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        검색결과 10,095

        5241.
        2010.03 구독 인증기관 무료, 개인회원 유료
        Human fibroblasts that maintain the structural integrity of connective tissues by secreting precursors of the extracellular matrix are typically cultured with serum. However, there are potential disadvantages of the use of serum including unnatural interactions between the cells and the potential for exposure to animal pathogens. To prevent the possible influence of serum on fibroblast cultures, we devised a serum-free growth method and present in vitro data that demonstrate its suitability for growing porcine fetal fibroblasts. These cells were grown under four different culture conditions: no serum (negative control), 10% fetal bovine serum (FBS, positive control), 10% knockout serum replacement (KSR) and 20% KSR in the medium. The proliferation rates and viabilities of the cells were investigated by counting the number of cells and trypan blue staining, respectively. The 10% FBS group showed the largest increase in the total number of cells (1.09 × 105 eell₃/ml). In terms of the rate of viable cells, the results from the KSR supplementation groups (20% KSR:64.7%; 10% KSR: 80.6%) were similar to those from the 10% FBS group (68.5%). Moreover, supplementation with either 10% (30 × 104 eell₃/ml) or 20% KSR (4.8 × 104 cells/ml) produced similar cell growth rates. In conclusion, although KSR supplementation produces a lower cell proliferation rate than FBS, this growth condition is more effective for obtaining an appropriate number of viable porcine fetal fibroblasts in culture. Using KSR in fibroblast culture medium is thus a viable alternative to FBS.
        4,000원
        5243.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        원자전달 라디칼 중합을 이용하여 polystyrene-b-poly(oxyethylene methacrylate) (PS-b-POEM) 블록 공중합체를 합성하고, FT-IR을 통해 중합이 성공적으로 이루어졌음을 확인하였다. 또한 자기 조립된 블록 공중합체 막을 제조한 후, 전구체 AgCF3SO3 도입과 UV 조사를 통해 고체상에서 은 나노입자를 성장시켰다. TEM 전자현미경과 UV-visible 분광학 분석을 통해 블록 공중합체 막의 내부에 은 나노입자가 형성된 것을 확인하였고, 또한 친수성 POEM 영역의 함량을 조절함으로써 나노입자의 크기를 조절할 수 있었다. 금속 나노입자를 제조하는 데 있어서 POEM 함량이 적은 블록 공중합체가 더 효과적임을 확인하였다.
        4,000원
        5245.
        2010.03 구독 인증기관 무료, 개인회원 유료
        Iron catalyzes the production of free radicals, which can be related to a variety of pathological events, such as cancer and aging. The effect of dietary iron was investigated on formation of colonic aberrant crypt foci (ACF) induced by azoxymethane in male F344 rats. Animals were fed three different diets, including iron-deficient (3 ppm Fe), iron-normal (35 ppm Fe), and iron-overloaded (350 ppm Fe) diets for eight weeks. During the first and second weeks of the experiment, animals received two subcutaneous injections of azoxymethane (AOM, 15 mg/kg body weight) to induce ACF. After staining with methylene blue, the total numbers of ACF and aberrant crypts (AC) were counted on the colonic mucosa. Analysis of blood and serum was performed using a blood cell differential counter and an automatic serum analyzer. Iron-deficient diets induced a significant decrease in red blood cell counts and the values of hemoglobin concentration, hematocrit, mean corpuscular hemoglobin, and mean corpuscular volume, while an iron-overloaded diet did not affect these values. The iron-overloaded diet induced an increase in deposits of iron in the liver of rats, as determined by the ICP method and Perl’s staining. The numbers of ACF per colon showed a slight increase in iron-overloaded or iron-deficient rats, without statistical significance, compared to iron-normal rats. The number of total AC per colon in iron-overloaded rats was significantly higher than that in iron-normal rats (p<0.05). The number of large ACF (≥ 4 AC per ACF) in iron-overloaded rats was also significantly higher than that in iron-normal rats (p<0.05). These results suggest that dietary iron intake may play an important role in colon carcinogenesis in humans and animals.
