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        검색결과 127

        41.
        2016.04 구독 인증기관·개인회원 무료
        Ionizing irradiation can be used as an alternative to chemical fumigants for disinfestation of cut flowers, agricultural products, seeds, foods, medical products, and spices. In this study, we investigated the effect of electron beam irradiation on reproduction and development in Spodoptera litura. When irradiated to the adults, there was no difference in fecundity. However, egg hatching was considerably decreased. When irradiated to the pupae, fecundity was decreased as dose increased and wing deformity of newly emerged adults was increased as time passed. When irradiated to the larvae, developmental period and pupa deformity was significantly increased. In order to investigate the molecular mechanism of sterility and abnormal development, we performed quantitative real-time PCR and SDS-PAGE.
        42.
        2015.12 구독 인증기관 무료, 개인회원 유료
        MicroRNA (miRNA, miR) is essential in regulating cell differentiation either by inhibiting mRNA translation or by inducing its degradation. However, the role of miRNA in odontoblastic cell differentiation is still unclear. In this study, we examined the molecular mechanism of miR-27-mediated regulation of odontoblast differentiation in MDPC-23 mouse odontoblastic cells derived from mouse dental papilla cells. The results of the present study demonstrated that the miR-27 expression increases significantly during MDPC-23 odontoblastic cell differentiation. Furthermore, miR-27 up-regulation promotes the differentiation of MDPC-23 cells and accelerates mineralization without cell proliferation. The over-expression of miR-27 significantly increased the expression levels of Wnt1 mRNA and protein. In addition, the results of target gene prediction revealed that Wnt1 mRNA has an miR-27 binding site in its 3’UTR, and is increased by miR-27. These results suggested that miR-27 promotes MDPC-23 odontoblastic cell differentiation by targeting Wnt1 signaling. Therefore, miR-27 is a critical odontoblastic differentiation molecular target for the development of miRNA based therapeutic agents in dental medicine.
        4,000원
        44.
        2015.06 구독 인증기관 무료, 개인회원 유료
        Curcumin (diferuloylmethane), a constituent of turmeric powder derived from the rhizome of Curcuma longa, has been shown to inhibit the growth of various types of cancer cells by regulating cell proliferation and apoptosis. However, a need exists to design more effective analogs because of curcumin's poor intestinal absorption. EF-24 (diphenyl difluoroketone), the monoketone analog of curcumin, has shown good efficacy in anticancer screens. However, the effects of curcumin and EF-24 on salivary gland epidermoid carcinoma cells are not clearly established. The main goal of this study was to investigate the effects of curcumin and EF-24 on cell growth and induction of apoptosis in human salivary gland epidermoid carcinoma cells. Our studies showed that curcumin and EF-24 inhibited the growth of HTB-41 cells in a dose- and time-dependent manner, and the potency of EF-24 was > 34-fold that of curcumin. Treatment with curcumin or EF-24 resulted in nuclear condensation and fragmentation in HTB-41 cells, whereas the control HTB-41 cell nuclei retained their normal regular and oval shape. Curcumin and EF-24 promoted proteolytic cleavages of procaspase-3/-7/-9, resulting in an increase in the amount of cleaved caspase-3/-7/-9 in the HTB-41 cells. Caspase-3 and -7 activities were detected in viable HTB-41 cells treated with curcumin or EF-24. These results suggest that the curcumin and EF-24 inhibit cell proliferation and induce apoptosis in HTB-41 human salivary gland epidermoid carcinoma cells, and that they may have potential properties as an anti-cancer drug therapy.
        4,000원
        45.
