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        검색결과 38

        2.
        2023.10 구독 인증기관·개인회원 무료
        가송이(Tricholoma bakamatsutake Hongo)는 주름버섯목(Agaricales), 송이과(Tricholomataceae)에 속 하는 외생균근성 버섯류의 하나로, 송이(T. matsutake)와 일반적인 외형이 거의 비슷하며, 송이향과 맛이 강하게 나기 때문에 이 두 균종은 쉽게 혼동되며, 실제 분류 및 계통발생학적으로도 가송이와 송이는 유연 관계가 있는 것으로 밝혀졌다. 가송이는 한국, 일본, 대만, 중국의 신갈나무 등과 같은 활엽수림에 분포하는 것으로 알려져 있으며, 최근에는 제주도 구실잣밤나무림에서 발견되었다. 가송이는 균사생장이 매우 느려 연구에 어려움이 많아 균사배양 최적 조건을 구명하고자 본 연구를 실시하였다. 온도에 따른 가송이 균주 별 균사생장 특성을 조사한 결과, 모든 균주에서 25℃에서 가장 균사생장속도가 가장 빨랐으며, 특히 3833 균주가 다른 균주에 비해 약 1.5배 빠른 것으로 조사되었다.
        3.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To apply UV-C as a non-heating sterilization method to increase the microbiological safety of fresh seedless watermelon products, reductions in E. coli and quality changes by treatment dose (0, 2, 4, 8, 14, 20 kJ/m2) were investigated. The pH, sugar content, and hardness of watermelon inoculated with E. coli were not significantly different according to the UV-C treatment dose, but the polyphenol content was significantly decreased compared to the controls (425.4 GAE μg/g F.W.). When treated with 2 and 4 kJ/m2, the lycopene content was 31.6 and 30.9 μg/g F.W., respectively, which was increased compared to the controls (28.5 μg/g F.W.). The arginine and citrulline content was also significantly increased compared to the controls. The number of E. coli was significantly decreased compared to the controls following UV-C treatment. Considering the degree of E. coli reduction, lycopene content, arginine content, citrulline content, and UV-C irradiation time, subsequent experiments were conducted by selecting a UV-C treatment dose of 2 kJ/m2. The results of confirming the degree of reduction in the number of E. coli colonies by a single treatment and combined treatment with UV-C 2 kJ/m2 and 70% ethanol showed that the combined treatment was most effective as colonies were decreased by 2.3 log CFU/g compared to the controls. Therefore, it is judged that UV-C 2 kJ/m2 radiation and combined treatment with 70% ethanol could be applied as a non-heating sterilization method for fresh watermelon slices.
        4,000원
        4.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Influenza A viruses (IAVs) are members of the family Orthomyxoviridae and genus Orthomyxovirus. Avian and mammalian species are the host of IAVs, which includes humans and dogs. Canine influenza virus (CIV) is an emerging pathogen that causes severe and acute respiratory diseases in dogs. This study monitored the antigen and antibody against CIV in dogs in the Republic of Korea (ROK) from 2016 to 2021. One thousand and seventy-two nasal swabs and 1,545 blood samples were collected from animal hospitals and animal shelters. Five nasal swabs in 2017 and seven in 2018 from stray dogs were positive for CIV according to RT-PCR. The prevalence of H3N2 CIV ranged from 9.5% to 24.8%, according to the hemagglutination inhibition (HI) assay. On the other hand, none of the serum samples from 2018 to 2021 showed seropositivity against the avian H5, H7, and H9 viruses. The HI titers for H3N2 ranged from 16 to 512. The distribution of HI titer 16–32 was 57.6% in seropositive samples. The pet dogs were vaccinated against CIV, but the stray and military dogs were unvaccinated. In 2017 and 2018, the seroprevalence of CIV in stray dogs was higher than in the other years, and viral RNA was detected in nasal swabs. It may mean previous exposure of stray dogs to CIV. With the increasing number of pet dogs and the close contact between humans and dogs, canines could serve as an intermediate host for transmitting IAVs to humans. Therefore, continuous surveillance of CIV is needed for public health and the potential emergence of novel zoonotic viruses.
        4,000원
        5.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently microplastic (MP) biofilm is being attracted as an important environmental issue because it can act as a pollutant carrier in aqueous system. Therefore, this study investigated the MP biofilm communities originated from freshwater. The results showed the bacterial community structure of MP biofilm was distinctively different from the freshwater regardless of biofilm-forming condition and MP type. For MP biofilm communities exposed to raw freshwater, Solimonas variicoloris-like microbe, Frigidibacter albus-like microbe, Nitrospirillum amazonense-like microbe, and Pseudochroococcus couteii-like microbe became abundant, while Acinetobacter johnsonii, Macellibacteroides fermentans, and Sedimentibacter acidaminivorans-like microbe were found as major bacteria for MP biofilm communities exposed to organic rich condition. The results of this study suggest that the unique freshwater biofilm community could be formed on the MP surface.
        4,000원
        7.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In spite of the benefits of English oral presentations on EFL learners' proficiency and competence, English presentations have not obtained much attention as instructional medium in the field of English education. With the belief that EFL learners' experience of English presentation performance can provide valuable insights for educators and researchers, this study intended to describe how EFL learners perceive their presentation performance through their reflective self-assessment. In particular, adopting Otoshi and Heffernen's (2008) rubric of evaluation, this study examined what a group of Korean EFL learners were concerned in regard to their presentation performances and how they evaluated them. The data collected were 41 reflective self-assessment papers written by 41 Korean college students. The papers were coded, categorized and interpreted. Findings showed that voice quality is the area the students in this paper were most concerned about. Negative evaluations of their presentation performance outweighed the positive evaluations except in the area of Power Point use. Lastly, rehearsal and visual aids education sessions as well as differentiating spoken and written English were suggested as instruction implications for educators.