        4,200원
        5246.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The family Coniopterygidae belonging to Neuroptera with Semidalis aleyrodiformis (Stephens) is introduced from the Korean Peninsula in the present study. Taxonomic descriptions of the family and the species and illustrations of its wing and male genitalia are presented.
        4,000원
        5248.
        2010.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        C-Reactive protein (CRP), which is an 118 kDa pentameric protein, was secreted by the liver is an important biomarker for coronary disease, hypertension and inflammation. In this study, a method for CRP detection exploiting quantum dot (Qdot)-antibody conjugate was developed according to an indirect-competitive immunosensing protocol. For this purpose, a streptavidin-bound Qdot605 was linked with a separately prepared biotinylated monoclonal antirat CRP antibody to produce a Qdot-antibody conjugate. The immunosensing was performed at 0.1 and 20 nM of the coating antigen and conjugate, respectively. The current method was found very sensitive in CRP detection, judging from the concentration-dependent fluorescence emission.
        4,000원
        5249.
        2010.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Methylene blue (MB) was degraded by TiO2 and ZnO deposited on an activated carbon fiber (ACF) surface under UV light. The ACF/TiO2 and ACF/ZnO composites were characterized by BET, SEM, XRD, and EDX. The BET surface area was related to the adsorption capacity for composites. The SEM results showed that titanium dioxide and zinc oxide are distributed on the ACF surface. The XRD results showed that the ACF/TiO2 and ACF/ZnO composites contained a unique anatase structure for TiO2 and a typical hexagonal phase for ZnO respectively. These EDX spectra showed the presence of peaks of Ti element on ACF/TiO2 composite and peaks of Zn element on the ACF/ZnO composite. The blank experiments for either illuminating the MB solution or the suspension containing ACF/TiO2 or ACF/ZnO in the dark showed that both illumination and the catalyst were necessary for the mineralization of organic dye. Additionally, the ACF/TiO2 composites proved to be efficient photocatalysts due to degradation of MB at higher reaction rates. The addition of an oxidant ([NH4]2S2O8) led to an increase of the degradation rate of MB for ACF/TiO2 and ACF/ZnO composites.
        4,000원
        5250.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to evaluate job stress factors of school food service nutritionists according to the number of years they have worked. The subjects of this survey included 125 nutritionists (69 from full-time employees and 56 from part-time nutritionists) from elementary school, middle school, and high school in the Gangwon area. The results showed that stress related to duty was the top job stress factor, followed by environment-related stress, personal stress, organizationrelated stress and stress caused by human relations. In terms of the degree of stress, part-time nutritionists have more stress compared to full-time nutritionists. This was especially true for nutritionists that had been employed for one year. In this case, the degree of stress was much higher than long time employed nutritionists. In terms of how to deal with job stress, school nutritionists eliminated stress directly (with direct countermeasures). In order to deal with stress, workers expected stable employment such as pay (wages), promotions, etc. In particular, part-time school nutritionists had stronger expectations. When correlation between job stress factors were examined, environment-related, duty-related, organization-related, human relations-related and personal stress were all shown to be mutually related.
