• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1801-1808
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• 2006

The interaction between whey carrier protein $\beta$-lactoglobulin type A and B (BLG-A and -B) and 2,2'-bipyridin n-hexyl dithiocarbamato Pd(II) nitrate (BPHDC-Pd(II)), a new heavy metal complex designed for anticancer property, was investigated by fluorescence spectroscopy combined with chemometry and circular dichroism (CD) techniques. A strong fluorescence quenching reaction of BPHDC-Pd(II) to BLG-A and -B was observed. Hence, BPHDC-Pd(II) complex can be bound to both BLG-A and -B, and quench the fluorescence spectra of the proteins. The quenching constant was determined using the modified Stern-Volmer equation. The binding parameters were evaluated by fluorescence quenching method. The results of binding study provided evidences presence of two and three sets of binding sites on the BLG-B and -A, respectively, for BPHDC-Pd(II) complex. Using fluorescence spectroscopy and chemometry, the ability of BLG-A and -B to form an intermediate upon interaction with BPHDC-Pd(II) complex was assessed. CD studies displayed that under influence of different concentrations of BPHDC-Pd(II) complex, the regular secondary structure of BLG-B had no significant changes, whereas for BLG-A a transition from $\alpha$-helix to $\beta$-structure was appeared. The results for both of BLG-A and -B displayed that BPHDC-Pd(II) complex can induce a conformational transition from the native form to an intermediate state with a slightly opened conformation, which is detectable with chemometry analyses.

• 한국농공학회논문집
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• 제60권5호
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• pp.105-113
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• 2018

In this study physical and chemical characteristics of rice straw ash (RSA) were analyzed in agricultural by-products such as the characteristics of soil pH, electric conductivity (EC), total phosphorus (T-P), available phosphate (Avail-P), and cation exchange capacity (CEC). The results showed that RSA is of mainly C in 95.74% and followed by Si > Al > P > Mg > K > Ca. The pH of RSA was high near 11 and the T-P concentration was $2,322.38{\pm}10.35mg/kg$. The specific surface area of RSA was $123.50m^2/g$, which was much lower than that of biochar. The X-ray diffraction (XRD) analysis indicated that RSA were C and Si based crystalline. TCLP and KSLT test results implied that the heavy metal concentrations were below the environmental standards and would not impose the risks. T-P concentration increased from $225.59{\pm}12.69mg/kg$ to $593.39{\pm}17.36mg/kg$ along with RSA mixing ratio to soil from 0% to 15%. Both pH and EC values were increased with the increase of RSA ratio. The changes in Avail-P and CEC were not when RSA mixing ratio was 1%. whereas the Avail-P concentration was slightly increase when the mixing ratio was more than 5%. Additional investigation considering receiving soil characteristics based on the results of this study would help effective application of RSA to soil.

• Molecules and Cells
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• 제28권5호
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• pp.479-487
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• 2009

Glutathione reductase (GR) is an enzyme that recycles a key cellular antioxidant molecule glutathione (GSH) from its oxidized form (GSSG) thus maintaining cellular redox homeostasis. A recombinant plasmid to overexpress a GR of Brassica rapa subsp. pekinensis (BrGR) in E. coli BL21 (DE3) was constructed using an expression vector pKM260. Expression of the introduced gene was confirmed by semi-quantitative RT-PCR, immunoblotting and enzyme assays. Purification of the BrGR protein was performed by IMAC method and indicated that the BrGR was a dimmer. The BrGR required NADPH as a cofactor and specific activity was approximately 458 U. The BrGR-expressing E. coli cells showed increased GR activity and tolerance to $H_2O_2$, menadione, and heavy metal ($CdCl_2$, $ZnCl_2$ and $AlCl_2$)-mediated growth inhibition. The ectopic expression of BrGR provoked the co-regulation of a variety of antioxidant enzymes including catalase, superoxide dismutase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase. Consequently, the transformed cells showed decreased hydroperoxide levels when exposed to stressful conditions. A proteomic analysis demonstrated the higher level of induction of proteins involved in glycolysis, detoxification/oxidative stress response, protein folding, transport/binding proteins, cell envelope/porins, and protein translation and modification when exposed to $H_2O_2$ stress. Taken together, these results indicate that the plant GR protein is functional in a cooperative way in the E. coli system to protect cells against oxidative stress.

