• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권1호
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• pp.1-8
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• 1998

Biomass of non-living brown seaweed Sargassum fluitans pretreated by different methods is capable of taking up more than $10\%$ (11 meq/g) of its dry weight in aluminum at a pH of 4.5. It is indicated that the biomass sequestered the aluminum in the form of polynuclear aluminum species. The fraction of $Al(OH)_3$ Precipitated in the aluminum nitrate solution without biomass at pH 4.5 increased as the Al concentration increased. Aluminum-alginate complex precipitated in the solution as alginate was partially released from the biomass. External colloidal precipitate occurring in native and protonated S. fluitans biomass sorption systems caused a significant difference in Al sorption isotherms determined by standard and desorption methods, respectively, Sodium ions added for pH adjustment were not sorbed at all in the presence of aluminum ions.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 추계학술발표회논문집(2)
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• pp.879-884
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• 1995

The results of performance assessment analyses have shown that the long-lived radionuclides such as I-129 control the potential individual dose impact to the public. I-129 is difficult-to-measure(DTM) in low-level waste because it is non-gamma emitting radionuclides and exists at extremely low concentrations in radioactive waste generated by nuclear reactors. In this study, computer modeling technique to predict release rate of I-129 is developed to provide another tools far performance assessment of land disposal facilities and characteristics of radwaste. Model suggested in this study will give conservative values of I-129 release rate far determination of radwaste characteristics. More detailed approach is implemented to account for release conditions of fuel source-nuclides. 1-131 concentration measured from reactor coolant and released fraction from tramp fuel have dominant roles in calculating release rate of I-129 with fuel defect conditions.

• 대한환경공학회지
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• 제22권7호
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• pp.1357-1364
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• 2000

본 연구는 소각 비산재의 물리 화학적 특성이 중금속의 용출 거동에 미치는 영향을 알아보고자 수행되었다. 영향인자로는 비산재의 pH, CEC, 입자크기, 연속추출방법에 의해 분류된 중금속의 존재형태 중에서 exchangeable fraction을 고려하였다. KSLT법에 의한 중금속의 용출율은 pH에 크게 의존적이고 원소에 따라 차이를 보였다. 카드뮴과 구리의 용출율은 pH가 증가함에 따라 감소한 반면, 납과 아연은 중성 또는 강알칼리성 조건에서 증가하는 것으로 나타났는데, 중금속의 용출 거동이 용해도에 의해 제한됨을 나타내 준다. CEC가 중금속의 용출율에 미치는 영향은 pH와 비슷한 것으로 나타났다. 비산재의 입자크기 중에서 $D_{10}$은 KSLT법에 의한 중금속의 용출량과 음의 상관성을 나타내었다. Exchangeable fraction의 경우는 비산재의 CEC 값이 40 meq/100g 미만인 시료는 선형관계에 있지만, 그 외의 CEC 값에서는 비선형관계를 보여주었다.

• Natural Product Sciences
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• 제5권3호
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• pp.113-120
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• 1999

Nitric oxide (NO) is a free radical synthesized from L-arginine by nitric oxide synthase (NOS). It is believed that NO is an important mediator in numerous physiological and inflammatory responses. Particularly, a large amount of NO released from the inducible nitric oxide synthase (iNOS) is mostly associated with inflammatory processes. Overproduction of NO in these processes including sepsis and autoimmune diseases can have deleterious consequences and pathophysiologic relevance. Therefore, for the discovery of new inhibitory agents against iNOS activity, we have evaluated about 100 kinds of natural products after partition into three layers (n-hexane, ethyl acetate and aqueous) from 100% methanol extracts to study inhibitory effects on iNOS activity induced by lipopolysaccharide (LPS) in RAW264.7 cells culture system. As a positive control, curcumin, which is known as an anti-tumor promoter, anti-inflammatory agent as an iNOS inhibitor, was used and showed the dose-dependent inhibitory effect $(IC_{50},\;2.5\;{\mu}g/ml)$. Among tested fractions, the n-hexane fraction of Cimicifuga heracleifolia $(IC_{50}:\;9.65\;{\mu}g/ml)$, Forsythiae fructus $(IC_{50}:\;6.36\;{\mu}g/ml)$, Saposhnikovia divaricata $(IC_{50}:\;5.92\;{\mu}g/ml)$, and the ethyl acetate fraction of Chrysanthemum sibiricum $(IC_{50}:\;2.56\;{\mu}g/ml)$, Gastrodia elata $(IC_{50}:\;3.46\;{\mu}g/ml)$, and the aqueous fraction of Dianthus chinensis $(IC_{50}:\;6.73\;{\mu}g/ml)$, Euonymus alatus $(IC_{50}:\;6.78\;{\mu}g/ml)$, Mechania urticifoloria $(IC_{50}:\;8.01\;{\mu}g/ml)$ showed strong inhibitory activity against LPS-stimulated iNOS. Especially, the ethyl acetate fraction of Chrysanthemum sibiricum $(IC_{50}:\;2.56\;{\mu}g/ml)$, which exhibited the strongest inhibition against iNOS, was fractionated with silica-gel column chromatography. These subfractions exhibited dose-dependent inhibition against iNOS activity in the range of $2.59-5.6\;{\mu}g/ml$ except for fraction No. 3, 4, 5, 6, 8, 9, and 16. Our study shows that Chrysanthemum sibiricum has the strongest inhibitory effect against iNOS activity and has similar effect to curcumin. Therefore, further studies for the identification of active principles from Chrysanthemum sibiricum and investigation for the mechanism of the inhibition of iNOS by active principles will be performed.

