• Molecular & Cellular Toxicology
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• v.1 no.4
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• pp.268-274
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• 2005

Bromobenzene (BB) is well known hepatotoxicant. Also, BB is an industrial solvent that arouses toxicity predominantly in the liver where it causes centrilobular necrosis. BB is subjected to Cytochrome P450 mediated epoxidation followed by either conjugation with glutathione, enzymatic hydrolysis or further oxidation. In this study, we focused on BB-induced gene expression at non-hepatotoxic dose. Mice were exposed to two levels of BB, sampled at 24 h, and hepatic gene expression levels were determined to evaluate dose dependent changes. When examining the toxic dose of BB treated group in other previous studies, genes related to heat shock protein, oxidative stress, and drug metabolism are expressed. Compared to these results, our study, in which non-toxic dose of BB was administrated, showed similar patterns as the toxic conditions above. The purpose of the study was to select genes that showed changes in relation to the differing dose through confirmation of the difference within transcriptomic boundaries, but those that are not detected by the existing classic toxicology tools in non-hepatotoxic dose.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.75-83
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• 2017

In severe accident conditions of light water reactors, the loss of coolant may cause problems in integrity of zirconium fuel cladding. Under the condition of the loss of coolant, the zirconium fuel cladding can be exposed to high temperature steam and reacted with them by producing of hydrogen, which is caused by the failure in oxidation resistance of zirconium cladding materials during the loss of coolant accident scenarios. In order to avoid these problems, we develop a multi-metallic layered composite (MMLC) fuel cladding which compromises between the neutronic advantages of zirconium-based alloys and the accident-tolerance of non-zirconium-based metallic materials. Cold pilgering process is a common tube manufacturing process, which is complex material forming operation in highly non-steady state, where the materials undergo a long series of deformation resulting in both diameter and thickness reduction. During the cold pilgering process, MMLC claddings need to reduce the outside diameter and wall thickness. However, multi-layers of the tube are expected to occur different deformation processes because each layer has different mechanical properties. To improve the utilization of the pilgering process, 3-dimensional computational analyses have been made using a finite element modeling technique. We also analyze the dimensional change, strain and stress distribution at MMLC tube by considering the behavior of rolls such as stroke rate and feed rate.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.186-192
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• 2003

The health benefits of friendly bacteria first came to the attention of the general public in 1908, when Dr. Elie Metchnikoff, a Russian biologist, wrote The Prolongation of Life. The longevity may be, in part, due to the antioxidative ability of lactic acid bacteria. However, the antioxidative effect of lactic acid bacteria has been reported only recently. Many kinds of reactive oxygen species can be formed in the human body and in food system, oxidative stress plays a significant pathological role in human disease. Antioxidants are effective for the reduction of oxidation induced by oxygen radicals by scavenging reactive oxygen species. Various synthetic and natural antioxidants have been reported, but there are doubts about the safety and long term effects on health. Antioxidants from natural sources are likely to be found more desirable. An elevated scavenging ability of reactive oxygen species would be a good property for commercially applied lactic acid bacteria. Antioxidant supplement or food containing antioxidants would be greatly applied for the reduction of oxidative damage for human body, and lactic acid bacteria are potentiated candidates for the production of functional foods or natural antioxidant supplements.

• The Korea Journal of Herbology
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• v.31 no.5
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• pp.85-92
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• 2016

Objectives： This study is experimental comparison of brown rice (BR) and germinated brown rice (GBR) on upper gastrointestinal diseases animal models.Methods： The ICR mice were divided randomly into four groups of six animals each (Normal mice, gastritis mice, gastritis mice treated with BR, gastritis mice treated with 48h GBR). Gastritis was induced by administration of 0.5 mL 150 mM HCl-60% ethanol. Six-week-old male Sprague-Dawley (SD) rats were randomly divided into 7 groups after 1 week adaptation. (Normal rat, reflux esophagitis (RE) rat, RE rat treated with BR, RE rat treated with 24,30,36,48h GBR). Reflux esophagitis was induced by ligation with a 2-0 silk thread both the pylorus and the transitional junction between the forestomach and the corpus in SD rats.Results： HCl/ethanol-induced gastric mucosal injury mice were ameliorated mucosal damage upon histological evaluation by treatment of 48h GBR than BR. Optical changes such as hyperemia and multiple erosions were observed in the rats with RE and damage to the normal rats was not apparent. The oral administration of GBR significantly diminished against gross mucosal damage in a germination time-dependent manner. Also, the administration of GBR suppressed the biomarker of oxidative stress, reactive oxygen species (ROS) and produces peroxynitrite (ONOO-) in serum. However, the administration of GBR could not affect to the pH level secreted from stomach when compared with Control group.Conclusions： These findings suggest that GBR could have improving effects on upper gastrointestinal diseases in a germination time-dependent manner.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3327-3332
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• 2010