        2014.10 구독 인증기관·개인회원 무료
        The insecticidal activities of materialsderived from Dryopteris crassirhizoma Nakai against third instar larvae of three species mosquitoes (Culex pipiens, Aedes albopictus and Anopheles sinnensis) were evaluated using a direct contact mortality bioassay. The methanol extracts of D. crassirhizoma showed 100%, 87.8% and 100% larvicidal activity at 1,000 ppm against Cx. pipiens, Ae. albopictus and An. sinensis, respectively. Hexane fraction showed 100% larvicidal activity three species mosquitoes at 500 ppm after 24 hrs. Purification of the biologically active constituents from the hexane extraction with larvicidal activity was done using silica gel column chromatography. H1 and H3 fractions gave 100% mortality to Cx. pipiens, Ae. albopictus and An. sinensis at 100 ppm. H1 fraction separated with methanol to give a H111 through centrifugation. Fraction of the biologically active constituents from the H3 fraction with larvicidal activity was done using methanol. H31 fraction was determined 100% mortality to Cx. Pipiens, Ae. albopictus and An. sinensis at 50 ppm, respectively. Two fractions were analyzed C14H22O (H111, MW206.0) and C11H14O4 (H31, MW210.08) by GC and GC-MS. D. crassirhizoma derived compounds described herein could be useful for managing filed populations as larvicide of Cx. pipiens, Ae. albopictus and An. sinensis.
        46.
        2014.04 구독 인증기관·개인회원 무료
        The larvicidal and repellent activities of 33 plant extracts against two mosquitoes as Culex pipiens and Aedes albopictus were examined using direct contact application for larva and a patch test for adult. Chrysanthemum zawadskii var. alpinum, Cnidium officinale, Ginkgo biloba, Magnolia kobus, and Magnolia denudate at 1,000 ppm caused 100% mortality to Cx. pipiens larva within 24 hr. Ailanthus altissima, Dryopteris crassirhizoma, Houttuynia cordata, Mentha arvensis, Phyllostachys nigra, and Parthenocissus tricuspidata showed over 90% mortality to Cx. pipiens. C. zawadskii var. alpinum, C. officinale, G. biloba, M. kobus, M. denudate, and P. nigra gave 100% mortality at 1,000 ppm to Ae. albopictus. Acorus gramineus, Campanula takesimana, and D. crassirhizoma, showed 97.8%, 94.5%, and 94.4% mortality to Ae. albopictus at 24 hr, respectively. Five plant extracts (C. zawadskii var. alpinum, C. officinale, G. biloba, M. kobus, and M. denudate) showed 100% mortality both Cx. pipiens and Ae. albopictus. However, A. altissima gave 90% larvicidal activity to Cx. pipiens, whereas 7.8% mortality to Ae. albopictus. Several plant extracts which have highly larvicidal activities, were determined repellency against two mosquitoes species.
        47.
        2014.04 구독 인증기관·개인회원 무료
        The insecticidal activities of materials derived from the rhizomes of turmeric, Curcuma longa L., against third instar larva of Culex pipiens and Aedes albopictus were evaluated using a direct contact mortality bioassay. Curcuma longa L. hexane extraction showed 100% larvicidal activity both two mosquitoes species at 1,000 ppm after treated 24 h. Purification of the biologically active constituents from the hexane extraction with larvicidal activity was done using silica gel column chromatography. H1 fraction gave 100% mortality to C. pipiens and A. albopictus at 100 ppm. H12 fraction was determined 100% and 87.8% larvicidal activity to C. pipiens and A. albopictus at 50 ppm, respectively. H12 fraction was analyzed as the sesquiterpene, ar-turmerone (C15H20O) and turmerone(C15H22O) by GC and GC-MS.
