• Korean Journal of Plant Tissue Culture
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• v.25 no.6
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• pp.495-500
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• 1998

Ultrastructural changes of the isolated and cultured protoplasts from ginseng (Panax ginseng C. A. Meyer) callus were studies with electron microscopy. In the 3-day-cultured protoplasts, the cell organelles such as rough endoplasmic reticulum, ribosome, Golgi complex, mitochondria, proplastid increased in number and observed microtubules. Many vesicles derived from the Golgi complex were evenly distributed in the cytoplasm. Some of such vesicles protruded the outer surface of the plasmalemma, and formed the protuberances. Vacuole derived from endoplasmic reticulum included Golgi vesicles by the invagination of vacuoles. These vacuoles migrated toward the plasmalemma by a fusion process (exocytosis), after fusing the plasmalemma the cell wall materials released from the outer surface of the plasmalemma, and lastly deposited on the plasmalemma. Proplastids containing many starch grains, and microtubules parallel to the plasmalemma were observed near the plasmalemma. Connected fibrils which were observed on the outer surface of the 3-day-cultured protoplast were interpreted as the component of cellulose.

• Korean Journal of Veterinary Research
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• v.39 no.5
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• pp.855-864
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• 1999

Hemal nodes and hemolymph nodes are lymphoid organs that share morphologic and functional characteristics of lymph nodes and spleens. The aim of the present study was to obtain new informations on the distinct morphological structures of hemal nodes and hemolymph nodes according to ages, and to get the basic data for their functions in Korean native goats. Goats were divided into 5 groups, consisting of 3 animals aged 1, 3, 6, 10 and 12 months, respectively. Ultrastructural features of the organs were observed by transmission and scanning electron microscopes. The sinuses of hemal nodes and hemolymph nodes were lined by endothelial-like reticular cells which had euchromatin-rich nuclei and many cytoplasmic processes, surrounding collagen fibrils. Macrophages containing phagocytosed erythrocytes were often noted in the diffuse lymphatic tissues of hemal nodes and hemolymph nodes. Some mast cells were in contact with the plasma cells near the blood vessel. Hemal nodes and hemolymph nodes had venous sinusal-like vessels which were different from the deep sinus. The lymph vessels with valves were observed in the capsule of the hemolymph node. There were no ultrastructural differences of the organs in the age different groups of the animals. These results suggest that hemal nodes and hemolymph nodes may take part in hemopoiesis, blood filtration and immune reaction in Korean native goats.

• Journal of Periodontal and Implant Science
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• v.45 no.4
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• pp.136-144
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• 2015

Purpose: The objective of this study was to comparatively assess the bone regenerative capacity of absorbable collagen sponge (ACS), biphasic calcium phosphate block (BCP) and collagenated biphasic calcium phosphate (CBCP) loaded with a low dose of recombinant human bone morphogenetic protein-2 (rhBMP-2). Methods: The CBCP was characterized by X-ray diffraction and scanning electron microscopy. In rabbit calvaria, four circular 8-mm-diameter defects were created and assigned to one of four groups: (1) blood-filled group (control), (2) rhBMP-2-soaked absorbable collagen sponge (0.05 mg/mL, 0.1 mL; CS group), (3) rhBMP-2-loaded BCP (BCP group), or (4) rhBMP-2-loaded CBCP (CBCP group). The animals were sacrificed either 2 weeks or 8 weeks postoperatively. Histological and histomorphometric analyses were performed. Results: The CBCP showed web-like collagen fibrils on and between particles. Greater dimensional stability was observed in the BCP and CBCP groups than in the control and the CS groups at 2 and 8 weeks. The new bone formation was significantly greater in the BCP and CBCP groups than in the control and CS groups at 2 weeks, but did not significantly differ among the four groups at 8 week. The CBCP group exhibited more new bone formation in the intergranular space and in the center of the defect compared to the BCP group at 2 weeks, but a similar histologic appearance was observed in both groups at 8 weeks. Conclusions: The dose of rhBMP-2 in the present study enhanced bone regeneration in the early healing period when loaded on BCP and CBCP in rabbit calvarial defects.

