• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
• /
• pp.394-397
• /
• 2006

Hydrogeologic and hydrochemlcat conditions of two uncontrolled landfills without reliable underlying liners, leachate collection and treatment systems were compared. With similar weather conditions, spatial distribution and temporal variations of contaminants of concern and redox parameters were different for the two landfills. These differences are highly associated with ages and hydrogeologic settings of the landfills. Groundwater flow diverges from the Cheonan landfill while it converges to downgradient area in the Wonju landfill. Less permeable clayey silt layer or silty soil in the subsurface limited dispersion of leachate plume in the former landfill but highly permeable sandy soil with good lateral extent facilitated rapid plume dispersion in the latter landfill. In addition, hydraulic properties of the cover soil played a role in the different development of redox conditions, which resulted in significantly different concentrations of nitrates. Most problematic contaminants at downgradient wells of the landfills are ammonia and nitrate.

• Journal of Microbiology and Biotechnology
• /
• 제20권1호
• /
• pp.94-100
• /
• 2010

Zymomonas mobilis was immobilized in a modified graphite felt cathode with neutral red (NR-cathode) and Saccharomyces cerevisiae was cultivated on a platinum plate anode. An electrochemical redox reaction was induced by 3 volts of electric potential charged to the cathode and anode. The Z. mobilis produced 1.3-1.5 M of ethanol in the cathode compartment, whereas the S. cerevisiae produced 1.7-1.9 M in the anode compartment after 96 h. The ethanol produced by the Z. mobilis immobilized in the NR-cathode and S. cerevisiae cultivated on the platinum plate was 1.5-1.6 times higher than that produced under conventional conditions. The electrochemical oxidation potential inhibited Z. mobilis, but activated S. cerevisiae. The SDS-PAGE pattern of the total soluble proteins extracted from the Z. mobilis cultivated under the electrochemical oxidation conditions was gradually simplified in proportion to the potential intensity. Z. mobilis and S. cerevisiae were cultivated in the cathode and anode compartments, respectively, of an electrochemical redox combination system. The Z. mobilis culture cultivated in the cathode compartment for 24 h was continuously transferred to the S. cerevisiae culture in the anode compartment at a rate of 300 ml/day. Approx. 1.0-1.2 M of ethanol was produced by the Z. mobilis in the cathode compartment within 24 h, and an additional 0.8-0.9 M produced by the S. cerevisiae in the anode compartment within another 24 h. Thus, a total of 2.0-2.1 M of ethanol was produced by the electrochemical redox combination of Z. mobilis and S. cerevisiae within 48 h.

• 한국염색가공학회지
• /
• 제8권1호
• /
• pp.15-25
• /
• 1996

Wool fabric and merino wool top were dyed with two dyes, C.I. Acid Red 13 and C.I. Direct Blue 1 in presence of hydrogen peroxide/glyoxal redox system at various conditions such as dyeing time, temperature and redox concentration. The pH of dye bath was 4.5 in buffer solution of $KH_{2}PO_{4}$ (0.1mol/1)/$Na_{2}HPO_{4}$ (0.1mol/1). Also dyeing of cotton fabric was carried out with C.I. Direct Blue 1 in absence or presence of redox system. The color depth(K/S) increased with redox concentration and dyeing temperature. The increases in dyeing rate and equilibrium dye exhaustion of Acid Acid 13 and Direct Blue 1 on wool fiber and fabric in the present of hydrogen peroxide/glyoxal have been caused by decreasing in pH value during dyeing process which due to the decomposition of hydrogen ion in glyoxal with the assistance of hydrogen peroxide. But the decreases in exhaustion of Direct Blue 1 on cotton may be attributed to repulsive interac ion between salt and salt.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2002년도 추계학술발표회
• /
• pp.161-166
• /
• 2002

Bioremediation of trace metals in groundwater may require the manipulation of redox conditions via the injection of a carbon source. To simulate the numerous biogeochemical processes that will occur during the bioremediation of trace-metal-contaminated aquifers, a reactive transport model has been developed. The model consists of a set of coupled mass balance equations, accounting for advection, hydrodynamic dispersion, and a kinetic formulation of the biological or chemical transformations affecting an organic substrate, electron acceptors, corresponding reduced species, and trace metal contaminants of interest, uranium in this study. The redox conditions of the domain are characterized by estimating the pE, based on the concentrations of the dominant terminal electron acceptor and its corresponding reduced specie. This pE and the concentrations of relevant species we then used by a modified version of MINTEQA2, which calculates the speciation/sorption and precipitation/dissolution of the species of interest under equilibrium conditions. Kinetics of precipitation/dissolution processes are described as being proportional to the difference between the actual and calculated equilibrium concentration.

• Biomolecules & Therapeutics
• /
• 제26권1호
• /
• pp.19-28
• /
• 2018

Rapidly proliferating cancer cells require energy and cellular building blocks for their growth and ability to maintain redox balance. Many studies have focused on understanding how cancer cells adapt their nutrient metabolism to meet the high demand of anabolism required for proliferation and maintaining redox balance. Glutamine, the most abundant amino acid in plasma, is a well-known nutrient used by cancer cells to increase proliferation as well as survival under metabolic stress conditions. In this review, we provide an overview of the role of glutamine metabolism in cancer cell survival and growth and highlight the mechanisms by which glutamine metabolism affects cancer cell signaling. Furthermore, we summarize the potential therapeutic approaches of targeting glutamine metabolism for the treatment of numerous types of cancer.