        49.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to analyze the correlation between the stature and the muscle performance ratings and the subjective discomfort rations at performing lower arm's pronation and supination according to change sin the height of working table for more efficient performance at designing a working table and performing a work. For the purpose, this study conducted an experiment targeting 40 people in their 20s, who were classified into 4 groups each group composing 10 people at intervals of 5cm from the standard stature of 166.5cm. The experiment measured the maximum isometric pronation and the supination muscular power, and at measuring the factors, the heights of working tables were set as 800mm, 850mm, and 900mm. From the measurement results, it was found that the stature and the maximum muscular power was correlated. That is, as the experiment groups's average stature is higher, the maximum muscular power was higher. For the correlation between the motion patterns(pronation and supination) and the maximum muscular power, it was seen that the maximum muscular power was higher at performing the pronation than the supination. In the correlation between motion patterns and the subjective discomfort ratings, it was seen that the subjective discomfort rating was higher at performing the supination than the pronation. For the correlation between height adjustment and the subjective discomfort ratings, as the height of working table was lower, the subject discomfort rating was lower. Therefore there was no difference in the maximum muscular power according to the height changes of working table, but it was found that as the working table was higher, the user felt more comfortable.
        4,000원
        50.
        2012.03 구독 인증기관 무료, 개인회원 유료
        Opioid receptors have been pharmacologically classified as µ, δ, κ and ε. We have recently reported that the antinociceptive effect of morphine (a µ-opioid receptor agonist), but not that of β-endorphin (a novel µ/ε-opioid receptor agonist), is attenuated by whole body irradiation (WBI). It is unclear at present whether WBI has differential effects on the antinociceptive effects of µ-, δ-, κ- and ε-opioid receptor agonists. In our current experiments, male ICR mice were exposed to WBI (5Gy) from a 60 Co gamma-source and the antinociceptive effects of opioid receptor agonists were assessed two hours later using the hot water (52℃) tail-immersion test. Morphine and D-Ala2,N-Me-Phe4,Gly-ol-enkephalin (DAMGO), [D-Pen2-D-Pen5]enkephalin (DPDPE), trans-3,4-Dichloro-N-methyl-N-[2-(1-pyrrolidinyl)- cyclohexyl]¬benzeneacetamide (U50,488H), and β-endorphin were tested as agonists for µ, δ, κ, and ε-opioid receptors, respectively. WBI significantly attenuated the antinociceptive effects of morphine and DAMGO, but increased those of β-endorphin. The antinociceptive effects of DPDPE and U50,488H were not affected by WBI. In addition, to more preciously understand the differential effects of WBI on µ- and ε¬opioid receptor agonists, we assessed pretreatment effects of β-funaltrexamine (β-FNA, a µ-opioid receptor antagonist) or β-endorphin1-27 (β-EP1-27, an ε-opioid receptor antagonist), and found that pretreatment with β-FNA significantly attenuated the antinociceptive effects of morphine and β endorphin by WBI. significantly reversed the β-EP1-27 attenuation of morphine by WBI and significantly attenuated the increased effects of β-endorphin by WBI. The results demonstrate differential sensitivities of opioid receptors to WBI, especially for µ- and ε-opioid receptors.
        4,000원
        51.
        2012.03 구독 인증기관 무료, 개인회원 유료
        Cytokines are known to function as regulatory molecules that can be produced by virtually every nucleated cell type in the body, including lymphocytes, monocytes/macrophages, epithelial cells, fibroblasts, and many others. Cytokines include lymphocyte-derived factors (lymphokines), monocyte-derived factors (monokines), hematopoietic factors (colony-stimulating factors), connective tissue/ growth factors, and chemotactic chemokines. Cytokines released in response to infection can affect tumor development in different ways. When exposed to infectious agents, cytokines are secreted by sentinel cells, such as macrophages and dendritic cells. These cytokines include interleukin 1 (IL-1) and tumor necrosis factor-α, as well as others, such as IL-6, IL-12, and IL-18. When released in sufficient quantities, these molecules can cause inflammation. Chronic inflammation is highly associated with tumor initiation, promotion, and progression. In this article, we review the roles and mechanisms of cytokines in tumor development.
