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        검색결과 988

        641.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        원자전달 라디칼 중합(ATRP)에 의해 poly(vinyl chloride) (PVC) 주사슬과 poly(styrene sulfonic acid) (PSSA) 곁사슬로 되어있는 양쪽성 PVC-g-PSSA 가지형 공중합체를 합성하였다. 합성된 고분자 전해질막을 10 wt% AgNO3 수용액에 담가 은이온으로 이온교환을 하였으며, 환원제를 통하여 은 나노입자를 성장시켰다. UV분광학과 XRD 분석을 통해 은 나노입자 성장을 확인하였다. 투과전자현미경(TEM) 분석결과 NaBH4를 사용하였을 때 10~20 nm 크기의 은 나노입자를 얻는데 가장 효과적임을 알 수 있었다. 또한 은 나노입자의 성장은 환원제의 농도와 환원 시간에 크게 영향을 받았다.
        4,000원
        642.
        2010.12 구독 인증기관 무료, 개인회원 유료
        Angelica decursiva has been used in Korean traditional medicine as an antitussive, an analgesic, an antipyretic and a cough remedy. However, its anti-cancer properties have not yet been well defined. In our current study, we report the cytotoxic activity and the mechanism of cell death induced by ethanol extracts of Angelica decursiva (EEAD) against the human oral cancer cell line, KB. Treatment of KB cells with EEAD induced apoptotic cell death in both a dose- and time-dependent manner as determined by MTT assay and DNA fragmentation. However, no cytotoxic effects of EEAD against human normal oral keratinocytes (HNOK) were evident. By western blot analysis, we found that apoptosis in KB cells is associated with a decrease in procaspase-7 and -9. In addition, the activation of caspase-7 was detectable in living KB cells by fluorescence microscopy. These results suggest that EEAD exhibits anti-cancer activity in KB cells via apoptosis and thus has potential as an anticancer agent in future drug development strategies.
        4,000원
        643.
        2010.12 구독 인증기관 무료, 개인회원 유료
        Angelica decursiva has been used in Korean traditional medicine as an antitussive, an analgesic, an antipyretic and a cough remedy. However, the anti-cancer properties of Angelica decursiva have not yet been well defined. In our current study the cytotoxic activity of ethanol extracts of Angelica decursiva root (EEAD) and the mechanism of cell death exhibited by EEAD were examined in FaDu human head and neck squamous cell carcinoma cells. The cytotoxic effects of EEAD upon the growth of FaDu cells were examined with an MTT assay. In addition, the mechanism of cell death induced by EEAD was evaluated by DNA fragmentation analysis, immunoblotting and caspase activation measurements. EEAD induced apoptotic cell death in FaDu cells in a concentration- and time-dependent manner, as determined by MTT assay and DNA fragmentation analysis. Furthermore, the proteolytic processing of caspase-3, -7 and -9 was increased by EEAD treatment of FaDu cells. In addition, the activation of caspase-3 and -7 was detected in living FaDu cells by fluorescence microscopy. These results suggest that EEAD can induce apoptosis and suppress cell growth in cancer cells and may have utility as a future anticancer therapy.
        4,000원
        644.
        2010.12 구독 인증기관 무료, 개인회원 유료
        To evaluate the biohazard properties of an extremely low frequency electromagnetic field (ELF-EMF), we explored the physical properties of the ELF-EMF that generates the electric current induction in the secondary coil from the chamber of a primary solenoid coil. We subsequently explored the biological effects of a strong alternating electromagnetic field (EMF), ranging from 730-960 Gauss, on the mouse testis. Mice were exposed to an alternating EMF field induced by a rectangular electric current at 1, 7, 20, 40, and 80 Hertz, for 1, 3, 5, and 7 hours. The mouse testes were examined for proliferative activity and apoptosis using the in situ terminal deoxynucleotidyl transferase (TdT) method and by immunostaining of proliferating cell nuclear antigen (PCNA), respectively. We found that the electric currentm induction increased in the 6-8 Hertz range, and that exposure to an ELF-EMF induced the apoptosis of mouse spermatocytes. In situ TdT staining was found to be most prominent in 7 Hertz group, and gradually reduced in the 20, 40, and 80 Hertz groups. These data suggest that a strong EMF can induce reproductive cell death within a short time, and the harmful effects of the EMF are maximal at low frequency alternating EMFs.
