• Environmental Analysis Health and Toxicology
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• v.6 no.1_2
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• pp.7-23
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• 1991

The present study was undertaken to examine the effect of butylhydroxyanisole (BHA) on the lead poisoning in Wister female rats. All experimental rats except normal group were fed with diets formulated by adding BHA in a range of 0.1% to 3.2% and aqueous solution of 1% lead acetate ad libitum through the experimental period. The results obtained are summarized as follows: 1) Lead sedimentation in kidney tissue was decreased with increasing experimental period and BHA level of lead plus BHA-treated groups in comparison with that of lead-treated control group. 2) The weights of lung, spleen and left/right (L/R) kidney were significantly decreased in comparison with those of lead-treated control group after 2 weeks of experimental period, but no difference was shown with those of normal group. 3) The weights of lung, spleen and L/R kidney were increased in lead-treated control group as compared with normal group after 2 weeks of experimental period, but no difference was shown with increasing experimental period. 4) Water intake was remarkably decreased in lead-treated control group as compared with normal group, but water intake by increasing BHA level of lead plus BHA-treated groups showed no significant difference from that of normal group. 5) These results suggest that BHA is effective for reducing the toxic effect of lead in rats.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2001.11a
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• pp.91-91
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• 2001

Nramp2, also known as DMT1 and DCT1, is a 12-transmembrane domain protein responsible for dietary iron uptake as well as metal ions such as lead, manganese, zinc, copper, nickel, cadmium, and cobalt. High expression of DMT1 increase lead uptake, and DMT1-dependent lead transport was H -dependent and inhibited by iron ions. The molecular mechanism of lead transport in CNS is as yet unknown. although interactions between iron and lead at the level of absorption have been known for some time. The process of lead uptake into astrocytes was not known yet. Nramp2 may mediate transport of heavy metal into astrocytes. We investigated whether Nramp2 mediate transport of lead into astrocytes. And we do whether Nramp2 was expressed highly by deprivation of iron in Astrocytes, and lead uptake into astrocytes was influenced by expression of Nramp2. Immortalized human fetal astrocyte(SV-FHA) cells were cultured in medium containing Dulbecco's modified Eagle's medium and treated with Deferoxamine. Northern blot analysis was done for determining mRNA level of DMT1 and lead uptake assay was done in incubation condition of pH 5.5 and 7.4.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.265-271
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• 2008

TCP(Tape Carrier Package), COG (Chip On Glass), COF(Chip On Film) are three methods for connecting LDI(LCD Driver IC) with LCD panels. Especially COF is growing its portion of market place because of low cost and fine pitch correspondence. But COF has a problem of the lead broken failure in LCD module process and the usage of customer. During PCB (Printed Circuit Board) bonding process, the mismatch of the coefficient of thermal expansion between PCB and D-IC makes stress-concentration in COF lead, and also D-IC bending process during module assembly process makes the level of stress in COF lead higher. As an affecting factors of lead-broken failure, the effects of SR(Solder Resister) coating on the COF lead, surface roughness and grain size of COF lead, PI(Polyimide) film thickness, lead width and the ACF(Anisotropic Conductive Film) overlap were studied, The optimization of these affecting manufacturing processes and materials were suggested and verified to prevent the lead-broken failure.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.182-185
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• 2003

Temperature distribution and cooling load in binary current lead are analized, occurring fault current at DC Reactor type superconductor fault current limiter. It is assumed that Normal operating current is 300 A and fault current is 3000 A. Unsteady-state temperature distribution and cooling load of brass current lead optimized for 300 A and 1000 A are calculated by numerical method with TDMA. In the result of calculation, temperature increase in the brass current lead optimized for 300 A is higher than that in the brass current lead optimized for 1000 A, but the temperature increase in the brass current lead optimized for 300 A is not serious. Moreover, increase of cooling load in the brass current lead optimized for 300 A is higher than that in the brass current lead optimized for 1000 A, but normal cooling load in the brass current lead optimized for 300 A is lower than that in the brass current lead optimized for 1000 A. Therefore, designing current lead in superconductor fault current limiter had better to optimize for normal operating current.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.68-74
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• 2002

