• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.365-372
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• 2004

1)고강도강 BOP 시험 결과 강종에 차이 없이 용접속도에 따라 유사한 비드 형상을 가지는 것으로 나타났다. 한편 1.2t 시험편의 적정 용접속도는 $4\~8m/min$으로 나타났다. 2) 용접속도가 빠를수록 비드폭은 작아지며, 경도값은 높게 나타났다. 그리고, 최고 경도값은 강의 성분(Ceq)에 비례하는 것으로 나타났음, 그 결과 TRIP80(Ceq=0.53)의 경우 최고 520Hv이상의 경도값을 가지고 있었다. 3) LDH test 결과 DP강의 모재대비 용접부의 성형성이 약 $90\%$ 정도로 나타났으며, TRIP 및 일반 고강도강은 약 $80\%$의 성형성을 갖는 것으로 확인되었다. 4) He을 보호가스로 사용시 기공의 형성은 크게 억제되었다. 그리고 Ar 사용시에는 기공 형성이 He에 비해 많이 형성되는 것으로 나타나 사용시 주의가 필요한 것으로 보인다. 기공 형성은 TRIP > 60C/45R > DP 순서로 나타나 DP강이 가장 좋은 레이저 용접성을 가지고 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권21호
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• pp.9459-9465
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• 2014

Background: Structural maintenance of chromosomes 4 (SMC-4) is a chromosomal ATPase which plays an important role in regulate chromosome assembly and segregation. However, the role of SMC-4 in the incidence of malignancies, especially colorectal cancer is still poorly understood. Materials and Methods: We here used quantitative PCR and Western blot analysis to examine SMC-4 mRNA and protein levels in primary colorectal cancer and paired normal colonic mucosa. SMC-4 clinicopathological significance was assessed by immunohistochemical staining in a tissue microarray (TMA) in which 118 cases of primary colorectal cancer were paired with noncancerous tissue. The biological function of SMC-4 knockdown was measured by CCK8 and plate colony formation assays. Fluorescence detection has been used to detect cell cycling and apoptosis. Results: SMC-4 expression was significantly higher in colorectal cancer and associated with T stage, N stage, AJCC stage and differentiation. Knockdown of SMC-4 expression significantly suppressed the proliferation of cancer cells and degraded its malignant degree. Conclusions: Our clinical and experimental data suggest that SMC-4 may contribute to the progression of colorectal carcinogenesis. Our study provides a new therapeutic target for colorectal cancer treatment.

• 대한지리학회지
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• 제45권3호
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• pp.414-429
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• 2010

이어도 영유권 분쟁에 있어서 인접국인 중국의 부당한 주장에 대해 한국으로서 정합적인 논리를 개발 설득함으로써 문제를 평화적으로 해결하는 데 본 연구의 목적이 있다. 이를 위해 먼저 이어도의 자연경관의 특징과 형성과정을 자연지리학으로 정리하고. 이를 토대로 중국의 견강부회적인 주장에 대해 구체적이고 객관적인 반박 논리를 개발한다. 지질 지형과 관련한 지질사를 봤을 때 이어도가 제주도의 부속암초라는 사실이 그대로 드러나고 있으며, 중국이 주장하는 인문학적 증거, 즉 $\ll$산해경$\gg$에 대한 중국측의 해석은 우려할 정도로 왜곡되고 있다. 뿐만 아니라 중국측이 주장하는 논리가 북해대륙붕사건에서 독일의 논리를 도입하고 있으나 중국은 대향국간과 인접국간의 경계획정을 혼동하고 있어 정합성이 전혀 없다고 해도 과언이 아니다. 본 연구 결과는 강단지리학에 관심을 갖도록 할 뿐만 아니라 나아가 국민을 계도하고 관계기관이 상대국과 협상할 때 주요자료와 이론으로 활용할 수 있다.

