• Elastomers and Composites
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• v.49 no.3
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• pp.225-231
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• 2014

In this study, we used polypropylene grafted with itaconic acid (PP-g-IA) as a compatibilizer to prevent phase separation phenomenon which occurs upon blending polypropylene (PP) and ethylene-vinyl alcohol copolymer (EVOH). A compatibilizer was prepared using graft copolymerization of itaconic acid (IA) onto PP where input ratio of IA was 1, 2, 5, and 10 wt.%. To confirm the structure of PP-g-IA and the graft ratio of IA onto PP, we used $^1H$ NMR and FT-IR. We tested the compatibilizer which has highest graft ratio of 1% in immiscible PP/EVOH blends. The morphologies of PP/PP-g-IA/EVOH blends were analyzed by SEM. Thermal and mechanical properties of the blends were analyzed by DSC and UTM. PP-g-IA enhanced the interfacial adhesion of PP and EVOH copolymer.

• Archives of Reconstructive Microsurgery
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• v.21 no.1
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• pp.68-75
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• 2012

Purpose: The purpose of this study was to evaluate the clinical results of the 4+5th extensor compartmental artery pedicled vascularized bone graft in advanced Lichtman stage III Kienbock's disease. Materials and Methods: Eight patients with advanced Lichtman stage III Kienbock's disease who underwent the 4+5th extensor compartmental artery pedicled vascularized bone graft and followed up more than 1 year were analyzed retrospectively. There were 3 men and 5 women. The mean age was 43.6 years old. Two patients were Lichtman stage IIIA and six patients were IIIB. The clinical outcomes were evaluated with radiocarpal joint pain, range of motion, grip strength, carpal-height ratio, radioscaphoid angle, return to daily living activity and/or work. The mean follow up period was 38.5 months (range from 12 to 86 months). Results: On last follow up, the pain was disappeared in 6 patients, and mild occasional pain was remained in 2 patients. Mean radiocarpal joint flexion and extension were 55 degrees and 60 degrees, 87% and 88% of the normal side, respectively. The carpal-height ratio was maintained or improved in 6 patients and slightly decreased in 2 patients. Radioscaphoid angle were improved or maintained in 7 patients. Mean grip strength was 67 lb, 93% of the normal side. All 8 patients returned to daily living activities and/or their previous works. Conclusion: The 4+5th extensor compartmental artery pedicled vascularized bone graft prevented the progression of disease and provided clinical improvement even in advanced Lichtman stage III Kienbock's disease.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.77-80
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• 2006

Graft copolymerized polycarboxylate(PC)-type superplasticizers(PCs) which have carboxylic acid with $\pi$ bond among the molecular structure and polyethyleneglycol methyl ether methacrylate(PMEM) were synthesized by free radical reaction and investigated the chemical structure, polymerization condition, and physical and chemical properties. Also, the effects of PCs in the dispersion, adsorption and hydration of cement were evaluated. As the molecular weight of graft chain decreases, the adsorption amount on cement particles increased. It was advantageous for the flow to reduce molar ratio, the lower the side bone molecular weight, and increase the molar ratio, the larger the side bone molecular weight. The hydration reaction speed was highly delayed at day 1, due to increase in molar ratio and reduction in side bone molecular weight, but it was recovered in the days after.

• Journal of Chest Surgery
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• v.26 no.5
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• pp.355-359
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• 1993

Ten consecutive patients with abdominal aortic aneurysm were treated in Chungnam National University Hospital from May of 1985 to June of 1993. Pulsating palable mass was the most common first sign [7 patients]. The ratio of male to female was 8:2. The age ranged from 53 to 73 years with mean age of 65 years. The etiology and location of the aneurysm was atherosclerosis and infrarenal aorta in all. Dacron graft interposition [straight graft-1, bifurcation graft-7] and wrapping with aneurysmal sac were performed in 8 patients. In one patient with infected abdominal aortic aneurysm, we performed aneurysmectomy and left axillo-bifemoral bypass with 8 mm PTFE graft. And in another patient with complete thrombotic obstruction of infrarenal aortic aneurysm, we performed the suturing of the proximal part of the abdominal aortic aneurysm and aorto-bifemoral bypass with 18 x 9 mm PTFE graft. There was one operative death with the mortality rate of 11 % and 8 complications in 4 patients; ARF[2], duodenal ulcer[1], mechanical ileus[1], genitourinary dysfunction[2] and wound infection with abdominal abscess[1]. Because of the high operative mortality after rupture of the aneurysm, we think it is better to operate on early at the diagnosis of abodominal aortic aneurysm is made.

• Journal of the Korean Chemical Society
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• v.26 no.3
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• pp.179-187
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• 1982

The copolymerization of N-acryloylpyrrolidone and acrylonitrile was performed in N,N'-dimethylformamide at 50$^{\circ}$C and monomer reactivity ratio was obtained by using IR working curve and Fineman and Ross equation. ($r_1$ = 0.43, $r_2$ = 1.56) It is found that resulting copolymer is good polymeric initiator for anionic graft copolymerization of 2-pyrrolidone. Graft copolymers with polybutylamide (nylon-4) grafts onto poly(NAP-Co-AN) backbone were synthesized and the various effects on the graft copolymerization of 2-pyrrolidone were examined. The rate constants ($K_p$) of graft anionic polymerization at 40 and 50$^{\circ}$C were 2.82${\times}$10 and 2.93${\times}$10(l/mole, min), respectively.