        4,200원
        5251.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dahi is yoghurt like fermented dairy products available in Bangladesh made by traditional ways from raw milk. The aim of the present study was to check and compare the present quality status of the market dahi in reference to laboratory made dahi. For this, dahi was prepared in the laboratory (A) and collected from Kishoregonj district (B), Gazipur district (C), Bogra district (D) and Dhaka district (E and F). Consumer acceptance quality was judged on 100 point by a judge panel and chemical and microbiological quality test were done by established methods. ‘A’ type dahi was superior followed by E, D, F, B and C considering the consumer acceptance quality parameter. From chemical test, it appears that, B possess the lowest pH (3.75 ± 0.05) and highest was in C (4.46 ± 0.15). Total solids content of F type dahi (318.40 ± 4.44 g/kg) was highest and fat (52.00 ± 2.00 g/kg), protein (44.33 ± 2.00 g/kg) and ash (10.76 ± 0.31 g/kg) content were also higher in F type dahi. E and A type dahi were also with considerable figure in chemical quality parameter. Dahi B was inferior in respect of microbiological quality- total viable count (TVC) (× 105 cfu/ml) content was 94.00 ± 4.58, yeast (cfu/ml) content was 183.33 ± 15.28 and mold (cfu/ml) content was 53.33 ± 15.28. The TVC (× 105 cfu/ml), yeast (cfu/ml) and mold (cfu/ml) content of A type dahi were 39.67 ± 4.51, 50.00 ± 10.00 and 20.00 ± 10.00, respectively. Considering all the three major quality aspects dahi A was superior than others followed by F, D, E, C and B.
        4,000원
        5252.
        2009.12 구독 인증기관 무료, 개인회원 유료
        Human mesenchymal stem cell (hMSCs) isolated from human adult bone marrow have self-renewal capacity and can differentiate into multiple cell types in vitro and in vivo. A number of studies have now demonstrated that MSCs can differentiate into various neuronal populations. Due to their autologous characteristics, replacement therapy using MSCs is considered to be safe and does not involve immunological complications. The basic helix-loop-helix (bHLH) transcription factor Olig2 is necessary for the specification of both oligodendrocytes and motor neurons during vertebrate embryogenesis. To develop an efficient method for inducing neuronal differentiation from MSCs, we attempted to optimize the culture conditions and combination with Olig2 gene overexpression. We observed neuron-like morphological changes in the hMSCs under these induction conditions and examined neuronal marker expression in these cells by RTPCR and immunocytochemistry. Our data demonstrate that the combination of Olig2 overexpression and neuron-specific conditioned medium facilitates the neuronal differentiation of hMSCs in vitro. These results will advance the development of an efficient stem cell-mediated cell therapy for human neurodegenerative diseases.
        4,000원
        5253.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate insect fauna in the four insect garden sites of Suwon, Yeongyang, Buyeo and Yecheon from 2005 to 2007. Seasonal population size of insects was largest from June to August in all the four sites. In the four sites, Coleopteran insects were dominant followed by Hemiptera and Orthoptera. Unique education/learning programs are successfully run at the insect gardens based on the three geographic types (i.e. urban, mountainous and rural). These activities will help preserve insect biodiversity in the area and visitors better understand life forms such as insects found in the areas.
        4,000원
        5255.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The biological effects of carcinogenic polycyclic aromatic hydrocarbons (cPAHs) including benzo[a]pyrene (BaP), dibenzo[a,h]anthracene (DBA), benzo[a]anthracene (BaA), benzo[b] fluoranthene (BbF), benzo[k]fluoranthene (BkF), and indeno[1,2,3-c, d]pyrene (
        4,000원
        5256.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Epoxy resin based encapsulants are widely used in semiconductor packaging applications. Epoxy resin based encapsulants are often subject to crack or delamination during the reliability test due to the thermal stress caused by high modulus nature of epoxy resins. Epoxy functional siloxanes are often added into epoxy resin to reduce the modulus so that the thermal stress can be reduced. Epoxy functional siloxanes, additives for reduced modulus, were synthesized and added into the curable epoxy resins. The modulus and the coefficient of thermal expansion (CTE) were also measured to investigate the thermal stress and to see whether the epoxy functional siloxane adversely affects the CTE or not. As a result, around 26% to 72% of thermal stress reduction was observed with no adverse effect on CTE.
