• Transactions of the KSME C: Technology and Education
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• v.2 no.1
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• pp.57-63
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• 2014

In this paper new air-cooling system utilizing Stirling engine was proposed for improving efficiency in solar photovoltaic power generation. The solar cell plate was equipped with semi-circular channel for air flow on the backside. Beta-type Stirling engine was installed on the plate and its flywheel was connected to a motor fan by a transmission belt. A forced convective air flow for heat radiation was generated by the operation of the self-starting Stirling engine. The performance tests for power generation of solar cell with or without the proposed air-cooling system were conducted under halogen lamp. From the experimental results, it was found that decline in output voltage of the solar cell with proposed cooling system was 25% less than that of the solar cell without cooling system.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1395-1399
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• 2012

Background: Histone deacetylase (HDAC) inhibitors have been reported to induce cell growth arrest, apoptosis and differentiation of tumor cells. The present study aimed to examine the effects of trichostatin A (TSA), one such inhibitor, on the cell cycle, apoptosis and invasiveness of osteosarcoma cells. Methods: MG-63 cells were treated with TSA at various concentrations. Then, cell growth and apoptosis were determined by 3-(4, 5-dimethyl-2-thiazolyl)-2H-tetrazolium bromide (MTT) and TUNEL assays, respectively; cell cycling was assessed by flow cytometry; invasion assays were performed with the transwell Boyden Chamber system. Results: MTT assays revealed that TSA significantly inhibited the growth of MG-63 cells in a concentration and time dependent manner. TSA treated cells demonstrated morphological changes indicative of apoptosis and TUNEL assays revealed increased apoptosis of MG-63 cells after TSA treatment. Flow cytometry showed that TSA arrested the cell cycle in G1/G2 phase and annexin V positive apoptotic cells increased markedly. In addition, the invasiveness of MG-63 cells was inhibited by TSA in a concentration dependent manner. Conclusion: Our findings demonstrate that TSA inhibits the proliferation, induces apoptosis and inhibits invasiveness of osteosarcoma cells in vitro. HDAC inhibitors may thus have promise to become new therapeutic agents against osteosarcoma.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.991-996
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• 2015

Side population (SP) cells have stem cell-like properties with a capacity for self-renewal and are resistant to chemotherapy and radiotherapy. Therefore the presence of SP cells in human breast cancer probably has prognostic value. Objective: To investigate the characteristics of SP cells and identify the relationship between the SP cells levels and clinico-pathological parameters of the breast tumor and disease-free survival (DFS) in breast cancer patients. Materials and Methods: A total of 122 eligible breast cancer patients were consecutively recruited from January 1, 2006 to December 31, 2007 at Yunnan Tumor Hospital. All eligible subjects received conventional treatment and were followed up for seven years. Predictors of recurrence and/or metastasis and DFS were analyzed using Cox regression analysis. Human breast cancer cells were also obtained from fresh human breast cancer tissue and cultured by the nucleic acid dye Hoechst33342 with Verapami. Flow cytometry (FCM) was employed to isolate the cells of SP and non-SP types. Results: In this study, SP cells were identified using flow cytometric analysis with Hoechst 33342 dye efflux. Adjusted for age, tumor size, lymph nodal status, histological grade, the Cox model showed a higher risk of recurrence and/or metastasis positively associated with the SP cell level (1.75, 1.02-2.98), as well as with axillary lymph node metastasis (2.99, 1.76-5.09), pathology invasiveness type (1.7, 1.14-2.55), and tumor volume doubling time (TVDT) (1.54, 1.01-2.36). Conclusions: The SP cell level is independently associated with tumor progression and clinical outcome after controlling for other pathological factors. The axillary lymph node status, TVDT and the status of non-invasive or invasive tumor independently predict the prognosis of breast cancer.

