• 상하수도학회지
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• 제28권2호
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• pp.207-215
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• 2014

Wastewater containing heavy metals such as copper (Cu) and nickel (Ni) is harmful to humans and the environment due to its high toxicity. Crystallization in a fluidized bed reactor (FBR) has recently received significant attention for heavy metal removal and recovery. It is necessary to find optimum reaction conditions to enhance crystallization efficacy. In this study, the effects of crystallization reagent and pH were investigated to maximize crystallization efficacy of Cu-S and Ni-S in a FBR. CaS and $Na_2S{\cdot}9H_2O$ were used as crystallization reagent, and pH were varied in the range of 1 to 7. Additionally, each optimum crystallization condition for Cu and Ni were sequentially employed in two FBRs for their selective removal from the mixture of Cu and Ni. As major results, the crystallization of Cu was most effective in the range of pH 1-2 for both CaS and $Na_2S{\cdot}9H_2O$ reagents. At pH 1, Cu was completely removed within five minutes. Ni showed a superior reactivity with S in $Na_2S{\cdot}9H_2O$ compared to that in CaS at pH 7. When applying each optimum crystallization condition sequentially, only Cu was firstly crystallized at pH 1 with CaS, and then, in the second FBR, the residual Ni was completely removed at pH 7 with $Na_2S{\cdot}9H_2O$. Each crystal recovered from two different FBRs was mainly composed of CuxSy and NiS, respectively. Our results revealed that Cu and Ni can be selectively recovered as reusable resources from the mixture by controlling pH and choosing crystallization reagent accordingly.

• 한국초지조사료학회지
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• 제36권3호
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• pp.237-242
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• 2016

Copper (Cu) is a necessary microelement for plants. However, high concentrations of Cu are toxic to plants that change the regulation of several stress-induced proteins. In this study, an annealing control primer (ACP) based approach was used to identify differentially expressed Cu-induced genes in alfalfa leaves. Two-week-old alfalfa plants (Medicago sativa L.) were exposed to Cu for 6 h. Total RNAs were isolated from treated and control leaves followed by ACP-based PCR technique. Using GeneFishing ACPs, we obtained several genes those expression levels were induced by Cu. Finally, we identified several genes including UDP-glucuronic acid decarboxylase, transmembrane protein, small heat shock protein, C-type cytochrome biogenesis protein, mitochondrial 2-oxoglutarate, and trans-2,3-enoyl-CoA reductase in alfalfa leaves. These identified genes have putative functions in cellular processes such as cell wall structural rearrangements, transduction, stress tolerance, heme transport, carbon and nitrogen assimilation, and lipid biosynthesis. Response of Cu-induced genes and their identification in alfalfa would be useful for molecular breeding to improve alfalfa with tolerance to heavy metals.

• 한국응용과학기술학회지
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• 제25권2호
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• pp.168-174
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• 2008

This study is focused on the antimicrobial activity of cyanobacteria Microcystis aeruginosa by the reduction and oxidation reaction of copper and zinc alloy metal fiber filter. Cu/Zn ion is easily makes radicals with molecular hydroperoxide. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper and zinc alloy metal fiber is detected in the cyanobacteria solution as 0.5 ppm, and that of zinc ion is 0 ppm respectively. Zinc ion is figured to form a hydroxide in the cyanobacteria solution and precipitated to form a sludge. The concentration of chlorophyll-a in the cyanobacteria solution was proved to be the index of antimicrobial level of Microcystis aeruginosa.

• 한국환경과학회지
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• 제24권12호
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• pp.1591-1600
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• 2015

The response of the freshwater microalga, Chlorella vulgaris, to heavy metal stress was examined based on chlorophyll fluorescence analysis to assess the toxic effects of heavy metals in freshwater ecosystems. When toxic effects were analyzed using regular chlorophyll fluorescence analysis, photosystem II activity($F_v/F_m$) decreased significantly when exposed to $Cu^{2+}$ and $Hg^{2+}$ for 12 h, and decreased in the order of $Hg^{2+}>Cu^{2+}>Cd^{2+}>Ni^{2+}$ when exposed for 24h. The effective photochemical quantum yield(${\phi}{\prime}_{PSII}$), chlorophyll fluorescence decrease ratio($R_{Fd}$), minimal fluorescence yield($F_o$), and non-photochemical quenching(NPQ), but not photochemical quenching(qP), responded sensitively to $Hg^{2+}$, $Cu^{2+}$, and $Cd^{2+}$. These results suggest that $F_v/F_m$, as well as ${\phi}{\prime}_{PSII}$, $R_{Fd}$, $F_o$, and NPQ could be used to assess the effects of heavy metal ions in freshwater ecosystems. However, because many types of heavy metal ions and toxic compounds co-occur under natural conditions, it is difficult to assess heavy metal toxicity in freshwater ecosystems. When Chlorella was exposed to heavy metal ions for 12 or 24h, $F_v/F_m$ and maximal fluorescence yield($F_m$) changed in response to $Hg^{2+}$ and $Cu^{2+}$ based on image analysis. However, assessing quantitatively the toxic effects of several heavy metal ions is challenging.