        4,300원
        52.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 환경스트레스 저항성이 증진된 페튜니아를 개발하기 위하여 NDPK2유전자 도입 형질전환 계통 NDPK2-7-1와 SOD2 유전자 도입 형질전환 계통 SOD2- 2-1-1-35간의 교잡에 의해 획득된 후대들의 비생물적 스트레스 저항성을 조사하기 위해 수행되었다. 비 생물적 스트레스 유발원인 메틸바이올로젠(methyl viologen, MV) 100 μM과 200 μM 처리에서 교잡후대들은 그들의 교배 모본 SOD2 유전자나 NDPK2 유전자가 단독으로 도 입된 형질전환 계통이나 비형질전환체 보다 메틸바이 올로젠에 의한 피해를 적게 받았다. 이는 SOD2 유전 자나 NDPK2 유전자가 단독으로 도입된 형질전환 계 통간 교잡에 의해 획득된 후대들이 그들의 교배모본 (SOD2 유전자나 NDPK2 유전자가 단독으로 도입된 형질전환 계통)이나 비형질전환체 보다 산화적 스트레 스에 대한 저항성이 증진되었음을 증명해 준다고 할 수 있다. 이들 교잡후대들은 초장 등 11종류의 양적형질의 특성이 비형질전환체에 비해 약간 길거나 짧긴 하였지 만 비형질전환체와 거의 유사하였으며, 꽃 색갈이나 모양 또한 그들의 교배모본 (SOD2 유전자나 NDPK2 유전 자가 단독으로 도입된 형질전환 계통)이나 비형질전환 체와 차이가 없었다.
        4,000원
        53.
        2010.09 구독 인증기관 무료, 개인회원 유료
        The effects of chitosan upon the experimentally induced differentiation of MDPC-23 cells, derived from mouse dental papilla cells, were investigated by RT-PCR, observations of cell morphology and Alizaline red-S staining. Chitosan was found to significantly increase and accelerate the expression of ALP mRNA but decrease the ColI transcript levels, as compared with the control, in a time-dependent manner during the differentiation of MDPC-23 cells. Chitosan also significantly downregulated ON mRNA expression and accelerated mineralization in differentiating MDPC-23 cells. These results suggest that chitosan facilitates odontoblast differentiation and mineralization and may have potential clinical applications as a dentin regeneration material.
        4,000원
        54.
        2010.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report relative proper motion measurements of H2O masers in massive star-forming region W51 Main, based on data sets of VLBI observations for H2O masers at 22 GHz with Japanese VERA telescopes from 2003 to 2006. Data reductions and single-beam imaging analysis are to measure internal kinematics of maser spots and eventually to estimate the three-dimensional kinematics of H2O masers in W51 Main. Average space motions and proper motion measurements of H2O masers are given both graphical and in table formats. We find in this study that W51 Main appears to be associated with hyper-compact H II region with multiple massive proto-stars whose spectral types are of late O.
        4,600원
        55.
        2009.06 구독 인증기관 무료, 개인회원 유료
        L-trans-pyrrolidine-2,4-dicarboxylate (PDC) is a potent inhibitor of glutamate transporters. In our current study, we investigated whether the neuronal death induced by PDC involves mechanisms other than excitotoxicity in mixed mouse cortical cultures. Cortical cultures at 13-14 days in vitro were used and cell death was assessed by measuring the lactate dehydrogenase efflux into bathing media. Glutamate and PDC both induced neuronal death in a concentration-dependent manner but the neurotoxic effects of glutamate were found to be more potent than those of PDC. Treatment with 10, 100 and 200 M PDC equally potentiated 50 M glutamate-induced neuronal death. The neuronal death induced by 75 M glutamate was almost abolished by treatment with the NMDA antagonists, MK-801 and AP-5, but was unaffected by NBQX (an AMPA antagonist), trolox (antioxidant), BDNF or ZVAD-FMK (a pan-caspase inhibitor). However, the neuronal death induced by 200 M PDC was partially but significantly attenuated by single treatments with MK-801, AP-5, trolox, BDNF or ZVAD-FMK but not NBQX. Combined treatments with MK-801 plus trolox, MK-801 plus ZVAD-FMK or MK-801 plus BDNF almost abolished neuronal death, whereas combined treatments with trolox plus ZVADFMK, trolox plus BDNF or ZVAD-FMK plus BDNF did not enhance the inhibitory action of any single treatment with these drugs. These results demonstrate that the neuronal death induced by PDC involves not only in the excitotoxicity induced by the accumulation of glutamate but also the oxidative stress induced by free radical generation. This suggests that apoptotic neuronal death plays a role in PDCinduced oxidative neuronal injury.