• 한국구조물진단유지관리공학회 논문집
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• 제14권1호
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• pp.109-116
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• 2010

물유리계 그라우팅 공법은 침투주입 그라우팅으로 자주 적용되고 있으나, 시간경과에 따른 내구성 저하와 환경에 부정적 영향에 대한 문제가 부각되고 있다. 이에 마이크로시멘트계 무기질 재료의 ENG 공법이 이러한 물유리계 그라우팅 공법의 문제점을 극복하면서 우수한 침투성을 목표로 하여 개발되었다. ENG의 적용성을 파악하기 위해 체적변형시험, 용탈실험, 일축압축실험, 실내 투수실험 및 현장투수실험 그리고 중금속검출실험을 실시하였다. 그 결과 체적변형, 용탈량, 일축압축강도는 물유리 공법보다 월등히 우수하였으며, 투수실험에 있어서도 차수효과가 나타났다. 또한 중금속 검출량도 미미하여 환경에 부정적인 효과도 적을 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.274-282
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• 2019

Mercury-resistant ($Hg^R$) bacteria were isolated from heavy metal polluted wastewater and soil collected near to tanneries of district Kasur, Pakistan. Bacterial isolates AZ-1, AZ-2 and AZ-3 showed resistance up to $40{\mu}g/ml$ against mercuric chloride ($HgCl_2$). 16S rDNA ribotyping and phylogenetic analysis were performed for the characterization of selected isolates as Bacillus sp. AZ-1 (KT270477), Bacillus cereus AZ-2 (KT270478) and Bacillus cereus AZ-3 (KT270479). Phylogenetic relationship on the basis of merA nucleotide sequence confirmed 51-100% homology with the corresponding region of the merA gene of already reported mercury-resistant Gram-positive bacteria. The merE gene involved in the transportation of elemental mercury ($Hg^0$) via cell membrane was cloned for the first time into pHLV vector and transformed in overexpressed C43(DE3) E. coli cells. The recombinant plasmid (pHLMerE) was expressed and the native MerE protein was obtained after thrombin cleavage by size exclusion chromatography (SEC). The purification of fusion/recombinant and native protein MerE by Ni-NTA column, dialysis and fast protein liquid chromatography (FPLC/SEC) involved unfolding/refolding techniques. A small-scale reservoir of wastewater containing $30{\mu}g/ml$ of $HgCl_2$ was designed to check the detoxification ability of selected strains. It resulted in 83% detoxification of mercury by B. cereus AZ-2 and B. cereus AZ-3, and 76% detoxification by Bacillus sp. AZ-1 respectively (p < 0.05).

• 대한본초학회지
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• 제36권1호
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• pp.41-49
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• 2021

Objective : Citrus unshiu peel (Citri Unshius Pericarpium) has been prescribed to suppress coughing and phlegm in Korean medicine. In this study, the effect of ethanol extract of Citrus unshiu peel (CEE) on apoptosis was investigated using cadmium chloride (CdCl2) treated HepG2 cells. Methods : CEE was prepared by extracting 300 g of Citri Unshius Pericarpium in 3 L of ethanol for 72 h. Apoptosis was determined by the TUNEL assay. The mitochondrial membrane potential (MMP) was monitored using the membrane-permeable fluorescent dye Rh123. The expression level of each protein was monitored by Western blot analysis. Results : CEE protected HepG2 cells from apoptosis as determined by the TUNEL assay. A decrease in MMP was observed in cells exposed to cadmium, indicating that mitochondria are involved in the induction of apoptosis. However, CEE recovered the reduction in MMP caused by cadmium. In addition, decreased expression of B-cell lymphoma 2 (Bcl-2), procaspase, and poly(ADP-ribose) polymerase (PARP) by cadmium was increased by CEE. The anti-apoptotic effect of CEE was found to be associated with inhibition of JNK and p38 phosphorylation when examining the expression of phosphorylated MAPK by Western blot. Conclusion : This study showed that CEE exerted anti-apoptotic effects in cadmium-induced HepG2 cells by inhibiting the reduction of MMP and changes in the expression level of apoptotic proteins. These results suggest the potential for CEE to be used for heavy metal-induced liver damage.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.3095-3105
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• 2022

