• 한국응용곤충학회:학술대회논문집
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• 한국응용곤충학회 2005년도 춘계 학술발표회
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• pp.107-107
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• 2005

• 한국정보과학회논문지:시스템및이론
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• 제33권1_2호
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• pp.92-104
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• 2006

본 논문에서 제안하는 기법은 기존의 첨단 배치기인 Kraftwerk (& KraftwerkNC)와 Mongrel을 개선 확장한 것으로써, 광역배치에서 셀 중첩을 효과적으로 해결하는 Mongrel의 ripple move 기법과 force directed 광역배치기인 KraftwerkNC의 강력한 성능을 결합한 것이다. 제안한 기법에서는 Mongrel의 ripple move를 최적화하기 위해 Kraftwerk에서 사용한 힘 분산(force spreading)기법을 이용한다. 셀 밀집을 개선시키고, 배선길이를 최적화하는 과정에서 타이밍을 위해 넷 제약조건들이 고려된다. 제안된 기법을 통해 얻은 실험 결과는 배선길이 뿐만 아니라 타이밍에서 향상된 결과를 보여준다.

• Journal of Periodontal and Implant Science
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• 제23권1호
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• pp.97-108
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• 1993

치주조직의 초기치유과정에서 가장 중요한 역할을 하는 치주인대세포의 부착과 전개에 대한 형태학적 관찰을 위하여 교정치료 목적으로 발거된 치아로부터 치주인대조직을 채취하여 초기배양하고 동일한 양($5{\times}10^3ml$)의 치주인대 세포를, 2장의 유리가 포함된 35mm 배양접시에 접종한 후, $CO_2$ 배양기에서 배양하여 세포배양개시후 10분, 30분, 90분, 6시간, 12시간, 24시간의 시간간격에 따라서 광학위상차현미경과 주사전자현미경을 이용하여 세포부착과 전개양상을 관찰한 결과 다음과 같은 결과률 얻었다. 10분간 배양한 세포는 구형을 나타내었으며, 기질측의 세포질이 박판엽상으로 확장되어 기질에 부착개시한 양상이 보였다. 배양 30분 후 판모양의 세포돌기인 박판상돌기에서 세사상돌기롤 내어 부착하는 양상이 관찰되었고, 세포표면은 소기포와 미세융모로 덮여 있었다. 90분간 배양한 세포에서 핵은 세포의 중심부에 위치하였고 세포질이 방사선상으로 확장되어 부착된 양상을 보였으며, 미전개된 세포중심부에는 미세융모와 소기포로 덮여져 있었다. 배양 6시간 후 세포는 신장된 양상을 보였고 타원형의 핵이 관찰되었다. 세포의 양극에서 박판상돌기가 관찰되었고 다시 세사상돌기가 분지되는 양상을 보였는데 이 돌기의 말단부는 팽대되어 기질에 부착하였다. 12시간 배양한 후의 치주인대 세포는 뚜렷한극성화를 보이면서 길게 신장된 양상을 나타내었다. 배양 24시간 경과후 신장된 양상의 핵이 세포의 한쪽극에 치우쳐 있었으며, 세포외형은 길게 신장된 방추상의 형태가 관찰되었다.

• 한국수의병리학회:학술대회논문집
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• 한국수의병리학회 2001년도 추계학술대회 및 정기총회
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• pp.29-29
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• 2001

Well bordered solid enlarged 16.7x9.7x8 cm in the size neoplasma was found in a 7-year-old lioness without any clinical signs of diseases in Chonju city zoo and surgically removed. Simple lobes were separated by pale gray yellowish fibrous tissue. The tumor parenchyma was yellowish with numerous cysts, necrotic foci and hemorrhages. Histologically neoplasma was composed of cell nests different in the size and shape with high mitotic activity. Slow invasive spreading on the border was observed. Formation of the narrow ductular lumina bordered the flattened cells leading to keratinization was seen in some places. It was noted by supplemental clinical investigations, that the tumor did not metastasized to other organs. This tumor is considered to be a sample of a malignant tumor without metastatic spreading and was note described in literature yet.

