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        검색결과 24

        1.
        2018.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Microalgae produce not only lipids for biodiesel production but also valuable biochemicals which are often accumulated under cellular stress mediated by certain chemicals. While the microcarriers for the application of drug delivery systems for animal cells are widely studied, their applications into microalgal research or biorefinery are rarely investigated. Here we develope dual-functional magnetic microcapsules which work not only as flocculants for microalgal harvesting but also potentially as microcarriers for the controlled release of target chemicals stimulating microalgae to enhance the accumulation of valuable chemicals. Magnetic microcapsules are synthesized by layer-by-layer(LbL) coating of PSS-PDDA on Fe3O4 nanoparticle-embedded CaCO3 microparticles followed by removing CaCO3 sacrificial templates. The positively charged magnetic microcapsules flocculate microalgae by electrostatic interaction which are sequentially collected by the magnetophoretic separation. The microcapsules with a polycationic outer layer provide efficient binding sites for negatively charged microalgae and by that means are further utilized as a chemical-delivery and flocculation system for microalgal research and biorefineries.
        4,000원
        4.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 질병 데이터를 활용한 사망률의 지도화에서 지역별 사망률의 변동성을 안정화할 수 있도록 하는 베이지언 기법을 적용하고, 기본적으로 활용되고 있는 SMR (Standardized mortality ratio)과 그 결과를 비교하였다. 우리나라 전국의 시군구 단위의 전립선암 사망자 수 데이터에 표준화와 베이지언 기법을 적용하고, 산출된 사망률을 지도화하여 기존에 없던 우리나라의 전립선암 사망률 지도를 질병 지도의 예시 자료로 작성하였다. 분석 결과, Bayesian 모델링 기법을 통해 계산된 위험비는 기존 SMR에 비해 좀 더 수렴된 형태의 안정적인 통계량을 가지는 것을 알 수 있었다. 국지적 Bayesian 기법은 이웃 지역들의 정보만을 반영하여 위험비를 평활화하기 때문에 본 연구에서 사용된 전역적 기법들과 비교할 때 평활화의 강도가 크지 않았다.
        4,200원
        5.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A new process for the synthesis of polyphenylcarbosilane (PPCS) via thermal rearrangement of polymethylphenylsilane (PMPS) in supercritical cyclohexane was proposed and investigated at reaction temperatures of 380-420℃, reaction times of 1-2 h, and a pressure of 15 MPa. The structure, molecular weight, and molecular weight distribution of the product were characterized by FT-IR, Si-NMR, and GPC. The ceramic yield was also measured by TGA analysis. High-quality PPCS with high molecular weight and ceramic yield can be synthesized via a supercritical process. Furthermore, this process, when compared to the conventional method, tends to moderate the reaction conditions such as reaction temperature and time. It is concluded that thermal rearrangement in supercritical fluid is an efficient and viable process in terms of the resulting yield, efficiency, and reaction time compared with those of the conventional PCS production process.
        4,000원
        6.
        2010.03 구독 인증기관 무료, 개인회원 유료
        Periodontal disease is a major oral disorder and comprises a group of infections that lead to inflammation of the gingiva and the destruction of periodontal tissues. PPARy plays an important role in the regulation of several metabolic pathways and has recently been implicated in inflammatory response pathways. However, its effects on periodontal inflammation have yet to be clarified. In our current study, we evaluated the anti-inflammatory effects of PPARy on periodontal disease. Human gingival fibroblasts (HGFs) treated with lipopolysaccharide (LPS) showed high levels of intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), matrix metalloproteinase-2 (MMP-2), and -9 (MMP-9). Moreover, these cells also showed upregulated activities for extracellular signal regulated kinase (ERK1/2), inducible nitric oxide synthase (iNOS) and cyclooxygnase-2. However, cells treated with Ad/PPARy and rosiglitazone in same culture system showed reduced ICAM-1, VCAM-1, MMP-2, -9 and COX-2. Finally, the anti-inflammatory effects of PPARy appear to be mediated via the suppression of the ERK1/2 pathway and consequent inhibition of NF-kB translocation. Our present findings thus suggest that PPARy indeed has a pivotal role in gingival inflammation and may be a putative molecular target for future therapeutic strategies to control chronic periodontal disease.
        4,000원
        9.
        2006.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the ability of human subjects to match a force in their quadriceps muscle during fatigue. Twenty subjects (mean age: 23.4 yrs, mean height: 167.8 cm, mean weight, 62.6 kg) were enrolled in the experiment. In the force-matching task, the quadriceps muscle generated 50% of the MVIC (maximum voluntary isometric contraction) torque under visual control and then without visual feedback. After inducing fatigue in the quadriceps muscle, the subjects were required to match 50% of the MVIC torque without visual feedback. The perceived magnitude of the force and force-matching errors were measured. 50% of the MVIC torque was perceived from 39.96 Nm in the pre-fatigue condition to 44.95 Nm in the post-fatigue condition. 50% of the MVIC torque-matching errors increased significantly from .55% in the pre-fatigue condition to 9.6% in the post-fatigue condition (p<.001). in addition, there were significantly more force-matching errors in women than in men (p<.01). In conclusion muscle fatigue can interfere with a subject's ability to match a force. This suggests that muscle fatigue may contributes to the sensitization of the proprioception.
        4,000원
        11.
        2003.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 초기 편마비 환자의 손목에서 표면근전도 분석을 통해 근수축 개시 및 종료의 특성들을 알아보고, 임상적인 치료방법의 기초를 제안하고자 실시하였다. 연구대상자는 원주기독병원에 뇌졸중으로 입원한 환자 중 발병 후 3개월 미만인 13명과 원주시에 거주하는 대조군 7명이었다. 근수축 개시 및 종료의 지연은 표면근전도를 이용하여 손목굽힘근과 손목펴짐근에서 손목관절의 굽힘과 폄동작 시 3초의 근전도 신호음에 따라 가장 빠르고 강하게 최대 등척성 수축과 이
        4,000원
        14.
