• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.778-782
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• 2012

Until a recent day, degradation of PEMFC MEA (membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. Therefore in this work, AST (Accelerated Stress Test) of MEA degradation was done at the condition that membrane and electrode were degraded simultaneously. There was interaction between membrane degradation and electrode degradation. Membrane degradation reduced the decrease range of catalyst active area by electrode degradation. Electrode degradation reduces increase range of the hydrogen crossover current and FER (Fluoride Emission Rate) by membrane degradation.

• Journal of Hydrogen and New Energy
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• v.25 no.3
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• pp.264-270
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• 2014

Fuel cell technology is the most representative area of alternative energy field on vehicle industry according to the limitation of petroleum resources. In recent years, the technology of fuel cell vehicles has made rapid progress, Hyundai Motor Company (HMC) reached to mass production of the Tucson ix hydrogen fuel cell vehicles first in the world. In addition, HMC is accelerating the development of hydrogen fuel cell buses, which have a number of advantages for hydrogen infrastructure and mass transport personnel. In this study, we examined potential of the commercialization through the demonstration of hydrogen fuel cell buses. As a result, we identified that the mass-production possibility of FCB has high potential and HMC's technology will lead to fuel cell bus industry.

• Natural Product Sciences
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• v.10 no.5
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• pp.211-216
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• 2004

Citrus unshiu (Rutaceae) has long been known as an anti-inflammatory and anti-allergic agent. In the present study, the inhibitory effect of CUWE (Citus unshiu water extract) on the production of $TNF-{\alpha}$ and tryptase was examined. In addition, a possible mechanism for the inhibition of trypsin-stimulated human leukemic mast cell-1 (HMC- 1 ) activation was determined. To do so, $TNF-{\alpha}$ production from the HMC-1 cells that were stimulated by trypsin (100 nM) in the presence or absence of CUWE $(10,\;100,\;and\;100\;{\mu}g/ml)$ was measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-PCR. The tryptase production was evaluated by reverse transcription-PCR. Extracellular signal-regulated kinase (ERK) activation was analyzed by Western blot. Trypsin activity was measured by using Bz-DL-Arg-p-nitroanilide (BAPNA) as substrate. Results showed that the CUWE inhibited production of both $TNF-{\alpha}$ and tryptase from the trypsin-stimulated HMC-1 in a dose-dependent manner. The CUWE a1so inhibited the ERK phosphorylation and trysin activity. These results indicate that the CUWE had an inhibitory effect on $TNF-{\alpha}$ and the tryptase productions by blocking the ERK phosphorylation and trypsin activity.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.12-18
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• 2014

This paper describes about the development of new concept's rear wheel guards for the reduction of Road Noise in the passenger vehicle using test. The new wheel guards are proposed by various frequency chamber concept and different textile layers concept. Two wheel guards were verified by small cabin resonance test and vehicle test. Through new developing process without vehicle test, Result of road noise will be expected when new concepts and materials of wheel guard is applied into automotive vehicle. As a result of the application of Aimed Helmholtz and Multi-layers concept, this paper classifies the road noise, cost and weight are reduced by new concepts and the solutions are adopted into the 2 cars.

• Advances in Traditional Medicine
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• v.9 no.2
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• pp.149-156
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• 2009

Equisetum hyemale Linne. (EH) (Equisetaceae) has been used for the treatment of eye and skin disease, chronic eczema, pneumoconiosis and asthma in Korea and China. Human leukemic mast cells are widely distributed in the connective tissues of mammals and other vertebrates. Phorbol 12-myristrate 13-acetate (PMA) and calcium ionophore A23187 stimulated Human leukaemic mast cell line-1 (HMC-1) can produce a variety of inflammatory mediators and several pro-inflammatory and chemotactic cytokines such as TNF-$\alpha$, IL-6 and IL-8. Since TNF-$\alpha$, IL-6 and IL-8 are major factors during the inflammatory process, we studied the effects of EH on TNF-$\alpha$, IL-6 and IL-8 release in HMC-1 stimulated with PMA and A23187. The result of this study indicate that EH inhibits TNF-$\alpha$, IL-6 and IL-8 in activated HMC-1 cells via $I{\kappa}B$/Nuclear factor-${\kappa}B$ pathway. Therefore, EH might contribute significantly to the prevention or treatment of mast-cell mediated inflammatory diseases and EH has potential use in the therapy of chronic allergic inflammation.

• Natural Product Sciences
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• v.13 no.2
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• pp.169-173
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• 2007

Luteolin is a major flavonoid of Lonicera japonica and has anti-inflammatory effect. The activation of proteinase-activated receptor (PAR)-2 and -4 by trypsin appears to play a role in inflammation, In the present study, we examined the inhibitory effects of luteolin on activation of trypsin-induced human leukemic mast cells (HMC-1). HMC-1 cells were stimulated with trypsin, PAR-2 and PAR-4 agonist, in the presence or absence of luteolin. The level of TNF-${\alpha}$ secretion was measured by enzyme-linked immunosorbent assay (ELISA). The expression of tryptase and phosphorylated-extracellular signal-regulated kinase (ERK) were assessed by Westem blot analysis. Moreover, trypsin activity was measured by the substrate Bz-DL-Arg-p-nitroanilide (BAPNA). TNF-${\alpha}$ secretion and Tryptase expression in trypsin-stimulated HMC-1 cells were markedly inhibited by pretreatment of luteolin. Furthermore, the pretreatment of luteolin resulted in the reduction of ERK phosphorylation and trypsin activity. These results suggest that luteolin might has the inhibitory effects on the PAR-2 and -4-dependent inflammation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.123-123
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• 2019