• 한국공간구조학회논문집
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• 제7권4호
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• pp.73-78
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• 2007

연약지반에서 측방 유동에 의해 주변 지반에 큰 변형을 일으키며 이로 인하여 말뚝기초에 손상을 입히게 된다. 이러한 경우 설치된 말뚝을 수동말뚝이라 하며 편재하중이 작용하게 되고 이로 인해 측방토압을 받게 되며 측방변위가 발생하여 상부구조물에 영향을 미치게 된다. 그러나 국내의 경우 이러한 말뚝과 교대 변위간의 관계에 대한 예측 및 메커니즘에 대한 연구가 부족한 실정이다. 본 연구에서는 교대이동에 대한 해석을 위해 입체, 판 및 프레임 요소를 복합적으로 해석할 수 있는 연성 3차원 유한요소해석 프로그램을 개발하였다. 개발된 연성해석 프로그램을 이용하여 연약지반상 형상비(두께-지름비, t/D비)를 변수로 한 교대강관파일의 변형특성을 명확히 하였다.

• 치과방사선
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• 제28권2호
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• pp.415-433
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• 1998

Digora system is an intraoral indirect digital radiography system utilizing storage phosphor image plate. It has wide dynamic range which allows it to decrease the patient s exposure time and may increase diagnostic ability through image processing (such as edge enhancement, grey scale conversion, brightness change, and contrast enhancement). And also, it can transmit and storage image information. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries between Conventional radiograph and Digora images(unenhanced image, brightness & contrast controlled image, and edge enhanced image). ROC(Receiver Operating Characteristic) analysis, paired t-tests, and F-tests were done for the statistical evaluation of detectability. The following results were acquired: 1. In Grade I lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.953, 0.933, 0.965, 0.978 (p>0.05). 2. In Grade II lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.969, 0.964, 0.988, 0.994. Among theses areas, there was just statistical significance between Diagnostic abilities of Digora edge enhanced image and Conventional radiograph (p<0.05). 3. In the Interobserver variability, the ROC curve areas of Digora edge enhanced image was lowermost in these areas, regardless of the Carious lesion depths. In conclusion, intraoral indirect digital system, Digora system, has the potential possibility as an alternative of Conventional radiograph in the diagnosis of proximal caries.

• 치과방사선
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• 제28권2호
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• pp.505-519
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• 1998

The occurrence of PVNS in the TMJ is very rare. We report a case of PVNS which was misdiagnosed as a parotid tumor at first. CT and conventional radiograph revealed a well defined mass demonstrating higher attenuation than adjacent soft tissue. Erosion and expansion of the cortical plate of the mandibular condyle and sclerotic change beneath the margin of the lesion were also shown. MRI demonstrated well defined mass of very low signal intensity on both Tl and T2-weighted images due to ferromagnetic effect of the high concentrated hemosiderin and clearly delineated the extent of the lesion. Histopathologic findings and characteristic appearance of the various imaging methods were described and the usefulness of these images for diagnosis and pretreatment evaluation of PVNS were also discussed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권1호
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• pp.23-27
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• 2010

The purpose of this study was to evaluate the reliability of 6-axis model surgery simulator (6AMSS) for orthognathic surgery. A rectangular parallelepiped plastic block was assembled to model-mounting plate of 6AMSS. Left-right (X), anterior-posterior (Y), up-down (Z) translation and pitching (${\phi}X$), rolling (${\phi}Y$) and yawing (${\phi}Z$) rotation was planned and performed using 6AMSS. The actual translation and rotation were measured with dial gauge and precisional protractor, respectively. Comparison between the planned and actual movements of plastic block for each variable were made using paired t- test. Statistical analysis for X, Y, Z, ${\phi}X$, ${\phi}Y$ and ${\phi}Z$ movement have shown no significant differences between planned and actual movement (P > 0.05). This indicate that model surgery performed with the aid of the 6AMSS is accurate in 3D translation and rotation. The 6AMSS is practically useful for accurate fabrication of surgical splint for orthognathic surgery.

