• 치과방사선
• /
• 제28권1호
• /
• pp.245-259
• /
• 1998

Cellular transforming genes have been identified in a number of different tumor cell lines and tumor types. A significant number of these oncogenes belong to the ras gene family. The ras gene family consists of three closely related genes:H-ras, K-ras and N-ras which code for a related 21 kDa protein. Mutations in codon 12, 13 and 61 of one of the three ras genes convert these genes into acute oncogenes. The presence of H-ras gene mutations has important prognostic implications in various tumors. Each genomic DNA was isolated from tumors induced by implantation with DMBA, or by treatment with DMBA -implantation/irradiation. When genome DNA was transfected into NIH 3T3 cells and investigated by two-step PCR-RFLP, the fOllowing results were concluded: 1. Transformation foci developed in two groups when the genome DNA of two experimental groups were transfected into NIH 3T3 cells. 2. Transformation efficiency was 0.01-0.02 foci/㎍DNA in the experimental group with the DMBA-implantation, 0.01-0.03 foci/㎍lgDNA in the experimental group with the DMBA-implantation/irradiation according to results of transfection assay. 3. When the point mutation of H-ras gene was investigated by a two-step PCR-RFLP, there was 13.9％ (5/36) in the experimental group with the DMBA implantation, 15.4 ％ (6/39) in the experimental group with the DMBA -implantation/irradiation. 4. The point mutation in codon 12 and 61 of H-ras was 5.6％(2/36) and 8.3％(3/36) in the experimental group with the DMBA implantation. 5. The point mutation in codon 12 and 61 of H-ras gene was 7.7％(3/39) in the experimental group with the DMBA -implantation/irradiation.

• 한국과학교육학회지
• /
• 제29권8호
• /
• pp.848-860
• /
• 2009

이 연구에서는 개방적 참탐구 활동을 수행한 학생들의 탐구보고서에서 과학자들의 보고서 쓰기에서와 같은 특징이 나타나는지 살펴보고, 개방적 참탐구 활동 수행 후 실시한 학급 토론활동이 탐구보고서 쓰기에 미치는 효과에 대해서 알아보았다. 서울시 소재 과학고등학교 1학년 학생들을 대상으로 비교집단(전통적 학교탐구 수행, n=45), 실험집단 1(개방적 참탐구 활동 수행, n=43), 실험집단 2(개방적 참탐구 활동 수행 후 학급토론 실시, n=43)로 구분하여, 탐구를 수행하게 한 후 작성한 보고서를 분석하였다. 보고서 분석은 실험 결과에 대한 예상하기(근거제시 및 기술의 타당성), 데이터 해석하기(데이터전환 및 비판적 해석), 결론쓰기(실험결과에 기초한 객관적 진술)를 중심으로 이루어졌다. 그 결과 실험집단에서 과학자들의 보고서쓰기 특징이 나타나는 빈도가 비교집단보다 높게 나타났다. 특히 '근거를 제시하여 예상하기(p<.01)'와 '데이터에 대한 비판적인 평가(p<.05)'에서 유의미한 차이를 나타내었다. 그러나 결론쓰기에서는 세 집단 모두 실험결과에 기초하여 객관적으로 기술하는 빈도가 아주 낮게 나타났다. 보고서의 기술 내용면에서는, 실험집단에서 실험결과에 대한 예상이 훨씬 더 정교하게 기술되어 있었고, 데이터 전환의 정확성과 데이터에 대한 비판적 해석을 볼 수 있었다. 그리고 실험집단 2의 학생들의 보고서에서는 데이터에 대한 비판적 해석, 실험의 오차에 대한 기술을 볼 수 있었고, 이는 학급 토론활동이 학생들에게 과학적 사고를 하게 하는데 효과적임을 의미한다.

• 호남수학학술지
• /
• 제30권2호
• /
• pp.207-217
• /
• 2008

Digital geometry has strongly contributed to the study of a discrete topological space $X{\subset}{\mathbf{Z}}^n$ with k-adjacency of ${\mathbf{Z}}^n$. As a survey-type article, we review various utilities of digital geometry.

