• Advances in environmental research
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• 제7권3호
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• pp.225-237
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• 2018

The sorption of metal ions with low-cost adsorbents plays an important role in sustainable development. In the present study, the efficacy of sugarcane bagasse, rain tree fruits (samaneasaman), banana stem and their mixtures, used as bio-sorbents, in the removal of Cu(II) and Pb(II) ions from aqueous solution is evaluated. Batch studies are conducted, and residual ions were measured using Inductively Coupled Plasma (ICP)-atomic spectrometer. Effect of pH, initial metal ion concentration, reaction time and adsorbent dosage are studied. The Pb(II) removal efficiency was observed to be 97.88%, 98.60% and 91.74% for rain tree fruits, banana stem and a mixture of adsorbents respectively. The highest Cu(II) ion removal was observed for sugarcane bagasse sorbent with an efficiency of 82.10% with a pH of 4.5 and a reaction time of 90 min. Finally, desorption studies were carried out to study the leaching potential of adsorbent, and it was found that the adsorbent is stable in water than the other leaching agents such as HCl, ammonium acetate, Sodium EDTA. Hence, these adsorbents can be effectively used for the removal of these heavy metals.

• 한국지반환경공학회 논문집
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• 제2권3호
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• pp.17-35
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• 2001

본 연구에서는 자연점토에 납, 구리, 아연, 카드뮴의 단일 흡착 시 온도변화에 따른 흙의 구성성분별 흡착거동을 살펴보기 위해 혼합 흡착-연속추출법(combined adsorption-sequential extraction analysis, CASA)을 사용하였다. 실험결과 납과 구리의 경우 약 50%이상의 분배가 탄산염 형태로 나타났고, 카드뮴의 경우 약 80%이상의 분배가 이온교환 형태로 나타났다. 아연의 경우 $25^{\circ}C$이하의 온도에서는 이온교환 형태로의 분배가 약 60%로 나타났고, $40^{\circ}C$이상의 온도에서는 탄산염 형태로의 분배가 50%이상으로 나타났다. 흙의 각 구성성분에 대한 흡착용량의 온도에 따른 영향은 철.망간 산화물과 유기물 형태에서 주로 발생하는 것으로 나타났다. 또한 이온교환 형태를 제외한 모든 형태에 대한 중금속들의 흡착 반응은 온도의 증가에 따라 흡착량이 증가하는 흡열반응(${\Delta}H^0$ >0)인 것으로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.725-730
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• 2013

An investigation of the coordination behavior of sulfur-containing mixed-donor tribenzo-macrocycles $L^1-L^3$ ($L^1$: 20-membered $O_3S_2$, $L^2$: 20-membered $O_2S_3$, and $L^3$: 23-membered $O_4S_2$) with $d^{10}$-metal ($Ag^+$, $Hg^{2+}$, and $Pb^{2+}$) salts is reported. The X-ray structures of five complexes (1-5) with different structural types and stoichiometries, including mono- to dinuclear species have been determined. Reactions of $L^2$ and $L^3$ with the silver(I) salts ($PF_6{^-}$ and $SCN^-$) afforded two dinuclear 2:2 (metal-to-ligand) complexes with different arrangements: a sandwich-type cyclic dinuclear complex $[Ag_2(L^2)_2](PF_6)_2{\cdot}3CH_2Cl_2$ (1) and a linear dinuclear complex $[Ag_2(L^3)_2(SCN)_2]$ (2), in which two monosilver(I) complex units are linked by an Ag-Ag contact. Reactions of $L^1$ and $L^2$ with mercury(II) salts ($SCN^-$ and $Cl^-$) gave a mononuclear 1:1 complexes $[Hg(L^1)(SCN)_2]$ (3) and $[Hg(L^2)Cl_2]$ (4) with anion coordination in both cases. $L^2$ reacts with lead(II) perchlorate to yield a mononuclear sandwich-type complex $[Pb(L^2)_2(ClO_4)_2]$ (5), giving an overall metal coordination geometry of eight with a square antiprism arrangement. From these results, the effects of the donor variation and the anioncoordination ability on the resulting topologies of the soft metal complexes are discussed.

