• Transactions of the Korean hydrogen and new energy society
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• v.22 no.3
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• pp.292-298
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• 2011

This study examines the effects of the ambient temperature (AT), methanol feeding temperature (MFT), methanol concentration (MC) and methanol flow rate (MFR) on the performance and cell temperature (CT) of a 5-stacked direct methanol fuel cell (DMFC). The AT, MFT, MC, and MFR are varied from $-10^{\circ}C$ to $+40^{\circ}C$, $50^{\circ}C$ to $90^{\circ}C$, 0.5M to 3.0M and 11.7 mL $min^{-1}$ to 46.8 mL $min^{-1}$, respectively. The performance of the DMFC under various operating conditions is analyzed from the I-V polarization curve, and the methanol crossover is estimated by gas chromatography (GC). The performance of the DMFC improves significantly with increasing AT. The open circuit voltage (OCV) decreases with increasing MC due to the enhanced likelihood of methanol crossover. The cell performance is improved significantly when the MFR is increased from 11.7 mL $min^{-1}$ to 28.08 mL $min^{-1}$. The change in cell performance is marginal with further increases in MFR. The CT increases significantly with increasing AT. The effect of the MFT and MFR is moderate, and the effect of MC is marginal on the CT of the DMFC.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.808-817
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• 2016

In this study, we investigated the effects of pre-soaking in salt and sugar solution prior to air drying at $50^{\circ}C$ on the characteristics of dried apples. Pre-soaking solutions included single solutions of salt 2% and sugar 2%; and combined solutions of salt 2%+sugar 2% and salt 2%+sugar 5%, respectively. The effects of pre-soaking condition and drying were evaluated in terms of moisture content (MC), water activity, color, antioxidant activity determined by DPPH radical scavenging activity, shear force, microbial contents, and sensory evaluation of apple slices. The control sample without pre-soaking showed the most rapid drying rate; in addition, the single solutions showed higher MC and water activity after drying time of 120 min, as compared to combined solutions. In all samples, MC and water activity showed high correlation coefficients of 0.91 to 0.97; whereas, shear force was negatively correlated with MC and water activity. The single solution of salt 2% showed decrease in change of color, including L, a, and b values, and the number of aerobic bacteria during drying. In addition, highest antioxidant activity and values of sensory preferences were observed in the dried apple pre-soaked in single solution of salt 2%.

• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.46-54
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• 1996

This study was carried out to investigate the vacuum drying characteristics of 50mm- and 75mm- thick tree disks of some domestic softwoods for substituting the conventional hardwoods as the materials for wood crafts. Though the elapsed drying times from green to in-use moisture content(MC) were largely shortened by vacuum drying, the tree disks treated by EWS couldn't be dried to in-use MC, and so sapwood stains also were occurred severely. We suggest EWS treatment is undesirable for the species with very high sapwood portion or vacuum drying with hot water circulation heating system. Heart checks were slight, but sapwood checks, which have never been trouble in drying process of tree disks, were severe. For the reasonable explanation it is suggested MC differences between sapwood and heartwood were large and most of tree disks had already no barks before drying test. Ginkgo was vacuum-dried with very slight drying defects such as heart checks, sapwood checks. V-cracks and sapwood stains. In Korean red pine and pitch pine V-cracks were severely occurred. And it was found the special feature that most of these defected tree disks contained several V-cracks within one tree disk. It can be considered as the causes that the region of sapwood was defected by the several checks at the early drying stage because of the steep MC gradient along the radial direction, and then at the later drying stage the drying stresses due to differential shrinkage were concentrated on these brittle spots.

• Journal of Radiation Protection and Research
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• v.48 no.4
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• pp.197-203
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• 2023

Background: The thermoluminescent dosimeter (TLD) and Monte Carlo (MC) dosimetry are carried out to determine the occupational dose for personnel in the handling of ¹²⁵I seed sources. Materials and Methods: TLDs were placed in different layers of the Alderson-Rando phantom in the thyroid, lung and also eyes and skin surface. An ¹²⁵I seed source was prepared and its activity was measured using a dose calibrator and was placed at two distances of 20 and 50 cm from the Alderson-Rando phantom. In addition, the Monte Carlo N-Particle Extended (MCNPX 2.6.0) code and a computational phantom with a lattice-based geometry were used for organ dose calculations. Results and Discussion: The comparison of TLD and MC results in the thyroid and lung is consistent. Although the relative difference of MC dosimetry to TLD for the eyes was between 4% and 13% and for the skin between 19% and 23%, because of the existence of a higher uncertainty regarding TLD positioning in the eye and skin, these inaccuracies can also be acceptable. The isodose distribution was calculated in the cross-section of the head phantom when the ¹²⁵I seed was at two distances of 20 and 50 cm and it showed that the greatest dose reduction was observed for the eyes, skin, thyroid, and lungs, respectively. The results of MC dosimetry indicated that for near the head positions (distance of 20 cm) the absorbed dose rates for the eye lens, eye and skin were 78.1±2.3, 59.0±1.8, and 10.7±0.7 µGy/mCi/hr, respectively. Furthermore, we found that a 30 cm displacement for the ¹²⁵I seed reduced the eye and skin doses by at least 3- and 2-fold, respectively. Conclusion: Using a computational phantom to monitor the dose to the sensitive organs (eye and skin) for personnel involved in the handling of ¹²⁵I seed sources can be an accurate and inexpensive method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.50-56
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• 2020

