• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.311-318
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• 2006

Ionizing radiation is a both a natural and man-made phenomena that plays a major role in contemporary applications. The detection of this radiation has evolved over the past several decades from simple observations to precise measurements in space, time, and energy, even in harsh environmental conditions. Tn this paper, we present a snapshot of the current state-of-the-art in radiation measurement technology, highlighting the major applications and detector developments.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1339-1348
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• 2018

The aim of this paper is to determine neutronic performances of the light water reactor (LWR) spent fuel mixed with fertile thorium fuel in a FFHR. Time dependent three dimensional calculations for major technical data, such as blanket energy multiplication, tritium breeding ratio, cumulative fissile fuel enrichment and burnup have been performed by using Monte Carlo Neutron-Particle Transport code MCNP5 1.4, coupled with a novel interface code MCNPAS, which is developed by our research group. A self-sustaining tritium breeding ratio (TBR>1.05) has been kept throughout the calculations. The study has shown that the fissile fuel quality will be improved in the course of the transmutation of the LWR spent in the FFHR. The latter has gained the reusable fuel enrichment level conventional LWRs between one and two years. Furthermore, LWR spent fuel - thorium mixture provides higher burn-up values than in light water reactors.

• Journal of Environmental Science International
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• v.14 no.6
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• pp.613-619
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• 2005

Recently, we are suffered enormous loss from a natural disaster and making an effort to prepare measures for dealing with disasters. This study shows the major causes of natural disasters and stricken area with the analysis of meteorological data based on the Korean Meteorological Administration and the Central Disaster Relief Center records during 1987-2003 and classifies natural disasters according to the causes and damaged conditions. In this study, the most damaged area were Gangwon, Gyeongnam and Gyeongi province as a result of a typhoon and a localized heavy rain. To establish an effective disaster measure for these area, detailed prevention plans should be established by its causes after investigating precise regional damage data analysis.

• BMB Reports
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• v.34 no.1
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• pp.43-46
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• 2001

$\alpha$-Phenyl-N-t-butylnitrone (PBN) is one of the most widely used spin-trapping compounds for investigating the existence of free radicals in biological systems. Recently, there has been considerable interest in the antioxidant nature of PBN on degenerative diseases, presumably related to oxidative stress. In the present study, the protective effect of PBN on the HepG2 cell line under oxidative stress was investigated. When the HepG2 cells were exposed to oxidant, such as hydrogen peroxide, menadione, or ethanol, the protective role of PBN was manifested as a reduction in trypan blue uptake and a decrease in the endogenous production of oxidants, as measured by the oxidation of 2',7'-dichlorodihydrofluorescin. The modulation of activity of major antioxidant enzymes, such as superoxide dismutase and catalase, was not significantly different either in the presence or in the absence of PBN. This indicates that PBN acts as a direct scavenger of reactive oxygen species.

• BMB Reports
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• v.33 no.3
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• pp.242-248
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• 2000

Phage display of proteins is a powerful tool for protein engineering since a vast library of sequences can be rapidly screened for a specific property. In this study, we develop da new phage display vector that was derived from a pET-25b(+) vector. The pET-25b(+) was modified in order that the expressed protein would have a T7-tag at the amino terminus and GpS (a major coat protein of M13 phage) at the carboxyl terminus. Another vector without the gp8 gene was also constructed. The newly developed phagemid vectors have several advantageous features. First, it is easy to examine whether or not the target proteins are functional and faithfully transported into the periplasmic space. This feature is due to the fact that recombinant proteins are produced abundantly in the pET system. Second, the T7-tag makes it possible to detect any target proteins that are displayed on the surface of filamentous bacteriophage. To verify the utility of the vector, the clones containing the glutathione S-transferase (GST) gene as a target were examined. The result showed that the GST produced from the recombinant vector was successfully transported into the periplasmic space and had the anticipated enzyme activity. Western blot analysis using a T7-tag antibody also showed the presence of the target protein displayed on the surface of the phage. The phages prepared from the recombinant clones were able to bind to glutathione-Sepharose and then eluted with glutathione. These results showed that the new vectors developed in this study are useful for the phage display of proteins.

