• 기술혁신학회지
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• 제15권2호
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• pp.369-399
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• 2012

목적: 본 연구는 보건의료분야 연구주제 중 암유전자 분야의 지식지도를 구축하고 국내외 연구주제 네트워크를 시계열적으로 비교 분석함에 의해 국내 연구동향을 파악하고 향후 암유전자 분야에서 활발하게 연구될 영역을 확인하고자 하였다. 방법: 자료는 PubMed 데이터베이스의 Medical Subject Headings(MeSH) 검색기능을 이용하여 'Oncogene'을 주제로 하는 논문을 추출하였고, 교신저자 소속이 한국인인 논문을 분리한 후 추출된 논문의 키워드를 대상으로 하였다. 분석방법은 사회네트워크 분석 기법 중 가중치가 부여된 연결정도 중심성을 적용하여 연구주제 네트워크를 구축하였으며, 이를 시기별로 나누어 연구주제 변화를 확인하였다. 결과: 암유전자의 경우 국내외 모두 'Genes, ras'와 'Apoptosis', 'Signal Transdction' 등이 연결정도 중심성이 가장 높은 키워드였으며, 시기별로는 국내외 모두 'antineoplastic Agents', 'Prognosis', 'Tumor Markers, Biological' 등 암유전자를 대상으로 치료 및 진단, 예후와 관련된 연구가 활발해졌다. 결론: 암유전자 연구주제 네트워크 분석 결과 시기별로 연구주제에 대한 일정한 흐름이 있었다. 따라서 다양한 연구주제 네트워크 분석으로 각 질환별 연구단계가 확인된다면 다음 단계의 연구진행을 예측할 수 있을 것이며 그에 따른 연구개발 지원을 위한 전략을 수립할 수 있을 것이다.

• Journal of Microbiology and Biotechnology
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• 제23권7호
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• pp.1031-1040
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• 2013

Candida albicans is a dimorphic fungus that commensally colonizes human mucosal surfaces. The aim of this study was to assess the role of different C. albicans morphologies in inducing pattern recognition receptors (PRRs) and cytokines in macrophages. Macrophages may respond to pathogen-associated molecular patterns via TLR2 and TLR4 by expressing cytokines. The hyphal transition of C. albicans was induced by 20% serum (S), RPMI-1640 (R), or $39^{\circ}C$ culture (H). Macrophages were then challenged with either yeast (Y) or different hyphae cultures of C. albicans, followed by RT-PCR and FACS analysis of PRRs expression. In addition, macrophages were stimulated with either yeast or different hyphae cultures of C. albicans used by RT-PCR and Bio-Plex analysis of cytokines production. Macrophages expressed high levels of TLR4 and dectin-1 after stimulation with Y cells. In contrast, stimulation with H or R cells strongly increased the expression of TLR2 and dectin-2. Stimulation with Y cells significantly enhanced the expression of IL-$1{\beta}$ and weakly increased the expression of IL-6 and IL-12. Stimulation with hyphal cells (S, R, and H) strongly increased IL-10 expression, but weakly reduced IL-$1{\beta}$ expression. The phagocytosis activity and NO production of macrophages were decreased upon treatment with hyphal cells compared with yeast, and depended on the length of hyphae. In summary, the yeast and hyphae forms of C. albicans resulted in an induction of different PRRs, with accompanying differences in immune cell cytokine profiles.

• International Journal of Oral Biology
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• 제36권3호
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• pp.135-141
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• 2011

Hertwig's epithelial root sheath (HERS) consists of bi-layered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelial-mesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the ${\beta}$-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.

• 한국결정학회지
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• 제8권2호
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• pp.75-80
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• 1997

PbMg1/3Mb2/3Oc(PMN)은 대표적인 완화형 강유전체로 완만형상전이 거동을 연구하는데 중요한 재료로 이용되고 있다. 본 연구에서는 양질의 PMN 단결정을 성장시킬수 있는 조건을 결정하고 미세구조를 관찰하고자 하였다. PMN 단결정을 융제법 중 자발핵생성법과 상단종자정법을 이용하여 성장하였다. PbO융제를 이용하여 2-5mm의 결정을 성장시켰고, MgO를 100% 이상 융제로 첨가하였을 때 PMN 결정만이 성장됨을 관찰하였다. Pbo-B2O3 융제를 이용하여 (001)면이 잘 발달한 결정을 얻을 수 있었다. PbO-B2O3 융제를 이용하여 상단종자정법에 의해 1cm이상의 큰 단결정을 성장하였다. 안정된 성장조건을 마련하기 위해서는 종자정의 회전속도와 냉각속도, 종자정의 방향 등의 변수를 최적화하기 위한 계속적인 실험이 필요하다. 박편으로 가공한 결정의 전자선 회절패턴을 통해 미소부위에서 Mg2+와 Nb5+가 1:1의 규칙배역을 하고 있음을 확인하였다.

