• Title/Summary/Keyword: Cell membrane

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Adsorption of $\textrm{Pb}_{2+}$ in the components of bacterial cell membrane

  • Kim, Mal-Nam
    • Journal of Microbiology
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    • v.33 no.4
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    • pp.278-282
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    • 1995
  • S. epidermidis cell was fractionated into cell wall, cell membrane and cytoplasm. The cell membrane adsorbed the most abundant $\textrm{Pb}_{2+}$ per unit dry weight of the three fractions tested. Adsorption behavior of $\textrm{Pb}_{2+}$ in lipid and protein, which are the main components of the cell membrane, indicated that phosphatidylethanolamine and phosphatidylinositol having phosphoryl group and gangliosides containing carboxyl groups adsorbed much more $\textrm{Pb}_{2+}$ than triglycerides lacking any chargeable functional groups. Protein purified from cell membrane adsorbed larger amount of $\textrm{Pb}_{2+}$ than total native cell membrane or cell membrane lipid.

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Performance Evaluation of Platinum Dispersed Self-humidifying Polymer Electrolyte Membrane Prepared by Using RF Magnetron Sputter

  • Kwak, Sang-Hee;Yang, Tae-Hyun;Kim, Chang-Soo;Yoon, Ki-Hyun
    • Journal of the Korean Ceramic Society
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    • v.40 no.2
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    • pp.118-122
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    • 2003
  • The performance evaluation on Pt loading in the self-humidifying polymer electrolyte membrane for Polymer Electrolyte Mem-Brane Fuel Cell(PEMFC) was investigated by using single cell test and measurement of membrane resistance. The self-humidifying membrane comprised two membranes made of perfluorosulfonylfluroride copolymer resin and fine Pt particles tying between them, coated by sputtering. From the results of performance characteristics of self-humidifying membrane cell with different Pt loading, a single cell using self-humidifying membrane with 0.15 mg/$\textrm{cm}^2$ Pt loading showed better performance than that with the others over entire current density. Also, a single cell with 0.15 mg/$\textrm{cm}^2$ Pt loading had a lower resistance value than the other cells under externally nonhumidifying condition. It is indicated that the water produced in the membrane cell with 0.15 mg/$\textrm{cm}^2$ Pt loading showed a higher provision to maintain ionic conductivity of the membrane than the other cells. The optimum amount of Pt particles embedded in the membrane for self-humidifying PEMFC was determined to be about 0.15 mg/$\textrm{cm}^2$.

Binding sites for lead ion in staphylococcus epidermidis

  • Kim, Mal-Nam;Sung, Hye-Yoon
    • Journal of Microbiology
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    • v.33 no.3
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    • pp.228-233
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    • 1995
  • As S. epidermidis cell was fractionated into cell wall, cell membrane, and cytoplasm, the cell membrane proved to be the most efficient absorbent for lead ion. Utrasonication was effective, when the cells were treated during their exponential growth. The amount of the lead ion adsorbed in cell membrane decreased as hydrogen ion concentration of solution increased. Protein purified from the cell membrane showed higher adsorption capacity for the lead ion than peptidoglycan, teichoic acid from cell wall, or cell membrane lipid. Modification of carboxyl groups in the membrane protein with ethylenediamine and 1-ethyl-3-carbodiimide hydrochloride resulted in a considerable decrease of lead ion adsorption capability, suggesting that the main binding site for lead ion was the carboxyl groups of protein in cell membrane.

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Solanum Nigrum Polysaccharide (SNL) Extract Effects in Transplanted Tumor-bearing Mice - Erythrocyte Membrane Fluidity and Blocking of Functions