        4,000원
        5257.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Poly propylene carbonate (PPC)와 cloisite 20B (PPC/C-20B)을 solution method를 통하여 합성하였고, 이를 통해 합성된 나노 조성물의 morphology, 열적 특성, 수분 흡수의 특성을 평가하였다. 나노 조성물의 구조는 X-ray diffraction (XRD) 로 확인하였고, 열적 특성은 thermal gravimetric analysis (TGA)와 differential scanning calorimetric (DSC)를 이용해 분석하였다. TGA와 DSC의 결과를 통해 나노 조성물은 기존의 PPC에 비해 높은 열적 안정성을 가짐을 확인할 수 있었다. DSC측정에서 5 wt%의 clay를 포함한 nanohybrid의 유리전이온도는 순수한 PPC의 21℃에서 30℃로 9℃ 증가하였고, TGA 측정을 통해 확인한 열분해온도(Td50%)는 순수 PPC에 비해 23℃가 높아졌음을 확인하였다. 또한 PPC 나노 조성물의 수분 흡수량은 기존의 PPC에 비해 상당히 감소하였다. 이는 clay의 PPC matrix 구조 내에 존재함으로 인해 수분 흡수를 감소시킨 것으로 해석할 수 있다. 수분 흡수는 코팅 막의 분해를 유발하고 물리적, 기계적 성능에 영향을 미친다. 따라서 나노 조성물로 인한 PPC의 열적 안정성, 수분흡수도 향상은 PPC의 사용과 실제 공정에 중요한 변수로 작용할 수 있다.
        4,000원
        5258.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This cycloaddition of [70]fullerene with methyl azidoacetate in benzene under ultrasonic irradiated condition afforded the closed [5,6]-bridged aziridino[70]fullerene derivative, which was unusual product of cycloaddition to the 5,6-junction of fullerene. Its structure was determined by FAB-MS, UV-vis, 1H- and 13C-NMR spectral data. The closed [5,6]-bridged aziridino[70]fullerene-functionalized gold nanoparticle films were self-assembled using the layer-by-layer method on the reactive of glass slides functionalized with 3-mercaptopropyl trimethoxysilane. The functionalized glass slides were alternately soaked in the solution containing closed the [5,6]-bridged aziridino[70]fullerene and 4-aminothiophenoxide/hexanethiolate-protected gold nanoparticles. The closed [5,6]-bridged aziridino[70]fullerene-functionalized gold nanoparticle films have grown up to 5 layers depending on the immersion time. The self-assembled nanoparticle multilayer films were characterized using UV-vis spectroscopy showed that the surface plasmon band of gold at 527 nm gradually became more evident as successive layers were added to the films.
        3,000원
        5259.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        원자전달 라디칼 중합을 이용하여 polystyrene-b-poly (hydroxyethyl methacrylate) (PS-b-PHEMA) 블록 공중합체를 합성한 뒤, 블록 공중합체의 -OH 그룹과 이미다졸 디카르복실릭산 (IDA)의 -COOH 그룹과의 에스테르 반응에 의하여 가교된 전해질막을 제조하였다. 인산(H3PO4)을 도핑하여 이미다졸-인산 착체를 형성한 결과, 인산 함량이 증가함에 따라 공중합체 전해질막의 수소 이온 전도도가 계속 증가하였다. 또한 인장강도와 인장률 모두 인산 함량에 따라 증가하였다. 특히 [HEMA]: [IDA]:[H3PO4] = 3:4:4의 조성을 갖는 PS-b-PHEMA/IDA/H3PO4 블록 공중합체 전해질막은 100°C의 비가습 조건에서 최대 0.01 S/cm의 수소이온 전도도를 나타내었다. 열분석(TGA) 실험을 통하여 전해질막은 350°C의 고온까지 열적으로 안정함을 확인하였다.
        4,000원
        5260.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Thermal emissivity of nuclear graphite was measured with its oxidation degree. Commercial nuclear graphites (IG-110, PECA, IG-430, and NBG-18) have been used as samples. Concave on graphites surface increased as its oxidation degree increased, and R value (Id/Ig) of the graphites decreased as the oxidation degree increased. The thermal emissivity increased depending on the decrease of the R (Id/Ig) value through Raman spectroscopy analysis. It was determined that the thermal emissivity was influenced by the crystallinity of the nuclear graphite.
        4,000원