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        검색결과 27

        1.
        2023.11 구독 인증기관·개인회원 무료
        When the parent radionuclide decays, the progeny radionuclide is produced. Accordingly, the dose contribution of the progeny radionuclide should be considered when assessing dose. For this purpose, European Commission (EC) and International Atomic Energy Agency (IAEA) provide weighting factors for dose coefficient. However, these weighting factors have a limitation that does not reflect the latest nuclide data. Therefore, in this study, we analyzed the EC and IAEA methodology for derivation of weighting factor and used the latest nuclide data from ICRP 107 to derive weighting factors for dose coefficient. Weighting factor calculation is carried out through 1) selection of nuclide, 2) setting of evaluation period, and 3) derivation based on ICRP 107 radionuclide data. Firstly, in order to derive the weighting factor, we need to select the radionuclides whose dose contribution should be considered. If the half-life of progeny radionuclides sufficiently short compared to the parent radionuclide to achieve radioactive equilibrium, or if the dose coefficient is greater of similar to that of the parent radionuclide and cannot be ignored, the dose contribution of the progeny radionuclide should be considered. In order not to underestimate the dose contribution of progeny radionuclides, the weighting factors for the progeny nuclides are taken as the maximum activity ratio that the respective progeny radionuclides will reach during a time span of 100 years. Finally, the weighting factor can be derived by considering the radioactivity ratio and branch fraction. In order to calculate the weighting factor, decay data such as the half-life of the radionuclide, decay chain, and branch fraction are required. In this study, radionuclide data from ICRP 107 was used. As a result of the evaluation, for most radionuclides, the weighting factors were derived similarly to the existing EC and IAEA weighting factors. However, for some nuclides, the weighting factors were significantly different from EC and IAEA. This is judged to be a difference in the half-life and branch fraction of the radionuclide. For example, in the case of 95Zr, the weighting factor for 95mNb showed a 35.8% difference between this study and previous study. For ICRP 38, when 95Zr decays, the branch fraction for 95mNb is 6.98×10-3. In contrast, for ICRP 107, the branch fraction is 1.08×10-2, a difference of 54.7%. Therefore, the weighting factor for the dose coefficient based on ICRP 107 data may differ from existing studies depending on the half-life and decay information of the nuclide. This suggests the need for a weighting factor based on the latest nuclide data. The results of this study can be used as a basis for the consideration of dose contributions for progeny radionuclides in various dose assessments.
        2.
        2023.10 구독 인증기관·개인회원 무료
        본 연구는 주변 환경의 차이에 따른 화분매개곤충의 유입 특성을 파악하기 위하여 국립수목원 내 진화속을걷 는정원과 부추속전문전시원에 식재된 울릉산마늘의 화분매개곤충을 조사하였다. 2023년 5월 22일부터 6월 2일 까지 꽃이 70% 이상 개화하였을 때 포충망을 활용하여 8일간 곤충을 채집하였고, 각 전시원 별 식생(피도), 기후 (온도·습도·조도)를 조사하였다. 조사 결과 진화속을걷는정원에서 피도 60% 온도 26.4℃, 습도 31.5%, 조도 40953.6lx, 화분매개곤충 20과 450개체, 부추속전문전시원은 피도 90%, 온도 25.6℃, 습도 31.6%, 조도 6387lx, 화분매개곤충 15과 196개체로 나타났다. 온도와 조도가 상대적으로 높은 진화속을걷는정원이 채집된 곤충의 다양성과 방문 빈도가 높았다. 시간대별 곤충의 방문 빈도를 비교해본 결과 온도와 조도는 개체수가 증가할 때 같이 증가하는 경향을 보였으며, 습도는 반대의 경향을 보였다.
        4.