• 자연과학논문집
• /
• 제8권2호
• /
• pp.17-20
• /
• 1996

Fiber의 dimension이 일일 때, Equivariant Serre problem이 실 대수 범주에서 맞다는 것을 보였다. 즉 실 표현공간 위에서의 equivariant line bundle은 실 표현공간과 어떤 G-module의 product bundle과 동치임을 보였다.

• 호남수학학술지
• /
• 제39권1호
• /
• pp.101-113
• /
• 2017

Let G be a semialgebraic group which is not necessarily compact. Let X be a proper semialgebraic G-set whose orbit space has a semialgebraic structure. In this paper we prove that X has a finite open straight G-CW complex structure.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제15권3호
• /
• pp.229-243
• /
• 2008

This paper is intended to clarify and verify two representation algorithms computing representations of elements of free groups generated by two linear fractional transformations. Moreover in practice some parts of the two algorithms are modified for computational efficiency. In particular the justification of the algorithms has been rigorously done by showing how both algorithms work correctly and efficiently according to inputs with some properties of the two linear fractional transformations.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제11권3호
• /
• pp.29-36
• /
• 2007

Let T be an ergodic measure preserving transformation on (X, B, ${\mu}$). It is called 2-simple if every 2-fold ergodic joining is either a product measure or an off-diagonal measure. In general, factors of simple maps are not simple. So far, there has been no characterization of the factor of simple maps. In this paper, we give a joining characterization of factors of simple maps.

• 대한한방부인과학회지
• /
• 제22권3호
• /
• pp.36-50
• /
• 2009

Purpose: This study was to determine the protective effects of Dioscoreae Rhizoma on the Mouse Embrio Fibroblast (MEF) cells exposed to the ultraviolet rays(UVA). Methods: The samples were assigned randomly to five groups; control group without any treatments, UVA group exposed only to UVA, DR group exposed only to the Dioscoreae Rhizoma, UVA-DR group exposed to UVA before being treated with the Dioscoreae Rhizoma, and DR-UVA group treated with the Dioscoreae Rhizoma before being exposed to UVA. The survival rate of cells, metabolic rate of cells, transformation of nucleus within cells, alteration of cell cycle, effects on the apoptosis, the change of the amount of protein related to cell cycle were measured in order to determine the cell protective effects of the Dioscoreae Rhizoma on each group. Results: 1. DR-UVA group has more cell protective effects compared to the UVA group in all experiments, indicating that the Dioscoreae Rhizoma protects skin from UVA physically and chemically. 2. UVA-DR group shows more efficiency compared to UVA group in rapid recovery of damaged cell and leading highly damaged cells to apoptosis, preventing the expression of abnormal cells. Conclusions: Dioscoreae Rhizoma has effects of protecting MEF cells from UVA, of recovering cells damaged by UVA, and of prohibiting the expression of abnormal cells.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권9호
• /
• pp.4409-4412
• /
• 2012

Present study was undertaken to estimate and compare erythrocyte superoxide dismutase (E-SOD) and Glutathione peroxidase (GPx) levels in oral submucous fibrosis, oral leukoplakia and oral cancer patients and age/sex matched healthy subjects, 25 in each group. Statistically significant (P<0.001) decrease in E-SOD and GPx levels were observed in OSF, oral leukoplakia and oral cancer groups as compared to the control group. Oral leukoplakia group showed lower levels in comparison with OSF (P>0.05). Oral cancer group had the lowest levels amongst the study groups. Imbalance in antioxidant enzyme status may be considered as one of the factors responsible for the pathogenesis of cancer and may serve as a potential biomarker and therapeutic target to reduce the malignant transformation in oral premalignant lesions/conditions.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.563-564
• /
• 2014

Recent developments in the prediction of the contribution of windnoise to the interior SPL have opened a realm of new possibilities in terms of i) how the convective and acoustic sources terms can be identified, ii) how the interaction between the source terms and the side glass can be described and finally iii) how the transfer path from the sources to the interior of the vehicle can be modelled. This work discusses several simulation methods that can be used to represent the physical phenomena involved such as CFD, FEM, BEM, FE/SEA Coupled and SEA. This work focuses on the validation of the wind noise source characterization method and the vibro-acoustic models on which the wind noise sources are applied in the framework of a benchmark proposed by Hyundai Motors Corporation.