• Journal of Plant Biology
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• 제25권1호
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• pp.21-36
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• 1982

The activity of photosystem II in isolated chloroplast form the leaves of Sedum sarmentosum was measured. The photoreduction rate of DCPIP by photosystem II showed the circadian rhythm with a peak at near midday sample for a continuing fine day and at near afternoon between nidday and sunset sample for a continuing cloudy day in summer. The optimum light intensity of photoreduction by photosystem II in the chloroplast preparation was about 5~9$\times$$10^4$ lux. The saturated light intensity was over 9$\times$$10^1$lux. Photosystem II activity was inhibited by even the lowest concentration of lead. When Pi and ATP of the same concentration as Pb were added to the reaction mixture containing Tris buffer lacking of Pi prior to Pb incubation, photosystem II activity was protected from Pb-inhibiting effect by the pretreament of Pi and ATP. It was assumed that Pb inhibiiton was probably due to one, P-depriving by the precipitates of $Pb_3$ $($Pb_4$)_2$ in the reaction mixture and the other, partially Pb-combing with Pi groups of the active site of photosystem II.

• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1125-1129
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• 2004

This work assesses the potential of natural Analcime Zeolite as an adsorbent for preconcentration of lead (II) traces. Lead is quantitatively retained on 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol by column method with Analcime in the pH range of 5-6.5 and 2 mL $min^{?1}$ flow rate. Lead was removed from the column with 10.0 mL of 4 M hydrochloric acid and was determined by anodic stripping differential pulse voltammetry. 0.5ppb detection limit was obtained and linear dynamic range was 3 to $1.2{\times}10^5$ ppb in final solution with correlation coefficient of 0.999 and relative standard deviation of ${\pm}$ 1.2% (for eight replicate determination of 2.5 ${\mu}g\;mL^{?1}$ of lead). Various parameters such as the effect of pH, flow rate, instrumental conditions and interferences of some ions on the determination of lead have been studied in detail for optimization of conditions. The method was successfully applied for determination of lead in various samples.

• Biomolecules & Therapeutics
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• 제6권3호
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• pp.303-311
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• 1998

The general pharmacological properties of new platinum (II) coordination complexes, SA : [Pt(trans-ι-DACH)(DPPE)] . 2NO$_3$, SB : [Pt(cia-DACH)(DPPP)] 2NO$_3$ and SC : [Pt(cia-DACH)(DPPE)] 2NO$_3$on central nervous, respiratory, cardiovascular and digestive systems were studied in various experimental animals. These platinum (II) anticancer agents had no effects on analgesia, thiopental-induced sleeping time, body temperature, strychnine-induced convulsion, inflammation and local anesthetic action in mice and rats. Intestinal motility, stomach-ulcer induced by serotonin and bile-secretion of rats were not influenced by the dose of 30 mg/kg. However SB and SC induced a mild decrease in heart rate in anesthetized rats. Based on these results, these new platinum (II) complexes may be regarded as a valuable lead compound in the development of new anticancer chemotherapeutic agents with marked antitumor activity and low toxicity.

• 폴리머
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• 제31권2호
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• pp.93-97
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• 2007

Phenyl styryl ketone ligands 1-5 containing different functional groups were synthesized and attached to the aminated poly (styrene-divinvlbenzene) copolymer through diazotization. The coupling of the ligand with polymer was confirmed by FT-IR. The variation of the uptakes of Pb (II) or Cu (II) ions loaded in the prepared polymers (6-10) was examined at different pH values. An increase of metal uptake in the polymers was observed with the increase in pH value in aqueous solution.