• Archives of Plastic Surgery
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• v.50 no.6
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• pp.610-614
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• 2023

Necrotizing fasciitis is an uncommon yet fatal soft tissue infection. Current recommended treatment includes antibiotics with repeat surgical exploration and wound debridement followed by reconstruction. In burn patients, the Meek micrograft has demonstrated a higher true expansion ratio, faster reepithelialization rate, more resilient toward infection, and reduced risk of graft failure as compared with meshed graft. To our best knowledge, the use of Meek micrografting technique in reconstruction of postdebridement wounds of necrotizing fasciitis has not been reported. Hereby, we present a case of a 57-year-old gentleman who was referred to us for wound reconstruction after surgical debridement of Fournier's gangrene and extensive necrotizing fasciitis involving the anterior abdomen and bilateral femoral region. Meek micrografting technique was used to reconstruct the anterior abdomen as the wound bed was large. Although the graft was complicated with a small area of localized infection, it did not spread across the entire graft and was successfully treated with topical antibiotics and regular wound dressing. In our case, wound reconstruction using Meek micrografting technique in a patient with extensive necrotizing fasciitis was successful and showed positive outcome. Therefore, we suggest further studies to be conducted to investigate the applications and outcomes of the Meek micrografting technique, especially in patients with extensive wound bed and limited donor site availability.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.45.1-45.8
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• 2015

Background: Radial forearm free flap is the most reliable flap for intraoral soft tissue reconstruction after cancer ablation surgery. However, unesthetic scar of the donor site and the need for a second donor site for skin graft are major disadvantages of the forearm flap. The purpose of this study was to report the clinical results of double-layered collagen graft to the donor site of the forearm free flap without skin graft. Methods: Twenty-two consecutive patients who underwent oral cancer ablation and forearm reconstruction between April 2010 and November 2013 were included in this study. Male to female ratio was 12:10, and average age was 61.0 years old (27-84). Double-layered collagen was grafted to the donor site of the forearm free flap and healed for secondary intention. Upper silicone had been trimmed at the periphery during secondary intention, and dry dressing was used. Postoperative scar healing and esthetic results and function were evaluated. Results: An average follow-up period was 34.9 months. The scar area was decreased to 63.9 % in average. The complete healing was obtained between 1.5 and 3 months according to the defect size. There was no functional defect or impairment 3 months after operation. All patients were satisfied with the esthetic results. Three patients died of recurred cancer. Conclusions: Double-layered collagen graft was successfully performed in this study. Without the thigh skin graft, patients had experienced less painful postoperative healing periods and discomfort.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.219-222
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• 1998

The space charge and conduction characteristics of chemically modified vinylpyridine (VP) grafted low density polyethylene (LDPE) was investigated. VP grafted LDPE was analyzed by elemental analysis (EA) to confirm the grafting reaction. Homocharge was developed in VP grafted LDPE at low graft ratios and changed to heterocharge with increasing the content of VP. In conduction experiment, current densities of VP grafted LDPE were lower than that of LDPE and VP grafted LDPEs showed almost the same conduction characteristics as vinylpyridine graft ratio increased

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1196-1198
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• 1997

In this work, simultaneous measurement such as change distribution and electrical conduction of maleic anhydride grafted XLPE was investigated. Heterocharge was found in XLPE and it decreased with increasing MAR graft ratio in XLPE-g-MAH. Conduction currents also decreased with increasing MAR graft ratio. The relationship between the space change behavior and the electrical conduction characteristics in XLPE-g-MAH is discussed.

• Journal of Korean Society of Forest Science
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• v.22 no.1
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• pp.49-62
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• 1974

1. In the comparison of survival ratio among three different methods(bark graft, veneer graft, root graft), bark graft showed the highest survival ratio and root graft was the lowest. It was shown to be significant at the level of 5% in the analysis of variance for the results. It was able to be supposed that one of the main causes for the results was the different amounts of ferric tannic acid which was formated owing to the reaction of grafting knife with tannic acid oozing from cutting faces of the tree. In juvenile tissue graft, the survival ratio of inverted radicle graft was a little higher than that of juvenile stem graft, but there was no significant difference between two methods in analysis of variance. 2. The most hairs of chestnut tree leaves were recognized as stellates on the most part of leaves except for venation. The number of rays in the stellates was ranged from 4 to 8 generally. It was shown to be highly significant differences at the level of 1% among the each race growing at the similar environmental condition in the length of ray and the distributed ratio of the stellates having different ray number. 3. Excepting for the basal width of serration there were no significant differences between $Imakita_1$, $Imakita_2$ as well as between $Teteuchi_1$, $Teteuchi_2$ at the each point of experimental items in this study. Such results made this study more useful. 4. Among the races that were growing in the similar environmental condition, there were highly significant differences at the level of 1% in the length and the width of serration. 5. The rolling of hair, the angle of serration from the leaf margin, the existence of lateral vein in the serration, the intrusion of main vein into the serration and the width of main vein were observed to be somewhat useful as the subsidiary methods for the identification of chestnut races.