        4,000원
        56.
        2009.06 구독 인증기관 무료, 개인회원 유료
        The rapid change of information and communication technologies (ICT) has resulted in a new gap, a digital divide between countries that can easily access ICT and digital information, and countries that lack accessibility of emerging information and communication technologies. Realizing the gap of digital divide through education, Korea launched a collaborative program called ‘APEC Cyber Education Network (ACEN)’ in 2001, targetting two economies: Indonesia and Thailand. This program provided workshops via ACEN Internet Volunteers (AIV) for training of the teachers’ capacity for economies’ beneficiary in the education of ICT. In 2003, this program has evolved into APEC Learning Community Builders (ALCoB) Internet Volunteers (AIV) program, and has continued until 2008. In this paper, we report our 8 years of experiences in collaboration between Korea and Indonesia through volunteers, and show the implications of a successful international cooperation model to overcome the digital divide between countries.
        4,600원
        57.
        2008.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have investigated the optical properties of the global haze on Titan from spectra recorded between 7100 and 9200Åwhere CH4 absorption bands of various intensities occur. The Titan spectra were obtained on Feb. 23, 2005 (UT), near the times of the Cassini T3 flyby and Huygens probe, using an optical echelle spectrograph (BOES) on the 1.8-m telescope at Bohyunsan Observatory in Korea. In order to derive the optical properties of the haze as a function of altitude, we developed an inversion radiative-transfer program using an atmospheric model of Titan and laboratory CH4 absorption coefficients available from the literature. The derived extinction coefficients of the haze increase toward the surface, and the coefficients at shorter wavelengths are greater than those at longer wavelengths for the 30 - 120 km altitude range, indicating that the Titanian haze becomes optically thin toward the longer wavelength range. Total optical depths of the haze are estimated to be 1.4 and 1.2 for the 7270 -7360Åand 8940 -9150Å ranges, respectively. Based on the Huygens/DISR data set, Tomasko et al. (2005) reported total optical depths of 2.5 - 3.5 at 8290Å depending on the assumed fractal aggregate particle model. The total optical depths based on our results are smaller than those of Tomasko et al., but they partially overlap with their results if we consider a large uncertainty from possible variations of the CH4 mixing ratio over Titan's disk. We also derived the single scattering albedo of the haze particles as a function of altitude: it is less than 0.5 at altitudes higher than ~150Km the average particle radius is smaller than the wavelengths, whereas near the surface, it becomes comparable or greater.
        4,300원
        58.
