• 한국방사선학회논문지
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• 제7권1호
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• pp.85-91
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• 2013

감마선이 조사된 세포막 모델에서 $K^+$ 와 $Na^+$의 선택적 전달특성을 연구하였다. 이 실험에 사용된 세포막 모델은 $Na^+$ 슬폰화 폴리스티렌-디비닐벤젠(polystyrene-divinylbenzene) 혼성 중합막을 사용하였다. 이온의 초기플럭스는 $H^+$ 이온 농도의 증가와 함께 증가하였다. 이 실험의 조건을 pH 0.5-3, 온도 $15-65^{\circ}C$로 하여 첫 번째 조사되지 않은 막의 $K^+$와 $K^+/Na^+$의 선택도는 약 1.06 - 1.13이고 두 번째 조사된 막의 $K^+$와 $K^+/Na^+$의 선택도는 약 0에 가깝다. 조사된 막의 pH의 추진력은 조사되지 않은 막보다 약 4-5배 정도 유의성 있게 증가하였다. 세포막모델에서 $K^+$와 $Na^+$의 선택적 전달특성이 비정상적이기 때문에 세포장해가 세포에서 발현된다.

• KSBB Journal
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• 제13권3호
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• pp.268-271
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• 1998

Bacteriorhodopsin in the purple membrane (PM) of halobacteria has recently been attracting much attention to be used as a component of molecular electron device and optical computers. In order to increase the productivity of bacteriorhodopsin in high cell density cultures of Halobacterium halobium R1, an internal membrane cell-retention bioreactor system was employed. As a result, the production of cell mass at OD660 of 12 and of bacteriorhodopsin at 125-130 mg/L were obtained using the internal membrane bioreactor system at a dilution rate of 0.066 hr-1. The productivity achieved by the internal membrane system (0.7 mg/L$.$hr) was 3.5-fold higher than that obtained by the corresponding batch cultivations (0.2 mg/L$.$hr).

• 신재생에너지
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• 제3권1호
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• pp.68-74
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• 2007

The fuel cells for portable application are attracted using a liquid fuel such as methanol and chemical hydride solutions. Recently, DBFC [Direct Borohydride Fuel Cell] is a candidate for power of portable electronic devices. In this work, the anion exchange membrane and non-precious catalyst for the DBFC were concerned. Anion-exchange membrane was fabricated by amination of polysulfone followed chloromethylation. Non-precious catalysts such as raney-Ni and Ag were used as an anode and cathode catalyst. The optimum conditions of catalyst slurry mixing and MEA fabrication were developed. The single cell performance using anion exchange membrane and non-precious catalyst was evaluated and the results were compared with cation exchange membrane [Nafion membrane] and precious catalysts.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.143-150
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• 1996

The membrane fatty acid composition of tumor cell can be modified either in cell by altering the lipid composition of the medium of during growth in animals by changing the dietaty fat composition. These modifications are associated with changes in membrane physical properties and certain cellular functions, including carrier-mediated transport and enzyme contained within the membrane. Such effects influence the transport of nutrients and chemotherapeutic agents in cancer cells .Fatty acid modification also can enhance the sensitivity of the neoplastic cell to chemotherapy. The alteration in plasma membrane composition will be affected through dietary supplementations and the potential value to cancer patients could be a better understanding of the effects of diet on responsiveness of neoplasms to chemotherapy, i.e. cancer patients' chances for a "cure" can be improved by diet changes prior to treatment.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.98.2-98.2
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• 2011

For optimal performance of a proton exchange membrane fuel cell (PEMFC), the membrane electrode assembly (MEA) requires hydration, and the membrane's conductivity depends on water content. A humidifier is required to ensure that the reactant gas, usually hydrogen and air, is hydrated before entering the fuel cell. Dry membrane operation or improper hydration causes performance degradation. Typically, the humidification of a fuel cell is carried out by means of an internal or external humidifier. A membrane humidifier is applied to the external humidification of transportation or residential power generation fuel cell due to its convenience and high performance. In this study, The experiments were constructed with a plate-type membrane humidifier in terms of geometric parameters and operating parameters. The results show that the temperature and pressure, the channel length, the membrane thickness and gas flow rate are critical parameters affecting the performance of the humidifier.

