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        검색결과 9,514

        5741.
        2009.03 구독 인증기관 무료, 개인회원 유료
        Placenta is the main nutrition source for the fetus during pregnancy. Thus, it has a pivotal function in the pregnant process. Many functions of the placenta have been elucidated. An abnormal placenta is associated with a high rate of pregnancy failure in somatic cloned bovine. Differentially expressed genes (DEGs) were examined in a comparison between normal and cloned bovine placenta using annealing control primer (ACP)-based GeneFishing PCR. Using 120 ACPs, nearly 80 genes were identified and the fragments of 42 DEGs were sequenced. 38 of these genes were known genes and four were unknown. To determine the DEGs result, six target clones expressing on one-side of a normal and a clone placenta were selected. Through an analysis of the target genes using the real-time PCR, the expressing pattern was found to be somewhat different from the DEGs. Additionally, several genes appeared with the same expression pattern. Taken together, this suggests that the target genes would be essential for research into what influences the placental formative mechanisms during fetal development.
        4,000원
        5742.
        2009.03 구독 인증기관 무료, 개인회원 유료
        The attachment and adhesion of RAW 264.7 and MC3T3-E1 cells to titanium (Ti) discs with various degrees of roughness was investigated. The attachment, adhesion, and proliferation of these cells were evaluated after 4 hr, 24 hr and 7 day incubations. Both RAW 264.7 and MC3T3-E1 cells showed a time-dependant correlation between attachment and adhesion on the surface of the titanium discs. Both types of cells tended to have higher survival rate on these discs as the surface roughness increased. The percentage of adherent inflammatory RAW 264.7 cells was greater than MC3T3-E1 cells at 24 hr, but this was reversed at 7 days in culture. The morphology of osteoblastic MC3T3-E1 cells at 24 hr, determined using a surface emission microscope (SEM), appeared flattened and spread out while inflammatory RAW 264.7 cells were predominantly spherical in shape. The adhesion of both cell types on the titanium discs was dependant on the levels of fibronectin adsorbed on the disc surface, indicating that serum constituents modulate the efficient adhesion of these cells. Our data indicate that the cellular response to the titanium surface is dependent on the types of cells, surface roughness and serum constituents.
        4,000원
        5743.
        2009.03 구독 인증기관 무료, 개인회원 유료
        Cyclosporin A (CsA) has been used clinically as an immunosuppressive drug to prevent organ transplant rejection and in basic research as a mitochondrial permeability blocker. It has been reported that CsA has a protective role in severed neurons and a neurotrophic effect in neuronal cells. However, the molecular mechanisms underlying the stimulation of neuronal cell proliferation by CsA have not yet been elucidated. In our current study, we investigated CsA responsive proteins in PC12 cells using a systematic proteomic approach. The viability of these cells following CsA treatment increased in a dose- and time-dependent manner. Proteins in the CsA-treated PC12 cells were profiled by two-dimensional gel electrophoresis (2-DE) and identified by matrix-assisted laser desorption ionization time-of flight (MALDI-TOF) and electrospray ionization quadupole time-of-flight mass spectrometries (EIQ-TOFMS). This differential expression analysis showed significant changes for 10 proteins (6 up-regulated and 4 down-regulated) upon CsA treatment that were related to cell proliferation, metabolism and the stress response. These proteomics data further our understanding of the proliferation mechanisms of PC12 cells exposed to CsA and demonstrate that our methodology has potential to further elucidate the mechanisms and pathways involved.
        4,000원
        5744.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Transcriptomic changes in the brain of Limanda yokohamae were investigated to understand the environmental condition of Masan Bay, Korea. Differentially expressed genes (DEGs) in the brain of the flat fish from Masan Bay were identified by comparing those
        4,000원
        5746.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to find a correlation between XRD and Raman result of the oxidized high modulus carbon fibers as a function of its oxidation degrees, and compare with the isotropic carbon fiber reported early. La of the high modulus carbon fiber prepared by oxidation in carbon dioxide gas have been observed using laser Raman spectroscopy. The basic structural parameters of the fibers were evaluated by XRD as well. The La of the original high modulus carbon fibers were measured to be 144 a from Raman analysis and 135 a from XRD analysis. La of the 92% oxidized fiber were 168 a by using Raman and 182 a by using XRD. There was some correlation between the La value obtained from Raman and XRD. However the La value changes of the high modulus carbon fiber through whole oxidation process showed opposite tendency compare with the isotropic carbon fiber because of the fiber structure basically.