• Journal of Applied Biological Chemistry
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• 제42권4호
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• pp.169-174
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• 1999

Arabidopsis AHL gene contains 4 exons encoding a putative protein highly homologous to the yeast salt-sensitive enzyme HAL2, a 3'(2'),5'-bisphosphate nucleotidase involving in reductive sulfate assimilation. AHL cDNA complemented yeast met22 (hal2) mutant. AHL fusion protein expressed in E. coli exhibited $Mg^{2+}$-dependent, 3'-phosphoadenosine 5'-phosphate (PAP)-specific phosphatase activity. $Li^+,\;Na^+,\;K^+$ and $Ca^{2+}$ ions inhibit the enzyme activity by competing with $Mg^{2+}$ for the active site of the enzyme. The enzyme activity was also sensitive to ${\mu}M$ concentrations of toxic heavy metal ions such as $Cd^{2+},\;Cu^{2+}$ and $Zn^{2+}$, but was not recovered by addition of more $Mg^{2+}$ ions, suggesting that these ions inactivate the enzyme with a mechanism other than competition with $Mg^{2+}$ ions. Inhibition of the AHL enzyme activity may result in accumulation of PAP, which is highly toxic to the cell. Thus, the AHL enzyme could be one of the intial targets of heavy metal toxicity in plants.

• The Journal of Advanced Prosthodontics
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• 제6권3호
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• pp.215-223
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• 2014

PURPOSE. This study aimed to develop a copper-aluminium-nickel alloy which has properties comparable to that of dental alloys used for dental post and core applications with the reasonable cost. MATERIALS AND METHODS. Sixteen groups of experimental copper alloys with variants of 3, 6, 9, 12 wt% Al and 0, 2, 4, 6 wt% Ni were prepared and casted. Their properties were tested and evaluated. The data of thermal, physical, and mechanical properties were analyzed using the two-way ANOVA and Tukey's test (${\alpha}$=0.05). The alloy toxicity was evaluated according to the ISO standard. RESULTS. The solidus and liquidus points of experimental alloys ranged from $1023^{\circ}C$ to $1113^{\circ}C$ and increased as the nickel content increased. The highest ultimate tensile strength ($595.9{\pm}14.2$ MPa) was shown in the Cu-12Al-4Ni alloy. The tensile strength was increased as the both elements increased. Alloys with 3-6 wt% Al exhibited a small amount of 0.2% proof strength. Accordingly, the Cu-9Al-2Ni and Cu-9Al-4Ni alloys not only demonstrated an appropriate modulus of elasticity ($113.9{\pm}8.0$ and $122.8{\pm}11.3$ GPa, respectively), but also had a value of 0.2% proof strength ($190.8{\pm}4.8$ and $198.2{\pm}3.4$ MPa, respectively), which complied with the ISO standard requirement (>180 MPa). Alloys with the highest contents of nickel (6 wt% Ni) revealed a widespread decolourisation zone (5.0-5.9 mm), which correspondingly produced the largest cell response, equating positive control. CONCLUSION. The copper alloys fused with 9 wt% Al and 2-4 wt% Ni can be considered for a potential use as dental post and core applications.

• 대한화학회지
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• 제54권5호
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• pp.506-514
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• 2010

benzoylisothiocyanate 와 아스파르트산 [BATA] (1), 글루탐산 [BATG] (2), 메티오닌 [BATM] (3), 루신 [BATL] (4), 및 트립토판 [BATT] (5) 등의 다양한 아미노산을 반응시켜 일련의 새로운 리간드인 N-[(benzoylamino)-thioxomethyl]-amino acid (HL)를 합성하였다. 이들 리간드의 특성을 원소분석, IR 및 NMR로 규명하였다. 이러한 리간드 (6-8)의 몇가지 전이금속 착물을 제조하여[M = Cu(II), Co(II), 또는 Ni(II)] 원소분석, IR 및 $^1H$ NMR을 통하여 특성을 규명하였다. 항균성에 대한 연구 결과 모든 리간드가 항균 활성을 보이지 않는 반면, ($ML_2$) 착물; [M=Cu(II),Co(II), 또는 Ni(II)]은 (Gram -ive) Escherichia (NCTC5933) 및 (Gram +ive) Staphylococcus (NCTC6571)에 대해 항균 활성을 보였으며 또한 (BALB/C) 알비노 쥐에 대해 독성을 보이지 않았다.