We investigated the effects of newly synthesized 4-[(butylsulfinyl)methyl]-1,2-benzenediol (SMBD) on the prevention of atherosclerosis in hypercholesterolemic rabbits. SMBD exhibited stronger inhibition of $Cu^{2+}$-induced low-density lipoprotein oxidation than that of ascorbic acid or simvastatin. Three-month-old rabbits were fed an atherogenic diet containing 0.5% cholesterol and 10% coconut oil, while other two groups were given an atherogenic diet with intravenous injection of either simvastatin or SMBD (0.33 mg/kg/day) for 4 weeks. The concentrations of plasma cholesterol and thiobarbituric acid reactive substances were significantly decreased in SMBD groups, compared to the control group. Also, aortic lipid level in the SMBD group significantly lower than that in the control group. Furthermore, compared with the control group, the SMBD group significantly inhibited the increase of aortic intimal thickness by 36% via reducing of aortic reactive oxygen species and cyclooxygenase-2 protein levels. We conclude that raised antioxidant effect of SMBD results in significant prevention against hypercholesterolemia.

• Journal of Ginseng Research
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• v.33 no.4
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• pp.249-255
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• 2009

The oxidation of glycolate to glyoxylate, a key step in plant photorespiration, is carried out by the peroxisomal flavoprotein glycolate oxidase (EC 1.1.3.15). To investigate the altered gene expression and the role of GOX in ginseng plant defense system, a cDNA clone containing a GOX gene designated as PgGOX was isolated and sequenced from Panax ginseng. The cDNA was 692 nucleotides long and have an open reading frame of 552 bp with a deduced amino acid sequence of 183 residues. A GenBank BlastX search revealed that the deduced amino acid of PgGOX shares a high degree homology with the Glycine max (95% identity). In the present study we analyzed the expression of PgGOX under various environmental stresses at different times using real time-PCR. The results showed that the expressions of PgGOX increased after various treatments involving salt, light, cold, ABA, SA, and copper treatment.

• Journal of Ginseng Research
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• v.44 no.4
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• pp.527-537
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• 2020

Panax ginseng, a medicinal plant, has been used as a blood-nourishing tonic for thousands of years in Asia, including Korea and China. P. ginseng exhibits adaptogen activity that maintains homeostasis by restoring general biological functions and non-specifically enhancing the body's resistance to external stress. Several P. ginseng effects have been reported. Korean Red Ginseng, in particular, has been reported in both basic and clinical studies to possess diverse effects such as enhanced immunity, fatigue relief, memory, blood circulation, and anti-oxidation. Moreover, it also protects against menopausal symptoms, cancer, cardiac diseases, and neurological disorders. The active components found in most Korean Red Ginseng varieties are known to include ginsenosides, polysaccharides, peptides, alkaloids, polyacetylene, and phenolic compounds. In this review, the identity and bioactivity of the non-saponin components of Korean Red Ginseng discovered to date are evaluated and the components are classified into polysaccharide and nitrogen compounds (protein, peptide, amino acid, nucleic acid, and alkaloid), as well as fat-soluble components such as polyacetylene, phenols, essential oils, and phytosterols. The distinct bioactivity of Korean Red Ginseng was found to originate from both saponin and non-saponin components rather than from only one or two specific components. Therefore, it is important to consider saponin and non-saponin elements together.