• Journal of Radiation Protection and Research
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• 제13권2호
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• pp.78-87
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• 1988

원전 사고시 (또는 원자력 발전소 사고시) 환경영향 평가에 중요하게 고려해야 될 핵종을 도출 제시하기 위해 WASH-1400에서 중요하게 고려하고 있는 25원소 54핵종의 노심재고량을 ORIGEN2 코드로써 계산한 후 환경으로 동일비율로 방출된다고 가정하여 급성피폭시 초기효과에 중요한 장기인 소화관, 골수, 갑상선, 허파에 대해 각 핵종에 의한 피폭선량을 평가함으로써 각각의 핵종이 초기효과에 미치는 상대적 중요도를 산출하였다. 그 결과 각 장기에 대한 초기효과에 상대적으로 중요하게 나타난 원소들은 소화관에 대해서는 Np, Ce, Ru, Y, Zr의 순으로, 골수에 대해서는 Np, I, La, Sr, Ba의 순으로, 갑상선에 대해서는 I, Te으로 요오드외원소들의 상대적중요도는 극히 미미하였고, 허파에 대해서는 Cm, Ce, Ru, Pu, Zr순으로 나타났다. 따라서 기존의 환경영향 평가시 갑상선과 전신 피폭선량에 고려되고 있는 요오드 원소와 불활성기체 외에도 원전사고 후 충분한 양이 방출될 때 인근 주민의 장기에 대한 초기효과에 크게 영향을 미치는 핵종이 많으며 이들 핵종들은 선원항 평가시 또는 사고시의 환경영향 평가시에 비중을 두고 고려해야 할 것이다.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1165-1203
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• 2024

In the paper we validate theoretical models of the pulse against experimental data from the Jozef Stefan Institute TRIGA Mark II research reactor. Data from all pulse experiments since 1991 have been collected, analysed and are publicly available. This paper summarizes the validation study, which is focused on the comparison between experimental values, theoretical predictions (Fuchs-Hansen and Nordheim-Fuchs models) and calculation using computational program Improved Pulse Model. The results show that the theoretical models predicts higher maximum power but lower total released energy, full width at half maximum and the time when the maximum power is reached is shorter, compared to Improved Pulse Model. We evaluate the uncertainties in pulse physical parameters (maximum power, total released energy and full width at half maximum) due to uncertainties in reactor physical parameters (inserted reactivity, delayed neutron fraction, prompt neutron lifetime and effective temperature reactivity coefficient of fuel). It is found that taking into account overestimated correlation of reactor physical parameters does not significantly affect the estimated uncertainties of pulse physical parameters. The relative uncertainties of pulse physical parameters decrease with increasing inserted reactivity. If all reactor physical parameters feature an uncorrelated uncertainty of 10 % the estimated total uncertainty in peak pulse power at 3 $ inserted reactivity is 59 %, where significant contributions come from uncertainties in prompt neutron lifetime and effective temperature reactivity coefficient of fuel. In addition we analyse contribution of two physical mechanisms (Doppler broadening of resonances and neutron spectrum shift) that contribute to the temperature reactivity coefficient of fuel. The Doppler effect contributes around 30 %-15 % while the rest is due to the thermal spectrum hardening for a temperature range between 300 K and 800 K.

• Nutritional Sciences
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• 제5권2호
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• pp.60-67
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• 2002

Paeonia japonica var. pilosa $N_{AKAI}$, (PJ; Baek-Jak-Yak) is a medicinal plant which has been widely used as a component or blood-building decoctions. This study was performed to investigate the immunomodulative effects of PJ in mice, using in vitro and in vivo experiments. The immunomodulative effects were studied in vitro by determining the proliferation or mice splenocytes and the production of three kinds of cytokines (IL-1$\beta$, IL-6, TNF-$\alpha$) by mire peritoneal macrophages which were cultured with sequential fractions of PJ methanol extract (methanol, hexane, chloroform, ethylacetate, butanol and water). In an in vivo experiment using mice, different concentrations of PJ water extract were orally administrated every other day for two weeks. The production of cytokines (IL-1$\beta$, IL-6, TNF-$\alpha$) secreted by activated macrophages, and the proliferation of mice splenocytes, were used as indices for immunocompetence. In vitro supplementation using a hexane fraction of PJ in the range of 1 to 100 $\mu$ g/ml enhanced splenocyte proliferation by 1.8 to 12%, and by 10-15% using an aqueous fraction, compared to the control. IL-l$\beta$ production was significantly increased with the supplementation of butanol, hexane and water extracts of PJ Higher levels of IL-6 production were detected with supplementation of chloroform or water extracts. However, there were no significant differences in the production of TNF-$\alpha$ among the treated groups and the control. From the in vivo study, the highest proliferation of splenocytes was seen in the mice orally administrated with the PJ water extract at the concentration of 500 mg/kg body weight. In the case of cytosine production, IL-1-$\beta$, IL-6, and TNF-$\alpha$ released by activated peritoneal macrophages were augmented by the oral administration of a PJ water extract. These results indicate that Pl may enhance the immune function by regulating splenocyte proliferation and cytokine production capacity in mice.