• 한국환경보건학회지
• /
• 제23권4호
• /
• pp.97-103
• /
• 1997

Carbofuran was incubated for four weeks in three differenf types of paddy soil samples at 25$\circ$C. The soil samples prepared in the present study were as follows: control soil, 3% cellulose added soil and 10% cellulose added soil. The degradation rate of carbofuran significantly decreased by the addition of cellulose to soil(p<0.05). The initial pH of soils was 5.0. After incubation for four weeks, the pH of 10% cellulose added soil sample was lower than those of control soil and 3% cellulose added soil. According to increased organic carbon content of the soil, redox potentials of soils decreased. The decreased degradation rate of carbofuran in 10% cellulose added soil was related to the highly negative redox potentials in contrast with the oxidised conditions of control soil and 3% cellulose added soil.

• BMB Reports
• /
• 제35권2호
• /
• pp.194-198
• /
• 2002

Eukaryotic replication protein A (RPA) is a single-stranded(ss) DNA binding protein with multiple functions in DNA replication, repair, and genetic recombination. The 70-kDa subunit of eukaryotic RPA contains a conserved four cysteine-type zinc-finger motif that has been implicated in the regulation of DNA replication and repair. Recently, we described a novel function for the zinc-finger motif in the regulation of human RPA's ssDNA binding activity through reduction-oxidation (redox). Here, we show that yeast RPA's ssDNA binding activity is regulated by redox potential through its RPA32 and/or RPA14 subunits. Yeast RPA requires a reducing agent, such as dithiothreitol (DTT), for its ssDNA binding activity. Also, under non-reducing conditions, its DNA binding activity decreases 20 fold. In contrast, the RPA 70 subunit does not require DTT for its DNA binding activity and is not affected by the redox condition. These results suggest that all three subunits are required for the regulation of RPA's DNA binding activity through redox potential.

• Bulletin of the Korean Chemical Society
• /
• 제35권9호
• /
• pp.2803-2808
• /
• 2014

High potential and fast electron transfer of a cathode mediator are significant factors for improving the performance of biofuel cells. This paper reports the first synthesis of a cathode redox polymer that is a coordination complex of poly (acrylic acid-vinylpyridine-acryl amide) (PAA-PVP-PAA) and [Os(4,4'-dicarboxylic acid-2,2'-bipyridine)$_2Cl_2]^{/+}$ ($E^{\circ}=0.48V$ versus Ag/AgCl). Bilirubin oxidase can be easily incorporated into this polymer matrix, which carried out the four-electron oxygen under typical physiological conditions (pH 7.2, 0.14 M NaCl, and $37^{\circ}C$). This new polymer showed an approximately 0.1 V higher redox potential than existing cathode mediators such as PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$. In addition, we suggest increasing the polymer solubility with two hydrophilic groups present in the polymer skeleton to further improve fast electron transfer within the active sites of the enzyme. The maximum power density achieved was 60% higher than that of PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$. Furthermore, high current density and electrode stability were confirmed for this osmium polymer, which makes it a promising candidate for high-efficiency biofuel cells.

• Mycobiology
• /
• 제47권2호
• /
• pp.217-229
• /
• 2019

Two manganese peroxidases (MnPs), MnP1 and MnP2, and a laccase, Lac1, were purified from Trametes polyzona KU-RNW027. Both MnPs showed high stability in organic solvents which triggered their activities. Metal ions activated both MnPs at certain concentrations. The two MnPs and Lac1, played important roles in dye degradation and pharmaceutical products deactivation in a redox mediator-free system. They completely degraded Remazol brilliant blue (25 mg/L) in 10-30 min and showed high degradation activities to Remazol navy blue and Remazol brilliant yellow, while Lac1 could remove 75% of Remazol red. These three purified enzymes effectively deactivated tetracycline, doxycycline, amoxicillin, and ciprofloxacin. Optimal reaction conditions were $50^{\circ}C$ and pH 4.5. The two MnPs were activated by organic solvents and metal ions, indicating the efficacy of using T. polyzona KU-RNW027 for bioremediation of aromatic compounds in environments polluted with organic solvents and metal ions with no need for redox mediator supplements.

• 대한기계학회논문집B
• /
• 제40권12호
• /
• pp.777-784
• /
• 2016

바나듐 전해질 산화-환원 흐름전지(vanadium redox flow batteries, VRFBs)는 간헐적 에너지 저장 시스템의 에너지 저장장치로 사용된다. VRFBs는 재료 및 동작조건에 따라 성능의 차이를 보이며, 각 성능특성에 따른 VRFBs개발이 요구된다. 본 연구에 사용된 단위셀은 반응면적 $25cm^2$이며, 전해액은 0.6의 충전상태를 나타낸다. 방전전류밀도를 0에서 $520mA/cm^2$ 까지 변화시키면서 동시에 전해질 유량도 5mL/min에서 60mL/min까지 변화시켰다. 동일한 입구 전해액 상태에 따른 방전 성능 평가를 위해 4개의 탱크를 사용한 비순환 시스템을 구축하였다. 본 논문은 유량 및 전류밀도의 변화에 대한 단자전압을 측정하였으며, $25cm^2$ 반응면적을 가지는 바나듐계 산화-환원 유동전지 시스템의 최대전류밀도에 대한 실험식을 도출하였다.