• Journal of Chest Surgery
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• v.37 no.4
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• pp.307-312
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• 2004

With the development of cardiac surgical technique, we need more prosthetic materials for repairing the intra- and extracardiac defects. Although bovine pericardial bioprosthesis treated with glutaraldehyde (GA) solution is one of the most popular materials, it has a drawback of later calcific degeneration. The purpose of this study is to investigate the effectiveness of several materials and methods in reducing the calcific degeneration of bovine pericardium. Material and Method: Forty square-shaped pieces of bovine pericardia were fixed in 0.625% GA solution with 4 g/L MgCl$_2$ㆍ6$H_2O$ as a control group (group 1). Other 40 pieces pre-treated with 1 % SDS(group 2) and 40 pieces post-treated with 8% glutamate (group 3) and 2% chitosan (group 4) were also fixed in the same GA solution. Other 40 pieces pre-treated with 1% SDS and post-treated with 8% glutamate and 40 pieces post-treated with 2% chitosan were also fixed in the same GA solution (group 5, 6). The pericardial pieces were implanted into the belly of 40 Fisher 344 rats subdermally and were extracted 1 month, 2 months, 3 months, and 6 months after the implantation. With an atomic absorption spectrophotometry, we measured the calcium amount deposited and examined the tissue with microscope. Result: The calcium deposition in 1 month was less in group 2, 5, 6 than that in group 1 (p＜0.05). It was most prominent in group 5 (p＜0.01). This finding continued in 2 month. In 3 month, the calcium deposition was less in group 3 and 4 as well as group 2, 5, and 6 than in group 1. In 6 month, the calcium deposition in group 2, 3, 4, 5, and 6 was less than that in group 1 and the difference was more than that of 1, 2, and 6 month. The microscopic calcium deposition was also less in group 2 and 5. Calcium deposition developed in the whole layer of pericardium, beginning with the surrounding the collagen fiber and progressing inwardly. Conclusion: Pre-treatment with SDS, post-treatment with glutamate or chitosan, and SDS pre-treatment and post-treatment with glutamate or chitosan were effective in reducing the calcium deposition in bovine pericardium. Moreover, the combined method of SDS pre-treatment and glutamate post-treatment was more effective than other methods.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.89-92
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• 2001

The effect of topical application with 5,10 and 15 $\mu$g/ ml androstenedione and methyltesterone to the fifth stadium larvae of the si1kworm,B. mori on fat body glycogen, protein, tota1 lipids, phospholipids, neutral lipids and haemolymph trehalose and protein has been studied. The fat body glycogen increased significantly in all the treated groups except in the 15$\mu$g/ml androstenedione treated group. However the fat body glyco- gen increased significantly in 10 ${\mu}g$/ml methyltesterone treated group. The androstenedione treated groups showed increased haemolymph trehalose but the increase was not significant. However the haemolymph trehalose increased significantly in all the methyltestosterone treated groups. The fat body protein decreased in all the androstenedione and methyltesterone treated groups except 15 ${\mu}g$/ml methyltesterone where the decrease in fat body protein was significant. Whereas that of haemolymph protein significantly decreased in all the groups except in the group treated with 5 ${\mu}g$/ml androstenedione where the decrease was not significant. The total lipids, phospholipids and neutral lipids of the fat body decreased significantly in all the groups treated with androstenedione and methyltestosterone when compared with those of carrier control.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.254-257
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• 2007

In this study, hydroformability and mechanical properties of pre- and post- heat treated Al6061 tubes at different extrusion type were investigated. For the investigation, as-extruded, full annealed and T6-treated Al 6061 tubes at different extrusion type were prepared. To evaluate the hydroformability, uni-axial tensile test and free bulge test were performed at room temperature and $200^{\circ}C$. Also mechanical properties of hydroformed part at various pre- and post-heat treatments were estimated by tensile test. And the tensile test specimens were obtained from hexagonal prototype hydroformed tube at $200^{\circ}C$. As for the heat treatment, hydroformability of full annealed tube is 25% higher than that of extruded tube. The tensile strength and elongation were more than 330MPa and 12%, respectively, when hydroformed part was post-T6 treated after hydroforming of pre- full annealed tube. However, hydroformed part using T6 pre treated tube represents high strength and low elongation, 8%. Therefore, the T6 treatment after hydroforming for as-extruded tube is cost-effective. Hydroformability of Al6061 tube showed similar value for both extrusion types. But flow stress of seam tube showed $20{\sim}50MPa$ lower value.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.941-945
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• 2015

We examined the in vivo efficacy of ultra-high molecular weight poly-γ-glutamic acid (UHMW γ-PGA) for wound healing. The wound area was measured by a ruler and documented by digital photography before the animals were sacrificed at days 8 and 16 post wounding. The areas of wounds treated with UHMW γ-PGA were significantly decreased on days 8 and 16, as compared with those receiving a control treatment, and more than 70% of the UHMW γ-PGAtreated area was repaired by day 8. Hematoxylin and eosin staining confirmed that the epidermis had regenerated in the UHMW γ-PGA-treated wounds. At 16 days post wounding, collagen pigmentation and cross-linking were increased as compared with the control groups, and greater regeneration of blood vessels had occurred in UHMW γ-PGA-treated groups. Increased levels of transforming growth factor-beta and β-catenin were also observed in skin samples collected from UHMW γ-PGA-treated animals on days 8 and 16 post incision. Taken together, these findings suggest that UHMW γ-PGA promotes wound healing in vivo.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.132-135
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• 2007