        2022.10 구독 인증기관·개인회원 무료
        Currently, low and intermediate-level radioactive wastes and spent nuclear fuels are continuously generated in Korea. For the disposal of the radioactive wastes, the transport demand is expected to increase. Prior to transportation, it is necessary to evaluate the radiation risk of transportation to confirm that is not high. In Korea, there is no transportation risk assessment code that reflects domestic characteristics. Therefore, foreign assessment codes are used. In this study, before developing the overland transportation risk assessment code that reflects domestic characteristics, we analyzed the radiation risk assessment methodology in transportation accident codes developed in other countries. RADTRAN and RISKIND codes were selected as representative overland transportation risk assessment codes. For the two codes we analyzed accident scenarios, exposure pathways, and atmospheric diffusion. In RADTRAN, the user classifies accident severity for possible accident scenarios, and the user inputs the probability for each accident severity. On the other hand, in the case of RISKIND, the accident scenarios are classified and the probabilities are determined according to the NRC modal study (LLNL, 1987) in consideration of the cask impact velocity, cask impact angle, and fire temperature. In the case of RISKIND, the accident scenarios are applied only to transportation of spent nuclear fuel, and cannot be defined for low and intermediate-level radioactive waste. However, in the case of RADTRAN, since the severity and probability of accidents are defined by user, it can be applied to low and intermediate-level radioactive wastes. As the exposure pathways considered in transportation accident, both RADTRAN and RISKIND consider external exposure (cloudshine and groundshine), and internal exposure (inhalation, resuspension inhalation and ingestion). In the case of RADTRAN, additionally, external exposure due to loss of shielding (LOS) is considered. Atmospheric diffusion calculation is essential to determine the extent to which radioactive materials are diffused. In both RADTRAN and RISKIND, atmospheric diffusion calculations are based on Gaussian diffusion model. Users must input Pasquill stability class, release height, heat release, wind speed, temperature and mixing height, etc. Additionally, RADTRAN can input weather information relatively simply by inputting only the Pasquill stability class fraction and selecting the US average weather option. This study results will be used as a basis for developing radioactive waste overland transportation risk assessment code that reflects domestic characteristics.
        10.
        2009.05 구독 인증기관·개인회원 무료
        We have determined the complete mitochondrial genome of the yellow-spotted long horned beetle, Psacothea hilaris (Coleoptera: Cerambycidae), an endangered insect species in Korea. The 15,856-bp long P. hilaris mitogenome harbors gene content typical of the animal mitogenome and a gene arrangement identical to the most common type found in insect mitogenomes. As with all other sequenced coleopteran species, the 5-bp long TAGTA motif was also detected in the intergenic space sequence located between tRNASer (UCN) and ND1 of P. hilaris. The 1,190-bp long non-coding A+T-rich region harbors an unusual series of seven identical repeat sequences of 57-bp in length and several stretches of sequences with the potential to form stem-and-loop structures. Furthermore, it contains one tRNAArg-like sequence and one tRNALys-likes equence. Phylogenetic analysis among available coleopteran mitogenomes using the concatenated amino acid sequences of PCGs appear to support the sister group relationship of the suborder Polyphaga to all remaining suborders, including Adephaga, Myxophaga, and Archostemata. Among the two available infraorders in Polyphaga, a monophyletic Cucujiformia was confirmed, with the placement of Cleroidea as the basal lineage for Cucujiformia. On the other hand, the infraorder Elateriformia was not identified as monophyletic, thereby indicating that Scirtoidea and Buprestoidea are the basal lineages for Cucujiformia and the remaining Elateriformia.
        15.
