• 한국융합학회논문지
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• 제8권9호
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• pp.199-209
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• 2017

본 연구는 줄기세포분야의 융합연구 형태와 각 영역별 연구자의 역할을 확인하기 위해 사회네트워크분석을 수행하였다. 자료는 PubMed 데이터베이스에서 1996년부터 2012년까지 만능유도줄기세포와 배아줄기세포를 주제로 발표된 270편의 논문과 성체줄기세포와 중간엽줄기세포 영역의 580편 논문을 추출하였다. 각 영역의 논문에서 공저자 515명과 1,515명을 추출하여 분석하였다. 분석 방법은 사회네트워크분석으로 연결정도중심성, 매개중심성을 확인하고 공저자 네트워크를 구현한 후 연구자의 역할을 확인하였다. 분석결과 공저자 네트워크 상 성과가 높은 핵심 연구자와 중개 연구자를 확인할 수 있었다. 핵심 연구자는 연결정도중심성은 높지만 매개중심성이 높지 않을 수 있으며, 연결정도중심성은 낮으나 매개중심성이 높아 연구자를 연결시키는 중개 연구자를 확인하였다. 공저자 네트워크분석은 분야별 핵심 연구자를 찾아 공동연구를 수행하여 성과를 향상시키고, 연구개발과제 심사를 위한 분야별 전문가 추천을 위한 객관적 자료로 활용이 가능할 것이다.

• 대한의용생체공학회:의공학회지
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• 제29권3호
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• pp.212-221
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• 2008

The total hip replacement (THR) has been used as the most effective way to restore the function of damaged hip joint. However, various factors have caused some side effects after the THR. Unfortunately, the success of the THR have been decided only by the proficiency of surgeons so far. Hence, It is necessary to find the way to minimize the side effect caused by those factors. The purpose of this study was to suggest the definite data, which can be used to design and choose the optimal hip implant. Using finite element analysis (FEA), the biomechanical condition of bone cement was evaluated. Stress patterns were analyzed in three conditions: cement mantle, procimal femur and stem-cement contact surface. Additionally, micro-motion was analyzed in the stem-cement contact surface. The 3-D femur model was reconstructed from 2-D computerized tomography (CT) images. Raw CT images were preprocessed by image processing technique (i.e. edge detection). In this study, automated edge detection system was created by MATLAB coding for effective and rapid image processing. The 3-D femur model was reconstructed based on anatomical parameters. The stem shape was designed using that parameters. The analysis of the finite element models was performed with the variation of parameters. The biomechanical influence of each parameter was analyzed and derived optimal parameters. Moreover, the results of FE A using commercial stem model (Zimmer's V erSys) were similar to the results of stem model that was used in this study. Through the study, the improved designs and optimal factors for clinical application were suggested. We expect that the results can suggest solutions to minimize various side effects.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.245-248
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• 1997

Excessive stress on the bone-stem interface may cause local micromotion that could produce midthigh pain, interface bone resorption and prevent bony ingrowth. It is important for clinician and prosthetic designer to develop an understanding of the load transfer mechanism, its associated stress pattern and its relationships with the particular mechanical characteristics of the femoral stem designs. Finite element method (FEM) is preeminently suited to provide information in this respect. The authors developed 3-dimensional numerical finite element models implanted with the straight stem which is composed of total 1170 elements of 8 nodes and with the curved stem which is composed of total 885 elements of 8 node, and analysed the relative micromotions between the straight stem and the curved stem in immediate postoperative stage of an uncemented total hip replacement in load simulating the single leg stance. The results showed that the rotational displacement was occupied over 90% of total micromotion in both types of stem and was peak at the proximal medial portion of the stem, but markedly less distally. The curved stem was more stable especially in terms of rotational stability. It is recommended that surgeons do not allow the patient weight bearing until bony ingrowth was achieved. In the future more attention should be drawn to increase initial rotational stability of the two types of femoral stem to prevent loosening from excessive micromotion.

