• Nuclear Engineering and Technology
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• v.35 no.2
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• pp.91-107
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• 2003

Since DBA(Design Basis Accidents) has been studied rather separately from SA(Severe Accidents) in the conventional nuclear reactor safety analysis, the thermal hydraulics during transition between DBA and SA has not been identified so much as each accident itself. Thus, in this study, the thermal hydraulic behavior from DBA to the commencement of SA has been experimentally and analytically investigated for the long-term cooling phase of LB-LOCA(Large-Break Loss-of-Coolant Accident). Experiments were conducted for both cases of the loop seal open and closed in an integral test loop, named as SNUF (Seoul National University Facility), which was scaled down to l/6.4 in length and 1/178 in area of the APR1400 (Advanced Power Reactor 1400MWe). The core mixture level was a main measured value since it took major role in the fuel heat-up rate, the location of fuel melting initiation and the channel blockage by melting material during SA. Experimental results were compared to MAAP4.03 to assess its model of calculating the core mixture level. MAAP4.03 overestimates the core two- phase mixture level because sweep-out and spill-over and the measures to simulate the status of loop seal are not included, which is against the conservatism. Thus, it is recommended that MAAP4.03 should be improved to simulate the thermal hydraulic phenomena, such as sweep-out, spill-over and the status of loop seal.

• Journal of Plant Biotechnology
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• v.30 no.4
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• pp.329-334
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• 2003

D-type cyclins are believed to regulate the G1 to S phase transition in response to nutrient and hormonal signals. We investigated the expression characteristics of the key cell-cycle regulators, mitotic and G1 cyclins in potato (Solanum tuberosum L.). We isolated D-type cyclin gene from potato and it was classified as D3 cyclin by sequence similarities and a phylogenetic analysis, and named as StcycD3;1. The accumulation of transcripts was predominantly associated with mitotically active organs, such as stolons, roots, flowers, leaves, and stems. Transcription of StcycD3;1 can be induced by sucrose.

• Journal of Nutrition and Health
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• v.47 no.1
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• pp.1-11
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• 2014

Purpose: Several studies have proven that EGCG, the primary green tea catechin, and glucosamine-6-phosphate (PGlc) reduce triglyceride contents in 3T3-L1 adipocytes. The objective of this study is to evaluate the combination effect of EGCG and PGlc on decline of accumulated fat in differentiated 3T3-L1 adipocytes. Methods: EGCG and PGlc were administered for 6 day for differentiation of 3T3-L1 adipocytes. Cell viability was measured using the CCK assay kit. In addition, TG accumulation in culture 3T3-L1 adipocytes was investigated by Oil Red O staining. We examined the expres-sion level of several genes and proteins associated with adipogenesis and lipolysis using real-time RT-PCR and Western blot analysis. A flow cytometer Calibar was used to assess the effect of EGCG and PGluco on cell-cycle progression of differentiating 3T3-L1 cells. Results: Intracelluar lipid accumulation was significantly decreased by combination treatment with EGCG $60{\mu}M$ and PGlc $200{\mu}g/m$ compared with control and EGCG treatment alone. In addition, use of combination treatment resulted in directly decreased expression of $PPAR{\gamma}$, $C/EBP{\alpha}$, and SREBP1. In addition, it inhibited adipocyte differentiation and adipogenesis through downstream regulation of adipogenic target genes such as FAS, ACSL1, and LPL, and the inhibitory action of EGCG and PGlc was found to inhibit the mitotic clonal expansion (MCE) process as evidenced by impaired cell cycle entry into S phase and the S to G2/M phase transition of confluent cells and levels of cell cycle regulating proteins such as cyclin A and CDK2. Conclusion: Combination treatment of EGCG and PGlc inhibited adipocyte differentiation through decreased expression of genes related to adipogenesis and adipogenic and cell cycle arrest in early stage of adipocyte differentiation.

• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.219-226
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• 2015

The anticancer activity of a methanolic extract from lemon leaves (MLL) was assessed in MCF-7-SC human breast cancer stem cells. MLL induced apoptosis in MCF-7-SC, as evidenced by increased apoptotic body formation, sub-G1 cell population, annexin V-positive cells, Bax/Bcl-2 ratio, as well as proteolytic activation of caspase-9 and caspase-3, and degradation of poly (ADP-ribose) polymerase (PARP) protein. Concomitantly, MLL induced the formation of acidic vesicular organelles, increased LC3-II accumulation, and reduced the activation of Akt, mTOR, and p70S6K, suggesting that MLL initiates an autophagic progression in MCF-7-SC via the Akt/mTOR pathway. Epithelial-mesenchymal transition (EMT), a critical step in the acquisition of the metastatic state, is an attractive target for therapeutic interventions directed against tumor metastasis. At low concentrations, MLL induced anti-metastatic effects on MCF-7-SC by inhibiting the EMT process. Exposure to MLL also led to an increase in the epithelial marker E-cadherin, but decreased protein levels of the mesenchymal markers Snail and Slug. Collectively, this study provides evidence that lemon leaves possess cytotoxicity and anti-metastatic properties. Therefore, MLL may prove to be beneficial as a medicinal plant for alternative novel anticancer drugs and nutraceutical products.

• Journal of Ginseng Research
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• v.35 no.1
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• pp.45-51
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• 2011

Wild ginseng has been used as a traditional medicine for thousands of years and for increase physical strength in Korea, China and Japan. This study reports that cultivated wild ginseng (CWG) inhibits adipocyte differentiation of 3T3-L1 pre-adipocytes in a concentration-dependent manner. Inhibition of adipocyte differentiation is one possible anti-obesity strategy. CWG inhibits the expression of the adipocyte differentiation regulator peroxisome proliferators-activated receptor (PPAR)${\gamma}$ and CCAAT/enhancer-binding protein ${\alpha}$mRNA. It also inhibited the expression of PPAR${\gamma}$ and adiponectin at the protein level during the differentiation of pre-adipocytes into adipocytes. Additionally, CWG blocked the cell cycle at the sub-$G_1$ phase transition, causing cells to remain in the pre-adipocyte state. These results indicate that CWG inhibits adipocyte differentiation and adipogenesis through pre-adipocyte cell cycle arrest in cultured 3T3-L1 cells.

• BMB Reports
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• v.35 no.6
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• pp.629-636
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• 2002

Protein kinase CKII (CKII) is required for progression through the cell division cycle. We recently reported that the $\beta$ subunit of protein kinase CKII ($CKII{\beta}$) associates with CKBBP1 that contains the Ring-H2 finger motif in the yeast two-hybrid system. We demonstrate here that the Ring-H2 finger-disrupted mutant of CKBBP1 does not interact with purified $CKII{\beta}$ in vitro, which shows that the Ring-H2 finger motif is critical for direct interaction with $CKII{\beta}$. The CKII holoenzyme is efficiently co-precipitated with the wild-type CKBBP1, but not with the Ring-H2 finger-disrupted CKBBP1, from whole cell extracts when epitope-tagged CKBBP1 is transiently expressed in HeLa cells. Disruption of the Ring-H2 finger motif does not affect the cellular localization of CKBBP1 in HeLa cells. The increased expression of either the wild-type CKBBP1 or Ring-H2 finger-disrupted CKBBP1 does not modulate the protein or the activity levels of CKII in HeLa cells. However, the stable expression of Ring-H2 finger-disrupted CKBBP1 in HeLa cells suppresses cell proliferation and causes the accumulation of the G1/G0 peak of the cell cycle. The Ring-H2 finger motif is required for maximal CKBBP1 phosphorylation by CKII, suggesting that the stable binding of CKBBP1 to CKII is necessary for its efficient phosphorylation. Taken together, these results suggest that the complex formation of $CKII{\beta}$ with CKBBP1 and/or CKII-mediated CKBBP1 phosphorylation is important for the G1/S phase transition of the cell cycle.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.211-217
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• 2011

