• 폴리머
• /
• 제38권6호
• /
• pp.815-819
• /
• 2014

조직공학에서의 인공지지체는 세포의 부착과 증식 및 분화가 잘 되어야 하고, 우수한 생체친화성 및 생분해성을 지녀야 한다. 다양한 인공지지체 제작 방법이 시도되어지고 있으며, 최근들어 3D 프린팅 기술을 이용한 방식이 활발하게 연구되어지고 있다. 폴리카프로락톤(polycaprolactone, PCL)은 낮은 녹는점을 가지고 있어 3D 프린팅하기에 우수한 생체적합 고분자 합성재료이다. 본 연구에서는 3D 프린팅 기술을 이용하여 3차원 PCL 인공지지체를 제작하였고, 지지체의 표면개질을 위해 수산화나트륨(NaOH)을 이용하였다. 표면개질된 인공지지체의 표면특성을 SEM으로 확인한 결과, 수산화나트륨을 처리한 PCL 인공지지체가 처리하지 않은 PCL 인공지지체에 비해 거칠기가 증가함을 보였으며, 접촉각 측정을 통해 친수성이 증가함을 확인하였다. In vitro 실험결과, 수산화나트륨을 처리한 PCL 인공지지체가 처리하지 않은 PCL 인공지지체에 비해 세포의 증식과 분화가 증가함을 보였고, 세포의 부착 모습은 균일하고 밀집된 형태로 부착됨을 확인하였다. 따라서 조형가공기술을 이용하여 수산화나트륨을 처리한 표면개질된 PCL 인공지지체를 제작하고 분석함으로써, 세포적합성을 통해 체내 인공지지체 개발 적용 가능성을 제시하였다.

• 대한화장품학회지
• /
• 제36권2호
• /
• pp.137-143
• /
• 2010

유자(Citrus junos Sieb ex TANAKA)는 북동아시아 지역에서 재배되는 감귤류 종이며, 비타민 C, 플라보이드, 리모노이드를 풍부히 함유하고 있다. 한국에서 재배되는 유자는 차나 음식료품으로 사용되고, 부산물인 씨와 과피는 전량 폐기되고 있다. 이 연구에서는 유자 부산물을 기능성 화장품 소재로서 이용 가능성을 평가하였다. 씨와 과피 에탄올 추출물에서 DPPH (2,2-diphenyl-1-picrylhydrazyl) 라디칼 소거활성 효과는 크지 않았지만 고농도의 phenolic compounds를 함유하고 있다. 각질형성세포(HaCaT Keratinocyte)와 섬유아세포(Normal Fibroblast)에 UVB를 각각 12.5 $mJ/cm^2$, 15 $mJ/cm^2$를 조사한 후 항염효과와 Collagen 합성량, Collagen 분해효소인 MMP-1 (matrix metalloproteinase)의 발현량을 확인하였다. 과피 추출물에서 UVB에 의해 증가된 TNF-$\alpha$를 상당량 줄여주었다. 마찬가지로 과피 추출물은 MMP-1의 발현량을 줄여주고 Collagen의 합성량도 증가시켰다. 한편 유자 추출물의 $\alpha$-MSH (Melanocyte stimulating hormone) 처리에 의해 유도된 멜라닌 생합성 억제효능과 타이로시나제 발현량 감소를 확인하였다. 결론적으로 유자 부산물의 에탄올 추출물질은 항노화, 미백 기능성 화장품 소재로 가치가 기대된다.

• Journal of Gastric Cancer
• /
• 제15권1호
• /
• pp.46-52
• /
• 2015

Purpose: The aim of this study was to compare the short-term surgical and long-term functional outcomes of Billroth I, Billroth II, and Roux-en-Y reconstruction after laparoscopic distal gastrectomy. Materials and Methods: We retrospectively collected data from 697 patients who underwent laparoscopic distal gastrectomy for operable gastric cancer between January 2009 and December 2012. The patients were classified into three groups according to the reconstruction methods: Billroth I, Billroth II, and Roux-en-Y. The parameters evaluated included patient and tumor characteristics, operative details, and postoperative complications classified according to the Clavien-Dindo classification. Endoscopic findings of the remnant stomach were evaluated according to the residue, gastritis, bile (RGB) classification and the Los Angeles classification 1 year postoperatively. Results: Billroth I, Billroth II, and Roux-en-Y were performed in 165 (23.7%), 371 (53.2%), and 161 patients (23.1%), respectively. Operation time was significantly shorter ($173.4{\pm}44.7$ minute, P<0.001) as was time to first flatus ($2.8{\pm}0.8$ days, P=0.009), time to first soft diet was significantly faster ($4.3{\pm}1.0$ days, P<0.001), and postoperative hospital stay was significantly shorter ($7.7{\pm}4.0$ days, P=0.004) in Billroth I in comparison to the other methods. Postoperative complications higher than Clavien-Dindo grade III occurred in 61 patients (8.8%) with no statistically significant differences between groups (P=0.797). Endoscopic findings confirmed that gastric residue, gastritis, bile reflux, and reflux esophagitis were significantly lower in Roux-en-Y (P<0.001) patients. Conclusions: Roux-en-Y reconstruction after laparoscopic distal gastrectomy for middle-third gastric cancer is beneficial in terms of long-term functional outcome, whereas Billroth I reconstruction for distal-third gastric cancer has a superior short-term surgical outcome and postoperative weight change.

