• Development and Reproduction
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• v.10 no.2
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• pp.115-125
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• 2006

The present experiment was performed to confirm the effects of selenium on maturation and viability of mouse oocyte. Maturation of oocytes was observed by microscope, Germinal vesicle breakdown(GVBD) and polar body formation(PB) were confirmed at 2.5, 13 hours after in vitro culture. Viability of oocytes was observed by microscope. Normal and abnormal oocytes were distinguished by morphological change in vitro culture for 72 hours. Glutathione(GSH) content of collected oocytes from individual stage also was measured by glutathione assay using spectrophotometer. The results obtained were as follows; The low concentration of selenium($0.005\;{\mu}g/mL{\sim}0.5\;{\mu}g/mL$) increased the maturation rate of germinal vesicle(GV) oocytes to GVBD and PB oocytes. The high concentration of selenium($5\;{\mu}g/mL$) decreased the maturation rate. The low concentration of selenium increased the viability rate of PB oocytes. The high concentration of selenium did not affect the viability rate. The low concentration of selenium increased the GSH content in PB oocytes. The high concentration of selenium decreased GSH content. GSH content in PB oocyte was much higher than that in GVBD oocyte. The results indicate that the low concentration of selenium increases the maturation rate by helping quality elevation of oocyte and minimizing damages of oxidative stress generated from metabolism process. The low concentration of selenium also increases the viability rate by increasing GSH content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.2
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• pp.109-115
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• 1993

This study was designed to investigate the effects of dietary protein and calcium levels on Ca, Fe, Cu, Zn and Mg accumulation of the tissue of the Pb-administered rats. Male Sprague-Dawley rats were assigned to a 3$\times$3$\times$2 factorial design with 3 levels of protein (40%, 15%, 6%), 3 levels of Ca (1.2%, 0.6%, 0.12%) and 2 feeding periods (3 and 7 weeks). The control group was included separately. The rats were exposed to the drinking water containing 2,000ppm of lead. Calcium contents in serum, liver and femur were decreased with Pb administration. Calcium contents in serum and femur were reduced with dietary protein and Ca levels. Level of serum Fe showed no significant difference with Pb administration in the rats fed the high Ca diet. Iron content in liver was not affected by the lead when the rats fed the diet containing high protein and Ca. Level of serum Cu was lower in the Pb added groups than in the control group and tended to be reduced with decreasing dietary protein and Ca levels. Copper content in liver was not affected by the lead when the rats fed the high Ca diet. Level of serum Zn was decreased in the low protein-low Ca group. Magnesium content in serum was decreased with Pb administration when the rats fed the diet containing low protein and Ca. However, magnesium content in liver was reduced with Pb administration and affected only by dietary protein level.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.139-146
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• 1999

The seasonal changes of the flora at three samples sites such as Sockchong, Wang-gung and Chukrim hot spring by drained thermal waters were investigated from 1997 to 1998. Monthly occurrence of plant species in February and October showed more abundantly control site than that of heavy and/or light polluted sites. This trend demonstrated similarly in terms of seasonal changes of leaf area and plant growths, both fresh and dry weight, too. Cu, Zn, Ni and Pb content including plants from Sockchong hot spring site were increased from April to September at test area than that of control, while that was decreased in October. But Zn and Pb content holding plants from Wang-gung hot spring site represented higher test site than that of control. In short impacts on aquatic plants communities by thermal wastewater of sampled area have happened in the season of low temperature, and their restorations have done in summer season.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.2
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• pp.147-151
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• 1986

A study was carried out to investigate yield, yield components, and change of chemical components in rice plants grown under different concentration of lead compound in nutrient solution of sandy culture. The results obtained are as follows. 1. Increasing lead concentration in culture solutions, pb content in the plant was increased and crop yields were decreased. 2. The critical pb concentration at which yield was declined, was 13.6 ppm. 3. As adding higher concentration of lead in nutrient solutions, concentration of lead in rice plant was significantly increased on leaf blade, and brown rice in pb. 4. Yield loss was closely related to pb content in leaf blade.

• Preventive Nutrition and Food Science
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• v.18 no.4
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• pp.249-255
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• 2013

Yam (Dioscorea) has long been used as foods and folk medicine with the approved positive effects for health promotion. Although consumption of yam products is increasing for health promotion, reports for the metal contamination in commercial yam powder products to protect the consumers are lacking. In this study, we aimed to assess whether the commercial yam powder products were heavy metal contaminated or not using the yam products from six commercial products from various places in South Korea. The contents of heavy metals (Cd, Cr, As, Pb, Ni, and Sn) in yam powder products were measured and compared to national and international food standard levels. Also, the metal contamination was monitored during the food manufacturing steps. The study results showed that the contents of heavy metals (Cd, Cr, As, and Pb) in yam powder products are similar to those in national 'roots and tubers' as well as in various crops. In comparison to three international standard levels (EU, Codex and Korea), Cd content in yam powder products was lower but Pb content was 5 times higher. Also, Pb, Ni, and Sn may have the potential to be contaminated during food manufacturing steps. In conclusion, the level of heavy metals (Cd, Cr, As, Ni, and Sn) except Pb is considered relatively safe on comparison to national and international food standard levels.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.855-858
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• 2003

When the PbO-based flux system is used in the Liquid Phase Epitaxy (LPE) method for Yttrium Iron Garnet (YIG) thick film, the effect of Pb ions incorporated into the grown crystal; increase the lattice parameter, changed the uniaxial magnetic anisotropy constant (Ku) or conductance of grown film. It exerts a bad influence on physical property such as increasing optical absorption of grown film. The content of the Pb ion in crystal was decreased by volatilization of Pb ion after annealing; therefore, the lattice parameter of film was reduced on an average 0.0115 ${\AA}$ by the the Pb ion.