• Asian-Australasian Journal of Animal Sciences
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• 제23권11호
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• pp.1482-1489
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• 2010

This study aimed to determine the effects of vitamin C and propolis-supplemented feeds on some blood parameters, lipid peroxidation, and activities of some antioxidant enzymes in broilers exposed to oxidative stress. 360 three-day-old broiler chicks (Ross 308) were randomly divided into four treatment groups each containing 90 animals, including six replicate groups for each treatment. The experimental groups were designated for a 3-42 days period as follows: no supplement to basal ration (Control-Group I); supplement of 500 ppm vitamin C and 200 ppm lead (as lead acetate) to basal ration (Group II); supplement of 1 g/kg propolis and 200 ppm lead (as lead acetate) to basal ration (Group III); and supplement of 200 ppm lead (as lead acetate) to basal ration (Group IV). The highest TG level (86.83 mg/dl) was observed in the lead supplemented group; however, the lowest aspartate aminotransferase (SGOT) level (90.71 IU/L) was observed in the control group (p<0.05). The addition of lead increased the plasma malondialdehyde (MDA) level (p<0.01) compared to other treatments. However, the addition of vitamin C and propolis decreased the plasma MDA level close to control levels. The highest erythrocyte superoxide dismutase (SOD) activity was observed in the lead addition group (p<0.01) while no significant differences were observed for SOD activities of the control, vitamin C +lead, and propolis+lead groups. The plasma reduced glutathione (GSH) activity of the control ($2.30{\mu}mol$/ml) was significantly lower than the lead administered group ($6.20{\mu}mol$/ml) (p<0.01); while this parameter was determined to be similar to other groups. No significant differences were observed between groups for liver GSH activity, but heart GSH activity of the control was significantly higher in comparison to other treatments (p<0.05). To obtain similar antioxidant effects, it is recommend that using propolis (1 g/kg) and vitamin C (500 mg/kg) supplementation in broiler diets may overcome the adverse effects of oxidative stress originating from dietary lead.

• 대한수의학회지
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• 제34권4호
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• pp.801-804
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• 1994

본 실험에서 초산납 투여로 인한 실험초기에 관찰할 수 있는 신경독성은 Schwann 세포의 종창이었다. 종창의 정도를 계측하기 위해 각 실험군 rat의 좌골신경을 횡단 조직표본으로 제작하여 Schwann세포의 두께와 핵의 장경을 측정 비교하였다. 즉 제1실험군은 30일간 0.5% 초산납이 함유된 음료수를 공급하였고 제2실험군은 제1군과 동일한 처리후 일반 실험실 조건에서 30일간 회복되게 하였으며 제3군은 대조군으로 정상 사육하였다. 초산납을 투여한 제1실험에서는 Schwann세포의 두께가 대조군보다 유의한 증가치를 보였는데, 제2실험군은 대조군과 유의한 차이가 없었다. Schwann세포핵의 직경 역시 제1군이 대조군보다 증가되었으나 유의한 차이는 없었다.

• 한국안전학회지
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• 제30권6호
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• pp.7-11
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• 2015

The present study investigates the impact shear strength of thermal aged Sn-3Ag-0.5Cu lead-free solder joints at impact speeds ranging from 0.5 m/s to 2.5 m/s. The specimens were thermal aged for 24, 100, 250 and 1000 hours at $100^{\circ}C$. The experimental results demonstrate that the shear strength of the solder joint decreases with an increase in the load speed and aging time. The shear strength of the solder joint aged averagely decreased by 43% with an increase in the strain rate. For the as-reflowed specimens, the mode II stress intensity factor ($K_{II}$) of interfacial IMC between Sn-3.0Ag-0.5Cu and a copper substrate also was found to decrease from $1.63MPa.m^{0.5}$ to $0.97MPa.m^{0.5}$ in the speed range tested here. The degradations in the shear strength and fracture toughness of the aged solder joints are mainly caused by the growth of IMC layers at the solder/substrate interface.