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        검색결과 22

        1.
        2023.05 구독 인증기관·개인회원 무료
        In the event of a radioactive release, it is essential to quickly detect and locate the source of the release, as well as track the movement of the plume to assess the potential impact on public health and safety. Fixed monitoring posts are limited in their ability to provide a complete picture of the radiation distribution, and the information they provide may not be available in real-time. This is why other types of monitoring systems, such as mobile monitoring, aerial monitoring, and personal dosimeters, are also used in emergency situations to complement the information provided by fixed monitoring posts. Also, the monitoring system can be improved by using the Kriging technique, which is one of the interpolation methods, to predict the radiation dose in the relevant districts. This can be achieved by utilizing both the GPS information and the radiation dose measured at a particular point. The Kriging method involves estimating the value between different measurement points by considering the distance between them. The model used GPS and radiation data that were measured around the Hanbit NPP. The data were collected using a radiation measuring detector on a bus that traveled around the NPP area at 2-second intervals for one day. From the collected data, 200 data points were randomly selected for analysis, excluding the data measured at the bus garage out of a total of 16,550 data points. The average dose of the daily measurement data was 117.94 nSv/h, and the average dose of the 200 randomly extracted data was 119.17 nSv/h. The GPS and radiation dose data were utilized to predict the radiation dose around the Yeonggwang area where the Hanbit NPP is located. In the event of an abnormal release of radioactive material, it can be difficult to accurately determine the dose unless a monitoring measurement point is present. This can delay the rapid evacuation of residents during an emergency situation. By utilizing the Kriging model to make predictions, it is anticipated that more accurate dose predictions can be generated, particularly during accident scenarios. This can aid in the development of appropriate resident protection measures.
        2.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this experiment was to investigate the effect of drip irrigation volume on tomatoes (Solanum lycopersicum L.) grown in a greenhouse using perlite medium. Plants were treated by three different irrigation treatment I0, I25, and I50 (where irrigation volume of I25 and I50 was 25% and 50% higher than I0, having limited or no leaching). Growth characteristics of plants, yield and water use efficiency were measured. The result showed that plant height, leaf length and leaf width were lowest in the I0 treated plants. However, these parameters were not statistically significant differences between the plants that were grown in the I25 and I50 treatment. Soluble solids content, acidity and dry matter of 111th, 132nd, and 143rd days harvested tomato were higher in the plants irrigated with lowest volume (I0) than the higher volume (I25 or I50). In addition, water content was lower in the 111th and 132nd days of harvested tomatoes from the I0 treatment. The number of big-size tomatoes (>180 g) was significantly higher in the I25 irrigated plants. There was no significant difference in the total number of harvested fruits among the treatments. The average fruit weight and total yield of harvested tomatoes were lowest in the I0 treated plants. The water consumption of tomato was not significantly different amongst the treatments but water use efficiency was lowest in the I0 treatment. Principal component analysis revealed that total soluble solid and acidity of tomato showed a positive correlation between each other. These results suggest that I25 was the optimum irrigation treatment for tomato based on its measured growth characteristics, yield and water use efficiency.
        4,200원
        6.
        2018.05 구독 인증기관·개인회원 무료
        Composite pavements are constructed by placing a high functional asphalt surface layer on a high performance concrete rigid base layer and provide a more durable, high functional surface to road users. Service life of composite pavements is dependent on the bonding performance of the lower rigid base and the flexible surface layer. Accordingly, it is necessary to place an impermeability layer between the functional surface layer and the rigid base to enhance bonding performance and to prevent moisture penetration into the rigid base and deterioration of pavement. In order to use optimal composite pavement sections, two types were applied to impermeability layer: highly impermeable water-tight SMA and mastic asphalt currently in use. APT (Accelerated Pavement Testing) and experimental construction were carried out to evaluate bond strengths between the rigid base and the impermeability layer depending on the type of impermeability layers. Composite pavement sections for the APT had a 22 cm concrete rigid base layer and a 5cm functional surface, as well as either 5cm of SMA impermeability layer and 5cm of mastic layer. After applying around 8,574,000 ESALs, pull-off test was conducted, which showed that the mastic section outperformed the SMA section. In the experimental construction, three types of rigid base layers, JCP (Jointed Concrete Pavement), CRCP (Continuously Reinforced Concrete Pavement), and RCCP (Roller Compacted Concrete Pavement), were used for composite pavement sections, and as in the APT, two types of impermeability layers, SMA and mastic, were used per rigid base layer of new and deteriorated concrete pavement. Therefore, seven composite pavement sections in total were constructed. We measured the bond strength over one year or so following the construction of these composite pavement sections and found that regardless of the type of rigid base layer and whether it was new or not, those sections with a mastic impermeability layer had high bond strengths.
