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        검색결과 196

        41.
        2012.06 구독 인증기관 무료, 개인회원 유료
        This case study investigates the KIKO currency option that has been a social issue in recent years among developing countries, especially Korea, where the financial derivatives market is in a state of rapid growth. The forward transaction which becomes a basis of derivatives is intended to hedge risks that may be caused by a future change in asset prices. Although it originates from a simple form of agricultural transactions, there currently exists a variety of derivatives in more sophisticated forms. In the Korean agricultural industry, the need to use such derivatives is great, as there is a huge risk of price fluctuation in agricultural products due to frequent adverse weather. In addition, many developing countries with export-led industrial structures similar to Korea’s, of necessity must resort to currency hedging as a method of reducing relevant risk. However, in most cases, the lack of understanding about financial derivatives results in an inappropriate application of these derivatives. The KIKO in this study represents such cases. Since 2007, KIKO has been sold in Korea to many small- and medium-sized export companies for the purpose of currency hedging when the exchange rate between the Korean won and the U.S. dollar was in a downward spiral. The main focus of this study is a case which is most representative of KIKO. As inflation rapidly increased during the financial crisis in the U.S. at the end of 2007, derivatives became a hot issue in the courts rather than in the financial markets. This case study investigates what KIKO and the fierce legal debates over it imply, from the perspective of the option of value evaluation in order to suggest not only a direction in which companies can utilize financial derivatives, but also a roadmap for the future derivatives market.
        4,000원
        42.
        2012.05 구독 인증기관·개인회원 무료
        The object of this study was the acaricidal activities of acetophenone (AP) and its derivatives for their potentials as natural acaricides using fumigant and contact toxicity bioassays against Dermatophagoides farinae, D. pteronyssinus, and Tyrophagus putrescentiae. Based on the LD50 values of AP derivatives against D. farinae, 3’-methoxyAP (0.41 ㎍/㎠) was 89.9 times more toxic than DEET (36.87 ㎍/㎠), followed by 4’-methoxyAP (0.52 ㎍/㎠), 2’-methoxyAP (0.75 ㎍/㎠), 2’-hydroxy-5’-methoxyAP (1.03 ㎍/㎠), 2’-hydroxy -4’-methoxyAP (1.29 ㎍/㎠), AP (1.48 ㎍/㎠), 2’-hydroxyAP (1.74 ㎍/㎠), 2’,5’-dimethoxyAP (1.87 ㎍/㎠), 2’,4’-dimethoxyAP (2.10 ㎍/㎠), and benzyl benzoate (9.92 ㎍/㎠). With regard to structure-activity relationships between acaricidal activity and functional groups (hydroxyl and methoxy groups) on the AP skeleton, a mono-methoxy group (2’-, 3’-, and 4’-methoxyAP) on the AP skeleton was more toxic than the other groups (2’,4’- and 2’,5’-dimethoxyAP, 2’- and 4’-hydroxyAP, 2’-hydroxy-4’-methoxyAP, 2’-hydroxy-5’-methoxyAP, and 4’-hydroxy-3’-methoxyAP). These results indicated that acaricidal activity against three mite species was changed with the introduction of functional radicals (hydroxyl and methoxy groups) onto the AP skeleton.
        43.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chitosan is widely used in cosmetics and medical fields. Special emphasis has been put on the chemical modification of chitosan to explore its full potential. We have described the synthesis and biological activity of novel peptide amino acid derivatives. The polyamino acid derivatives were synthesized by introducing alkylamine functional group on chitosan at C-6. The poor aqueous solubility of chitosan derivatives hinder both pharmacological studies and pharmaceutical development. To make amino acid coupled chitosan derivatives with improved biological effect and solubility, some attempts have been taken to consist of amino peptide group like aspartic acid and phenylalanine-aspartic acid derivatives onto chitosan C-6. The resultingly substituted chitosan was characterized by solubility in various solvents. We measured chitosan derivatives with 1H-NMR and 13C-NMR. Also, We were investigated on the physical properties and biological activities of these products.
        4,200원
        44.