• Macromolecular Research
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• 제11권1호
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• pp.42-46
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• 2003

Cell attachment and proliferation on the polymer films of triblock copolymer(ester-ether)s comprising po1y (L-1actide) (PLLA) and poly (oxyethylene-co-oxypropylene)(PN) were investigated using 3T3 fibroblasts. It was found that on the tissue culture polystyrene(TCPS) and the PLLA control film the cells could spread well while on the copolymer films the cells showed a rounded morphology without spreading and proliferated weakly. Especially, little cells proliferated on the films of copolymer having a LN composition of 20 wt%. While the water absorption of the copolymer films increased with increasing PN content, the contact angle against water of copolymer films immersed in aqueous medium was almost identical, being slightly lower than that of the PLLA film. These properties were compatible with the results of cell attachment. The in vitro hydrolysis of the films of triblock and multiblock type copolymers was faster with increasing PN content. The increased hydrolyzability, the flexibility and the decreased cell attachment suggested that these copolymers may have high potential as biodegradable materials for medical use.

• Molecules and Cells
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• 제41권2호
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• pp.103-109
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• 2018

Calcium ions are involved in the regulation of diverse cellular processes. Fourteen genes encoding calcium binding proteins have been identified in Dictyostelium. CBP7, one of the 14 CBPs, is composed of 169 amino acids and contains four EF-hand motifs. Here, we investigated the roles of CBP7 in the development and cell migration of Dictyostelium cells and found that high levels of CBP7 exerted a negative effect on cells aggregation during development, possibly by inhibiting chemoattractant-directed cell migration. While cells lacking CBP7 exhibited normal development and chemotaxis similar that of wild-type cells, CBP7 overexpressing cells completely lost their chemotactic abilities to move toward increasing cAMP concentrations. This resulted in inhibition of cellular aggregation, a process required for forming multicellular organisms during development. Low levels of cytosolic free calcium were observed in CBP7 overexpressing cells, which was likely the underlying cause of their lack of chemotaxis. Our results demonstrate that CBP7 plays an important role in cell spreading and cell-substrate adhesion. cbp7 null cells showed decreased cell size and cell-substrate adhesion. The present study contributes to further understanding the role of calcium signaling in regulation of cell migration and development.

• 한국재료학회지
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• 제20권7호
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• pp.392-400
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• 2010

The electrospinning process was established as a promising method to fabricate nano and micro-textured scaffolds for tissue engineering applications. A BCP-loaded PCL micro-textured scaffold thus can be a viable option. The biocompatibility as well as the mechanical properties of such scaffold materials should be optimized for this purpose. In this study, a composite scaffold of poly ($\varepsilon$-caprolactone) (PCL)-biphase calcium phosphate (BCP) was successfully fabricated by electrospinning. EDS and XRD data show successful loading of BCP nano particles in the PCL fibers. Morphological characterization of fibers shows that with a higher loaded BCP content the fiber surface was rougher and the diameter was approximately 1 to 7 ${\mu}m$. Tensile modulus and ultimate tensile stress reached their highest values in the PCL- 10 wt% BCP composite. When content of nano ceramic particles was low, they were dispersed in the fibers as reinforcements for the polymer matrix. However, at a high content of ceramic particles, the particles tend to agglomerate and lead to decreasing tensile modulus and ultimate stress of the PCL-BCP composite mats. Therefore, the use of nano BCP content for distribution in fiber polymer using BCP for reinforcement is limited. Tensile strain decreased with increasing content of BCP loading. From in vitro study using MG-63 osteoblast cells and L-929 fibroblast like cells, it was confirmed that electrospun PCL-BCP composite mats were biocompatible and that spreading behavior was good. As BCP content increased, the area of cell spreading on the surface of the mats also increased. Cells showed the best adherence on the surface of composite mats at 50 wt% BCP for both L-929 fibroblast-like cells and MG-63 osteoblast cell. PCL- BCP composites are a promising material for application in bone scaffolds.

