• Journal of the Korean Wood Science and Technology
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• v.34 no.2
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• pp.68-77
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• 2006

The heartwood of cengal (Neobalanocarpus heimii) is known to have a high degree of decay resistance by virtue of its high extractive content. After 30 years in ground contact an utility pole of this tropical hardwood was found to be degraded only in the surface layers by cavity-forming soft rot fungi. The present work was undertaken 1) to characterize the degradation of cengal heartwood from the aspect of ultrastructure and chemistry and 2) to investigate the correlation between soft rot decay and its extractive microdistribution in wood tissues. The chemical analysis of cengal heartwood revealed the presence of a high amount of extractives as well as lignin. The wood contained a relatively high amount of condensed lignin and the guaiacyl units. Microscopic observations revealed that vessels, fibers and parenchyma cells (both ray and axial parenchyma) all contained extractives in their lumina, but in variable amounts. The lumina of fibers and most axial parenchyma were completely or almost completely filled with the extractives. TEM micrographs showed that cell walls were also impregnated with extractives and that pit membranes connecting parenchyma cells were well coated and impregnated with extractives. However, fungal hyphae were present in the extractive masses localized in cell lumina, and indications were that the extractives did not completely inhibit fungal growth. The extent of cell wall degradation varied with tissue types. The fibers appeared to be more susceptible to decay than vessels and parenchyma. Middle lamella was the only cell wall region which remained intact in all cell types which were severely degraded. The microscopic observations suggested a close correlation between extractive microdistribution and the pattern and extent of cell wall degradation. In addition to the toxicity to fungi, the physical constraint of the extractive material present in cengal heartwood cells is likely to have a profound effect on the growth and path of invasion of colonizing fungi, thus conferring protection to wood by restricting fungal entry into cell walls. The presence of relatively high amount of condensed lignin is also likely to be a factor in the resistance of cengal heartwood to soft rot decay.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.693-703
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• 2003

The present study evaluated the effects of guided tissue regeneration using xenograft material(deproteinated bovine bone powder), with and without Calcium sulfate membrane in beagle dogs. Contralateral fenestration defects (6 ${\times}$ 4 mm) were created 4 mm apical to the buccal alveolar crest of maxillary premolar teeth in 5 beagle dogs. Deproteinated bovine bone powders were implanted into fenestration defect and one randomly covered Calcium sulfate membrane (experimental group). Calcium sulfate membrane was used to provide GTR. Tissue blocks including defects with soft tissues which were harvested following four & eight weeks healing interval, prepared for histo-phathologic analysis. The results of this study were as follows, 1. In control group, at 4 weeks after surgery, new bony trabecular contacted with interstitial tissue and osteocytes lie cell were arranged in new bony trabecule. Bony lamellation was not observed. 2. In control group , at 8 weeks after surgery, scar-like interstitial tissue was filled defect and bony trabecule form lamellation. New bony trabecular was contacted with interstitial tissue but defect was not filled yet. 3. In experimental group, at 4 weeks after surgery, new bony trabecular partially recovered around damaged bone. But new bony trabecule was observed as irregularity and lower density. 4. In experimental group, at 8 weeks after surgery, lamella bone trabecular developed around bone cavity and damaged tissue was replaced with dense interstitial tissue. In conclusion, new bone formation regenerated more in experimental than control groups and there was seen observe more regular bony trabecular in experimental than control groups at 4 weeks after surgery. In control group, at 8 weeks after surgery, the defects was filled with scar-like interstitial tissue but, in experimental group, the defects was connected with new bone. Therefore xenograft material had osteoconduction but could not fill the defects. We thought that the effective regeneration of periodontal tissue, could be achieved using GTR with Calcium sulfate membrane.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.409-417
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• 2010

