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        검색결과 1,238

        541.
        2017.04 구독 인증기관·개인회원 무료
        The diamondback moth (DBM), Plutella xylostella, is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. Chlorantraniliprole is the first commercial insecticide that belongs to the new chemical class of diamide insecticides. In this study, the resistant strain was observed 1578-fold resistance to chlorantraniliprole. Point mutation (G4946E) in ryanodine receptor (RyR) showed a high frequency. Enzyme assays indicated that glutathione S-transferase (GST) activity in the resistant strain was 2.4 times higher compared with the susceptible strain, whereas no difference was seen for P450 and esterase. In addition, the expression of two GSTs genes was up-regulated. These findings pave the way for the complete understanding of the mechanisms of diamide insecticides resistance in insects.
        542.
        2017.04 구독 인증기관·개인회원 무료
        Dermanyssus gallinae is parasitic to chicken, and they cause many damages such as disturbing sleep reducing for body weight and egg production by blood-sucking. To develop acaricide against D. gallinae, The acaricidal activity of 40 species plant extract were examined. Cnidium officinale extracted by Me-OH showed 82.0% acaricidal activity after treated 48 hrs at 4,000 ppm. The hexane fraction showed 92.4% mortality against D. gallinae at 48 hrs at 2,000 ppm. Purification of the biologically active constituents from the hexane extraction with acaricidal activity was done using silica gel open column chromatography and HPLC. H1122 fraction gave 80.9% mortality to D. gallinae at 400 ppm after treated 48 hrs. H1122 fraction was analyzed by GC-MS and NMR.
        543.
        2017.04 구독 인증기관·개인회원 무료
        The diamondback moth, Plutella xylostella, is known worldwide as a pest that affects cruciferous plants. We surveyed insecticide susceptibility in chlorantraniliprole-resistant strain of P. xylostella to 13 insecticides (3 diamaids, 2 synthetic pyrethroids, 2 spinosyns, 1 organophosphorus, 1 carbamate, 1 marcrolide, and 3 others) to examine resistance ratios. The levels of insecticide resistance were extremely high, especially to chlorantraniliprole and flubendiamide. Enzyme assays indicated that glutathione S-transferase (GST) activity in the resistant strain was 2.4 times higher compared with the susceptible strain, whereas no difference was seen for P450 and esterase. Its F1 progeny resulting from reciprocal crosses with a susceptible strain revealed no maternal effects and a diamide susceptible phenotype, suggesting an autosomally almost recessive mode of inheritance.
        544.
        2017.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The current study explores the effects of different types of voice-based chat on EFL students’ negotiation of meaning according to proficiency levels. Participants included 123 Korean university students of English. They were divided into two voice-based chat groups: student-student voice-based chat and student-chatterbot voice-based chat. The experiment was administered throughout one semester, 16 weeks. Negotiation of meaning evident in the chats was coded for confirmation check, comprehension check, clarification requests, repetition, and reformulation, and was measured by counting the number of meaning negotiation moves. Important findings were as follows: Firstly, there were significant differences between the first chat and the last chat. The mean frequencies of negotiation moves at all proficiency levels positively changed over time as a result of participating in student-chatterbot voice-based chat. Particulalry, student-chatterbot voice-based chat, as compared to student-student voice-based chat, allowed students to use more negotiation strategies, and the strategies used in the chats also appeared to be different according to the students’ proficiency levels. Lastly, positive perceptions of voice-based chat were observed at all proficiency levels. This study provides empirical evidence to substantiate the effects of voice-based chatterbots in oral interaction. Based on the findings, pedagogical implications are made on the effective implementation of voice-based chatterbots in EFL contexts.
        6,000원
        545.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates how voice-chat conditions affect learners’ affective factors. In order to examine the effects of voice-chat conditions on Korean EFL learners’ attitudes towards English language learning and perceptions of voice-chat, 123 college students participated in this study. Participants were divided into two experimental groups: voice-chat with peers and voice-chat with robots. During the 16-experiment week, participants had a chat with either peers or robots. All participants in both voice-chat conditions showed positive attitudes towards English language learning and positive perceptions of voice-chat. Results indicate that both voice-chat conditions are effective in enhancing the learners’ confidence in English speaking, motivation to develop their English language skills, interests in English language learning, and beliefs in the improvement of their English speaking ability. In addition, engagement in voice-chat appears to help learners to reduce their stress and anxiety level. Findings suggest that EFL teachers integrate chat robots into their language teaching process.
