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        검색결과 70

        2.
        2023.11 구독 인증기관·개인회원 무료
        Radiation workers, especially those dealing with Uranium isotopes, can potentially intake Uranium -containing materials through their respiratory and digestive systems. According to the “Regulations on the Measurement and Calculation of Internal Exposure” from Nuclear Safety and Security Commission (NSSC), those who intend to work in or enter the nuclear facilities with a risk of exceeding 2 mSv exposure per year should be examined the internal exposure. However, when it comes to in-vitro bioassay, Uranium intake through drinking water can affect the quantitative analysis. The International Commission on Radiological Protection (ICRP) reported in ICRP Publication 23 (Report on the Task Group on Reference Man) that the reference man excretes Uranium in the urine (0.05-0.5 μg/day) and feces (1.4-1.8 μg/day). Korea Atomic Energy Research Institute (KAERI) set the 90.5 ng/day as the 238U background of workers handing Uranium based on the daily Uranium intake of Koreans. In this research, we examined the possible effects of Uranium in drinking water on internal exposure by analyzing the concentration of Uranium in bottled waters from various water sources sold in the domestic market and a water from the water purifier. The 238U concentration results of analyzing 11 bottled waters and 1 purified water, were ranged from 0 to 10.2 μg/L. All the results were satisfied the standard of 30 μg/L according to “Regulations for Drinking Water Quality Standards and Inspection” enacted by the Ministry of Environment. However, various concentrations were shown depending on the water sources. Assuming that these concentrations of water are consumed by drinking 1 L per day, the internal dose assessment result is 0 to 0.94 mSv. On the other hand, if it is assumed to be inhaled, it can be an overestimated because the dose coefficient of inhalation, Type M is higher than that of ingestion, f1=0.02 which are the values recommended by ICRP Publication 78 (Individual Monitoring for Internal Exposure of Workers) when the Uranium compound is unspecified. In case of two workers at KAERI, the daily excretion of urine was 151 and 120 ng/day respectively in the first quarter monitoring. However after changing the kind of drinking water in the second quarter monitoring, it dropped to 17.4 and 15.4 ng/day respectively. Through this study, it is confirmed that the Uranium background in urine can be analyzed differently depending on the kind of drinking water consumed by each worker. Depending on the Uranium concentration of drinking water, the internal exposure dose assessment can be overestimated or underestimated. Therefore, the Uranium concentration and intake amount according to the kind of drinking water should be considered for in-vitro bioassays of Uranium handlers. Furthermore, if necessary, the Uranium isotope ratio analysis in urine and the handling information should be comprehensively considered. In addition, in order to exclude the effect of intake through the digestive system, replacing the kind of drinking water can be considered. The additional analysis such as in-vivo bioassay and 24 hours urine analysis rather than spot samples can be also recommended.
        3.
        2023.11 구독 인증기관·개인회원 무료
        Activated carbon (AC) is used for filtering organic and radioactive particles, in liquid and ventilation systems, respectively. Spent ACs (SACs) are stored till decaying to clearance level before disposal, but some SACs are found to contain C-14, a radioactive isotopes 5,730 years halflife, at a concentration greater than clearance level concentration, 1 Bq/g. However, without waste acceptance criteria (WAC) regarding SACs, SACs are not delivered for disposal at current situation. Therefore, this paper aims to perform a preliminary disposal safety examination to provide fundamental data to establish WAC regarding SACs SACs are inorganic ash composed mostly of carbon (~88%) with few other elements (S, H, O, etc.). Some of these SACs produced from NPPs are found to contain C-14 at concentration up to very-low level waste (VLLW) criteria, and few up to low-level waste (LLW) criteria. As SACs are in form of bead or pellets, dispersion may become a concern, thus requiring conditioning to be indispersible, and considering VLL soils can be disposed by packaging into soft-bags, VLL SACs can also be disposed in the same way, provided SACs are dried to meet free water requirement. But, further analysis is required to evaluate radioactive inventory before disposal. Disposability of SACs is examined based on domestic WAC’s requirement on physical and chemical characteristics. Firstly, particulate regulation would be satisfied, as commonly used ACs in filters are in size greater than 0.3 mm, which is greater than regulated particle size of 0.2 mm and below. Secondly, chelating content regulation would be satisfied, as SACs do not contain chelating chemicals. Also, cellulose, which is known to produce chelating agent (ISA), would be degraded and removed as ACs are produced by pyrolysis at 1,000°C, while thermal degradation of cellulose occurs around 350~600°C. Thirdly, ignitability regulation would be satisfied because as per 40 CFR 261.21, ignitable material is defined with ignition point below 60°C, but SACs has ignition point above 350°C. Lastly, gas generation regulation would be satisfied, as SACs being inorganic, they would be targeted for biological degradation, which is one of the main mechanism of gas generation. Therefore, SACs would be suitable to be disposed at domestic repositories, provided they are securely packaged. Further analysis would be required before disposal to determine detailed radioactive inventories and chemical contents, which also would be used to produce fundamental data to establish WAC.