• Biomolecules & Therapeutics
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• v.27 no.1
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• pp.48-53
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• 2019

Reactive oxygen species (ROS) are widely generated in biological processes such as normal metabolism and response to xenobiotic exposure. While ROS can be beneficial or harmful to cells and tissues, generation of ROS by diverse anti-cancer drugs or phytochemicals plays an important role in the induction of apoptosis. We recently identified a derivative of naphthalene, MS-5, that induces apoptosis of an ovarian cell, CAOV-3. Interestingly, MS-5 induced apoptosis by down-regulating the ROS. Cell viability was evaluated by water-soluble tetrazolium salt (WST-1) assay. Apoptosis was evaluated by flow cytometry analysis. Intracellular ROS ($H_2O_2$), mitochondrial superoxide, mitochondrial membrane potential (MMP) and effect on cycle were determined by flow cytometry. Protein expression was assessed by western blotting. The level of ATP was measured using ATP Colorimetric/Fluorometric Assay kit. MS-5 inhibited growth of ovarian cancer cell lines, CAOV-3, in a concentration- and time-dependent manner. MS-5 also induced G1 cell cycle arrest in CAOV-3 cells, while MS-5 decreased intracellular ROS generation. In addition, cells treated with MS-5 showed the decrease in MMP and ATP production. In this study, we found that treatment with MS-5 in CAOV-3 cells induced apoptosis but decreased ROS level. We suspect that MS-5 might interfere with the minimum requirements of ROS for survival. These perturbations appear to be concentration-dependent, suggesting that MS-5 may induce apoptosis by interfering with ROS generation. We propose that MS-5 may be a potent therapeutic agent for inducing apoptosis in ovarian cancer cell through regulation of ROS.

• Clinics in Shoulder and Elbow
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• v.24 no.4
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• pp.224-230
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• 2021

Background: Local anesthetics often are used in rotator cuff tears as therapeutic tools, although some cases have reported that they have detrimental effects. Neurotropin (NTP) is used widely in Japan as a treatment for various chronic pain conditions and is shown to have protective effects on cartilage and nerve cells. In this study, we investigated the protective effect of NTP against lidocaine-induced cytotoxicity. Methods: Tenocytes from rotator cuff tendons were incubated with lidocaine, NTP, lidocaine with NTP, and a control medium. Cell viability was evaluated using the WST-8 assay. Cell apoptosis was detected via annexin V staining using flow cytometry. The expression of BCL-2 and cytochrome c, which are involved in the intrinsic mitochondrial pathway of apoptosis, was evaluated via Western blotting and immunohistochemical staining. Results: In the cell viability assay, lidocaine decreased cell viability in a dose-dependent manner, and NTP did not affect cell viability. Moreover, NTP significantly inhibited the cytotoxic effect of lidocaine. The flow cytometry analysis showed that lidocaine significantly induced apoptosis in tenocytes, and NTP considerably inhibited this lidocaine-induced apoptosis. Western blotting experiments showed that lidocaine decreased the protein expression of BCL-2, and that NTP conserved the expression of BCL-2, even when used with lidocaine. Immunohistochemical staining for cytochrome c showed that 0.1% lidocaine increased cytochrome c-positive cells, and NTP suppressed lidocaine-induced cytochrome c expression. Conclusions: NTP suppresses lidocaine-induced apoptosis of tenocytes by inhibiting the mitochondrial apoptotic pathway. Intra-articular/bursal injection of NTP with lidocaine could protect tenocytes in rotator cuff tendons against lidocaine-induced apoptosis.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.263-270
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• 2009

Carbon felt surface was modified by heat or acid treatment in order to use for the electrode of a redox-flow battery. Polymers on the surface of carbon felt was removed and oxygen-containing functional group was attached after the thermal treatment of carbon felt. Thermal treatment was better for the stability of the carbon structure than the acid treatment. Oxygen-containing functional group on the thermally treated carbon felt at 500$^{\circ}C$ was confirmed by XPS and elementary analysis. BET surface area was increased from nearly zero to 96 $m^2/g$. Thermally treated carbon felt at 500$^{\circ}C$ showed lower activation polarization than the thermally treated carbon felt at 400$^{\circ}C$ and the acid-treated carbon felt in the cyclicvoltammetry and polarization experiments. The thermally treated carbon felts at 400$^{\circ}C$ and 500$^{\circ}C$ and the acid-treated carbon felt was applied for the electrode to prepare vanadium redox flow battery. Voltage efficiencies of charge/discharge were 86.6%, 89.6%, and 96.9% for the thermally treated carbon felts at 400$^{\circ}C$ and 500$^{\circ}C$ and the acid-treated carbon felt, respectively.

