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        검색결과 25

        5.
        2018.12 구독 인증기관 무료, 개인회원 유료
        Exosomes are Nano-sized lipid vesicles secreted from mammalian cells containing diverse cellular materials such as proteins, lipids, and nucleotides. Multiple lines of evidence indicate that in saliva, exosomes and their contents such as microRNAs (miRNAs) mediate numerous cellular responses upon delivery to recipient cells. The objective of this study was to characterize the different expression profile of exosomal miRNAs in saliva samples, periodically isolated from a single periodontitis patient. Unstimulated saliva was collected from a single patient over time periods for managing periodontitis. MicroRNAs extracted from each phase were investigated for the expression of exosomal miRNAs. Salivary exosomal miRNAs were analyzed using Affymetrix miRNA arrays and prediction of target genes and pathways for its different expression performed using DIANA-mirPath, a web-based, computational tool. Following the delivery of miRNA mimics (hsa-miR-4487, -4532, and -7108-5p) into human gingival fibroblasts, the expression of pro-inflammatory cytokines and activation of the MAPK pathway were evaluated through RT-PCR and western blotting. In each phase, 13 and 43 miRNAs were found to be differently expressed (|FC| ≥ 2). Among these, hsa-miR-4487 (|FC|=9.292005) and hasmiR- 4532 (|FC|=18.322697) were highly up-regulated in the clinically severe phase, whereas hsa-miR-7108-5p (|FC|= 12.20601) was strongly up-regulated in the clinically mild phase. In addition, the overexpression of miRNA mimics in human gingival fibroblasts resulted in a significant induction of IL-6 mRNA expression and p38 phosphorylation. The findings of this study established alterations in salivary exosomal miRNAs which are dependent on the severity of periodontitis and may act as potential candidates for the treatment of oral inflammatory diseases.
        4,000원
        7.
        2017.10 구독 인증기관·개인회원 무료
        We have surveyed the current status of insect pollinator use for horticultural crops in 2016. The use rate and farmnumber of insect pollinators for 26 horticultural crops were 25.8% and 55,208, respectively. The colony number of insectpollinators used in this survey was 479,777, which include 344,690 for honeybees, 119,104 for bumblebees, 2,415 formason bees, 1,317 for flies, and 2,415 for the combination of bumblebees, honeybees, and mason bees. The use rateof insect pollinators was 59.4% for 11 vegetable crops and the colony number of insect pollinators used for 11 vegetablecrops was 449,287. The colony number of insect pollinators used for 15 fruit tree crops was 30,290, which include honeybees(66.3%), bumblebees (20.2%), mason bees (8.0%), flies (1.6%), and the combination (3.9%) of bumblebees, honeybees,and mason bees. Together, farms of 98% showed positive effect for the use of insect pollinators and most of farms (97.0%)planed for the continuous use of insect pollinators
        8.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, bulk nickel-carbon nanotube (CNT) nanocomposites are synthesized by a novel method which includes a combination of ultrasonication, electrical explosion of wire in liquid and spark plasma sintering. The mechanical characteristics of the bulk Ni-CNT composites synthesized with CNT contents of 0.7, 1, 3 and 5 wt.% are investigated. X-ray diffraction, optical microscopy and field emission scanning electron microscopy techniques are used to observe the different phases, morphologies and structures of the composite powders as well as the sintered samples. The obtained results reveal that the as-synthesized composite exhibits substantial enhancement in the microhardness and values more than 140 HV are observed. However an empirical reinforcement limit of 3 wt.% is determined for the CNT content, beyond which, there is no significant improvement in the mechanical properties.
        4,000원
        9.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, Fe-Cu-Ni-Mo-C low alloy steel powder is consolidated by spark plasma sintering (SPS) process. The internal structure and the surface fracture behavior are studied using field-emission scanning electron microscopy and optical microscopy techniques. The bulk samples are polished and etched in order to observe the internal structure. The sample sintered at 900oC with holding time of 10 minutes achieves nearly full density of 98.9% while the density of the as-received conventionally sintered product is 90.3%. The fracture microstructures indicate that the sample prepared at 900oC by the SPS process is hard to break out because of the presence of both grain boundaries and internal particle fractures. Moreover, the lamellar pearlite structure is also observed in this sample. The samples sintered at 1000 and 1100oC exhibit a large number of tiny particles and pores due to the melting of Cu and aggregation of the alloy elements during the SPS process. The highest hardness value of 296.52 HV is observed for the sample sintered at 900oC with holding time of 10 minutes.
        4,000원
        10.
        2016.04 구독 인증기관·개인회원 무료
        Distillers dried grain (DDG) and makgeolli spent grain (MSG) are agricultural by-product to produce alcoholic beverage. However, they are known to contain enough nutrients. Mealworm is a promising insect resource for an animal feed ingredient as well as alternative human food. With low cost, DDG and MSG were investigated as a feed ingredient for rearing high quality mealworms. DDG and MSG were mixed with wheat bran and compared to control feed (only wheat bran) for its effects on larval survivorship, larval weight, duration for larval development, pupation rate, and pupal weight. Adding DDG on wheat bran showed positive results for larval weight, duration for larval developmental period, and pupation rate. However, adding MSG made longer duration for larval development, but it also improved larval weight, pupal weight with more than 90% pupation rate. We confirmed that adding 30~50% of DDG or MSG to conventional wheat bran have a strong potential to replace the conventional wheat bran insect feed for quality insect production.