        4.
        2023.11 구독 인증기관·개인회원 무료
        Domestic waste acceptance criteria (WAC) require flowable or homogeneous wastes, such as spent resin, concentrated waste, and sludge, etc., to be solidified regardless of radiation level, to provide structural integrity to prevent collapse of repository, and prevent leaching. Therefore, verylow level (VLL) spent resin (SR) would also require to be solidified. However, such disposal would be too conservative, considering IAEA standards do not require robust containment and shielding of VLL wastes. To prevent unnecessary cost and exposure to workers, current WAC advisable to be amended, thus this paper aims to provide modified regulation based on reviewed engineering background of solidification requirement. According to NRC report, SR is classified as wet-solid waste, which is defined as a solid waste produced from liquid system, thus containing free-liquid within the waste. NRC requires liquid wastes to be solidified regardless of radiation level to prevent free liquid from being disposed, which could cause rapid release of radionuclides. Furthermore, considering class A waste does not require structural integrity, unlike class B and C wastes, dewatering would be an enough measure for solidification. This is supported by the cases of Palo Verde and Diablo Canyon nuclear power plants, whose wet-solid wastes, such as concentrated wastes and sludge, are disposed by packaging into steel boxes after dewatering or incineration. Therefore, dewatering VLL spent resin and packaging them into structural secure packaging could satisfy solidification goal. Another goal of solidification is to provide structural support, which was considered to prevent collapse of soil covers in landfills or trenches. However, providing structural support via solidification agent (ex. Cement) would be unnecessary in domestic 2nd phase repository. As the domestic 2nd phase repository is cementitious structure, which is backfilled with cement upon closure, the repository itself already has enough structural integrity to prevent collapse. Goldsim simulation was run to evaluate radiation impact by VLL SR, with and without solidification, by modelling solidified wastes with simple leaching, and unsolidified wastes with instant release. Both simulations showed negligible impact on radiation exposure, meaning that solidifying VLL SR to delay leaching would be irrational. Therefore, dewatering VLL SR and packaging it into a secure drum (ex. Steel drum) could achieve solidification goals described in NRC reports and provide enough safety to be disposed into domestic repositories. In future, the studied backgrounds in this paper should be considered to modify current WAC to achieve efficient waste management.
        5.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 사료내 비테인, 글라이신, 그리고 콜린의 혼합 첨가가 고온 스트레스 환경에서 노령 산란계의 생산성, 난품질, 면역 반응 및 혈액성상에 미치는 영향을 조사하고자 수행되었다. 총 336마리의 86주령 로만 갈색종 노령 산란계를 6처리 7반복, 반복당 8수씩 임의 배치하였다. 대조구는 모든 영양소 및 에너지 요구량을 충족하거나 초과하도록 배합하였다. 대조구를 제외한 사료 처리구는 0.2% 비테인, 0.62% 글라이신, 그리고 0.32% 콜린을 단독, 두 가지 혼합, 혹은 세 가지 혼합으로 사료내 첨가하였다. 실험은 8주 동안 진행되었으며, 모든 산란계는 매일 8시간 동안 평균 온도 31.7±1.7℃, 습도 57%의 고온 스트레스 조건에서 사양되었고, 이외 시간에는 평균 온도 27±1.3℃, 습도 57%에서 사양하였다. 실험 결과, 비테인, 글라이신 및 콜린의 첨가는 생산성, 난품질, 그리고 면역 반응에 유의적인 영향을 미치지 않았다. 그러나, 0.2% 비테인과 0.62% 글라이신을 혼합 첨가한 처리구에서 혈청 알라닌 아미노전이효소 농도가 유의적으로 감소했다. 하지만, 다른 혈청 지표들은 처리간 유의적인 차이가 관찰되지 않았다. 결론적으로, 현재 수준에서 사료내 비테인, 글라이신, 그리고 콜린의 혼합 첨가는 고온 스트레스 환경에서 사양되는 노령 산란계의 생산성, 난품질, 면역 반응 및 혈액 성상에 긍정적인 영향을 미치지 않는다고 판단된다.
        4,000원
        6.