Present study aimed to investigate morphological and physiological change in the tissues of Carassius auratus after exposure against Pb (lead) with various rearing condition. We measured the level of accumulated heavy metal and analyzed ultrastructure with transmission electron microscopy. The heavy metal, Pb, was accumulated in the gill, bone and integument increased drastically for exposure periods, the 40 days. The accumulation of Pb in the gill showed relatively higher than that in other tissues. And accumulated Pb amounts also were increased with exposure time dependent manner in the gill, bone and integument tissues. Also, specific activities of antioxidation enzymes in all tissue after exposure to Pb were increased in the course of exposure. And the activities of SOD from tissues exposed to Pb were increased 2 folds than those from the unexposed but GPX activities were maintained constant. The increased numbers of mucous cells in gill tissues exposed to Pb were determined and morphological changes, such as clubbing and fusion, were shown secondary lamella. Also, exposure of Pb for 40 days on gills tissues cause membrane damage in mitochondria and nucleus. In kidney tissues, the atrophied glomerulus was observed, and the empty space in Bowman's capsule was expanded. Based on the all results, it is suggested that the exposure to the high level of Pb for long period affect on the morphology of tissues, and change the enzymatic balance in C. auratus.

• Journal of Sericultural and Entomological Science
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• v.27 no.1
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• pp.1-11
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• 1985

In order to clarify the taxanomic position of a new microsporidia K79 which was isolated from the silkworm larvae, Bombyx mori L. in Korea in 1979, the following several experiments such as estimation of pathogenicity in different instar, histopathological examination under light and electronic microscope and examination of fine structure of the sporse were carried out and their result obtained are as follows. In the test of pathogenicity by oral inoculation, the new microsporidia K79 was lower than Nosema bombycis and the susceptibility of the new microsporidia to silkworm was getting lower as the silkworm larvae grew. The lesion of Silkworms' tissue which was infected with the new microsporidia K79 was found in the epithelial cells of trachea, fat body and silk gland cells. The developmental process of the new microsporidia K79 in vivo could be divided into the following five stages: sporoplasm, schizont, sporont, sporoblast, and spore. The process was just the same as the of N. bombycis, but its development was slower than that of N. bombycis. Several differences in the fine structure of the spore under electron microscope, which could be important keys for the classification of microsporidia, were obtained. Anchoring disk and polaroplast lamella of the new microsporidian spore were disclosed to be different from those of N. bombycis. An average number of polar filament coils of the new microporidian spore was 16 at an angle of 75$^{\circ}$. On the basis of various keys for the classification of microsporidia, the results obtained from various experiments proved that the newly isolated microsporidia should be classified into the Genus, "Nosema", nut is further classification for species should be conducted in the future. Therefore, it may be reasonable that the new microsporidia is temperally classified as Nosema sp. K79 considering the fact that it was discovered in Korea in 1979.a in 1979.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.147-159
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• 2002

Weathered bentonites occcur as surficial alterations of some domestic bentonite deposits in the Tertiary formations, with the thickness of less than about 50 cm, along naturally-formed weathering surface with slopping in gentle. 7 $\AA$-halloysite was found together with montmorillonite in the weathered bentonite. Compared to normal bentonite, the weathered one is generally more clay-rich and contains little amounts of original rock-forming minerals and residues. In the electron microscopy, fine-scale occurrence of the clay minerals tends to be somewhat discrete and segregated rather than closely associated. h curled margin of montmorillonite lamella is deformed to become obtuse in the weathered bentonite. Halloysite occurs as acicular to tubular crystals with the length of less than 2 $\mu$m and the width of about 0.3 $\mu$m, which commonly forms bundle-shaped aggregates. Electron microscopic observations on the fine-scale occurrence and texture of the wtathered bentonites indicate that the clay mineral transition from montmorillonite to halloysite has undergone without accompanying any intermediate phases of both clay minerals such as a mixed-layered type (M/H). The alteration reaction between these two clay minerals probably took place in the form of dissolution and precipitation mechanism in oxidation condition. An intense chemical leaching of SiO$_2$, Na, K and Ca might occur during the alteration reaction, forming a lot of dissolution cavity and residual concentration of A1$_2$O$_3$ and Fe, relatively. As the result of the chemical change, a fsvorable condition for halloysite formation seemed to be provided.

