• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권4호
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• pp.278-286
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• 2011

Introduction: This study examined the predictability of new bone formation in the pneumatized maxillary sinus using only fibrin-rich blocks with concentrated growth factors as an alternative to bone grafts. Materials and Methods: Maxillary sinus augmentation was performed in thirty-three patients with a deficient alveolar bone height (mean 3.9 mm). All patients were treated consecutively with sinus membrane elevation via the lateral window approach and panoramic radiograms and cone-beam computed tomograms were taken to evaluate the remaining bone height and the new bone formation in the maxillary sinus, before and after surgery. Four biopsy specimens were taken at the time of implant consolidation (after an average of five months healing) and were stained by H & E and Trichrome staining. Results: None of the patients had postoperative complications during implant consolidation. After an average of 5 months since sinus augmentation, newly formed bone was observed in all cases by a radiographic evaluation. In 4 biopsy samples, newly formed bone was observed along the floor of the replaced bony window. The osteoblast lining and well distinguished Osteocytes in the lacunas were observed in the newly formed bone. Of the 74 implants (4 different surfaced implants - resorbable blast media-surfaced (RBM), Hydroxyapatite (HA) coated, acid-etched, sintered porous-surfaced implant) placed, one RBM implant failed. The success rate was 98.6% after a mean of 15 months. Discussion: These results suggest that maxillary sinus augmentation using fibrin rich block with concentrated growth factors is a successful and predictable technique.

• 치위생과학회지
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• 제12권6호
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• pp.689-695
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• 2012

The aim of this study was to elucidate the effects of concentrated growth factors (CGFs) on human gingival fibroblasts in vitro. Blood was collected from three male volunteers (average age 27 years). CGFs were prepared using standard protocols. The CGF exudates were collected at the following culture time points: 1, 7, 14, and 21 days. The levels of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor ${\beta}1$ (TGF-${\beta}1$) in CGFs were quantified. The CGF exudates were then used to culture human gingival fibroblasts. The biologic characteristics of these fibroblasts were analyzed in vitro for 21 days. Platelet-rich plasma released the highest amounts of TGF-${\beta}1$ and PDGF-BB on the first day. The level of TGF-${\beta}1$ had decreased slightly by day 7, although the difference compared to levels at day 1 was not statistically significant. However, by days 14 and 21, levels of TGF-${\beta}1$ had dropped significantly compared to day 1 levels. The levels of PDGF-BB at days 7, 14, and 21 did not differ significantly from that measured on day 1. CGFs maintained the release of autologous growth factors for a reasonable period of time (7 days for TGF-${\beta}1$ and 21 days for PDGF-BB). Gingival fibroblasts treated with CGF exudates collected at day 14 reached peak viability and synthesized type I collagen. Furthermore, the CGF exudates exerted positive effects on the proliferation and differentiation of these cells at days 1, 7, 14, and 21. The findings of this study suggest that treatment with CGFs represents a promising method of enhancing mucosal healing following surgical procedures.

• Archives of Plastic Surgery
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• 제40권5호
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• pp.530-535
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• 2013

Background Platelet-rich plasma (PRP) has more concentrated platelets than normal plasma (approximately 150-400${\times}10^3$ cell/dL). Platelets excrete several growth factors and cytokines that are associated with the healing and regeneration process. However, even though PRP is widely used, the mechanism or actual effect is presently unclear. Therefore, this study was performed to investigate the levels of growth factors and platelet concentration rate. Methods Autologous blood for preparing PRP was obtained from healthy subjects aged 25 to 35 years. The samples were divided into 4 experimental groups (inactivated whole blood, inactivated PRP, activated whole blood with thrombin and calcium chloride, and activated PRP). The platelet counts in the blood were analyzed and the growth factors were quantitatively measured. A statistical analysis was performed by using Dunn's multiple comparison test. Results In the blood cell analysis, the platelet count of the PRP group was approximately 4.25 times higher than that of the whole blood group. In the quantitative analysis of growth factors, the platelet-derived growth factor (PDGF)-AB, PDGF-BB, and transforming growth factor-${\beta}$ of the inactivated and activated PRP groups were higher than those of the inactivated and activated whole blood groups (P<0.05). Conclusions In this study, the platelet count and the levels of PDGF-AB and PDGF-BB in the PRP were determined. Further, more research is required on the bioactivity level of the growth factors secreted during the process of PRP preparation and the potency of growth factors that can be exerted physiologically in vivo.