        2011.10 구독 인증기관·개인회원 무료
        5-Hydroxy-1,4-naphthoquinone and its derivatives were evaluated for insecticidal effect against Sitophilus oryzae and S. zaemais adults. This study was examined using fumigant method. Mortality was determined after 72 h of treatment. 5-Hydroxy-1,4-naphthoquinone showed strong (+++) activity at 5 mg and the 1,4-naphthoquinone showed strong (+++) and moderate (++) activity at 5 mg, against S. oryzae and S. zaemais, respectively. However, 5-hydroxy-2-methyl-1,4-naphthoquinone, 2-methyl-1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, and 2-methoxy-1,4-naphthoquinone had non-activity (-) at 5 mg. Based on the LD50 values, the compound most highly effect to S. oryzae was 1,4-naphthoquinone (0.012 mg/cm2), followed by 5-hydroxy-1,4-naphthoquinone (0.013 mg/cm2). However, against S. zeamais, 5-hydroxy-1,4-naphthoquinone (0.044 mg/cm2) was the most toxic compound, followed by 1,4-naphthoquinone (0.155 mg/cm2). These results suggest that the introduction of various functional group (hydroxy, methyl and methoxy) into the 1,4-naphthoquinone skeleton contributes to insecticidal activity. Accordingly, 5-hydroxy-1,4-naphthoquinone and 1,4-naphthoquinone could be used highly effective rice weevil control agents.
        46.
        2011.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        산화방지제인 아스코르빈산(AA), 에리쏘르빈산(isoAA), 아스코르빌파르미테이트(AP), 아스코르빌스테아레이트(AS)에 대한 ‘식품 중 식품첨가물 분석법’을 검증하고 미비점을 개선하였다. 고속액체크로마토그래피 자외선검출기법을 이용하여 검출한계(LOD), 정량한계(LOQ), 상관계수(R2) 등을 측정하였고 돼지기름(lard), 사이다를 이용한 모델식품에서의 회수율과 재현성을 측정하였다. AA와 isoAA의 검출한계는 각각 0.46, 0.48 μg/mL이었으며, 회수율은 각각 86.35-94.78, 84.76-95.02%를 나타내었고 상관계수는 모두 0.999이상을 보였다. AP와 AS의 현 분석법은 메탄올을 용매로 사용하지만 메탄올 용매에서 AP와 AS는 불안정하였다. 냉장온도에서 에탄올을 용매로 사용 시 다른 용매에 비해 유의적으로 높은 안정성을 나타내어 기존 용매의 불안정성을 개선할 수 있었다.
        4,000원
        47.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Melanoma is the most aggressive form of skin cancer and is the fastest growing type of cancer in the United States. We report here the synthesis of a novel series of quinazolinylmethoxybenzene derivatives 1a-c and their antiproliferative activities against A375 human melanoma cell line. Among them, urea compound 1a (IC50 = 4.8 μM) having 4-chloro-3-trifluoromethylphenyl moiety showed superior antiproliferative activity to Sorafenib (IC50 = 5.5 μM) as a reference compound. These results will helpful for designing structure of a therapeutic agent for the treatment of melanoma.
        4,000원
        48.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Melanoma is the most serious type of skin cancer as a malignant tumor of melanocytes. In this work, the syntheses of a novel series of benzaminoquinoline derivatives 1a-c and their antiproliferative activities against A375 human melanoma cell line were described. All the compounds (IC50=0.78-1.02μM) showed superior antiproliferative activities to Sorafenib (IC50=5.58μM) as a reference compound. These results suggested that benzaminoquinoline derivatives have potentials as a therapeutic agent for the treatment for melanoma.
        4,000원
        49.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Conventional additives were added to a newly synthesized base oil to create synthetic lubricants. Commercial polyol ester prepared in this laboratory were obtained as esterification of 1,1,1-trimethylol propane and respectively. This newly synthesized base oil had a variable chemical structure that could achieved the following properties; oxidation or thermal stability, low temperature fluidity, and higher flash points. When compared with commercial mineral lubricants, the synthetic lubricants show superior thermal and oxidation stability, and anti-wear properties.
        4,200원
        50.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, a novel series of aminoisoquinolinylamide derivatives 1a-c and 2a-f were synthesized via several reaction steps, starting from 2-methyl-4-nitrobenzonitrile (3) and 1-chloro-5-nitroquinoline (8). And their antiproliferative activities were screened against A375 human melanoma cell line compared to Sorafenib as a reference compound. Among them, compound 1b and 1c exhibited meaningful inhibitory activities. These results demonstrated that aminoisoquinolinylamide scaffold possesses the possibility as the treatment for melanoma.