• 자원환경지질
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• 제48권3호
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• pp.261-271
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• 2015

본 총설 논문에서는 다양한 급성독성법을 이용하여 중금속, 나노입자, 중금속 오염 토양에 의한 영향 평가 결과를 소개하였다. 평가는 씨앗발아, 생물발광, 효소활성 및 유전자 변이 평가법을 이용하였으며, 오염물 종류 및 방법에 따라 상이한 민감도를 보였다. 씨앗의 경우에는 상추(Lactucus)와 알타리무(Raphanus)가 대체적으로 높은 민감도를 보였다. 단일 금속 노출에서는 일반적으로 As(III)가 높은 독성을 나타내었다. As(III) 1 mg/L 조건에서 높은 유전자변이(MR=5.1)가 관찰되었다. 혼합 중금속에 대한 영향은 명확한 경향을 찾기 어려웠지만, 씨앗 발아의 경우에는 상승 효과가 보편적으로 관찰되었다. 중금속 오염 토양에 대한 평가에서는 시료별 총중금속 농도와 독성 영향 간의 상관성을 예측하기는 어려웠다. 일반적으로 나노입자의 씨앗발아에 근거한 영향은 다음의 순서로 조사되었다: CuO > ZnO > NiO > $TiO_2$, $Fe_2O_3$, $Co_3O_4$. 특히 $TiO_2$, $Fe_2O_3$와 $Co_3O_4$는 최대 노출 농도 1,000 mg/L 농도에서도 뚜렷한 영향을 나타내지 않았다. 다양한 독성 생물검정법에 대한 통합 자료는 향후 다양한 오염물 기초 독성평가에 유용하게 사용할 수 있을 것이다.

• Ecology and Resilient Infrastructure
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• 제4권1호
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• pp.63-70
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• 2017

가축용 항생제로 널리 사용되는 Tetracycline (TC)군은 주로 가축 분뇨를 통하여 환경에 퍼지게 된다. TC는 환경 내에서 중금속 양이온과의 리간드 결합을 통해 토양으로의 흡착량과 그 이동성이 변화되리라 예측된다. 그러나 지금까지 수용액 내에서 토양 외 반응을 통해 확인되었고 토양 내에서 식물에 대한 영향 평가는 미비한 실정이다. 본 연구의 목적은 토양 내 구리가 TC와 반응하여 TC에 의한 식물 독성에 미치는 영향을 확인하는데 있다. 본 실험은 토양에 $750mg\;kg^{-1}$의 TC와 각각 0, 2.5, 7.5, $17.5mg\;kg^{-1}$의 $CuSO_4$를 처리한 후, 처리된 토양에 상추를 재배하여 처리 농도에 따른 상추의 성장 정도를 비교하였다. 실험 결과 상추에 유의한 독성이 나타나는 것으로 확인된 $750mg\;kg^{-1}$의 TC가 처리된 토양에서 구리의 처리가 상추에 발현되었던 독성을 저감시키는 것을 확인하였다.

• 한국패류학회지
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• 제31권2호
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• pp.151-158
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• 2015

본 연구는 구리에 노출된 꼬막, Tegillarca granosa의 생존율, 호흡율 및 기관계의 반응을 알아보고자 하였다. 실험기간은 4주였으며, 실험구는 대조구와 구리 노출구 3개 (0.125, 0.250 and 0.500 mg/L) 였다. 실험 결과 구리는 꼬막의 생존율과 호흡률의 저하 및 기관계의 조직학적 변성을 유도하는 것이 확인되었다. 노출 종말점에서 0.500 mg/L의 구리 노출구에서 사망률은 66.7%였으며, 호흡률은 대조구에 비해 18.2%로 감소하였다. 기관계의 조직학적 분석 결과, 외투막 상피층과 결합조직층의 변성, 아가미 새엽 상피세포의 위축과 측면섬모의 소실, 발에서는 상피층의 붕괴, 점액의 산성화 및 혈림프동의 확장과 근섬유 다발의 변성을 나타냈다. 소화맹낭의 소화선세관에서는 호염기성세포와 상피세포의 위축 및 붕괴가 확인되었다.