• The Korean Journal of Physiology and Pharmacology
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• v.20 no.5
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• pp.459-466
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• 2016

Adipogenic differentiation of mesenchymal stem cells (MSCs) is critical for metabolic homeostasis and nutrient signaling during development. However, limited information is available on the pivotal modulators of adipogenic differentiation of MSCs. Adaptor protein Lnk (Src homology 2B3 [SH2B3]), which belongs to a family of SH2-containing proteins, modulates the bioactivities of different stem cells, including hematopoietic stem cells and endothelial progenitor cells. In this study, we investigated whether an interaction between insulin-like growth factor-1 receptor (IGF-1R) and Lnk regulated IGF-1-induced adipogenic differentiation of MSCs. We found that wild-type MSCs showed greater adipogenic differentiation potential than $Lnk^{-/-}$ MSCs. An ex vivo adipogenic differentiation assay showed that $Lnk^{-/-}$ MSCs had decreased adipogenic differentiation potential compared with wild-type MSCs. Interestingly, we found that Lnk formed a complex with IGF-1R and that IGF-1 induced the dissociation of this complex. In addition, we observed that IGF-1-induced increase in the phosphorylation of Akt and mammalian target of rapamycin was triggered by the dissociation of the IGF-1R-Lnk complex. Expression levels of a pivotal transcription factor peroxisome proliferator-activated receptor gamma ($PPAR-{\gamma}$) and its adipogenic target genes (LPL and FABP4) significantly decreased in $Lnk^{-/-}$ MSCs. These results suggested that Lnk adaptor protein regulated the adipogenesis of MSCs through the $IGF-1/Akt/PPAR-{\gamma}$ pathway.

• Nuclear Engineering and Technology
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• v.35 no.2
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• pp.133-143
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• 2003

Stem-stem nut coefficient of friction(COF) in motor-operated gate/globe valves is one of the important factors which determine the performance of the valve/actuators. The COF is affected greatly by the type and condition of the stem-stem nut lubricants, environmental parameters, surface condition of the stem/stem-nuts, and the number of strokes after the lubrication. In this paper, the measured data of the COFs at stem threads of some safety-related motor-operated gate/globe valves in domestic nuclear power plants are presented. In addition, the performance of the lubricants is evaluated by comparing the COFs among those valves. The results show that the measured COF at torque switch trip are higher than the unwedging COF and conservatively applicable to the unwedging COF. It is also shown that the lubricating performance based on the measured COFs varies with the lubricants.

• Journal of agriculture & life science
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• v.45 no.1
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• pp.15-20
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• 2011

The objective of this study was to develop allometric equations and stem density and biomass expansion factor for Pinus rigida stands in Muju region. The coefficient of determination of the allometric equations in independent variable (dbh) and dependent variable (biomass) was more than 95% with the exception of leaf (78%) and branch(83%). The total biomass was $102Mg\;ha^{-1}$ ($65.9 Mg\;ha^{-1}$ from stem wood, $9.5Mg\;ha^{-1}$ from stem bark, $19.6Mg\;ha^{-1}$ from branch and $7.0Mg\;ha^{-1}$ from leaf). Biomass distribution ratio of Pinus rigida stands showed the highest in stem wood with 64.6%, followed by the branch with 19.2%, stem bark with 9.3% and the leaf with 6.9%. The results indicated that the stem density $(g/cm^{3})$ and the biomass expansion factor were 0.453 and 1.344, respectively.

• Biomedical Science Letters
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• v.22 no.1
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• pp.1-8
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• 2016

Several studies have investigated the various effects of dexamethasone (Dex) on the proliferation and differentiation of mesenchymal stem cells (MSCs). Previously, we reported that co-treatment with L-ascorbic acid 2-phosphate and fibroblast growth factor (FGF)-2 maintained differentiation potential in MSCs through expression of hepatocyte growth factor (HGF). In this study, we investigated the effects of co-treatment with FGF-2 and Dex on the proliferation and differentiation potential of MSCs during a 2-month culture period. Co-treatment with FGF-2 and Dex increased approximately a 4.7-fold higher accumulation rate of MSC numbers than that by FGF-2 single treatment during a 2-month culture period. Interestingly, co-treatment with FGF-2 and Dex increased expression of HGF and maintained adipogenic differentiation potential during this culture period. These results suggest that co-treatment with FGF-2 and Dex preserves the proliferation and differentiation potential during long-term culture.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.415-424
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• 2017