        2018.10 서비스 종료(열람 제한)
        Background : As a part of ongoing research to elucidate and characterize anti-cancer nutraceuticals, extracts from many kinds of medicinal plants were tested for their ability to cytotoxicity on cancer cells so far. Datura stramonium is one of the plants known to contain various alkaloids such as hyoscyamine, scopolamine, atropine etc. Traditionally, it has been used as an analgesic, antispasmodic, and central nervous stimulant. Leaves are also known to be effective against asthma, cough, and chronic bronchitis. In this study, cytotoxicity of extracts from D. stramonium on human cancer cell lines A549 (lung), and HepG2 (liver) were evaluated and compared. Methods and Results : The extract was diluted with DMSO in the form of 10, 50, 250, 1,000 μg/ml for final concentration series respectively. The cell viabilities were examined by MTT assay. On HepG2 cell line, extracts of D. stramonium showed dramatic dose-dependent cytotoxicity on 10, 50, 250, 1,000 ㎍/㎖ concentrations series as 88.16%, 78.55%, 55.57%, 23.06% cell viability respectively. On A549 cell line, likewise, same concentration series showed a dose-dependent cytotoxic effect as 96.49%, 96.12%, 68.54%, 20.26% cell viability respectively. On A549 cell line, there was no difference in effect between 10 ㎍/㎖ and 50 ㎍/㎖. Conclusion : Above results, high concentrations of extracts are effective on two cancer cell lines. These results are expected to be used on further studies about the anticancer activity of D. stramonium as basic data. In order to confirm the anticancer effect of D. stramonium, it is anticipated that additional tests will be required to confirm the apoptosis assay and related protein expression.
        16.
        2018.10 서비스 종료(열람 제한)
        Background : In ancient, roots of Rumex crispus, called wooi-daehwang, were used for various symptoms and diseases like cough, phlegm, bronchitis and hepatitis, caused inflammatory. As a part of ongoing research to elucidate and characterize anti-inflammatory nutraceuticals, solvent-partitioned fractions from R. crispus root were tested for their ability to suppress inflammation. In this study, NO synthesis inhibitory activity of solvent-partitioned fractions from R. crispus root on LPS-stimulated RAW264.7 mouse macrophages was evaluated. Methods and Results : The EtOH extracts were suspended in water. The aqueous layer was further partitioned in diethylether, ethylacetate and n-butanol, sequentially. RAW264.7 cells were seeded onto 96-well plates, and cells were allowed to adhere for 6 h and then were pretreated with the R. crispus root extracts for 24 h. Cellular nitric oxide (NO) production was stimulated by adding lipopolysaccharide (LPS). Absorbance was measured at 520 ㎚ by microplate reader. NO synthesis inhibitory activity potential of these fractions was evaluated by assessing NO production by LPS-stimulated RAW264.7 cells in the presence and absence of the solvent-partitioned R. crispus root fractions. NO synthesis inhibitory activity of diethylether fraction diluted in 50 ㎍/㎖, 25 ㎍/㎖, 12.5 ㎍/㎖, 6.25 ㎍/㎖, 3.125 ㎍/㎖ was 79.2%, 70.9%, 59.5%, 16.1%, and 11.8%, respectively. And NO synthesis inhibitory activity range of another fractions, EtOAc, n-BuOH and aqueous layer, were 0 - 30.2%, 0 - 20.1% and 3.8 - 22.4%, respectively. Conclusion : From the above results, it showed that diethylether fraction have strong NO synthesis inhibitory activity, it was suggested that R. crispus root have NO synthesis inhibitory effects. R. crispus root possesses anthraquinones, such as chrysophanol, parietin, and anthrones etc. According to previous studies, R. crispus semen extract has analgesic and hepatoprotective effect as anti-inflammatory, and extract of R. napalensis has cyclooxygenase (COX)-2, COX-1 inhibitory and free radical scavenging effect. Our present study has shown that R. crispus root extracts anti-inflammatory effects probably by suppressing iNOS expressions, and resulting in the inhibition of NO synthesis.
        17.