The lead has to be removed for the recycling of copper alloy. The lead cannot be removed from the copper alloy by oxidation. It can be removed by the evaporation because of its high vapor pressure. However, rare information is found on removal of lead from copper alloy. The purpose of present work is to provide a fundamental knowledges on the removal of lead from the copper alloy by evaporation. Gas injection was made in molten copper alloy, and the evaporation rate of lead was measured. The influence of Ar gas flow rata(2~4 L/min), initial contents of lead(2~4wt%Pb), temperature(1200~140$0^{\circ}C$) was investigated based on the thermodynamic and the kinetics. The rate constant is increased with increasing flow rate of Ar and temperature. Though amount of lead removed is increased with higher initial lead concentration, the rate constant is not changed significantly. The activation energy is estimated from the temperature dependence of the rate constant. Also removal of lead from the copper by adding chloride was made for the comparison.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.1954-1961
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• 2022

Lead-based fast reactor (LFR) has become one of the most promising reactors for Generation IV nuclear systems. A developing trend of LFR is high efficiency, along with operation temperatures up to 800 ℃ or even higher. One of key issues in the high-efficiency LFR is corrosion of cladding materials with lead at high temperatures. In this study, corrosion behavior of some refractory metals (Nb, Nb521, and Mo-0.5La) was investigated in static lead at 1000 ℃ for 1000 h. The results showed that Nb and Nb521 exhibited an intense dissolution corrosion with obvious lead penetration after corrosion, and lead penetration extended along the grain boundaries of the specimens. Furthermore, Nb521 showed a better corrosion resistance than that of Nb as a result of the elements of W and Mo included in Nb521. Mo-0.5La showed much better corrosion resistance than that of Nb and Nb521, and no lead penetration could be observed. However, an etched morphology appeared on the surface of Mo-0.5La, indicating the occurrence of corrosion to a certain degree. The results indicate that Mo-0.5La is compatible with lead up to 1000 ℃. While Nb and Nb alloys might be not compatible with lead for high-efficiency LFR at such high temperatures.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.77-86
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• 1995

Lead(II) removal efficiency by natural kaolinite was investigated through laboratory experiments. This study was conducted in two phases-sorption and desorption. In the adsorption study, the influence of sorption kinetics and sorption isotherm and various parameters such as pH, temperature, coexisting other heavy metal ions on the lead adsorption was investigated. And desorption study was carried out in order to find the re-usability of kaolinite as an adsorbent. The results of the study are as follows. 1. Sorption kinetics was investigated under the condition of 2.5 mg/l adsorbent concentration, pH 6.5$\pm$0.05, temperature $30\pm 0.5\circ$C, initial lead(II) concentration 25 mg/l. Adsorption rate was initially rapid and the extent of adsorption arrived at adsorption equilibrium with 73% adsorption efficiency in an hour. 2. The sorption isotherm experiment was made with different initial lead(II) concentration. A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the sorption intensity (1/n) was 0.47 and the measure of sorption (k) was 2.44. So, it was concluded that sorption of lead(II) by kaolinite is effective. 3. The effect of pH on lead(II) sorption by kaolinite shows that at a pH of 3, only 6% of the total lead(II) was adsorbed and at a pH 9, 97% of the lead(II) was removed. And the effect of temperature on lead(II) sorption by kaolinite shows that as the temperature increased, the amount of lead(II) sorption per unit weight of kaolinite increased. But the effect was minor (p<0.05). 4. Sorption isotherm of lead coexisting cadmium (II) or zinc (II) was lower than that of lead itself. It was caused by the result of competitive sorption to adsorption site. And there was no difference between the sorption isotherm of cadmium and zinc. 5. In desorption studies, only 5.12% desorption took place in distilled water, while 52.08% in 0.1 N hydrochloric acid. Consequently used kaolinite could be regenerated by hydrochoric acid.