• Reproductive and Developmental Biology
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• v.29 no.2
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• pp.109-115
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• 2005

Hematopoietic stem cells (HSC) are multipotent cells that reside in the bone marrow and replenish all adult hematopoietic lineages throughoutthe lifetime. In this study, we analyzed the expression of receptors of $P2Y_{10}$, purinergic receptor families in murine hematopoietic stem cells, hematopoietic progenitor cells. In addition, the biological activity of $P2Y_{10}$ was investigated with B lymphocyte cell line, Ba/F3 in effect to cell growth and cell cycle. From the analysis of expression in hematopoieticstem cell. and progenitor with RT-PCR, $P2Y_{10}$ was strongly expressed in murine hematopoieticstem cells (c-kit+ Sca-l+ Lin-) and progenitor cell population, such as c-kit- Sca-l+ Lin-, c-kit+ Sca-l- Lin- and c-kit- Sca-l- Lin-. To investigate the biological effects by $P2Y_{10}$, retroviral vector from subcloned murine $P2Y_{10}$ cDNA was used fur gene introduction into Ba/F3 cells, and stable transfectant cells were obtained by flow cytometry sorting. In cell proliferation assay, the proliferation ability of $P2Y_{10}$ receptor gene­transfected cells was strongly inhibited, and the cell cycle was arrested at G1 phase. These result suggest that the $P2Y_{10}$ may be involved the biological activity in hematopoietic stem cells and immature B lymphocytes.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.3
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• pp.1-12
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• 2006

Purpose : This study was aimed to investigate the inhibitory effect of Leonurus sibiricus on the proliferation of human uterine leiomyoma cells and the expression of gene related the mechanism of cell apoptosis. Methods : We counted the number of death cells treated with indicated concentration of Leonurus sibiricus and investigated cell death rate by MTS assay. Furthermore, flow cytometry analysis and DNA fragmentation assay were used to dissect between necrosis and apoptosis and then we observed the differential gene expression by western blot analysis. Results : Leonurus sibiricus significantly inhibited the proliferation of uterine leiomyoma cell in a dose-dependent and time dependent manner. Fluorescence activated cell sorter (FACS) analysis indicated that Leonurus sibiricus induced G1 cell cycle arrest. Leonurus sibiricus enhanced the expression of p27 and p53 with cell cycle arrest. Conclusion : These findings suggest that Leonurus sibiricus is a candidate agent for the treatment of uterine leiomyoma. p27, $p53^{1}$ may play an important role in Leonurus sibiricus-induced cell cycle arrest and cell growth inhibition.

• International Journal of Automotive Technology
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• v.8 no.1
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• pp.119-126
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• 2007

Because of the low temperature operation, proton exchange membrane (PEM) fuel cell has a water phase transition. Therefore, water management is an important operation issue in a PEM fuel cell because the liquid water in the fuel cell causes electrode flooding that can lower the cell performance under high current density conditions. In this study, in order to understand the reactant distributions in the cathode channels of the PEM fuel cell, an experimental technique that can measure the species concentrations of reactant gases by using gas chromatograph (GC) is applied for an operating PEM fuel cell. The oxygen distribution along the cathode flow channels of PEM fuel cell is mainly investigated with various operating conditions. Also, the relations between cathode flooding and oxygen concentrations and oxygen consumption pattern along the cathode channel configurations of the unit cell adopted for this study are discussed using GC measurement and visualization experiment of cathode flooding. It is found that the amount of oxygen consumption is very sensitive to various operating conditions of the fuel cell and was much affected by the flooding occurrence in cathode channels.

• The Journal of Internal Korean Medicine
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• v.26 no.1
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• pp.60-73
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• 2005

Objectives : The aim of this study was to evaluate the effects of Loranthus parasiticus Merr. on cell cycle and expression of related genes in HepG2 cells. Methods : The MTT assay, cell counting assay, $[^3H]-Thymidine$ incorporation assay, flow cytometric analysis, quantitative RT-PCR and western blot assay were studied. Results : In the water extract of Loranthus parasiticus Merr., inhibition of cell proliferation and DNA synthesis in HepG2 cells was seen. These inhibitory effects were due to inhibition of G l-S transition in cell cycle. After treatment with the extract, expression of cyclin D1(G1 check point related gene) was inhibited particularly in dose-dependent and time-dependent manners. Conclusion : These results suggest that the inhibition of cell cycle progression by Loranthus parasiticus Merr. in HepG2 cell is due to suppression of cyclin D1(G1 check point related gene) mRNA expression and protein synthesis.