• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.74-75
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• 2011

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2004.07a
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• pp.31-31
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• 2004

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.44.2-44.2
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• 2010

최근 골손상이 있을 경우 골 형성을 유도하고 기능을 부여하여 단순한 골조직의 대체를 위한 지지체가 아닌 한층 더 나아간 지지체의 연구가 활발히 진행되고 있다. 뼈 형성 억제 인자를 억제하거나 촉진인자를 첨가하여 뼈의 형성이 증가시키고, 뼈 형성과정에 관여하는 신호체계를 유도하는 어떤 물질을 첨가하여 뼈의 형성을 증가시킬 수 있다. 줄기세포는 다양한 세포로 분화할 수 있는 능력이 있는데 그 과정에서 여러 가지 signal이 관여한다. 그 중 wnt signaling은 줄기 세포가 분화하는 과정뿐만 아니라 세포의 사멸, 이동에 있어서도 매우 중요한 역할을 하며, 줄기세포의 운명 결정에 영향을 미친다고 알려져 있다. Silicon은 조골세포의 부착과 증식, 세포의 활성을 증가시키며 뼈의 형성과정과 석회화 과정에서 중요한 역할을 한다. 또한 BMP-2, collagen 등과 같은 유전자의 발현을 증가시킨다. 따라서 본 연구에서는 Silicon이 조골세포로의 분화과정에 관여하는 신호전달 중 wnt 신호에 미치는 영향에 대해 유전자의 발현 양상과 단백질의 발현 양상을 살펴보기 위해 각각 RT-PCR과 western-blotting을 수행하였다.

• Development and Reproduction
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• v.15 no.4
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• pp.273-279
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• 2011

Epigenetic regulation is a phenomenon that changes the gene function without changing the underlying DNA sequences. Epigenetic status of chromosome is regulated by mechanisms such as histone modification, DNA modification, and RNAi silencing. In this review, we focused on histone methylation for epigenetic regulation in ES cells. Two antagonizing multiprotein complexes regulate methylation of histones to guide expression of genes in ES cells. The Polycomb repressive complex 2 (PRC2), including EED, EZH2, and SUZ12 as core factors, contributes to gene repression by increasing trimethylation of H3K27 (H3K27me3). In contrast, the Trithorax group (TrxG) complex including MLL is related to gene activation by making H3K4me3. PRC2 and TrxG accompany a variety of accessory proteins. Most prominent feature of epigenetic regulation in ES cells is a bivalent state in which H3K27me3 and H3K4me3 appear simultaneously. Concerted regulation of PRC2, TrxG complex, and H3K4- or H3K27-specific demethylases activate expression of pluripotency-related genes and suppress development-related genes in ES cells. Modified balance of the regulators also enables ES cells to efficiently differentiate to a variety of cells upon differentiating signals. More detailed insights on the epigenetic regulators and their action will lead us to better understanding and use of ES cells for future application.

• The Journal of the Korean dental association
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• v.48 no.2
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• pp.106-112
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• 2010

Tissue engineering has been enhanced by advance in biomaterial nature, surface structure and design. In this paper, I report specifically vertically aligned titania ($TiO_2$) nanotube surface structuring for optimization of titanium implants utilizing nanotechnology. The formation, mechanism, characteristics of titania nanotubes are explained and emerging critical role in tissue engineering and regenerative medicine is reviewed. The main focus of this paper is on the unique 3 dimensional tubular shaped nanostructure of titania and its effects on creating epochal impacts on cell behavior. Particularly, I discuss how different cells cultured on titania nanotube are adhered, proliferated, differentiated and showed phenotypic functionality compared to those cultured on flat titanium. As a matter of fact, the presence of titania nanotube surface structuring on titanium for dental applications had an important effect improving the proliferation and mineralization of osteoblasts in vitro, and enhancing the bone bonding strength with rabbit tibia over conventional titanium implants in vivo. The nano-features of titania nanotubular structure are expected to be advantageous in regulating many positive cell and tissue responses for various tissue engineering and regenerative medicine applications.

• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.315-322
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• 2000

Effects of the simulated acid rain on the growth response and the structural features were studied with the 3 month old seedlings of G. biloba and P. thunbergii treated with acid rain of pH 5.6, 4.0, 3.2, and 2.4. The diameter and area of tracheid cells in the transectioned stem of G. biloba decreased with acidity of simulated acid rain. The wall thickness of tracheid cells was the thinest at pH 2.4, but there was no different at other levels of pH. Increasing of the acidity, the height of tracheid cells were reduced steadily. The diameter and area of tracheid cells of the transectioned root reduced with decreasing pH of acid rain, but those at pH 3.2 were larger than those at control. The wall thickness and height of tracheid cells of root were gradually decreased with acidity of acid rain. The size variation of the fusiform cambial initials in the stem of G. biloba sections tangentially showed a shortening tendency with treatment of acid rain. The length of ray initials was the shortest at pH 2.4 and reduced with decreasing pH of acid rain. The diameter, area, wall thickness, and height of the tracheid cells in P. thunbergii stem and root decreased with decreasing pH of acid rain. The areas of the pith, cortex, and xylem in P. thunbergii treated with acid rain decreased, but the cortex and pith areas increased significantly after exposure to acid rain of pH 3.2 compared with control.

