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        검색결과 466

        206.
        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
        207.
        2008.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have fabricated and evaluated newNew high high-efficiency green green-light light-emitting phosphorescent devices with an emission layer of [TCTA/TCTA1/3TAZ2/3/TAZ] : Ir(ppy)3 were fabricated and evaluated, and compared the electroluminescence characteristics of these devices were compared with the conventional phosphorescent devices with emission layers of (TCTA1/3TAZ2/3) : Ir(ppy)3 and (TCTA/TAZ) : Ir(ppy)3. The current density, luminance, and current efficiency of the a device with an emission layer of (80Å-TCTA/90˚Å-TCTA1/3TAZ2/3/130Å-TAZ) : 10%-Ir(ppy)3 were 95 mA/cm2, 25000 cd/m2, and 27 cd/A at an applied voltage of 10 V, respectively. The maximum current efficiency was 52 cd/A under the a luminance value of 400 cd/m2. The peak wavelength and FWHM (FWHM (full width at half maximum) in the electroluminescence spectral were 513 nm and 65 nm, respectively. The color coordinate was (0.30, 0.62) on the CIE (Commission Internationale de I'Eclairage) chart. Under the a luminance of 15000 cd/m2, the current efficiency of the a device with an emission layer of (80Å-TCTA/90Å-TCTA1/3TAZ2/3/130Å-TAZ) : 10%-Ir(ppy)3 was 34 cd/A, which has beenshowed an improvement of improved 1.7 and 1.4 times compared to those of the devices with emission layers of (300Å-TCTA1/3TAZ2/3) : 10%-Ir(ppy)3 and (100Å-TCTA/200Å-TAZ) : 10%-Ir(ppy)3, respectively.
        4,000원
        210.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        조직공학용 생체 물질로 사용하고자 가교제 1,3-butadiene diepoxide (BD)를 사용하여 락타이드와 가교시킨 히아루론산 막을 제조하였다. 막의 락타이드 및 BD 반응도는 핵자기 공명 분광볍으로 결정하였다. BD 농도가 높을 경우 6%이하의 성장저해 현상이 나타났으나 그 값은 세포 성장에 문제되지 않을 정도로 충분히 낮았다. 가교온도가 낮을수록 탄성 율은 증가하고 팽윤도는 감소하였다. 막의 생분해속도는 가교온도가 낮을수록 감소하였다. 약물방출 실험 결과 가교 온도가 낮을수록 막을 통한 약물 투과는 감소하였다.
        4,000원
        212.
        2008.05 구독 인증기관·개인회원 무료
        A strain of Bacillus thuringiensis, named Bt 1-3, was isolated from Korean soil sample and it showed high insecticidal activity against Plutella xylostella. Bt 1-3 was deterimined to belong to ssp. aizawai (H7) by an H antiserum agglutination test and produced bipyramidal-shaped crystal proteins. PCR analysis with specific cry gene primers showed that Bt 1-3 contained cry1Aa, cry1Ab, cry1C, cry1D and cry2Ab genes. In addition, this isolate showed high uptake rate of foreign plasmid by electroporation. Based on these characteristics of Bt 1-3, we tried to construct a spore-free Bt 1-3 mutant by knock-out sigG gene, which is known as a key transcription factor during sporulation. First, we constructed a basal vector, named pDST, consisting of erythromycin resistant gene (EmR), partial polyhedrin gene and temperature sensitive origin of replication gene (Orits). Subsequently, according to the chromosomal DNA sequence of Bt subsp. konkukian 97-27, we amplifed upstream and downstream regions of Bt 1-3 sigG, and cloned into pDST (pDST-G). So far, several EmR colonies were obtained by electroporating into the wildtype Bt 1-3 and crossover by homologous recombination is going on.
        214.
