• 한국문화재보존과학회:학술대회논문집
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• 한국문화재보존과학회 2004년도 제20회 발표논문집
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• pp.81-91
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• 2004

The host rock of standing sculptured Buddha in the Yongamsa temple was macular biotite granite, which has gone through mechanical and chemical weathering. The principal rock-forming minerals are quartz, plagioclase, alkali feldspar, and biotite, the last two of which have been transformed into clay minerals and chlorite due to weathering processes. The bed rock around the Buddha statue is busily scattered with steep inclinations that are almost vertical and discontinuous planes with the strikes of $N8^{\circ}E$. The major joints have the strikes of N4 to $52^{\circ}W$ and N6 to $88^{\circ}E$ and the dips of 42 to $89^{\circ}$. Especially thee development of the joints that cross the major joints causes tile structural instability of the rock. The host rock of the Buddha image is separated into many different rock masses because of the also many different discontinuity, which group accounts for about $12{\%}$ of the rock. Thus it's estimated that the bed rock has not only plane and toppling failure but also wedge failure in all the sides. Since the earth pressure and the inclination pressure are imposed on the body of the Buddha in the basement rock, it's urgent to give a treatment of geotechnical engineering for the sake of its structural stability. The parts where serious fractures are seen should receive the hardening process using the fillers for stones. It's also necessary to introduce a landfill liner system in order to reduce the ground humidity. The rock surface of the Buddha statue are partly contaminated by lichens and bryophyte. The joints have turned into earth, which promotes the growth of weeds and plant roots. Thus biochemical treatments should also be considered to get rid of the vegetation along the discontinuous planes and prevent further biological damages.

• 대한소아치과학회지
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• 제27권3호
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• pp.444-456
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• 2000

치아 교환시기에 발거된 치관이 건전한 유구치 상아질 표면을 One-Bottle 상아질 결합제인 Primer & Bond NT(DeTrey/Dentsply, Konstanz, Germany)와 Single Bond(3M Co. U.S.A.) 그리고 대조군으로 Scotchbond Multipurpose System(3M Co. U.S.A.)를 이용하여 각 제조자의 지침에 따라 처리하여 레진을 충전하고 광중합하였다. 1. 전단 결합 강도의 측정결과 Primer & Bond NT군인 1군, Single Bond군인 2군, 그리고 대조군으로 사용된Scotchbond Multipurpose System군인 3군의 순서로 1군에서 다소 높은 전단 결합 강도를 보였으나, 모든 군들간에는 통계적 유의차가 없었다(p>.05). 2. 주사 전자현미경 소견에서 1군 2군에서 서로 유사한 양상의 잘 형성된 혼화층이 관찰되었으며, 레진 테그와 측방 가지 또한 다수 관찰되었다. 반면 3군에서는 혼화층이나 측방가지의 형성이 1, 2군에 비해 다소 미약한 양상을 보였다.

• 보존과학회지
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• 제28권1호
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• pp.39-52
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• 2012

일본 오이타현에 위치한 우스키 마애불상군은 12~14세기에 걸쳐 조성된 것으로 알려져 있으며 총 60여개의 석불군으로 이루어진 일본의 대표적인 석조문화재이다. 이 불상군을 이루는 기반암은 아소-4 화산쇄설암 층군에 포함되는 암회색 응회암이다. 이 석불군의 호키 I군과 후루조노를 대상으로 훼손지도를 작성한 결과, 호키 I군에서는 균열 약 121개, 염풍화로 인한 박락 19%, 흑색변색 5%, 생물학적 훼손 51%로 나타났고, 후루조노는 균열 약 48개, 염풍화로 인한 박락 24%, 생물학적 훼손 41%로 산출되었다. 암반에 균열이 집중적으로 분포하는 호키 I군에서는 사면안정성 평가를 통해 전체적으로 평면, 전도 및 쐐기파괴의 가능성이 확인되었다. 또한 초음파속도 측정을 수행한 결과, 애염명왕(기반암)은 1,520~2,794(평균 2,298)m/s를 보였으며, 동종암석으로 교체된 아미타여래좌상의 대좌(신부재)는 3,242~4,141(평균 3,813)m/s로 측정되어, 이들은 약 1,600m/s의 물성차이를 보였다. 따라서 적용 가능한 범위 내에서 균열, 공동, 탈락, 마모 및 박리박락 부분에 대한 보존처리 및 보강이 우선적으로 시행되어야 할 것이다.

