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        검색결과 984

        544.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,200원
        545.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, the CO2 adsorption behaviors of amine functionalized activated carbons (ACs) were investigated. The surface of ACs was modified with urea, melamine, diethylenetriamine (DETA), pentaethylenehexamine (PEHA), polyethylenimine (PEI), and 3-aminopropyl-triethoxysilane (ATPS). The various surface properties of amine functionalized ACs were characterized by Boehm's method, nitrogen full isotherms, XPS, and TGA analyses. The active ingredients impregnated on the ACs show significant influence on the adsorption for CO2 and its volumes adsorbed on amine functionalized ACs are larger than that on the pristine ACs, which is due to the grafted amine groups of the AC surfaces.
        3,000원
        546.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The electrochemical deposition of Pt nanoparticles on carbon nanotubes (CNTs) supports and their catalytic activities formethanol electro-oxidation were investigated. Pt catalysts of 4~12nm average crystalline size were grown on supports bypotential cycling methods. Electro-plating of 12min time by potential cycling method was sufficient to obtain smallcrystalline size 4.5nm particles, showing a good electrochemical activity. The catalysts’ loading contents were enhanced byincreasing the deposition time. The crystalline sizes and morphology of the Pt/support catalysts were evaluated using X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The electrochemical behaviors of the Pt/support catalystswere investigated according to their characteristic current-potential curves in a methanol solution. In the result, theelectrochemical activity increased with increased plating time, reaching the maximum at 12min, and then decreased. Theenhanced electroactivity for catalysts was correlated to the crystalline size and dispersion state of the catalysts.
        3,000원
        547.
        2009.09 구독 인증기관 무료, 개인회원 유료
        The role of Cl channels in regulatory volume decrease (RVD) in human salivary gland acinar cells was examined using a whole-cell patch clamp technique. Human tissues were obtained from healthy volunteers or from patients with oromaxillofacial tumors. During the measurements, K+-free solutions were employed to eliminate contamination of whole-cell conductance by K+ currents. When the cells were exposed to a 70% hypotonic solution, outward-rectifying currents, which were not observed in the resting state, were found to have significantly increased both in human labial and parotid gland acinar cells. The amplitudes of the currents were reduced in a low CI bath solution. Furthermore, the addition of 100μM 5-Nitro-2- (3-phenyl propylamino) benzoic acid (NPPB) or 100μM 4,4'-diisothio cyanatostilbene-2,2'-disulphonic acid (DIDS), known to partially block Cl channels, significantly inhibited these currents. Its outward-rectifying current profile, shift in reversal potential in a low Cl bath solution and pharmacological properties suggest that this is a Cα2+ independent, volume activated Cl current. We conclude therefore that volume activated Cl channels play a putative role in RVD in human salivary gland acinar cells.
        4,000원
        548.
        2009.08 구독 인증기관·개인회원 무료
        Barley is an important substrate for forage production in winter season of Korea. In this study, field trials were carried out to investigate the effects of harvest time and cultivar on the yield and quality of forage barleys developed in Korea. Four whole crop barley cultivars (Youngyang, Wooho, Yuyeon and Dami) were selected and harvested on five separate growth stages (heading, and intervals of 1, 2, 3, and 4 weeks after heading) in split plot design with three replications. Forage yield and nutritive value were determined. Results from this experiment indicated significant differences due to harvest time and cultivar in dry matter yield and total digestible nutrients (TDN) yield for forage. The interaction between harvest time and cultivar was not significant. The TDN yield trends were increasing with later harvest time due to higher dry matter yield and TDN content. This experiment provides some interesting results with respects to optimum harvest time, feed value and ultimately yield for the different whole crop barley cultivars.
        549.
