• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.37 no.3
• /
• pp.275-282
• /
• 2011

Novel whitening agents were prepared using peptide-Natural origin compound derivatives. The peptide could be an antagonist of MC1R and Natural origin compound were well-known material as a Tyrosinase inhibitor. We also suggest the new assay method which could evaluate the Antagonistic effectiveness to MC1R using cAMP signaling pathway. 24 candidates were synthesized and 11 peptide derivatives were selected by cAMP assay method. To evaluate cAMP assay, the selected peptide derivatives were assayed to evaluate their melanogensis inhibitory activity. At this work, we could know that the sequences which include -RW- have a melanogensis inhibitory activity, and cAMP assy could use as a evaluating method of MC1R antagonist. But, to evaluate the whitening activity of some material, cross-checking with melanin inhibitory assay method was recommended.

• Microbiology and Biotechnology Letters
• /
• v.19 no.3
• /
• pp.235-241
• /
• 1991

- A phthalic acid derivative and basic macrolide antibiotics, with antimicrobial activity against Gram positive bacteria and phytopathogenic fungi, respectively, were found to be produced by a strain 88-GT-161 identified as being a variety of Streptomyces melanosporofaciens. This paper describes an isolation procedure of the active compounds produced by this strain, their in vitro and in vivo (pot test) antimicrobial activites, and structure determination of one of the compounds, bis (2-ethylhexyl) phthalate, a phthalic acid derivative antibiotic. This compounds, upon cornparision with authentic bis (2-ethylhexyl) phthalate, dioctyl phthalate, revealed a difference in antimicrobial activity even though physico-chemical properties of these two compounds seemed indentical. This is the first report that dioctyl phthalate is biosynthetically produced by a Streptomyces sp. and shows antimicrobial activity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.48-48
• /
• 2009

최근 빠른 동작속도와 고 집적도를 얻기 위해 metal oxide semiconductor field effect transistor (MOSFET) 의 크기는 계속 해서 줄어들고 있다. 동시에 게이트의 절연층도 얇아지게 된다. 절연층으로 사용되는 $SiO_2$ 의 두께가 2nm 이하로 얇아 지게 되면 터널링에 의해 누설 전류가 발생하게 된다. 이 문제를 해결하기 위해 $SiO_2$ 를 대체할 고유전체 물질의 연구가 활발하다. 고유전체 물질 중에는 $ZrO_2,\;Al_2O_3,\;HfO_2$ 등이 많이 연구 되어 왔다. 하지만 유전상수 이외에 band gap energy, thermodynamic stability, recrystallization temperature 등의 특성이 좋지 않아 대체 물질로 문제점이 있다. 이를 보안하기 위해 산화물을 합금과 결합시키면 서로의 장점들이 합쳐져 기준들을 만족하는 물질을 만들 수 있고 $HfAlO_3$가 그 중 하나이다. Al를 첨가하는 이유는 문턱전압을 낮추기 위해서다. $HfAlO_3$는 유전상수 18.2, band gap energy 6.5 eV, recrystallization temperature 800 $^{\circ}C$이고 열역학적 특성이 안정적이다. 게이트 절연층은 전극과 기판사이에 적층구조를 이루고 있어 이방성인 드라이 에칭이 필요하고 공정 중 마스크물질과의 선택비가 높아야한다. 본 연구는 $HfAlO_3$박막을 $BCl_3/Ar,\;N_2/BCl_3/Ar$ 유도결합 플라즈마를 이용해 식각했다. 베이스 조건은 RF Power 500 W, DC-bias -100 V, 공정압력 15 mTorr, 기판온도 40 $^{\circ}C$ 이다. 가스비율, RF Power, DC-bias, 공정 압력에 의한 마스크물질과 의 선택비를 알아보았다.

• The Korean Journal of Pesticide Science
• /
• v.2 no.1
• /
• pp.24-31
• /
• 1998

Chemical derivative synthesis of ricinine, an active compound of Ricinus communis which showed high mortality against brown planthopper (Nilaparvata lugens), was performed to improve its pesticidal activity and the toxicity of 12 synthetic derivatives against major insect pests and phytopathogenic fungi were examined. Carbamate derivatives of ricinine could be synthesized from the precursor of ricinine, chloronorricinine and norricinine, whereas the derivatives were not synthesized from chlororicinic acid and ricinic acid having ketone group of pyridine ring. In organophosphates, reaction with oxon type of phosphate gave better yield than thiono type. Among the organophosphate derivatives of ricinine, thiono type of derivative structure gave $96.3%{\sim}100%$ mortality of the brown planthopper and the two-spotted spider mite (Tetranychus urticae) at 500 ${\mu}g/ml$ level. On the other hand, carbamate derivatives did not show insecticidal activity. In the fungicidal activity of ricinine derivatives, the derivative having amino radical at the 2 position of ricinine gave 85 to 100% of mycelium growth inhibition effect against ten major plant pathogens at the 200 ${\mu}g/ml$ level. In particular, the control value of the derivative on the rice blast (Pyricularia grisea) and barley powdery mildew (Erysiphe graminis) at the 250 ${\mu}g/ml$ level in vivo under greenhouse conditions was 92% and 96%, respectively.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.36 no.3
• /
• pp.233-240
• /
• 2010

