• Journal of Korean Society for Quality Management
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• v.38 no.3
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• pp.333-339
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• 2010

It is difficult to determine an optimal inventory level of aircraft engine and modules to achieve the target operational availability since F100-PW-200 & 229 engines of the F-16 & KF-16 aircraft are consisted of 5 modules with different failure rates and costs. This study presents a decision model, combining an integer programming problem and a regression metamodel. Data for the metamodel was attained from results of a simulation model, that represents operational and repair process of F-16 and KF-16. The objective function of an integer programming problem is maximizing the operational availability, representing pessimistic circumstances. Finally, an integer programming problem with a metamodel can make an optimal decision of the inventory level.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.136.2-137
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• 2003

In order to diagnose and differentiate jujube witches' broom (JWB) phytoplasma rapidly, oligonucleotide primer pair, 16Sr(V) F/R, for polymerase chain reactions (PCRs) was designed on the basis of 165 rRNA sequences of JWB phytoplasma. The PCR employing phytoplasma universal primer pair P1/P7 consistently amplified DNA in all tested phytoplasma isolates. But no phytoplasma DNA was detected in healthy jujube seedlings. The nested PCR, the primer pair 16S(V) F/R, about 460 bp fragment, amplified DNA in all tested JWB and related phytoplasmas including LiWB phytoplasma of the 165 rRNA group V, but no DNA amplification was detected from other phytoplasma strains such as group 16SrI (Aster yellows) and group 16SrⅩII (Stolbur group) phytoplasmas in which mulberry dwarf phytoplasma and chrysanthemum witches broom phytoplasma are belonged to, respectively The same results were obtained from both Korean- and Chinese-isolates of JWB. Nested-PCR using phytoplasma universal primer pair P1/P7 and 16S rRNA group V specific primer pair 16S(V) F/R could detect group V phytoplasma rapidly and easily, in particular JWB phytoplasma.

• Corrosion Science and Technology
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• v.16 no.1
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• pp.48-48
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• 2017

• Defense and Technology
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• no.4 s.230
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• pp.22-29
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• 1998

현재 개발이 완료되고 비행시험이 진행중인 FS-X의 개발기간중 FS-X의 운용요구라면 기존의 미국 전투기인 F-15, F-16 또는 F/A-18을 재설계하거나 개조하면 충분히 만족할 수 있고 적은 비용으로 획득할 수 있다는 미국의 주장에 대항한 일본의 대응책과 기술개발력 육성의 문제를 일본의 안전보장이라는 관점에서 정리함으로써 향후 한국의 항공산업 발전에 참고가 되었으면 한다

• Journal of The Korean Astronomical Society
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• v.3 no.1
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• pp.13-16
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• 1970

A hyperbolic orbit is expanded in terms of F analogous to the eccentric anomaly of an elliptical orbit: ${\tau}^p\;sinq{\upsilon}\;and\;{\tau}^p\;cosq{\upsilon}$ are expressed in terms of F. The true anomaly ${\upsilon}$ is expressed in terms of F, and F in terms of ${\upsilon}$.

• Defense and Technology
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• no.5 s.231
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• pp.26-33
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• 1998

현재 개발이 완료되고 비행시험이 진행중인 FS-X의 개발기간중, FS-X의 운용요구라면 기존의 미국 전투기인 F-15, F-16 또는 F/A-18을 재설계하거나 개조하면 충분히 만족할 수 있고 적은 비용으로 획득할 수 있다는 미국의 주장에 대항한 일본의 대응책과 기술개발력 육성의 문제를 일본의 안전보장이라는 관점에서 정리함으로써 향후 한국의 항공산업 발전에 참고가 되었으면 한다.

• Journal of Life Science
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• v.20 no.11
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• pp.1617-1624
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• 2010

