• Journal of the Optical Society of Korea
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• v.13 no.4
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• pp.484-488
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• 2009

We investigate the characteristics of the surface mode formed at the single interface between dual singly negative medium layers. It is shown that the interface can support a mode which has polarization degeneracy and a vanishing propagation constant. That is, this surface mode is a polarization-independent one that does not propagate at all through the interface. The corresponding electric and magnetic field distributions become static along the longitudinal (guiding) direction (but not along the transverse direction) resulting in the formation of transverse-electric/longitudinalmagnetic or transverse-magnetic/longitudinal-electric modes.

• Journal of the Korean association of regional geographers
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• v.10 no.4
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• pp.800-823
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• 2004

This paper aims at examining the ways in which foreign immigrant workers in South Korea have been "forgotten" and "marginalized" in the regulatory politics of globalization and how the politics of "forgetting" has influenced the formation of immigrant local communities in South Korea. More specifically, by focusing on the immigrant community in Wongok dong, Ansan, it explores the forming questions. First, under what conditions has Wongok' dong become one of the biggest communities for foreign workers in South Korea? Second, how has the growth of the Wongok-dong immigrant community been influenced by the politics of "exclusion", and "inclusion" taking place at various geographical scales? Based on this case study, this paper suggests that the practices of "exclusion" and "forgetting" should not be seen as an inevitable outcome of globalization; instead, they need to be seen as an outcome of political processes, in which the practices of "exclusion" and "inclusion" are intertwined with one another through interactions and negotiations among different interests and ideas that take place in the multi-scalar regulatory processes, which contribute to the (material and discursive) construction of globalization.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.1
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• pp.45-54
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• 1997

The purpose of this investigation was to determine the biomechanical property of calvarial defects reconstructed using toothash, plaster and tooth-plaster mixture. Full-thickness bony defects were made on the rat calvaria with size of $10mm{\times}10mm$. Group 1 was filled with toothash only, group 2 : toothash-plaster mixture, and group 3 : plaster only. The defects were allowed to heal for 12 and 20 weeks before killing the animals. Light microscopic examinations vas taken after 12 week after operation. The hardness was evaluated for test of mechanical property. The following results were obtained : 1. In light microscopic examination 12 week after operation, there were no inflammatory and foreign body reaction. Implanted particles were resorbed gradually or united directly with newly formed bone. 2. In hardness test, the hardness of newly formed bone was lower than that of normal bone and there was significant difference(P<0.01). The site of new bone formation has enough hardness to resist the mechanical stress. These results suggest that toothash and plaster are biocompatible and osteoconductive material.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.3
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• pp.500-514
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• 1996

The purpose of this study was to observe the tissue response in applying staples and various suture materials to both scalp and buccal mucosa in rabbits. 18 rabbits were divided into 6 groups. The incised wounds of both scalp and buccal mucosa were sutured with staples, polyglactin 910, chromic catgut, mer silk and nylon. The experimental animals were sacrificed after 1, 3, 5, 7, 10, 14 days posto peratively 3 animals at one time. The tissue was stained with Hematoxylin and eosin, and Masson's Trichrom. In light microscopic examinations, the sutured sites were examined histologi cally according to 6 degrees about inflammation and collagen deposit. The results were obtained as follows, 1. The chromic catgut, an absorbable suture material, was absorbed by 7 days, whereas polyglactin 910 and mersilk began to get absorbed after 7 days. 2. Mersilk manifested a broad range of inflammation in the scalp, and both staple and nylon showed a severe inflammatory reaction in the buccal mucosa. 3. With polyglactin 910, both tissue samples showed only minor foreign body reaction, however in the scalp, the process of fibrosis took place compara tively slowly, whereas in the buccal mucosa, it occurred promptly and manifested active fibrosis by 7 days. 4. Mersilk showed widespread a matrix formation in both scalp and buccal mucosa, and showed the most severe inflammatory reaction by 3 days, which did not seem to decrease even after 7 days. 5. Both staple and nylon showed relatively a severe inflammatory reaction, however fibrosis took place rather promptly compared to the other groups. 6. Generally, in the buccal mucosa fibrosis occurred more promptly than in the scalp in both control and experimental groups. 7. Retention of the suture material and stability of the knot were the best with the staple, and better stability was manifested by the multi-stranded poly glactin 910 and mersilk than singlestranded chromic catgut and nylon. From above results, in the buccal mucosa absorbable suture materials especially polyglactin 910 showed better response in the aspect of inflammatory reaction, while in the scalp monofilament suture materials such as staple and nylon manifested a early fibrosis and collagen formation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.1
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• pp.2-8
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• 2012