        4,000원
        51.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The benzophenone derivatives(4-CH3O-4'-NO2 and 3,4'-di-NO2) are synthesized by the Fridel-Craft acylation and the nitration method. Electrochemical redox potentials of the benzophenone derivatives (4-CH3O, H, 3-Cl, 3-NO2, 4-NO2, 4-CH3O-4'-NO2, 3,4'-di-NO2) are measured by using cyclic voltammometry. In the relationship of summing Hammett value and redox potential, we find a proportional constant(σ) that shows a good relation with an electrochemical property and a reactivity of the benzophenone derivatives. The benzophenone substituted with the electron donating groups(4-OCH3 and 4-OCH3-4'-NO2) are higher the energy in the LUMO level, then increasing a band-gap energy(Eg), their Egs are obtained as a 3.94 eV and 3.59 eV, respectively.
        4,200원
        52.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, the synthetic approaches for a series of aminopyrimiclinylmethanone derivatives 1a-i, which versatile biological activities such as antibacterial and anticancer activities are expected from a structural point of view, were described. Nicotinic acid was converted to (2-methylsulfonylpyrimidin-4-yl) (pyridin-3-yl)methanone, a key intermediate, which was reacted with nucleophiles to yield the desired aminopyrimidinylmethanone derivatives 1a-i bearing various substituents.
        4,000원
        53.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is focused on the synthesis of urea and amide derivatives particularly, since the amide moiety is an essential binding group at the binding site. Urea derivatives 3-7 and 13-14 were obtained by reaction of 2-aminopyrimidines and other amines with diverse isocyanates in pyridine as a solvent under reflux. The urea derivatives were obtained in low yield because of the highly electron deficient nature of the amino group of the 2-aminopyrimidine. Amide derivatives 8-10 were obtained in moderate yields by reaction of compound 1 with aryl chloride derivatives. Also, arylamine 11 was synthesized by Buchwald-Hartwig amination in moderate yields. Most of the compound did not show good activity against A375P melanoma cells, compared with Sorafenib as control compound.
        4,000원
        54.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A group of new N,N-bis(5-acetylpyridin-2-yl)phenylamine derivatives was synthesized in good yield applying an optimized Buchwald-Hartwig amination protocol. The synthesized compounds showed UV absorption maxima in the range of 320-360 nm, and showed good luminescence at dilute concentrations in the blue region of the spectra (in the range of 480-497 nm). They showed also a bathochromic shift associating the increase in solvent polarity. The synthesized compounds could be investigated for use in OLEDs or as potential monomers for PLEDs.
        4,000원
        55.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Akt, a serine/threonine protein kinase as a viral oncogene, is a critical regulator of PI3K-mediated cell proliferation and survival. On translocation, Akt is phosphorylated and activated, ultimately resulting in stimulation of cell growth and survival. As a part of our program toward the novel Akt1 inhibitors with potent activity over PI3K signaling pathway, we found primary hit compound 2 with an IC50 value of 620μM from protein kinase focused library. Based on the structural features of 2, new 1,3,4-thiadiazole derivatives were designed by the introduction of aromatic and heteroaromatic moieties onto thiadiazole nucleus. In this work, a series of 1,3,4-thiadiazole derivatives 1a-1 were synthesized and evaluated for Akt1 inhibitory activity.
        4,000원
        56.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although the pyrimidine derivatives were obtained in low yields ranging from 8% to 20%, we reported the successful preparation of N,N-diaryl-pyrimidin-2-amine derivatives starting from the corresponding 2-aminopyrimidines (1a-1c), by direct palladium-catalyzed arylation using different arylbromides. The reasons of low yields are thought to be the electronic and steric effects by the neighboring aromatic systems. The absorption spectra and photoluminescent spectra of compounds (3a 3g and 4a-4c) were measured using dichloromethane on the concentration of 25 mM by UV vis spectroscopy and luminescent spectroscopy. Pyrimidine derivatives 4a, 4b, and 4c showed moderate emission maxima at 474 nm, 481 nm, and 367 nm, respectively, while other compounds showed very weak photoluminescence or no photoluminescence at all.
        4,000원
        57.
