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        검색결과 876

        422.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mass production of graphene-based materials, which have high specific surface area, is of importance for industrial applications. Herein, we report on a facile approach to produce thermally modified graphene oxide (TMG) in large quantities. We performed this experiment with a hot plate under environments that have relatively low temperature and no using inert gas. TMG materials showed a high specific surface area (430 m2g-1). Successful reduction was confirmed by elemental analysis, X-ray photoelectron spectroscopy, thermogravimetic analysis, and X-ray diffraction. The resulting materials might be useful for various applications such as in rechargeable batteries, as hydrogen storage materials, as nano-fillers in composites, in ultracapacitors, and in chemical/bio sensors.
        3,000원
        423.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A rapid, simple and reliable LC-MS/MS method, which can be used on a routine basis, was developed for the simultaneous detection of 8 penicillin antibiotics (amoxicillin, ampicillin, penicillin-G, penicillin-V, oxacillin, cloxacillin, nafcillin and dicloxacillin) in swine muscle and kidney. The antibiotics were extracted from samples with water and methanol. The extract was centrifuged, filtered and analyzed by liquid chromatography coupled with a tandem mass spectrometer (LC-MS/MS), using a C18 reversed phase column with water/acetonitrile gradient containing 0.05 % formic acid. Mass spectral acquisition was achieved in an electrospray positive ion mode by applying multiple reaction monitoring (MRM) of 2 fragment ion transitions to provide a high degree of sensitivity and specificity. The ion rations were consistent and could be used for confirmation of identity of the penicillin antibiotics. Recoveries of eight penicillins at three fortification levels (10, 20 and 40㎍/㎏) ranged from 79.8 to 102.4% and 72.8 to 103.4% in swine muscle and kidney, respectively. The coefficient of variation was than 9% in all samples. The estimated limits of quantification (LOQs) ranged from 1.0 to 3.2㎍/㎏ in swine muscle and kidney, respectively. The LOQs of this method are below the MRLs of penicillin antibiotics in animal tissues established in Korea and other countries.
        4,000원
        428.
        2011.10 구독 인증기관·개인회원 무료
        429.
        2011.10 구독 인증기관·개인회원 무료
        Entomopathogenic fungus Aschersonia aleyrodis naturally occurred on citrus whitefly, Dialeurodes citri nymph was often observed in organic citrus orchards, Jeju. The genus Aschersonia is also known to be toxic against scale insects and other pests. However, little is known about artificial media for mass production of spores of Aschersonia species. Grains are excellent sources of media for mass conidia production of various entomopathogenic fungi. The yeast extract, which converts carbohydrates to carbon dioxides and alcohols, contains a large amount of vitamin B complexes which facilitate the carbohydrate metabolism. The more yeast extract content the more conidia production on artificial medium made from commercial corn flour and corn gluten feed. The number of conidium produced on oat, millet, sorghum, and unhulled barley medium containing 1% yeast extract were 1.8, 1.8, 1.6, and 2.1×1010/plate (90mm × 15mm), respectively. However, the greatest yeast effect among four media showed appeared on sorghum medium, which produced 25 times higher spore production than sorghum alone. Furthermore, the conidia from solid sorghum medium could be easily harvested with cell scraper.
        430.
        2011.10 구독 인증기관·개인회원 무료
        Proteomics may help to detect subtle pollution-related changes, such as responses to mixture pollution at low concentrations, where clear signs of toxicity are absent. Also proteomics provide potential in the discovery of new sensitive biomarkers for environmental pollution. We utilized SELDI-TOF MS (surface enhanced laser desorption. / ionization time-of-flight mass spectrometry) to analyze the proteomic profile of Heterocypris incongruens exposed to several heavy metals (lead, mercury, copper, cadmium and chromium) and pesticides (emamectin benzoate, endosulfan, cypermethrin, mancozeb and paraquat dichloride). Several highly significant biomarkers were selected to make a model of classification analysis. data sets obtained from H. incongruens exposed to pollutants were investigated for differential protein expression by SELDI-TOF MS and decision tree classification. Decision tree model was developed with training set, and then validated with test set from profiling data of H. incongruens. Machine learning techniques provide a promising approach to process the information from mass spectrometry data. Even thought the identification of protein would be ideal, class discrimination does not need it. In the future, this decision tree model would be validated with various levels of pollutants to apply field samples.
        431.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In general, zona pellucida (ZP) of the blastocyst has to be removed first, then either isolated the inner cell mass (ICM) or ZP-removed whole blastocyst, which is then cultured on the feeder layer to induce ICM outgrowth for the generation of embryonic stem cells (ESC). However, it is unclear whether ICM isolation before seeding on feeder layer is beneficial or not because the interaction between ICM and trophoblasts may affect cellular growth and/or pluripotency during the culture on the feeder. In the present study, two ZP removal methods (mechanically by splitting with a 28-gauge needle versus chemically by the treatment of acid-Tyrode's solution) and two ICM isolation methods (ZP-free whole blastocyst seeding versus mechanical isolation of ICM) were evaluated for the efficient isolation and culture of putative parthenogenetic bovine ESC. The number of maintained outgrown colonies was counted in each experimental group. As the result, mechanical removal of ZP with a needle and followed by whole ZP-free blastocyst seeding on feeder cells tended to attach more on the feeder layer and resulted in more outgrown colonies with its simple and less time-costing benefits. Currently we are generating ESC lines in HanWoo cattle by using this method for initial outgrowth of the parthenogenetic bovine blastocysts.
        4,000원
        432.