• Restorative Dentistry and Endodontics
• /
• 제26권1호
• /
• pp.77-85
• /
• 2001

The purpose of this in vitro study was to compare the apical leakage in extracted teeth filled with gutta-percha subsequent to dressing with one of three different calcium hydroxide preparations. Thirty six extracted teeth with single canal were used in this study. After working length determination, canals were prepared with K flexo files to a #40 at the working length. Step-back flaring was produced by using #45, #50 K flexo files and #2, #3, #4 Gates Glidden burs. The teeth were randomly divided into 3 groups of 10 each : the remaining six teeth were used for negative and positive leakage control: Group 1, dressed with pure calcium hydroxide powder (Sigma, USA) mixed with distilled water; Group 2, dressed with Metapaste (Metadent, Korea) ; Group 3, dressed with Vitapex (Neo Dental, Japan). Teeth were sealed with Caviton (GC, Japan) and incubated in 100% humidity, at 37$^{\circ}C$ for 1 wk. All kinds of calcium hydroxide were removed from the canal with a MAF and 5% NaOCl. The canals were filled with AH-26$^{\circledR}$ sealer and gutta-percha using lateral condensation technique, incubated in 100% humidity, at 37$^{\circ}C$ for 2 days for the sealer to be set. The teeth were coated twice with nail varnish except for an area of approximately 2mm surrounding the apical foramen. All specimens were placed in 2% methylene blue solution for 2 days. The root were sectioned longitudinally, the amount of apical leakage was measured to the most coronal part of the root canal to which the dye had penetrated. The independent measurements were made for each root using a stereomicroscope ($\times$40 magnification) and the average was recorded for statistical analysis. The results were as follows ; 1. The mean of apical leakage in group of pure calcium hydroxide ranged 0.102$\pm$0.156mm, in Metapaste$^{\circledR}$ ranged 0.062$\pm$0.069mm, and in Vitapex$^{\circledR}$ ranged 0.067$\pm$0.072mm. 2. Group of pure calcium hydroxide exhibited more leakage than those of 2 manufactured calcium hydroxide preparations, but it was not statistically significant. 3. Group of water-based Metapaste$^{\circledR}$ showed lesser leakage than that of oil-based Vitapex$^{\circledR}$, but it was not statistically significant.

• 한국조경학회지
• /
• 제34권1호
• /
• pp.92-106
• /
• 2006

The process of designing Cheonggyecheon Entrance Plaza began with researching four keywords: plaza, restoration. modernity and icon. The outcome of the research was reinterpreted into and informed the design. An urban plaza must not only be a stage for civic life but should also be a portrait of the city to which it belongs. Many Korean plazas, however, are treated as if they are parks. Yeouido Park, which was originally a vast urban void, and Seoul Plaza, recently paved with grass, are good example. The strong 'green myth' can hinder socio-political activities. Cheonggyecheon cannot be said to have been 'restored', since it is still disconnected from its origin and upper streams, and the water is circulated by electricity. So it is better understood as an artificial urban waterfront, rather than an ecologically restored stream. This fact might diminish its ecological value, but not its recreational one. The entrance plaza therefore should reflect that the new stream brings back an 'experience', not only water itself. At the same time, the catch phrase of this restoration project was 'post-modern'. The demolished Cheonggye Expressway represents the 'economy drive' of the 1970s, so the newly opened Cheonggyecheon serves as a perfect counterpart to it. But modernity in Korea is the spirit that made many of the good things, not only its shortcomings, we have now. And from the philosophy of this restoration project, we can see that it is still an ongoing attitude in a way. Remnant of Cheonggye Expressway can evoke our nostalgia for the era. There are plenty of symbols in Seoul, both as architecture and objects. But none of them provide citizens with experience, other than the experience of looking at them. Cheonggyecheon Entrance Plaza is a good place to serve as an icon for a dynamic Seoul. From the research, the designer concluded that this plaza should commemorate the incomparable horizontal experience of Cheonggyecheon and the old expressway, amid the vertical metropolis. The Pedestrian Sculpture, which people can stroll on and look out over Cheonggyecheon, is to be made of steel cladding with a core structure and represents the dynamism of the stream, Seoul and contemporary Korea. The choice of material and the steel structure are also ways of creating the icon. The Water Plaza, the space underneath the ramp, will accommodate people and their urban activities, providing an opportunity to play with water. The Waterblades will be a device for the dramatic beginning of the stream, simultaneously camouflaging ugly openings in the outlets. The Wall of Archaeology is to be made with pre-fab resin blocks, translucent enough so that people can see through any archaeological findings of the site. The strong water-resistant character of resin makes the wall steady throughout the flood season as well. Cheonggyecheon restoration project is an effort to combine contemporary urban demand with the once-existing physicality by evoking our nostalgia for it. The project itself shows many socio-political issues of present-day Korea. The entrance plaza design thus is focused on suggesting an icon for the metropolis, simultaneously celebrating the stream itself. Within this space, people will be exposed to a unique experience that any 'green myth' cannot offer.

