• 환경위생공학
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• 제23권2호
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• pp.1-18
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• 2008

The tetrachloroethylene (PCE) dehalogenase of Clostridium bifermentans DPH-1 (a halorespiring organism) was purified, cloned, and sequenced. This enzyme is a homodimer with a molecular mass of ca. 70 kDa and exhibits dehalogenation of dichloroethylene isomers along with PCE and trichloroethylene (TCE). Broad range of substrate specificity for chlorinated aliphatic compounds (PCE, TCE, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,1-dichloroethylene, 1,2-dichloropropene, and 1,1,2-trichloroethane) for this enzyme was also observed. A mixture of propyl iodide and titanium citrate caused a light-reversible inhibition of enzymatic activity suggesting the involvement of a corrinoid cofactor. A partial sequence (81 bp) of the encoding gene for PCE dehalogenase was amplified and sequenced with degenerateprimers designed from the N-terminal sequence (27 amino acid residues). Southern analysis of C. bifermentans genomic DNA using the polymerase chain reaction product as a probe revealed restriction fragment bands. A 5.0 kb ClaI fragment, harboring the relevant gene (designated pceC) was cloned (pDEHAL5) and the complete nucleotide sequence of pceC was determined. The gene showed homology mainly with microbial membrane proteins and no homology with any known dehalogenase, suggesting a distinct PCE dehalogenase. So, C. bifermentans could play some important role in the initial breakdown of PCE and other chlorinated aliphatic compounds in sites contaminated with mixtures of halogenated substances.

• 미생물학회지
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• 제23권4호
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• pp.265-270
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• 1985

Brevibacterium flavum과 Corllnebac ter ium glutamicum세포로부터의 원형질쳐l 형성과정, 형성된 원형질체의 미세구조, 이들 원형질체간의 융합 및 세포벽 재생을 투과전자현미경을 사용하여 관찰하였다. 원형질쳐1의 형성과 정은 특이하게 관찰되었다. 즉, penicillin G와 lysozyme의 작용을 받아 세포벽의 한 부위가 파괴되어 생긴 細孔응 통하여 원형질이 빠져나가 구형의 원형질체를 형성하였닥 융합과정에서는 원형질체들이 서로 접촉하여 접촉부꾀 를 형성하고 이어서 이 부위의 셰포막이 얼부 소실되며 양 원형질쳐1간에 내부의 울질들이 이동하였다 융합 원 행질체들은 비융합 원형질체에 비하여 세포벽의 재생이 다소 더디게 일어나는 것으로 관찰되었으며, 융합 원형질 쳐l들이 비융합 원형질체들 보다 그 크기가 월등히 컸다.

• Molecules and Cells
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• 제45권11호
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• pp.806-819
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• 2022

Synaptic accumulation of α-synuclein (α-Syn) oligomers and their interactions with VAMP2 have been reported to be the basis of synaptic dysfunction in Parkinson's disease (PD). α-Syn mutants associated with familial PD have also been known to be capable of interacting with VAMP2, but the exact mechanisms resulting from those interactions to eventual synaptic dysfunction are still unclear. Here, we investigate the effect of α-Syn mutant oligomers comprising A30P, E46K, and A53T on VAMP2-embedded vesicles. Specifically, A30P and A53T oligomers cluster vesicles in the presence of VAMP2, which is a shared mechanism with wild type α-Syn oligomers induced by dopamine. On the other hand, E46K oligomers reduce the membrane mobility of the planar bilayers, as revealed by single-particle tracking, and permeabilize the membranes in the presence of VAMP2. In the absence of VAMP2 interactions, E46K oligomers enlarge vesicles by fusing with one another. Our results clearly demonstrate that α-Syn mutant oligomers have aberrant effects on VAMP2-embedded vesicles and the disruption types are distinct depending on the mutant types. This work may provide one of the possible clues to explain the α-Syn mutant-type dependent pathological heterogeneity of familial PD.

