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        검색결과 45

        1.
        2023.05 구독 인증기관·개인회원 무료
        The stabilization technology for the damaged spent fuel is being developed to process the damaged fuel into sound pellet suitable for dry re-fabrication. It requires several treatments including oxidative decladding followed by reduction treatment for oxidized powder closely related to the quality of oxidized powders for pellet fabrication. For the development of operating condition for the reduction treatment, in this study, we evaluated the effect of air-cylinder based vertical shaking previously applied to oxidative decladding on powder reduction. For U3O8 of 50-100 g, the reduction test were applied with and without vertical shaking at 700°C under reduction atmosphere (Ar + 4%H2) and the concentration of hydrogen in effluent was measured to evaluate the reduction reaction. It was found that the vertical shaking system has allowed the reaction time of 50 g and 100 g U3O8 reduced by 33% compared to the test in static mode. Based on XRD analysis, the better crystallinity of the products was also achieved.
        2.
        2023.05 구독 인증기관·개인회원 무료
        The damaged spent fuel rods must be stabilized by encapsulation or dry re-fabrication technologies before geological disposal. For applying the dry re-fabrication technology, we manufactured a vertical type furnace to perform the fuel material recovery from damaged fuel rods by oxidative decladding technology. As driving forces to accelerate oxidative decladding rate, magnetic vibration and pulse hammering generated by a pneumatic cylinder were used in this study. The oxidative decladding efficiency and recovery rate of fuel oxide powder with rod-cut length, oxidation temperature and time, oxygen concentration, and gas mixtures were investigated using simfuel rod-cuts in a vertical furnace for fuel material recovery and powder quality improvement. The oxidative decladding was performed for 2.5-10 h as following operation parameters: simfuel rod-cut length of 50-200 mm, oxidative temperature from 450 to 580°C, oxygen concentration of 49.5 or 75.6%, and gas mixtures in O2/Ar or O2/N2. In magnetic vibration, oxidative decladding was progressed only at bottom portion of fuel rodcut. Whereas, oxidative decladding in pulse hammering was occurred at both top and bottom portions of fuel-rod. In pulse hammering method, the oxidative decladding conditions to declad rod-cuts of 50- 200 mm in length were established to achieve both decladding efficiency of ~100% and fuel material recovery rate of > 99%. These conditions were as follows: oxidation temperature and time at 500°C and 2.5-10 h, oxygen concentration at 75.6% under O2/N2 gas mixtures. As operation conditions for a pneumatic cylinder, stroking, actuating, and waiting times were 0.5, 3, and 12 s.
        3.
        2022.10 구독 인증기관·개인회원 무료
        Ag-containing aluminosilicate sorbents capable of capturing iodine were prepared by sol-gelation from Na, Al, and Si alkoxides using co-solvent exchange, Ag/Na ion exchange, solvent exchange, and ambient-pressure drying. The Na+AlSi-OH gel was prepared using sodium methoxide (NaOMe): aluminum tri-sec-butoxide (Al(OsBu)3): tetraethyl orthosilicate (TEOS) molar ratios of 1.05:1:1, 1.3:1.1:1, 1.5:1.3:1. The solvent effect on textural properties such as Brunauer-Emmett-Teller (BET) surface areas and pore size distributions and Ag0 particle sizes was investigated using water with high surface tension, isopropanol and n-heptane with low surface tension. The BET surface area, average pore size, and cumulative pore volume for sorbents strongly increased with decreasing surface tension of solvents and increasing Al/Si atomic ratios. In addition, Ag0 particle sizes increased with decreasing surface tension of solvents.
        4.
        2022.10 구독 인증기관·개인회원 무료
        The damaged spent fuel rods must be stabilized by encapsulation or dry re-fabrication technologies before geological disposal. For applying the dry re-fabrication technology, we manufactured a vertical type furnace to perform both fuel material recovery from damaged fuel rods by oxidative decladding and sinterability improvement of fuel powder by repetition of oxidative and reaction treatment. A horizontal type furnace provides only a diffusion-controlled reaction resulting in longer reaction time and decreasing amount of powder for oxidation and reduction, whereas a vertical type furnace with a submerged gas distributor gives rapid reaction due to flowing gas-solid contact by fluidization. For observation of fluidization behaviors of uranium oxides at room temperature, fluidized column was prepared with transparent cylindrical tube, pressure transmitter and gas flow meter. Number of size of orifice holes was determined by equations in Fluidization Engineering [D.Kunii, O. Levenspiel]. Before uranium oxide test, as surrogates, WO2 (10.8 g/cm3) and Ta2O5 (8.2 g/cm3) powder similar to density of UO2 (10.96 g/cm3) and U3O8 (8.3 g/cm3), respectively were used to achieve fluidization operation conditions in the region from minimum to expanded fluidization. Fluidization behaviors and pressure drop of powder bed was observed according to operation parameters such as gas velocity, number and size of orifice holes, and powder amount.