• 대한지리학회지
• /
• 제41권4호
• /
• pp.404-417
• /
• 2006

한라산 만세동산의 표고 $1,595{\sim}l,645m$에 위치한 1차수 실험유역에서 관측한 수문자료와 인근 관측소의 기상자료를 토대로 물수지를 분석하여 한라산 아고산대의 수문순환 특성을 규명하였다. 실험유역은 주로 조면현무암으로 이루어진 면적 1.34ha의 소유역이며, 지표식생은 제주조릿대와 초본 군락이 우점하고 있다. 물수지 분석에는 2004년 4월 15일부터 9월 19일까지 157일에 걸쳐 20분 간격으로 관측한 강수량과 유량을 이용하였다. 실험유역은 해안 및 중산간지대의 저지보다 $1.6{\sim}3$배 많은 3,074mm의 강수량을 기록하였으며, 강수량의 27.6%에 해당하는 850mm가 유역 하류로 흘러나갔다 증발산량은 강수량의 14.2%를 차지하는 437mm에 지나지 않으며, 나머지 58.2%에 해당하는 1,790mm는 기반암을 통과하여 지하로 이동하였다. 실험유역은 지형성 강수가 자주 발생하는 아고산대에 위치하므로 강수량이 많고 강수강도가 크나 유출량은 강수량의 30%를 넘지 못한다. 반면에 침루량은 유출량의 2배에 달하는 강수량의 60% 정도를 차지하고 있다. 따라서 한반도의 화강암이나 편마암 유역과는 달리 물수지 요소 가운데 침루 비율이 높게 나타나는데, 이것은 토양 공극율이 높고 토층 하부에 투수성이 큰 현무암질 용암이 분포하는 제주도의 지질 특성과 관계가 있는 것으로 생각된다.

• 한국습지학회지
• /
• 제8권3호
• /
• pp.29-38
• /
• 2006

조간대 Digital Elevation Model (DEM)은 순수 학문적 분야, 연안역 관리, 수산활동, 해상안전, 군사적 목적은 물론 자연적 인위적 환경 변화가 심한 조간대의 지형변화를 파악하는데 활용될 수 있다. 본 연구에서는 서해안에서 가장 큰 규모인 강화도 남단 조간대를 대상으로 광학위성자료를 이용한 수륙경계선 방법과 마이크로파 위성자료를 이용한 위상간섭기법을 적용하여 조간대 DEM을 생성하였다. 광학 위성영상인 Landsat-5 TM과 Landsat-7 ETM+ 에 수륙경계선 방법을 적용하여 생성된 DEM은 조간대의 전체적인 지형 형태를 잘 나타내었으나, 그 정밀도가 다양한 조석 상태를 반영하는 수륙경계선들의 갯수에 의해 결정됨을 알 수 있었다. 마이크로파 위성영상인 ERS-1/2와 ENVISAT에 위상간섭기법을 적용하여 DEM을 생성한 결과, 하루간격의 ERS-1/2 tandem 간섭쌍을 이용하여 영종도 북단 일부 조간대에 대해 DEM 제작이 가능하였으나, 그 밖의 지역에서는 높은 지표잔존수 함량으로 인한 낮은 긴밀도로 인하여 DEM 제작이 어려웠다. 향후 우리나라 다목적위성-2호를 이용하여 단기간에 다양한 조위를 갖는 높은 공간해상도를 갖는 위성영상을 얻음으로 수륙경계선 방법에 의한 DEM 생성의 정밀도를 높이 수 있을 것이다. 또한 계획 중인 single-pass 마이크로파 위성자료를 이용한 조간대 DEM 제작을 위한 기술개발이 요구된다.

