• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1254-1262
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• 1998

This study has done to investigate the relationship between the icreased lipid oncentration caused by smoking and plama levels of vitamin A and vitamin E, antiodative enzyme activity, and lipid peroxidation , in 52 male smokers and 32 non-smokers, Dietary vitamin A and vitamin E intake was imilar in both smokers and non-smokers. Absolute plasma concentrations of vitamin A and vitamin E were not significantly different between two groups, whereas vitamin E/cholesterol ration in plasma was low or in smokers than in that of non-smokers(p<0.05). It was considered that this lowered effect was due to the elevated plasma lipid concentration rather than oxidant stress derived from smoking, in view of the fact that smokers had higher cholesterol (15.2%) adn LDL-C(26.6%) levels than non-smokers. In non-smokers, plasma thiobarbiturin acid reactive substances(TBARS) conrrelated positively with total cholesterol(r=0.63466, p<0.001), LDL-C level(r=0.57166, p<0.01) , and LDL-C/HDL-C ratio(r=0.45926, p<0.05) . Activities of glutathione perosidase(GSH-Px) , superoside dismutase(SOD), and catalse made no difference in both groups. However, it was observed in non-smokers that GSH-Px activity had negative correlations with total cholesterol(r=-0.67293, p<0.001), LDL-C level(r=-0.62878, p<0.001), and LDL-C/HDL-C ratio (r=-0.58824, p<0.01), indicating that there was a dependent relationship between lipid perosidation and plasma lipid level. The smokers also showed negative correlations for GSH-Px activity with total cholesterol (r=-0.29946, p<0.05) and LDL-c level (r=0.45914, p<0.001), and LDL-C/HDL-c ratio(r=-0.35438, p<0.05). It seemed that the lipid that the lipid level elevated by sustaines smoking resulted in reducing vitamin E/cholesterol ratio and proportion of antioxidant to oxidant load, and then GSH-Px activity, with insufficient removal of free radicals(TBARS 2.43$\pm$0.51 and 1.81$\pm$0.15nmol/ml in smokers and non-smokers, respectively). These findings suggest that higher plasma lipid levels may play a more important role in perturbing the antioxidant defense system including vitamin E status and GSH-Px activity, at least in circumstances that increase lipid concentration . In addition, in exposure to free radicals like those in cigarette smoke. In those cases the ratio of vitamin E/lipid in plasma can be a more indicator of vitamin E status than plasma levels of vitamin E alone.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.5
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• pp.518-524
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• 2004

The feasibility of Y(z) curve method of scanning acoustic microscope using high frequency transducer was experimentally studied for assessment of the thermal degradation in Co-based superalloy. Thermal degradation was performed to simulate the microstructural changes in Co-based superalloy arising from long term exposure at high temperature. Longitudinal wave velocity measured by pulse echo method using 10MHz transducer and leaky surface acoustic wave (LSAW) velocity measured by V(z) curve method using 200MHE transducer were measured to investigate the effect on thermal degradation. Ultrasonic velocity decreased as the aging time increased in both ultrasonic waves. Moreover, the low frequency longitudinal wave velocity decreased a little. Otherwise, the high frequency LSAW velocity drastically decreased up to a maximum of 4.7% at the aging time of 4,000hours. A good correlation was found between LSAW and Vickers hardness. Consequently, V(z) curve method of SAM using high frequency transducer could be a potential tool for assessing thermal degradation.

• Biomolecules & Therapeutics
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• v.9 no.1
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• pp.33-39
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• 2001

Antidotal efficacy of combinational prophylactics composed of physostigmine plus procyclidine, alone or in combination with antidotes such as atropine plus 2-pralidoxime or atropine plus HI-6, was evaluated in rats. Physostigmine (0.1 mg/kg) plus procyclidine (3 mg/kg), pretreated subcutaneously 30 min prior to subcutaneous exposure to organophosphates of militarily importance, exerted protection ratios of 7.2, 6.5, 4.0, 2.9 and 8.0 fold for tabun, saris, soman, cyclosarin and V-agent, respectively. In comparison, low effects (1.7 fold for soman and 1.3 fold for cyclosarin) were achieved with the traditional antidotes atropine (17.4 mg/kg) plus 2-pralidoxime (30 mg/kg) administered intramuscularly immediately after organophosphate, in contrast to high effects (5.5 fold for soman and 160.0 fold for cyclosarin) with atropine (17.4 mg/kg) plus HI-6 (125 mg/kg), although the protection ratio markedly decreased when treatment of antidotes was delayed. Note- worthy, the combinational prophylactics markedly potentiated the effects of antidotes to higher than 5.0 fold in all cases. In addition, the combinational prophylactics fully prevented the seizures and excitotoxic brain injuries induced by a high dose (100 mg/kg, 1.3 LD$_{50}$) of soman. Taken together, it is suggested that the prophylactics composed of physostigmine and procyclidine, in combination with posttreatment antidotes, could be a promising regimen for the prevention of lethality, seizures and brain injuries induced by organophosphates possessing diverse properties.s.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.2
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• pp.99-104
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• 2017

