• 대한한의학방제학회지
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• 제17권2호
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• pp.143-150
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• 2009

The effects of aqueous extract of Schizandrae Fructus (AESC) on lead (Pb)-induced changes of monoamine neurotransmitters in the hippocampus (HIP) of adult rats were investigated. Male Sprague-Dawley rats were received intraperitoneal (i.p.) administration of Pb acetate (5 mg/kg/d) for 28 days and sacrificed 7 days after the last administration. Concentrations of norepinephrine (NE), dopamine (DA), serotonin (5-HT), 5-hydroxyindole acetic acid (5-HIAA) in HIP were measured by HPLC. There were significant decreases of NE, DA, 5-HT and 5-HIAA in Pb treated rats (P < 0.05), while pretreatment with AESC (100 mg/kg/d or 300 mg/kg/d, p.o., 2 h before Pb) greatly inhibited the decrease of monoamine transmitters, respectively (P < 0.05). Also, AESC (300 mg/kg/d) significantly increased the reduction of glutathione contents and superoxide dismutase activities in HIP induced by chronic Pb. These results suggest that AESC ameliorates Pb-induced depletion of monoamine neurotransmitters in HIP through its antioxidant activity.

• Environmental Engineering Research
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• 제10권3호
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• pp.112-121
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• 2005

The effectiveness of quicklime-based stabilization/solidification (S/S) in immobilizing lead (Pb) was assessed by performing semi-dynamic leaching tests (ANS16.1). In order to simulate landfill leaching conditions, the ANS 16.1 test was modified by using 0.014 N acetic acid (pH = 3.25) instead of distilled water. Artificial soil samples as well as field soil samples contaminated with Pb were tested. The effectiveness of quicklime treatment was evaluated by determining diffusion coefficients ($D_e$) and leachability indices (LX). A model developed by de Groot and van der Sloat was used to elucidate the controlling Pb leaching mechanisms. Overall, upon quicklime treatment Pb leachability was significantly reduced in a]l of the samples tested. The mean LX values were higher than 9 for an artificial soil sample containing 30% kaolinite treated with 10% quicklime and for a field soil sample treated with 10% quicklime, which suggests that S/S treated soils can be considered acceptable for "controlled utilization". Moreover, quicklime treatment was more effective in artificially contaminated soil with high kaolinite content (30%), indicating the amount of clay plays an important role in the success of the treatment. The controlling Pb leaching mechanism was found to be diffusion, in all quicklime treated samples.

• 보존과학회지
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• 제34권2호
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• pp.69-76
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• 2018

납 계열 안료(연백, 밀타승, 연단)는 대기환경에서 변색이 쉽게 일어나는 것으로 알려져 있다. 본 연구는 산소($O_2$)와 이산화탄소($CO_2$)가 납 계열 안료인 연백, 밀타승 및 연단의 변색에 어떤 영향을 미치는지 관찰하였다. 실험 결과, $O_2$(99%, RH 99%)와 $CO_2$(36,000 ppm, RH 99%) 환경 하의 대부분의 안료 시편에서 ${\Delta}E=5.0$ 이상의 변색이 관찰되었다. 주사전자현미경 관찰에서는 안료입자의 모서리가 마모되는 현상을 관찰하였다. 또한 XRD 분석에서 열화 후 각 안료의 특징적 회절피크가 약해졌으며, $CO_2$(36,000 ppm, RH 99%)에 노출시킨 연백, 밀타승, 연단 시편은 탄산납의 주요 회절피크가 확인되었다. 특히 밀타승 시편은 Plattnerite($PbO_2$) 결정이 확인되었으며, 연백 시편은 기존의 XRD 피크들이 사라지고 Cerussite($PbCO_3$)가 동정되는 특징도 확인되었다. 이를 통해 고습의 $CO_2$ 환경에 납 계열 안료가 노출될 경우, 변색을 동반한 화학적 변화가 일어나는 것을 확인할 수 있었다.

