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        검색결과 16

        1.
        2023.11 구독 인증기관·개인회원 무료
        In nuclear power plant (NPP) decommissioning, ventilation and purification of the building atmosphere are important to create a working environment, ensure worker safety, and prevent the release of gaseous radioactive materials into the environment. The heating, ventilation, and air conditioning (HVAC) system of each building is maintained, modified, or newly installed. In this study, based on APR1400, operation strategies were presented in case of ventilation abnormalities in the reactor containment building (RCB), where highly radioactive particles and high dust are most frequently generated during NPP decommissioning. For research, it was assumed that the entire RCB atmospheric ventilation during decommissioning would use the RCB purge system of the existing NPP and perform continuous ventilation. Additionally, it is assumed that areas where high radiation particles and high dust occur locally, such as reactor containers or internal segments, are sealed with tents and purified using a HEFA filter of a temporary portable HVAC, and a exhaust flow path is connected to the discharge duct of the existing RCB purge system. The possibility of abnormal occurrence was largely divided into two cases. First, when large amounts of uncontrolled pollutants are released into the atmosphere inside the RCB, discharge to the environment is stopped manually or automatically by a modified engineered safety function activation signal (ESFAS). Afterwards, the RCB purge system should be operated in recirculation mode to sufficiently purify the RCB atmosphere with a HEPA filter. Second, when the first train of the low volume purge system is not running due to a failure, standby train should be operated. If both low volume purge trains fail, a high volume purge system is used. Intermittent purge operation is preferred due to large capacity during high volume purge operation. In cases where it is not possible to operate all purge systems due to common issues such as power supply, atmospheric sampling is performed to determine whether to proceed with the work inside RCB.
        2.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Norflurazon is widely used on agricultural lands and has a high potential to pollute water sources. However, its effects on fish have not been fully elucidated. The purpose of our study was to determine whether norflurazon adversely affects the developmental stage of zebrafish, which are frequently used as a model system to evaluate the environmental impact of pollutants. Norflurazon interfered with the hatching of zebrafish embryos and induced several sublethal deformities including body length reduction, increased yolk sac volume, and enlargement of the pericardial region. We further examined the cardiotoxicity of norflurazon in the flk1:eGFP transgenic zebrafish line. The vascular network, mainly in the brain region, was significantly disrupted in norflurazon-exposed zebrafish. In addition, due to the failure of cardiac looping, norflurazon-exposed zebrafish had an abnormal cardiac structure. These developmental abnormalities were related to the apoptotic process triggered by norflurazon. Overall, the present study demonstrated the non-target toxicity of norflurazon by analyzing the hazardous effects of norflurazon on developing zebrafish.
        4,000원
        3.
        2021.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to determine whether the layout of wheelhouse and work environment of coastal improved stow net fishing boats affect the physical abnormalities of wheelhouse workers through a survey and to use it as basic data to improve the wheelhouse work environment. The analysis results are as follows. The result of factor analysis on the wheelhouse work environment was classified into three factors: suitability of work environment, suitability of work space arrangement, and layout of navigational and fishing equipment. The result of factor analysis on physical abnormalities was divided into two factors: physical pain and fatigue. The results of regression model analysis showing factors affecting physical pain showed that the t-value in the regression model was 3.625 (p < 0.05), indicating that the work environment suitability had an effect on the physical pain. Work environment suitability had a significantly positive effect on the physical pain. As work environment suitability increased by 1, the physical pain increased by 0.371 (p < 0.05). The results of regression model analysis showing the influencing factors on fatigue were found to have a t-value of 3.009 (p < 0.05) in the regression model, indicating that the work environment suitability had a significantly positive effect on the feeling of fatigue. It was found that fatigue increased by 0.324 (p < 0.05) as the work environment suitability increased by 1. In addition, the manageability of task suitability was found to be t = –2.521 (p > 0.05). As the manageability of task suitability increased, the skipper’s fatigue level decreased. From these results, it is inferred that the wheelhouse of the current coastal improved stow net fishing boats causes physical pain and fatigue for the skippers. In order to reduce such physical pain and fatigue, and to improve safe fishing operation and job satisfaction, it is necessary to provide a wheelhouse to fishermen on coastal improved stow net fishing boats in consideration of the characteristics of the wheelhouse work of fishing boats and in consideration of users.