• Molecules and Cells
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• v.38 no.12
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• pp.1096-1104
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• 2015

Particulate $matter_{2.5}$ ($PM_{2.5}$) is notorious for its strong toxic effects on the cardiovascular, skin, nervous, and reproduction systems. However, the molecular mechanism by which $PM_{2.5}$ aggravates disease progression is poorly understood, especially in a water-soluble state. In the current study, we investigated the putative physiological effects of aqueous $PM_{2.5}$ solution on lipoprotein metabolism. Collected $PM_{2.5}$ from Seoul, Korea was dissolved in water, and the water extract (final 3 and 30 ppm) was treated to human serum lipoproteins, macrophages, and dermal cells. $PM_{2.5}$ extract resulted in degradation and aggregation of high-density lipoprotein (HDL) as well as low-density lipoprotein (LDL); apoA-I in HDL aggregated and apo-B in LDL disappeared. $PM_{2.5}$ treatment (final 30 ppm) also induced cellular uptake of oxidized LDL (oxLDL) into macrophages, especially in the presence of fructose (final 50 mM). Uptake of oxLDL along with production of reactive oxygen species was accelerated by $PM_{2.5}$ solution in a dose-dependent manner. Further, $PM_{2.5}$ solution caused cellular senescence in human dermal fibroblast cells. Microinjection of $PM_{2.5}$ solution into zebrafish embryos induced severe mortality accompanied by impairment of skeletal development. In conclusion, water extract of $PM_{2.5}$ induced oxidative stress as a precursor to cardiovascular toxicity, skin cell senescence, and embryonic toxicity via aggregation and proteolytic degradation of serum lipoproteins.

• Korean Journal of Materials Research
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• v.21 no.11
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• pp.596-603
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• 2011

The very high temperature gas reactor (VHTR) is one of the next generation nuclear reactors for its safety, long-term stability, and proliferation-resistance. The high operating temperature of over 800$^{\circ}C$ enables various applications with high energy efficiency. Heat is transferred from the primary helium loop to the secondary helium loop through the intermediate heat exchanger (IHX). The IHX material requires creep resistance, oxidation resistance, and corrosion resistance in a helium environment at high operating temperatures. A Ni-based superalloy such as Alloy 617 is considered as a primary candidate material for the intermediate heat exchanger. In this study, the microstructures of Alloy 617 crept in pure helium and air environments at 950$^{\circ}C$ were observed. The rupture time in helium was shorter than that in air under small applied stresses. As the exposure time increased, the thickness of outer oxide layer of the specimens clearly increased but delaminated after a long creep time. The depth of the carbide-depleted zone was rather high in the specimens under high applied stress. The reason was elucidated by the comparison between the ruptured region and grip region of the samples. It is considered that decarburization caused by minor gas impurities in a helium environment caused the reduction in creep rupture time.

• Korean Journal of Materials Research
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• v.20 no.3
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• pp.125-131
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• 2010

In this study, Ti powders were fabricated from Ti scrap by the Hydrogenation-Dehydrogenation (HDH) method. The Ti powders were prepared from the spark plasma sintering (SPS) and their microstructure was investigated. Hydrogenation reactions of Ti scrap occurred at near $450^{\circ}C$ with a sudden increase in the reaction temperature and the decreasing pressure of hydrogen gas during the hydrogenation process in the furnace. The dehydrogenation process was also carried out at $750^{\circ}C$ for 2 hrs in a vacuum of $10^{-4}$ torr. After the HDH process, deoxidation treatment was carried out with the Ca (purity: 99.5%) at $700^{\circ}C$ for 2 hrs in the vacuum system. It was found that the oxidation content of Ti powder that was deoxidized with Ca showed noticeably lower values, compared to the content obtained by the HDH process. In order to fabricate the Ti compacts, Ti powder was sintered under an applied uniaxial punch pressure of 40 MPa in the range of $900-1200^{\circ}C$ for 5 min under a vacuum of $10^{-4}$ torr. The relative density of the compact was 99.5% at $1100^{\circ}C$ and the tensile strength decreased with increasing sintering temperature. After sintering, all of the Ti compacts showed brittle fracture behavior, which occurred in an elastic range with short plastic yielding up to a peak stress. Ti improved the corrosion resistance of the Ti compacts, and the Pd powders were mixed with the HDH Ti powders.