• Title/Summary/Keyword: Donnan equilibrium

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Performance of Annealed Polyacrylonitrile Nanofiltration Membrane (아닐링된 폴리아크릴로니트릴 나노막의 성능)

  • Lee Kew-Ho;Kim In-Chul
    • Membrane Journal
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    • v.15 no.1
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    • pp.15-21
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    • 2005
  • The integrally skinned asymmetric PAN ultrafiltration membranes were annealed for reducing the pore size. The effect of the chemical structure of two PAN polymers (homo- and copolymer) on annealing was investigated. The annealing of PAN polymer was strongly affected by the chemical structure of the polymer. In other words, the annealing effect of the copolymer was much larger than that of the homopolymer due to its less rigid structure of the main chain. Before annealing, the membranes were usually preheated in water in terms of the complete removal of remained solvents in the membranes. The annealing effect was bigger when no preheating. However, the preheating of the membrane before annealing at high temperatures leads to an increase in the pore size of membranes. The surface of the membranes was slightly negative and the salt rejection of PAN nanofiltration membrane was in the following order: R(Na₂SO₄) > R(NaCl) > R(MgSO₄) > R(CaCl₂). This salt rejection behavior could be explained by the Donnan equilibrium and the electroneutrality.

Bioelectric Phenomena (생체전기현상)

  • 이경중;윤형로
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.4
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    • pp.5-11
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    • 2004
  • 생체 시스템은 수많은 세포들로 구성되어 있다. 일반적으로 세포막은 단백질과 지방의 혼합체로 구성되어 있으며 두께는 7.5-10nm 정도이다. 단백질은 지방과 함께 세포막을 통한 물질의 이동을 제어하는 역할을 한다. 특히 지방층은 지방에 잘 용해되는 산소나 탄산가스 등은 잘 통과시키지만, 지방에 잘 용해되지 않는 나트륨, 칼륨, 칼슘, 글루코스, 아미노산 등은 지방층 내부에 삽입되어 있는 단백질에 의해 조절된다.(중략)

Interrelation of Yin and Yang in Action Potential of Cell Membrane (세포막 활동전압에서 음양(陰陽)의 상호관계)

  • Park, Sun Young;Kim, Ho Hyun
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.27 no.5
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    • pp.563-569
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    • 2013
  • This study was undertaken to apply the yin-yang theory in action potential. In order to apply the yin-yang theory in action potential, nature of yin and yang, interrelation of yin and yang and action potential in cell were reviewed. According to the yin-yang theory, inner cellular space corresponds to yin, but outer cellular space corresponds to yang. If we classify ions in intracellular fluid or extracellular fluid by nature of yin and yang, potassium(K+) corresponds to yang within yin(陰中之陽), protein(Pr-) corresponds to yin within yin(陰中之陰) in intracellular fluid, and sodium(Na+) corresponds to yang within yang(陽中之陽), chloride(Cl-) corresponds to yin within yang(陽中之陰) in extracellular fluid. Double donnan equilibrium and equilibrium potential were caused by intracellular anion(Pr-) and extracellular cation(Na+) are related with mutual rooting of yin and yang(陰陽互根) and opposition of yin and yang(陰陽對立). The influx and efflux of ion through cell membrane means waxing and waning of yin and yang(陰陽消長), the change of membrane potential means yin-yang conversion(陰陽轉化) during action potential.

Evaluation of the Effective Charge Density on Low Pressure Nanofiltration with the Separation Characteristics of Monovalent and Divalent Solutes in the Production of Drinking Water

  • Oh, Jeong-Ik;Taro, Urase
    • Environmental Engineering Research
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    • v.16 no.1
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    • pp.29-34
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    • 2011
  • The electric charge on a membrane was investigated by analyzing the experimental rejection of various monovalent and divalent ionic solutes. The characteristics of the separation of ionic solutes using various nanofiltration membranes were obtained from an experimental nanofiltration set-up, with a surface area of $40cm^2$ under the operational pressures between 0.25-0.3 MPa. The state of the membrane electric charge was observed using separation coefficients, i.e., the permeation ratio of monovalent to divalent ions. To confirm the state of the membrane charge observed via the separation coefficient, a calculation using the extended Nernst-Planck equation, coupled with the Donnan equilibrium, assuming different electric charge states of the membrane, was compared with the experimental rejection of ionic solutes. The examination of the characteristics of separation using three types of nanofiltration membranes showed that one of the membranes carried a negative/positive double charge density inside, while other two membranes carried either a positive or negative charge density.