Refractories used in low-rank coal gasification reactors are usually exposed in a highly corrosive $H_2S$ gas at less than $1000^{\circ}C$, and their mechanical properties such as erosion resistance and fracture strength decline with the exposure time. However, the cause of the degradation of the mechanical properties has little reported yet. In this paper, two kinds of castable refractories with different refractoriness had been exposed in a $H_2O/N_2/H_2S$ mixed gas with high $H_2S$ content for 100 hours at $900^{\circ}C$, and the changes of microstructure, crystalline phases and erosion resistance were compared before and after the corrosion test. The weight of the refractories decreases due to the elution of silica in the specimens after the corrosion test. The capillary porosities of the samples are reduced, but the erosion resistance of the samples is fatally weakened after the corrosion test. There also are changes in constituent phases; dmitryivanovite ($CaAl_2O_4$) and amorphous silica ($SiO_2$) disappear, and gypsum ($CaSO_4{\cdot}2H_2OS$) and kaolinite ($Al_2Si_2O_5(OH)_4$) newly appear after the corrosion test. It is obvious that the phase change from dmitryivanovite that works as a binding agent in the castable refractory to gypsum is the main reason of the degradation of the erosion resistance, because the mechanical properties of gypsum are much poorer than those of dmitryivanovite.

• Journal of Environmental Health Sciences
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• v.46 no.1
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• pp.1-10
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• 2020

Objectives: This study intends to evaluate the ecological risk of lead (Pb), arsenic (As), and their compounds according to the 2010 action plan on inventory and management for national priority chemicals and provide calculations of risks to the environment. By doing so, we aim to inform risk management measures for the target chemicals. Methods: We conducted species sensitivity distribution (SSD) analysis using the collected ecotoxicity data and obtained predicted no effect concentrations (PNECs) for the in-water environment using a hazardous concentration of 5% (HC5) protective of most species (95%) in the environment. Based on the calculated PNECs for aquatic organisms, PNEC values for soil and sediment were calculated using the partition coefficient. We also calculated predicted exposure concentration (PEC) from nation-wide environmental monitoring data and then the hazard quotient (HQ) was calculated using PNEC for environmental media. Results: Ecological toxicity data was categorized into five groups and five species for Pb and four groups and four species for As. Based on the HC5 values from SSD analysis, the PNEC value for aquatic organisms was calculated as 0.40 ㎍/L for Pb and 0.13 ㎍/L for As. PNEC values for soil and sediment calculated using a partition coefficient were 77.36 and 350.50 mg/kg for Pb and 24.20 and 112.75 mg/kg for As. The analysis of national environmental monitoring data showed that PEC values in water were 0.284 ㎍/L for Pb and 0.024 ㎍/L for As, while those in soil and sediment were respectively 45.9 and 44 mg/kg for Pb, and 11.40 and 19.80 mg/kg for As. Conclusions: HQs of Pb and As were 0.70 and 0.18 in water, while those in soil and sediment were 0.59 and 0.13 for Pb and 0.47 and 0.18 for As. With HQs <1 of lead and arsenic in the environment, their ecological risk levels are found to be low.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.323-333
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• 2009

Parabens are alkyl esters of p-hydroxybenzoic acid, which are widely used in foods, cosmetics, and pharmaceutic products as preservatives. Absorbed parabens are metabolized fastly and excreted. Actually human body is exposed to complex mixture of parabens. Safety assessment at various toxicological end points revealed parabens have a little acute, subacute and chronic toxicities. Some reports have argued that as parabens have estrogenic activity, they are associated with the incidence of breast cancer through dermal absorption by cosmetics. There is an inference that antiandrogenic activity of parabens may give rise to a lesion of male reproductive system, but also there is an contrary. At cellular level, parabens may inhibit mitochondrial function of sperms and androgen production in testis, but also there is an contrary. Parabens seem to have little or no toxicity in embryonic development. Parabens can cause hemolysis, membrane permeability change in mitochondria and apoptosis, suggesting cellular toxicity of parabens. Parabens evoked endocrine disruption in several fish species and have toxic effect on small invertebrates and microbes. Therefore, the toxicity of parabens should be considered as a potentially toxic chemical in the freshwater environment. In conclusion, though parabens may be considered as a low toxic chemical, more definite data are required concerning the endocrine disrupting effect of parabens on human body and aquatic animals according to route and term of exposure as well as the residual concentration of parabens.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.12 s.148
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• pp.1527-1534
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• 2005

