FLUCTUATION STUDIES OF ELECTROLYTE SOLUTIONS AND LIPOSOME SUSPENSIONS.
Item
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Title
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FLUCTUATION STUDIES OF ELECTROLYTE SOLUTIONS AND LIPOSOME SUSPENSIONS.
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Identifier
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AAI8023679
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identifier
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8023679
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Creator
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STRASSFELD, MOSES J.
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Contributor
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Michael E. Green
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Date
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1980
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Physical
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Abstract
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A method for determining relaxation times associated with ion transport through liposome membranes, using ion concentration fluctuation spectroscopy (adapting a technique of Feher and Weissman (Proc. Natl. Acad. Sci. (USA), 1973,70,870)), is presented. To be measurable, fluctuations in a very small volume are required; this is achieved by use of a 250 (mu)m thick ruby with an approximately 10 (mu)m diameter minimum aperture. The method is now suitable for the determination of relaxation times in the 10 ms to 10 (mu)s range, and this range can be extended.;The method has been applied to a gramicidin-D doped by soy-lecithin in 0.149 M KCl vesicle preparation. Two relaxation phenomena have been observed. The first, a -2 slope in the region 20 to 150 Hz, is attributed to the high frequency portion of the known gramicidin relaxation. The second, at 152 (+OR-) 46 Hz (one standard deviation), is shown to be characteristic of the vesicles themselves.;Additionally, noise spectra of potassium chloride solutions with concentrations 0.005 M and 0.149 M were measured, as were spectra of sodium chloride with concentrations 9.9(.)10('-4) M to 0.149 M. At NaCl concentrations of 6(.)10('-3) M and above, and for 0.149 M KCl, the spectrum is 1/f in the measured range, 30 Hz to 10 kHz, when the current is 5 (mu)a or 7 (mu)a; it is usually steeper at 12 (mu)a. For four concentrations showing 1/f noise the ratio of spectral intensities for the 7 (mu)a to the 5 (mu)a spectra is 2.14 (+OR-) 0.33 (one standard deviation), in agreement with the expectation of proportionality to I('2).;The flow rate through the ruby aperture was measured by applying a hydrostatic pressure and determining the resulting current. The Onsager Reciprocal relations were used to determine the mass flow accompanying the electrical current. The mass flow was calculated to be 0.01 ms('-1) on average; and 0.5 ms('-1) at the 10 (mu)m minimum diameter opening.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Chemistry