        4,200원
        4.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적: 약시의 시감각 이상 위한 임상에서 가능한 검사를 확인하고자 하였다. 대상 및 방법: 정상안 24명(15.6±6.1(세))과 약시 치료 중이거나 중단한 약시안 21명(11.4±4.4(세))을 대 상으로, 시감각 검사법들 중 원-근거리 시력, 단안-양안 조절력, MEM을 이용한 조절래그, 입체시 검사를 실시하여 비교 분석하였다. 또한, 약시 그룹을 부등시성(굴절성)과 혼합성(사시성) 약시로 나누어 시감각의 차이를 비교하였다. 결 과: 정상안과 약시안의 시감각 비교에서 원거리 시력(정상안: 1.0±0.0, 약시안: 0.53±0.3), 근거리 시력(0.99±0.03, 0.43±0.25), 조절래그(0.78±0.25, 0.63±0.51(D))와 입체시(32.71±6.90, 457.62±320.47(sec of arc))에서 통계적으로 유의한 차이(p<0.05)를 보여 시감각 검사방법 중 네 가지 방 법으로 약시안의 시감각 이상을 확인 할 수 있었다. 하지만, 단안-양안 조절력과 굴절성과 사시성 약시 그 룹간의 시감각 이상 비교에서는 큰 차이를 보이지 않았다. 결 론: 원-근거리 시력, 조절래그 그리고 입체시 검사들이 약시의 시감각 이상의 정도를 파악할 수 있다 는 결과를 보였으며, 약시의 종류로서의 시감각 검사는 적합하지 않았다. 그러므로, 약시의 치료 및 분석에 있어서 이 연구에서 제시한 방법을 통해 보다 다각적인 약시의 임상적인 접근이 가능할 것으로 보인다.
        4,000원
        5.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        인구의 약 3퍼센트를 차지하는 약시는 시로에 병리학적 이상 없이 시력의 발달성 저하로 정의할 수 있다. 적절한 시자극이 없으면, 신경 가소성 기간 동안 시각계는 계속적으로 약시로 발전한다. 약시의 시감각은 시 력, 대비감도의 저하와 공간 왜곡이 비정상적일 뿐만 아니라 추적과 추종 운동과 같은 눈 움직임에도 이상을 보인다. 그러므로, 약시 치료에서 최종결과에 영향을 미치는 요소들에 따라 가장 효과적인 방법이 적용되어 야 한다.
        4,500원
        6.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oil spills have occurred throughout the years of industrialization and represent a global challenge as they affect vast areas of the ocean. The toxicity of crude oil to aquatic organisms has been extensively investigated, but the potential impacts of crude oil on vertebrate development remain largely unknown. Here, we investigated the effects of dispersants used in treating a recent oil spill, as well as that of crude oil, on vertebrates by using the zebrafish (Danio rerio) model species, which has been widely used in empirical studies of both early embryonic development and adult physiology. Chronic exposure to crude oil resulted in marked developmental abnormalities, including pericardial edema, abnormal trunk vessel development, retardation of axonal branching, and abnormal jaw development. Embryonic development was affected more severely by exposure to the oil-dispersant combination than to the oil alone. Thus, the zebrafish in vivo model system suggests that dispersant treatment can have detrimental developmental effects on vertebrates and its potential impact on marine life, as well as humans, should be carefully considered in clean-up efforts at the site of an oil spill.
        4,000원
        11.
        2001.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        영산강 수계의 습지생태계 모니터링의 일환으로 4개 지역을 선정하여 황소개구리 205개체를 채집하여 이들의 외부기형 출현율 및 양상을 조사하고 그들의 체내 조직에 축적된 중금속 농도를 분석하였다. 황소개구리의 기형 출현율은 6.8%로 다른 척추동물에서의 자연발생률 3%보다 높았으며, 기형은 모두 앞 또는 뒷발갉에서 나타났다. 유형별로 보면 결손(Ectrodactyly)이 64.3%로 가장 많았고 다음으로 확장(Dilation)이 28.6%, 절단(Truncation) 7.1%의 순이었다. 정상과 기형 개체간에 중금속의 농도를 조직별로 비교해 본 결과 기형개체의 신장에서 Mn은 4배, Zn 은 1.5배, Cu은 7배, Pb는 8배, Cd는 7배 정도 높았다. 또한 기형 개체에서는 이들 원소의 조직분포 패턴도 변화한 것으로 나타났다. 이러한 결과들로부터 황소개구리는 습지생태계의 모니터링 시료로서 유용하게 이용될 수 있음을 알 수 있었다.
        4,000원
        13.
