• 천문학논총
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• 제30권2호
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• pp.507-509
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• 2015

This work aims to study the evolution of galaxies, located in the dense environment of the NGC 4095 compact group, which have recession velocities 6,000 < v ($km\;s^{-1}$) < 8,000. Imaging observations for BV $R_c$ broad-band, and [$S\small{II}$] and red-continuum narrow-band were carried out with the 2.4 m Thai National Telescope (TNT) at Doi Inthanon, Chiang Mai, Thailand. The sample contains 13 galaxies, consisting of 8 spirals, 4 ellipticals and 1 irregular morphological type. Late type galaxies tend to be bluer than early type galaxies. The results show that most of the late type galaxies have ongoing star formation activity, which could be triggered by galaxy-galaxy or tidal interactions, and that young massive stars in these galaxies cause their colors to be bluer than the early type galaxies.

• 천문학논총
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• 제30권2호
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• pp.465-467
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• 2015

We presents a study of interactions between galaxies in the low-redshift group known as the NGC 4065 group. Imaging data were taken using the 2.4 meter telescope at the Thai National Observatory (TNO) for B, V and $R_c$ broadband filters and [$S\small{II}$] and Red-continuum narrowband filters. There are 21 galaxies in our sample. The results show that most early type galaxies (ETGs) with equivalent width EW($H{\alpha}$) < $10{\AA}$ are gas-deficient galaxies, while late type galaxies (LTGs) show more EW($H{\alpha}$) and are bluer than the ETGs. This means that star formation activity in the LTGs could be triggered by tidal interactions between galaxy members due to dense environmental effects in the compact group.

• 한국수정란이식학회지
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• 제27권3호
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• pp.171-174
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• 2012

Various small molecules can be used to control major signaling pathways to enhance stemness and inhibit differentiation in murine embryonic stem cell (mESC) culture. Small molecules inhibiting the fibroblast growth factor (FGF)/ERK pathway can preserve pluripotent cells from stimulation of differentiation. In this study, we aimed to evaluate the effect of pluripotin (SC-1), an inhibitor of the FGF/ERK pathway, on the colony formation of outgrowing presumptive mESCs. After plating the zona pellucida-free blastocyst on the feeder layer, attached cell clumps was cultured with SC-1 until the endpoint of the experiment at passage 10. In this experiment, when the number of colonies was counted at passage 3, SC-1-treated group showed 3.4 fold more mESC colonies when compared with control group. However, after passage 4, there was no stimulating effect of SC-1 on the colony formation. In conclusion, SC-1 treatment can be used to promote mESC generation by increasing the number of early mESC colonies.

• 한국과학교육학회지
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• 제37권2호
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• pp.301-311
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• 2017

본 연구에서 연구자는 학생들이 마찰력을 주제로 소집단 토론을 진행할 때 어떤 특성을 보이는지 살펴보았고, 공통맥락이라는 키워드가 연구에서 나타난 현상을 잘 설명한다고 생각하여 이 용어를 재정의하고 공통맥락 형성의 관점에서 학생들의 토론 양상을 살펴보았다. 특히 학생들이 논의하는 과정에서 공통맥락의 형성 과정이 구성원들의 논의를 거쳐 명시적으로 나타나는지, 공통맥락이 이미 형성되어 있다고 암묵적으로 가정하거나 간단한 확인만 거치는지에 대해 살펴보았다. 연구 결과 공통맥락의 형성 과정이 명시적으로 드러난 사례로는 문제 상황의 확인(특히 2번 문제에서 A의 운동), 마찰력의 본성 및 특성, 여러 가지 힘들의 성질, 관성계 및 비관성계와 관련한 논의 등이 있었다. 한편, 구성원들이 공통맥락이 이미 암묵적으로 형성 되어 있다고 가정하고 논의를 이어 나간 것 중 본 연구에서 특징적인 것으로는 마찰력 규칙에 대한 지식이 있었고, 마찰력 규칙을 오용하는 사례도 찾아볼 수 있었다. 한편, 연구자는 질문자, 수용자, 다른 의견을 가진 학생의 존재가 긍정적인 조별 토론에 중요하다는 사실을 발견했고, 특히 질문자는 본 연구 사례에서 매우 중요한 역할을 하였음을 확인할 수 있었다. 본 연구의 결과는 담화의 형태를 중심으로 분석하는 선행연구들과는 달리 구체적인 수업의 주제가 소집단 조별 토론에 어떤 영향을 주는지 분석했다는 점에서 그 의의를 가진다고 본다.

