• 한국기계가공학회지
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• 제6권3호
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• pp.98-104
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• 2007

The carbon fiber reinforced carbon composite (CFRC) materials are necessary for the advanced industries that require the thermal resistance. And the development and research for CFRC has been in progress in the field of aerospace and defense industry. CFRC have several advantages and special properties such as excellent anti ablation, outstanding strength retention at very high temperature, high heat capacity and thermal transport, high specific stiffness and strength, and high thermal shock resistance. They have been used as aircraft brake, rocket nozzle, nose cones, jet engine turbine wheels, and high speed craft. Since the technology related to CFRC was prohibited from importing and exporting, we developed our own technology to produce F-16 B32 brake disk made out of CFRC, and then we performed various tests to observe the characteristics of CFRC-based brake disk developed in this study in view of density, strength, friction, specific heat, and heat conductivity.

• Fibers and Polymers
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• 제3권1호
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• pp.8-13
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• 2002

The effect of block sequence on the self-assembly of ABC-type triblock copolymers in the ordered state is investigated using an isothermal-isobaric molecular dynamics simulation. The block sequence has an important effect ,on the ]norphology of ABC triblock copolymers. Different morphologies are observed depending on the block sequence as well as the block composition. The triblock copolymers with the volume fraction of 1 : 1 : 1 ($f_A$=$f_B$=$f_C$= 0.33) show the three phase and four layered lamellar structures irrespective of the block sequence. The $A_{32}$$B_{16}$$C_{32}$triblock copolymer with $f_B$=0.2 shows a morphology In which cylinders of midblock B are formed at the interface between A and C lamellae, whereas the morphology of triblock copolymer $B_{16}$$C_{32}$ $A_{32}$ and $C_{32}$ $A_{32}$ $B_{16}$ show a cylindrical core-shell structure and a lamellar type morphology, respectively. The $A_{20}$$B_{40}$$C_{20}$the triblock copolymer with the block B as a major component shows a tricontinuous structure, whereas both $B_{40}$$C_{20}$$A_{20}$ and $C_{20}$$A_{20}$$B_{40}$ triblock coolymers exhibit the lamellar structures. When the block B has larger volrome fraction with $f_B$=0.75, the matrix is composed of block B, and other two blocks A and C form spherical domains.

• 한국자원식물학회지
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• 제32권4호
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• pp.275-281
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• 2019

The pathological condition of excessive melanogenesis causing freckles, melasma, senile lentigo, pigmented acne scars, and cancer has a critical impact on the wellness of individuals. The mechanism of melanogenesis is related to the expression of melanogenic enzymes. Here, we evaluated the inhibitory effect of pine cone (Pinus densiflora) extracts on melanogenesis. P. densiflora, the Korean Red Pine, is the predominant tree species in the cool, temperate forests of northeast Asia, occurring in pure stands across Korea, Japan, and parts of northern China and Russia. P. densiflora leaves, pollen, and bark have been widely used for traditional medicine, or edible purposes. However, pine cones are rarely used as natural raw materials, although they contain many bioactive phytochemicals. The pine cone ethyl acetate fraction (PEF) showed no toxicity to B16F10 cells at a concentration of less than $100{\mu}g/mL$. PEF inhibited the expression of microphthalmiaassociated transcription factor (MITF), tyrosinase and tyrosinase-related factors in B16F10 cells treated with 3-Isobutyl1-methylxanthine (IBMX). These results suggest that pine cones can be used as an effective natural melanogenesis inhibitory agent.

• KSBB Journal
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• 제32권3호
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• pp.218-233
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• 2017

To identify the natural and novel cosmeceutical ingredients which have whitening function, we examined the effects of tyrosinase activity and melanin production on halophyte Limonium tetragonum (Thunb.) A. A. Bullock extracts. As a result, the extracts showed whitening effect with no cytotoxicity. Melanin contents of B16F10 melanoma cells were decreased in a dose-dependent manner at 50, 100, $200{\mu}g/mL$ treatment of the extracts. In tyrosinase activity inhibition test, L. tetragonum (Thunb.) A. A. Bullock extracts showed decreased tyrosinase activity as the concentration of ${\alpha}-MSH$ was increased. Furthermore, it was observed that the tyrosinase and MITF expression was significantly downregulated by adding L. tetragonum (Thunb.) A. A. Bullock extracts in ${\alpha}-MSH$, a melanogenesis inducing material, treated B16F10 melanoma cells. These results indicate that L. tetragonum (Thunb.) A. A. Bullock extract might be an effective whitening agent by inhibit melanin formation.