Modeling the electric transport of HCl and H3PO4 mixture through anion-exchange membranes

  • Koter, Stanislaw;Kultys, Monika;Gilewicz-Lukasik, Barbara
    • Membrane and Water Treatment
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    • v.2 no.3
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    • pp.187-205
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    • 2011
  • The electric transport of the mixture of hydrochloric and phosphoric acids through strong base (Neosepta ACM) and weak base (Selemion AAV) anion-exchange membranes was investigated. The instantaneous efficiency of HCl removal from the cathode solution, $CE_{Cl}$, with and without $H_3PO_4$ was determined. It was found that $CE_{Cl}$ was 0.8-0.9 if the number of moles of elementary charge passed through the system, $n_F$, did not exceed ca. 80% of the initial number of HCl moles in the cathode solution, $n_{Cl,ca,0}$. The retention efficiency of $H_3PO_4$ in that range was close to one. The transport of acid mixtures was satisfactorily described by a model based on the extended Nernst-Planck and Donnan equations for $n_F$ not exceeding $n_{Cl,ca,0}$. Among the tested model parameters, most important were: concentration of fixed charges, the porosity-tortuosity coefficient, and the partition coefficient of an undissociated form of $H_3PO_4$. For the both membranes, the obtained optimal values of fixed charge concentration, $\bar{c}_m$, were up to 40% lower than the literature values of $\bar{c}_m$ obtained from the equilibrium measurements. Regarding the $H_3PO_4$ equilibria, it was sufficient to consider $H_3PO_4$ as a monoprotic acid.

Changes of LDH Subunit Combinations Induced by Tetrodotoxin (Tetrodotoxin에 의하여 유발되는 LDH 하부단위체 조합의 변화)

  • Kim, Sang-Yeop;Yum, Jung-Joo
    • The Korean Journal of Zoology
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    • v.28 no.4
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    • pp.227-236
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    • 1985
  • In an attempt to make a scrutiny into a mechanism for the formation of quaternary structure of LDH isozymes, male mice were intraperitoneally exposed to a wide range of tetrodotoxin concentration and the changes in relative percentage of the five isozymes were monitored by electrophoresis and subsequent densitometry. The observations that a conspicuous increase of the $H_4$ isozyme was demonstrated in nearly all brain tissues, that the $M_4$ isozyme of skeletal muscle tissue was slightly increased while the $M_3H$ and $M_2H_2$ isozymes were decreased, that the M/H ratio was strikingly reduced in heart tissue and that assembly of $H_4$ isozyme was revealed in liver tissue although its rate was extremely low suggest that new intracellular ionic environment established by compulsory change in Donnan equilibrium could alter the LDH isozyme distribution. The reduction of assembly of $M_3H$ isozyme found in mouse tissues exposed to tetrodotoxin also seems to suggest that the subunit combination of 3M+H is very unfavorable in an intracellular environment deviated from its accustomed one. It was reaffirmed that there might occur TTX-insensitive sodium channels in plasma membrane.

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Changes in Water and Electrolyte Distribution and Blood Glucose Concentration following Irreversible Hemorrhagic Shock (비가역성 실혈성 쇽에서 본 가토심근, 혈장의 전해질 및 혈당량 변화)

  • Kim, Ki-Whan;Nam, Kee-Yong
    • The Korean Journal of Physiology
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    • v.2 no.1
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    • pp.47-52
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    • 1968
  • Twenty white rabbits anesthetized with nembutal (30 mg/kg) were employed in this experiment. Five of them served as controls; the remaining rabbits as experimental group were subjected to irreversible hemorrhagic shock. Shock was induced by bleeding the animals until mean blood pressure decreased to a level of 50-40 mmHg. This level of pressure was maintained for 3-4 hours, after which the drawn blood was reinfused. The reinfusion of blood caused the elevation of arterial pressure almost the control level for some minutes, after which a gradual and progressive decline of blood pressure became evident. This decline was thought to be the result from irreversible hemorrhagic shock. When mean blood pressure declined to less than 50 mmHg, chest was opened and samples of arterial blood and left ventricular muscle were taken. Left ventricular muscle and blood plasma were analyzed for potassium, sodium, chloride and water content. Blood glucose concentration was determined by Somogyi-Nelson's method. Extracellular and intracellular myocardial water and electrolyte content were calculated on the basis that electrolytes are distributed between plasma water and interstitial water according to Gibbs-Donnan equilibrium. In this calculation extracellular water was substituted for Na space. The findings obtained were as follows: 1. The concentration of blood glucose was 87mg% in the controls and it rose to 222 mg% in shock (P<0.01). 2. Plasma potassium elevated significantly from 3.3 mEq/l in controls to 8.0 mEq/l in shock (P<0.01), while small decreases in sodium (151-146 mEq/l) and chloride (102-96 mEq/l) were observed (P<0.3, P<0.1), 3. The changes of blood water content (83.1-84.3%) and cardiac water content (77.5-78.3 gm/100gm WT) were observed. 4. In control animals myocardial potassium levels which averaged 30.2 mEq/100 gmDT rose significantly to 40.3 mEq/100 gmDT in shock (P<0.01), while moderate decreases in sodium(16.3-14.3 mEq/100 gmDT) were observed in shock. 5. The calculated transmembrane resting potential of left ventricular muscle of control animals averaged 95 mV, while rabbits in shock averaged 77 mV. (P <0.01). The findings of this experiment do not correspond with the conclusions that myocardial depression seems to be the cause of irreversible hemorrhagic shock, because the excitability of heart muscle is elevated. From the point of view that the lowered transmembrane resting potential, the cause of death in terminal stage of irreversible hemorrhagic shock may be ventricular fibrillation. It can't be said, however, that the lowered transmembrane resting potential is responsible for the transition from reversible to irreversible hemorrhagic shock. The marked increase in blood glucose suggested that glycogenolysis in the liver is favorably active in shock.

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