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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 269 (1991), S. 1039-1044 
    ISSN: 1435-1536
    Keywords: Dielectric analysis ; single-shell model ; permittivity ; dielectric mixture equation ; erythrocyte ghost
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The purpose of this study is to confirm the applicability of dielectric mixture equations in dielectric analysis of biological cell suspensions. Two dielectric mixture equations, the Pauly-Schwan (P-S) equation and the Hanai-Asami-Koizumi (H-A-K) equation were tested using sheep erythrocyte ghosts whose internal solution is identical with the external solution. Dielectric measurements were carried out for the ghost suspensions over a frequency range 10 kHz to 100 MHz; a single dielectric relaxation was found between 100 kHz and 10 MHz. From the dielectric relaxation, the conductivity and permittivity of the ghost interior and the capacitance of the cell membrane were calculated following the P-S and H-A-K equations. When the H-A-K equation was employed (and as expected from the property of the ghosts), the estimated internal conductivity was in good agreement with the external conductivity at volume fractions up to about 0.7. With the P-S equation, on the other hand, the same results as above were obtained but only at low volume fractions below about 0.3. In addition, the H-A-K equation provided a better simulation for the observed relaxation curves than did the P-S equation, especially at high volume fractions. It is, therefore, concluded that the H-A-K equation is applicable to a wider range of volume fraction than is the P-S equation.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We report a change in the proliferative activity of mouse colonic epithelium due to development and aging. In order to measure the proliferative activity, colonic epithelium was immunostained for cyclin proliferating cell nuclear antigen (PCNA/cyclin), which appears from the Gl to the S phase of the cell cycle, and compared with labeling obtained by [3H]-thymidine radioautography. Litter mice of six age groups from the fetal period (embryonic day 19), newborn period (postnatal day 1), suckling period (postnatal day 5), weaning period (postnatal dy 21), adult period (2 month old) to the senescent period (11 month old) were examined by immunohistochemistry. The descending colons were fixed in methacarn (method-Carnoy) and embedded in paraffin. Sections were stained for PCNA/cyclin activity using 19A2 monoclonal antibody and the avidin-biotin peroxidase complex (ABC) technique. For radioautography, litter mice of nine age groups using in vivo intraperitoneal administration of [3H]-thymidine. The labeling indices of colonic epithelial cells in the proliferative zone were then analyzed and compared between the two investigative methods. Our results show that the prliferative activity of mice colon was high in the fetal and newborn periods and almost constant from the suckling period to senescence, as demonstrated by both PCNA/cyclin immunohistochemistry and [3H]-thymidine radioautography. The labeling index seen by PCNA/cyclin immunohistochemistry was, however, higher than that seen by [3H]-thymidine radioautography.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 268 (1990), S. 1059-1065 
    ISSN: 1435-1536
    Keywords: Dielectricproperty ; distribution ; microcapsule ; suspension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Theoretical consideration is made concerning the dielectric behavior of aqueous suspensions of W/O-type microcapsules containing aqueous electrolyte solutions, especially concerning distribution effects of the electrolyte release rate on the dielectric behavior. It is shown at first that the distribution of the release rate causes electrical conductivity of the capsule interior. Next, it is deduced, in the light of a theory of the interfacial polarization, that the distribution characteristics of the capsule interior's electrical conductivity are closely related to those of the relaxation time for a dielectric relaxation exhibited by the suspensions. Several formulas are derived to describe the relation between the distribution characteristics of the release rate and those of the relaxation time.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1435-1536
    Keywords: Dielectricrelaxation ; distribution ; microcapsule ; permeability ; porassiumchloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Release of KCl from a batch of PMMA microcapsules containing an aqueous 3 mM KCl solution was studied with the following two methods: 1) dielectric measurements of suspensions of the microcapsules in distilled water. The electrical conductivity of capsule interior was estimated with this method. 2) Measurements of the conductivity of suspending medium of the microcapsule suspensions. These two kinds of experiments provided us with information about the amount of KCl remaining in the capsules and that diffused outside. Results of these experiments showed that the microcapsules varied in their release rate of KCl. A distribution function of the release rates was derived from the results of the dielectric measurements. That distribution function was successful in explaining the results of the measurements of the conductivity of suspending medium. Furrther examination revealed that the release rate increased with the increase in the thickness of capsule wall.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1435-1536
    Keywords: Bias-voltage effect ; concentration polarization ; dielectric relaxation ; electrodialysis ; ion-exchange membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract As the application of a dielectric theory proposed previously (J Membrane Sci 64:153–161 (1991)), theoretical formulation and the practical procedure of dielectric analysis are developed to calculate the structural parameters such as the conductivity gradient and the thickness of the concentration polarization layer, the capacitances and the conductances of the two adjoining aqueous phases from the observed dielectric parameters. The procedure of calculation consequent upon the theoretical formulation was applied to double relaxation data observed for cation-exchange membrane systems under application of d.c. bias voltage. As a consequence, the structural parameters of concentration polarization were readily obtained with accuracy.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 270 (1992), S. 78-84 
    ISSN: 1435-1536
    Keywords: Dielectric relxation ; biological cell ; sedimentation ; erythrocyte ; interfacial polarization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A dielectric theory was developed to analyze dielectric relaxation of a system in which biological cells are settling perpendicular and parallel to electrode planes. The theory predicts that the dielectric relaxation intensity (Δε) increases markedly with increasing time when the settling direction is perpendicular to electrode planes, whereas Δε is less sensitive to the sedimentation in a direction parallel to electrode planes. These theoretical expectations agreed well with the experimental results obtained with sheep erythrocytes. Analysis based on this theory provided the sedimentation rate of sheep erythrocytes, the results being in agreement with those obtained by the conventional method.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract YIG films, substituted with Bi, Ti, Ga and La, were grown on a (111) plane of Gd3Ga5O12 or (Gd, Ca)3(Ga, Mg, Zr)5O12 by a liquid phase epitaxial method. With the increase of the concentration of Bi atoms, which are substituted at 24c sites of YIG, the magnetic hyperfine fields at 16a and 24d Fe sites increased and the direction of magnetic moments changed from parallel to 45° to the (111) plane. With the increase of Ga concentration, the hyperfine fields at 16a and 24d Fe sites decreased. The hyperfine interaction and the substitution effect of YIG films are discussed.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 573-574 
    ISSN: 0935-6304
    Keywords: Electrochromatography ; Multi-channel column ; Sample loading capacity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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