• 자원환경지질
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• 제38권2호
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• pp.129-134
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• 2005

수중생물과 그 생물이 살았던 물과의 Sr 동위원소 조성은 크게 다르지 않으나, Pb 동위원소비는 Sr 동위원소와는 달리 생물과 그 생물이 살았던 물과 상이한 값을 보인다. 이 두 동위원소를 환경추적인자로 동시에 적용할 목적으로 담수에 사는 수중생물인 다슬기(Semisulcospira libertina) 껍질의 두 동위원소비를 측정하여 보았다. 하천수에 사는 다슬기 껍질의 Sr 동위원소비는 그들이 살았던 하천수의 동위원소비와는 같은 값을 보이지만, 채취지역에 따라서는 다른 값을 가진다. 하천수의 Sr 동위원소조성이 다른 것은 각 하천수의 기반암의 Sr 동위원소가 서로 다르기 때문으로 결국 하천수중의 Sr은 기반암으로부터 유래하고 다슬기 껍질의 Sr은 하천수에서 기인한 것으로 볼 수 있다. 반면에 Pb 동위원소비는 하천수와 다슬기 껍질이 서로 다른 값을 보이는 것은 하천수에 용해된 Pb이 다슬기가 흡수 가능한 Pb과는 다른 것으로 생각되며, 다슬기 껍질의 Pb 동위원소비는 강우의 Pb 동위원소비와 유사하다. 하천수에 용해된 Pb은 기반암에서 유래한 것이 아니라 토양 중에 집적된 대기기원의 Pb이 대부분인 것으로 생각된다.

• Biomolecules & Therapeutics
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• 제12권4호
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• pp.209-214
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• 2004

Lead has long been considered as a toxic environmental pollutant that severely damages the central nervous system. In various neurogenerative diseases, actrocytes become activated by proinflammatory cytokines. In the present study, we investigated whether lead (Pb$^{2+}$) affects inducible nitric oxide synthase (iNOS) expression in activated glial cells. Rat primary glial cells were stimulated with lipopolysaccharide (LPS, 1 ${\mu}$g/ml) plus IFN$_{\gamma}$(100 U/ml). Pre-treatment of Pb$^{2+}$ increased nitric oxide (NO) production in LPS/IFN$_{\gamma}$-stimulated glial cells. Lead itself, however, suppressed the basal production of NO in control glial cells. Addition of the iNOS inhibitors L-NAME (1 mM) and L-NNA (800 ${\mu}$M) prevented the Pb$^{2+}$-induced increase in NO production. Western blot analysis showed that pre-treatment of Pb$^{2+}$ augmented LPS/IFN$_{\gamma}$-induced increase in iNOS immunoreactivity, which was well correlated with the increased NO production. In addition, pre-treatment of Pb$^{2+}$ synergistically increased the iNOS mRNA expression induced by LPS and IFN${\gamma}$. The present results indicate that lead intoxication adversely affect brain function by potentiating iNOS expression and NO production in activated glial cells observed in various neurodegenerative diseases.

• 한국표면공학회지
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• 제51권5호
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• pp.257-262
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• 2018

Cesium lead halide perovskite quantum dots (QDs) have recently emerged as highly promising opto-electronic materials. Despite the relative facile anion exchange reactions in cesium lead halide perovskite QDs, in depth study of the anion exchange reactions such as reaction kinetics are required that can provide insight into the crystal transformation in the cesium lead halide perovskite QDs. Herein, we investigated the anion exchange reaction from $CsPbI_3$ QDs to $CsPbBr_3$ QDs with varying the particle size of the starting $CsPbI_3$ QDs. By characterizing the PL spectra in the anion exchange reaction process, we observed that discontinuous PL peak shifts during I-to-Br anion exchange reaction in starting $CsPbI_3$ QDs over a critical size. Origin of the discontinuous I-to-Br anion exchange kinetics are mainly due to thermodynamically unstable nature of the $CsPb(Br/I)_3$ alloy QDs.