        11.
        2015.10 구독 인증기관·개인회원 무료
        Insect is an important player in the ecosystem as a prey for animals. Moreover, they are a valuable candidate food source for rearing animal. Tenebrio molitor (Coeloptera: Tenebrionidae) larvae are known as a good food source with high protein, unsaturated fatty acid, minerals. Therefore, it has strong potential to substitute the conventional meat consumption. To utilize T. molitor as a feed, the standard mass-rearing protocol is required. To make standard mass-rearing protocol, we tested different temperature(17.5, 20, 22.5, 25, 27.5 and 30°C) conditions for egg, larvae, pupae and adult T. molitor to identify the optimal rearing condition. Hatching was occurred within 15~32.5°C range. However, 17.5~27.5°C was required to get more than 70 % hatching rete. When the eggs were treated in 22.5~27.5°C, all eggs were hatched within 10 days. As larval development, shorter developmental period, higher pupation and eclosion rates were observed within 25~27.5°C temperature range. In addition, we compared the number of egg, oviposition duration and time required to start egg-laying. The minimum egg-laying(258.40±10.86) was observed at 17.5°C, but the maximum(749.10±7.45) was at 27.5°C. The maximum oviposition duration (137.00±12.73 day (mean±S.D.)) was achieved at 27.5°C, but the minimum (87.50±3.54 day (mean±S.D.)) was at 30°C. The time required to start egg-laying was less than 10 days at 17.5, 27.5, and 30°C. To consider all the factors, we concluded that the optimal temperature is 27.5 °C.
        12.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Streptomyces padanus IA70-5 has been shown to be a promising biological control agent for the suppression of pepper anthracnose. In this study, we assessed the potential use of strain IA70-5 as a biological control agent for Phytophthora blight caused by Phytophthora capsici. Strain S. padanus IA70-5 was found to inhibit the mycelial growth and zoosporangium formation of P. capsici causing Phytophthora blight on pepper plants. In experiments with hot pepper fruit, IA70-5 suppressed the progression of Phytophthora rot by over 90% in pre-inoculated treatments with culture suspension. In experiments with 60-day-old pepper plants, IA70-5 suppressed Phytophthora blight by over 90%. These results demonstrated the potential for S. padanus IA70-5 to provide a practical biological agent for the control of Phytophthora blight in the field.
        4,000원
        13.
        2013.04 구독 인증기관·개인회원 무료
        To substitute for bluebottle fly, Chrysomyia megacephala which is being used for pollinator in mango fruit, and improve the pollinating effect of mango fruit which is also being increased as high value added crop recently in Jeju island of korea, 2 kinds of pollinator were used in analyzing and surveying of foraging activities on mango fruit in Seogwipo province. This study was conducted using 3 species of pollinator, Apis mellifera, Bombus terrestris and Chrysomyia megacephala with 3 treatment in vinyl-house condition respectively. Species of mango fruit, Irwin, was used in this experiment. A number of foraging activity of Apis mellifera and Bombus terrestris in hive showed highest 11 AM, and showed normal foraging activity in high temperature condition(28℃). Pollinating ratio of Bombus terrestris was shown 100% and over 95% in case of Apis mellifera. This ratio suggest that the 2 species of insects is effective as pollinator on mango fruit compared with bluebottle fly. Daily pollinating activity of Apis mellifera and Bombus terrestris was shown peak in 11 AM, but showed even activity from 9 AM to 3 PM in case of Chrysomyia megacephala. The pollinating characteristics of 3 species depends on illuminance but temperature, especially in case of Bombus terrestris was more affected by change of illuminance. Visiting time of Bombus terrestris and Apis mellifera on this flower was shown 2.8 and 3.4 seconds respectively. But Chrysomyia megacephala showed longer 10 times with 32.5 seconds than other insects. This results suppose that Chrysomyia megacephala showed as resting behavior for almost time on the flower not foraging activity to pollinate.
        14.
        2013.04 구독 인증기관·개인회원 무료
        Worldwide studies on Apis cerana variation for biogeography and genetic diversity depended largely on a 86~93 bp-long mitochondrial non-coding region (internal spacer region) located between tRNALeu and COII (named as NC2), possibly due to higher variability among available markers. In order to incorporate the A. cerana occurring in South Korea into world extensive data, we also sequenced the NC2 from 118 A. cerana samples collected over nine Korean localities and 66 A. cerana samples over seven Asian localities, such as China, Vietnam, and Thailand. These data were combined with preexisting world data to scrutinize genetic relationships of A. cerana in South Korea to outside distributional range. Sequencing of 184 samples provided a total of ten haplotypes: five from Korea, six from China, one from Vietnam, and two from Thailand. Among them eight were new, whereas two were previously reported ones. Phylogenetic analysis of A. cerana NC2 haplotypes so far found including ours has confirmed the presence of four major groups of A. cerana (Asian mainland group, Sundaland group, Palawan group, and Luzon-Mindahnao group) and all haplotypes found in this study also were included in the Asian mainland group. In order to find further variable regions that can be used as sequence-based marker several mitochondrial non-coding regions and nuclear intron regions are in the middle of testing.