• 동굴
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• 제78호
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• pp.17-22
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• 2007

The melting temperature and critical temperature (Tc) of $YBa_2Cu_3O_x$ with deferent content impurities of PbO and $BaPbO_3$ were studied. When the PbO was used as addition in $YBa_2Cu_3O_x$, although the melting point could be reduced, the superconductivity (the transition wide, ${\Delta}T_c$) became poor. From the XRD pattern of the sintered mixture of $YBa_2Cu_3O_x$ and PbO it was known that there is a reaction between $YBa_2Cu_3O_x$ and PbO, and the product is $BaPbO_3$. In the process of the reaction the superconducting phase of $YBa_2Cu_3O_x$ was decreased and in the sample $BaPbO_3$ became the main phase. Therefore the superconductivity was reduced. $BaPbO_3$ was chosen as the impurity for the comparative study. The single phase $BaPbO_3$ was synthesized by the simple way from both mixtures of $BaCO_3$ and PbO, $BaCO_3$ and $PbO_2$. Deferent contents of $BaPbO_3$ (10%, 20%, 30%) were added in the $YBa_2Cu_3O_x$. By the phase analysis in the XRD patterns it was proved that there were not reactions between $YBa_2Cu_3O_x$ and $BaPbO_3$. When $BaPbO_3$ was used as impurity in $YBa_2Cu_3O_x$ the superconductivity was much better than PbO as impurity in $YBa_2Cu_3O_x$. But the melting point of $YBa_2Cu_3O_x$ with $BaPbO_3$ could not be found when the temperature was lower than $1000^{\circ}C$ in the DTA measurement.

• 대한조선학회지
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• 제22권1호
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• pp.21-30
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• 1985

This paper deals whth the buckling as well as postbuckling analysis of axisymmertric shells taking the initial deflection effects into account. Incremental equilibrium equations, based on the principle of virtual work, were derived by the finite element method, the successive step-by-step Newton-Raphson iterative technique was adopted. To define the transition pattern of postbuckling behavior from the prebuckling state more accurately, a simple solution method was developed, i.e. the critical load was calculated by the load extrapolation method with the determinant of tangent stiffness matrix and the equilibrium configuration in the immediate postbuckling stage was obtained by perturbation scheme and eigenvalue analysis. Degenerated isoparametric shell elements were used to analyse the axisymmetric shell of revolution. And by the method developed in this paper, the computer program applicable to the nonlinear analysis of both thin and moderately thick shells was constructed. To verify the capabilities and accuracies of the present solution method, the computed results were compared with the results of analytical solutions. These results coincided fairly well in both the small deflection and large deflection ranges. Various numerical analyses were done to show the effect of initial deflection and shape of shells on buckling load and postbuckling behavior. Futhermore, corrected directions of applied loads at every increment steps were used to determine the actual effects of large deflection in non-conservative load systems such as hydrostatic pressure load. The following conclusions can be obtained. (1) The method described in this paper was found to be both economic and effective in calculating buckling load and postbuckling behavior of shell structure. (2) Buckling and postbuckling behavior of spherical caps is critically dependent upon their geometric configuration, i.e. the shape of spherical cap and quantities of the initial deflection. (3) In the analysis of large deflection problems of shells by the incremental method, corrections of the applied load directions are needed at every incremental step to compensate the follower force effects.

• 한국통신학회논문지
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• 제38B권10호
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• pp.808-816
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• 2013

최근 들어 우리나라는 제조업 부문의 투자와 고용이 부진하여 잠재성장률이 둔화되는 가운데 신성장동력 및 일자리 창출부문으로서 지식서비스의 역할에 대한 관심이 고조되고 있다. 본 연구에서는 산출 및 고용측면에서 1995년에서 2010년까지의 기간 동안 우리나라의 지식서비스산업의 구조변화 양상을 분석함으로써 지식서비스산업이 경제성장 및 고용창출에 어느 정도의 기여를 하고 있는지를 살펴보고 지식서비스산업 육성을 위한 정책방향을 제시하였다. 지식서비스산업은 여타 산업에 비하여 총산출과 고용의 규모면에 있어서 국가전체에서 차지하는 비중은 그다지 크지 않지만, 타 산업에 비하여 가장 빠른 성장 속도를 보이고 있어서 우리나라의 총산출 증가와 고용 창출에 큰 기여를 한 것으로 나타났다. 하지만 산출증가율과 성장기여도는 점차 하락하고 있어서 지식서비스가 앞으로도 지속적으로 성장동력 및 고용창출에 기여하기 위해서는 생산성 증대를 위한 특별 대책이 요구된다.