• Journal of Life Science
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• v.14 no.1
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• pp.17-20
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• 2004

Effects of monovalent cations were examined on the fast $\beta$reaction of $\alpha$D56N and $\alpha$D56G mutant tryptophan synthase. Reaction rates for the production and degradation of intermediates in the reaction were changed in the presence of cathons. The mutant proteins showed different reaction rates from those of wild-type protein, and additional changes occurred in the presence of cations. The results showed that monovalent cations and $\alpha$D56 are important in allosteric properties of this protein.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.E
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• pp.1-18
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• 1996

In this review, the significance of terrestrial ecosystems in the global sulfur budget has been reviewed based on the currently available databases covering the topic. In the section 1, we describe our current understanding of natural sulfur cycle in relation to most well-known natural reservoir, oceanic environment. The sections 2 and 3 provide the fundamental pictures of the rerrestrial sulfur cycle with respect to the relative importance of its individe the fundamental pictures of the terrestrial sulfur cycle with respect to the section 3, previously reported flux values for several major sulfur gases are presented for each reservoir and are intercompared to derive representative fluxes for the respective environment. In the section 4, source mechanisms for volatile sulfur species are dealt for both microscale and macroscale processes leading to their productions. In the section 5, environmental factors controlling the exchange of biogenic sulfur gases across the air-surface have been discussed. In the section 6, environmental fate of sulfur gases released into the atmosphere has been described. Finally in tie section 7, as concluding remarksm we discuss directions and suggestions to overcome various limitations encountered from previous measurement investigations of natural sulfur cycle in diverse natural ecological systems.

• Nutritional Sciences
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• v.9 no.2
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• pp.97-105
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• 2006

Beans are well known to be high-protein diets. Bean seeds contain arginine, lysine, or glycine-rich proteins which are effective to maintain lower glucose levels. In this study, the synergistic effect of fermented small soybean (Chounggukjang) and mulberry leaf on metabolism and hexokinase activity was investigated in streptozotocin (STZ)-induced diabetic rats. We divided 8 groups as follows: non-diabetic rat group fed with only water diet (NC: control), and STZ-induced diabetic rat groups fed with water (DC), fermented Rhynchosia Nulubilis (Bbc), fermented Glycine max Merr (Ybc), Bbc and YBc (BYbc), mulberry leaf and Bbc (MBbc), mulberry leaf and Ybc (MYbc), or the mulberry leaf, Bbc, and Ybc (MBYbc). Diabetes mellitus was induced in rats by subcutaneous STZ administration (70 mg/kg of body weight). All diet groups were fed with Chounggukjang in a powder form. Three ml of Chounggukjang solution (0.75 mg per gram of body weight) dissolved in distilled water was orally administered to all rat groups after STZ administration except for NC rat group. In groups fed with fermented soybeans, the body weight (increased), food efficiency ratio (FER) (increased), glucose level (decreased) and hexokinase (HK) activity (increased) significantly differed to NC. Among them, particularly in the groups fed with both fermented soybeans and mulberry leaf, kidney weight significantly decreased, whereas HK activity significantly increased compared to DC. These results suggest that Chounggukjang of both fermented soybeans and mulberry leaf is potentially used as an effective functional food to prevent diabetes complications.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.242-246
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• 1997

The protein profile of Synechococcus sp. cyanophage was investigated employing SDS-PAGE. The phage appears to be composed of two major proteins of 97 and 52 kDa and at least seven minor proteins of 70, 65, 60, 40, 35, 28, and 6 kDa. It seems that each subunit is combined to form a multimer although any disulfide bond does not exist in the phage structure. Lytic activity of the phage particle against cell wall was detected around the 52 kDa on renaturing SDS-PAGE using heat-killed Micrococcus luteus cells as substrate. The activity has the optimal pH between 9 and 10, and slightly inhibited by EDTA.

• Journal of Life Science
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• v.32 no.12
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• pp.919-928
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• 2022

As seen in the COVID-19 pandemic, unexpected emergence of new viruses presents serious concern on public health. Especially, the absence of effective vaccines or antiviral drugs against emerging viruses significantly increases the severity of disease and duration of viral circulation among population. Natural products have served as a major source for safe and effective antiviral drugs. In this study, we examined the virucidal activity of medical herb extracts with a view to discover novel antiviral agents with desired levels of safety and antiviral efficacy. Ethanol extracts of ten selected medical herbs were tested for antioxidant activity and in-vitro cytotoxicity in various animal cell lines. Of note, the herbal extracts showed broad and potent virucidal activities against rotavirus, hepatitis A virus, and influenza A virus. The extracts of Sorbus commixta and Glycyrrhiza uralensis showed strong virucidal activities against influenza A virus. We also examined whether the extracts of Sorbus commixta and Glycyrrhiza uralensis can be used as inactivating agents to prepare an inactivated viral vaccine. In a mouse model, influenza A virus inactivated by the extracts elicited high levels of neutralizing antibodies, and the vaccination provided complete protection against lethal challenge. These results suggest that herb-derived natural products can be developed to antiviral drugs as well as inactivating agents for preparation of inactivated viral vaccines.