Derivatives of a novel natural compunds, melanostatin (PLG-$NH_2$) were prepared by solid phase synthesis[1,2] and assayed to evaluate their melanogensis inhibitory activity. Also, a small library (natural compound-XLG-$NH_2$, natural compound-X LG-OH) was prepared with same method for increasing synthetic yield and cost-reduction. PLG-$NH_2$ (Proline-Leucine-Glycine-$NH_2$) was well-known tripeptide as its $\alpha$-MSH release-inhibiting activity and tyrosinase inhibitory activity[3-5]. In order to choose best candidate for peptide derivatization, various natural compounds were screened by their tyrosinase inhibitory activity. As a result, caffeic acid and coumaric acid were selected. Most of these derivatives showed better activities than the parent natural compound, melanostatin.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1996.04a
• /
• pp.163-163
• /
• 1996

Peptide 유도체, 특히 tyrosine을 함유한 peptide 유도체는 항암제 개발을 위한 연구의 관심이 되고 있다. Thiophosphotyrosine을 함유한 peptide는, 종양 발현에 관련되는 여러 효소의 억제제로써, 즉 protein tyrosine kinase(PTK)의 억제제 및 protein tyrosine phosphatase(PTPase)의 억제제 혹은 cytosolic protein의 결합을 방지하는 차단제로 사용할 수 있으며 궁극적으로 항암제 개발에 응용할 수 있다. 이에, t-BOC chemistry를 이용하여 t-BOC-tyrosine을 출발물질로 하고, cyanoethyl 기를 phosphate protecting group으로 사용하여 thiophosphotyrosine을 함유한 peptide 유도체의 합성에 필요한 중요한 중간체 인 N-(tert-butoxycarbonyl)-O-(dicyanoethylthio-phosphene)-L-tyrosine을 합성하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.3
• /
• pp.406-409
• /
• 2012

The classical electromagnetically-induced transparency(EIT)-like switching in metamaterial was experimentally and theoretically demonstrated in the microwave-frequency region. The metamaterial unit cell consists of two identical split-ring resonators, which are arranged on both sides of a dielectric substrate with asymmetry. It is found that the classical EIT-like switching can be achieved by changing the polarization of the incident electromagnetic wave. The results of this study are promising for practical applications.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.6
• /
• pp.946-950
• /
• 2004

Young radishes which were grown in the soil containing sulfur increased quinine reductase (QR) activity in Hepa 1clc cells and isothiocyanate-like compound analyzed by HPLC. QR inducing activity was maximum in young radishes grown with 1,818 g/㎥ sulfur and was decreased when the soil was neutralized with lime mortar in order to improve a recovery. These results have suggested that consumption of young radishes, especially grown in the presence of sulfur, would prevent from cancer incidence through inducing detoxification enzymes and could have therapeutic effects for chemoprevention.

• The Korean Journal of Mycology
• /
• v.17 no.2
• /
• pp.57-65
• /
• 1989

The effect of various cellulosic and hemicellulosic substrates on the induction of cellulase and xylanase complexes in Aapergillus nidulans was investigated. The most efficient substrates for the induction of cellulase and xylanase complexes were carboxymethylcellulose for endoglucanase, cellobiose for ${\beta}-glucosidase$, and xylan for endoxylanase and ${\beta}-xylosidase$, respectively. However, the mixtures of these substrates, especially CMC-xylan and CMC-xylan-laminarin mixture, were much more effective not only for the enhancement of the biosynthesis of all the cellulase and xylanase complexes but also for the balanced production of these enzyme components than individual substrate. The polyacrylamide gel electrophoresis followed by activity staining showed the variation in the patterns and relative intensity of ${\beta}-glucosidase$, endoglucanase and endoxylanase components in individual enzyme preparations from A. nidulans cultures grown on different substrates. These results suggest that the biosynthesis is of cellulase and xylanase systems in A. nidulans is regulated in coordination at the level of induction.

• Korean journal of applied entomology
• /
• v.50 no.2
• /
• pp.107-113
• /
• 2011

Benzylideneacetone (BZA) is a compound derived from culture broth of an entomopathogenic bacterium, Xenorhabdus nematophila (Xn). Its immunosuppressive activity is caused by its inhibitory activity against eicosanoid biosynthesis. This BZA is being developed as an additive to enhance control efficacy of other commercial microbial insecticides. This study was focused on the enhancement of the immunosuppressive activity of BZA by generating its chemical derivatives toward decrease of its hydrophobicity. Two hydroxylated BZA and one sugar-conjugated BZA were chemically synthesized. All derivatives had the inhibitory activities of BZA against phospholipase $A_2$ ($PLA_2$) and phenoloxidase (PO) of the diamondback moth, Plutella xylostella, but BZA was the most potent. Mixtures of any BZA derivative with Bacillus thuringiensis (Bt) significantly increased pathogenicity of Bt. BZA also inhibited colony growth of four plant pathogenic fungi. However, BZA derivatives (especially the sugar-conjugated BZA) lost the antifungal activity. These results indicated that BZA and its derivatives inhibited catalytic activities of two immune-associated enzymes ($PLA_2$ and PO) of P. xylostella and enhanced Bt pathogenicity. We suggest its use to control plant pathogenic fungi.