• KSBB Journal
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• 제32권3호
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• pp.187-192
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• 2017

In this study, we investigated the effect of Rumex axetosella, Sonchus oleraceus and Euphoibia jolkini extracts on tyrosinase activity and melanin production as natural products of whitening functional cosmetics. To measure the melanin production, 50, 100, $200{\mu}g/mL$ of Rumex axetosella, Sonchus oleraceus and Euphoibia jolkini extracts were treated on ${\alpha}-MSH$ treated B16F10 melanoma cells, respectively. Melanin contents in ${\alpha}-MSH$ treated B16F10 melanoma cells were decreased by 41.5, 51.11, and 61% in $200{\mu}g/mL$ treatment compared to none treatment, respectively. In addition, the intracellular tyrosinase activity was decreased after treatments with all extracts. Furthermore, $100{\mu}g/mL$ of Euphoibia jolkini extract was decreased 81.5% of melanin production in B16F10 melanoma cells. When the three extracts were compared, Euphoibia jolkini extract was considered to be the most functional material for whitening effect.

• 생명과학회지
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• 제32권5호
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• pp.331-339
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• 2022

멜라닌은 자외선과 같은 외부자극이 가해지면 피부 기저층에 존재하는 멜라닌 세포에서 피부를 보호하기 위한 방어기전으로써 생성이 된다. 하지만 과도한 자외선 노출로 멜라닌이 필요이상으로 생성이 되면 기미, 주근깨, 검버섯과 같은 색소침착 및 색소성 피부장애를 유발할 수 있다. 최근에는 부작용이 적은 식물 추출물을 대상으로 미백소재를 찾기 위한 연구들이 활기를 띠고 있다. 이에 본 연구에서는 국내 서식 염생식물인 갯사상자 추출물을 이용하여 B16F10 흑색종 세포에서 피부 색소 멜라닌 생성 억제에 미치는 효과를 확인하였다. 갯사상자 추출물 처리시 tyrosine 및 L-DOPA 산화를 농도 의존적으로 저해하였으며 세포 내의 멜라닌 생성을 담당하는 tyrosinase, tyrosinase-related protein-1, -2 발현을 억제하였다. 이는 갯사상자 추출물이 α-MSH에 의한 세포신호 전달 경로인 GSKβ/β-catenin 및 PKA/CREB 조절에 의한 것으로 밝혀졌다. 따라서 갯사상자 추출물은 GSKβ/β-catenin 및 PKA/CREB 기전을 통해 멜라닌 합성을 억제하여 미백 효능 지닌 천연물 유래 기능성 화장품 소재로서 활용 가능할 것으로 사료된다.

• Journal of Acupuncture Research
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• 제35권4호
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• pp.182-186
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• 2018

Background: The purpose of this study was to investigate the effects of wild ginseng pharmacopuncture on melanin production in B16/F10 murine melanoma cells. Methods: To determine the effect of wild ginseng pharmacopuncture solution on B16/F10 cells, cytotoxicity was evaluated using the 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyl-tetrazolium bromide (MTT) method. To observe B16/F10 cell growth, death, and morphological changes, Trypan blue solution was used. The Hosoi method was used to investigate the effect of wild ginseng pharmacopuncture solution on melanin production. The Martinez-Esparza method was used to investigate the effect of wild ginseng pharmacopuncture solution on tyrosinase activity. To determine the pathway involved in the melanogenesis in cells exposed to wild ginseng pharmacopuncture solution, a cell-free tyrosinase was used. Results: Following treatment with $200{\mu}L$ of wild ginseng solution, the cell survival rate was $76.32{\pm}2.45%$ which significantly decreased with higher concentrations (${\mu}L$) of wild ginseng (up to $200{\mu}L$). When $100{\mu}L$ of wild ginseng was used, the cell survival rate was $89.95{\pm}2.07%$. No morphological changes or abnormalities were observed in the B16/F10 murine melanoma cells as observed in the Trypan blue test. Melanin production was significantly reduced to $72.17{\pm}3.74%$ at $100{\mu}L$. Using $100{\mu}L$ of wild ginseng solution, tyrosinase activity was significantly decreased to $80.15{\pm}1.05%$. Wild ginseng pharmacopuncture solution reduced melanin production both directly and indirectly. Conclusion: This study suggests that wild ginseng pharmacopuncture solution may be effective in inhibiting melanin production. Further studies are needed to determine safe and effective clinical applications.

