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        검색결과 490

        1.
        2024.04 구독 인증기관·개인회원 무료
        지속적인 기후변화로 인해 매개 곤충을 통한 다양한 신종감염병이 국제적으로 확산되고 있으며, 발생빈도 또한 증가하는 추세이다. 이러한 매개질병을 관리하기 위해서는 질병을 매개하는 매개체에 대한 정보와 지속적 인 모니터링이 필요하다. 이 연구는 제3급 법정 감염병으로 지정된 중증열성혈소판감소증후근(Severe Fever with Thrombocytopenia Syndrome, SFTS) 및 라임병(Lyme disease) 등의 매개체로 알려져 있는 참진드기를 대상으로 충남 당진 일대에서 2018년부터 2023년까지 총 6년, 4월-11월의 기간동안 월 1회 4개의 환경(무덤, 산길, 잡목림, 초지)에서 드라이아이스 유인트랩을 사용하여 발생밀도를 조사하였다. 그 결과 2018년 16,996마리, 2019년 16,698마리, 2020년 6,417마리, 2021년 7,380마리, 2022년 3,451마리, 2023년 3,465마리로, 총 54,407마리가 채집되 었으며, 초지에서 가장 많이 채집되었다. 채집된 참진드기는 2속 3종으로 작은소피참진드기(Haemaphysalis longicornis), 개피참진드기(H. flava), 일본참진드기(Ixodes nipponensis)이며, 작은소피참진드기 (H. longicornis) 가 42,489마리(78.09%)로 높은 우점도를 보였으며, SFTS 보유 여부를 확인하기 위해 RNA 추출 및 Nested RT-PCR 단계를 걸쳐 전기영동을 수행하였으나 양성 검체는 0건으로 확인되었다. 이러한 연구 결과는 SFTS의 주요 매개 체인 참진드기 발생 양상 파악 및 매개 질병 관리 전략 수립에 기초 자료로서 활용될 수 있을 것으로 사료된다.
        2.
        2024.04 구독 인증기관·개인회원 무료
        국립기상연구소의 보고에 의하면 최근 한반도의 기온 상승으로 인해 온대내륙성 기후형에 속했던 지점은 온대해양성 기후형으로, 온대해양성 기후형은 아열대습윤 기후형으로 변화하고 있다. 이러한 한반도의 기후 변화는 환경 변인에 민감한 질병 매개 곤충의 분포와 밀도 변화에 영향을 미칠 수 있어 지속적인 모니터링이 중요하다. 이 연구는 철새도래지 내 발생 및 유입될 수 있는 모기와 관련 바이러스 감염률을 확인하기 위해 충남 당진의 철새도래지에서 BG-sentinel trap 및 LED trap을 사용하여 2021년부터 2023년까지 4-11월간 월 2회 수행하 였다. 채집된 모기는 총 3,723마리로, 4속 16종을 확인하였다. 그 중 금빛숲모기 (Aedes (Aedimorphus) vexans nipponii) 가 1,711마리(45.96%)로 가장 높은 우점도를 나타냈으며, 흰줄숲모기 (A. (Stegomyia) albopictus) 와 큰검 정들모기 (Armigeres (Armigeres) subalbatus) 각각 588마리(15.79%), 빨간집모기 (Culex (Culex) pipiens pallens) 269마리(7.23%)로 나타났다. 채집된 모기의 Flavi-virus 감염 여부를 확인하기 위해 RNA 추출 및 RT-PCR을 통해 확인하였으나, 모두 음성으로 확인되었다. 이러한 연구 결과들은 기후변화에 맞추어 변화하는 감염병 매개 모기 의 발생 현황을 감시·예측하는데 유의한 자료로 활용될 수 있으며, 향후 모기 매개 질환 발생을 예측하기 위한 기초 자료로 활용될 수 있을 것으로 사료된다.
        3.