        4,000원
        645.
        2010.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        한국원자력연구원 내에 위치하는 방사성폐기물지하처분연구시설의 터널 내 벽면의 지반변위 및 온도 변화를 실시간으로 감시할 수 있는 시스템을 구축하였다. 이 시스템은 광섬유케이블(Optical Fiber Cable)의 Brillouin 산란현상을 이용하는 분포개념의 온도 및 변형율 측정기법(Distributed Temperatureand Strain Sensor: DTSS)을 적용하는 기술이다. 2년여 동안 감시한 결과 터널 벽면 쇼크리트 표면에서 균열 등과 관련한 뚜렷한 벽면 변위 징후는 발견되지 않았다. 다만, 시간이 경과함에 따라 터널 내에서 지 하수 누출 지점을 중심으로 벽면에서 변형의 누적 크기가 증대되어가는 경향을 보이나 그 크기는 미약하 고 완만하게 진행함을 확인하였다. 계속적인 지하수에 의한 포화-습윤-건조 등의 현상이 반복되는 구간이 나 포화상태에 있는 구간은 점진적으로 영향이 커질 것으로 예상된다. 광섬유센서케이블을 이용한 분포 개념의 측정 및 분석기술은 구조물의 특성에 따라 선택적ㆍ탄력적 적용이 가능하다. 변형률의 계측 범위 는 20 ∼28,000 크기까지 변위 계측이 가능하다. 변형률의 해상도는 0.01mm로서 최소 매 1m 간격, 온도는 0.01℃ 해상도를 가지고 최소 0.5m 간격으로 감시가 가능하다. 기존의 특정지점 계측방법(Point Sensing)과는 확연하게 차별된다. 현재까지 운영한 결과 본 감시시스템은 방사성폐기물 처분시설 등 공 동과 사면의 장기감시시스템으로 적용 가능성을 확인하였다.
        4,000원
        646.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to investigate the effects of closed and open kinetic chain exercise for increasing knee joint function on the knee position sense in the normal adults. Thirty normal adults(male 15, female 15; mean age: 22.13±2.58 years) were participated in this study into two groups, each with 15 people. The group I was trained that closed kinetic chain exercise on the knee joint and the group II was trained that open kinetic chain exercise on the knee joint. Exercise programs performed for 4 weeks, 3 times a week were using Shuttle 2000-1 closed kinetic chain exercise and Knee Extensor open kinetic chain exercise(HUR, Filand). The results of this study were as follows: 1) There were statistically significant decreasing of measuring error degree in 0-20。were found between before and after training in closed kinetic chain exercise(p<.05). 2) There were statistically significant decreasing of measuring error degree in 21-40。were found between before and after training in closed kinetic chain exercise(p<.05). 3) There were statistically significant decreasing of measuring error degree in 41-60。were found between before and after training in closed kinetic chain exercise(p<.05). 4) There were statistically significant decreasing of measuring error degree in 0- 20。were found between before and after training in open kinetic chain exercise(p<.05). 5) There were statistically significant decreasing of measuring error degree in 21-40。were found between before and after training in open kinetic chain exercise(p<.05). 6) There were statistically significant decreasing of measuring error degree in 41- 60。were found between before and after training in open kinetic chain exercise(p<.05). In conclusion, these results suggest that closed and open kinetic chain exercise has increased in the knee joint proprioception between before and after training. Especially, closed kinetic chain exercise could be more useful intervention than open kinetic chain exercise for increasing proprioceptive sense.
        4,000원
        647.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine the difference of the pinch strength according to testing posture(standing and sitting) and elbow flexion degree(0。, 45。, 90。and 135。). Forty normal young adults(male: 20, female: 20, mean age: 22.68±2.91 years) participated in this study. The methods of this study were categorized as follows: 1) One set of measurement was performed on four elbow flexion degrees(0。, 45。, 90。and 135。) in two testing postures(standing and sitting) and all subjects were measured for 3 sets testing procedures in every experimental sessions. 2) Pinch strength in various elbow flexion degree was measured after 2 min rest time, and then each test set was repeatedly performed with 5 min rest time to prevent fatigue of muscles involved in the elbow joint. The result was obtained as follow: 1) In standing posture, there was statistically significant difference at 0。and 45。, 0。and 90。, 0。and 135。, 45。and 90。, 45。and 135。, 90。and 135。. 2) In sitting posture, there was statistically significant difference at 0。and 45。, 0。and 90。, 0。and 135。, 45。and 90。, 45。and 135。, 90。and 135。. 3) Statistically, there was no significant difference between standing and sitting posture in same elbow flexion degree, however pinch strength in standing posture was higher than sitting posture.