        10.
        2015.12 구독 인증기관 무료, 개인회원 유료
        Recently, food delivery apps are seeing rapid growth into a market worth 1 trillion won under a simple but unique business model of connecting nearby restaurants with consumers via smartphone. Though basic similarities with social commerce exists in aspects such as mail-order sales intermediaries, startups, types of services and market competition structure, food delivery apps resemble social commerce in many ways in that they use excessive marketing to secure market dominance, causing a spike in consumer complaints. If the excessive marketing and increase in customer complaints are not rectified, the food delivery app could also see rapid decline as it gradually grows distant from consumers, just like social commerce. Accordingly, this study will identify the factors consumers recognize as important for continuous use vis-a-vis social commerce and food delivery apps to perform an empirical analysis on what areas need improvement. After deriving the four upper factors of product, information system and service along with eight sub-factors by referring to existing literature, the areas with opportunity for improvement were derived through satisfaction level and relative importance evaluation. The results of this study present a strategic direction for maintaining customers of social commerce and food delivery apps.
        4,000원
        11.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Muscle satellite cell (SC) is responsible for postnatal muscle growth, repair, and regeneration. Satellite cell is an im-portant source of multi-potent stem cell process and differentiation into adipogenic, myogenic, and osteoblastogenic. The objective of this study was to identify alter of transcriptome during differentiation in porcine satellite cell and to elevated transcriptome at different stages of postnatal development to gain insight into the differences in differ-entiated PSC. We used RNA-seq technique to investigate the transcriptomes during differentiation in pig muscle. Sequence reads were obtained from Illumina HiSeq2000. Differentially expressed genes (DEG) were detected by EdgeR. Gene ontology (GO) terms are powerful tool for unification among representation genes or products. In study of GO biological terms, functional annotation clustering involved in cell cycle, apoptosis, extracellular matrix, phosphoryla- tion, proteolysis, and cell signaling in differences stage. Taken together, these results would be contributed to a better understanding of muscle biology and processes underlying differentiation. Our results suggest that the source of DEGs could be better understanding of the mechanism of muscle differentiation and transdifferentiation.
        4,500원
        12.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Satellite cells were derived from muscular tissue in postnatal pig. Satellite cell is an important to growth and development in animal tissues or organs. However, the progress underlying induced differentiation is not clear. The aim of this study was to evaluate the morphologic and the transcriptome changes in porcine satellite cell (PSC) treated with insulin, rosiglitazone, or dexamethasone respectively. PSC was obtained from postnatal muscle tissue. In study 1, for study the effect of insulin and FBS on the differentiated satellite cells, cells were cultured at absence or presence of insulin treated with FBS. Total RNA was extracted for determining the expression levels of myo-genic PAX3, PAX7, Myf5, MyoD, and myogenin genes by real-time PCR. Myogenic genes decreased expression levels of mRNA in treated with insulin. In study 2, in order to clarify the relationship between rosiglitazone and lipid in differentiated satellite cells, we further examined the effect of FBS on lipid accumulation in the presence or absence of the rosiglitazone and lipid. Significant differences were observed between rosiglitazone and lipid by FBS. The mRNA of FABP4 and PPARγ increased in rosiglitazone treatment. In study 3, we examined the effect of dexame-thasone on osteogenic differentiation in PSC. The mRNA was increased osteoblasotgenic ALP and ON genes treated with dexamethasone in 2% FBS. Dexamethasone induces osteoblastogenesis in differentiated PSC. Taken together, in differentiated PSCs, FABP4 and PPARγ increased to rosiglitazone. Whereas, no differences to FBS and lipid. These results were not comparable with previous reports. Our results suggest that adipogenic, myogenic, and osteoblasto-genic could be isolated from porcine skeletal muscle, and identify culture conditions which optimize proliferation and differentiation formation of PSC.