        8.
        2012.06 구독 인증기관·개인회원 무료
        Polycystic ovarian syndrome (PCOS) is a heterogeneous syndrome associated with follicle growth arrest, dysregulated sex hormone profile, hyperthecosis and insulin resistance. Chemerin, a novel adipokine, is associated with obesity and metabolic syndrome. Although obese women and in PCOS subjects have elevated plasma chemerin levels, whether and how chemerin is involved in the regulation of follicular growth/steroidogenesis and pathogenesis of PCOS is unknown. Our objective is to better understand the complex regulatory mechanisms involved in the control of these processes and gain insights in their dysregulation in the pathogenesis of PCOS. We hypothesize that: (a) hyperandrogenism induces small and medium antral follicle growth arrest and ovarian structural changes, resulting from granulosa cell and oocyte apoptosis and theca cell survival, and (b) chemerin regulates follicular growth and steroidogenesis and contributes to the pathogenesis of PCOS. Using immature rats (day 13~15 for follicle culture and day 21~24 for granulosa cells culture) and a chronically androgenized rat model [dihydrotestosterone (DHT); 83 μg daily, day 21~105] which recapitulates the reproductive and metabolic phenotypes of human PCOS, we have examined the granulosa cell expression patterns of chemerin and its receptor CMKLR1 and their steroidogenic and follicle growth capability. DHT treatment resulted in decreased follicle numbers in preantral to preovulatory stages and absence of corpus luteum, but increased numbers of condensed atypical follicles. Atypical follicles, constituted predominantly of theca cells, exhibited high expression of calpain and down‐regulation of the cytoskeletal protein substrates vimentin, fodrin and β‐tubulin. Granulosa cell aromatase expression was significantly down‐regulated, a response accompanied by increased activated caspase‐3 content and DNA fragmentation. While PTEN levels were considerably higher in granulosa cells in the PCOS rats than controls, phospho‐Akt (Ser473) content was lower. In addition, DHT also activated granulosa cell caspase‐3, decreased XIAP, PARP and phospho‐Akt contents and induced apoptosis in vitro, responses that could be attenuated by forced expression of XIAP. These findings are consistent with our hypothesis that dysregulated follicular growth in PCOS is associated with changes in follicular growth dynamics and follicle cell fate, a consequence of dysregulated interactions of pro‐survival (p‐Akt, XIAP, PARP) and proapoptotic (calpain, PTEN, caspase‐3) modulators in a cell‐specific manner. Chemerin and CMKLR1 were expressed in granulosa cells and negatively regulated by gonadotropin in vivo and in vitro. Serum and ovarian chemerin levels in DHT‐treated rats were elevated, and associated with arrested early antral follicular growth, remodeling of the follicle wall and decreased expression of p450 side‐chain cleavage enzyme (p450- scc), aromatase and hydroxysteroid dehydrogenases. Recombinant chemerin inhibited FSH ‐ induced estradiol secretion in granulosa cells from DHT‐treated rats in vitro. Chemerin also suppressed basal and FSH‐ and GDF9‐induced follicle growth and estradiol/ progesterone production in preantral follicle cultures. Moreover, chemerin suppressed FSH‐induced p450scc/aromatase expression and progesterone/estradiol secretion in immature rat granulosa cells in vitro. These studies demonstrate that chemerin is a novel negative regulator in FSH‐induced follicular growth and steroidogenesis and support the notion that the dysregulation of chemerin expression and function contributes to pathogenesis of PCOS. Our observations also suggest that this chronically androgenized rat model may be useful not only for studies on the long term effects of androgen on folliculogenesis, but also on the pathophysiology of PCOS. * This work was supported by grants from the Canadian Institutes of Health Research (CIHR; MOP‐119381) and the World Class University (WCU) program through the Ministry of Education, Science and Technology funded by the National Research Foundation of Korea (R31‐10056).