        2024.04 구독 인증기관·개인회원 무료
        털진드기 유충 (Acari: Trombiculidae)은 쯔쯔가무시증을 전파하는 주요 매개체이다. 털진드기 유충의 발생량 은 가을철에 증가하는 것으로 알려져 있지만, 환경 및 시기에 따라 발생 패턴이 다르게 나타날 수 있어 각 지역에 대한 조사가 필요하다. 이 연구는 충남 예산의 털진드기 발생 양상을 확인하기 위해 2017년부터 2023년까지 36-51 주차 (9-12월)에 걸쳐 현장 조사를 수행하였다. 논, 밭, 수로, 초지에 5m 간격으로 털진드기 트랩을 환경별로 5개씩 설치하여 채집하였다. 그 결과 총 3,257개체로 2017년 1,104마리, 2018년 785마리, 2019년 650마리, 2020년 160마 리, 2021년 139마리, 2022년 233마리, 2023년 186마리 채집되었다. 동정 결과 5속 12종이 확인되었으며 둥근혀털 진드기(Neotrombicula tamiyai)가 1,882개체(57.78%)로 우점도가 가장 높게 나타났다. 이러한 발생 양상에 관한 연구는 매개 질환의 예방 및 관리 전략 수립에 있어 중요한 기초 자료로 활용될 수 있으므로 지속적인 연구와 모니터링이 필요할 것으로 사료된다.
        4.
        2024.04 구독 인증기관·개인회원 무료
        The fall armyworm, Spodoptera frugiperda, has developed extremely high levels of resistance to chlorantraniliprole and other classes of insecticides in the field. As microRNAs (miRNAs) play important roles in various biological processes through gene regulation. we examined the miRNA profile of S. frugiperda in response to Chlorantraniliprole, Indoxacarb and Thiamethoxam. Transcriptome analysis showed significant changes in the abundance of some miRNAs after treatment of S. frugiperda larvae with LC20 concentrations of three insecticides. A total of 197 miRNAs were systematically identified from S. frugiperda, and 16, 9, 2 miRNAs were differentially expressed after treatments of three insecticides. Importantly, three miRNAs were significantly downregulated and three were upregulated by RT-qPCR after treatment the LC50 of three insecticides with S. frugiperda larvae. Microinjection of agomirs of these six miRNAs into S. frugiperda larvae resulted in significant changes in mortality rates when exposed to three insecticides. Additionally, we also screened potential target genes for some of differentially expressed miRNAs, which may play important roles in insecticide resistance development. These findings provide valuable insights into the molecular mechanisms of insecticide resistance and underscore the potential of miRNAs as targets for the development of novel pest control strategies in S. frugiperda.
        5.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the risk of single and combined exposure to microplastics in zebrafish (Danio rerio) through biomarkers, such as survival rate, excretion rate, and histological alterations of organ systems. The experimental groups were the control (Cont.), single microplastics exposure group (MPs, 1.83%/fish total weight (g)), the copper group (Cu, 21.6 μg L-1), and a group with combined exposure to MPs and copper (MPs*Cu). The experiment was conducted with individual exposure (7 days) for MP excretion rate analysis and group exposure (14 days) for biomarker analysis. The daily excretion rate of MPs tended to decrease in a time-dependent manner. The copper concentration in the body was not significantly different between single and combined copper exposure. The degeneration of mucous cells in the skin, capillary dilation of the gill lamella, increased intestinal mucous, hepatocyte hypertrophy, and the degeneration of glomeruli and renal tubules were observed in all exposure groups. These histological alterations showed the highest tendency in the MPs*Cu group. In this study, the changes in biomarkers were attributed to the single effect of copper or the combined effect of copper and MPs rather than being solely influenced by MPs.
        4,600원
        7.