        2008.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In general, anionic and cationic surfactants are incompatible because their mixtures form insoluble complexes. There are, however, some complexes that are soluble and behave like regular surfactants, specifically like nonionic surfactants, thus named pseudo-nonionic surfactant complexes. Pseudo-nonionic complexes are more effective and efficient than their ionic surfactant components as shown by their equilibrium and dynamic surface tensions and interfacial tensions. They pack at the interface more than their ionic components. Since, pseudo-nonionic complexes show their own characteristics, they can be treated as separate classes of surfactants distinct from ionic and nonionic surfactants. Novel cationic surfactant was synthesized, having the polyhydroxyl group at the head group. We found that aqueous mixtures of our cationic surfactant and usual anionic surfactant(SDS) could form homogeneous solutions even at high concentration. The properties of mixed surfactant solutions were measured. Foam stability, CMC(critical micelle concentration), water hardness tolerance and thickening effect were tested. The foam stability of mixed surfactants was very good and various synergy effects were observed.
        4,000원
        215.
        2008.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Three species: Anorthoa angustipennis (Matsumura), Harutaeographa stenoptera (Staudinger), and Cerastis pallescens (Butler), are recorded for the first time from China, and Nikara castanea (Moore) is newly added to the fauna of Northeast China. The image of adult, genitalic characteristics, and the distributions are given as necessary.
        3,000원
        219.
        2007.10 KCI 등재 구독 인증기관·개인회원 무료
        1,1- Bis(3’-indolyl)-l-(p-methoxyphenyl)methane (DIM- C- pPhOCH.3) is a methylenc - substituted diindolylmethanes (C-DIM) ana log that acti vates the orphan receptOl‘ nerve growth factor-induced-B (NGFI-B, Nur77) , RNA inteference studies with small inhibitory RNA for Nur77 demonstrate that DIM-C-pPhOCH:J induces Nur77-dependent and - independent apoptosis, and this study has focused on delineating the Nur77-independent proapoptotic pathways induced by the C-DIM analog DIM-C-pPhOCH3 induced caspase-dependent apoptosis in RKO colon cancer cells through decreased mitochondrial membrane potential which is accompanied by increased mitochondrial bax/bcl-2 ratios and release of cytochrome c into the cytosol DlM-C一pPhOCH.3 also induced phosphatidylinositol-3-kinase-dependent activation of early growth response gene-l whi ch, in turn, induced expression of the proapoptotic nonsteroidal anti-inflammatory drug- activated gene-l (NAG- l) in colon tumors in athyrnic nude mice bearing RKO cells as xenografts, DIM-C-pPhOCH.3 also activated the extrinsic apoptosis pathway through increased phosphorylation of c- jun N-terminal kinase which, in turn, activated C/EBP homologous transcription factor (CHOP) and death receptor 5 (DR5) , Thus, the effectiveness of DIM-C-pPhOCH.3 as a tumor growth inhibitor is through activation of Nur77-dependent and -independent pathways
        220.
        2007.10 KCI 등재 구독 인증기관·개인회원 무료
        Heme oxygenase-l (HO-l) exhibits cyt oprotective effects in many different cell types and is induced by nicotine exposure in human gingival fibroblasts‘ However‘ therole of HO- l in cancer cells exposed to nicotine has not previously been descnbed We investigated the effects of nicotine on HO-l protein expression and cell viability in immortalized (IHOK) and malignant (HN12) human ora l keratinocyte cells using the MTT assay and Western blotting. We al so examined the involvement of t he phosphoinosit ide-3-0H- kinase (PI3K), mitogen-acti vated protein kinase (MAPK) , and nucJear factor-κ B (NF-κ B) signaling pathways in nicotine-induced cytotoxicity and HO- l levels in IHOK and HN12 cell s‘ Nicotine induced HO- l pro ducti on and had cytotoxic effects on cells in both a concentration- and time-dependent manner. Nicotine-induced cytotox icity and accumulation of HO- l were greater in JJ-IOK cells than in HN12 cells Molecular inhibitors of the ERK, p38 MAP kinase, PI3K, and NF-κ B signaling pathways blocked the cytotoxic effects and induction of J-IO-l expression by nicotine. Treatmen t with an t ioxida nts (bil irubin, N-acetyl cysteine) protected cells against nicotine-induced cytotoxicity and blocked the upregula tion of J-IO- l, the effects of which were more pronounced in II-IOK cells than in HN12 cells Collecti vely, these results suggest that J-IO- l plays a principal role in the protective response to nicotine in oral cancel and immortalized keratinocytes. Moreover, the addition of exogenous antioxidants may help to protect oral epithelial cells as chemopreventive agents against nicotine-induced oxidative stress.