        4,000원
        648.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The majority of strokes are caused by ischemia and result in brain tissue damage, leading to problems of the central nervous system including hemiparesis, dysfunction of language and consciousness, and dysfunction of perception. The purpose of this study was to investigate the effects of Poly(ADP-ribose) polymerase(PARP) on necrosis in neuronal cells that have undergone needle electrode electrical stimulation(NEES) prior to induction of ischemia. Ischemia was induced in male SD rats(body weight 300g) by occlusion of the common carotid artery for 5 min, after which the blood was reperfused. After induction of brain ischemia, NEES was applied to Zusanli(ST 36), at 12, 24 and 48 hours. Protein expression was investigated using immuno-reactive cells, which react to PARP antibodies in cerebral nerve cells, and Western blotting. The results were as follows: In the cerebral cortex, the number of PARP reactive cells after 24 hours significantly decreased(p<.05) in the NEES group compared to the GI group. PARP expression after 24 hours significantly decreased(p<.05) in the NEES group compared to the GI group. As a result, NEES showed the greatest effect on necrosis- related PARP immuno-reactive cells 24 hours after ischemia, indicating necrosis inhibition, blocking of neural cell death, and protection of neural cells. Based on the results of this study, NEES can be an effective method of treating dysfunction and improving function of neuronal cells in brain damage caused by ischemia.
        4,000원
        650.
        2010.10 구독 인증기관·개인회원 무료
        Cuticular hydrocarbons (CHCs) were analyzed using GC and GC-MS, and compared with developmental stages of the Lycorma delicatula. Total Carbon numbers on all developmental stages are 21-36, and composition numbers are 51. On the whole, Carbon numbers increased as passed times on developmental stages. Except for eggs, Lycorma delicatula consisted of n-heptacosane on almost all developmental stages, and followed by n-nonacosane. Eggs, however, consisted of 9-; 11-; 13- methylheptacosane. From the above results, CHCs on developmental stages of the Lycorma delicatula consisted of n-alkane with saturated hydrocarbons (36%), followed mono- (34%) or di- (21%) methylalkanes. Above this, CHCs consisted of tri- methylalkanes (3.9%) and olefines (2.3%) that have double bond. The major constituents of CHCs on the developmental stages of Lycorma delicatula is differently proportioned, but hardly showed the difference in their composition.
        651.
        2010.09 구독 인증기관 무료, 개인회원 유료
        The effects of chitosan upon the experimentally induced differentiation of MDPC-23 cells, derived from mouse dental papilla cells, were investigated by RT-PCR, observations of cell morphology and Alizaline red-S staining. Chitosan was found to significantly increase and accelerate the expression of ALP mRNA but decrease the ColI transcript levels, as compared with the control, in a time-dependent manner during the differentiation of MDPC-23 cells. Chitosan also significantly downregulated ON mRNA expression and accelerated mineralization in differentiating MDPC-23 cells. These results suggest that chitosan facilitates odontoblast differentiation and mineralization and may have potential clinical applications as a dentin regeneration material.
        4,000원
        652.
        2010.06 KCI 등재 구독 인증기관·개인회원 무료
        This study was carried out to investigate characteristic pattern of fruiting body of Ganoderma lucidum and their antioxidant activity. Mycelia of all strains were firstly inoculated into potato dextrose agar(PDA) and then transfered to a media of saw dust which contained 20% rice bran. These mycelia of saw dust were then inoculated into oak tree in polyethylene bags which has been sterilized for 8h at 120℃. The polyethylene bags were sent to a growth room for growth of fruit bodies. Antioxidant activities of each fruiting body were examined by using DPPH(α,α-diphenyl-β-picrylhydrazyl).