• 한국항만경제학회지
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• 제28권1호
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• pp.123-142
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• 2012

최근의 항만개발은 종합 국제물류서비스의 집합체로서, 국제물류기능, 산업경쟁력 확보를 위한 종합산업기지화, 자체 물동량 창출을 위한 경제유발 종합기지화, 지역경제 활성화를 기할 수 있는 부가가치항만, 친수 공간 확보 및 문화 활동의 복합기능화 등을 기할 수 있는 형태로 이루어지고 있다. 즉 국제분업화 및 SCM체제의 확산은 국제물류의 급격한 발전을 가져왔지만, 이에 대응하기 위해서는 항만을 중심으로 무역활동의 플랫폼을 구축하고, 대규모 항만배후부지를 개발하여 국제물류기지화를 기하여야 하는 새로운 부가가치 창출 노력이 있어야한다. 이러한 측면에서 부산항 신항과 BJFEZ 연계발전 방안을 "주관적인 요인", "산업환경적인 요인", "정부정책적인 요인" 세 가지로 대분류하여 분석한 결과는 "주관적인 요인"이 4.11점, "산업환경적인 요인"이 3.92점, 그리고 "정부정책적인 요인"이 4.01점이었다. 따라서 부산항 신항 및 BJFEZ의 연계발전을 위한 가장 근본적인 요인은 부산항 신항 및 BJFEZ의 연계발전 모델 정립을 통한 경쟁력 확보, 집중화된 시장전략 및 친시장적인 능력, 신속한 고객욕구 충족 및 신뢰성 확보 등 주관적인 연계발전 요인으로, 산업환경적인 요인이나 정부정책적인 요인 보다 월등히 앞서는 평균평점을 기록하였다. 그 다음 순위는 산업환경적인 요인(3.92점) 보다 정부정책적인 요인(4.01)이 더 높은 점수를 기록하고 있는데, 이것은 항만 및 경제자유구역의 개발과 발전은 공공성과 인프라 성격이 큰 분야로서 국가정부의 정책적인 배려없이는 올바른 발전을 기약하기 힘들다는 것을 나타낸 것이다.

• 한국항만경제학회지
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• 제31권1호
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• pp.51-68
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• 2015

최근 우리나라에서도 '해양경제특구'의 지정 필요성이 대두되고 있다. 해양은 새로운 자원 확보 및 국가적 역량제고에 무한한 가능성의 공간을 제공하며, 특히 중국, 일본 등 동북아 주변국의 국가 차원의 해양산업 발전전략을 강화하고 있으나 국내 항만정책은 그간 양적성장 위주로 추진되어와 발전한계에 봉착하고 있다. 따라서 국가적 차원의 해양산업 고도화 및 고부가가치 창출 전략 필요한 시점에 와 있으며, 이에 '해양경제특구'의 지정 필요성이 크게 대두되고 있다. 그러나 '해양경제특구'의 지정이 중요한 것이 아니라 그 성공적인 개발을 통한 시너지 효과의 극대화가 중요한 것이다. 따라서 본 논문에서는 '해양경제특구'를 지정하여 성공적으로 개발하기 위한 성공 요인분석을 하였다. '해양경제특구'의 성공적인 발전 요인 중 대분류 세 가지 요인에 대한 분석결과는 "주관적인 요인"이 4.11점, "산업환경적인 요인"이 3.89점, 그리고 "정부정책적인 요인"이 3.72점이었다. 세 가지 요인 중 주관적인 요인의 평균평점이 월등히 높아 결국 '해양경제특구'의 성공적인 발전을 위해서는 입주기업 스스로가 집중화된 시장전략 및 친시장 능력을 확보하여 경쟁력을 갖추는 것이 가장 중요하다는 것을 나타내고 있다. 하지만 산업환경적인 요인과 정부정책적인 요인의 평균평점은 각각 3.89점 및 3.72점을 기록하여 주관적인 요인보다는 적은 영향을 미치고 있다는 결론이다. 즉, 주관적인 요인의 평균평점이 월등히 높다는 것은, '해양경제특구'의 성공적인 발전을 위해서는 입주업체 스스로가 가장 우선적으로 (1) 집중화된 시장전략 및 친시장적인 능력을 확보하고, (2) 신속한 고객 욕구 충족 및 신뢰성을 확보하며, (3) 특구 내 해양산업 분야 간 연계발전 모델 정립을 통한 경쟁력 확보하는 것이 가장 중요하다는 것을 의미한다.

• 한국안전학회지
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• 제14권4호
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• pp.28-36
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• 1999

In this paper, A circular arc crackered plate in biaxially stretched sheets was investigated in the boundary element method. The applications of fracture mechanics have traditionally concentrated on crack problems under an mode I, straight crack. However, many service failures occur from growth of cracks subjected to mixed mode loadings. A rectangular plate with arc crack or slanted central crack, under biaxial tensile loading, was treated analytically and also solved numerically. The Results from BEM applying different loading conditions, crack length (a/W), arc angle($\alpha$) are presented and discussed. The stress intensity factors are evaluated by the techniques of the J-integral. The decomposition method, used to decouple the stress intensity factors in mixed mode problems, is implemented by a considering a small circular contour path around each crack tip. The BIE method was successfully applied to a circular arc crackerd plate problem, also slanted centre cracked plate under mixed mode.