• Journal of Nutrition and Health
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• 제38권5호
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• pp.380-385
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• 2005

This study was designed to investigate the effects of mulberry leaf powder supplementation on lead (Pb) status and mineral (Ca, Fe, Cu and Zn) content in Pb-administered rats for 4 weeks. Thirty two male rats were divided into 4 groups: a control, Pb, Pb5M (500 ppm $Pb + 5\%$ mulberry leaf powder), and Pb10M (500 ppm $Pb + 10\%$ mulberry leaf powder). There were no significant differences in food intake and initial body weight among groups. Mulberry leaf powder treatments showed significant decreases in food efficiency ratio and body weight gain. But FER of $Pb5M\%$ and Pb10M were significantly increases than that of Pb group. The levels of serum aspartate transaminase (AST) and creatinine were decreased by mulberry leaf powder treatment. Minerals content of liver and kidney were significantly decreased in the Pb groups than that of control group. Whereas, fecal minerals content were significantly increased in the Pb5M and Pb10M than those of control group. Pb content of serum, liver and kidney was significantly increased in the Pb group than those of control group. However, by mulberry leaf powder administration (Pb5M and Pb10M), Pb level of serum, liver and kidney were lowered than that of Pb group. And fecal Pb excretion was significantly increased in the Pb5M and Pb10M than that of Pb group. These results showed mulberry leaves were effective for lowing Pb accumulation in serum, organs, which may have potential to prevent Pb toxicity.

• 한국융합학회논문지
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• 제13권3호
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• pp.113-124
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• 2022

본 연구는 한국 성인 여성의 체내 납 (Pb) 노출 수준과 심혈관질환 (CVD) 사이의 관계를 분석하기 위해 수행되었다. 2017년 국민건강영양조사 (KNHANES)에 참여한 만 19세 이상 성인 1,821명을 대상으로 혈중 납과 허혈성 심장 질환 (IHD), 뇌졸중 및 고혈압의 자가 보고한 의사 진단에 대한 단면 자료를 이용하였다. CVD 및 혈중 납 농도는 로지스틱 회귀분석을 통해 분석하였고, pearson 상관계수를 이용하여 요인 간의 상관관계를 확인하였다. 혈중 납 수치 증가는 여성에서만 허혈성 심장 질환 (OR 5.68, 95% CI 1.01-17.51) 및 고혈압 (OR 3.37, 95% CI 2.24-5.07) 위험 증가와 연관이 있었다. 또한, 혈중 납과 영양소 섭취 사이에는 상관관계가 있었다. 이는 혈중 납 수치가 CVD 발병의 주요 예측 인자로 사용될 수 있으며 여성이 납 노출과 관련된 IHD 및 고혈압에 더 취약하다는 것을 시사한다.

• 한국응용과학기술학회지
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• 제25권1호
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• pp.41-47
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• 2008

This study was conducted to made a grid alloy (Pb-Ca-Sn-Al) which has a temporary composition ratio in order to improve the efficiency of lead acid batteries. The positive activity material made a 3BS(tri-basic lead sulfate; $3PbO{\cdot}PbSO_4{\cdot}H_2O$) by a low temperature curing and it evaluates the plate efficiency through the life cycle testing. The initial current capacity of low temperature curing plate was excellent but the life cycle was not good (S1). As for the S2 plate, however, the initial current capacity and the life cycle were superior.

• 한국세라믹학회지
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• 제25권4호
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• pp.321-328
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• 1988

The sintering phenomena, electrical resistivity, dielectric and piezoelectric properties of lead titanate ceramics modified by the partial substitution of La for Pb and Mn for Ti, (Pb1-1.5xLax)(Ti1-yMny)O3 ceramics, have been investigated. In (Pb1-1.5xLax)(Ti1-yMny)O3 system, with increasing lanthanum content, the realtive bulk density increased, but the Curie point and tetragonality (c/a) decreased. The tetragonal-to-cubic phase transition boundary existed in the range of 0.20