        6,100원
        546.
        2017.03 구독 인증기관 무료, 개인회원 유료
        Dental caries is the most common chronic disease in the dental field. Streptococcus mutans (S. mutans) is the most important bacteria in the formation of dental plaque and dental caries. In a previous study, we confirmed that the essential oil of Chrysanthemum boreale has antibacterial activity against S. mutans. Alpha-pinene is one of the major chemical components of Chrysanthemum boreale essential oil. In the present study, we investigated the inhibitory effects of ɑ-pinene on cariogenic properties such as growth, acid production, biofilm formation, and bactericidal activity on S. mutans. Alpha-pinene at a concentration range of 0.25-0.5 mg/mL significantly inhibited the growth of S. mutans and acid production of S. mutans. Biofilm formation was significantly inhibited at > 0.0625 mg/mL ɑ-pinene, similar to the data from scanning electronic microscopy. Under confocal laser scanning microscopy, the bacterial viability was decreased by ɑ-pinene in a dose-dependent manner. These results suggested that ɑ-pinene may be a useful agent for inhibiting the cariogenic properties of S. mutans.
        4,000원
        547.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Many kinds of medicinal herbs have been used to treat inflammation in Oriental medicine. However, there few studies have investigated the anti-inflammatory activity of medicinal herbs. In this study, we used mouse bone marrow cells (BMs) treated with lipopolysaccharide (LPS), a simulator of osteomyelitis, to screen medicinal herbs having anti-inflammatory activity. Specifically, we investigated the activity of an extract of Rhus chinensis (RC) using metabolic activity and cytokine production of the BMs treated with LPS and RC. The metabolic activity of BMs was measured using Cell Counting Kit-8® solution. RC decreased the metabolic activity of LPS-treated BMs. A viability assay using trypan blue solution demonstrated that RC marginally decreased the viability of LPS-treated BMs. Flow cytometry analysis revealed that RC decreased the mitochondrial membrane potential of BMs, regardless of LPS treatment. To investigate the anti-inflammatory activity of RC, we measured the production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-10 in BMs. LPS increased the production of both cytokines in BMs. Interestingly, RC induced a greater increase in IL-10 than TNF-alpha in LPS-treated BMs. Taken together, RC decreased metabolic activity and modulated the production of inflammation-related cytokines in LPS-treated BMs. These findings suggest that RC can be used as a medicinal herb with anti-inflammatory activity.
        4,000원
        548.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report the use of carrot, a new and inexpensive biomaterial source, for preparing high quality carbon dots (CDs) instead of semi-conductive quantum dots for bioimaging application. The as-derived CDs possessing down and up-conversion photoluminescence features were obtained from carrot juice by commonly used hydrothermal treatment. The corresponding physiochemical and optical properties were investigated by electron microscopy, fluorescent spectrometry, and other spectroscopic methods. The surfaces of obtained CDs were highly covered with hydroxyl groups and nitrogen groups without further modification. The quantum yield of as-obtained CDs was as high as 5.16%. The cell viability of HaCaT cells against a purified CD aqueous solution was higher than 85% even at higher concentration (700 μg mL−1) after 24 h incubation. Finally, CD cultured cells exhibited distinguished blue, green, and red colors, respectively, during in vitro imaging when excited by three wavelength lasers under a confocal microscope. Offering excellent optical properties, biocompatibility, low cytotoxicity, and good cellular imaging capability, the carrot juice derived CDs are a promising candidate for biomedical applications.