        2023.10 구독 인증기관·개인회원 무료
        Bombyx mandarina (Lepidoptera: Bombycidae), the presumed ancestor of B. mori, has long been a subject of study to illustrate the geographic relationships in connection with origin of B. mori. We report 97 mitochondrial genome (mitogenome) sequences of B. mandarina collected from Korea and Japan. Phylogenetic and population genetic analyses showed that all individuals of B. mandarina collected in Korean localities formed a strong group together with all individuals originated from northern China (mainly north of the Qinling-Huaihe line) and some of southern China. This group was placed as the sister group to B. mori strians suggesting that this group had been served as an immediate progenitor for B. mori.
        7.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was aimed to isolate bacterial inoculants producing chitinase and evaluate their application effects on corn silage. Four corn silages were collected from four beef cattle farms to serve as the sources of bacterial inoculants. All isolates were tested against Fusarium graminearum head blight fungus MHGNU F132 to confirm their antifungal effects. The enzyme activities (carboxylesterase and chitinase) were also measured to isolate the bacterial inoculant. Based on the activities of anti-head blight fungus, carboxylesterase, and chitinase, L. buchneri L11-1 and L. paracasei L9-3 were subjected to silage production. Corn forage (cv. Gwangpyeongok) was ensiled into a 10 L mini silo (5 kg) in quadruplication for 90 days. A 2 × 2 factorial design consists of F. graminearum contamination at 1.0104 cfu/g (UCT (no contamination) vs. CT (contamination)) and inoculant application at 2.1 × 105 cfu/g (CON (no inoculant) vs. INO (inoculant)) used in this study. After 90 days of ensiling, the contents of CP, NDF, and ADF increased (p<0.05) by F. graminearum contamination, while IVDMD, acetate, and aerobic stability decreased (p<0.05). Meanwhile, aerobic stability decreased (p<0.05) by inoculant application. There were interaction effects (p<0.05) on IVNDFD, NH3-N, LAB, and yeast, which were highest in UCT-INO, UCT-CON, CT-INO, and CT-CON & INO, respectively. In conclusion, this study found that mold contamination could negatively impact silage quality, but isolated inoculants had limited effects on IVNDFD and yeast.
        4,000원
        11.
        2019.06 구독 인증기관 무료, 개인회원 유료
        본 리뷰는 한국의 중요한 수산자원인 살오징어(Todarodes pacificus)의 동해와 서해 어획량 변동 원인을 살오징어 난/자치어 수송부터 회유경로 및 어장 분포에 관점으로 논의하였다. 우리나라 살오징어 어획량은 1980년 이후 기후체제전환에 따라 변화가 있어 왔으며 이는 동해와 서해의 어획량 변동 경향이 달랐다. PDO (Pacific Decadal Oscillation)는 동해로 유입되는 난류 수송량과 음의 상관관계가 있는데 PDO가 양의 위상이었던 1980s에는 서해에서는 어획량이 많았고 동해 에서는 어획량이 적었다. 반면, PDO가 음의 위상이었던 1990s년대에는 동해 어획량이 많고 서 해에서는 적었다. 이는 살오징어가 난류를 따라 북상하거나 난류를 거슬러 남하회유를 하는 생활사에 기인된다. 동해의 경우, 난류가 강(약)할 때, 난류경로가 한국의 동해 연안 쪽(동해 중 부 해역 및 일본 연안 쪽)으로 치우치게 되는데 이는 PDO가 양의 위상이었던 1980년대에 어 장이 울릉도 동편에 위치하였던 반면 PDO가 음의 위상이었던 1990년대에 어장이 동해 연안 에 위치한 것과 관련있다. 서해 살오징어 어획량이 증가한 1980년대에는 동해로 유입되는 난 류수 수송량이 감소한 반면 서해로 유입되는 난류수는 증가하였으며 이는 서해로 수송되는 유 생의 양을 증가시키는 주요 원인이 된다.
        4,000원
        12.
        2019.04 구독 인증기관·개인회원 무료
        Malaria is notorious disease to transmitted by Anopheline mosquitoes. In Korea, Plasmodium vivax malaria was re-introduce in 1993 and exceed to more than 4,000 cases in early 2000s. Based upon our control efforts, it was sharply decreased and diagnosis 576 cases in last year. We made Action Plan in this year for certification of malaria elimination by WHO until year 2024. In this plan, we need to strengthen our capacity of vector surveillance and control. For vector surveillance, we will introduce daily mosquito population monitoring system. In 2020, every malaria high risk area install two mosquito counters and send information to main server. For vector control, we will try building capacity of malaria mosquito control people in the Public Health center and military section. To decrease no. of mosquitoes, we will concentrate our resource to cattle shed, which is main blood source of Anopheline mosquitoes. Based on the ecological characteristic of Anopheline, we will adopt Integrate Vector management (IVM) including physical, chemical and biological method. Based on the reconciliation with North Korea, we will support technical and material support for malaria elimination.