• Applied Microscopy
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• 제20권1호
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• pp.17-35
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• 1990

Effect of 5-hydroxytryptamine(5-HT, serotonin) and its precursor tryptophan on the cell proliferation of brain and somite parts of 4 day chick embryo in Dulbeco's modified essential medium was examined morphologically at cellular level. It was realized that the externally added 5-HT and/or tryptophan disturbed cell proliferation and severve necrosis occured. Electron micrograph showed that the development of cell organelles were greatly impaired. The activities of both acetylcholine esterase and $Mg^{2+}$ -dependent ATPase of the brain tissues of 5 day chick embryo, which received 1mg of tryptophan and/or 0.1mg of 5-HT at primitive streak stage after 24 hrs incubation of the fertilized egg, were much lower(about 20-25%) than those of control group. These results were supported by the electron micrographs of chemically treated cells. Control cells showed clear densed bands of acetylcholine esterase activity around nucleus and rough endoplasmic reticulum but tryptophan or 5-HT treated groups showed discontinued activity bands. In the case of $Mg^{2+}$-ATPase, the control groups showed clear continuous activity bands but tryptophan and/or 5-HT treated groups were discontinuous. From the previous and present studies, it seems that the intracelluar 5-HT level is very important for the cell proliferation and normal morphogenesis.

• Journal of Welding and Joining
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• 제26권5호
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• pp.79-89
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• 2008

With the increased use of surface textured steel sheet in body-in-white assembly, resistance spot weldability of these steels is considered to be an important subject. This study evaluated nugget formation and weldability by measuring dynamic resistance with various weld pressure, current, and weld time for steel sheet with two different surface roughnesses. The surface roughness for T-H steel ($R_{a}=1.70\;{\mu}m$) was higher than that for T-L steel ($R_{a}=1.33\;{\mu}m$), and resulted in increased contact resistance and heating for T-H steel spot welding. Therefore, at low weld current and weld cycle ranges, the T-H steel showed better weldability over the T-L steel. The evaluations of weld interface showed that the fusion zone in the T-H steel sheet was continuous in contrast to discontinuous fusion zone for T-L steel sheet at the same welding conditions. A comparison of dynamic resistance and tensile-shear strength (TSS) between T-H and T-L steel sheet suggested that high surface roughness provided larger heating at early cycle of welding and larger TSS.

• 한국산학기술학회논문지
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• 제12권9호
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• pp.3869-3877
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• 2011

본 연구의 주목적은 기술혁신 유형에 따라 신제품 개발조직의 시장지향성과 창조성이 신제품 성과에 미치는 영향관계를 분석해 보는 것이다. 이를 위해 관련 선행문헌에 대한 종합적인 고찰 결과를 토대로 신제품 개발조직의 시장지향성 및 신제품 창조성 특성으로서 총 다섯 가지 요인을 도출하였고, 이들 영향요인과 신제품 성과, 그리고 기술혁신 유형 변수를 포함한 연구모형을 구축하였다. 설문응답 대상은 기업의 신제품개발 담당자로 한정하였으며, 조사결과 136개 기업으로부터 자료가 수집되었다. 수집된 자료를 토대로 다중회귀분석을 통해 실증분석을 수행한 결과는 다음과 같다. 첫째, 시장지향성과 창조성의 각 요인은 신제품 성과에 긍정적인 영향을 미치는 중요인 특성요인으로 밝혀졌다. 둘째, 기술혁신 유형에 따른 신제품 성과 영향요인의 차이에 관한 분석을 수행한 결과, 연속적 혁신에서는 시장지향성 요인이, 불연속적 혁신에서는 창조성 요인이 상대적으로 높은 영향을 미치는 것으로 밝혀졌다. 이상의 연구결과를 토대로 논의와 시사점을 제공하였다.