        2023.11 구독 인증기관·개인회원 무료
        Molten Salt Reactor (MSR) is one of the 4th generation nuclear power systems which is its verified technology in physically and chemically. Among the various salts used for MSR system, the eutectic composition of NaCl-MgCl2 system maintains the liquid state at around 450°C, in the same time, it has high solubility for nuclear fuel chlorides. This characteristic has high advantage for lowering the operating temperature for the MSR, which could reduce the problem of hightemperature corrosion by salt for structural materials significantly. In particular, since MgCl2 has the similar standard reduction potential with nuclear fuel, is used as a surrogate for, many basic researches have been conducted for verifying characteristic of MgCl2. It is well-known that main short-advantage of MgCl2 is hygroscopic properties. MgCl2 changes to MgCl2-xH2O state easily by absorbing moisture in air condition. The hydrated MgCl2 is producing MgOHCl by thermally decomposing at high temperature, the formed MgOHCl corrodes structural materials, even small amount of MgOHCl gives significant damage. Therefore, the purification of MgCl2 has been required for long-term operation of MSR using MgCl2 as a base salt. In this study, the purification of eutectic composition salt for NaCl-MgCl2 has been mainly performed by considering its thermodynamic properties and electrochemical characteristic, and the experimental results have been discussed.
        8.
        2023.11 구독 인증기관·개인회원 무료
        In the nuclear fuel cycle (NFC) facilities, the failure of Heating Ventilation and Air Conditioning (HVAC) system starts with minor component failures and can escalate to affecting the entire system, ultimately resulting in radiological consequences to workers. In the field of air-conditioning and refrigerating engineering, the fault detection and diagnosis (FDD) of HVAC systems have been studied since faults occurring in improper routine operations and poor preventive maintenance of HVAC systems result in excessive energy consumption. This paper aims to provide a systematic review of existing FDD methods for HVAC systems therefore explore its potential application in nuclear field. For this goal, typical faults and FDD methods are investigated. The commonly occurring faults of HVAC are identified through various literature including publications from International Energy Agency (IEA) and American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). However, most literature does not explicitly addresses anomalies related to pressure, even though in nuclear facilities, abnormal pressure condition need to be carefully managed, particularly for maintaining radiological contamination differently within each zone. To build simulation model for FDD, the whole-building energy system modeling is needed because HVAC systems are major contributors to the whole building’s energy and thermal comfort, keeping the desired environment for occupants and other purposes. The whole-building energy modeling can be grouped into three categories: physics-based modeling (i.e., white-box models), hybrid modeling (i.e., grey-box models), and data-driven modeling (i.e., black-box models). To create a white-box FDD model, specialized tools such as EnergyPlus for modeling can be used. The EnergyPlus is open source program developed by US-DOE, and features heat balance calculation, enabling the dynamic simulation in transient state by heat balance calculation. The physics based modeling has the advantage of explaining clear cause-and-effect relationships between inputs and outputs based on heat and mass transfer equations, while creating accurate models requires time and effort. Creating a black-box FDD model requires a sufficient quantity and diverse types of operational data for machine learning. Since operation data for HVAC systems in existing nuclear cycle facilities are not fully available, so efforts to establish a monitoring system enabling the collection, storage, and management of sensor data indicating the status of HVAC systems and buildings should be prioritized. Once operational data are available, well-known machine learning methods such as linear regression, support vector machines, random forests, artificial neural networks, and recurrent neural networks (RNNs) can be used to classify and diagnose failures. The challenge with black-box models is the lack of access to failure data from operating facilities. To address this, one can consider developing black-box models using reference failure data provided by IEA or ASHRAE. Given the unavailability of operation data from the operating NFC facilities, there is a need for a short to medium-term plan for the development of a physics-based FDD model. Additionally, the development of a monitoring system to gather useful operation data is essential, which could serve both as a means to validate the physics-based model and as a potential foundation for building data-driven model in the long term.
        9.
        2023.11 구독 인증기관·개인회원 무료
        The presence of organic components in spent scintillation liquid should be considered during all steps of radioactive waste processing for final disposal. Scintillation liquids often referred to as cocktails are generated form radiochemical analyses of radionuclides, which mainly consists of mixtures of liquid organic materials such as toluene and xylene. Typical features of these liquid organic materials are volatility, combustibility and toxicity. These are the reason why special attention must be paid to the management of liquid organic radioactive wastes. To select an appropriate waste management strategy and to design the treatment process of spent scintillation cocktails, it is required to investigate the nature of the waste such as specific radioactivity and moisture content. The analysis results of spent scintillation liquid generated at Wolsong nuclear power plants will be discussed. An overview of the technical approaches available for the treatment of organic radioactive waste will be additionally provided.