Determination of the precise size at sexual maturity is very important for science-based stock assessment and fisheries resource management. In this study, two different models, (1) a visual method and (2) a gonadosomatic index (GSI) method, were employed to estimate length at sexual maturity of the small yellow croaker Larimichthys polyactis in the Yellow Sea of Korea. The visual method is a common qualitative method using visual gonadal identification. Conversely, the GSI method is a quantitative method using the GSI, which can be easily and precisely collected. We compared results from these methods to determine the best approach, and to examine the practicality of the GSI method. Logistic regression of the maturity ogive was conducted using a general linear model (GLM) with the R statistics program. Also, the bootstrapped 95% confidence intervals of all estimates were calculated. The best-fit model was the visual method (R_Mc²=0.805, AUC=0.989, L₅₀=15.1). Among models using the GSI method, the model computing GSI_ref=0.94 was the best-fit model (R_Mc²=0.792, AUC=0.989, L₅₀=15.2). There was no significant difference between the two models, evidencing the effectiveness and accuracy of the GSI method.

• Journal of Nutrition and Health
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• v.40 no.7
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• pp.606-615
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• 2007

This study was performed to investigate anti-thrombogenic, anti-inflammatory effects of n-BuOH (B) and $CH_2Cl_2$ (MC) fractions extracted from Sancho (Zanthoxylum. schinifolium) leaves in rats fed high fat diets. The experimental animal groups were consisted of eight including one 5% fat (N) and one 20% fat (H) without the test materials in diets and six H groups of feeding three levels (50, 100 and 150 mg/day) of the B and the MC fractions from Z. schinifolium, respectively. Plasma activated partial thromboplastin times and thrombin times of H group were decreased compared to the N group, but they were increased by feeding the MC fraction of 50 mg and over. Polymorphonuclear leukocyte 5#-lipo-xygenase activities and leukotriene $B_4$ contents of the H group were significantly increased compared to the N group, but they were decreased in the 100 mg and 150 mg of B fraction or the 150 mg of MC fraction fed groups. Liver cytochrome $P_{450}$, $O_2^-$, $H_2O_2$ and GSSG contents were increased by the high fat diet but decreased by feeding the B fraction or the MC fraction, while GSH content and glutathione S-transferase activity lowered by high fat diet were increased by feeding the two solvent fractions. The effects of the solvent fractions were evident at the level of 100 mg/day and over. The present results confirmed that two solvent fractions from the leaves of Z, schinifolium have enhancing effects on anti-thrombosis and anti-inflammation partly by antioxidant action and partly by direct modulation of the respective processeds. In conclusion, the n-BuOH and $CH_2Cl_2$ fractions from leaves of Z, schinifolium can be utilized as the proper ingredients of functional foods for preventing chronic degenerative disease.

• Journal of Nutrition and Health
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• v.50 no.5
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• pp.415-425
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• 2017

Purpose: Many studies have suggested that neuronal cells protect against oxidative stress-induced apoptotic cell death by polyphenolic compounds. We investigated the neuroprotective effects and the mechanism of action of Momordica charantia ethanol extract (MCE) against $H_2O_2-induced$ cell death of human neuroblastoma SK-N-MC cells. Methods: The antioxidant activity of MCE was measured by the quantity of total phenolic acid compounds (TPC), quantity of total flavonoid compounds (TFC), and 2,2-Diphenyl-1-pycrylhydrazyl (DPPH) radical scavenging activity. Cytotoxicity and cell viability were determined by CCK-8 assay. The formation of reactive oxygen species (ROS) was measured using 2,7-dichlorofluorescein diacetate (DCF-DA) assay. Antioxidant enzyme (SOD-1,2 and GPx-1) expression was determined by real-time PCR. Mitogen-activated protein kinases (MAPK) pathway and apoptosis signal expression was measured by Western blotting. Results: The TPC and TFC quantities of MCE were 28.51 mg gallic acid equivalents/extract g and 3.95 mg catechin equivalents/extract g, respectively. The $IC_{50}$ value for DPPH radical scavenging activity was $506.95{\mu}g/ml$ for MCE. Pre-treatment with MCE showed protective effects against $H_2O_2-induced$ cell death and inhibited ROS generation by oxidative stress. SOD-1,2 and GPx-1 mRNA expression was recovered by pre-treatment with MCE compared with the presence of $H_2O_2$. Pre-treatment with MCE inhibited phosphorylation of p38 and the JNK pathway and down-regulated cleaved caspase-3 and cleaved PARP by $H_2O_2$. Conclusion: The neuroprotective effects of MCE in terms of recovery of antioxidant enzyme gene expression, down-regulation of MAPK pathways, and inhibition apoptosis is associated with reduced oxidative stress in SK-N-MC cells.