  • Yuan, Hong-Liang;Liu, Xiao-Lei;Liu, Ying-Jie
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.23
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    • pp.10469-10473
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    • 2015
  • Background: Solanum nigrum L. has been used in traditional Chinese medicine because of its diuretic and antipyretic effects. The present research concerned effects of crude polysaccharides isolated from Solanum nigrum L. on erythrocyte membranes of tumor-bearing $S_{180}$ and $H_{22}$ in mice. Materials and Methods: Fluorescence-labeled red blood cell membranes were used with DPH fluorescence spectrophotometry to examine erythrocyte membrane fluidity, and colorimetry to determine degree of erythrocyte surface membrane blocking. Extent of reaction by tumor-bearing mice with the enzyme erythrocyte membrane bubble shadow detection of red cell membrane variation in the degree of closure before and after administration. Results: Solanum nigrum polysaccharide could significantly improve the $S_{180}$ and $H_{22}$ tumor-bearing mice erythrocyte membrane fluidity, compared with the control group, the difference was significant (p<0.01), SNL can significantly improve the red blood cell membrane and then $S_{180}$ tumor-bearing mice sealing ability, compared with the negative control group, the difference was significant(p<0.05, p<0.01). $H_{22}$ tumor-bearing mice can increase red cell membrane and then sealing ability, the difference was significant (p<0.05). Solanum nigrum polysaccharide degree of fluidity and blocking two transplanted tumors in mice restored the ability to raise the red cell membrane has a significant effect. Conclusions: Solanum nigrum L.-type mice transplanted tumor can affect the red blood cell membrane fluidity and re-closed, through the red cell membrane of red blood cells to enhance the immune function of the possibility of erythrocyte immunity against tumor formation garland provide experimental basis.

Current Patents and Papers Research Trend of Fuel Cell Membrane (특허 및 논문 게재 분석을 통한 연료전지용 전해질막의 연구동향)

  • Woo, Chang Hwa
    • Membrane Journal
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    • v.26 no.6
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    • pp.407-420
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    • 2016
  • The fuel cell technology as a green energy source has been actively studied to solve energy shortages and pollution problems. The generating efficiency of fuel cell is high because the electricity is directly produced by using hydrogen and oxygen and the additional power generator is not needed. The key technology is the manufacturing process of polymer electrolyte membranes for polymer electrolyte membrane fuel cell (PEMFC) system. The Nafion, perfluoro-based polymeric membrane is mainly used as a polymer electrolyte membrane. However, the Nafion is expensive and rapidly decreases the performance of Nafion at high temperature. So, many researchers are lively studying new alternative electrolyte membranes. In this review, through the technology competitiveness evaluation of patents and papers, the frequencies of presentation are filed by country, institution and company. In addition, polymer electrolyte membrane fuel cell, direct methanol fuel cell and alkaline fuel cell are also filed.

Reduction of Methanol Crossover in a Direct Methanol Fuel Cell by Using the Pt-Coated Electrolyte Membrane

  • Jung, Eun-Mi;Rhee, Young-Woo;Peck, Dong-Hyun;Lee, Byoung-Rok;Kim, Sang-Kyung;Jung, Doo-Hwan
    • Journal of the Korean Electrochemical Society
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    • v.11 no.1
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    • pp.1-5
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    • 2008
  • A Pt-layer was deposited on the anode side of a Nafion membrane via a sputtering method in order to reduce methanol crossover in a direct methanol fuel cell (DMFC). The methanol permeation and the proton conductivity through the modified membranes were investigated. The performances of the direct methanol fuel cell were also tested using single cells with a Nafion membrane and the modified membranes. The Pt-layers on the membrane blocked both methanol crossover and proton transport through the membranes. Methanol permeability and proton conductivity decreased with an increase of the platinum layer thickness. At methanol concentration of 2 M, the DMFC employing the modified membrane with a platinum layer of 66 nm-thickness showed similar performance to that of a DMFC with a bare Nafion membrane in spite of the lower proton conductivity of the former. The maximum power density of the cell using the modified membrane with a platinum layer of 66 nm-thickness increased slightly while that of the cell with the bare membrane decreased abruptly when a methanol solution of 6M was supplied.

The Effect of Ion Exchange Membrane on the Electrical Conduction in Metal Fuel Cell (금속연료전지에서 이온교환막이 전기전도에 미치는 영향)

  • Kim, Yong-Hyuk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.12
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    • pp.2235-2239
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    • 2010
  • In this study, The cation exchange membrane and the anion exchange membrane affect in electrical conduction of metal fuel cell was investigated. Magnesium material as anode electrode and the NaCl solution dissolved with 5~15wt% as electrolyte were used for the metal fuel cell. It was found that magnesium slag where flows toward the air electrode was suppressed by using ion exchange membrane. The open circuit voltage variation during discharge has very flat pattern by using ion exchange membrane, but the case which is not the exchange membrane, the open circuit voltage increased according to time. When using the anion exchange membrane, the electric current was higher case of the cation exchange membrane, as a result of higher equivalent conductivity in anion Cl-. The cation exchange membrane was observed with the fact that the output power is excellent in compared with anion exchange membrane.