        2008.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 다중 균열 구조물에서의 균열 진전에 따른 에너지 해방을 및 고차 미분값을 구할 수 있는 가상균열 진전법을 제시한다. 이 방법은 다중 균열 체계의 에너지 해방율과 고차 미분값이 단 한번의 해석으로 수행될 수 있는 장점이 있다. 예제에서 얻어진 해의 최대 오차는 에너지 해방율 0.2%, 일차 미분값이차 미분값 이다 이 방법으로 구한 에너지 해방률의 미분값들은 파괴 확률을 구하거나, sire effect law에 적용될 수 있다.
        4,000원
        58.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The central role of tyrosine phosphorylation in cell proliferative signaling mechanisms provides another target for chemotherapy. The aim of this research is to develop new quinazoline derivatives that possess the inhibitory activity for depidermal growth factor receptor (EGFR) tyrosine kinase (TK) as protein kinase inhibitors. In this work, a series of new 4-anilino-6-guanidino-7-methoxyquinazoline derivatives (12a-l) were synthesized by the introduction of guanidine moiety at C-6 of quinazoline nucleus and evaluated for their EGFR TK inhibitory activities.
        4,300원
        59.
        2008.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        미강 추출 상업용 유통 감마오리자놀의 콜레스테롤 자동산화에 의한 C-7 산화 콜레스테롤 유도체 생성 저해 효과가 수용성 모델 시스템을 이용하여 검토되었다. C-7 콜레스테롤 산화 유도체 (C-7 oxidized cholesterol derivatives: C-7 OCDs) 생성을 위해 콜레스테롤과 감마오리자놀이 분산된 수용성 모델시스템은 구리이온을 촉매로 pH 5.5와 80ºC의 가혹 조건에서 20시간 동안 반응되었다. 산화 유도 기간에 따른 C-7콜레스테롤 산화 유도체 (7-ketocholesterol, 7α-hydroxy-cholesterol 과 7b-hydroxycholesterol)의 생성 정도와 감마오리자놀 및 콜레스테롤 변화 추이 정도가 핵산과 에틸아세테이트를 이용한 용매 추출법과 고속액체크로마토그래프 (high-performance liquid chromatography) 테크닉을 이용 정량적으로 분석되었다. 분석 결과 콜레스테롤 산화 유도 기간에 따른7-ketocholesterol 생성비율은 7-hydroxycholesterol 이성체 (α-형:β-형) 대비 약 2:1의 비율로 생성되었으며, 7-hydroxycholesterol 이성체에 있어서는 α-형 대비 β-형의 생성 정도가 약 1:2의 비율로 나타났고, 총 C-7 산화콜레스테롤의 생성은 상대적인 고농도(300 ppm) 감마오리자놀 처리 모델 시스템에서 효과적으로 저해되었다.
        4,000원
        60.
        2008.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Beauvericin과 enniatin H, I, 그리고 MK1688의 생산에 미치는 온도와 수분함량의 효과를 조사하였다. 쌀을 기질로 할 경우 25℃, 40% 수분함량에서 조사된 모든 독소들이 최대로 생산되었으며, 15℃의 온도에서 접종 2주 후 50 μg/g이하의 생성량을 나타내었다. 수분함량 10%에서도 접종 후 6주차에 모든 독소들의 검출이 확인되었으며, 이는 이 독소들이 0.75정도의 낮은 수분활성도에서도 생성될 수 있음을 나타낸다. 한편, 국내에서 생산된 곡류들(65종)에 대하여 Fusarium 독소인 beauvericin의 오염을 분석하였다. 국내에서 수확된 65종의 곡류시료 중 6종의 시료에서 beauvericin오염이 확인되었다. 쌀과 현미에서는 beauvericin이 검출되지 않았으며, 2004년산 옥수수 3종, 2004년과 2005산 보리 시료 각 1종, 그리고 2005년 재배된 밀 1종에서 beauvericin이 검출되었다. 가장 높은 오염도를 보인 것은 옥수수 시료이며, 이 시료에서 0.23 μg/g의 beauvericin이 검출되었다. 국내에서는 beauvericin에 대한 곡류 오염 조사가 이 연구에서 처음으로 이루어졌으며, 국내산 곡류에서도 beauvercin이 검출됨에 따라 지속적으로 오염도를 조사할 필요가 있다.
        4,000원
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