In order to clarify the characteristics of the thermo-physiological responses of the child and to understand the influence of the country where the child has grown up on the responses, the thermo-physiological responses of the Japanese children(J group) and the Korean children(K group) were examined. The subject wearing shorts was exposed first to a thermo neutral room$(Ta=28.5^{\circ}C)$ for 1 hour, then transferred to a cold$(Ta=22^{\circ}C)$ or a hot$(Ta=37^{\circ}C)$ room for 1 hour. The experiment was done in the climate chamber of Bunka Women's University in the summer of 1997 for Japan, and in the climate chamber in the Keimyung University in the summer of 1998 for Korea. The subjects consisted of 5 boys and 5 girls aged 7-9 years in Japan and 4 boys and 4 girls aged 7-9 years in Korea. As a result: 1) The rectal temperature increased slightly with a rise in air temperature. K group showed a slightly higher rectal temperature. 2) The skin temperature of the hand and foot decreased conspicuously during cold exposure. It was more in the K group than in the J group. 3) Relative local sweat rates were similar in the two groups at $22^{\circ}C\;and\;28.5^{\circ}C$, while they were considerably different at $37^{\circ}C$. Even perspiration was observed over the whole body in the J group but the perspiration was large in the trunk and low in the extremity in the K group. 4) The heart rate was higher in the J group than in the K group but it increased with the rise of the air temperature in both groups.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.240-248
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• 1997

References on the cooking and processing losses of organophosphorus (OP) pesticides in foods were collected and analyzed to indicate that the average removal of whole pesticides being 45% in water washing, 56% in detergent washing, 91% in peeling of fruits, 5l% in blanching-boiling of vegetables, 90% in milling and processing of grains. The theoretical maximum daily intake (TMDI) calculated from the food intake and Korea maximum residue limits showed that 4 among 11 pesticides exceeded the acceptable daily intake (ADI). The estimated daily intake (EDI) calculated from the food intake and monitoring data reached 17.2% of ADI on the assumption that the toxicity of OP pesticides appears as an additive effect. The % ratio of ADI for individual pesticides was 6.1% in diazinon, 5.8% in fenthion, 3.3% in fenitrothion and very low in other pesticides. By applying reduction factors to the EDI, the removal ratio of OP pesticides in cooking and processing appears to be over 50%. In summary, the exposure level of Korean population toward whole OP pesticides was estimated to reach 23% of ADI, which would not cause any health rick as yet, but calls for a systematic risk assessment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.6
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• pp.725-728
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• 1996

This study was conducted to investigate effect of leaf temperature on light response and respiration during short-term exposure to a sequnce of PPFD cycle(100-200-300-400$\mu$ mol m$^{-2}$ s$^{-1}$ ) under increasing leaf temperature sequnce up to 3$0^{\circ}C$ and in dark condition, increasing up to 46$^{\circ}C$ with step size (1$^{\circ}C$) in Panax ginseng C. A. Meyer. When leaflet exposed to low light intensity and temperature, Rubisco activity was higher than remained activity in high condition. Leaves adapted to 100$\mu$mol m$^{-2}$ s$^{-1}$ PPFD had a peak response similar to that of 200$\mu$mol m$^{-2}$ s$^{-1}$ at 18$^{\circ}C$, but in above PPFD cycle(300, 400$\mu$mol m$^{-2}$ s$^{-1}$ ) it represented at 17$^{\circ}C$ and 16$^{\circ}C$, re-spectively. $CO_2$ evolution in dark condition increased rapidly when leaf temperature was increased up to 28$^{\circ}C$ and then 'dipped' below steady-state level from above 4$0^{\circ}C$. Thus, Pananx ginseng is able to take advantage of irradiance increase and decrease of $CO_2$ evolution in dark condition to control leaf temperature.mperature.

• 한국해양학회지
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• v.26 no.1
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• pp.24-37
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• 1991

Marine benthic diatoms and environmental factors were studied at 60 sites on the Mangyung-Dongjin tidal flat of the west coast of Korea. Sediment samples were taken quantitatively from the upper 5 mm layer to obtain a representative estimate of the epipelic and epipsammic cell concentration. Surface sediments taken simultaneously with the quantitative diatom samples were analysed for the grain size. Exposure duration of study sites were calculated by the tide data recorded at Kunsan Outer-Harbour. Coarse sediments dominated mainly on the offshore coastal and lower tidal flat, whereas fine sediments occurred on inner and higher tidal flat. Total 371 diatom taxa were collected and the genera represented by a great number were Navicula and Nizschia. The 16 abundant species occupying more than 1% of total cell number are of the following: Paralia sulcata, Navicula sp. 1, Navicula arenaria, Cymatosira belgica, Amplora holsatica, Amphora coffeaeformis, Achnanthes hauckiana, Rhaphoneis amphiceros, Thalassionema nitzschioides. Navicula sp. 2, Dimeregramma minor, Amphora sp. 1, Cyclotella atomus, C, striata, Nitzschia kuetzingiana, Stephanodiscus sp. 1. The distribution pattern of these dominant species are described in relation to the habitat condition. Most of these species showed high densities in fine sediments. However, they occurred even silty sand and sandy sediments in low abundance. The epipsammic forms belonging to the Araphidineae and Monoraphidineae were restricted on the lower tidal flat. The typical species found in coarse sediments were: Cocconeis sp. 1, Opephora martyi, Amphora sabyii, Dimeregramma minor var. nana, Fragilaria virescens var. oblongella, F. virescens, Cocconeis grata. The higher tidal flat consisting of fine sediments showed relatively higher cell numbers than the lower tidal flat. River mouth region was the highest in abundance.