• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.4
• /
• pp.406-413
• /
• 2011

Recently the fuel cell has been spotlighted as a technology to reduce greenhouse gases emission from a ship. In this research, internal reforming 500kW solid oxide fuel cell stacks fueled by methane for a ship were developed. Characteristics of power and efficiency depending on the number of cells in the stack, hydrogen conversion ratio, and active area of the cell are evaluated. Also the effects of air and methane supplying conditions on performance are analyzed. As a result, as the number of cells, hydrogen conversion ratio, active area of the cell, or supplied air flow rate increase, the stack power and efficiency increase. When the methane flow rate increases, the power increases. However the efficiency decreases. In addition, the case at the current of 976.4 A, voltage of 529.1 V, with corresponding power of 516.6 kW shows that the efficiency of fuel cell stack is 42.91%.

• The Korean Journal of Physiology and Pharmacology
• /
• v.24 no.3
• /
• pp.223-232
• /
• 2020

Sesamin, a lipid-soluble lignin originally isolated from sesame seeds, which induces cancer cell apoptosis and autophagy. In the present study, has been reported that sesamin induces apoptosis via several pathways in human lung cancer cells. However, whether mitophagy is involved in sesamin induced lung cancer cell apotosis remains unclear. This study, the anticancer activity of sesamin in lung cancer was studied by reactive oxygen species (ROS) and mitophagy. A549 cells were treated with sesamin, and cell viability, migration ability, and cell cycle were assessed using the CCK8 assay, scratch-wound test, and flow cytometry, respectively. ROS levels, mitochondrial membrane potential, and apoptosis were examined by flow cytometric detection of DCFH-DA fluorescence and by using JC-1 and TUNEL assays. The results indicated that sesamin treatment inhibited the cell viability and migration ability of A549 cells and induced G₀/G₁ phase arrest. Furthermore, sesamin induced an increase in ROS levels, a reduction in mitochondrial membrane potential, and apoptosis accompanied by an increase in cleaved caspase-3 and cleaved caspase-9. Additionally, sesamin triggered mitophagy and increased the expression of PINK1 and translocation of Parkin from the cytoplasm to the mitochondria. However, the antioxidant N-acetyl-L-cysteine clearly reduced the oxidative stress and mitophagy induced by sesamin. Furthermore, we found that cyclosporine A (an inhibitor of mitophagy) decreased the inhibitory effect of sesamin on A549 cell viability. Collectively, our data indicate that sesamin exerts lethal effects on lung cancer cells through the induction of ROS-mediated mitophagy and mitochondrial apoptosis.

• Archives of Pharmacal Research
• /
• v.20 no.4
• /
• pp.297-305
• /
• 1997

A new serum-free defined medium was developed that supports the growth of normal rat mammary epithelial cells. Mammary organoids from the glands of female F344 rats were cultured in a serum-free medium. Monolayer culture colonies developed within a week and remained viable for months in culture. Upon subculture of one-week-old primary colonies, almost the same morphology of colonies was developed. The scrape loading/dye transfer technique showed that most of colonies that developed in a serum-free medium containing EGF, human transferrin, insulin, and hydrocortisone (basal serum-free medium, BSFM) failed to show cell-cell communication. However, colonies cultured in BSFM supplemented with prolactin, $E_2$, and progesterone (complete hormone serum-free medium, CHSFM) showed cell-cell communication at 14 days of primary culture or of subculture. By flow cytometry with FITCPNA and PE-anti-Thy-1.1 monoclonal antibody, we distinguished four RMEC subpopulations in cultures in both media: Thy-1.1+ cells, PNA+ cells, cells negative to both reagents and cells positive to both reagents. It is likely that combined prolactin, cortisol, and insulin in CHSFM stimulate terminal differentiation of clonogenic cells.

• Biomolecules & Therapeutics
• /
• v.26 no.3
• /
• pp.328-334
• /
• 2018

Because of the unsatisfactory treatment options for breast cancer (BC), there is a need to develop novel therapeutic approaches for this malignancy. One such strategy is chemotherapy using non-toxic dietary substances and botanical products. Studies have shown that Panduratin A (PA) possesses many health benefits, including anti-inflammatory, anti-bacterial, anti-oxidant and anticancer activities. In the present study, we provide evidence that PA treatment of MCF-7 BC cells resulted in a time- and dose-dependent inhibition of cell growth with an $IC_{50}$ of $15{\mu}M$ and no to little effect on normal human MCF-10A breast cells. To define the mechanism of these anti-proliferative effects of PA, we determined its effect critical molecular events known to regulate the cell cycle and apoptotic machinery. Immunofluorescence and flow cytometric analysis of Annexin V-FITC staining provided evidence for the induction of apoptosis. PA treatment of BC cells resulted in increased activity/expression of mitochondrial cytochrome C, caspases 7, 8 and 9 with a significant increase in the Bax:Bcl-2 ratio, suggesting the involvement of a mitochondrial-dependent apoptotic pathway. Furthermore, cell cycle analysis using flow cytometry showed that PA treatment of cells resulted in G0/G1 arrest in a dose-dependent manner. Immunoblot analysis data revealed that, in MCF-7 cell lines, PA treatment resulted in the dose-dependent (i) induction of $p21^{WAF1/Cip1}$ and p27Kip1, (ii) downregulation of Cyclin dependent kinase (CDK) 4 and (iii) decrease in cyclin D1. These findings suggest that PA may be an effective therapeutic agent against BC.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.9
• /
• pp.5513-5518
• /
• 2013