Recently, it has been found that Asiasari radix showed a hypopigmenting effect on melanogenesis through activation of mitogen-activated protein kinase (MEK)/extracellular signal-activated kinase (ERK) in B16F10 melanoma cells. However, the hypopigmenting effect of A. radix on the $\alpha$-melanocyte stimulating hormone ($\alpha$-MSH)-stimulated melanogenesis has remained unknown. The purpose of this study was to investigate the inhibitory mechanism of the partially purified A. radix (PPAR)-induced hypopigmentating effects on $\alpha$-MSH-stimulated melanogenesis in B16F10 mouse melanoma cells. PPAR strongly inhibited tyrosinase activity and leads to decreased melanin synthesis in $\alpha$-MSH-stimulated B16F10 melanoma cells. PPAR also decreased the $\alpha$-MSH-induced over-expression of the melanogenic enzymes, tyrosinase, tyrosinase-related protein (TRP)-1, dopachrome tautomerase (Dct) and microphthalmia-associated transcription factor (MITF). We further showed that PPAR inhibits $\alpha$-MSH-induced melanogenesis via phosphorylation of MEK/ERK and PI3K/Akt, and that their activation was blocked by MEK inhibitors, PD98059 and PI3K inhibitors, LY294002 in $\alpha$-MSH-stimulated B16F10 melanoma cells. These results suggest that PPAR inhibits $\alpha$-MSH-induced melanogenesis by activation of MEK/ERK and PI3K/Akt through MITF degradation, which may lead to down-regulation of tyrosinase.

• Journal of Life Science
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• v.29 no.9
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• pp.972-976
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• 2019

Polyopes affinis is a kind of red algae found in the South coast and near Jeju Island of Korea. The purpose of this study was to investigate the effects of Polyopes affinis ethanol extract (PAEE) on melanogenesis in ${\alpha}-MSH$ stimulated B16F10 melanoma cells. Melanoma cells were cultured for 72 hr treated with PAEE. Total melanin content and the activity of tyrosinase, a key enzyme in melanogenesis, were measured. When the melanin content in B16F10 melanoma cells was tested, PAEE was decreased in a dose-dependent manner: treatment with 100, 300, and $500{\mu}g/ml$ caused 25%, 30%, and 35% reduction, respectively. Treatment of 100, 300, and $500{\mu}g/ml$ of PAEE caused 6%, 12%, and 21% reduction of tyrosinase activities in B16F10 melanoma cells. Also, PAEE suppressed the expression of tyrosinase, tyrosinase-related protein-1, tyrosinase-related protein-2, and melanocyte-inducing transcription factor in B16F10 melanoma cells. A concentration of $500{\mu}g/ml$ of PAEE showed a greater decrease in tyrosinase activity, melanin content, and melanogenic enzyme protein expression. These results indicate that PAEE inhibits melanin synthesis and tyrosinase activity, and Polyopes affinis ethanol extract could be used as a functional whitening agent.

• YAKHAK HOEJI
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• v.51 no.5
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• pp.350-354
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• 2007

Taurine has been shown to be tissue-protective against oxidant-induced injury and is a powerful regulator of the immune system. However, there is no study on the antimelanogenic effect of taurine. In this study, we investigated the whitening effect of taurine in B16F10 mouse melanoma cells. Cell viability was measured by MTT assay. We examined melanin contents and tyrosinase activity according to time and concentration. Extracellular signal regulated kinase (ERK) is an important regulator of melanogenesis. It has been reported that activated ERK induced microphthalmia associated transcription factor (MITF) phosphorylation and its subsequent degradation and thus reduced melanin synthesis. In our B16F10 cell culture system, taurine led to decrease melanin contents by 21% at 48 hr. We then observed taurine effects on ERK-P, MITF and tyrosinase by Western blot. ERK was activated at 18 hr and 24 hr, whereas MITF reduced. We could not observe any differences in the levels of tyrosinase. These results suggested that taurine inhibited melanogenesis by ERK signal pathway via MITF degradation. We expect that taurine has potential skin whitening agents in cosmetics.

• YAKHAK HOEJI
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• v.46 no.2
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• pp.137-142
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• 2002

Caesalpinia sappan L. has long been commonly used as emmenagogue, analgesic, and a cure for contusion and sprain as well as a remedy for thrombosis in the Oriental medicine. The main constituent of C. sappan is brazilein, which is an antioxidative substance that has a flavonoid structure. In this study, we examined the effect of butanol extract of C. sappan on proliferation and melanogenesis in B16/F10 melanoma cells. After 48h treatment of cells with various concentrations of butanol extract, the cells exhibited a dose-dependent inhibition in their proliferation without apotosis. Therefore, the growth retardation by the extract may be due to the cell arrest, not due to the cell death induced by cytotoxicity. We also estimated total melanin contents as a final product and activity of tyrosinase, a key enzyme, in melanogenesis of B16/F10 melanoma cells. Our result showed that the melanin contents and tyrosinase activity were decreased in butanol extract-treated cells in a dose dependent manner compared to control group. In conclusion, it was observed that butanol extract of C. sappan inhibited melanization of these cells and therefore butanol extract could be developed as skin whitening components of cosmetics.