• Polymer(Korea)
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• v.24 no.6
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• pp.810-819
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• 2000

Poly(p-hydroxybenzoate) (PHB)/poly(ethylene terephthalate) (PET) 8/2 thermotropic liquid crystalline copolyester, poly(ethylene 2,6-naphthalate) (PEN), and PET ternary blend was spun to fiber by melt spinninB process, and tensile properties of the fibers were measured. The matrix of the fibers, PET and PEN, were dissolved in ο-chlorophenol at 55$^{\circ}C$ for 2 hours, and the liquid crystalline polymer fibrils were observed using a scanning electron microscope. Halpin-Tsai equation for modulus calculation of short fiber reinforced composite and the rule of mixture for continuous reinforcement composite were modified, and the tensile modulus were calculated and compared with experimental modulus. To minimize difference between the theoretical and the experimental moduli, dimensionless viscosity constant (K) was given and used to modify two equations. The theoretical tensile modulus using the newly modified equations presentel a similar to the experimental tensile modulus of composite, and the modified equations presented a unique way to determine the tensile modulus of the liquid crystalline polymer reinforced thermoplastic composites.

• Applied Microscopy
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• v.27 no.1
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• pp.31-46
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• 1997

Ultrastructure of mouse thymus was evaluated, following the administration of potassium dichromate and mercuric chloride, the heavy metals of evironmental pollutants. Potassium dichromate (20 mg/kg) or mercuric chloride solutions (10 mg/kg) were subcutanously injected to the mice. Six hours, three days and two weeks after the injections, animals were sacrificed. Thymic tissues were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde solutions. The procedure was followed by the fixation in 1% osmium tetroxide solutions. Washed and dehydrated tissue-blocks were embedded in the araldite mixture. Ultra-thin sections were stained with uranyl acetate-lead citrate solutions. Results observed were as follows: 1. In electron microscopy, cortical population of thymocytes in the thymus of experimental groups were reduced. especially in the outer cortex. Subcapsular cortices of potassium dichromate treated mice were filled with many epithelial reticular cells, whereas the similar area of mercuric chloride-treated mice exhibited large intercellular spaces. 2. In the thymus of mercuric chloride treated group, large intercellular spaces were formed by shrinkage of epithelial reticular cells, and the space was invaded by numerous cytoplasmic projections of macrophages. Thymocytes nuded out from the shrunken cytoplasm of epithelial reticular cells, presented numerous microvilli. 3. In the thymus of potassium dicromate treated group, many activated macrophages and plasma cells migrated into thymic cortices. 4. In the perivascular spaces of thymic cortices of potassium dichromate- and mercuric chloride-treated mice, activated macrophages. plasma cells, collagen fibrils, and flocculent substance of exudated materials were exhibited. From the above findifgs, it was concluded that potassium dichromate or mercuric chloride could disturb the normal differentiation or 'education' of T cells in the thymic cortex. In turn, these heavy metals may hurt the immunological defense mechanism.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.7-17
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• 1982

The purpose of this study was to investigate the fine structural modifications of fibroblasts in the coronal region of inflamed human pulps from carious teeth. Six untreated human teeth with large carious lesions and two normal teeth as control were selected from male and female patients between the ages of 20 and 39. The teeth were divided into 4 groups by light microscopic findings: the normal control group, the chronic inflammatory cell-appeared group, the acute and chronic inflammatory cell-appeared group, and the total necrosis group. All tissues were fixed in 2.5% glutaraldehyde in 0.1M sodium cacodylate buffer at pH 7.4 and 1% osmic acid in same buffer. They were embedded in Epon 812. The ultrathin sections were stained conventionally and examined with a AEI Corynth 500 electron microscope. The results were as follows; 1. The fibroblasts of the normal pulps were almost in a quiescent state. 2. The active and the quiescent fibroblasts were found in the pulps of the chronic inflammatory cell-appeared group. Lymphocytes and plasma cells were also seen scattered among these fibroblasts. 3. In the pulps of the acute and chronic inflammatory cell-appeared group, active, degenerative and necrotic fibroblasts were found in the PMN appeared area. And all the fibroblasts in the fibrosis area were active. In the area of chronic inflammatory cellular infiltration, almost all the fibroblasts were active, but seldom were quiescent fibroblasts observed. Some fibroblasts in the pulps of two teeth had large vacuoles that contained banded collagen fibrils. The phagosomes had small beaded vesicles or large lysosome-like varicosity. In two of the teeth, microorganisms were present and two morphological shapes were identified, a rod and a coccus. 4. Vacuolar, vesicular, lamellar, fibrous and myelin structures were observed in the pulp of the total necrosis group, and cocci were also seen.