• Journal of Periodontal and Implant Science
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• 제27권4호
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• pp.845-866
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• 1997

Several experimental studies showed that the application of small amounts of electric current to bone stimulated osteogenesis at the site of the cathode and suggests that the application of electrical currents to periodontal defects could promote bone and cementum formation. The purpose of this study was to determine the effect of direct microcurrent to the periodontal regeneration of class III furcation defects in dogs. Class III furcation defects were surgically created on the third and the fourth premolars bilaterally in the mandibles of nine mongrel dogs. Experimental periodontitis were induced by placing small cotton pellets into the created defects for 3 weeks. The experimental sites were divided into three groups according to the treatment modalities: Group I-surgical debridement only; Group II-allogenic demineralized freeze dried bone grafting; Group III-allogenic demineralized freeze dried bone grafting and electrical stimulation. For fluorescence microscopic evaluation, calcein, oxytetracycline HCI and alizarin red were injected 2, 4 and 8 weeksfS days prior to sacrifice) after surgery. The animals were sacrificed in the 1st, 2nd, 4th and 8th week after periodontal surgery and the decalcified and undecalcified specimens were prepared for histological and histometrical examination. After the first and the second weeks, gingival recession was more severe in group I than groups II and III. After the fourth and the eighth weeks, there was no difference in the width of junctional epithelium and connective tissue attachment among the three groups, but the width of connective tissue attachment increased in group II at the eighth week, compared to the fourth week. The amount of bone repair in new attachment was significantly greater in group III, compared to groups I and II. New attachment formation was significantly greater in group III, compared to groups I and group II. These results suggest that electrical stimulation using microcurrent generator could be a useful tool for periodontal regenerative therapy in class III furcation defect.

• KIEAE Journal
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• 제12권6호
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• pp.3-10
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• 2012

Small park in the community is a public asset that is commonly used by the residents daily and performs an important role to activate the community. The purpose of this study is to draw a small park plan through community participation. In concrete, this study tries to find out the demand of the residents about their small park plan, observe the changes in their demand in the process of debate and analyze the effect of the residents' participation. Small group workshop method was adopted in the study and three groups were set up and surveys were made in two stages. Two dimensional pictogram cards and three dimensional digital park formation tools were used. The results of workshop study indicated as follows: Firstly, residents wanted to have community farming garden, green house and flower garden to grow plants, natural walls and safe resting facilities. Secondly, individual and diverse opinions presented at first could be converted to common opinions through mutual exchanges of opinions in the process of debates. Thirdly, digital park formation program functioned well as an effective visual tool to draw the attention and quick responses of the residents and to reach an agreement. It is expected that the results of this study show the effectiveness of residents' participation tools in the process of drawing agreements in the community society that requires the residents' demands and agreement and this study will be usefully utilized in planning community spaces with residents' participation hereafter.

• 천문학회보
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• 제39권2호
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• pp.60.2-60.2
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• 2014

Hierarchical structure of star-forming regions is widespread and may be characteristic of all star formation. We studied the hierarchical structure of star-forming regions in the Local Group galaxies (M31, M33, Phoenix, Pegasus, Sextans A, Sextans B, WLM). The star-forming regions were selected from Galaxy Evolution Explorer (GALEX) far-UV imaging in various detection thresholds for investigating hierarchical structure. We examined the spatial distribution of the hot massive stars within star-forming regions from Hubble Space Telescope (HST) multi-band photometry. Small compact groups arranged within large complexes. The cumulative mass distribution follows a power law. The results allow us to understand the hierarchical structure of star formation and recent evolution of the Local Group galaxies.