        4,000원
        13.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Muscular satellite cell (SC), which is stem cell of postnatal pig, is an important for study of differentiation into adipogenesis, myogenesis, and osteoblastogenesis. In this study, we isolated and examined from pig muscle tissue to determine capacity in proliferate, differentiate, and expression of various genes. Porcine satellite cells (PSC) were isolated from semimembranosus (SM) muscles of 90∼100 days old pigs according to standard conditions. The cell proliferation increased in multi-potent cell by Masson’s, oil red O, and Alizarin red staining respectively. We per-formed the expression levels of differentiation related genes using real-time PCR. We found that the differentiation into adipocyte increased expression levels of both fatty acid binding protein 4 (FABP4) and peroxisome proliferator- acti-vated receptor gamma (PPARγ) genes (p<0.01). Myocyte increased the expression levels of the myosin heavy chain (MHC), myogenic factor 5 (Myf5), myogenic regulatory factor (MyoD), and Myogenic factor 4 (myogenin) (p<0.01). Osteo-blast increased the expression levels of alkaline phosphatase (ALP) (p<0.01). Finally, porcine satellite cells were indu-ced to differentiate towards adipogenic, myogenic, and osteoblastogenic lineages. Our results suggest that muscle satellite cell in porcine may influence cell fate. Understanding the progression of PSC may lead to improved strat-egies for augmenting meat quality.
        4,000원
        15.
        2010.05 구독 인증기관·개인회원 무료
        Three acetylcholinesterases (AChEs) were identified from the pinewood nematode, Bursaphelenchus xylophilus. Sequence comparison with known AChEs in conjunction with three-dimensional structure analysis suggested that all BxAChEs share typical characteristics of AChE at the major catalytic structures. BgAChE3 was most predominantly transcribed and then followed by AChE1 and AChE2. Immunohistochemistry using anti-BxAChEs antibodies revealed that BxAChE1 is most widely distributed whereas BxAChE2 exhibits more localized distribution in neuronal tissues. BxAChE3 was detected from entire body together with some limited tissues, including mouth parts and alimentary lining, and determined to be the only soluble AChE, suggesting its localization in hemolymph or/and extracellular space. Kinetic analysis of in vitro expressed BxAChEs revealed that BxAChE1 has the highest substrate specificity whereas BxAChE2 has the highest catalytic efficiency with BxAChE3 having the lowest catalytic efficiency. Interestingly, presence of BxAChE3 in the pool of BxAChEs significantly reduced the inhibition of BxAChE1 and BxAChE2 by inhibitors. Knockout of BxAChE3 by RNAi significantly increased the toxicity of nematicides, suggesting the protective role of BxAChE3 against these toxicants. Based on several features, including tissue distribution, expression level, substrate kinetics and inhibition property, it appeared that BxAChE1 is the major AChE with the function of postsynaptic transmission whereas BxAChE3 has been evolved to acquire the function of chemical defense, perhaps intrinsically against secondary toxic compounds from host pine trees, such as α-pinene and limonene. BxAChE2 appears to play a role in post-synaptic transmission in specialized neurons but its detailed physiological function still remains to be elucidated.
        17.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        18.
        1999.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        동시증류추출장치를 사용하여 분리한 Sweet계 바질(Ocimum basilicum)의 4개 품종(anise, darkopal, lettuce, sweet)의 휘발성 성분을 GC/MSD로 확인하였다 확인된 성분을 기능기별로 분류하면 alcohol 성분들이 11종, carbonyl 화합물이 6종, terpene 관련 화합물이 19종. ester 화합물이 5종으로 나타났다. 주요 화합물들은 1, 8-cineole(2.86∼5.04%), camphor(1.07∼l.87%), α-Bergamotene(2.05∼5.40%), methyl chavicol(0∼25.49%), eugenol (3.55∼13.53%) 등의 carbonyl 화합물과 linalool(28.52∼36.50%), bornyl acetate(0.48∼2.79%), methyl cinnamate(0∼23.12%)등의 alcohol과 ester류, cis-ocimene(1.15∼2.02%), β -cubebene(2.77∼4.80%), cadinene(1.08∼1.70%)등의 terpene 화합물이 주요 성분으로 확인되었다. Darkopal, lettuce, sweet 바질은 linalool(30.09∼35.50%), methyl chavicol(8.09∼25.49%)이 주요 성분으로 나타났고, Anise 바질은 linalool(28.52%), methyl cinnamate(23.12%)가 주요 성분으로 확인되었으나 바질의 주요성분으로 알려져 있는 methyl chavicol은 검출되지 않았다.