        2009.06 구독 인증기관 무료, 개인회원 유료
        Chios gum mastic (CGM) is a resin produced from the stem and leaves of Pistiacia lentiscus L var chia, a plant which grows only on Chios Island in Greece. CGM has been used for many centuries as a dietary supplement and folk medicine for stomach and duodenal ulcers in many Mediterranean countries and is known also to induce cell cycle arrest and apoptosis in some cancer cells. In this study, we further investigated the induction and mechanisms underlying the apoptotic response to CGM treatment in the SCC25 human tongue squamous cell carcinoma cell line. The viability of SCC25 cells, human normal keratinocytes (HaCaT cells) and human gingival fibroblasts (HGF-1 cells), and the growth inhibition of SCC25 cells were assessed by MTT assay and clonogenic assay, respectively. Staining with Hoechst and hemacolor dyes and TUNEL assays were employed to detect SCC25 cells undergoing apoptosis. SCC25 cells were treated with CGM, and this was followed by western blotting, immunocytochemistry, confocal microscopy, FACScan flow cytometry, MMP activity and proteasome activity analyses. CGM treatment of SCC25 cells was found to result in a time- and dosedependent decrease in cell viability, a dose-dependent inhibition of cell growth, and apoptotic cell death. Interestingly, CGM showed a remarkable level of cytotoxicity in SCC25 cells but not in normal cells. Tested SCC25 cells also showed several lines of apoptotic manifestation. Taken together, our present findings demonstrate that CGM strongly inhibits cell proliferation by modulating the expression of G1 cell cycle-related proteins and induces apoptosis via the proteasome, mitochondria and caspase cascades in SCC25 cells.
        4,300원
        553.
        2008.12 구독 인증기관 무료, 개인회원 유료
        Bicuculline is one of the most commonly used GABAд eceptor antagonists in electrophysiological research. Because of its poor water solubility, bicuculline quaternary ammonium salts such as bicuculline methiodide (BMI) and bicuculline methbromide are preferred. However, a number of studies have shown that BMI has non-GABAд eceptor-mediated effects. The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) is implicated in the processing of nociceptive signaling. In this study, we investigated whether BMI has non-GABA receptor-mediated activity in Vc SG neurons using a whole cell patch clamp technique. SG neurons were depolarized by application of BMI (20M) using a high Cℓ⁻ipette solution. GABA ( 30-100μM) also induced membrane depolarization of SG neuron. Although BMI is known to be a GABAд receptor antagonist, GABA-induced membrane depolarization was enhanced by co-application with BMI. However, free base bicuculline (fBIC) and picrotoxin (PTX), a GABAд and GABAс receptor antagonist, blocked the GABA-induced response. Furthermore, BMI-induced membrane depolarization persisted in the presence of PTX or an antagonist cocktail consisting of tetrodotoxin (Nα+ nnel blocker),AP-5 (NMDA receptor antagonist), CNQX (non-NMDA receptor antagonist), and strychnine (glycine receptor antagonist). Thus BMI induces membrane depolarization by directly acting on postsynaptic Vc SG neurons in a manner which is independent of GABAд receptors. These results suggest that other unknown mechanisms may be involved in BMI-induced membrane depolarization.
        4,000원
        555.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The p-dioxanone can be used to make a variety of commercially useful products particularly where biodegradability is desired, such as fibers, sutures, molded articles, containers, medical devices and surgical clips, film and compostable trash bags. The mole fraction solubility of p-dioxanone in various solvents such as acetone, ethylacetate, tetrahydrofuran, methanol, ethanol, 1-propanol, 1-butanol and 1-pentanol were measured over the temperature range from 263.05 K to 288.45 K. The solubility of p-dioxanone increases with increasing polarity of the solvents.
        4,000원
        556.
        2008.12 구독 인증기관 무료, 개인회원 유료
        The techniques of IVM, IVF and IVC of canine oocytes may provide useful information for gamete salvage programs and the conservation of endangered canidae. This investigation has been made to determine the efficiency of in vitro maturation (IVM) as a basic experiment to study the development of canine oocytes after in vitro fertilization (IVF). The rate of oocytes developing to the MII stage was higher in the hormone treated group (10 IU/ml hCG+eCG, 14.7%, p<0.05) than in the control group (0 IU/ml hCG+eCG, 10.0%). The monospermy and pronuclear rates of canine oocytes were investigated after caffeine treatment on IVF. Canine oocytes were fertilized in the Fert‐TALP medium supplemented with 0, 10, 20 or 30 mM caffeine (Fert I, Fert II, Fert III or Fert IV, respectively). The highest pronuclear formation rate was obtained in the Fert I for 24 h IVF (6.7%, 6/89). Therefore, it is believed that unlike in other mammals, caffeine in canine IVF does not increase the efficiency of fertilization rate, and is not an important factor.
        4,000원