IFN-${\gamma}$ plays an indirect anti-cancer role through the immune system but may have direct negative effects on cancer cells. It regulates the viability of gastric cancer cells, so we examined whether it affects their proliferation and how that might be brought about. We exposed AGS, HGC-27 and GES-1 gastric cancer cell lines to IFN-${\gamma}$ and found significantly reduced colony formation ability. Flow cytometry revealed no effect of IFN-${\gamma}$ on apoptosis of cell lines and no effect on cell aging as assessed by ${\beta}$-gal staining. Microarray assay revealed that IFN-${\gamma}$ changed the mRNA expression of genes related to the cell cycle and cell proliferation and migration, as well as chemokines and chemokine receptors, and immunity-related genes. Finally, flow cytometry revealed that IFN-${\gamma}$ arrested the cells in the G1/S phase. IFN-${\gamma}$ may slow proliferation of some gastric cancer cells by affecting the cell cycle to play a negative role in the development of gastric cancer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.3
• /
• pp.209-213
• /
• 2001

Treatment of oral cancers with chemotherapeutic agents are evaluated as an effective method for remission to reduce cancer proliferation nowadays. But, minimization of side-effects such as bone marrow suppression, gastrointestinal toxicity and renal damage is another problem to be solved. Thus, a possible approach to develop a clinically applicable chemotherapeutic agents is to screen anticancer activity among traditional medicinal plants which have been used for thousands of years with very low side-effects in orient. In this study we focused on anti-oral cancer activities of momordin, which was medicinal plant extracts that was revealed anticancer activities, on KB cell(oral cancer cell). The results were as follow : 1. Momordin showed the excellent anti-oral cancer activity against KB cells. Obtained IC50 value of Momordin was $10.4{\mu}g/ml$. 2. When KB cells were treated with Momordin, dose and time dependent DNA fragmentation of KB cells were observed. DNA fragmentation was initiated on three days at the concentration of $20{\mu}g/ml$ Momordin. 3. Flow cytometry showed dose-dependent apoptotic cell increase of KB cells on Momordin. 18.55% apoptotic cell were observed up to 72 hours at the concentration of $20{\mu}g/ml$ of Momordin. 4. Momordin induced nonspecific apoptosis without specific cell cycle arrest. 5. Through MTT assay, DNA fragmentation assay and flow cytometric analysis. anticancer effect of Momordin against KB cell was induce of apoptotic cell death.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.13 no.6
• /
• pp.469-475
• /
• 2008

In this paper, control of small PEM(Proton Exchange Membrane) fuel cell stack by a microprocessor is introduced. The water management of fuel cell stack inside, a key technique in fuel cell control, can be achieved by adjusting the required air flow for fuel and cooling, and by purging the excessive water from the stack. It is very important to precisely control the BOS(Balance of Stack) since the stable operation of the fuel cell system mainly depends on it. In this study the fuel efficiency of the system is improved by the control of the system based on the measured air flow and purge cycle during the optimal operation and its effectiveness is proved by the experiments. The operating stability of the system is improved by the developed controller using a microprocessor and it is expected to be widely used for the control of small PEM fuel cell stack.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1991.11a
• /
• pp.160-164
• /
• 1991

The effect of various parameters, such as temperature, current density and operating valtage on the performance of phosphoric acid fuel cell stack was studied by using numerical analysis. The utilization ratio of reaction gas, inlet condition of reaction air and cooling air, inlet condition of cooling air flow latin were changed regularly, The results showed good agreements with the existing results and experimental ones.

• New & Renewable Energy
• /
• v.2 no.4 s.8
• /
• pp.78-85
• /
• 2006

Selection of flow channel in the separation plate of PEMFC is very important parameter to improve its performance and reduce parasite loss. Flow patterns in the channel have great influence on the transport of hydrogen and air and removal of water generated from electrochemical reaction in diffusion layer. In this study. fluid flow in flow channel with parallel and interdigitated patterns are simulated three dimensionally on full flow domain including anode and cathode channel together. The numerical results show that the fuel cell with interdigitated flow channel represents better performance than that with parallel flow channel due to its strong convective transport across the gas diffusion layer. But the pressure drop in parallel flow channel is much more than that in interdigitated flow channel. And effects of temperature and stoichiometric number on performance can be calculated and analyzed as well. Nomenclature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.18 no.10
• /
• pp.819-825
• /
• 2006

In a SOFC/GT (solid oxide fuel cell/gas turbine) hybrid power generation system, the recuperator is an indispensible component to enhance system performance. Since the expansion ratio to the recuperator core is very large, generally, the effective header design to distribute the flow uniformly before entering the core is crucial to guarantee the required performance. In the present study, we focus on the design of a diffuser type recuperator header with a 90 degree turn inlet port. To reduce the flow separation and recirculation flows, multiple horizontal vanes are used. The number of horizontal vanes is varied from 0 to 24. The air flow velocity is measured at 40 points just behind the core outlet by using a hot wire anemometer. Then, the flow non-uniformity is evaluated from the measured flow velocity. The experimental results showed that inlet air velocity did not effect on relative flow non-uniformity. According to increasing the number of horizontal vanes, flow non-uniformity reduced about $40{\sim}50%$ than without using horizontal vanes.