• 한국간담췌외과학회지
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• 제27권2호
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• pp.180-188
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• 2023

Backgrounds/Aims: The present study looked at the role of radical surgery in gallbladder cancers (GBC) with limited metastatic disease. Methods: The retrospective observational study was conducted to screen the database from 1st January 2010 to 31st December 2019. Patients of GBC found to have low-volume metastatic disease upon surgical exploration were included. Results: Of the 1,040 patients operated for GBC, 234 patients had low-volume metastatic disease (microscopic disease in station 16b1 node or N2 disease isolated port-site metastases, or low burden peritoneal disease with deposits less than 1 cm, in adjacent omentum or adjacent diaphragm or Morrison's pouch or a solitary discontinuous liver metastasis in adjacent liver parenchyma) detected intraoperative. Of these, 62 patients underwent radical surgery for R-0 metastatic disease followed by systemic therapy, while the remaining 172 patients did not undergo radical surgery and were given palliative systemic chemotherapy. Patients who underwent radical surgery had significantly superior overall survival (19 months versus 12 months, p < 0.01) and superior progression-free survival (10 months versus 5 months, p < 0.01) when compared to the rest. This difference in survival was more significant amongst patients when operated on after neoadjuvant chemotherapy. Regression analysis showed that a sub-group of patients with incidental GBC with limited metastases showed more favorable outcomes with radical surgery. Conclusions: Authors suggest a possible role for radical treatment of advanced GBC with a limited metastatic burden. Neoadjuvant chemotherapy can be used for preferentially selecting patients of favorable disease biology for curative treatment.

• Journal of Periodontal and Implant Science
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• 제29권3호
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• pp.507-519
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• 1999

The ultimate objective of periodontal treatment is to stop disease progression and to regenerate destroyed periodontal tissues and thereby regain normal function. Growth factors are naturally found polypetides which stimulate many cellular activities pertaining to wound healing by acting as signal molecule in controlling cell movement, proliferation, and matrix production. Platelet derived growth factor (PDGF) is 28,000-35,000 Da molecular weight dimeric protein with 2 long positively charged polypeptide chains connected by sulfide bonds. The purpose of this study is to evaluate histologically the initial guided tissue regeneration in a periodontal defect f a beagle dog treated with a biodegradable membrane formed with polylactic acid (poly-L-lactic acid) and polyglycolic acid loaded with 200ng/$cm^2$ platelet derived growth factor. 2 beagle dogs were used in he experiment. $5mm{\times}6mm$ alveolar bone defect was formed in upper and lower canines and third premolars and a reference notch was placed. PDGF-BB non-containing membrane was used as control. Each defect was randomly assigned to the test roup or the control group. The dogs were sacrificed 3 weeks after membrane placement. Toluidine blue and multiple staining was done for histological analysis. In the 3 week specimen in the control group, no new one formation could be seen. Small amount f bone resorption below the notch could be seen. In the notch, loose connective tissue with infiltration of inflammatory cells could be seen. Also thin discontinuous new cementum could be seen and the membrane still retained its structure. Where PDGF-BB containing membrane was used, new bone formation could be seen in the notch at weeks and also continuous thin cementum could be seen. PDL cells were observed between new bone and new cementum and some were attached to bone and cementum. These results suggest that new bone and cementum formation seen when PDGF-BB loaded membrane was used was due to inhibition of downgrowth of epithelial cells and also due to continuous release of the growth factor. Further study on the resorption characteristics of the membrane nd the release characteristics of the PDGF-BB is necessary. Also, development of a membrane easier to use clinically is necessary.

• Tuberculosis and Respiratory Diseases
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• 제48권4호
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• pp.478-486
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• 2000