• 비파괴검사학회지
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• 제32권3호
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• pp.263-268
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• 2012

It is important to know the mechanism of cell membrane fluctuation because it can be readout for the nanomechanical interaction between cytoskeleton and plasma membrane. Traditional techniques, however, have drawbacks such as probe contact with the cell surface, complicate analysis, and limit spatial and temporal resolution. In this study, we developed a new system for non-contact measurement of nano-scale localized-cell surface dynamics using modified-scanning ion-conductance microscopy. With 2 nm resolution, we determined that endothelial cells have local membrane fluctuations of ~20 nm, actin depolymerization causes increase in fluctuation amplitude, and ATP depletion abolishes all membrane fluctuations.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 추계 총회 및 학술발표회
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• pp.1-6
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• 1994

Many useful biomaterials like enzymes are contained in yeast cells. However, the release of these intracellular biomateriais from the cells is required to recover them with hot water, solvent or various cell breakage methods of mechanical or non mechanical ones. The cell lysis or breakage of yeast is usually made by solvent like ethyl acetate and mechanical disintrgration with high pressure homogenizer or agitating beads mill. The separation of cell debris (i.e. solid liquid separation) is done by centrifuge or membrane depending on the recovery conditions. The features of both separation methods are shown in Tables 1 and 2. As it is often difficult to obtain a clear supernatant by centrifuge from the suspension containing cell debris, the membrane separation is also often used to gel a clear supernatant. In this report we introduce the several applications of membrane separation to separate the cell debris of yeast disintegrated chemically or mechanically and to recover the intracellular biomaterials.

• 멤브레인
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• 제14권1호
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• pp.53-56
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• 2004

Direct Methanol Fuel Cell (DMFC) is considered as a candidate technology for applications in stationary, transportation as well as electronic power generation purposes. To develop a high performance direct methanol fuel cell(DMFC), a competent electrolyte membrane is needed. The electrolyte membrane should be durable and methanol crossover must be low. One of the approaches to increase the stability of generally used polymer electrolyte membranes such as Nafion against swelling or thermal degradation is to bond it with an inorganic material physically or chemically. In Noritake Company, we have developed a novel method of reinforcing the polymer electrolyte matrix with inorganic fibers. Methanol crossover values measured were significantly lower than the original polymer electrolyte membranes. These fiber reinforced electrolyte membranes (FREM) were used for DMFC study and stable power output values as high 160 mW/$\textrm{cm}^2$ were measured. The details of the characteristics of the membranes as well as I-V data of fuel cell stacks are detailed in the paper.

• 한국수소및신에너지학회논문집
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• 제29권6호
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• pp.620-626
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• 2018

Recently, fuel cell field is receiving much attention as an environmentally friendly energy in the world. Among the various types of fuel cells, in the case of PEMFC, ions move through the membrane in the middle of the unit cell. Therefore, proper moisture is required inside the PEMFC. In the case of membrane type humidifier, flat membrane or hollow fiber membrane is mainly used. Since various parameters can change the performance, the performance investigation has to be carried out with parameters. In this study, water transport of hollow fiber membrane was investigated in terms of principle operating conditions such as temperature and flow rate.

• Applied Microscopy
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• 제19권1호
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• pp.34-48
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• 1989

The oval shaped pericardial cells are clustered along the lateral sides of the heart and irregularly connected with the heart. The cells are bounded by a basement membrane. The basement membranes of the connected two peicardial cells are irregularly linked each other there-fore funnels are formed. The multiple invaginations of the cell membrane are observed and septate junctions develope at the part of enterance of the cell membrane. The coated pits are appeared in the inner side of the invaginated cell membrane. The coated vesicles, tubular and spherical shaped vesicle, Golgi complex containing high electron densed material in the cisternae and mitochondria are observed in the cytoplasm and lysosomes are remarkably well developed. The whirled membrane structures in the multiformed complex bounded by single membrane are linked with low electron densed granules and spherical shaped small granules having high electron density with $0.03{\mu}m$ in diameter are located between the whirled membrane in a row and gradually secretes the granules and then they produced the multilamellar body. The lysosomal regions of cytoplasm of pericardial cell are appeared negative reaction to the acid phosphatase and according to the results of the electrophoresis, lipoproteins having acid phosphatase activity are contained. The axon is contacted with the pericardial cells.