Panax ginseng CA Meyer, a herb from the Araliaceae, has traditionally been used as a medicinal plant in Asian countries. Ginseng extract fermented by ginsenoside-${\beta}$-glucosidase treatment is enriched in ginsenosides such as Rh2 and Rg3. Here we show that a fermented ginseng extract, BST204, has anti-proliferative and anti-invasive effects on HT-29 human colon cancer cells. Treatment of HT-29 cells with BST204 induced cell cycle arrest at $G_1$ phase without progression to apoptosis. This cell cycle arrest was accompanied by up-regulation of tumor suppressor proteins, p53 and p21$^{WAF1/Cip1}$, down-regulation of the cyclin-dependent kinase/cyclins, Cdk2, cyclin E, and cyclin D1 involved in $G_1$ or $G_1/S$ transition, and decrease in the phosphorylated form of retinoblastoma protein. In addition, BST204 suppressed the migration of HT-29 cells induced by 12-O-tetradecanoylphorbol-13-acetate, which correlated with the inhibition of metalloproteinase-9 activity and extracellular signal-regulated kinase activity. The effects of BST204 on the proliferation and the invasiveness of HT-29 cells were similar to those of Rh2. Taken together, the results suggest that fermentation of ginseng extract with ginsenoside-${\beta}$-glucosidase enhanced the anti-proliferative and the anti-invasive activity against human colon cancer cells and these anti-tumor effects of BST204 might be mediated in part by enriched Rh2.

• Biomolecules & Therapeutics
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• v.16 no.1
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• pp.21-27
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• 2008

Clotrimazole (CLT), a potent antifungal drug, is known to inhibit tumor cell proliferation. In the present study, we examined the role of intracellular $Ca^{2+}$ in CLT-induced cell cycle arrest of colon adenocarcinoma HT29 cells. CLT inhibited growth of HT29 cells in a concentration-dependent manner, which was associated with inhibition of cell cycle progression at the G(1)-S phase transition and an increase in the expression of cell cycle inhibitor proteins p27 and p53. CLT also suppressed the $Ca^{2+}$ overload by A23187, a calcium ionophore, suggesting its role in modulation of intracellular $Ca^{2+}$ concentration in HT29 cells. The simultaneous application of CLT and A23187 with addition of $CaCl_2$ (1mM) to the medium significantly reversed CLT-induced p27 and p53 protein level increase and growth suppression. Our results suggest that CLT induces cell cycle arrest of colon adenocarcinoma HT29 cells via induction of p27 and p53, which may, at least in part, be mediated by alteration of intracellular $Ca^{2+}$ level.

• Nano
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• v.13 no.12
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• pp.1850141.1-1850141.11
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• 2018

Sodium ion batteries based on the more sodium source reserve than that of lithium have been designed as promising alternatives to lithium ion batteries. However, several problems including unsatisfied specific capacity and serious cyclic stability must be solved before the reality. One of the effective approaches to solve the abovementioned problems is to search for suitable anode materials. In this work, we designed and prepared $FeSe_2$ nanoflakes via a simple hydrothermal method which can be adjusted in composition by Fe precursor. As a potential anode for sodium storage, the optimized $FeSe_2$ electrode was further evaluated in different electrolytes of $NaClO_4$ in propylene carbonate/fluoroethylene carbonate and $NaCF_3SO_3$ in diethylene glycol dimethyl ether. The capacity was about $470mAh\;g^{-1}$ and $535mAh\;g^{-1}$ at $0.5A\;g^{-1}$, respectively, in the voltage between 0.5 V and 2.9 V in the cycle of stabilization phase. Superior performance both in capacity and in stability was obtained in ether-based electrolyte, which affords the property without plugging the intermediates of transition metal dichalcogenides during charge/discharge processes.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.61-68
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• 2021

Experiments of vertically upward steam-water two-phase flow have been carried out in single-side heated narrow rectangular channel with a gap of 3 mm. Flow patterns were identified and classified through visualization directly. Slug flow was only observed at 0.2 MPa but replaced by block-bubble flow at 1.0 MPa. Flow pattern maps at the pressure of 0.2 MPa and 1.0 MPa were plotted and the difference was analyzed. The experimental data has been compared with other flow pattern maps and transition criteria. The results show reasonable agreement with Hosler's, while a wide discrepancy is observed when compared with air-water two-phase experimental data. Current criteria developed based on air-water experiments poorly predict bubble-slug flow transition due to the different formation and growth of bubbles. This work is significant for researches on heat transfer, bubble dynamics and flow instability.