• Journal of Microbiology and Biotechnology
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• 제25권11호
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• pp.1849-1855
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• 2015

Staphylococcus aureus plays an important role in sepsis, septic shock, pneumonia, and wound infections. Here, we demonstrate that Lactobacillus plantarum extracts inhibited S. aureus-induced cell death of a human epithelial cell line, HT-29. In particular, we have shown that S. aureus-induced cell death was abolished by neutralization of α-toxin, indicating that α-toxin is the major mediator of S. aureus-induced cell death. DNA fragmentation experiment and caspase assay revealed that the S. aureus-induced cell death was apoptosis. L. plantarum extracts inhibited the generation of effector caspase-3 and the initiator caspase-9 in S. aureus- or α-toxin-induced cell death. Moreover, expression of Bcl-2, an anti-apoptotic protein, was activated in L. plantarum extract-treated cells as compared with the S. aureus- or α-toxin-treated only cells. Furthermore, S. aureus-induced apoptosis was efficiently inhibited by lipoteichoic acid and peptidoglycan of L. plantarum. Together, our results suggest that L. plantarum extracts can inhibit the S. aureus-mediated apoptosis, which is associated with S. aureus spreading, in intestinal epithelial cells, and may provide a new therapeutic reagent to treat bacterial infections.

• 통합자연과학논문집
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• 제16권2호
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• pp.47-51
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• 2023

Ras small GTPases are involved in regulating various cellular signaling pathways including cell migration, proliferation, and differentiation. Ras GTPase subfamily is comprised of 15 proteins; 11 Ras, 3 Rap, and one Rheb related protein. Some Ras proteins, such as RasC and RasG, have been identified for their major functions, but there are proteins whose functions have not been studied yet, such as RasU and RasX. Here, we investigated the roles of RasU in cell motility and development. RasU shows the highest homology with RasX. To investigate the functions of RasU, rasU null cells were used to observe the phenotype. Cells lacking RasU were larger and more spread than wild-type cells. These results indicate that RasU plays a negative role in cell spreading. In addition, we investigated the roles of RasU in cell motility and development of Dictyostelium cells and found that rasU null cells exhibited decreased random migration speed and delayed developmental process. These results suggest that RasU plays an important role in cell motility and development.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.587-602
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• 1995

치근면처리후 신부착에 관여하는 치주인대 세포의 부착을 비교하기위해 치근활택술만 시행한 군, 치근활택술후 구연산처리한 군, 치근활택술후 테트라사이클린처리한 군으로 분류하여 치주인대세포에 대한 부착양상을 관찰하였다. 세포증식실험에서는 각군의 시편을 조직배양지에 넣고 $1{\times}10^5$ cells/ml 농도의 치주인대세포를 1 ml씩 넣어 6시간 배양후 새 배양기에 옮겨 24시간, 28시간 및 72시간동안 배양하여 세포수를 측정하였고 세포부착후 주사전자현미경 관찰에서는 각각의 조직배양기에 1${\times}$104 cells/ml의 치주인대세포를 가진 배양액 1 ml씩을 넣어 배양하여 세포배양개시 푸 30분, 6시간, 24시간에 고정한후 탈수하고 임계점으로 건조시켜 주사전자현미경을 사용하여 세포부착양상을 관찰하였다. 세포증식실험에서 부착된 세포수가 24, 48, 72시간 모두에서 치근활택군, 구연산처리군, 테트라사이클린처리군순으로 높았고 치근활택군과 테트라사이클린처리군사이에 통계학적 유의성이 있었으며 24, 48시간에서는 구연산처리군과 테트라사이클린처리군사이에 통계학적 유의성이 있어 탈회군이 비탈회군보다 증가된 세포증식을 보였고 테트라사이클린처리군이 구연산처리군보다 증식된 세포수가 많았다. 주사전자현미경관찰에서 모든 군이 24시간 경과 후 전개가 거의 완성되는 양상을 보였고 테트라사이클린처리군의 초기전개가 다소 빠르게 진행됨이 관찰되었으며 테트라사이클린처리군과 구연산처리군이 세포가 부착되는 양상에서 치근활택군보다는 전개가 다소 진전된 양상을 나타내었으나 두 군간에는 유사한 전개가 진행되어 탈회면과 비탈회면의 차이는 나타나나 두 군간의 뚜렷한 차이는 보이지 않았다. 이상의 연구결과 테트라사이클린과 구연산처리가 치근활택술만 시행한 경우보다 치주인대세포의 증식 및 전개에 더 유리하며, 테트라사이클린과 구연산은 치주인대세포의 전개양상은 유사하나 치주인대세포증식에 있어서는 테트라사이클린에서 더 나은 효과가 있었다.