        6,000원
        8.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to evaluate the fixed wing type domestic UAV for monitoring of algae bloom in aquatic environment. The UAV used in this study is operated automatically in-flight using an automatic navigation device, and flies along a path targeting preconfigured GPS coordinates of desired measurement sites input by a flight path controller. The sensors used in this study were Sequoia multi-spectral cameras. The photographed images were processed using orthomosaics, georeferenced digital surface models, and 3D mapping software such as Pix4D. In this study, NDVI(Normalized distribution vegetation index) was used for estimating the concentration of chlorophyll-a in river. Based on the NDVI analysis, the distribution areas of chlorophyll-a could be analyzed. The UAV image was compared with a airborne image at a similar time and place. UAV images were found to be effective for monitoring of chlorophyll-a in river.
        4,000원
        9.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Scale formation is inevitable problem when seawater is treated by vacuum membrane distillation. The reason is the high concentration of calcium ion(Ca2+), sulfate ion(SO4 2-) and bicarbonate ion(HCO3 -). These ions form calcium sulfate(CaSO4) and calcium carbonate(CaCO3) on the membrane. The scale formed on membrane has to be removed, because the flux can be severely reduced and membrane wetting can be incurred. This study was carried out to investigate scale formation and effectiveness of acid cleaning in vacuum membrane distillation for SWRO brine treatment. It was found that permeate flux gradually declined until volume concentration factor(VCF) reached around 1.55 and membrane wetting started over VCF over 1.6 in the formation of precipitates containing CaSO4 during VMD operation. In contrast, when calcium carbonate formed on membrane, permeate flux was gradually reduced until VCF 3.0. The precipitates containing both CaSO4 and CaCO3 were formed on the membrane surface and in the membrane pore.
        4,000원
        10.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was carried out to enhance the availability of blackberry. Since it is difficult to use blackberry as a fresh fruit, we investigated the quality characteristics of blackberry powder obtained by various drying methods (freeze drying and hot-air drying at 40~80℃). The L- and b-values of freeze-dried powder was higher than hot-air dried powder. The pH (3.2) was lowest and the acidity (14.4%) was highest in freeze-dried powder. In freeze drying, the brix degree was 65.7 °Bx, but it increased from 54.7 °Bx to 68.5 °Bx with increasing temperature during hot air drying. The total polyphenol and flavonoids contents were the highest in freeze-dried powder, at 9.3 and 6.2 mg/g, respectively. The levels increased as temperature increased in hot air drying. Anthocyanin content in freeze-dried powder was 8.51 mg/g, while it sharply decreased to 1.17~2.45 mg/g in hot-air drying. Vitamin C content in freeze drying (979.4 μg/g) was higher than that in hot-air drying (48.3~303.2 μg/g). The sample concentration required for 50% reduction of DPPH free radical scavenging (RC50) was 79.7 μg/mL in freeze drying, and showed high antioxidant activity. Also it decreased from 122.4 μg/mL to 87.7 μg/mL with temperature increase during hot air drying. We therefore conclude from the above results that freeze drying is more suitable for the production of blackberry powder, because this method showed high value of chromaticity, total polyphenol, flavonoid, anthocyanin content, vitamin C and antioxidant activity.
        4,000원
        11.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        2013~2014년 동안 전북지역 블루베리에서 총 37종의 해충이 조사되었다. 주요해충은 블루베리혹파리, 목화진딧물, 갈색날개매미충, 볼 록총채벌레, 미국흰불나방, 장수쐐기나방 6종이었다. 목화진딧물 피해는 5월 중순 익산과 진안에서 심하게 발생하였다. 총채벌레 피해는 모든 지 역에서 개화기인 6월초에 심하였고, 어린묘에서 심하였다. 갈색날개매미충은 중산간지역인 순창과 진안지역에서 대발생하여 전 지역으로 확산 되고 있었다. 미국흰불나방은 6월 익산에서 특이적으로 집중 발생하는 경향이었다. 쐐기나방은 5종이 발생하였는데 그 중 장수쐐기나방이 모든 지역에서 발생밀도가 가장 높았다. 블루베리혹파리 피해는 중산간지대인 순창과 진안지역보다 평야지대인 익산지역에서 심하였고, 3년생 이하 어린 묘에서 피해율 60~78%로 5년생 이상 피해율 30~50%에 비하여 높았다. 또한, 하우스에서 피해율은 50~80%로 노지 피해율 30~40% 보 다 높게 나타났다.
        4,000원
        12.
        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
        13.
        2009.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        6,400원
        14.
        2008.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        6,600원
        16.
        2006.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of the present study is to compare the use of discourse markers by pre-service training students and in-service training teachers in middle school contexts. For this purpose, 20 participants in each of the pre-service (PS) and in-service (IS) teacher groups were selected and their teaching was videotaped. Then, the data was transcribed with a focus on the use of discourse markers. The results of the study demonstrated that there was no significant difference in the use of macro-markers between the two groups. However, it is interesting that student teachers in the PS group used various expressions for elaboration a little more frequently than the IS group. In addition, significant differences were found in the use of micro-markers between the two groups in terms of segmentation and temporal markers. On the basis of the results, some pedagogical implications on the teaching of listening and teacher training are suggested.
        5,200원
        19.
        2003.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        5,200원
        20.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        5,400원
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