        4,000원
        549.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ameloblastic fibrosarcoma (AFS) is an extremely rare malignant odontogenic tumor characterized with benign ameloblastic cells islands and malignant mesenchymal component. While two-thirds of AFS seem to arise de novo, but one-third develops from recurrent ameloblastic fibroma (AF) or ameloblastic fibro-odontomas (AFO). Pathological distinction of malignant transformation is essential for appropriate treatment. The patient was a 28 years old man. Since the primary tumor was excised, the mass recurred 2 years later. The recurrent tumor was diagnosed as AFS. Chief complaint was pain in the right mandible. Computer tomography finding revealed multilocular intrabony lesion with radiopaque substance in the primary lesion. In the recurrent lesion cortical bone destruction was found. Microscopically, both the primary and recurrent lesions showed benign ameloblastic follicles with myxoid or highly cellular mesenchymal proliferation. The histological difference between primary and recurrent lesions were that foci of dental hard tissue composed of enamel and dentin were found only in the primary lesion, whereas nuclear pleomorphism was aggrevated in the recurrent lesion. The histological criteria determining malignancy were discussed.
        4,000원
        550.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The unique characteristics of graphene make it an optimal material for crucial studies; likewise, its potential applications are numerous. Graphene’s characteristics change with the number of total layers, and thus the rapid and accurate estimation of the number of graphene layers is essential. In this work, we review the methods till date used to identify the number of layers but they incorporate certain drawbacks and limitations. To overcome the limitations, a combination of these methods will provide a direct approach to identify the number of layers. Here we correlate the data obtained from Raman spectroscopy, optical microscopy images, and atomic force microscopy to identify the number of graphene layers. Among these methods, correlation of optical microscopy images with Raman spectroscopy data is proposed as a more direct approach to reliably determine the number of graphene layers.
        4,000원
        551.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        고준위방사성폐기물 심층처분에서 처분안전성의 신뢰도를 향상시킬 수 있는 방안으로 그리고 처분 프로그램 개발 및 인허가를 위해 많은 나라들에서 자국에 적합한 safety case를 개발하고 있다. 본 연구에서는 방사성폐기물 처분을 위한 safety case 의 의의, 필요성, 개발과정들을 정리하고 소개하였다. 그리고 처분안전성을 safety case의 다양한 측면에서 논의하였다. 아울러 스위스, 일본, 미국, 스웨덴, 핀란드 등 해외의 safety case 개발 현황과 현재 KAERI에서 개발 중인 safety case의 개발 전략을 간략히 소개하였다. 고준위방사성폐기물 처분안전성의 신뢰도 향상을 위해 safety case 기반 하에서 어떤 노력들이 필요한지를 분석하였다. 그리고 국내 상황을 반영하여 신뢰할 수 있는 정보자료의 구축, 안전성 관련 과정들의 이해, 안전성 평가의 불확실성 저감, 이해당사자와의 의사소통, 공정성과 투명성 확보 등의 실행 방안을 제안하고 논의하였다. 본 논문에 제시된 내용들은 심층처분 safety case를 이해하고, 국내에서 개발하고 있는 고준위방사성폐기물 처분 safety case 개발을 통한 처분안전성 신뢰도 향상에 기여할 수 있을 것으로 기대한다.
        5,200원
        552.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 퇴비에 함유된 영양소 및 중금속 함량을 파악하고 상추 재배시 퇴비의 적정 시용 비율을 알아보고자 수행되었다. 실험을 위해 두가지 퇴비를 이용하였다. 첫 번째 퇴비는 미완숙 퇴비(CA)이며 두 번째 퇴비는 시중에서 판매되고 있는 완숙 퇴비(CB)이다. 각각의 퇴비는 인공토양을 0%, 25%, 50%, 75%로 혼합하여 사용하였다. 50%와 75%의 비율로 혼합한 CA의 pH는 각각 5.39, 5.50으로 측정되었으며 약 산성으로 나타났다. CA 및 CB를 75% 비율로 혼합할 경우, 총 탄소 함량은 각각 14.5%와 6.5%로 다른 비율의 퇴비에 비해 높았고 대조구에 비해 총 질소와 인 농도가 유의하게 증가하였다. 총 탄소함량은 CA퇴비를 인공토양에 75% 혼합한 실험구에서 가장 높게 나타났다. CA는 CB와 비교하여 퇴비화율, 질소, 인의 농도가 크게 증가하였다. CB 75% 혼합한 실험구에서 구리(128 mg kg-1), 아연(260 mg kg-1), 납(0.32 mg kg-1), 카드뮴(0.48 mg kg-1) 의 함량은 다른 혼합구에 비해 가장 많은 증가하였다. 특히 비소는 CA퇴비를 25% 혼합한 실험구와 CB퇴비를 75%, 50% 혼합한 실험구에서 가장 높았다(6.69 and 6.28 mg kg-1). CA실험구 중에서 상대적으로 낮은 염분 및 중금속 함량을 함유한 CA 25% 혼합한 실험구는 상추의 성장속도 및 엽면적 등이 CB에 비해 낮게 측정되어 최적의 성장조건은 아닌 것으로 사료된다. 따라서, CA를 사용하여 상추재배에 이용할 경우, 더 낮은 농도의 CA를 이용하는 것이 적당할 것으로 판단된다.