Solid Microencapsulated Fuel (SMF) is a type of solid fuel rod design that disperses TRISO coated fuel particles directly into a kind of matrix. SMF is expected to provide improved performance because of the elimination of cladding tube and associated failure mechanisms. This study focused on the neutronics and some of the fuel cycle characteristics of SMF by using OpenMC. Two kinds of SMFs have been designed and evaluated - fuel particles dispersed into a silicon carbide matrix and fuel particles dispersed into a zirconium matrix. A 7×7 fuel assembly with increased rod diameter transformed from the standard NHR200-II 9×9 array was also introduced to increase the heavy metal inventory. A preliminary study of two kinds of burnable poisons (Erbia & Gadolinia) in two forms (BISO and QUADRISO particles) was also included. This study found that SMF requires about 12% enriched UN TRISO particles to match the cycle length of standard fuel when loaded in NHR200-II, which is about 7% for SMF with increased rod diameter. Feedback coefficients are less negative through the life of SMF than the reference. And it is estimated that the average center temperature of fuel kernel at fuel rod centerline is about 60 K below that of reference in this paper.

• 한국방사선학회논문지
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• 제16권4호
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• pp.419-425
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• 2022

의료현장에서는 방사선으로부터 인체를 보호하기 위하여 납 앞치마를 사용한다. 하지만 납은 중금속으로 인체 및 환경에 유해성을 나타내고 있어 다양한 차폐체 개발이 진행되고 있다. 본 연구에서는 납과 원자번호가 비슷한 비스무트를 새로운 소재로 설정하고 같은 에너지 영역에서 두께에 따른 흡수율을 몬테카를로(Monte Carlo) 시뮬레이션을 통해 분석하였다. 납 차폐체 두께가 0.25 mm인 경우 비스무트 두께가 0.3 mm, 납 0.50 mm인 경우 비스무트 0.60 mm, 납 0.75 mm인 경우 비스무트 0.90 mm에서 유사한 경향성을 확인할 수 있었다. 따라서 차폐체의 소재로 납을 비스무트로 대체하여 사용하는 데는 무리가 없을 것으로 사료된다.

• 분석과학
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• 제19권4호
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• pp.285-289
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• 2006

본 연구에서는 산 표면 처리한 입상 활성탄(GAC)과 활성 탄소섬유(ACF)에 의한 $Pb^{2+}$와 $Ni^{2+}$ 이온의 흡착 특성을 고찰하였다. 산 표면 처리용액으로는 1.0 M 질산 용액을 사용하였다. GAC와 ACF의 표면특성분석은 pH, 등전점(pHpzc), 그리고 원소분석기를 사용하였으며, 비표면적과 기공구조는 77K에서 $N_2$ 등온흡착 방법으로 측정하였다. 본 실험결과 GAC 와 ACF를 산으로 표면 처리한 경우 산소를 포함한 작용기가 증가하였다. 이처럼 산 표면 처리에 의해 증가된 표면 작용기에 따른 GAC 및 ACF의 기공이 막힘에도 불구하고, acidic-ACF > untreated-ACF > acdic-GAC > untreated-GAC 순으로 중금속 흡착능이 증가하였다.

• 한국수산과학회지
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• 제57권3호
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• pp.203-208
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• 2024

Fifteen cultured frozen abalone Haliotis discus hannai samples were purchased from supermarkets, traditional markets, online markets, and processing factories throughout Korea for the safety assessment of microbiological and chemical hazards. Sanitary-indicative (total viable bacteria, coliforms, and Escherichia coli) and pathogenic (Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Clostridium perfringens, and Enterohemorrhagic E. coli) bacterial contamination levels were assessed quantitatively or qualitatively. Additionally, heavy metal content (lead, cadmium, and total mercury) and radioactivity (¹³⁴CS+¹³⁷CS, ¹³¹I) were quantitatively assessed. The total viable bacterial count was 4.3×10² CFU/g, while coliform count was 50 CFU/g. E. coli was not detected in any of the samples (count < 10 CFU/g). All six pathogenic bacteria tested negative qualitatively. The average lead, cadmium, and total mercury contamination levels in the cultured frozen abalone were 0.100±0.057, 0.145±0.061, and 0.015±0.001 mg/kg, respectively. Moreover, none of the samples were radioactive. According to the results of this study, cultured frozen abalones distributed in all types of markets were safe from all microbiological and chemical hazards.