        1996.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Spinal cord injury in child often occurs without evidence of fracture or dislocation. The mechanisms of neural damage in this syndrome of spinal cord injury without radiographic abnormality(SCIWORA) include flexion, hyperextension, longitudinal distraction, and ischemia. Inherent elasticity of the vertebral column in infants and young children, among other age-related anatomical peculiarities, render the pediatric spine exceedingly vulnerable to deforming forces. The neurological lesions encountered in this syndrome include a high incidence of complete and severe partial cord lesions. Children younger than 8years old sustain more serious neurological damage and suffer a larger number of upper cervical cord lesions than children aged over 8 years. Of the children with SCIWORA. 52% have delayed onset of paralysis up to 4 days after injury, and most of these children recall transient paresthesia, numbness, or subjective paralysis. The long-term prognosis in cases of SCIWORA is grim. Most children with complete and severe lesions do not recover; only those with initially mild neural injuries make satisfactory neurological recovery.
        4,000원
        14.
        2015.09 서비스 종료(열람 제한)
        DGCR8 is a RNA-binding protein working with DROSHA to produce pre-microRNA in the nucleus, while DICER does not only mature microRNA but also endogenous siRNAs in the cytoplasm. Here, we have produced Dgcr8 conditional knock-out mice using progesterone receptor (PR)-Cre (Dgcr8flox/flox; PRcre/+ mice, Dgcr8d/d) and demonstrated that canonical microRNAs dependent of DROSHA-DGCR8 complex are required for uterine development as well as female fertility in mice. Adult Dgcr8d/d females did not undergo regular reproductive cycle and produce any pups when housed with fertile males, whereas administration of exogenous gonadotropins induced normal ovulation with corpus luteal formation in these mice. Ovulated oocytes from Dgcr8d/d mice had comparable fertilization potentials and were normally developed to the blastocyst after fertilization as compared to those in control Dgcr8f/f mice. Interestingly, PR-Cre-dependent Dgcr8 deletion showed aberrant infiltration of acute inflammatory immune cells to female reproductive organs only when Dgcr8d/d mice were mated with male mice. With respect to uterine development, gross morphology, histology, and weight of Dgcr8d/d uterus were similar to those of control at 3-week-old age. However, multiple uterine abnormalities were noticeable at 4-week-old age when PR expression is significantly increased, and these deformities became severe onwards. Gland formation and myometrial layers were significantly reduced, and stromal cell compartment did not expand and became atrophic during uterine development in these mice. These results were consistent with aberrantly reduced cell proliferation in stromal cell compartments of Dgcr8d/d mice. Collectively, our results suggest that DGCR8 dependent-canonical microRNAs are essential for development and physiology of the uterus with respect to morphogenesis, proper immune modulation, reproductive cycle, and steroid hormone responsiveness in mice.
        15.
        2003.09 서비스 종료(열람 제한)
        Since it was first reported in 1997, somatic cell cloning has been demonstrated in several other mammalian species. On the mouse, it can be cloned from embryonic stem (ES) cells, fetus-derived cells, and adult-derived cells, both male and female. While cloning efficiencies range from 0 to 20%, rates of just 1-2% are typical (i.e. one or two live offspring per one hundred initial embryos). Recently, abnormalities in mice cloned from somatic cells have been reported, such as abnormal gene expression in embryo (Boiani et al., 2001, Bortvin et al., 2003), abnormal placenta (Wakayama and Yanagimachi 1999), obesity (Tamashiro et ai, 2000, 2002) or early death (Ogonuki et al., 2002). Such abnormalities notwithstanding, success in generating cloned offspring has opened new avenues of investigation and provides a valuable tool that basic research scientists have employed to study complex processes such as genomic reprogramming, imprinting and embryonic development. On the other hand, mouse ES cell lines can also be generated from adult somatic cells via nuclear transfer. These 'ntES cells' are capable of differentiation into an extensive variety of cell types in vitro, as well assperm and oocytes in vivo. Interestingly, the establish rate of ntES cell line from cloned blastocyst is much higher than the success rate of cloned mouse. It is also possible to make cloned mice from ntES cell nuclei as donor, but this serial nuclear transfer method could not improved the cloning efficiency. Might be ntES cell has both character between ES cell and somatic cell. A number of potential agricultural and clinical applications are also are being explored, including the reproductive cloning of farm animals and therapeutic cloning for human cell, tissue, and organ replacement. This talk seeks to describe both the relationship between nucleus donor cell type and cloning success rate, and methods for establishing ntES cell lines. (중략)