        15.
        2011.09 구독 인증기관 무료, 개인회원 유료
        Historically the rise of contagious diseases and epidemics has been mainly caused by lack of food safety knowledge and negligence in personal hygiene. Food poisoning is an example that have been caused by lack of proper knowledge in food safety and personal hygiene. In order to prove this hypothesis, our team distributed a total of 225 survey sheets to middle school students. Survey questions mainly focused on the students' food safety knowledge, personal hygiene and regular dietary habits. We used 12 items to determine the stages of change in teenagers and divided into 3 stages of change: precontemplation stage (poor problem recognition), contemplation and preparation stage (some problem recognition), and action stage. Out of the 225 students surveyed, 105(47.1%) were male and 118 (52.9%) were female; 44.0% were in 7th grade, 33.0% in 8th grade, and 24.0% in 9th grade. In stages of change model, 3.8% were classified in pre-contemplation stage, 31.1% in preparation stage, and 65.1% in action stage. The awareness of the significance of food safety has a strong positive correlation with the stages of change food safety behavior (P<0.001), which suggesting our questionnaires regarding stages of change and food safety behavior were quite credential. Stages of change were also correlated with the consumption of unsanitary foods (P<0.01) and with the frequent hand washing (P<0.05). The stages of change showed a positive correlation with the food safety knowledge level (P<0.05). The four questions (out of 10) with the least percentage of correct answers were questions about the meaning of Norovirus (23.6%), the meaning of expiration date (43.6%), the meaning of food poisoning (36.4%), and proper food-handling (36.0%).
        4,600원
        16.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        원자전달 라디칼 중합을 이용하여 poly(epichlorohydrine) (PECH)를 주사슬로 한 양친성 가지형 공중합체를 합성하였다. PECH로부터 poly(methyl methacrylate)(PMMA) 및 poly(butyl methacrylate)(PBMA)의 가지형 중합이 성공적임을 1H NMR과 FT-IR분석을 통해 확인하였다. 합성한 가지형 공중합체에 KI나 LiI 염을 도입하였을 때, ether 신축진동 피크가 낮은 wavenumber영역으로 이동하였으며, 이는 배위결합 상호작용 때문이다. PECH-g-PBMA 복합체의 이온 전도도는 PECH-g-PMMA 복합체에 비해 항상 높게 나타났는데, 이는 고무상인 PBMA 사슬의 높은 이동성으로부터 기인한 것으로 확인되었다. 최고 이온전도도 값은 질량비 10 wt%의 KI가 도입된 PECH-g-PBMA 전해질체에서 2.7 × 10 -5 S/cm로 나타났다.
        4,000원
        17.
        2008.05 구독 인증기관·개인회원 무료
        Bumblebees are important pollinators in greenhouse and have colonized all parts of the World. In Korea, the value of bumblebees is increasing as pollinator. However, the more recent use of reared colonies may ultimately allow pathogens to spread to peripheral areas for bumblebees. Generally, bumblebees are hosts to a large number of parasites which are mites, flies, protozoa, fungi, virus and bacteria. For most of these, very little is known about their effects against host insect, epidemiology or evolutionary ecology. So, we report pathogenic bacteria isolated from Bombus terrestris and B. ignitus at first time in Korea. Bacillus fusiformis and Klebsiella oxytoca are isolated from B. terrestris and confirmed with 16S rRNA gene nucleotide comparison in NCBI genebank. Pathogenicity of B. fusiformis was 35~40% against B. terrestris. Pantoea dispersa and K. oxytoca are isolated from B. ignitus and confirmed with 16S rRNA gene nucleotide comparison in NCBI genebank. Pathogenicity of these species were 35~40% against B. ignitus. These pathogenicity are considered as low-level.
        18.
        2007.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        국내 경수로원전 1차 냉각재와 중저준위 방사성폐기물 내 핵종방사능비에 대한 유관성을 검토하고자 특수하게 제작된 RCS sampling kit를 이용하여 원전 정상운전기간 동안 핵종을 포집하였다. 시료채취는 경수로형 전 원자력 발전소를 대상으로 2004년과 2005년에 걸쳐 시료를 채취하였고, 방사화학적 방법인 시료 전처리 및 핵종분리를 통하여 핵종 방사능을 분석하였다. RCS sampling kit 내 필터와 수지에서 분석된 핵종 방사능비는 각각 2.32-2와 7.3E-1을 보였으며, 동일주기 내 발생된 중 저준위 방사성폐기물인 농축폐액, 폐수지, 잡고체시료 내 핵종 방사능비는 각각 6.3E-1, 6.7E-1 및 5.7E-2로 시료유형 에 따라 1차 냉각재와 유사성을 갖는 것으로 확인하였다.
        4,000원
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