131-137
• /
• 2004

This study is observed the skin of the parrot fish, Oplegnathus fasciatus that related study of epidermal alternation with environmental and physiological change. It composed of supporting cells, unicellular glands and accessory cells. The supporting cells are classified into superficial cell, intermediated cell and basal cell. Superficial cell of epidermal layer is squamous or cuboidal and contain nucleus of ovoid type. And its free surface has many microridge which covered with glycocalyx. Intermediated cell is ovoid and has a nucleus of round shape. Basal cell is columnar, and nucleus is situated in the upper cytoplasm. Gland cells are classified into mucous cell and club cell. By the histochemical studies of the epidermal secretions the mucous materials react on blue in ABPAS (pH 2.5). Club cell is observed numerous vacuoles and microfilaments in the cytoplasm. The cytoplasm of chloride cells are occupied with numerous mitochondria. Pigment cells are classified into two type. The one contain pigment granules of electron dense, and the other contain reflecting platelets.

• Applied Microscopy
• /
• v.30 no.3
• /
• pp.273-283
• /
• 2000

To investigate the defensive effect of green tea against the lead toxicity, Sprague-Dewley rats (150 gm) were divided into 5 groups; the control group (A), the group treated with lead for 4 weeks (Group B-1), the group treated with lead and green tea for 4 weeks (Group B-2), the group treated with lead for 8 weeks (Group C-1), and the group treated with lead and green tea for 8 weeks (Group C-2). The lead acetate (500 ppm) was injected two times for one week into the abdomen and green tea solution (3 g/100 ml distilled water) offered freely. The results of histological and biocheical study are as follows; 1. Blood Urea Nitrogen (BUN) were increased in all the tested groups. The Group B-1 was more increased than the Group B-2, and the Group C-1 more than the Group C-2. The values of Alkaline phosphatase (ALP) were also decreased in all the tested groups, as such the former phenomenon. 2 In the Group B-1, some microvilli, mitochondria and rER were modificated on epithelial cell of proximal renal tubules. The cristae of mitochondria were enlarged, microvilli and nucleus were observed normally on the Group B-2. The number of Microvilli, mitochodria and rER were decreased, many lysosomes and irregular nucleus observed in the Group C-1. In the Group C-2, microvilli were modificated slightly and other organelles were observed similary with the Group B-2.

• The Korean Journal of Malacology
• /
• v.27 no.3
• /
• pp.213-221
• /
• 2011

Equilateral venus, Gomphina veneriformis exposed to tribultyltin chloride (TBTCl) for 36 weeks was showed ultrastructural changes of the mantle. The fine mantle had 4-folds and its epidermal layer consisted of simple columnar epithelial cells and ciliated cells and secretory cells. Inner and outer epidermal layer covered connective tissue. The mantle exposed to TBTCl at 12 weeks was decreased cilia in the inner epidermal layer, and observed extension of the hemolymph sinus and destruction of the septum. At 20 weeks, it revealed vacuole formation and pycnosis in the cytoplasm, and scattered muscular fiber. After 28 weeks of exposure, the mantle revealed partially degenerative changes in the epidermal layer. In the ciliated cells, basal body was isolated from the cilia and rootlet complex and basal foot were scattered. The sarcolemma had debris fiber. At 36 weeks, it observed degenerative cells that it revealed disappearance of the cilia, atrophic nucleus, poorly membrane and destruction of the cresternae in the mitochondria, and increasing heterophagosome. The outer epithelial cell had necrotic nuclus, numeous lysosome and disappearance of the microvilli. Therefore, results of this study suggested that chronical TBTCl exposure in the Gomphina veneriformis induced the disorders of shell growth and physiological function with histopathological changes of the mantle.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.05b
• /
• pp.371-372
• /
• 2003

서울의 지하철은 하루 450만 명 정도를 수송하는 중요한 대중교통 수단이다. 지하철 역사 내의 실내 환경에 대한 실내공기질 관리는 실내공기 오염의 대상물질에 대한 특정유해물질과 같은 단일 물질에 대한 지표에 의해 관리되고 있다. 그러나 공기중 입자상 물질의 특성은 복합적이기 때문에 공기질에 대한 관리는 여러 제한점을 가지고 있다. 또한 역구내의 먼지에 대한 단순 측정ㆍ분석만이 이뤄지고 있을 뿐 그 먼지의 생물학적 영향에 대한 연구는 미흡한 실정이다 본 연구에서는 지하철역 구내에서 포집한 미세먼지가 돌연변이원을 함유하고 있는 지를 여름과 겨울철에 대한 비교 평가하였다. (중략)