• 한국임상수의학회지
• /
• 제25권6호
• /
• pp.482-487
• /
• 2008

This study was performed to investigate the ophthalmic findings of the Korean traditional 'Sapsaree' dogs, and to provide ophthalmic references. Five hundred forty-seven Sapsaree dogs were randomly chosen without any criteria preference. Ophthalmic examination was performed bilaterally using ocular equipments, including slit-lamp biomicroscope, tonometer, direct and indirect ophthalmoscope. The obtained data for ophthalmic findings were analysis by the multivariate linear regression model to identify effects of sex, age and hair coat type. For congenital conditions, the incidence of persistent pupillary membrane (PPM) was the most common defect and there was present 8.8 % whereas for acquired ophthalmic diseases, cataract was the most commonly observed (3.7 %) in Sapsaree dog. Other frequent ocular finding included persistent hyaloid vessel remnant (PHVR, 6.2 %) in congenital conditions, and postinflammatory retinal degeneration (PIRD, 3.1 %) and corneal dystrophy (2.4 %) in acquired ophthalmic diseases. Only one significant effect was age of the Sapsaree for PIRD (P=0.040). There are no any significant effect for sex and hair coat types. This study will provide useful guidelines to clinicians and breeders for the basic ophthalmic information on this breed.

• 대한원격탐사학회지
• /
• 제26권5호
• /
• pp.497-510
• /
• 2010

이 연구에서는 토양의 유전상수 (dielectric constant) 표면의 거칠기 (surface roughness)와 지표면의 기하 (geometric) 등과 같은 다양한 물리적 요소들의 정보를 포함하고 있는 SAR (Synthetic Aperture Radar) 자료를 이용하여 강화도 갯벌의 표층 퇴적환경을 분석하였다. JERS-1, ENVISAT과 ALOS 위성의 다양한 SAR 자료로부터 레이더 후방산란계수 (backscattering coefficient)를 추출하여 각 퇴적환경 요소들과의 관계를 파악하고 시간변화에 따른 지표의 변화 정도를 알 수 있는 긴밀도 (coherence)를 추출하여 퇴적상과 비교하였다. SAR 영상으로부터 추출한 후방산란계수와 긴밀도를 이용한 강화도 갯벌 퇴적환경 특성을 분석한 결과 높은 긴밀도를 갖는 지역은 입도가 작은 펄이 많이 포함된 펄 퇴적상이며 긴밀도가 낮을수록 큰 입도가 많이 분포하는 지역임을 알 수 있었다. 강화도 갯벌은 다른 갯벌과는 달리 조류로가 많이 발달하여 썰물 시 수분함유량에 많은 영향을 주어 모래 퇴적상과 혼합 퇴적상은 갯벌의 노출시간이 증가함에 따라 토양 수분함유량이 감소하여 후방산란계수가 점차 감소한다. 그러나 펄 퇴적상에서는 지형 고도가 높아 해수의 많은 영향을 받지 않으며 조류로의 밀도가 높기 때문에 토양 수분함유량이 감소하지만 후방산란계수가 높게 나타났다. 또한 갯벌은 토양 수분함유량뿐만 아니라 표면에 남아있는 잔존수도 많아 강우량이 많은 날은 지표 잔존수가 증가하기 때문에 비교적 후방산란계수가 낮게 나타나는 경향을 보였다. 이 연구의 결과, 긴밀도, 후방산란계수와 각 퇴적환경 요소들의 상관관계를 알 수 있었으며, 향후 강화도 갯벌 퇴적환경의 공간적 분석을 위해 각각의 요소들이 미치는 영향에 대한 정량적인 연구가 필요할 것으로 판단된다.

• Annals of Surgical Treatment and Research
• /
• 제95권6호
• /
• pp.303-311
• /
• 2018

Purpose: OncoHepa test is a multigene expression profile test developed for assessment of hepatocellular carcinoma (HCC) prognosis. Multiplication of ${\alpha}$-FP, des-${\gamma}$-carboxy prothrombin (DCP) and tumor volume (TV) gives the ${\alpha}$-FP-DCP-volume (ADV) score, which is also developed for assessment of HCC prognosis. Methods: The predictive powers of OncoHepa test and ADV score were validated in 35 patients who underwent curative hepatic resection for naïve solitary HCCs ${\leq}5cm$. Results: Median tumor diameter was 3.0 cm. Tumor recurrence and patient survival rates were 28.6% and 100% at 1 year, 48.6% and 82.9% at 3 years, and 54.3% and 71.4% at 5 years, respectively. The site of first tumor recurrence was the remnant liver in 18, lung in 1, and the peritoneum in 1. All patients with HCC recurrence received locoregional treatment. OncoHepa test showed marginal prognostic significance for tumor recurrence and patient survival. ADV score at 4log also showed marginal prognostic difference with respect to tumor recurrence and patient survival. Combination of these 2 tests resulted in greater prognostic significance for both tumor recurrence (P = 0.046) and patient survival (P = 0.048). Conclusion: Both OncoHepa test and ADV score have considerably strong prognostic power, thus individual and combined findings of OncoHepa test and ADV score will be helpful to guide postresection surveillance in patients with solitary HCCs ${\leq}5cm$.