• 대한치과보철학회지
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• 제44권5호
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• pp.574-583
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• 2006

Statement of problem : The use of permanent magnetics is increasing in implant dentistry. Purpose : This study is to know the effect of permanent magnetics on bone matrix formation of osteoblasts. Materials and methods : The konus abutment-shaped permanent magnetics were connected to the implant fixture, and placed on the culture plate. The osteoblast-like cell Mc3T3E1 were used for cell culture. As the control group, the implants were connected to titanium healing caps, and cultured in the same conditions of experimental group. After 3. 7, 14 days, cells were cultured, and we measured and compared the amount of collagen type I, osteocalcin, which is bone matrix protein by Western immunoblotting analysis. Results: As a result of Western immunoblotting analysis for estimating the amount of bone extracellular matrix, there was no difference between osteoblast of the experimental group and the control group during 3 and 7day-osteoblast culturing. However when cells were cultured for 14days, the amount of bone extracellular matrix was increased, on the experimental group. Conclusion: From these results, magnetic field of permanent magnetics might have effect on bone formation of osteoblast, especially at initial stage of implant placement. Therefore, their clinical application for implant or bone graft could be possible.

• BMB Reports
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• 제40권6호
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• pp.936-943
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• 2007

Previously it was reported that promoter of groES-groEL operon of Staphylococcus aureus is induced by various cellwall active antibiotics. In order to exploit the above promoter for identifying novel antistaphylococcal drugs, we have cloned the promoter containing region ($P_g$) of groES-groEL operon of S. aureus Newman and found that the above promoter is induced by sublethal concentrations of many antibiotics including cell-wall active antibiotics. A reporter S. aureus RN4220 strain (designated SAU006) was constructed by inserting the $P_g$-lacZ transcriptional fusion into its chromosome. Agarose-based assay developed with SAU006 shows that $P_g$ in single-copy is also induced distinctly by different classes of antibiotics. Data indicate that ciprofloxacin, rifampicin, ampicillin, and cephalothin are strong inducers, whereas, tetracycline, streptomycin and vancomycin induce the above promoter weakly. Sublethal concentrations of ciprofloxacin and ampicilin even have induced $P_g$ efficiently in microtiter plate grown SAU006. Additional studies show for the first time that above promoter is also induced weakly by arsenate salt and hydrogen peroxide. Taken together, we suggest that our simple and sensitive assay systems with SAU006 could be utilized for screening and detecting not only novel antistaphylococcal compounds but also different toxic chemicals.

• 대한기계학회논문집B
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• 제25권6호
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• pp.799-803
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• 2001

Miniature heat pipe(MHP) with woven-wired wick was used to cool the CPU of a notebook PC. The pipe with circular cross-section was pressed and bent for packaging the MHP into a notebook PC with very limited compact packaging space. A cross-sectional area of the pipe is reduced about 30% as the MHP with 4mm diameter is pressed to 2mm thickness. In the present study a performance test has been performed in order to review varying of operating performance according to pressed thickness variation and heat dissipation capacity of MHP cooling module that is packaged on a notebook PC. New wick type was considered for overcoming low heat transfer limit when MHP is pressed to thin-plate. The limiting thickness or pressing is shown to be within the range of 2mm∼2.5mm through the performance test with varying the pressing thickness. When the wall thickness of 0.4mm is reduced to 0.25mm for minimizing conductive thermal resistance through the wall of heat pipe, heat transfer limit and thermal resistance of MHP were improved about 10%. In the meantime, it is shown that the thermal resistance and heat transfer limit for the MHP with central wick type are higher than those of MHP with existing wick types. The results of performance test for MHP cooling modules with woven-wired wick to cool a notebook PC shows the stability as cooling system since T(sub)j(Temperature of Processor Junction) satisfy a demand condition of 0∼100$\^{C}$ under 11.5W of CPU heat.