• The Korean Journal of Zoology
• /
• v.32 no.4
• /
• pp.351-357
• /
• 1989

To investigate the effect of alcohol on the ultrastructural changes of liver the experiment was undertaken by dividing in 3 groups (control, alcohol and alcohol-camitine groups). Chronic administration of ethanol to adult rats led to striking fat accumulation and ultrastructural changes in the liver. Mitochondrial abnormalities. dilation of endoplasmic reticulum, focal cytoplasmic degradation, dilation of bile canalicli and swelling of nucleus were observed. In alcohol-carnitine group, there were less fat accumulation and ultrastructural changes than alcohol group. These alterations suggest that ethanol is very toxic to the liver and carnitine prevents fat accumulation induced by alcohol. 알콜이 흰쥐 간장의 미세구조에 미치는 영향을 관찰하기위해 대조군, 알콜 처리군, 알콜-carnitine처리군으로 나누어 실험하였다. 만성적인 알콜 투여는 간에서의 지방축적을 유발하였으며 미토콘드리아의 이상, 소포체의 팽대, 세포질의 손상 Bile canaliculi의 확장 및 핵의 수축 등의 미세구조적 변화를 가져왔다. 알롤- carnitine으로 처리한 군에서는 지방의 축적과 미세구조의 변화가 알콜 처리군에서 보다는 약하였다. 이러한 구조적 변화는 알콜이 간에 매우유독하며 carnitine은 알콜에 의해 유발된 지방의 축적을 방지해 보여주는 것으로 사료된다.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.2
• /
• pp.148-152
• /
• 2000

To provide basic information on the integumentary system of the blenny, Pholis nebulosa, ultrastructures of epidermal and dermal layer were examined by means of the light and transmission electron microscope. The skin of the blenny consisted of epidermal and dermal layer. Epidermal layer consisted of supporting cell and unicellular gland. The supporting cells were classified into superficial cell, intermediated cell and basal cell, and the gland cells were classified into mucous secretory cell and club cell. The cytoplasm of supporting cells was divided into cortex and medullar part. In the cortex and medullar part, microfilaments and cell organelles were well developed, respectively. Superficial cell of epidermal layer was cuboidal and contained nucleus of horseshoe shape. Intermediated cell had a nucleus of irregular form and the electron density was higher than the other supporting cells, Basal cell was columnar, but nucleus was situated in the upper cytoplasm. Cell organelles of the basal cell were poor than the other supporting cells, but membrane interdigitations were well developed. The cytoplasm of mucous secretory cell had a well-developed ovoid secretory granules, which reacted to red with AB-PAS reaction. The club cell had a we31-developed round secretory granules and endoplasmic reticulum. figment cells were classified into two type. The one contained pigment granules of electron dense, and the other contained reflecting platelets. The cytoplasm of fibrocyte had n well developed rough endoplasmic reticulum.

• Development and Reproduction
• /
• v.2 no.2
• /
• pp.141-148
• /
• 1998

The fine structure of spermatozoa of Pungtungia herzi was examined with scanning and transmission electron microscopies. The spermatozoa of p. herzi are approximately 37.4 ${\mu}{\textrm}{m}$ in length and a relatively simple cell with a spherical nucleus, a short midpiece and a tail. The acrosome is not present as in most teleost fishes. The ultrastructure of spermatozoa represents typical characteristics of cyprinid spermatozoa including the lateral insertion of flagellum, the organization of centriolar complex in shallow nuclear fossa, and the occurrence and asymmetrical arrangement of mitochondria. In the nuclear envelope and mitochondrion, however there were some morphological differences for their ultrastructure. The nuclear envelope is severely undulated and the shallow nuclear fossa contains two centrioles which are at the angle of some 130$^{\circ}$ each other. The most significant feature can be observed with the mitochondrion; five or more mitochondria, which are shown in primary spermatocyte, fuse to form a single one in the mature spermatozoon. The mitochondrial aspect is different from that of other cyprinid spermatozoa, where their mitochondria have a conventional aspect and never fuse to form a mitochondrial derivative. In terms of sperm evolution the fused mitochondria are regarded as the apomorphic character in comparison with the separate mitochondria. The single mitochondrion is not reported in cyprinid spermatozoon except the case of Rhodeus.