Xanthone is a kind of polyphenolic compounds that contain a distinctive chemical structure with a tricyclic aromatic ring found in a few higher plant families e.g. gentian root. This compound had a variety of biological activity, for instance antioxidant, antibacterial, anti-inflammatory, and anticancer effects. However, the effect of xanthone on mast cell-mediated allergic inflammation and its associated mechanism have not been elucidated. Therefore, the aim of this study was to elucidate the anti-allergic inflammatory effects and the underlying molecular mechanism of xanthone in PMACI-stimulated human mast cells-1 (HMC-1). In this result, xanthone treatment decreased the production of histamine, pro-inflammatory cytokines such as tumor necrosis factor-a (TNF-${\alpha}$), IL-6, and IL-8 and expressions of TSLP in PMACI-stimulated HMC-cells. In addition, xanthone significantly suppressed the phosphorylation of MAPKs and the activation of NF-${\kappa}B$ signal pathway in activated mast cells. Furthermore, xanthone inhibited the activation of caspase-1, an IL-$1{\beta}$ converting enzyme, in PMACI-stimulated HMC-1 cells. These findings provide evidence that xanthone could be a potential therapeutic agent for allergy-related inflammatory disorders.

• The Journal of Internal Korean Medicine
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• v.25 no.4
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• pp.289-299
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• 2004

Background : Although the pathophysiology of asthma has been reported, its mechanism has not been fully elucidated. The mast cell is an effector cells in allergic inflammation and secretes a number of chemokines. Chemokines are important for the recruitment of leukocytes to sites of infection, which is essential in host defense. Chemokines also contribute to the pathogenesis of several disorders such as asthma, chronic bronchitis, atopic dermatitis, allergic rhinitis, and rheumatoid arthritis. Objective : In this study, the aim was to identify the effect of Baekryunchihyo-tang(白蓮治哮湯) on expression of chemokines. This was examined by RT-PCR using the human mast cell line (HMC-l) Materials and Methods : HMC-l cells were used, which is known to secrete and express chemokines. In order to investigate the protective effect of Baekryunchihyo-tang(白蓮治哮湯), HMC-l cells were incubated with pretreatment of Baekryunchihyo-tang(白蓮治哮湯) for 24 hrs. RT-PCR analyses of chemokine genes of cells pretreated with Baekryunchihyo-tang(白蓮治哮湯) showed that expressions of IL-8, $MIP-l{\beta}$, and RANTES genes in these cells were lower and $MIP-l{\alpha}$ showed a similar pattern compared to the calcium ionophore-treated group. In addition, cell cytotoxicity concentration measurements were performed by MTT assay method. Results : After stimulation with 1 uM calcium ionophore A23178 for 2 hrs, IL-8, major one of CXC chemokines, was highly expressed, and expression of $MIP-l{\beta}$ and RANTES (CC chemokines) increased, while expression of $MIP-l{\alpha}$ did not change. The cell cytotoxicity of Baekryunchihyo-tang(白蓮治哮湯) with treatments at various concentrations and times was not observed, respectively. Conclusion : This study suggests that Baekryunchihyo-tang(白蓮治哮湯) has dose-dependent effects on mRNA expression of IL-8(CXC chemokines), $MIP-l{\beta}$ and RANTES(CC chemokines) in human mast cellline(HMC-l). So these herbal medicines may inhibit the inflammatory process of asthma. Advanced studies are required to investigate the mechanism of inhibition by herbal medicine in the asthma model. This study provides basic data on the possibility of the clinical treatment of Baekryunchihyo-tang(白蓮治哮湯) for allergic disorders.

• Journal of Life Science
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• v.19 no.12
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• pp.1808-1814
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• 2009

In our previous study, a new herbal preparation (HemoHIM) was developed as a functional food for the radioprotection and immunomodulatory agents. In order elucidate the mechanism involved, we examined the effect of HemoHIM on the compound 48/80-induced histamine release, and on the phorbol 12-myristate 13-acetate (PMA)/calcium ionophore (A23187)-induced inflammatory cytokine secretion in HMC-1. The cell culture supernatants were harvested, and the cytokines (IL-4, IL-6, IL-8, TNF-$\alpha$, GM-CSF) in the supernatants were measured by enzyme-linked immunosorbent assay. The total RNA of the cells was extracted, and the cytokines or c-kit/tryptase/Fc$\varepsilon$RI's messenger RNA expressions were examined using reverse transcriptase polymerase chain reaction. Under low concentrations, HemoHIM inhibited histamine release in HMC-1 stimulated compound 48/80. Furthermore HemoHIM inhibited PMA/A23187-induced inflammatory cytokines' secreation or mRNA expression in a dose-dependent manner. But IL-8 secretion was not inhibited by low concentrayion of HemoHIM, respectively. The mRNA expression of c-kit and Fc$\varepsilon$RI were also inhibited in a dose-dependent manner. Tryptase mRNA expression was only inhibited by low concentration of HemoHIM. These results indicated that HemoHIM might be an useful agent for protection against allergy as well as immune modulation, especially since it is a relatively nontoxic natural product.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10a
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• pp.65-74
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• 2002