• 한국항만경제학회지
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• 제17권2호
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• pp.61-87
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• 2001

The purpose of this paper is to analyze the location, population growth. and cargo concentration of Korean port-cities. In the location theory, Sommer (1976) and McGee (1967) models are newly introduced, as are the Rimmer (1967), Bird (1965), Hoyle (1981) models. which were already introduced in previous studies from Korea. Analysis of population growth in the Korean port-cities is conducted using data from 1966 to 1998. Rimmer and Hoyle's concentration models are used to measure cargo concentration from 1966 to 2000. The main results of this paper are as follows: First, Korean ports are concentrated on the East Sea, the Southern Sea, and the West Sea. Their locations are closely related with the hinterland. the inland city, and growth of port-cities. In considering the foreign countrys' cases, Korean port-cities are similar to the models of Bird and Hoyle. Second, the populations of Ulsan and Pohang grew at the fastest rate in 1966-1998, while the port cities in the Honam and Jeiu region grew at much lower ratios. Most port cities are located near large industrial complexes. Third the growth rates of Gwangyang, Daesan, Pohang, Pyungtaeg, and Samchunpo increased, while those of Busan. Mukho, Masan, Mogpo, Yeosu, and Sokcho declined. Of particular note, the growth rate of Busan remained negative after the late 1980s. Fourth. empirical results using the Rimmer (1967) model indicate that Gwangyang, Daesan, Pyungtag, and Pohang have shown the concentration. But the deconcentration was shown from the Busan, Mukho, Janghang, Gunsan, Mogpo, Yeosu, Masan, Sokcho. and Jeju. Fifth, the concentration of ports located in West coast region has shown the mixed results between concentration and deconcentration except the concentration of early 1970s and 1990s. The concentration of ports located in East coast region has shown the concentration before the middle of 1980s. And deconcentration after the middle of 1980s have appeared. The Southern coast region has shown the continuous deconcentration except the partial concentration of early 1986. and 1991. Planners of Korean ports should find out the factors of concentration and deconcentration of each ports and should determine factors such as investment priority level. size and scope in order to ensure the balanced development of regional ports and port-cities.

• 한국미생물·생명공학회지
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• 제17권3호
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• pp.231-235
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• 1989

부착성 동물세포인 recombinant human embryonic kidney cell line 293을 5% FBS가 함유된 DME/F12(3:1) mixture 배지에서 배양할 경우 static culture에서와는 달리 미립담체 배양에서는 낮은 부착효율과 spreading의 저해현상이 관찰되었다. Cell line 293의 미립담체 배양에 있어서 배지내의 serum은 세포의 미립담체에 대한 부착속도(attach-ment rate)를 감소시킬 분만 아니라 세포의 증식을 저해한다는 사실을 확인하였다. 이러한 경우, conditioned microcarrier를 이용함으로써 미립담체로부터 세포의 탈착을 어느 정도 막을 수 있었다. 특히 autocrine growth factor를 생성하는 hepatoma cell line인 HpG 2 cell을 배양하여 얻은 conditioned medium을 serum-free medium에 첨가하여 사용함으로써 세포의 정상적인 성장 분만 아니라 growth-stimulation을 유도할 수 있었다.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 2006년도 제28회 동계학술발표회 논문집
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• pp.226-247
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• 2006

Korea has accomplished remarkable economic growth based on the accumulating technological capability. Science and Technology policy aiming at quantitative growth has concentrated on S&T hardware infra-structure construction but it overemphasizes technological factors. This policy has not sufficiently reflected social and cultural elements that should be incorporated in S&T development process. Therefore many experts have been emphasizing the importance of science culture as an important ingredient of S&T policy. This paper aims at investigating how science culture could be diffused. Nowadays, many countries have a strong interest in science shop as an important instrument of science culture. Science shop, however, has been activated in European area so it is not familar to Korea. However there are already a few science shops in Korea. In this paper, we will investigate the Korea science shops. In particular, we will analyze the current status, organizational structure and problems of Korea science shops. we will draw some important policy implications to activate science shops and to strengthen S&T policies in Korea.

• 대한원격탐사학회지
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• 제36권5_4호
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• pp.1153-1166
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• 2020

본 연구는 위성영상 기반의 열 분포도 및 폭염을 심화시키는 요인 간의 공간적 상관성을 분석하여 열 집중지역과 향후 폭염 위험이 증가할 수 있는 공간의 탐색을 목적으로 수행되었다. 열 집중지역과 폭염 심화요인의 인구, 토지이용, 건축물 각각의 전역적 Moran's I는 높게 나타나 특정 공간에 집중하는 것으로 나타났다. 국지적 Moran's I 분석 결과로, 열 집중지역은 수도권 및 광역시 등 대도시에서 주로 나타났고 상대적으로 온도가 낮은 지역은 산림지역이 우세한 강원도 및 경상북도, 소백산맥 지역에서 집중적으로 나타났다. 인구증가율이 높은 지역은 서울 주변의 경기도, 대전, 부산 인근지역에서 군집 분포하였으며 토지이용과 건축물은 수도권과 대도시에 집중하는 유사한 공간 패턴을 보였다. Bivariate Local Moran's I 분석결과는 열이 집중된 지역에서 인구증가율이 높고, 인공적·도시적 건축환경 및 토지이용이 이루어지는 것으로 나타났다. 본 연구결과는 열 집중지역의 순위를 도출할 수 있으며 전국적으로 열이 집중되고 이를 심화시킬 수 있는 환경을 가진 지역을 탐색할 수 있으므로 궁극적으로 선제적 폭염 대응대책 수립에 기여할 수 있을 것이다.