Introduction: Auto-tooth bone graft material consists of 55% inorganic hydroxyapatite (HA) and 45% organic substances. Inorganic HA possesses properties of bone in terms of the combining and dissociating of calcium and phosphate. The organic substances include bone morphogenetic protein and proteins which have osteoinduction capacity, as well as the type I collagen identical to that found in alveolar bone. Auto-tooth bone graft material is useful as it supports excellent bone regeneration capacity and minimizes the possibility of foreign body reaction,genetic diseases and disease transmission. Materials and Methods: Implant placement combined with osteoinductive regeneration,preservation of extraction socket, maxillary sinus augmentation, and ridge augmentation using block type,powder type, and block+powder type autobone graft materialwere performed for 250 patients with alveolar bone defect and who visited the Department of Oral and Maxillofacial Surgery, College of Dentistry, Dankook University from September 2009 to August 2011. Results: Clinical assessment: Among the 250 patients of auto-tooth bone graft, clinical assessment was performed for 133 cases of implant placement. The average initial stabilization of placed implants was 74 implant stability quotient (ISQ). Radiological assessment: The average loss of crestal bone in the mandible as measured 6 months on the average after the application of prosthesis load was 0.29 mm, ranging from 0 mm to 3.0 mm. Histological assessment: In the histological assessment, formation of new bone, densified lamellated bone, trabecular bones, osteoblast, and planting fixtures were investigated. Conclusion: Based on these results, we concluded that auto-tooth bone graft material should be researched further as a good bone graft material with osteoconduction and osteoinduction capacities to replace autogenous bone, which has many limitations.

• Journal of Veterinary Clinics
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• v.13 no.2
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• pp.184-194
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• 1996

A comparative study of three absorbable suture materials of chromic catgut, Dexon II (a polyglycolic acid suture with a polycaprolate coating system) and Coated Vicryl (a polyglactin 910 suture with a glycolide-lactide-calcium stearate coating system) was undertaken in terms of tensile strength, breaking elongation, appearances of the suture materials in the subcutaneous layer of rats and of tissue reaction in the intramuscular layer of rats. The initial tensile strength of chromic catgut and the tensile strength after 21 days were about 1.55 kg and 0.19 kg, respectively. Those of Dexon II were about 2.01 kg and 0. 20 kg, respectively. Those of Coated Vicryl were about 2.39 kg and 0.48 kg, respectively. Coated Vicryl showed the highest tensile strength among the three materials during the whole period. On the other hand, Dexon II showed the highest breaking elongation among the three materials during the first week. But the breaking elongation of Dexon II rapidly continuously decreased during the whole period. The appearances of the suture materials in the subcutaneous layer of rats showed that chromic catgut was the fastest among the three materials, whereas it formed comparatively much connective tissue. The intramuscular absorption rate and tissue reaction of Dexon II were similar to those of Coated Vicryl. The intramuscular absorption rate of these was fairly late when compared with chromic catgut. And the tissue reaction appearance of these showed the formation of a granuloma with foreign body giant cells, macrothages and epitheloid cells by the 28th day in the experimental period.

• Archives of Reconstructive Microsurgery
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• v.2 no.1
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• pp.77-81
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• 1993

Free tissue transplantation is commonly performed with the brilliant achievement in microsurgery and anticoagulants and antithrombotic agents have been prescribed in the procedures. However, there is no clean-cut indication as to which agents would be more effective in every steps and final consequences. Low molecular weight heparins inhibiting coagulation in plateletrich plasma and acting on the vascular endothelium have antithrombotic and fibrinolysis action. The experiment with rat groin free flap transplantation after 6-hour ischemia and injection of the low molecular weight heparin was performed and the results between the injection and non-injection group were analysed as follows, 1. Both of the 24-hour groups, vessel patency was not proportional to color change of the groin flap. 2. On the second day after anastomois, heparin-injection group showed intact intima, patent lumen without thrombus, and mild granulomatous inflammation around the suture material and control group with doubtful patency revealed intimal loss and thrombus formation. 3. On the 5th, 7th, and 9th postoperative day, heparin group was patent in anastomosis and showed acute inflammatory cells. 4. The 7th-week period, heparin-injection group showed intact flap color, patent lumen with intact intima and persistent foreign body granuloma.