        9.
        2010.10 구독 인증기관·개인회원 무료
        Ascotis selenaria, a major geometridae moth in citrus trees, annually damages the citrus leaves and fruits. The surface of young citrus fruit were usually fed by 1st larva of A. selenaria after landing or stepping onto the citrus fruits. To protect the larval damages of citrus fruits needs to predict the accurate occurrence time of the 1st larva for spraying. Because larval occurrences is dependent on the oviposition of adult female and the eggs were not found in/on citrus trees, oviposition model of A. selenaria linked with the egg development model will be helpful of protecting larval damages on citrus fruits. Adult longevity, survival and fecundity of A.selenaria was investigated at 13, 16, 20, 24, 28, 30, 32, and 35℃. The longevity decreased as the temperature increased and the female development rates (1/median longevity) were well described by a modified sigmoid model, which was used to calculate the adult physiological age. Description of the total fecundity was used by a non-linear model: The maximum fecundity of A. selenaria was estimated as 2490 eggs and peaked temperature was 19.7℃ according to the fecundity model. The cumulative age-specific oviposition rate and the age-specific survival rate was well described by 2 parameters Weibull function and a reverse logistic curve respectively. Total fecundity model, age-sepecific oviposition model, and age-specific survival model were incorporated into the oviposition model.
        10.
        2018.08 KCI 등재 서비스 종료(열람 제한)
        방사선작업종사자 및 방사선작업장의 위험성은 주로 피폭선량 값으로 평가되고 있다. 하지만, 방사선작업장은 사용하는 방사선 및 작업환경이 상이하다. 특히, 방사선투과검사작업장은 작업대상물, 차폐체 사용 가능 유무 등에 따라 작업환경이 다양하다. 따라서 효율적인 방사선 방호를 위해서는 여러 가지 인자들을 검토하는 것이 필요하다. 이에 전문가 및 조장 방사선작업종사자들 대상으로 설문조사를 수행하였으며, 그 결과, 방사선원, 방사선피폭선량, 작업장관리현황, 판독특이자, 정기검사현황이 주요인자로 선정되었다. 또한, 설문조사 중요도를 바탕으로 1차 가중치(안)을 설정한 후 2차적으로 전문가 자문을 통해 인자 내 세부 항목별 가중치를 선정하였다. 따라서 본 연구를 통해 선정된 주요인자를 바탕으로 하여 방사선투과검사작 업장 위해도 지수 모델 개발이 가능할 것으로 판단된다.
        11.
        2016.05 서비스 종료(열람 제한)
        Background : Cordyceps militaris has been an wonder drug to anti-aging efficacy and called the three main drugs with ginseng and deer antler from the past. Cordycepin, cordycepic acid (d-mannitol) and adenosine are known as functional ingredients in Cordyceps militaris. Among them, cordycepin, the representative component, has been reported as antimicrobial substance containing immune enhancement, anti-cancer and anti-inflammatory effects. Methods and Results : After Cordyceps militaris produced from different types of medium mixed with 10-fold volume of purified water, the mixture were extracted at 70±5℃ for a hour and that extracts re-extracted using ultrasonics wave for 30 minutes. Qualitative analysis of the index component was determined by using the Q-TOF (A quadrupole time-of-flight mass spectrometer), and quantitative analysis was performed by using HPLC (high-performance liquid chromatography) with Xselect HSS T3 column (2.1 X 100 mm, 2.5㎛, Waters, USA) and ultrapure water and acetonitrile as mobile phase A and B. Detection column temperature, injection volume and the flow rate were 35℃, 2 μL and 0.3 mL / minute respectively. The cordycepin content of Cordyceps militaris produced from medium mixed with vegetable and animal ingredients higher than single ingredient. Moreover, through a variety of analyzes by varying the type and content of the medium additives, the cordycepin in Cordyceps militaris produced from medium mixed with animal ingredients highest. Furthermore, the cordycepin content of a fruit body was higher than those of the a mycelium. Conclusion : These results provide a method for producing an high cordycepin content of Cordyceps militaris as functional food ingredient.
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