• Journal of fish pathology
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• v.4 no.2
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• pp.87-94
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• 1991

In the late summer of 1990 and 1991, mass mortality occured among cage-cultured grouper, Epinephelus septemfasciatus in south cost of Korea. The moribund fish didn't feed and became pale or dark chestnut colour and irregularly swimmed due to the loss of equilibrium, finally the diseased fish fell down side away on the bottom or the surface of cage showing the bent of body and died. The diseased fish showed the extensive hemorrahge in brain, the swelling of spleen and bile duct as the specific syptoms of internal organs. So the gill, skin and other organs of the diseased fish were examined for the presence of pathogenic parasites and bacteria. The parasitic Trichodina sp. were detected only from the gill lamella of the diseased fish, but these parasites seemed to be not a direct causative agents that induced the gross mortality of the cultured grouper. because these parasites were also observed in normal grouper, yellowtail, red seabream and rock bream co-cultured with the diseased grouper in same or near cages. In the viral examination, although isolation of the causative agent by the use of estabilshed cell Lines, RTG-2 and CHSE-214, was not succeed, the normal grouper inoculated intramuscularly with the filtered homogenate of the organs of the diseased fish showed the same external and internal signs with the naturally infected grouper. They died within a week. By using the naturally and the artificially infected fishes, electron microscopic observation revealed numerous hexagonal or polygonal particles in the cytoplasm of liver cells. Based on the these results, we suggest that the mass mortality of the cultured grouper would be occurred by the infection of a viral agent.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.241-249
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• 2006

Purpose For the reconstruction of craniofacial deformities, the distraction osteogenesis is an useful method which can make new soft tissues as well as new bone. Although the distraction osteogenesis is an effective procedure in quantitative aspects, the new bone formed by this procedure can be coarse in qualitive aspects sometimes. Materials and methods Twelve rabbits, weighing about 2 kg, were included and the prefabricated distraction device were used. After a latency period of 5 days, in the experimental group (n=6), the mandible was distracted at the rate of 1.0 mm/day for 2 days and then compressed with 1.0 mm for the next 3rd day, therefore distracted totally to a length of 1.0 mm for 3 days. This procedure was repeated 5 times and, as a result, the experimental group was distracted to a length of 5.0 mm for 15 days finally. In the control group (n=6), the mandible was distracted totally to a length of 5.0 mm at the rate of 1 mm/day. At 2 weeks and 8 weeks of consolidation in the control group, 3 rabbits in each group were sacrificed and their biopsy specimens from the distracted mandible were taken. Results All animals showed the mandibular elongation clinically and radiographically. Histologically, many blood vessels, osteoblasts and immature bones formed by osteoid deposition were observed in the experimental group at 2 weeks. At 8 weeks, the bony trabeculae were thicker than the ones in the control group and were composed of lamella bones and woven bones in the experimental group. On histomorphometric analysis, the bone deposition area of the distracted site was broader in the experimental group $(273.8{\pm}115.7\;cm^2)$ than the one in the control group $(199.4{\pm}101.4\;cm^2)$. Futhermore, the modified rate of bone deposition area was higher in the experimental group (48${\pm}$20%) than the one in the control group (35${\pm}$18%). However, these data showed no significant differences statistically. Conclusion These results suggest that the distraction osteogenesis by using an alternating distraction/compression protocols is an effective method for increasing new bone formation in distracted areas.

• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.32-38
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• 1999

A Saprolegnia sp. was isolated from cultured snakehead, Channa argus, and its physiological characteristics were investigated. The optimum temperature, pH and NaCl concentration for mycelial growth of Saprolegnia sp. were $25^{\circ}C$, 6.0 and 0%, respectively. The mycelial growth was increased with the addition of 10 mM phosphate and 10mg/L casamino acid. The essential oils extracted from three plants, Artemisia princeps var. orientalis, Thuja orientalis and Chamaecyparis obtusa have been tested to know whether they inhibit the growth of Saprolegnia sp. at six different oil concentrations(10, 100, 500, 1,000, 1,500 and 2,000 ppm). Essential oil from A. princeps var. orientalis began to inhibite the mycelial growth of Saprolegnia sp. at the concentration more than 10ppm. Using other essential oils from T. orientalis and C. obtusa, those initially inhibited the mycelial growth of Saprolegnia sp. at the concentration over 10 ppm and complate inhibition of mycelial growth was observed at over 500 ppm. The histopathological features of Snakehead infected by Saprolegnia sp. were studied. A club shape of gill lamella epithelial cells was observed in the gill. The mycelial cells were penetrated into muscular tissue, and the accumulation of the ceroid was observed in the liver, spleen and kideny tissue in common. The necrosis of tubular epithelial cells was seen in the liver tissue, parenchymal tissue in the spleen and tubular epithelial cells in the kidney.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.627-633
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• 1997

Gonad structure, germ cell development and reproductive cycle of the smallmouth scorpionfish, Scorpaena miostoma were investigated based on histological method. Samples were collected monthly in the vicinity of Suyoung Bay, Pusan, Korea from November 1995 to October 1996. The testis is seminiferous tubule type in internal structure. Seminiferous tubule consists of numerous testicular cysts which contain numerous germ cells in same developmental stage. The ovary consists of several ovarian lamellae originated from ovarian outer membrane. Oogonia originated from the inner surface of the ovarian lamella protrude to the ovarian cavity in oocyte stage, and they are suspended by the egg stalk. Biological minimum size of female and male were 12.5cm in total length. Gonadosomatic index (GSI) of female (3.81) and male (0.23) were the highest in October. Reproductive cycle was classified into the following successive stages: in female, growing stage $(May\~August)$, maturation stage $(September\~October)$, ripe and spawning stage $(November\~December)$, recovery and resting stage $(January\~April)$, and in male, growing stage $(June\~August)$, maturation stage $(September\~October)$, ripe and spent stage $(November\~January)$ and recovery and resting stage $(February\~May)$.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.6
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• pp.520-530
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• 2006

Undifferentiated mesencymal stem cells(UMSCs) have been thought to be multipotent cells that can replicate as undifferentiated cells and that have the potential to differentiate into lineages of mesenchymal tissue including the bone, cartilage, fat, tendon, muscle, and marrow stroma. It can be used to sinus lifting, Guided bone regeneration, other bone graft in dental part. The purpose of this study is to evaluate the effect of mesencymal stem cells on sinus augmentation with autogenous bone, fibrin glue mixture in a rabbit model. 8 New Zealand white rabbits were divided randomly into 4 groups based on their time of sacrifice(1, 2, 4 and 8 weeks). First, undifferentiated mesenchymal stem cells were isolated from iliac crest marrow of rabbits and expanded in vitro. cell culture was performed in accordance with the technique described by Tsutsumi et al. In the present study, The animals were sacrificed at 1, 2, 4 and 8 weeks after transplantation, and the bone formation ability of each sides was evaluated clinically, radiologically, histologically and histomorphologically. According to the histological observations, Stem cell group showed integrated graft bone with host bone from sinus wall. At 2 and 4weeks, It showed active newly formed bone and neovascularization. At 8 weeks, lamella bone was observed in sinus graft material area. Radiologically, autobone with stem cell showed more radiopaque than autobone without stemcell. there were significant differences in bone volume between 2 and 4 weeks (p<0.05). In summary, the autobone with stem cells had well-formed, newly formed bone and neovasculization, compared with the autobone without stem cells (esp. 2 weeks and 4 weeks) The findings of this experimental study indicate that the use of a mixture of mesenchymal stem cell yielded good results in osteogenesis and bone volume comparable with that achieved by autogenous bone. Therefore, this application of this promising new sinus floor elevation method for implants with tissue engineering technology deserves further study.