        2017.05 서비스 종료(열람 제한)
        Background : This study was carried out to investigate the cytotoxicity in 9 extracts from 8 medicinal plants, such as leaf extract of Lonicera maackii (Llm), leaf extract of Platycarya strobilacea (Lps), flower extract of Fagopyrum dibortryis (Fdf), stem extract of Physostegia virginiana (Spv), root extract of Allium senescence (Ras), aerial part extract of Allium schoenoprasum (Aas), aerial part extract of Artemisia japonica var. manshurica (Aaj), stem extract of Caryopteris incana (Sci), and leaf extract of Caryopteris incana (Lci), on human cancer cell lines. Methods and Results : Dried plant extracts were granted from National Institute of Horticultural and Herbal Sciences. The extracts of each plant were dissolved in DMSO and stored in deep freeze at –20℃. The cell viabilities were examined by MTT assay. On SK-OV-3 cell line, Lps, Aas, Sci ans Lci showed dose-dependent cytotoxic effect. On A549 cell line, almost samples show dose-dependent cytotoxic effect, but especially Aaj showed relatively high cytotoxic effect. In case of HCT-15 cell line, Llm and Aas showed relatively high cytotoxic effect. Conclusion : These results suggested that Lonicera maackii, Platycarya strobilacea, Fagopyrum dibortryis, Physostegia virginiana, Allium senescence, Allium schoenoprasum, Artemisia japonica var. manshurica, and Caryopteris incana can be utilized as potential sources of anticancer agent due to their cytotoxicity.
        18.
        2016.10 서비스 종료(열람 제한)
        Background : As a part of ongoing research to elucidate and characterize anti-inflammatory nutraceuticals, six kinds of plant extracts (aerial part of Nepeta cataria, leaves of Lonicera maackii, leaves of Platycarya strobilacea, flower of Fagopyrum dibotrys, flowers and fruits of Solanum nigrum, stem of Physostegia virginiana) were tested for their ability to suppress inflammation. The anti-inflammatory has been studied in lipopolysaccharide (LPS)-stimulated RAW264.7 cells which cells synthesized nitric oxide (NO) from L-arginine by nitric oxide synthase (NOS). In this study, NO synthesis inhibitory activity of six kinds of plant extracts on LPS-stimulated RAW 264.7 mouse macrophages was evaluated. Methods and Results : Six kinds of plant extracts were parceled out from RDA (Rural Development Administration). RAW 264.7 cells (1.5×105 cells/well) were seeded onto 96-well plates with DMEM media containing 10% FBS and 1% antibiotics. The cells were pretreated with the extracts and LPS-stimulated cells for 24 h. Cellular NO production was stimulated by adding 1 μg/mL of LPS. After incubation, Griess reagent was used to determine NO production. Absorbance was measured at 520 nm by microplate reader. NO synthesis inhibitory activity potential of these extracts was evaluated by assessing NO production by LPS-stimulated RAW 264.7 cells in the presence. As a result, inhibition rate of NO production was about 40% of L. maackii, 33% of F. dibotrys, 23% of P. strobilacea and 17% of P. virginiana. Meanwhile, there was no significant results in aerial part of N. cataria and flowers and fruits of S. nigrum. Conclusion : From the above results, we be able to confirm that leaves of L. maackii and flower of F. dibotrys appeared dose-dependent NO synthesis inhibitory activity and leaves of P. strobilacea appeared NO synthesis inhibitory activity in low-concentration. As screening NO synthesis inhibition of six extracts, they may be a good candidate for delaying the progression of human inflammatory diseases and warrants further studies.
        19.
        2014.09 서비스 종료(열람 제한)
        Idiopathic spontaneous intraperitoneal hemorrhage is a rare, often fatal condition; however, the patients present with nonspecific symptoms. Even after a comprehensive radiological examination and surgical exploration, the origin of hemorrhage often remains unclear. A 74-year-old woman with sudden abdominal pain, nausea, and vomiting was admitted to our hospital. She had no history of trauma. Computed tomography showed a huge hematoma along the small intestinal mesentery without evidence of visceral organ abnormality causing bleeding. The hematoma was completely removed by surgery and no origin of hemorrhage was detected. Herein, we report on a case of idiopathic spontaneous intraperitoneal hemorrhage.
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