The purpose of this study was to examine the relationship among public's risk characteristics, risk severity, risk perception and risk acceptability of human stem cell technology. The subjects were 300 Koreans selected. The data were analyzed by the exploratory factor analysis, confirmatory factor analysis, correlation analysis and structural equation modeing analysis. The results were as followed. First, public's risk characteristics on human stem cell technology influenced positively on risk severity. Second, public's risk characteristics on human stem cell technology influenced positively on risk perception. Third, public's risk severity on human stem cell technology influenced positively on risk perception. Fourth, public's risk characteristics on human stem cell technology influenced negatively on risk acceptability. Fifth, public's risk severity on human stem cell technology influenced not significantly on risk acceptability. Sixth, public's risk perception on human stem cell technology influenced not significantly on risk acceptability. These results will contribute to develop the risk communication strategy on the acceptability of human stem cell technology.

• BMB Reports
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• v.50 no.2
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• pp.79-84
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• 2017

Emphysema, a pathologic component of the chronic obstructive pulmonary disease, causes irreversible destruction of lung. Many researchers have reported that mesenchymal stem cells can regenerate lung tissue after emphysema. We evaluated if spheroid human adipose-derived mesenchymal stem cells (ASCs) showed greater regenerative effects than dissociated ASCs in mice with elastase-induced emphysema. ASCs were administered via an intrapleural route. Mice injected with spheroid ASCs showed improved regeneration of lung tissues, increased expression of growth factors such as fibroblast growth factor-2 (FGF2) and hepatocyte growth factor (HGF), and a reduction in proteases with an induction of protease inhibitors when compared with mice injected with dissociated ASCs. Our findings indicate that spheroid ASCs show better regeneration of lung tissues than dissociated ACSs in mice with elastase-induced emphysema.

• Development and Reproduction
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• v.21 no.4
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• pp.449-456
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• 2017

The germline stem cells of the Drosophila ovary continuously produce eggs throughout the life-span. Intricate regulation of stemness and differentiation is critical to this continuous production. The translational regulator Nos is an intrinsic factor that is required for maintenance of stemness in germline stem cells. Nos expression is reduced in differentiating cells at the post-transcriptional level by diverse translational regulators. However, molecular mechanisms underlying Nos repression are not completely understood. Through three distinct protein-protein interaction experiments, we identified specific molecular interactions between translational regulators involved in Nos repression. Our findings suggest a model in which protein complexes assemble on the 3' untranslated region of Nos mRNA in order to regulate Nos expression at the post-transcriptional level.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.613-618
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• 2001

For the evaluation of operability of MOV(Motor Operated Valve), the precision prediction of thrust/torque acting on the valve is important. In this paper, the analytical prediction method of thrust/torque was proposed. The design basis stem thrust calculation typically considers the followings: Packing thrust, Stem rejection load, design basis differential pressure load. In general, test results show that temperature, pressure, fluid type, and differential pressure, independently and combination, all have an effect on the friction factor. The prediction results of thrust/torque are well agrement with dynamic test results.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.1
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• pp.51-56
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• 2002

A recombinant transfer vector pBacSCF was constructed by inserting huamn stem cell factor (hSCF) cDNA into plasmid pBacPAK8. BmN cells were co-transfected with modified Bombyx mori, nuclear polyhedrosis virus (BmBacPAK) DNA and the recmbinant transfer vector to construct a recombinant baculovirus containing hSCE gene. DNA dot blotting and RNA dot blotting demonstrated that the hSCE gene was contained in the recombinant virus and transcribed. The recombinant baculovirus was infectious to BmN cells and to silkworm. SDS-PAGE analysis showed a specific band of expressed product in the extract of infected cells and in the heamolymph of infected larvae. Bioactivity of the recombinant hSCE was determined with W-1 cell line and MTT colorimetric method in synergy with interlukin-3 (IL-3). These results revealed that the hSCF gene was over-expressed in cultured cells and lavae of silkworm.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.18-18
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• 2002

This study was to investigate the effect of neurotrophic factors on neural cell differentiation in vitro derived from human embryonic stem (hES, MB03) cells. For neural progenitor cell formation derived from hES cells, we produced embryoid bodies (EB: for 5 days, without mitogen) from hES cells and then neurospheres (for 7 - 10 days, 20 ng/㎖ of bFGF added N2 medium) from EB. And then finally for the differentiation into mature neuron cells, neural progenitor cells were cultured in ⅰ) N2 medium (without bFGF), ⅱ) N2 supplemented with brain derived neurotrophic factor (BDNF, 5ng/㎖) or ⅲ) N2 supplemented with platelet derived growth factor-bb (PDGF-bb, 20ng/㎖) for 2 weeks. (omitted)