        4,000원
        19.
        2018.05 서비스 종료(열람 제한)
        Background : Spiraea prunifolia var. simpliciflora (Rosaceae) called “Brial wreath” is a deciduous latifoliate shrub that is widely distributed throughout in Northeast Asia. Phytochemical and biological investigation of S. prunifolia have led to the discovery of biologically active compounds. Pharmacological studies revealed that the extract of the root of S. prunifolia possess antioxidant, antipyretic and anti-inflammatory activities. Some chemical constituents such as sterols, phenolics, terpene and fatty acid, as well as ethanolic extracts from the roots of S. prunifolia, have previously been reported to modulate the deleterious effects of diabetes, to prevent high-fat diet-induced obesity, and to prevent cisplatin-induced nephrotoxicity. Our continuing research was carried out to search for other phytochemical constituents from the leavess of S. prunifolia. The chemical structures of compounds were determined by NMR and FAB/MS spectroscopic data interpretation. Methods and Results : Multiple-preparative liquid chromatography (MPLC) purifications were carried out on YMC LC-forte/R instrument (YMC Kyoto, Japan) equipped with YMC-Pack ODS-A columns (ODS gel : 5 ㎛, 10 ㎜ × 250 ㎜). High-performance liquid chromatography (HPLC) was performed on Agilent Technologies instrument (Aglient Tec., Santa clara, CA, USA) equipped with YMC–Pack Pro C18 columns (ODS gel : 5 ㎛, 4.6 ㎜ × 250 ㎜). Next, quantitative analysis was carried out on UPLC-QqQ/MS 3200 Q-TRAP instrument (AB SCIEX Toronto, Canada) using a ACQUITY UPLC (waters corp.) with an ACQUITY BEH C18 column (2.1 ㎜ × 100 ㎜, 1.7 ㎛). The metabolite samples was applied to preparative reversed-phase HPLC and UPLC using gradient method, solvent A [water + 0.1% formic acid (v/v)] and solvent B [acetonitrile + 0.1% formic acid (v/v)]. Conclusion : In this study, we isolated the major metabolites from the stem of Spiraea prunifolia var. simpliciflora by using MPLC and HPLC. UPLC-QqQ/MS was also used to quantify target compounds. Finally, we established methodology and performed the quantitative analysis on target compounds from the stem of Spiraea prunifolia var. simpliciflora.
        20.
        2018.05 서비스 종료(열람 제한)
        Background : Lythrum salicaria L. (LS), a herb that is found all around the world, has long been used as medicinal plant to treat inflammation, external wound bleeding, and diarrhea, while its sprouts (young leaves) can be utilized as a food material. The antioxidant and hepato-protective activities of LS have been reported in several articles. This study was conducted to compare the efficacy and cell proliferation of LS leaves according to their growth period, and to obtain information on the optimal harvesting time of LS as a food resource. Methods and results : LS leaves were collected at ten-day intervals between April 27 and June 26, 2016 in Eumseong-gun, South Korea. The LS leaves were extracted with 50% ethanol at room temperature, and seven LS extracts (LSE) were obtained. A peroxynitrite (ONOO-) scavenging assay and a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay were performed to compare the antioxidant effects of LSE, while a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed on the BV-2 cell lines to determine cell viability. The total phenol contents of LSE were quantified by using the calibration curve of tannic acid. From these assays, LSE harvested on April 27 showed the lowest value, while LSE harvested on June 6 showed the highest DPPH scavenging activity at 10 ㎍/㎖. There was no difference among the extracts in terms of their peroxynitrite scavenging activity. The extract prepared on April 27 showed the highest value in terms of BV2 cell viability, while that obtained on June 6 showed the lowest value. The value in terms of the total phenol content of the LSE harvested on June 6 was the highest, whereas that of the LSE harvested on April 27 was the lowest. Conclusion : When comparing the activity of LSE according to its harvesting time, the extract dated June 6 showed the highest effect in terms of its antioxidant activity and its total phenol content, whereas the extract dated April 27 showed the highest cell viability. As such, this study suggests that LS leaves harvested in the early season could be utilized as a food material even though they display low efficacy.
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