        653.
        2010.05 구독 인증기관·개인회원 무료
        Field survey was conducted to determine the differences of spider community between traditional farming and environmental friendly farming at 17 localities, Korea in 2008. In guild structure, The occupancy rate of pest group, general group and natural enemy group was 37.3%, 41.0% and 21.6% respectively in environmental friendly farming, and 36.9%, 35.6% and 27.5% respectively in traditional farming. Among natural enemy group, parasitoids and predators were 15.8% and 84.2% respectively in environmental friendly farming, and 28.1% and 71.9% respectively in traditional farming. Among natural enemy group, rice field spiders were 74.4% and 62.2% in environmental friendly farming and traditional farming respectively. Among predators, rice field spiders were 86.7% in environmental friendly farming and 84.9% in traditional farming. Rice field spider community comprises 28 species of 24 genera belonging to 10 families and 30 species of 24 genera belonging to 10 families in environmental friendly farming and traditional farming respectively. Dominant families were Lycosidae, Linyphiidae and Tetragnathidae and dominant species were Pirata subpiraticus, Ummeliata insecticeps, Tetragnatha maxillosa, Gnathonarium dentatum and Packygnatha clercki in both agricultural practices. The ratio of hunting spiders and webbing spiders was similar between agricultural practices.
        654.
        2010.05 구독 인증기관·개인회원 무료
        In an effort to gain a better understanding of the nature of the population genetic structure of the pest insect, Spodoptera litura (Lepidoptera: Noctuidae), tobacco cutworms were collected from six Korean and five Chinese localities and their mitochondrial A+T-rich region and nuclear internal transcribed spacer 2 (ITS2) regions were cloned and sequenced. A total of 106 A+T-rich region haplotypes and 92 ITS2 sequence types were obtained from 158 individuals. Compared to the preliminary mitochondrial COI gene sequence data that provided all identical sequence types in all samples, the A+T-rich region and nuclear ITS2 are highly variable. Overall, a low level of genetic fixation in the A+T-rich region (FST = 0 ~ 0.02965) and nuclear ITS2 (FST = 0 ~ 0.34491), and no discernable isolated population was noted to exist among most S. litura populations. The presence of a majority of within-population variations, rather than variations among populations or between China and Korea, indicates that the S. litura populations are composed of heterogeneous individuals. The fixation index at hierarchical level of among regions shows no significance, suggesting that the S. litura populations in both Korea and China are profoundly interrelated with one another. This finding is in accord with the current knowledge that S. litura has sufficient flight capacity for dispersal.
        655.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate the effects of Needle Electrode Electrical Stimulation(NEES) on ischemia-induced cere˗ brovascular accidents. After obstruction and reperfusion of arteries in white mice, the amounts of necrosis and inflammation related sub˗ stances Bax, IL-6, Caspase-3, and COX-2 were measured in neurons of the fore-brain. The following results were obtained. This study used 21 male specific pathogen free(SPF) SD rats, 8 weeks of age and approximately 300g in weight. Each exposed artery was completely occluded with non-absorbent suture thread and kept in that state for 5 minutes. The sutures were then removed to allow reperfusion of blood. Test group is control group(common carotid artery occlusion models), a GI(underwent common carotid artery occlusion), and NEES(underwent NEES after artery occlusion). The GI and NEES groups were given 12, 24, or 48 hours of reperfusion before NEES. NEES device(PG6, ITO, Japan, 9V, current, 2Hz) was used to stimulate the bilateral acupoint ST36 of the SD rats for 30 minutes while they were sedated with 3% isoflurane. An immuno-his˗ tochemistry test was done on the forebrains of the GI induced rats. Both Bax and Caspase-3 immuno-reactive cells, related to apoptosis, were greater in the GI than the NEES group. Cox-2 and IL-6 immuno-reactive cells, related to inflammation, were greater in the GI and NEES groups than the control group. We can expect that applying NEES after ischemic CVA is effective for preventing brain cells from being destroyed. And we can conclude NEES should be applyed on early stage of ischemic CVA.
        4,000원
        656.