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.958-970
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• 1996

This study was performed to investigate the effect of dietary calcium level on cadmium and lead toxicity in rats. Fifty-four male rats of Sprague-Dawely strain weighing 152$\pm$12g were blocked into 9 groups according to body weight, and were raised for 30 days. Nine experimental diets different with cadmium(0%, 0.04%), lead (0%, 0.071%) and calcijm(0.5%, 1.0%, 1.5%) levels were prepared. The results are summarized as follow. Weight gain, F.E.R.(food efficiency ratio), and weights of liver, kidney and femur were lower in cadmium exposed groups than those of heavy metal free groups. Weight gain F.E.R. and ash weight of lead groups were lower than those of heavy metal free groups. But, these were increased with increasing dietary calcium level. Cadmium and lead concentrations in blood, liver, kidney and femur were lower in rats fed 1.5% calcium than 0.5% calcium diet. Fecal cadmium and lead excretions were remarkably increased in 1.5% calcium groups, and cadmium and lead retention rates were decreased in 1.5% calcium groups. Metallothionein concentrations in liver, kidney and small intestine were higher in rats exposed to cadmium and lead. Calcium content in blood, femur and daily urinary and fecal calcium excretion were decreased by cadmium and lead additions, and increased in 1.5% calcium groups. Creatinine clearance were decreased with cadmium administratino and calcium addition. In conclusion, weight gain and organ weights were decreased with cadmium or lead administration. But, cadmium administration was more toxic than lead adminstration. Cadmium or lead toxicity was alleviated by increasing dietary calcium level. Especially, lead toxicity was alleviated in proportion to dietary calcium level.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1158-1163
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• 2006

More than 95% of lead, a environmental heavy metal, entering into blood accumulates in erythrocytes suggesting erythrocytes as an important target of lead toxicity. Recent studies reported that erythrocytes could contribute to blood coagulation via phosphatidylserine (PS) exposure in erythrocytes. However, in vivo effects of chronic lead exposure especially by drink-ing water on procoagulant activity of erythrocytes have not been studied yet. In the present study, we investigated the effects of chronic exposure of lead by drinking water on erythrocytes in rats. Groups of 40 male rats were provided with drinking water containing various concentrations of lead for 4 weeks and complete blood cell count, procoagulant activities of erythrocytes and platelets were evaluated with basic inspections on body weight and food/water consumption. The administration of lead containing drinking water increased the blood lead level (BLL) in a dose-dependent manner up to $22.39{\pm}2.26\;{\mu}g/dL$. Water consumption was significantly decreased while food consumption or body weight gain was not affected. In contrast to the previous findings with acute lead exposure, chronic lead exposure failed to increase PS exposure in erythrocytes with statistical significance although some trends of enhancement were observed. It implies that a certain adaptation might have happened in body during repeated exposure to lead, resulting in attenuation of PS exposure. With this study, we believe that a valuable information was provided for the study on the toxicological significance and the risk assessment of lead contaminated drinking water.

• Safety and Health at Work
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• v.3 no.3
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• pp.216-223
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• 2012

Objectives: The objectives of this study were to determine the lead levels in blood samples from nielloware workers, to determine airborne lead levels, to describe the workers' hygiene behaviors, and to ascertain and describe any correlations between lead levels in blood samples and lead levels in airborne samples. Methods: Blood samples and airborne samples from 45 nielloware workers were collected from nielloware workplaces in Nakhon Sri Thammarat Province, Thailand. Lead levels were determined by flame atomic absorption spectrometry (FAAS), at a wavelength of 283.3 nm. FAAS was used especially adequate for metals at relatively high concentration levels. Results: The geometric mean of the 45 airborne lead levels was 81.14 ${\mu}g/m^3$ (range 9.0-677.2 ${\mu}g/m^3$). The geometric mean blood lead level of the 45 workers was 16.25 ${\mu}g/dL$ (range 4.59-39.33 ${\mu}g/dL$). No worker had a blood lead level > 60 ${\mu}g/dL$. A statistically significantly positive correlation was found between airborne lead level and blood lead levels (r = 0.747, p < 0.01). It was observed that personal hygiene was poor; workers smoked and did not wash their hands before drinking or eating. It was concluded that these behaviors had a significant correlation with blood lead levels (p < 0.001). Conclusion: Improvements in working conditions and occupational health education are required due to the correlation found between blood leads and airborne lead levels.