• Asian Pacific Journal of Cancer Prevention
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• 제13권6호
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• pp.2935-2941
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• 2012

Biological response modifiers (BRMs) can alter interactions between the immune system and cancer cells to boost, direct, or restore the body's ability to fight disease. Mice with ethylnitrosourea- (ENU) induced leukemia were here used to monitor the therapeutic efficacy of lipopolysaccaride (LPS), Bacillus Calmette Guerin (BCG) and sheep erythrocytes (SRBC). Flow cytometry based CD34+ positivity analysis, clonogenicity, proliferation and ultrastructure studies using scanning electron microscopy (SEM) of stem cells in ENU induced animals with and without BRMs treatment were performed. BRMs improved the stem-stromal relationship structurally and functionally and might have potential for use as an adjunct in human stem cell therapy.

• East Asian mathematical journal
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• 제39권4호
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• pp.377-392
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• 2023

The purpose of this research was to investigate mathematics teachers' beliefs regarding the implementation of STEM approaches in secondary school mathematics classes and to identify the factors influencing their beliefs. A survey on teachers' beliefs about applying STEM in mathematics classes was developed and distributed online to mathematics teachers from middle and high schools in two metropolitan areas. Eighty-two surveys were returned from the teachers. Factor analysis revealed that the items were distributed among five main aspects. The findings indicated that most teachers believed in the necessity of implementing STEM education. However, some teachers expressed concerns about the effectiveness of implementation due to the lack of materials, resources, and equipment needed for STEM implementation.

• 농업과학연구
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• 제24권1호
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• pp.6-10
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• 1997

초장, 엽수, 경수, 경직경, 엽장, 엽폭, 근경생산량을 평가하기위하여 수집 한 94 clone은 경수와 근경생산량에서 유용한 변이를 보여주었다. 초장, 엽수, 엽장, 엽폭, 경직경은 약간의 변이가 관찰되었다. 작물학적 특성간의 단순상관은 근경생산량과 정의 상관을 보여주었고 엽수, 초장, 경직경은 근경생산량과 고도의 정의 상관을 보여주었다. 경로계수분석을 통하여 경수, 엽수, 경직경순으로 근경생산에 직접효과를 준다는 결과를 얻을 수 있었다. 엽수를 통한 초장의 간접효과가 가장 크게 나타났고, 엽수를 통한 엽장, 엽폭과 경직경을 통한 초장, 엽장, 엽폭에서도 간접효과가 관찰되었다. 선발의 관점에서 볼 때, 초장, 엽수, 경수와 같은 특성들은 좋은 유전형을 선발하기에 적합하다고 여겨진다.

• 한국동물학회지
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• 제33권4호
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• pp.446-453
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• 1990

본 실험은 레티노익산에 의해 F9 Teratocarcinoma Stem Cell의 분화를 유도하고 이분화과정에서 세포형태의 변화와 라미닌유전자의 발현을 조사 하였다. 분화되지 않은 F9 Stem Cell은 지속적으로 증식을 하며 세포간의 간격을 구분하기 어령루 뿐만 아니라 불규칙적인 모양을 하고 있으나,레티노익산과 dibutyryl cyclic AMP처리후의 분화된 F9세포는 둥글고 평평한 모양을 나타내며 세포성장은 중지되었다. Northern blot분석에 의하여 레티노익산과 cyclic AMP처리 후의 F9세포내에서 라미닌 유전자의 발현은 현저하게 증가하였다. 즉, 라미닌 B1유전자 발현은 분화과정 동안 최소한 30배, 라미닌 B2 유전자의 발현은 약 20배 증가하였다. 또한 라미닌 항체를 이용한 면역형광 분석결과는 Northern 분석결과와 일치하게 분화 후에 라미닌 단백질 합성이 크게 증가되었으며, 생성된 라미닌 단백질은 거의 세포표면에 분포된 것으로 나타났다. 이러한 결과로부터, 레티노익산에 의해 F9 Stem Cell의 분화가 유도되며 이 분화과정에서의 형태적인 변화와 진행은 라미닌의 생성과 밀접한 관련이 있다고 추측된다.