        2009.12 구독 인증기관 무료, 개인회원 유료
        There have been significant changes to family values and the types of families have diversi-fied. This phenomenon gave way to the rise of the lower fertility and aging society, and could also cause disorganization or crisis of family in the future. It has now become necessary to build family-friendly values through the new education envi-ronment, Web 2.0. Social Network Service (SNS), the main idea of this study, represents one type of the new environment. It is a vital and well-matched concept with family-friendly val-ues. The paradigm shift in education has features such as interaction, relationship and com-munication. The purpose of this study was to suggest feasibility of Social Network Service for forming family-friendly values. To verify the feasibility, four family websites in Korea were examined with the research method of SWOT Analysis. To find strategies, SWOT factors were identified as follows; 1) Strength factors of Social Network Service for family-friendly values formation: free ser-vice, diverse functions, and global interactivity through language service. 2) Weakness factors: unstable, virtual disorder resulting from too many functions, and lack of user directedness. 3) Opportunity factors: increasing needs of family value education and improvement to mul-ticultural society. 4) Threat factors: digital literacy divide between old and new generation and decreasing time to communicate with family. In this study, the following seven strategies were extracted through SWOT analysis: 1) Practice educational paradigm shift: Web 2.0 2) Change educational settings in multicultural society 3) Challenge media convergence 4) Represent ability of ubiquitous learning 5) Promote interactivity across all age groups, taking into account life cycle 6) Present user-directed interfaces 7) Conduct instructional contents or curriculum with blended learning at K-12 Keywords: Family friendly values, Web 2.0, Learning 2.0, SWOT Analysis
        4,600원
        659.
        2009.10 구독 인증기관·개인회원 무료
        The Nilaparvata lugesn(BPH) and Laodelphax striatellus(SBPH) are major insect pests of rice in Korea. These BPHs migrate from China to Korea, but we have not exactly known about the route of long-distance migration of them. Molecular markers including microsatellite will be critical to asses gene flow in relation to geographical distance. In our work several microsatellite markers were developed for basic population genetic analysis of BPH and SBPH. Among each 21 microsatellite markers in BPH and SBPH, we could select 6 markers for BPH and 2 markers for SBPH as putative markers for analysis of population genetics. Others are further investigated for the possibility as markers. Development of polymorphic microsatellite loci are final stage of our work. But for good microsatellite markers to population genetics, we should do more experiments. Our work for development of microsatellites should facilitate the study of future population genetics of BPH and SBPH, and eventually elucidate the route of BPH and SBPH migration to Korea.
        660.
        2009.10 구독 인증기관·개인회원 무료
        Ant species were reported to have specific vertical distribution in high mountains in Korea. The vertical distribution was recognized in Hanla mountain being highest in South Korea using pitfall traps in 2006. This phenomena suggests that temperature may be a main factor for distribution of ant species, since 0.5~0.6℃ of temperature decrease per each 100 m of altitude. The present study was carried out to test this hypothesis. Ant communities were surveyed using pitfall traps (ten traps per each site) at 234 sites, which included 9 high mountains in South Korea. The vertical distribution of ant species were found in all the high mountains. Abundance data (probability of occurrence, %) of seventeen abundant ant species which occurred at more than 10% of the study sites were analyzed using multiples regression analysis with four independent factors such as temperature, precipitation, light intensity, and NDVI. As results of the regression analysis, temperature was most important in determining the abundance in 11 of 17 species. Light intensity was most important in 3 species, and precipitation in 1 species. In the 11 species being highly dependent on temperature, determination index (R2) of regression model with one factor of temperature was approximately 90% of determination index of the regression model with all four factors. On the base of dependence on temperature and of ecological characteristics (ground foraging), six species such as Paratrechina flavipes, Myrmica kotokui, Pachycondyla javana, Pristomyrmex pungens, Camponotus atrox, and Crematogaster osakensis were selected as bioindicator for global warming. In the bioindicator ant species, M. kotokui and C. atrox were predicted to decline in abundance and distribution in Korean peninsula as temperature increases, whereas other four species including P. flavipes, P. javana, P. pungens, C. osakensis were predicted to increase. Temperature-Distribution models were established in four most temperature-responsive species including P. flavipes, P. javana, P. pungens, and M. kotokui, and distribution maps of the species were made from the model. Reversely, temperature was estimated from ant data of five bioindicator species using regression model, of which R2 is 0.66.