• Polymer(Korea)
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• v.30 no.2
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• pp.175-181
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• 2006

Hybrid process of thermally-induced phase separation and stretching was developed for the preparation of microporous polypropylene hollow fiber membranes. Precursor for stretching was prepared by using soybean oil as a diluent and benzoic acid as a nucleating agent far the sphenlite control and it was stretched far the micrporous hollow fiber membrane. The effects of stretching ratio and deformation rate for stretching process were investigated. Increase of stretching ratio resulted in the greater pore size with nonuniform size distribution. Higher deformation rate also increaser the pore size with uniform size distribution. Stretching ratio was closely related with the orientation of polymer chain and increased the mechanical strength of the fiber. Increase of deformation rate had little effects on the orientation of crystalline phase, and decreased the orientation of amorphous phase which caused the decrease of tensile strength of the fiber and broke the micro-fibrils connecting spherulites to form a circular pore shape.

• Journal of Adhesion and Interface
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• v.8 no.3
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• pp.9-15
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• 2007

The interfacial evaluation of surface modified Jute fiber/polypropylene (PP) composites before and after hydration was investigated using micromechanical test and dynamic contact angle measurement. The IFSS of alkaline and silane-treated Jute fiber/PP composites increased, whereas after hydration, the IFSS of the untreated, alkaline- and silane-treated Jute fibers/PP composites decreased due to swelled fibrils by water infiltration. The interfacial adhesion of silane treated fiber/PP composites was higher than alkaline-treated or the untreated cases. The surface energies of Jute fiber treated under various conditions were obtained using dynamic contact angle measurement. Especially after hydration, the thermodynamic work of adhesion was calculated by considering water interlayer, which indicated the stability of IFSS between silane treated Jute fiber and PP matrix showing better than others.

• YAKHAK HOEJI
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• v.49 no.2
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• pp.147-150
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• 2005

Macrophage scavenger receptors (MSRs) induce microglial interaction with ${\beta}$-amyloid fibrils (fA${\beta}$) that are associated with Alzheimer's disease (AD). Although microglia are know n to have a dual effect on formation of plaque and clearance of fA${\beta}$ in the AD brain, receptor-mediated phagocytosis is a very important tool for preventing amyloid plaque via activated microglia in the early stage of AD. In the study, we examined whether ginsonoside Rg3 enhances the microglial Phagocytosis of A${\beta}$1-42 through Phagocytosis assay, gene expression (RT-PCR) and protein assay (western blots) for the cell responsiveness presented between Rg3-treated and non-treated groups. Fluro-labeled Ac-LDL and E.coli particles were used as control proteins for phagocytosis. In previous studies, this was a particularly interesting property of Rg3 in the stimulation and phagocytosis of macrophages in the periphery. We report here that ginsenoside Rg3 increased the expression of type-A MSR (MSR-A) in microglia and thus accelerated the phagocytosis with an effective degradation of engulfed fA${\beta}$. This result suggests that Rg3 may play an important role in removing fA${\beta}$ by enhancing the receptor-mediated phagocytosis. In addition, Rg3 could be a potential candidate for balancing the rate of production of fA${\beta}$ in AD brain.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.481-481
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• 2007

This work describes the effect of the number of roll pressing and the composition of carbon black on the electric and mechanical properties of carbon-PTFE electrode, in which composition is MSP 20 : carbon black: PTFE = 95-x : x : 5 wt.%. It was found that the best electric and mechanical properties were obtained in sheet electrode roll-pressed for about 15 times and in sheet electrode, in which composition is MSP 20 : carbon black: PTFE = 80 : 15 : 5 wt.%. These behaviors could be explained by the network structure of PTFE fibrils and conducting paths linked with carbon blacks, respectively. On the other hand, cell capacitor using the sheet electrode with 15 wt.% of carbon black attached on aluminum current collector with the electric conductive adhesive, in composition is carbon black : CMC = 70 : 30 wt.%, has exhibited the best rate capability in the current range of $0.5mA/cm^2$ $100mA/cm^2$ and the lowest equivalent series resistance.