        4,000원
        5747.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated carbon (AC) is one of the most effective adsorbents for organic compounds because of their extended surface area, high adsorption capacity, microporous structure and special surface reactivity. The composites of pH-sensitive hydrogel and activated carbon were prepared in order to improve the loading capacity of drug. The pH-sensitive hydrogel matrix swelled well in the basic condition to release the drug loaded in AC. The release of drug was controlled depending on both the pH due to the ionization of the carboxylic acid group and the AC due to the surface properties.
        4,000원
        5748.
        2009.03 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate effect of herbal extracts mixtures on hair growth in an alopecia model of C57BL/6 mice. There were 4 experimental groups including distilled water (DW, negative control), 25% ethanol(EtOH, vehicle control) and two herbal extract mixtures (HE-1 and HE-2). HE-1 included Polygonum and Brassica campestris extracts and HE-2 included Mulberry root and Gardenia extracts. The 6 weeks-old C57BL/6 male mice were shaved with an electric clipper and the test compounds were topically treated with 0.2 ml per mouse daily for 3 weeks. The hair re-growth was photographically determined at days 0, 4, 7, 10, 14, 17, and 21. The number of mast cells which is an important modulator of hair growth was counted in 1 cm of dorsal skin section of mice. There were no clinical signs in all experimental groups. As the results of photometric analysis, the topical application of the herbal extracts (HE-1 & 2) for 2 weeks to dorsal skin accelerated hair re-growth remarkably faster than that of DW group (p<0.05). Activity of alkaline phosphatase (ALP) was significantly increased in EtOH group compared to DW group (p<0.05). Both herbal extract mixtures also increased the ALP activity, but it was not significantly different from DW. Treatment of mice with HE-2 significantly increased mast cell population compared to EtOH. Taken together, these results suggest that herbal extract mixtures used in this study may have hair-growth promoting activities and can be useful for treatment for male pattern baldness or alopecia in humans.
        4,000원
        5749.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We measured the degree of macrodispersion of the various single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) using UV-VIS-NIR absorption spectroscopy. CNTs were dispersed with SDS of 2 wt % in deionized water using the homogenizer and then were further centrifugated at 6000 g for 10 min. The degree of macrodispersion, expressed by Dm(λ)=Aa(λ)/Ab(λ)*100 (%), where λ is the wavelength and Aa(λ) and Ab(λ) are the absorbance of the sample after and before centrifugation, respectively. In the case of MWCNTs, we evaluated the degree of macrodispersion by the average degree of macrodispersion (Dm(λ)) between 1000 and 1200 nm. The degree of macrodispersion of SWCNTs was evaluated at the wavelength in which van Hove singularity-related transition regions were excluded, i.e., the range was chosen between E11S and E22S peaks. We have estimated six samples with the same method. The standard deviation of each sample was lower than 5. Therefore, we presented a reliable evaluation method for the macrodispersion of CNTs for standardization.
        4,000원
        5750.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We propose an evaluation method of the relative content of single-walled carbon nanotubes (SWCNT) in SWCNT soot synthesized by arc discharge using UV-VIS-NIR absorption spectroscopy. In this method, we consider the absorbance of semiconducting and metallic SWCNTs together to calculate the relative content of SWCNTs with respect to a highly purified reference. Our method provides the more reliable and realistic evaluation of SWCNT content with respect to the whole carbonaceous content than the previously reported method.
        4,000원
        5751.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We measured the non-carbon content of single-walled carbon nanotubes (SWCNTs) in SWCNT soot using thermogravimetric analysis. The weight increased percentage by the oxidation of metal in the raw soot is well obtained by TGA graph which was confirmed with ICP-AES, XRD, and XPS. This work will be very useful for the purity precise evaluation of SWCNT with UN-vis-NIR spectroscopy.
        3,000원
        5752.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, standardization trends related carbon nanotubes and international standardization activities in the ISO/TC229 and IEC/TC113 were introduced. The movement toward development of carbon nanotube standard began in the nanotechnology council under the IEEE in 2005. KATS has also run the carbon nanotube standardization committee to support commercialization of product containing carbon nanotube through standards since 2004. The Korean Standards such as KSD2711, 2712, 2717 were established.
        3,000원
        5754.
        2009.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The e-CALLISTO is a global network of frequency-agile solar radio spectrometers that was constructed in a collaboration between Swiss Federal Institute of Technology Zurich (ETH Zurich) and local host institutes. It is intended to monitor solar radio bursts 24 hours a day in frequency range between 45 MHz and 870 MHz. One of e-CALLISTO spectrometer was installed at Korea Astronomy and Space Science Institute (KASI) in 2007 October. The spectrometer gets signals from a horizontally polarized log-periodic antenna mounted on an automatic Sun-tracking system. Tracking status and data are monitored in Space Weather Monitoring Laboratory (SWML) of KASI in real time, and flare time data are transferred to ETH Zurich data archive daily. Using this spectrometer we obtained a couple of type II solar radio bursts on 2007 December 31, and found that these bursts are associated with a CME which occurred on the east limb.