        1997.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        5,400원
        15.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        4,800원
        16.
        2011.03 KCI 등재 서비스 종료(열람 제한)
        Embryonic stem (ES) cells can self-renew maintaining the undifferentiated state. Self renewal requires many factors such as Oct4, Sox2, FoxD3, and Nanog. NF- is a transcription factor involved in many biological activities. Expression and activity of NF- increase upon differentiation of ES cells. Reportedly, Nanog protein directly binds to NF- protein and inhibits its activity in ES cells. Here, we found a potential binding site of NF- in the human Nanog promoter and postulated that NF- protein may regulate expression of the Nanog gene. We used human embryonic carcinoma (EC) cells as a model system of ES cells and confirmed decrease of Nanog and increase of NF- upon differentiation induced by retinoic acid. Although deletion analysis on the DNA fragment including NF- binding site suggested involvement of NF- in the negative regulation of the promoter, site-directed mutation of NF- binding site had no effect on the Nanog promoter activity. Furthermore, no direct association of NF- with the Nanog promoter was detected during differentiation. Therefore, we conclude that NF- protein may not be involved in transcriptional regulation of Nanog gene expression in EC cells and possibly in ES cells.
        17.
        2005.12 KCI 등재 서비스 종료(열람 제한)
        Scrophularia takesimensis Nakai called "Sum-Hyun-Sam", growing about 1m in high is a perennial plant of Scrophulariaceae. Because the number of these species is very limited in the world, the Ministry of Environment has appointed S. takesimensis as a preserved plant. The Korea Forest Service also protects it strictly by the law since S. takesimensis is an out-of-the-way plant and possible to be exterminated soon in Korea. Investigation for distribution and ecological characteristics of the habitat for S. takesimensis was carried out in Ulleung-do Island. S. takesimensis has a tendency to emerged with Calystegia soldanella Roem. et Schultb. and Artemisia japonica subsp. littoricola Kitam. C. soldanella community were developed on the dry and well-lighted as east or north facing conditions. A. japonica subsp. littoricola community have tendency to developed on the properly lighted as west or north facing and well maintained soil or air humidity. C. soldanella community were developed on the sandy gravel or gravel and grew with Farfugium japonicum, (L.) Kitam., Lonicera japonica Thunb., and Peucedanum japonicum Thunb.. A. japonica subsp. littoricola communities were emerged on the rock beds or pile of rocks and grew with Sedum oryzifolium Makino, Sedum takesimense Nakai, and Spergularia marina (L.) Griseb..
        18.
        2005.03 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to provide the basic data for an identifying system for Iris species distributed in Korean market from complete analysing of genetic relationship between three native Iris species and one cultivar bred from the native Iris plant. RAPD analysis of genetic relationship among 4 Irises was possible. According to the RAPD analysis, they were divided into two groups. Among 4 Irises used in this study, Iris laevigata 'Veriegata', Iris laevigata and Iris setosa were classified into the same group since they had many similarities even though the habitat of Iris laevigata in Korean peninsular is restricted mainly in the south and Iris setosa is naturally inhabited in the northern part of Kangwondo. The value for the dissimilarity index of Iris laevigata and Iris laevigata ‘Veriegata’ was 6.757. The value for the dissimilarity index of Iris laevigata and Iris dichotoma was 95.000, so that they were genetically the farthest among them since the genetic relationship between two species are separated far if the value of the dissimilarity index is close to 100.
        19.
        2003.11 KCI 등재 서비스 종료(열람 제한)
        Hibiscus hamabo, called "Hwang-geun", growing about 3m in height is a deciduous shrub or subtree of Malvaceae. Because the number of these species is very limited in the world, the Ministry of Environment has designated H. hamabo as a preserved plant. The Korea Forest Service also protects it strictly by law since H. hamabo is an out-of-the-way plant and possibly may be exterminated soon in Korea. Investigation for distribution and ecological characteristics of the habitat for H. hamabo was carried out on Soan Island. Two wild H. hamabo were found at the forest edge (34。11‘35.4“N, 126。38'55.9"E) along the sea coast located in the southern part of Soan Island and this was the first report in the Korean academic world. These two wild H. hamabos were growing in a naturally inhibited area. The diameters at the base were 12cm and 15cm. The Tree heights were 150cm and 210cm and the number of branches of each wild H. hamabo was 4 and 7. However, the present condition of these plants was not good. Environmental conditions of the naturally inhibited area of H. hamabo were very mild because it is located at the edge of the forest and is always sunny during the daytime since the slope of the inhibited area is facing South. The ground drained very well since the soil was made of gravels and sand. Because the percent of vegetation of the subtree layer where H. hamabo was growing was 40%, the cover degree and sociability of Ilex crenata trees and Eurya japonica were found to be high. In the naturally inhibited area of H. hamabo, a dominant value of Rubus parvifolius in the lower part of the herb layer was very high and many plants in Compositae, such as Artemisia princeps var. orientalis and Erigeron annuus, were also present. A dominant value of liana, such as Vitis thunbergii var. sinuata, Rosa multiflora, Clematis terniflora and Hedera rhombea, and Gramineae plants that rhizomes were well developed and aggressively propagated, such as Miscanthus sinensis var. purpurascens, Phragmites communis, Spodiopogon cotulifer and Oplismenus undulatifolius which were surveyed as high, too. These results imply that H. hamabo might be exterminated soon through a natural selection if the proper management of the naturally inhibited area of H. hamabo is not conducted continually.
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