        10.
        2023.11 구독 인증기관·개인회원 무료
        The occurrence of shear failure in a rock mass, resulting from the sliding of joint surfaces, is primarily influenced by the surface roughness and contact area of these joints. Furthermore, since joints serve as crucial conduits for the movement of water, oil, gas, and thermal energy, the aperture and geometric complexity of these joints have a significant impact on the hydraulic properties of the rock mass. This renders them critical factors in related industries. Therefore, to gain insights into the mechanical and hydraulic behavior of a rock mass, it is essential to identify the key morphological characteristics of the joints mentioned above. In this study, we quantified the morphological characteristics of tensile fractures in granitic rocks using X-ray CT imaging. To accomplish this, we prepared a cylindrical sample of Hwang-Deung granite and conducted splitting tests to artificially create tensile fractures that closely resemble rough joint surfaces. Subsequently, we obtained 2D sliced X-ray CT images of the fractured sample with a pixel resolution of approximately 0.06 mm. By analyzing the differences in CT numbers of the rock components (e.g., fractures, voids, and rock matrix), we isolated and reconstructed the geometric information of the tensile fracture in three dimensions. Finally, we derived morphological characteristics, including surface roughness, contact area, aperture, and fracture volume, from the reconstructed fracture.
        11.
        2023.11 구독 인증기관·개인회원 무료
        Rock discontinuities in underground rock behave as weak planes and affect the safety of underground structures, such as high-level radioactive waste disposal and underground research facilities. In particular, rock discontinuities can be a main flow path of groundwater and induce large deformation caused by stress disturbance or earthquakes. Therefore, it is essential to investigate the characteristics of rock discontinuities considering in-situ conditions when constructing highlevel radioactive waste disposal, which needs to assure the long-term safety of the structure. We prepared Hwang-Deung granite rock block specimens, including a saw-cut rock surface, to perform multi-stage direct shear tests as a preliminary study. In the multi-stage direct shear tests, we can exclude possible errors induced by different specimens for obtaining a full failure envelope by using an identical specimen. We applied the initial normal stress of 3 MPa on the specimen and increased the normal stress to 5 and 10 MPa step by step after peak shear stress observation. We obtained the mechanical properties of saw-cut rock surfaces from the experiments, including friction coefficient and cohesion. Additionally, we investigated the effect of filling material between rock discontinuities, assuming the erosion and piping phenomenon in the buffer material of the engineering barrier system. When the filling material existed in the rock surfaces, the shear characteristics deteriorated, and the effect of bentonite was dominant on the shear behavior.
        12.
        2023.11 구독 인증기관·개인회원 무료
        Molten salt reactor (MSR) uses fluoride or chloride based molten salt as a coolant of the system, and fuel materials are dissolved in the molten salt, therefore it can be act as both coolant and nuclear fuel. A few issues have arisen from early-stage research and development program of MSR from Oak Ridge National Laboratory, including corrosion of structural materials and fission product management. For investigating the effect of additives on corrosion of structural materials, Mg(OH)2 and MgCl2*6H2O are added into the NaCl-MgCl2 eutectic salt. Prepared chloride salt is injected into the autoclave in the glove box, as well as corrosion coupons for candidate structural materials for molten chloride salt reactor, SS316, Alloy 600, and C-276 are also prepared. The temperature is set as 700°C. After 500 h corrosion experiment, the samples are taken out from the autoclave, and they are analyzed with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). SS316 samples show weight loss with all salt conditions, while Alloy 600 and C-276 show weight gain after the corrosion experiment.
        13.