• Journal of Periodontal and Implant Science
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• 제31권2호
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• pp.421-436
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• 2001

Transforming growth $factor-{\beta}(TGF-{\beta})$is a polypeptide biologic mediator considered to play a role in promoting bone formation in bony defect area. The purpose of this study was to examine the effect of $TGF-{\beta}$ to the periodontal regeneration of class III furcation defect in dogs. Classs III furcation defects were surgically created on the third and the fourth premolars bilaterally in the mandibles of eight mongrel dogs. Experimental periodontitis were induced by placing small cotton pellets into the created defects for 3 weeks. Experimental sites were divided into 4 groups according to the treatment modalities: Group I-Surgical debridement only; Group II-allogenic demineralized freeze dried bone grafting; Group III-allogenic demineralized freeze dried bone soaked in $TGF-{\beta}(4ng/10{\mu}l)$grafting; Group IV-allogenic demineralized freeze dried bone soaked in $TGF-{\beta}(20ng/10{\mu}l)$ grafting. The animals were sacrificed in the 8th week after periodontal surgery and the decalcified and undecalcified specimens were for histological and histometric examination. Although no significant differences was seen in the length of epitheial growth and connective attachment, group III showed the least apical migration among treatment groups. The amount of bone repair was significantly greater in group III, IV compared to group I and group II. New attachment formation was significantly greater in group III and group IV compared to group I and group II. These results suggest the allogenic demineralized freeze dried bone with $TGF-{\beta}$ in class III furcation defect has the potentiality of promoting alveolar bone formation and periodontal regeneration.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.27.1-27.9
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• 2016

Background: The objective of this study was to place bone graft materials in cranial defects in a rabbit model and compare their bone regenerating ability according to the size and density of demineralized dentin matrix (DDM). Methods: We selected nine healthy male rabbits that were raised under the same conditions and that weighed about 3 kg. Two circular defects 8 mm in diameter were created in each side of the cranium. The defects were grafted with DDM using four different particle sizes and densities: 0.1 mL of 0.25- to 1.0-mm particles (group 1); 0. 2 mL of 0.25- to 1.0-mm particles (group 2); 0.1 mL of 1.0- to 2.0-mm particles (group 3); and 0.2 mL of 1.0- to 2. 0-mm particles (group 4). After 2, 4, and 8 weeks, the rabbits were sacrificed, and bone samples were evaluated by means of histologic, histomorphometric, and quantitative RT-PCR analysis. Results: In group 1, osteoblast activity and bone formation were greater than in the other three groups on histological examination. In groups 2, 3, and 4, dense connective tissue was seen around original bone even after 8 weeks. Histomorphometric analysis of representative sections in group 1 showed a higher rate of new bone formation, but the difference from the other groups was not statistically significant. RT-PCR analysis indicated a correlation between bone formation and protein (osteonectin and osteopontin) expression. Conclusions: DDM with a space between particles of $200{\mu}m$ was effective in bone formation, suggesting that materials with a small particle size could reasonably be used for bone grafting.

• Transactions on Electrical and Electronic Materials
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• 제12권5호
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• pp.218-221
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• 2011

We modified the optical properties of the $CuInS_2$ nanocrystal (NC) by alloying. Nanocrystals (NCs) with alloyed cores were synthesized by refluxing the as-synthesized $CuInS_2$ NCs with a mixture of cadmium acetate, zinc acetate and palmitic acid. The shift in emission wavelength of the NCs after shell layer formation was minimized by alloying. The photoluminescence (PL) spectra showed significant reduction of emission intensity. A detailed study on the emission process of NCs implies that the formation of shell layers with small lattice mismatch minimized the mismatch strain generated from the shell layers in contrast to core alloyed NCs. In particular, time-resolved PL spectra of the NCs showed a significant increase in the lifetime of excited carriers by modifying the band alignment of the NCs by modifying the shell composition.