• Journal of Life Science
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• v.12 no.3
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• pp.294-305
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• 2002

This study was performed to evaluate regenerative effects of intrasplenic stem cell transplantation after partial hepatectomy. To evaluate the regenerative effects, Sprague Dawley rats were used. In vivo the embryonic stem cells of blastocysts were collected from superovulated rats on day 3.5 after the vaginal plug checked. The embryonic stem cells were cocultured with hepatocytes for 8 days, they were transplanted into the spleen. After the intrasplenic transplantation of cultured stem cells, they were initially distributed near the periarterial lymphatic sheath after transplantation in the hematoxylin-eosin staining. Their number were formely increased and their size enlarged at forming small lobules. The embryonic stem cells in the culture proliferated and initially proliferated around the periarterial lymphatic sheath and later they around the trabecula with blood vessels. After the transplantation of stem cells, their cell organelles were well developed rough endoplasmic reticulum at the 20th with prominent epidermal growth factor reaction, developed smooth endoplasmic reticulum at the 30th day, well differentiated bile canaliculi with increased transforming growth factor-$\beta$ and apoptosis reactions.

• Development and Reproduction
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• v.12 no.1
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• pp.67-76
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• 2008

Oxidative damage resulted from reactive oxygen species (ROS) is one of the main causes for the decrease of the viability during in vitro culture and cryopreservation process. This experiment was performed to determine the effects of antioxidants on the human hematopoietic stem cell (HSC) during cryopreservation procedure. HSCs cultured in vitro with or without antioxidants were frozen and then examined for stem cell potential after thawing. The cell viability of thawed HSC was increased in $\alpha$-tocopherol and ascorbic acid treatment group compared to control group ($62.7{\pm}8.0%$) and it was higher in 150 uM $\alpha$-tocopherol treatment group ($70.5{\pm}7.0%$). No significant difference was observed in the membrane integrity in all groups. In auto-differentiation rate, no significant difference was appeared in all groups, but was lower in 150 uM $\alpha$-tocopherol ($7.3{\pm}2.6%$) compared to control group ($10.1{\pm}1.6%$). These results demonstrate that treatment of antioxidants improves the efficiency of cryopreservation for HSC and $\alpha$-tocopherol may be considered effective antioxidant for the protective effect on HSC.

• Journal of Science and Technology Studies
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• v.13 no.2
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• pp.37-70
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• 2013

Christianity has desperately opposed to embryonic stem cell research, regarding it homicide. It made the opinion public many times and has tried to lead Christian to recognize the situation and make an appropriate decision with no actual result. It means that many other factors than religion have an effect on the process of making decision. This article aims to summarize the attitude of Christian believer towards embryonic stem cell research and identify the factors interacting in the developing situation. Also, it try to show how the factors have an influence on the others and Christian believers interpret and accept the information, finally leading to make a conclusion that religious factor have only a narrow influence on the formation and development of the believers' attitude.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2009.02a
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• pp.3-12
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• 2009

특허맵 (Patent Map, 특허동향조사)이란 특정 기술분야에 대한 국내외 특허출원 및 등록현황에 대한 자료를 여러 기준으로 상세하게 분석한 후, 이를 사용목적에 맞게 가공하여 이해하기 쉽게 작성한 자료로 기술의 추이와 특허동향이나 현황을 쉽게 파악할 수 있도록 도표, 기호, 그림 등 다양한 형태로 표현한 것이다. 연구자나 기업들의 R&D와 사업은 연구나 사업의 실패 확률을 줄이기 위해 특허맵, 특허동향조사를 필수적으로 활용한다. 특허동향조사를 활용함으로써 다음의 이점을 제공받을 수 있는데, 즉 연구개발방향의 설정에 활용할 수 있고, 중복연구 및 특허분쟁을 미연에 방지할 수 있다. 또한, 경쟁자의 동향을 용이하게 파악할 수 있으며, 기술개발 추이를 파악하여 미래예측이 가능하다. 이러한 활용을 통해 연구개발 예산을 효율적으로 사용할 수 있게 된다. 또한, 특허맵이나 특허동향조사가 활용되는 시점은 연구기획단계에서부터, 연구개발단계, 비즈니스단계 및 특허소송에 이르기까지 전 과정, 즉 R&D부터 그 활용단계에까지 필수적으로 필요한 도구(tool)라 할 것이다. 본 발표에서는 줄기세포분야에 대한 국내외 특허동향을 조사해 보았다. 국내에서는 2000년 이후부터 관련 기술의 급격한 출원을 보이고 있으며, 서울대, 고려대, 제론, 위스콘신 등 국내외 대학이 주요 출원이었다. 또한, 출원현황을 통한 국내 연구 분야의 활성도는 성체줄기세포가 배아줄기세포에 비하여 월등히 앞서 있음을 파악할 수 있다. 특히, 역분화와 관련된 기술도 국내에 약 10건 정도가 검색되었으며 주로 해외 출원인이 주를 이루고 있다. 해외의 경우, 약 6,800여 건을 검색하였으며 미국에서의 출원이 가장 두드러지고 있다. 특허출원의 추이는 국내와 유사하게 2000년 이후에 급격히 증가되었으며 국내보다 2년 앞선 2004년에 최고의 출원량을 보이고 있다. 주요 출원인으로는 OLYMPUS, GENRO, OSIRIS, JAPAN SCIENCE & TECHNOLOGY, ACT, SYSTEMIX 등의 순서임을 확인할 수 있었다.