• Journal of Welding and Joining
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• v.16 no.3
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• pp.148-156
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• 1998

The purpose of this study is to investigate the characteristics of Pb-Free Sn-2%Ag-Bi solder alloys. The solder alloys used in this study is Sn-2%Ag-(3,5,7,9%) Bi It is examined that their properties such as melting range, wettability, microstructure, microhardness, and tensile property. The addition of Bi(3,5,7,9%) lowered the melting point of the solder and the melting range was 196~203$^{\circ}C$. The wettability of the solder as equal to that of Sn-37% Pb solder. The morphology of structure did not change largely by addition of Bi. But the structure of cellular dendrite of linear type displayed. The tensile strength of the solder was superior to that of Sn-37%Pb solder. But the elongation was inferior to that of Sn-37%Pb solder. The hardness of Sn-2%Ag solder was tow times and that of Sn-2%Ag-Bi solder was three times of that in Sn-37%Pb solder. But the effect of increment of Bi content did not change largely.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.213-217
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• 2000

In order to select more proper plants for phytoextraction at the heavy metal polluted areas, 11 species of non-edible plants were cultivated at the cadmium(Cd) and Lead(Pb) treated soils and analyzed the content of the absorbed Cd and Pb in each part of plants. Plants include three fibers(Linum usitatissimum, Cannabis sativa, Gossypium spp.), three flowers(Calendula officinalis, Rhododendron lateritium, Portulaca grandiflora), and five trees(Pinus thunbergii, Magnolia kobus, $Populus\;nigra\;{\times}\;P.$ maximowiczii, Euonymus japonica, Fraxinus rhynchophylla). Yield of tree species were higher than that of fiber and flower species. Cd and Pb were highly accumulated in root rather than leaves and stems. The Cd content of plants was in the order Portulaca grandiflora > Calendula officinalis > Gossypium spp. > Linum usitatissimum, Pb was Cannabis sativa > Linum usitatissimum > Fraxinus rhynchophylla. Total absorbed Cd by each plant was in the order $Populus\;nigra\;{\times}\;P.$ maximowiczii > Euonymus japonica > Rhododendron lateritium, but Pb was $Populus\;nigra\;{\times}\;P.$ maximowiczii > Rhododendron lateritium > Euonymus japonica. Total absorbed Cd and Pb contents in plants were negatively correlated with the residual Cd and Pb in the treated soils. It was estimated that $Populus\;nigra\;{\times}\;P.$ maximowiczii, Euonymus japonica, Fraxinus rhynchophylla, and Rhododendron lateritium were the most effective species for phytoextraction in the polluted area considering yield and heavy metal uptake.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.914-919
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• 2000

This study was designed to investigate the effects of korean pueraria radix extract in Pb administered rats. Forty-two male Sprague-Dawley rats weighing $100{\pm}10g$ were used for this experiment and divided into following 6 groups; control group, 3% pueraria radix group(3% pue.), 100 ppm and 200 ppm alone pb group, 100 ppm and 200 ppm alone pb group with 3% pue. Tissue weight of liver, lung, stomach, heart, kidney and spleen of pb exposed rats were reduced by 3% extracts of pueraria radix group. The Pb content in the rats tissue of pb alone administered group was lower than in the rats tissue of pb group with 3% pue. GPT and GOT were increased in pb-administered group and lower in the 3% extracts of pueraria radix group. LDH was lower in the 3% extracts of pueraria radix-pb group than in the pb group. ChEase was higher in the 3% extracts of pueraria radix group than in the pb alone administered group.

• Korean Journal of Pharmacognosy
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• v.13 no.3
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• pp.102-105
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• 1982

Nine trace elements in Bear Galls(Fel Ursi) studied in this paper are Na, Mg, K, Ca, Cu, Zn, Fe, Pb and Ge. The contents of Na, Mg, K, Ca, Cu, Zn, Fe, Pb are determined by atomic absorption spectrometry and Ge is determined by graphite atomic absorption spectrometry. In both methods, the sample is digested with nitric-perchloric acid and then ashed. The results of analysis are shown in table and the result obtained from this study are as follows. a. The highest content of trace element of Bear Gall is Na and other elements are getting lower in order of K, Mg, Ca, Ge, Zn, Fe, Cu, and Pb. b. Particularly the content of Ge in Bear Gall was determined.