• 대한본초학회지
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• 제32권2호
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• pp.57-64
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• 2017

Objectives : Yam bean (Pachyrhizus erosus) possess various nutrients, it has been widely used as traditional cosmetic material in Indonesia. The aim of this study was to investigate the anti-oxidant activity and the anti-melanogenic effect of Yambean (Pachyrhizus erosus) extract and its fractions. Methods : The anti-oxidant activity of yam bean extract assessed based on total polyphenol, flavonoid contents, DPPH and ABTS radical scavenging assay. To evaluate anti-melanogenic effects and cytotoxicity of Yambean extract and its fractions, B16F10 melanoma cell was used. Results : In results, total polyphenol content of yam bean water extract (YW) and Yambean 70% ethanol extract (YE) were $1.18{\pm}0.03mg/g$ (mg of gallic acid/g of sample), $1.16{\pm}0.01mg/g$. Total flavonoid contents of YW, YE were $3.55{\pm}0.06mg/g$ (mg of naringin/g of sample), $1.78{\pm}0.03mg/g$. Moreover, YE scavenged DPPH and ABTS effectively in $4mg/m{\ell}$ compared to YW. Cytotoxicity of YE and its fractions in B16F10 melanoma cell was measured using MTT assays. It had no cytotoxicity up to $500{\mu}g/m{\ell}$. Melanin accumulation in B16F10 melanoma cell was induced using alpha-melanocyte stimulating hormone (${\alpha}-MSH$) and 3-isobutyl-1-methylxanthine (IBMX). B16F10 melanoma cell treated with $10-500{\mu}g/m{\ell}$ YE and hexane, ethyl acetate, butanol, $H_2O$ fractions for 24h. Non treated B16F10 melanoma cell (Control) markedly increased melanin contents. In contrast, YE ethylacetate fraction effectively suppressed melanin accumulation in a dose-dependent manner. Conclusion : In conclusion, these results suggest that Yambean extract has the potential as a cosmetic material which possess anti-oxidant and anti-melanogenic activities.

• Asian-Australasian Journal of Animal Sciences
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• 제5권3호
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• pp.481-485
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• 1992

In order to upgrade native sheep, Rambouillet (R) rams were mated to Kaghani (K) ewes to generate F1 ($R{\times}K$) crossbred ewes. Crossbred ewes were backcrossed to Rambouillet rams to produce B1 ($R{\times}F1$), B2 ($R{\times}B1$) and B3 ($R{\times}B2$) genotypes. Weaning weight of 2605 lambs and wool weight of 2378 mature ewe records, representing R, K, F1, B1, B2 and B3 genotypes, were analyzed to compare genetic variation among genotypes produced during upgrading process and identify genotypes of the highest performance. Performance of Rambouillets was also evaluated under semi-temperate climate. Data were adjusted for yearly variation considering Rambouillet as a control. Genotypes influenced lambs weaning weight (p<.01). B1 lambs were heaviest (18.4 kg) followed in order by B2, F1, B3, R and K lambs (18.3, 17.9, 16.9, 16.8 and 13.2 kg, respectively). The highest wool production was 2.5 kg from R ewes followed by B2 (2.3), B3 (2.3), F1 (2.0) and K (1.2) ewes (p < .01). Ewe mating weight, reproduction, growth and wool production of Rambouillets deteriorated significantly after the first decade of their importation. Compared with the first phase (1959-1971), ewe mating weight, litter size, birth weight, lamb weaning weight and wool production declined by 20, 23, 32 and 36%, respectively, in the second phase (1972-1988).

• 대한화학회지
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• 제30권1호
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• pp.109-117
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• 1986

항암항생제 Daunorubicin(2a)합성단계의 최종물질인 7,9-Dideoxydaunomycinone (32)를 3-methoxybenzoic acid(5)로 부터 합성하였다. 3-methoxybenzoic acid를 4-methoxy-3-(phenylsulfonyl)-1(3H)-isobenzofuranone(11)으로 변형시킨 뒤 Hauser와 Rhee가 개발한 고리접합법을 이용하여 trimethoxynaphthoate 16을 얻은 후에 phenylsulfonylnaphthofuranone 22로 변화시킨 뒤 이 물질을 7-(ethylenedioxy)-2-octenoate(23)과 Michael형태의 반응을 전개시켜 anthracenoate 24를 얻었다. Anthracenoate을 tetracyclic 화합물 28로 바꾼뒤 ring B와 C에 붙은 methyl기들을 제거하여 7,9-Dideoxydaunomycinone(32)를 만들었다.