연구배경 : 급성폐손상에서 폐포대식세포는 초기에 일어나는 염증반응 뿐 아니라, 후기의 복구 및 섬유화 과정에 관여하는 중요한 세포로 형태, 기능면에서 특성이 다른 여러 세포군으로 구성되어져 있는 것으로 알려져 있다. 95% 이상의 고농도산소로 폐손상을 일으킨 쥐를 12시간군, 24시간군, 48시간군으로 나누어서 고농도 산소 투여시기에 따른 폐포대식세포의 숫적인 변화 및 아형군의 분포변화를 관찰하고, 이들 아형군세포의 형태학적인 차이를 통해서 고농도 산소에 의한 폐손상시에 관련되는 특정 아형세포군이 있는지를 알아보고 이러한 분포의 차이와 조직병리적인 변화를 비교 관찰하였다. 방 법 : Sprague-Dawley계 흰쥐를 대상으로 고농도 산소 투여 후 12시간, 24시간, 48시간 경과시의 폐포대식세포를 추출하여 아형세포군의 분포 및 형태 변화와 조직의 변화를 비교 관찰하였다. 결 과 : 1) 총 폐포대식세포는 정상군 $171.6{\pm}24.1({\times}10^5)$, 12시간군 $194.8{\pm}17.9$, 24시간군 $207.6{\pm}27.1$, 48시간군 $200.0{\pm}77.8$개로 초기 장시간까지는 증가하나 이후에는 유의한 차이를 보이지 않았다. 2) 광학현미경 관찰로 측정한 폐포간질의 두께는 정상군 $0.7{\pm}0.2{\mu}m$, 12시간군 $1.5{\pm}0.4{\mu}m$, 24시간군 $2.3{\pm}0.4{\mu}m$, 48시간군 $2.5{\pm}0.4{\mu}m$로 24시간까지는 시간에 따라서 증가하나 24시간 이후로 유의한 차이는 없었다. 3) 폐포대식세포 분포의 시간 경과에 따른 변화는 fraction 1과 fraction 2는 의미 있게 증가되었으며 fraction 3는 의미 있게 감소하였다. fraction 4는 감소되어지는 양상을 보이나 통계적인 의의는 없었다. 4) 고밀도군에서 주로 관찰되는 세포는 세포 및 핵의 모양이 불규칙적이며 크기가 작고 한쪽으로 치우쳐 있으며, pseudopod, electron dense inclusion의 수가 현저히 많이 관찰됐다. 반면 저밀도군에서 주로 관찰되는 세포는 크기가 크고 세포 및 핵이 둥근형태를 보였다. heterogenous, empty inclusion이 보다 많이 관찰되었고 전반적인 inclusion의 수도 증가했다. 결 론 : 이상의 결과로 고농도산소에 의한 폐손상에서 특정한 폐포대식세포아형군이 폐손상에 중요한 역할을 할 것으로 보여지며 추후 이들 세포군이 증가한 이유 및 기전과 이들 세포군의 기능 및 표현형등에 관한 연구가 계속되어야 할 것이다.

• 대한치과보철학회지
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• 제31권2호
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• pp.165-179
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• 1993

Dicor has not been prescribed routinely, in spite of many advantages, because of esthetic limitations by excessive translucency and external shading. In an attempt to solve these problems, the technique of veneering Dicor by aluminous poreclain has been used and recently Dicor Plus system was developed. The purpose of this study was to evaluate the compatibility between Dicor and several veneering porcelains by measuring the shear bond strength and observing the failure mode and interface appearance with SEM. Total 55 Dicor disks(10.0mm diam. X 3.0mm thickness) were fabricated by lost wax technique and divided into five groups of 11. Veneering porcelains such as Dicor Plus, Vitadur Alpha, Vitadur N, Vivodent, and Ceramco II were built up over the center of the treated Dicor surface using paper tube(5.0mm diam. X 4.0mm height) and fired according to the manufacturesr’instructions. A representative sample from each group was completely embedded in epoxy resin and crosssectioned, and remaining 50 samples were embedded in epoxy resin with the bonded area perpendicular to table base. The shear bond strengths were measured by applying the shear load parallel to Dicor surface close to the bonded area. Failure modes and interface appearances were observed using SEM at 15 and 1000 magnification respectively. The obtained results were as follows : 1. The mean shear bond strengths showed Dicor-Dicor Plus(10.53 MPa); Dicor-Vitadur Alpha(8.84 MPa); Dicor-Vitadur N(7.37 MPa); Dicor-Vivodent(4.28 MPa); Dicor-Ceramco II(0.89 MPa). 2. The shear bond strength of Dicor-CeramcoII was significantly decreased compared with Dicor-Dicor Plus(p<0.01), but had no significant difference compared with Dicor-Vivodent(p>0.01). 3. The shear bond strengths of Dicor-Vitadur Alpha and Dicor-Vitadur N were not significantly different compared with Dicor-Dicor Plus(p>0.01). 4. SEM examination of bond failure modes revealed that Dicor-Dicor plus, Dicor-Vitadur Alpha, Dicor-Vitadur N exhibited cohesive failure within Dicor and Dicor-Vivodent exhibited adhesive failure. And Dicor-Ceramco III exhibited adhesive failure and cohesive failure within CeramcoIII together. 5. SEM examination of interfaces revealed that Dicor-Dicor Plus exhibited the most tight contact and Dicor-Vitadur Alpha, Dicor-Vitadur N exhibited acceptible contacts. But Vivodent exhibited discontinuous gap and Ceramco II exhibited large continuous gap.