        17.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        층면구조 안정성 다이어그램은 층면구조가 주어진 입도와 유속에서 나타나는 층면구조의 모양과 크기를 지시한다. 이 다이어그램은 대부분 수조실험에 의해 획득한 실험 데이터를 기반으로 작성되었다. 일반적으로, 수조실험은 입자의 크기와 유속사이의 관계를 이해하기 위해 분급이 좋고 단일입도의 분포를 보이는 퇴적물을 이용하여 수행되었다. 이 다이어그램에 의하면, 세립사와 중립사 퇴적물 표면에서 유속이 빨라지면서, 평행층에서 연흔이 형성되기 시작한다. 이 연구의 목적은 층면구조 안정성 다이어그램의 결과가 실험을 통하여 잘 재현되는지를 확인하고, 분급이 좋은 퇴적물과 달리 분급이 불량한 경우인 이정 입도 분포를 보이는 사질 퇴적물에서도 잘 재현되는지 확인하는 것이다. 본 연구 실험 결과는 2D 연흔이나 3D 연흔 층면구조가 형성되기 위해서, 분급이 불량한 퇴적물의 경우에, 분급이 좋은 퇴적물보다 더 높은 유체의 유속과 전단응력이 필요하다는 것을 보여주고 있다. 탄산염 퇴적물은 수력학적 분급작용이 활발하지 않으며, 퇴적물의 구성이 알로켐과 기질로 이루어지는 이정 입도 분포를 보이는 퇴적물로서 일반적으로 분급이 불량한 특징을 가지고 있다. 따라서, 실험의 결과는 탄산염 퇴적물에서 층면구조 형성을 위해 쇄설성 퇴적환경의 퇴적물 보다 더 높은 유속이 필요할 수 있음을 제안하고 있다. 분급이 불량한 퇴적물 입자가 침식되어 이동기 위해 더 높은 에너지와 유속이 필요하다는 것은 분급 효과, 마찰 효과, 안정성 효과, 갑옷 효과 등이 복합적으로 작용한 결과로 설명될 수 있을 것이다. 본 연구는 예비적 고찰로서, 이어지는 연구를 통해 이러한 현상을 과학적으로 설명하고 입도와 층면구조 형성의 상관성을 보다 정교하게 규명하고자 한다.
        4,300원
        19.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cinnamaldehyde is known to have the antitumor effects in vitro and in vivo. In this study, we showed a potent and irreversible cytotoxic activity of the Cinnamaldehyde derivative 2'-benzoyloxycinnamaldehyde (BCA) in human Squamous oral cell carcinoma cell, YD-10B. BCA induced YD-10B cell apoptosis in a dose-responsive manner. BCA-induced apoptosis was associated with corresponding increases in a series of key components in the mitochondria-mediated apoptosis pathways, followed by caspase cleavage and PARP activation. We also observed that BCA induced autophagy through Akt/mTOR pathway in YD-10B cells. BCA treatment increased LC3B-II expression, and induced the formation of autophagosomes and autophagic vacuoles. These experimental findings suggest that BCA is a potent inhibitor of cell proliferation in YD-10B cells and provide new insights about leading to the possible development of a new therapeutic agent.
        4,000원
        20.
        2014.04 구독 인증기관·개인회원 무료
        The intracellular endosymbiont bacterium Wolbachia is currently considered the most abundant in arthropods and has also been isolated from nematodes, amphipods, isopods, mites and spiders. Recently, Wolbachia-based research was focused on the control of disease vector-population, such as several mosquitoes such as genus Aedes and Anopheles which cause dengue fever and malaria, respectively. For the analysis of regional difference between vector mosquito Aedes albopictus and Wolbachia, we selected different regions and collected Ae. albopictus which were distinguished with mountain chain and waterway. Whole genomic DNA were extracted from collected specimens with 9 regions. PCR analysis and sequencing were accomplished in each specimen for Wolbachia detection and identification using WSP gene. As a results, almost mosquitoes were infected with two strain of Wolbachia both wAlbA and wAlbB. However, regional separation of vector mosquitoes, wAlbA strain of Wolbachia were showed more than 98% sequence similarity. In this study, we first reported that Wolbachia infection and type of Wolbachia in Korea and endosymbiont Wolbachia was showed highly sequence homologies.
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