        2011.06 구독 인증기관 무료, 개인회원 유료
        본 연구는 기장군 전면해역에 설치예정인 외해 해조류 대량양식시설의 구조물 설치 및 공간 배치를 위한 기초자료로 대상해 역의 지형구조 및 해수순환특성을 조사하였다. 관측결과 기장군 해역은 대체로 수심이 깊은 해역으로 해안에서 3-4 km 부근에서 30 m 이상의 비교적 깊은 수심을 보였다. 외해 해조류 대량양식시설의 적지선정을 위한 기초자료로 해황조건(조위, 조류)을 검토하기 위하여 수치모형 실험을 이용한 주변해역의 해수훈환 특성을 검토하였다. 대상해역은 한반도의 동해남부에 위치하여 외해역으로 갈수록 수심 이 급격히 증가하는 양상을 보이며, 특히 지형적 특성으로 인하여 바람의 내습이 큰 지역이나 본 연구에서는 외해구조물의 특성상 파랑 에 대한 구조물의 내파특성에 대한 검토는 실시하지 않았다. 대상해역은 서해나 남해안에 비하여 비교적 수심이 깊은 해역으로 대량양 식 시설 적정 수심역은 외해 양식시설의 특성 및 구조물 설치상의 특성등을 고려하여 적정 수심역을 15m~40m 선정하였다. 수치모형 실험 결과 해수유동은 창조시 남서방향으로 약 0.4 m/s 의 유속분포를 보였으며, 낙조시도 이와 반대방향으로 유사한 유속분포를 보였 다.
        4,000원
        433.
        2011.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        오징어 젓갈과 한치 젓갈의 차이를 질량분석기를 기반으로 한 전자코를 이용하여 분석한 결과 두 시료의 mass spectrum은 뚜렷한 차이를 보였다. 판별함수분석을 통해 휘발성분의 패턴을 분석한 결과 오징어 젓갈과 한치 젓갈이 뚜렷이 구분되었으며 젓갈의 양념을 제거한 후 분석하였을 때 구분이 더 잘되었다. 결과적으로 전자코를 이용하여 유사 식품 간의 차이를 충분히 구분 가능하였으며 이러한 결과는 추후 젓갈뿐 아니라 다양한 방면에 적용 가능할 것으로 보여 EMA 식품을 선별하는 데에도 도움이 될 것으로 기대된다.
        4,000원
        434.
        2011.05 구독 인증기관·개인회원 무료
        Two species entomopathogenic fungi most widely used and valued in traditional Asian medical practice are Ophiocordyceps sinensis (formely Cordyceps sinensis) and Cordyceps militaris. Although O. sinensis may be the more famous and expensive fungus, it is also comparatively rare and cannot be grown or made to fruit readily in culture whereas C. militaris occurs worldwide, can be easily cultured, and is the easist of all Cordyceps species to fruit in culture. There is a well establihed cottage industry in Korea to produce C. militaris as a dietary supplement or even as a culinary ingredient used to promote improved health. Most of the Korean farmers raising C. militaris obtain fruiting bodies from silkworms that are injected with suspensions of hyphal bodies grown in liquid cultures. This study seeks to facilitate and to simplify the injection process used to produced this fungus by finding a simple cullture medium on which abundant supplies of the Lecanicillium conodial state of C. militaris are produced and can be used with simplified injection protocols involving spraying or dipping in conidial suspensions than the more material- and labor- intensive injection protocol. The studies to be repored include quantitative tests of conodial yields on varying carbon sources, varying nitrogen sources, and attempted to optimize the carbon/nitrogen ratio and pH of the medium for conidial production.
        435.
        2011.05 구독 인증기관·개인회원 무료
        This study was conducted to examine the potential of surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) to screen Tetranychus urticae resistance to pyridaben and dicofol. T. urticae is one of the most important pests in greenhouse and orchard, and huge expense is needed to control because of its strong resistance to acaricides. Consequently speedy and accurate monitoring of acaricidal resistance is the key factor of IPM for T. urticae. SELDI-TOF MS is a novel approach to biomarker discovery that combines two powerful techniques: chromatography and mass spectrometry. It can provide a rapid protein expression profile of acaricidal sensitive and resistant T. urticae. In this study we had different protein and peptide patterns between sensitive and resistant strains to pyridaben and dicofol. In the future this results could be a useful data to develop a good monitoring tool of site and host specific mite resistance to various acaricides.
        437.
        2011.05 구독 인증기관·개인회원 무료
        In this study, we reared box tree pyralid, Glyphodes perspectalis, with artificial diet and identified sex pheromone. Insect F-II and leaf of box tree were used to make artificial diet. Box tree pyralid, Glyphodes perspectalis, is the most serious pest of box tree in Korea, and was recently introduced into Europe. The pheromone components of this moth have been identified as (Z)-11-hexadecenal (Z11-16:Ald), (E)-11-hexadecenal (E11-16:Ald), and (Z)-11-hexadecenol (Z-11- 16:OH) in Japan. In this study, we identified pheromone components of this species by using GC and GC-MS. Three same components, such as (Z)-11- hexadecenal (Z11-16:Ald), (E)-11-hexdecenal (E11-16:Ald), and (Z)-11-hexadecenol (Z-11-16:OH) were also indentified in Korean population, but there was a little difference in ratios. The ratios of these three compounds of Japanese population and Korean population were 5:1.25:1, and 5:0.96:0.2, respectively. The ratios of Z and E-11-hexadecenal were similar, but the ratio of (Z)-11-hexadecenol was lower compared to Japanese population. In field bioassay, (Z)-11-hexadecenal or (E)-11-hexadecenal alone was not attractive to males, but the mixture of Z11-16:Ald and E11-16:Ald was attractive to males. The most effective ratios of Z11-16:Ald and E11-16:Ald was 5:1. Other ratios such as 1:1 and 1:5 (Z:E) was not attractive to males. The attractiveness of Z:11-16:OH will be tested in near future.