• Journal of Animal Science and Technology
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• v.54 no.4
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• pp.255-265
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• 2012

The objectives of this study were to investigate MC1R genotype, coat color, and muzzle phenotype variationsin the Korean native brindle cattle (KNBC) maintaining family lines and to establish the mating system for increased brindle coat color appearance. KNBC with genotype and phenotype records were selected as experimental animals. The relationship between melanocortin 1 receptor (MC1R) genotypes, verified by PCR-RFLP, and brindle coat color appearance was determined. Fragments of the MC1R gene amplified by PCR were digested with MspI and RFLP was determined. KNBC had $E^+E^+$, $E^+e$, and ee genotypes. The $E^+e$ genotype was most common with 65%, compared to $E^+E^+$ (33.33%), or ee (1.67%). When the sire had $E^+e$ genotype and the dam had $E^+E^+$ genotype, and both of them had the whole body-brindle coat color, all of their offspring (4/4) had whole body-brindle coat color. When the sire had $E^+E^+$ genotype and the dam had $E^+e$ genotype, and both had whole body-brindle coat color, 44.44% (4/9) of the offspring had whole body-brindle coat color. The mating between the sires and dams with these two genotypes with whole body-brindle coat color may have the highest whole body-brindle coat color appearance in their offspring. Muzzle grades 3 or 4 were more common than other muzzle grades. This is the first report indicating the segregation of MC1R genotypes and the inheritance of coat color through family lines in KNBC. The mating system proposed from this study may increase the possibility of brindle coat color appearance in KNBC.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.517-527
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• 2018

The current study investigated in vitro anti-diabetic and neuroprotective effects of the ethyl acetate fraction in Actinidia arguta sprouts (EFAS), on $H_2O_2$ and high glucose-induced cytotoxicity in human neuroblastoma MC-IXC cells. EFAS had high total phenolic and total flavonoid contents. An assessment of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity of EFAS, as well as its potential for inhibiting malondialdehyde production, indicated that EFAS may possess significant antioxidant properties. EFAS exerted inhibitory effects on ${\alpha}-glucosidase$ via glycemic regulation which forms advanced glycation end products. In addition, EFAS exhibited significant acetylcholinesterase inhibitory effects. Moreover, EFAS displayed protective effects against $H_2O_2$ and high glucose-induced cell death, and inhibited the generation of reactive oxygen species in MC-IXC cells. Finally, the main physiological compound of EFAS was identified via high performance liquid chromatography as a rutin.

• Tuberculosis and Respiratory Diseases
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• v.40 no.5
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• pp.483-494
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• 1993

Cell surface antigenic relationships between pathogenic mycobacteria have been investigated by the enzyme-linked immunosorbent assay using phenolkilled cells and their rabbits antisera. Homologous and heterologous reactions of Mycobacterium avium-intracellulare antisera before and after homologous and heterologous absorption revealed a close antigenic relationship between strains of the same species and between species if they were members of M. avium(MA)-intracellulare(MI)-scrofulaceum(MG) complex. MAI sera showed a considerable reaction with M. kansasii(MK) and tuberculosis(MTB), but not with the other species. MA(K40004) antiserum reacted with other mycobacteria except few strains of MI and 50~89% of homologous reaction was reduced by heterologous absorption with cells of MI or MS. Intraspecific reaction of MI antisera was natural1y stronger than interspecific reaction and different in extent due to a magnitude of antigenic sharing. Antigenic relationships between N-260D, N-260R, N-260T, and K41014 was somewhat closer than that with N-242D, N-257T, N-28ID, and N-275T. M. nonchromogenicum(MNC) antisera showed a strong interspecific reaction with exception of M. chelonei(MC) and triviale(MTV) to which they reacted weakly or none. Antigenic sharing with M. terrae(MTR) and MG(K30003) was next to intraspecific sharing. NC-3 shared antigens considerably with MA, MC, and M. fortuitum(MF) while NC-11 did not. MTR antisera showed a strong cross-reaction with MI but their homologous reaction was not reduced by MI absorption indicating a paucity of shared antigen of MTR surface. Intraspecific antigenic sharing of course was large with on exception between T-8 and T-13. A considerable amount of antigenic sharing was also found with MNC, MC and MF. Unlike T-8 serum, T-13 antiserum strongly cross-reacted with MA, MG, MK, and MTB. In general, antigenic relationships of mycobacteria, that have been elucidated in this study, well conformed to taxons delineated by the various biological and biochemical means.