• Journal of the Korean housing association
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• v.27 no.3
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• pp.39-46
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• 2016

On account of the increasing crime rates annually and the consequent rising anxiety, safety has become an important topic in the aspect of environmental formation to provide decent lives to urban dwellers. As a result, great emphasis has been placed in the importance of Crime Prevention through Environmental Design (CPTED), a design method which utilizes physical environmental design to prevent crime. The definition of CPTED encompasses the technological level of crime prevention as well as comprehensive environmental design which takes into consideration fear or terror in view of human recognition and emotion. However, the current application method of CPTED in Korea is still limited to the technical supplementation of facilities, such as CCTV and streetlight, and fragmental modification like village mural paintings. Moreover, the guideline for CPTED in Korea is only a theoretical adaptation of foreign books and does not offer sufficient studies for a practical design method that will improve the life of city dwellers. The purpose of this study is to examine design methods for safe environment construction in accordance with the changing concept of CPTED by understanding the characteristic of space and analyzing the how the methods of light are expressed. This study aims to provide basic material which will serve as a guideline in creating a safe environment in the future.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.249-262
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• 1997

The present study investigates the effects of calcium sulfate graft on the periodontal healing in intrabony periodontal defects of dogs. Following the general anesthesia with 30mg/kg pentobarbital injected intravenously, the first premolar was extracted and full-thickness periodontal flap was elevated from the second premolar to the fourth premolar. The portion of premolars coronal to the alveolar crest was removed and mesial and distal roots were separated. Exposed root canals were sealed with Caviton and covered completely with flaps sutured. Following the healing period of 12 weeks, the surgical sited were uncovered and $4{\times}4mm$ intrabony defects were surgically created. Those defects with calcium sulfate graft following the root planing was designated as the test sites and those with flap surgery-only were designated as control sites. The animals were sacrificed after 8 weeks and the healing was histologically analyzed. The results were as follows. 1. No foreign body reaction or inflammation were observed in either groups. Calcium sulfate was completely resorbed in the test sites. 2. New cementum was observed coronal to the notch in both groups. Connective tissue fibers were oriented parallel to the root surface in the controls. Connective tissues were formed in large amount in the sites. 3. Test sites showed marked amount of new bone formation while the control sites showed minimal bone gain. 4. Root resorption was observed in coronal portions of th control Sites. The results suggest that calcium sulfate is a biocompatible graft material with a potential for new bone and cementum formation.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.167-176
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• 2009

Purpose: The purpose of this study is to histologically and histomorphometrically evaluate the effect of PLGA on bone regeneration compared with bone graft material. Methods: The experimental study was conducted in 10 rabbits with 2 different healing periods of 2 and 4 weeks. Following surgical exposure of the calvarium, 4 circular bone defects with a diameter of 4.6mm were formed. Rabbits were divided into control group, test groups I, and II. 10 defects assigned to the test group Ⅰ were grafted with Nu-oss and other 10 defects assigned to the test group II were grafted with PLGA. The rest of the defects were in the negative control group. At 2nd and 4th week after surgery, 10 rabbits were sacrificed through intracardiac perfusion and then specimens were obtained. Histological analysis was performed following staining with trichorme and transversal sectioning of the calvarial bone. Results: A group which used PLGA showed tissue reactions characterized by severe inflammation, rather than distinctive new bone formation. Conclusions: The present experimental investigations have failed to prove any beneficial effects of PLGA. PLGA used in this study exhibited foreign body reactions and a less favorable pattern of new bone formation in comparison to control group. Conclusion: PLGA did not function as scaffold. Further investigations of many types of micro PLGA that could improve its potential in GBR procedures are needed.