        2023.10 구독 인증기관·개인회원 무료
        During the larval development process of insects, juvenile hormone (JH) is essential for regulating various aspects of larval life, including growth, reproduction, and behavior, throughout their larval stage. The larval stage of Spodoptera frugiperda, when it consumes plant-derived metabolites, develops into pupae, but these pupae are unable to molt successfully. In this way, plant-derived metabolites contain or produce inhibitors of juvenile hormone, thereby disrupting the development of insect larvae and making them vulnerable to harm. Therefore, in this study, we established an in vitro screening system using yeast cells transformed with the Met-SRC juvenile hormone receptor of S. frugiperda. Through this system, we were able to identify juvenile hormone disruptors from plant-derived metabolites and confirm their developmental inhibitory effects on the larvae of S. frugiperda.
        14.
        2023.10 구독 인증기관·개인회원 무료
        기존에는 생산되는 키틴과 키토산의 대부분이 게, 새우등 갑각류 껍질에서 유래하였다. 하지만 어업에 의존하 는 기존 갑각류 비해 친환경적이며 품질 유지에 이점을 가지는 곤충으로부터 유래한 키틴이 최근 주목 받기 시작 하며 연구가 활발해지고 있다. 이에 키토산이 남조류의 응집을 통해 녹조 제거 효과를 가지며 기존에 녹조를 억제하기 위해 널리 사용되던 살조제들이 독성을 띠어 환경에 악영향을 미치는 문제를 해결할 수 있다는 연구를 참고하여 매미 탈피각으로부터 추출한 키토산을 녹조 방제에 활용해 보고자 하였다. 매미 탈피각으로부터 키토 산을 추출하고 대표적인 녹조 원인종인 Microcystis aeruginosa 배양 후 추출한 키토산을 처리하여 녹조의 응집 효과를 관찰하였다. 본 연구에서 새로운 키토산 추출 원으로서 매미 탈피각의 가능성을 제시하였으며 이를 녹조 방제에 활용함으로써 버려지는 자원인 매미 탈피각의 활용 방안을 제시하였다.
        16.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Buckwheat (Fagopyrum esculentum), which is a traditional Korean crop, has been known as a health food due to its rich nutrition. This study was conducted to evaluate the change in flavonoid content of flowers and seeds during post-flowering growth of Korean tartary buckwheat variety ‘Hwanggeummiso’, with the aim of providing basic data for the development of functional food and feed additive. Tartary buckwheat took 69 and 99 days from the sowing date to reach the flowering and maturity stages, respectively. As a result of examining the flavonoid components of each part of tartary buckwheat, chlorogenic acid, rutin, and isoquercitrin of flowers increased from the flowering period on 22 May (0 days after flowering) to 42 days after flowering, while quercetin increased until 21 days after flowering and then decreased thereafter. In seeds, chlorogenic acid, rutin, and isoquercitrin were most abundant at the time of seed-bearing on 14 days after flowering, and showed a decreasing tendency thereafter. On the other hand, quercetin showed a tendency to increase until 21 days after flowering and then decrease. Overall, the flavonoid content was higher in flowers than in seeds, with rutin being particularly prominent. Based on this, the possibility as food materials and feed additives was confirmed using buckwheat produced in Korea.
        4,000원
        17.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated ethopabate (EPB) residues in edible tissues of broiler chickens given in drinking water and established the withdrawal time (WT) of EPB in poultry tissues. Twenty-four healthy Ross broiler chickens were orally administered with EPB at the concentration of 3.8 mg/L for 14 days (EPB-1, n=24) and 15.2 mg/L for 7 days (EPB-2, n=24) through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 0, 1, 3, and 5 days, respectively. EPB residue concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient values ranged from 0.9980 to 0.9998, and the limits of detection and quantification (LOQ) were 0.03~0.09 and 0.1~0.3 μg/kg, respectively. Mean recoveries in muscle, liver, kidney and skin/fat tissues were 95.9~109.8, 108.7~115.3, 89.9~96.6 and 86.7~96.8%, respectively, and coefficient of variations were less than 17.11%. At the end of the drug-administration period (0 day), EPB was detected at levels under the LOQ in all tissues from both the EPB-1 and EPB-2 groups. According to the results of EPB residue in Ross broiler tissues, withdrawal periods of both EPB-1 and EPB-2 in poultry tissues were established to 0 day. In conclusion, the developed analytical method is suitable for the detection of EPB in poultry tissues, and the estimated WT of EPB in poultry tissues will contribute to ensuring the safety of Ross broiler chickens.