        4,000원
        5755.
        2008.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Well-aligned Zinc oxide (ZnO) nanowires were synthesized on silicon substrates by a carbothermal evaporation method using a mixture of ZnO and graphite powder with Au thin film was used as a catalyst. The XRD results showed that as-prepared product is the hexagonal wurzite ZnO nanostructure and SEM images demonstrated that ZnO nanowires had been grown along the [0001] direction with hexagonal cross section. As-grown ZnO nanowires were coated with glucose oxidase (GOx) for glucose sensing. Glucose converted into gluconic acid by reaction with GOx and two electrons are generated. They transfer into ZnO nanowires due to the electric force between electrons and the positively charged ZnO nanostructures in PBS. Photoluminescence (PL) spectroscopy was employed for investigating the movements of electrons, and the peak PL intensity increased with the glucose concentration and became saturated when the glucose concentration is above 10 mM. These results demonstrate that ZnO nanostructures have potential applications in biosensors.
        3,000원
        5756.
        2008.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        6,400원
        5757.
        2008.12 구독 인증기관 무료, 개인회원 유료
        Several lines of evidence suggest that osteocytes play a critical role in bone remodeling. Both healthy and apoptotic osteocytes can send signals to other bone surface cells such as osteoblasts, osteoclasts, osteoclast precursors, and bone lining cells through canalicular networks. Osteocytes responding to mechanical strain may also send signals to other cells. To determine the role for osteocytes an mechanical strain in bone remodeling, we examined the effects of fluid flow shear stress on osteoclast precursor cell and osteoblast proliferation and recruitment induced by osteocytes. In addition, the effects of fluid flow shear stress on osteocyte M-CSF, RANKL, and OPG mRNA expression were also examined. MLO-Y4 cells were used as an in vitro model for osteocytes, RAW 264.7 cells and MOCP-5 cells as osteoclast precursors, and 2T3 cells as osteoblasts. MLO-Y4 cells conditioned medium (Y4-CM) was collected after 24h culture. For fluid flow experiments, MLO-Y4 cells were exposed to 2h of pulsatile fluid flow (PFF) at 2, 4, 8, 16±0.6dynes/cm² using the Flexcell StreamerTM system. For proliferation assays, MOCP-5, RAW 264.7, and 2T3 cells were cultured with control media or 10-100% Y4 CM. Cells were cultured for 3d, and then cells were counted. RAW 264.7 and 2T3 cell migration was assayed using transwells with control media or 10-100% Y4-CM. M-CSF, RANKL and OPG in MLO-Y4 mRNA expression was determined by semiquantitative RT-PCR. Y4-CM increased osteoclast precursor proliferation and migration, but decreased 2T3 cell proliferation and migration. CM from MLO-Y4 cells exposed to PFF caused decreased RAW 267.4 cell proliferation and migration and 2T3 migration compared to control Y4-CM. However, Y4-CM from cells exposed to PFF had no effect on 2T3 osteoblastic cell proliferation. PFF decreased RNAKL mRNA and increased OPG mRNA in MLO-Y4 cells compared to control(without PFF). PFF had no effect on M-CSF mRNA expression in MLO-Y4 cells. These results suggest that osteocytes can regulate bone remodeling by communication with osteoclast precursors and osteoblasts and that osteocytes can communicate mechanical signals to other cells.
        4,000원
        5758.
        2008.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        5,400원
        5760.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Eight Bacillus thuringiensis strains activated against mosquito larva were compared their characterization. Spherical-shaped parasporal inclusion of B. thuringiensis subsp. tohokuensis CAB167 was observed by phase-contrast microscopy and scanning electron microscopy. LC₅₀ values of B. thuringiensis subsp. tohokuensis CAB167 against Culex pipiens molestus, Culex pipiens pallens, and Aedes aegyti were 173, 190 and 580 ng/㎖, respectively. B. thuringiensis subsp. tohokuensis CAB167 had a parasporal inclusion containing 4 major protein components, for example, 135, 80, 49 and 28-kDa by SDS-PAGE. Otherwise, after trypsin digestion of parasporal inclusion, SDS-PAGE was showed new protease-resistant peptides at 72 and 63-kDa. Activated toxins of isolated CAB167 were different from other reference strains on a serological by immuno-diffusion test.
        4,000원