• 보건행정학회지
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• 제23권4호
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• pp.314-325
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• 2013

Background: Stem cell research competition is accelerating globally since President Obama signed an executive order, repealing Bush-era policy that limited use of federal tax dollars for embryonic stem cell research. Methods: In this paper, we conducted a comparative analysis of stem cell research policy changes in three countries, including the Human Fertilisation Embryology Act (HFEA) of UK, executive order 13,505 (removing barriers to responsible scientific research involving human stem cells) of USA, and Bioethics and Safety Act of South Korea. Debates on stem cell research are based on conflicts of fundamental beliefs that exist in the supporting and opposing coalitions. We compared regional characteristics of the advocacy coalitions in three countries and presented various factors that might be related to the policy changes. Results: The UK government, parliament, and the HFEA have sought expert consultations and public opinions to establish guidelines. UK has made social consensus through continued discussion for a long time. US President's veto power was one strongest factors influencing policy. South Korean policy was influenced by public opinion and policy brokers. Also, South Korea has not made social consensus. UK had a strong leadership and strong adjustment of coalitions but US and South Korea had not. Dr. Hwang's scandal has had one of the greatest impacts on policy decision in South Korea. Conclusion: The power of public opinion was critical in all three countries. In particular, the influence of public opinion was noticeable in South Korea. Also it turned out that in US and South Korea, the presence of a policy broker who could pursue his or her goals was the most powerful factor among the advocacy coalition factors.

• Journal of Korean Dental Science
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• 제11권2호
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• pp.62-70
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• 2018

Purpose: Bone marrow has long been a source of primary cells. This study was performed to evaluate the effects of age and sex on the cellular viability and expression of stem cell markers of mRNA and on the protein expression of bone marrow stem cells (BMSCs) derived from healthy donors. Materials and Methods: Stem cells were isolated from human bone marrow and plated in culture plates. The shape of the BMSCs was observed under inverted microscope. Quantitative cellular viability was evaluated using a Cell-Counting Kit-8 assay. The expression of stem cell surface markers was tested and a series of quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot was performed to evaluate the expression in each group. Result: The shapes of the cells at 20s, 30s, and 50s were similar to each other. No significant changes in cellular viability were noted among different age groups or sex groups. The BMSCs expressed CD44, CD73, and CD90 surface markers but did not express CD14 and CD34. There were no noticeable differences in CD surface markers among the different age groups. The expressions of CD surface markers were similar between men and women. No significant differences in the secretion of vascular endothelial growth factors (VEGFs) were noted at Day 3 between different age groups. qRT-PCR regarding the expression showed differences between the age groups. However, Western blot analysis showed a decrease in expression but did not reach statistical significance (P>0.05). Conclusion: This study clearly showed no significant differences in shape, cell viability, expression of stem cell surface markers, or secretion of human VEGF among different age groups. However, western blot analysis showed a tendency of age-related decrease which did not reach statistical significance. Collectively, autologous or allogeneic BMSCs should be meticulously applied to obtain optimal results regarding age and sex.

• 문화기술의 융합
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• 제8권5호
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• pp.431-435
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• 2022

과학기술 분야(STEM, Science, Technology, Engineering and Medicine)는 빠르게 변화하고 있다. 최근에는, 인터넷 및 웹 기술의 눈부신 발전과 함께, 전 세계적으로 접근할 수 있는 환경이 조성되어 STEM 지식 공유의 장벽이 낮아지고 있다. 이러한 정보 기술의 발전은 결과적으로 학술지의 출판(보급) 모델을 변화시켰다. 본 연구의 목적은STEM 분야에서 오픈 액세스 모델을 적용시켜 개발한 정보시스템에 대한 이용자들의 만족도를 평가하여 개선사항을 도출하는 데에 있다. 구조화된 설문지를 활용한 온라인 조사를 통하여, 지난 1월부터 2월까지, 총 204명의 이용자가 참여하였다. 수집한 데이터는 정량적 통계기법을 이용하여 분석하였다. 웹사이트 속성 별 특성을 분석하기 위하여 IPA (Importance Performance Analysis)기법을 활용하였다. 변수들 간 중요도와 만족도(실행도)를 파악하여 중요도 대비 만족도가 상대적으로 낮은 영역들을 도출하였다. 오픈액세스 정보시스템에 대한 이용자들의 전반적인 만족도는 81.2점, 사회적 신뢰도는 85.9점으로 각각 비교적 높게 나왔다. 본 연구에서 주목해야 하는 사항은 가장 취약한 영역으로 드러난 시스템 이용 환경에 대한 만족도 부분이다. 최적화된 상업적 검색도구들에 노출되어 있는 이용자들에게 검색하는 과정에서 속도는 매우 중요한 검색시스템 평가 요인 가운데 하나이다. 이용자들의 니즈를 반영하여 신속하게 검색결과로 제공할 수 있도록 지속적인 평가를 통한 개선 작업이 필요하다.