In this study, hydroformability and mechanical properties of pre- and post- heat treated Al6061 tubes at different extrusion type were investigated. For the investigation, as-extruded, full annealed and T6-treated Al6061 tubes at different extrusion type were prepared. To evaluate the hydroformability, uni-axial tensile test and free bulge test were performed at room temperature and $250^{\circ}C$. Also mechanical properties of hydroformed part at various pre- and post-heat treatments were estimated by tensile test. And the tensile test specimens were obtained from hexagonal prototype hydroformed tube at $250^{\circ}C$. As for the heat treatment, hydroformability of full annealed tube is 25% higher than that of extruded tube. The tensile strength and elongation were more than 330MPa and 12%, respectively, when hydroformed part was post-T6 treated after hydroforming of pre- full annealed tube. However, hydroformed part using T6 pre treated tube represents high strength and low elongation, 8%. Therefore, the T6 treatment after hydroforming for as-extruded tube is cost-effective. Hydroformability of Al6061 tube showed similar value for both extrusion types. But flow stress of seam tube showed $20{\sim}50MPa$ lower value.

• Restorative Dentistry and Endodontics
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• v.13 no.1
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• pp.151-158
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• 1988

The purpose of this study was to evaluate the effect of canal filling methods and post-space preparation time on the apical seal of endodontically treated teeth. Seventy-six single-rooted human teeth were divided into 6 groups and each tooth was obturated and prepared post-space according to the purpose of this study. After all specimens were immersed in Indian ink, decalcified and cleared, the degree of dye penetration into the root canals observed by magnifying glass (X20) and measured by caliper. The results were as follows: 1. In the thermatic condensation, no significant difference in ink penetration occured when the post-spaces were created immediately after obturation or when they were made a week later. 2. In the lateral condensation, no significant difference in ink penetration existed between teeth whose post-space were prepared immediately or delayed. 3. In comparison of experimental groups and control groups, no significant difference showed when the groups were obturated with McSpadden compactor but when the teeth were laterally condensed, the experimental groups showed less ink penetration than controls. 4. Thermatic condensed teeth with McSpadden compactor were less ink penetration thn laterally condensed teeth.

• Carbon letters
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• v.8 no.2
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• pp.127-133
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• 2007

In this study, commercially available pitch-based carbon fibers of general grade were post-heat-treated using a boxtype high temperature furnace at $1800^{\circ}C$, $2000^{\circ}$, $2200^{\circ}C$, and $2400^{\circ}C$, respectively. The fundamental characteristics of each heat-treated carbon fibers were investigated in terms of chemical composition, morphology, thermal stability, X-ray diffraction, single filament tensile test, and electrical resistivity. The result showed that the fiber properties were significantly influenced by the post-heat-treatment, indicating the greater effect with increasing treatment temperature. The carbon contents, thermal stability, and tensile properties of the carbon fibers used here were further increased by the post-heat-treatment, whereas the d-spacing between graphene layers and the electrical resistivity were reduced with increasing post-heat-treatment temperature.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.26-32
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• 2014

We investigate the effect of post-conditioning periods and seed orientation on the vigor of cucurbit seeds with dry heat treatment (DHT). All the dry-heat treated seeds exhibited varying degree of seed vigor decreases. In general, pumpkin seeds showed less vigor decreases than the bottle gourd seeds. When the dry heat treated seeds were germinated after post-conditioning for 0, 30, and 120 days, the percentage of germination was enhanced by increasing the period of post-conditioning and the efficiency of post-conditioning differed by crop and cultivar. In both bottle gourd and pumpkin, the vigor of seeds placed in vertically upward and horizontal orientations was higher than that of the seeds placed in the vertically downward orientation. The results suggested that the vigor of dry-heat treated seeds could be improved by applying the proper post-conditioning and seed orientation.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.69-73
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• 2001

The effect of topical application 100,300 and 500 $\mu$g/ ml with Mineral Salts of magnesium sulphate and potassium nitrate on economic parameters was ana- lyzed following treatment of last larval stadium. The treated larvae showed significantly decreased larval weight and silk gland weight in all the treated groups along with other decreased Iarval, cocoon and adult parameters. The female cocoon weight was significantly decreased in all the treated groups with decreased female cocoon shell weight and male cocoon weight at 300 and 500$\mu$g/ml respectively. The length and weight of filament was significantly decreased at 300 and 500 $\mu$g/ml respectively and denier at 500 $\mu$g/ ml. The fecundity decreased significantly in 300 and 500 $\mu$g/ml treated groups when compared with the corresponding parameters of the carrier control.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.83-88
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• 2001

The effect of topical application with 200,400 and 600 $\mu$g/ml 2,4-dichlorophenoxyacetic acid (2,4-D) on the fifth larval stadium of the silkworm, B. mori, was analyzed. Larvae treated during fifth larval stadium enhanced larval, cocoon and adult parameters. The larval period was significantly decreased with increase in silk gland weight at 400 and 600 $\mu$g/ml, male cocoon weight and shel1 weight in all the treated groups and filament length and weight at 200 $\mu$g/ml treated group. Length of the ovariole, eggs per ovariole and hatching percentage increased significantly in all the treated groups when compared with those of the carrier control. This suggests that the plant growth regulator 2,4-D in addition to affecting silk production also affect reproductive performance.