        2007.04 KCI 등재 구독 인증기관·개인회원 무료
        Sulfur is commonly used in Asia as an herbal medicine to treat inflammation and cancer , a nd potent chemo preventi ve effects have been demons tra ted in various in vivo and in vitromodels for s ul fur-containing compounds found in natura l1y occurring product s. Here, we 1'eport the growth inhibitory and apoptosis-related effects of a n ewly developedhigh-puri ty edible sulfur(ES) on immo1'tali zed human o1'al ke1'atinocytes(IHOKs) and on oral cancer cells representing two stages of oral cancer (HN4‘ HN12) based on an 3-(4,5-Dimethylthiazol-2-yl) -2.5- diphe n yltetrazolium bromide(MTI) assay, Western blotting, cell cycle analysis, and nuclear staining. The puri ty of the ES used in thi s study was ve1'ified by high performance liquid chromatog1'aphy (HPLC) , ami no acid analysis and energy dispersive spectroscopy(EDS). ES inhibited the prolife1'ation of imrnortalized and ma lig nant o1'al kerati nocytes in a dose- and time-dependent manne1' FITC-Annex.in V staining, DNA fragmentation t esting. and Hoechst 33258 s taining revealed that ES inhibits cell growth via apoptosis. ES bl ocked cell-cycle prog1'ession at t he sub-Gl phase‘ wi th decreased expression of cyclins Dl, D2‘ and E, and their activating partn ers cdk2‘ cdk4‘ and cdkfì, and a concomitant induction of p53 and p21/WAF1. Furthe1'more, ES treatment in creased the cytosolic level of cytochrome c and resulted in caspase- 3 activation‘ and thi s effect was co1'1'elated with Bax up-regulation and Bcl-2 down-1'egulation Taken together‘ these data suggest that ES is a potential chemopreventive and chemotherapeut ic agent fo r oral ca ncer
        60.
        2005.10 KCI 등재 구독 인증기관·개인회원 무료
        1'0 determine Lhe ll1echanism of cell c1eath incluced by iron chelators. we explored the pathways of the three structurally relatecl ll1 itogen-activatecl protein(MAP) kinase subfami li esduring iron cbelator- inclucecl apoptosis ancl differentiation of oral precancerous ancl cancel‘ cells. The iron chelator c1 eferoxamine(DFO) exertecl potent timeancl c1ose-c1epenclent inhi bitory effects on the growth of IHOK and HN4 cells The major mechanism of growth inhibition following DFO treatment was fOllncl to be apoptosis incluction. as assessecl by annexin V-FITC staining. cell cycle analysis‘ DNA lacldering, a ncl Hoechst staining. We report that DF'O s trongly activates the p38 MAP kinase and extracell ular signal- regu lated kinase(ERK). but c10es not activate the c-Jun N-terminal kin ase/ stl않s-activaLecl protein kinase(JNK/8APK) . Of the three MAP kinase blockers usecl‘ the selective p38 MAP kinase inhibitor 8ß203580 ancl ERK inhibitor PD98059 protected oral premaIignant ancl malignant cells againsL iron chelator- nclllced cell death. which incl icates that the p38 MAP kinase serves as a major mecliator 01' apoptos is induced by this iron chelator DFO also evoked the release of cytochrome c from mitochondria, and incluced the activation of caspase-3 ancl caspase-8 in oral cancer cells, which suggests that apoptosis occurs via the mi tochoncl ri on - mecl iaLed pathway. DFO enhanced the expression of Bax in IHOK ancl HN4 cells. consistent witll thei r p53 status Moreover. DFO downregulatecl the expression 01' Bcl-2 in oral cancer cells. which suggests that DFO- incluced apoptos is 01' oraJ cancer and precancerous cells may be mediatecl by an increase in the ratio of pro-apoptotic to anti-apoptotic proteins. ln terestingJy, trcatmcnt 01' IHOK ancl HN4 cel ls with 8B203580 abolishecl cytochrome c release‘ as wel l as the activation of caspase-3 and caspase-8. DFO suppressecl the expression of epithelial di ffe rentiation markers, such as involucrin, t ransglutaminase II. CK6. and CK19. ancl this suppression was blockecl by p38 ancl ERK MAP kinase ll1hlbltors The oral premalignant(IHOK) ancl malignant cell s(I-lN4) showed differential responses to DFO with respect to the expression of cel l cycle regulatory proteins. cell growth. ancl apoptosis. Coll ectively. the current study reveals that p38 MAP kinase plays an ill1 portant role in iron chela tor-mecliatecl cel l cleath and in the suppression of differentiation of oral premalignantandmalignanLcell s.by activating a c10wnstream apoptotic cascade that executes the ceIl c1eath pathway
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