        4,000원
        18.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As platforms become primary decision making tools, platforms for decision have been introduced to improve quality of decision results. Because, decision platforms applied augmented decision-making process which uses experiences and feedback of users. This process creates a variety of alternatives tailored for users’ abilities and characteristics. However, platform users choose alternatives before considering significant quality factors based on securing decision quality. In real world, platform managers use an algorithm that distorts appropriate alternatives for their commercial benefits. For improving quality of decision-making, preceding researches approach trying to increase rational decision -making ability based on experiences and feedback. In order to overcome bounded rationality, users interact with the machine to approach the optional situation. Differentiated from previous studies, our study focused more on characteristics of users while they use decision platforms. This study investigated the impact of quality factors on decision-making using platforms, the dimensions of systematic factors and user characteristics. Systematic factors such as platform reliability, data quality, and user characteristics such as user abilities and biases were selected, and measuring variables which trust, satisfaction, and loyalty of decision platforms were selected. Based on these quality factors, a structural equation research model was created. A survey was conducted with 391 participants using a 7-point Likert scale. The hypothesis that quality factors affect trust was proved to be valid through path analysis of the structural equation model. The key findings indicate that platform reliability, data quality, user abilities, and biases affect the trust, satisfaction and loyalty. Among the quality factors, group bias of users affects significantly trust of decision platforms. We suggest that quality factors of decision platform consist of experience-based and feedback-based decision-making with the platform's network effect. Through this study, the theories of decision-making are empirically tested and the academic scope of platform-based decision-making has been further developed.
        4,600원
        19.
        2023.07 구독 인증기관·개인회원 무료
        Over the past decade, in-feed native advertising has become one of the most popular forms of online advertising, attracting attention from both academia and industry. Compared to traditional online ads, in-feed native ads are less intrusive and have more engaging content, effectively reducing users' tendency to avoid ads and improving advertising effectiveness. Despite existing review studies, most of them focus on specific aspects of in-feed native advertising, such as ad identification, disclosure, or regulation, and lack an overview of the relevant literature. Moreover, with the diversified development of digital media forms, the widespread application of AI technologies, and the improvement of consumers' ad literacy, in-feed native ad research faces new issues and practical challenges. Thus, a systematic review of existing research is necessary to identify valuable future research directions.
        20.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        From 2020, Korean Animal and Plant Quarantine Agency has reset the withdrawal time (WT) for veterinary drugs typically used in livestock in preparation for the introduction of positive list system (PLS) program in 2024. This study was conducted to reset the MRL for amprolium (APL) in broiler chickens as a part of PLS program introduction. Forty-eight healthy Ross broiler chickens were orally administered with APL at the concentration of 60 mg/L (APL-1, n=24) for 14 days and 240 mg/L (APL-2, n=24) for 7 days through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 0, 1, 3 and 5 days, respectively. Residual APL concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient (0.99 >), the limits quantification (LOQ, 0.3~5.0 μg/kg), recoveries (81.5~112.4%), and coefficient of variations (<15.5%) were satisfied the validation criteria of Korean Ministry of Food and Drug Safety. In APL-1, APL in all tissues except for kidney was detected less than LOQ at 3 days after drug treatment. In APL-2, APL in liver and kidney was detected more than LOQ at 5 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal periods of APL-1 and APL-2 in poultry tissues were established to 3 and 2 days, respectively. In conclusion, the developed analytical method is sensitive and reliable for detecting APL in poultry tissues. The estimated WT of APL in poultry tissues is longer than the current WT recommendation of 2 days for APL in broiler chickens.
        4,000원
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