• Membrane and Water Treatment
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• 제15권1호
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• pp.41-50
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• 2024

Presence of hazardous dyes in water cause considerable risks to the human health and environment due to their potential toxicity and ecological disruptions. Therefore, in the present research, to suggest an alternative method for the retention of toxic Azocarmine G (ACG) dye from aqueous media, natural and H₂SO₄-modified acacia sawdust were performed for the first time as low-cost and efficient adsorbents. Based on batch experiments, it was determined that the best conditions for the developed dye retention process were an initial pH of 2.0 and an equilibrium time of 240 min. Analysis of the data using both pseudo-first order and pseudo-second order kinetic models showed that the retention of ACG onto the adsorbents predominantly occurred through chemical adsorption. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were employed to provide insights into the interaction between the adsorbate and adsorbent and the mechanism of the adsorption process. Maximum monolayer adsorption capacities of natural and H₂SO₄-modified acacia sawdust were determined as 28.01 and 64.90 mg g^-1, respectively by Langmuir isotherm model. Results of the study clearly indicated that the modification of acacia sawdust with H₂SO₄ leads to a substantial increase in the adsorption performance of anionic dyes.

• 공업화학
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• 제25권5호
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• pp.544-547
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• 2014

본 연구에서는 효소면역 분석법(enzyme-linked immunosorbent assay)과 면역크로마토그래픽 기법을 결합하여 Legionella pneumophila 검출을 위한 면역스트립을 제작하였다. 면역스트립은 4종의 멤브레인을 이용하여 제작하였다. 니트로셀룰로오스 멤브레인은 포획항체를 고정화하여 신호 발생을 일으키기 위해 사용되었고, 두 종류의 유리섬유 멤브레인은 각각 중합체 패드와 시료주입 패드로 사용되었다. 셀룰로오스 멤브레인은 모세관 현상으로 시료흐름을 유도하는 흡수 패드로 이용하였다. 샌드위치 면역반응과 효소반응에 의해 30 min 이내에 생성된 발색신호는 정성 및 정량 분석이 가능하였다. 분석조건 하에서 육안에 의한 정성 검출뿐 아니라, $1.3{\times}10^3-1.3{\times}10^6CFU/mL$ 범위의 L. pneumophila 농도를 디지털카메라와 자체 제작된 소프트웨어를 이용하여 정량적으로 분석할 수 있었다.

• 대한화학회지
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• 제29권2호
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• pp.137-143
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• 1985

액체막형 구리이온 선택성 전극의 제작과 전위차적정에의 응용을 연구하였다. 액체 이온교환막은 수용액속의 Cu(II)을 1-(2-pyridylazo)-2-naphthol/nitrobenzene 용액 속으로 추출하여 만들었다. 액체 이온교환막 위에 HAc-NaAc 용액으로 완충된 $1.00 {\times} 10^{-3}M\;Cu(NO_3)_2$ 용액을 채우고 Ag/AgCl 내부 기준전극을 담그었다. 이 이온선택성 전극은 $1.00 {\times} 10^{-6}$ ~ $1.00 {\times} 10^{-3}$M Cu(II) 농도 범위에서 nerstian response를 보여주었다. 가장 적절한 이온교환체의 농도는 $1.00 {\times} 10^{-4}$M이었다. 여러가지 금속이온에 대한 이온선택성 전극의 선택계수를 측정하였다. EDTA를 적정제로 하여 Cu(II)에 대한 전위차적정에 응용하였다.

• 한국수소및신에너지학회논문집
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• 제28권2호
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• pp.156-165
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• 2017

This study quantitatively assessed the environmental impacts of fuel cell (FC) systems by performing life cycle assessment (LCA) and analyzed their energy efficiencies based on energy return on investment (EROI) and electrical energy stored on investment (ESOI). Molten carbonate fuel cell (MCFC) system and polymer electrolyte membrane fuel cell (PEMFC) system were selected as the fuel cell systems. Five different paths to produce hydrogen ($H_2$) as fuel such as natural gas steam reforming (NGSR), centralized naptha SR (NSR(C)), NSR station (NSR(S)), liquified petroleum gas SR (LPGSR), water electrolysis (WE) were each applied to the FCs. The environmental impacts and the energy efficiencies of the FCs were compared with rechargeable batteries such as $LiFePO_4$ (LFP) and Nickel-metal hydride (Ni-MH). The LCA results show that MCFC_NSR(C) and PEMFC_NSR(C) have the lowest global warming potential (GWP) with 6.23E-02 kg $CO_2$ eq./MJ electricity and 6.84E-02 kg $CO_2$ eq./MJ electricity, respectively. For the impact category of abiotic resource depletion potential (ADP), MCFC_NGSR(S) and PEMFC_NGSR(S) show the lowest impacts of 7.42E-01 g Sb eq./MJ electricity and 7.19E-01 g Sb eq./MJ electricity, respectively. And, the energy efficiencies of the FCs are higher than those of the rechargeable batteries except for the case of hydrogen produced by WE.