• 한국자동차공학회논문집
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• 제22권2호
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• pp.60-66
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• 2014

A control oriented model of the Lean $NO_x$ trap (LNT) was developed to determine the timing of $NO_x$ regeneration. The LNT model consists of $NO_x$ storage and reduction model. Once $NO_x$ is stored ($NO_x$ storage model), at the right timing $NO_x$ should be released and then reduced ($NO_x$ reduction model) with reductants on the catalyst active sites, called regeneration. The $NO_x$ storage model simulates the degree of stored $NO_x$ in the LNT. It is structured by an instantaneous $NO_x$ storage efficiency and the $NO_x$ storage capacity model. The $NO_x$ storge capacity model was modeled to have a Gaussian distribution with a function of exhaust gas temperature. $NO_x$ release and reduction reactions for the $NO_x$ reduction model were modeled as Arrhenius equations. The parameter identification was optimally performed by the data of the bench flow reactor test results at space velocity 50,000/hr, 80,000/hr, and temperature of $250-500^{\circ}C$. The LNT model state, storage fraction indicates the degree of stored $NO_x$ in the LNT and thus, the timing of the regeneration can be determined based on it. For practical purpose, this model will be verified more completely by engine test data which simulate the NEDC transient mode.

• 한국식품과학회지
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• 제16권1호
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• pp.41-46
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• 1984

Aspergillus niger sherumanni IAM 2059가 분비하는 펙틴질분해효소 중에서 endo-polygalacturonase 를 Sephadex G-100, DEAE-Sephadex A-50을 이용하여 분리하고 점도감소와 분해산물분석을 통해 효소의 특성을 조사하였다. Chromatography를 통해 얻은 3 개의 역가 fraction (F-A, F-I 및 F-II) 은 각각 exo형 효소, eodo-polygalacturonase, endo-polymethylgalacturonase 이었다. endo-polygalacturonase의 역가 최적 pH는 환원당 생성으로는 pH4.2 근방이었고 점도감도로는 pH4.7 근방이었다. 이 효소의 Z-value는 $7.5^{\circ}C$이고 $D40^{\circ}C$는 240sec 이며 $40^{\circ}C$에서 활성화엔트로피(Enthalphy of activation) 217.3KJ/mol, 활성화엔트로피(Entropy of activation) 409.2J/mol.K, 활성화자유에너지(Free energy activation) 89.2KJ/mol 이었다.

• 대한본초학회지
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• 제23권3호
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• pp.73-83
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• 2008

Objectives : The root of Zingiber officinale ROSC. (Zingiberis Rhizoma Recens; Ginger) has been widely used as one of folk remedies and food materials in many traditional preparations. Ginger is known as an effective appetite enhancer and anti-inflammatory agent. This study was performed to investigate the effect of ginger chloroform fraction (GCF) in microglia which play a central role on brain inflammation in neurodegenerative diseases. Methods : Dried ginger was extracted with 80% methanol, and then fractionated with chloroform. BV2 mouse microglial cells were cultured with different concentrations of GCF and then stimulated with LPS (1 ${\mu}g/m{\ell}$) at indicated times. The cell toxicity of GCF was determined by MTT assay. The concentrations of NO, PGE2 and cytokines were measured by Griess assay and enzyme-linked immunosorbant assay. The mRNA and protein expressions of iNOS, COX-2 and cytokines were determined by RT-PCR and Western blotting. The phosphorylation of three MAPKs (p38 MAPK, ERK1/2 and JNK) and $NF-{\kappa}B$ activation were determined by Western blotting. Results : GCF significantly inhibited LPS-induced production of inflammatory mediators, NO, $PGE_2$ and proinflammatory cytokines ($TNF-{\alpha}$ and $IL-1{\beta}$) in a dose-dependent manner. GCF attenuated LPS-induced expression of mRNA and protein of inflammatory enzymes, iNOS, COX-2 and proinflammatory cytokines through suppressing the phosphorylation of ERK1/2 and p38 MAPK and the activation of p65 $NF-{\kappa}B$ in BV2 cells. Conclusions : This study suggests that GCF may have an anti-inflammatory property through suppressing the inflammatory mediator production released by activated microglia after the brain injury.