• Transactions on Electrical and Electronic Materials
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• 제3권3호
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• pp.21-24
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• 2002

Two kinds of $Nd_{1+X}Ba_{2-X}Cu_3O_{7-{\delta}}$, the sintering samples and zone melting samples, were heat-treated under pure Ar at 950$^{circ}C$. The substitution of Nd ion for Ba ion in the $Nd_{1+X}Ba_{2-X}Cu_3O_{7-{\delta}}$ before and after the heat treatment was investigated by XRD. In order to confirm the effects of the heat treatment, the Tc and Jc of samples with/without the heat treatment under Ar were comparatively studied. $Nd_{1+X}Ba_{2-X}Cu_3O_{7-{\delta}}$ samples were oxygenated under pure oxygen at $300^{circ}C$. From the XRD pattern it was found that the sample with x<0.4 was transferred from tetragonal phase to orthorhombic phase after the oxygenation, while the sample with x>0.4 did not show the phase transition even after a long time oxygenation. Therefore, the low oxygen partial pressure (Ar+1 % O$_2$) was used for the ambient atmosphere of the zone-melting samples, which could reduce the melting temperature and depress the substitution of Nd for Ba. After the improvement in the zone-melting process, the Jc value was increased to 2 x $10^4$A/$cm^2$ (0 T, 78 K). The particle orientation and the structure of zone-melted NdBaCuO were studied by the XRD and SEM analysis.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
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• pp.57-59
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• 2004

The melting temperature and critical temperature (Tc) of YBa$_2$Cu$_3$Ox with deferent content impurities of PbO and BaPbO$_3$ were studied. When the PbO was used as addition in YBa$_2$Cu$_3$Ox, although the melting point could be reduced, the superconductivity (the transition wide, ΔTc) became poor. From the XRD pattern of the sintered mixture of YBa$_2$Cu$_3$Ox and PbO it was known that there is a reaction between YBa$_2$Cu$_3$Ox and PbO, and the product is BaPbO$_3$. In the process of the reaction the superconducting phase of YBa$_2$Cu$_3$Ox was decreased and in the sample BaPbO$_3$became the main phase. Therefore the superconductivity was reduced. BaPbO$_3$was chosen as the impurity for the comparative study. The single phase BaPbO$_3$was synthesized by the simple way from both mixtures of BaPbO$_3$and PbO, BaPbO$_3$and PbO$_2$. Deferent contents of BaPbO$_3$(10%, 20%, 30%) were added in the YBa$_2$Cu$_3$Ox. By the phase analysis in the XRD patterns it was proved that there were not reactions between YBa$_2$Cu$_3$Ox and BaPbO$_3$. When BaPbO$_3$was used as impurity in YBa$_2$Cu$_3$Ox the superconductivity was much better than PbO as impurity in YBa$_2$Cu$_3$Ox But the melting point of YBa$_2$Cu$_3$Ox with BaPbO$_3$could not be found when the temperature was lower than 1000 $^{\circ}C$ in the DTA measurement.

• Nuclear Engineering and Technology
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• 제35권4호
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• pp.318-335
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• 2003

Expert judgment is frequently employed in the search for the solution to various engineering and decision-making problems where relevant data is not sufficient or where there is little consensus as to the correct models to apply. When expert judgments are required to solve the underlying problem, our main concern is how to formally derive their technical expertise and their personal degree of familiarity about the related questions. Formal methods for gathering judgments from experts and assessing the effects of the judgments on the results of the analysis have been developed in a variety of ways. The most important interest of such methods is to establish the robustness of an expert's knowledge upon which the elicitation of judgments is made and an effective trace of the elicitation process as possible as one can. While the resultant expert judgments can remain to a large extent substantiated with formal elicitation methods, their applicability however is often limited due to restriction of available resources (e.g., time, budget, and number of qualified experts, etc) as well as a scope of the analysis. For this reason, many engineering and decision-making problems have not always performed with a formal/structured pattern, but rather relied on a pertinent transition of the formal process to the simplified approach. The purpose of this paper is (a) to address some insights into the balanced use of formally structured and simplified approaches for the explicit use of expert judgments under resource constraints and (b) to discuss related decision-theoretic issues.