• 공업화학
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• 제2권4호
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• pp.399-410
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• 1991

저장 안정한 액체염료의 제조를 위하여 새로운 분리 기술을 도입하였다. 액체염료에 함유된 무기염의 종류, 농도 및 액체염료의 저장기간이 염료분자의 집합(aggregation)과 안정성에 미치는 영항을 실험측정하였다. 높은 염농도에 의한 염료분자의 집합의 형성을 방지하지 위해 표면처리한 중공사막을 이용한 역확산(counter diffusion)법을 도입하여 액체염료에 함유된 염을 선택적으로 제거하였다. 역확산에 의한 염의 제거 효율은 1회 통과에 5-20%였고 염과 염료의 분리비는 10-700으로 매우 큰 값을 갖는 반면 염료의 손실율은 0.4% 이하였다. 모델식을 이용하여 구한 염과 염료의 막에 대한 물질전달 계수 ($U_{M,Na}$, $U_{M,Dye}$)는 표면처리한 경우에 각각 2.75와 $0.72l/m^2/hr$의 값을 나타내어 염과 염료의 혼합액에서 염의 선택적 분리가 가능함을 보여주었다. 또한 탈거수 및 공급액의 유속, 막의 막힘현상이 염의 제거 효율에 미치는 영향을 연구하였다.

• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.21-29
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• 2010

The phenolic compounds are a major contaminant class often found in industrial wastewaters and the biological treatment is an alternative tool commonly employed for their removal. In this sense, monitoring microbial community dynamics is crucial for a successful wastewater treatment. This work aimed to monitor the structure and activity of the bacterial community during the operation of a laboratory-scale continuous submerged membrane bioreactor (SMBR), using PCR and RT-PCR followed by denaturing gradient gel electrophoresis (DGGE) and 16S rRNA libraries. Multivariate analyses carried out using DGGE profiles showed significant changes in the total and metabolically active dominant community members during the 4-week treatment period, explained mainly by phenol and ammonium input. Gene libraries were assembled using 16S rDNA and 16S rRNA PCR products from the fourth week of treatment. Sequencing and phylogenetic analyses of clones from the 16S rDNA library revealed a high diversity of taxa for the total bacterial community, with predominance of Thauera genus (ca. 50%). On the other hand, a lower diversity was found for metabolically active bacteria, which were mostly represented by members of Betaproteobacteria (Thauera and Comamonas), suggesting that these groups have a relevant role in the phenol degradation during the final phase of the SMBR operation.

• 대한화학회지
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• 제16권5호
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• pp.304-313
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• 1972

溶解된 粒子의 이온量 또는 分子量을 決定하는 方法으로서의 透膜法에는 裝置의 未備點과 實驗方法의 改良되어야 할 點이 아직 남아 있으므로 우선 이들을 改善하여 補完하였다. 透析簡에 膜을 密着시킬수 있도록 鐵製링을 開發하였다. 透析液과 外部液의 水準을 0.02mm의 精度로 一致調節하고 維持시킴으로써 渗透 및 濾過效果를 最小限度로 抑制시켰다. 두 液의 攪拌速度를 任意의 定速度로 變更하여 그 攪拌量을 一定하게 維持할 수 있도록 하였으며, 그 溫度를 透析其間中 ${\pm}0.01^{\circ}C$의 精度로 一致維持시킬수 있도록 하였다. 透析期間中 透析液의 부피變化를 -1.62 ~ +0.92%範圍로 좁혔으며, 渗透 및 濾過效果와 膜孔의 크기와의 關係를 追究하여 最適透析時間을 究明하였다.