        4,000원
        553.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the antidiabetic effect of amaranth grain ethanol extract (AEE) in a diabetic animal model, db/db mouse. The mice were divided into 4 groups: normal control mice (C57BL/6J), diabetic mice (C57BL/6J db/db), diabetic mice fed a lower concentration of AEE (0.3 mg/kg), and diabetic mice fed a higher concentration of AEE (0.5 mg/kg). After 10 weeks of treatment, body weights, blood insulin levels and blood glucose levels of each group were compared. At the end of treatment, the results showed that both AEE supplemented groups had lower body weights than those in the diabetic groups although higher than those in the normal groups. Moreover, in both AEE supplemented groups, serum insulin levels were higher and blood glucose levels were lower than those in the diabetic groups although both values were higher than those in the normal groups. The results of this study suggest that AEE can alleviate many of the common symptoms of diabetes in diabetic mice and, therefore, has potential as a therapeutic supplement for normalization of blood glucose and insulin levels in humans.
        4,000원
        554.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fast, cheap and sufficient serodiagnostic tools needs to be developed for the early detectionof brucellosis. Currently the tools cannot differentiate an active infection from vaccinated, norcan it differentiate other bacterial infections with lipopolysaccharides, especially Yersiniainfections. In this study, we purified recombinant outer membrane protein 10 and 28(rOmp10,rOmp28), and a dipstick assay(indirect or sandwich) was constructed with single(rOmp10 orrOmp28) and combined rOmps(rOmp10 and rOmp28) from Brucella(B.) abortus 544 to evaluatebovine Brucella positive serum collected during the beginning of the Korean outbreak from2006 to 2015. In application with single rOmp, rOmp10(70%; indirect, 92.11%; sandwichdipstick) and rOmp28(72.5%; indirect, 86.84%; sandwich dipstick) had comparable results. Inaddition, results indicated that dipstick with combined rOmps(rOmps10 and rOmp28) weresuperior in detecting positive serum samples, at 85% indirect and 100% sandwich dipstick. Surprisingly, the results were the same in detecting negative results at 97.78% for both singleand combined indirect dipsticks. The dipstick tools with rOmp10 and rOmp28 would be usefulfor a rapid screen method for bovine brucellosis.
        4,000원
        555.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        부영양화를 일으키는 대표적인 영양물질인 질소와 인을 제거하기 위하여 많은 연구들이 진행되어오고 있다. 본 연구에서는 질소와 인을 제거하기 위하여 해수 및 해수염에 존재하는 마그네슘과 칼슘을 사용하여 스트루바이트와 수산화인회석을 만들어 침전을 시켰다. 실험의 목적은 해수와 해수염을 사용하여 pH와 농도의 변화에 따른 영양염의 제거율을 비교평가 하였다. 하수의 실험조건에서 해수를 사용한 결과 인의 제거율은 90 %, 질소의 제거율은 50 %로 나타났다. 또한 pH 9, 질소와 인의 농도 10 mM, Mg/PO43-, NH4+의 비율 2의 조건에서 해수염을 사용하여 실험한 결과 질소의 제거율은 90 %, 인의 제거율은 70 %로 나타났다. 상대적으로 인의 제거율이 높은 이유는 해수를 사용한 경우 질소와 인의 몰 농도의 차이에서 비롯되었으며, 해수염을 사용한 경우 해수에 포함된 칼슘이 인과 반응하여 수산화인회석으로 침전 제거되었다고 할 수 있다. 수중의 질소와 인을 제거를 위하여 해수와 해수염을 사용한 결과 높은 제거율을 나타내었다.
        4,000원