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  • Polymer and Materials Science  (6)
  • Skin impedance  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Medical & biological engineering & computing 19 (1981), S. 302-310 
    ISSN: 1741-0444
    Keywords: Electrical properties of skin ; Skin impedance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract This paper describes the non-linear electrical properties of the skin during the passage of a sinusoidal current from the standpoint of the constant-current method. The non-linearity occurs in the current dependency of the skin impedance and in Lissajous figures. It exhibits both rapid and slow variations. The concept of a non-linear impedance and its equivalent circuit are introduced for a sinusoidal voltage. With regard to the current dependency of the impedance it can be said that both the starting point and the degree of the dependency vary with frequency and impedance. The nonlinearity is more apparent with a larger current, a lower frequency, and a higher impedance. with an increasing current, the ionic conductance increases and the polarisation admittance decreases. Lissajous figures are formed when the voltage is distorted notably from the sinusoidal wave form. Detailed investigations are undertaken for the elliptic figures, third harmonics, rectification, and breakdown of the skin appearing with a decrease of the frequency and increase of the current. Finally, the special mechanism of the ionic conduction in the keratin layer is indicated as one of the causes for non-linearity.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Medical & biological engineering & computing 17 (1979), S. 135-137 
    ISSN: 1741-0444
    Keywords: Impedance measurement ; Skin impedance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 3671-3679 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The novel reactive antioxidants based on tetrazoles that are stable at room temperature and convertible into the highly reactive nitrileimines by pyrolysis were prepared and the reactivity for carbon-carbon double bonds was evaluated. Antioxidants, i.e., 2-substituted phenyl-5-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)tetrazoles (PHPT) were prepared with the reaction of p-toluenesulfonylhydrazone of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and substituted phenyl diazonium chloride in a mixed solvent of pyridine, ethanol, and water at -10°C to -20°C in 31-61% yields. To evaluate the reactivities of PHPT for carbon-carbon double bonds, m-chloro-substituted PHPT was pyrolyzed in an excess of styrene at 160-170°C for 0.5 h to give the 1-(3′-chlorophenyl)-3-(3″,5″-di-tert-butyl-4″-hydroxyphenyl)-5-phenyl-2-pyridazoline in a 44.1% yield by 1,3-dipolar addition reaction of the nitrileimine formed from the m-chloro-substituted PHPT. The thermogravimetric analysis of a mixture of proton isomer of PHPT and liquid polybutadiene showed that PHPT attached to liquid polybutadiene with an accompanying evolution of nitrogen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 89-98 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The chemical reactivities of novel reactive antioxidants based on tetrazoles for carbon-carbon double bonds of liquid polybutadiene and their antioxidation activities toward isoprene rubber were evaluated. These antioxidants, i.e., 2-substituted phenyl-5-(3′,5′ -di-tert-butyl-4′-hydroxyphenyl)tetrazoles (PHPT), were pyrolyzed in liquid polybutadiene at 160-170°C for 30 min to attach to rubber in extents of 61-85% of the nitrileimines formed from PHPT by 1,3-dipolar addition reaction. The reactivities of PHPT followed the order p-Cl 〉 m-Cl 〉 H 〉 p-CH3 〉 m-CH3, p-OC2H5, suggesting that PHPT reacts with diene rubber in electrophilic reaction and p-derivatives exhibit higher contents of binding than m-derivatives due to steric hindrance. From oxygen absorption data, the antioxidation activities of PHPT for isoprene rubber vulcanizates followed the order m-Cl, m-CH3 〉 H, p-Cl, p-Cl, p-CH3 〉 p-OC2H5. Isoprene rubber vulcanizates, obtained after pretreatment with PHPT by heating, were extracted with acetone, followed by aging to show that there was good retention and appreciable antioxidation activities of PHPT, especially, p-CH3 and p-Cl substituted PHPT.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 4201-4201 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 1197-1202 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monodisperse microspheres of poly(diethylene glycol dimethacrylate) with diameters in the size range 0.4-4.8 μm were prepared by the radiation-induced polymerization. Effects of solvent viscosity and monomer solubility were investigated for various kinds of solvents. The number of the nuclei, produced in the early stage of the polymerization, was found to be constant during the remainder of the polymerization. The nuclei grow to be monodisperse polymer particles without aggregation. This is attributed to the low mobility of the growing polymer particles.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Medical & biological engineering & computing 30 (1992), S. 562-564 
    ISSN: 1741-0444
    Keywords: Control instrument for drowsines ; Galvanic skin reflex ; Skin impedance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Medical & biological engineering & computing 16 (1978), S. 592-594 
    ISSN: 1741-0444
    Keywords: Dispersion of skin impedance ; Skin impedance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Medical & biological engineering & computing 16 (1978), S. 623-632 
    ISSN: 1741-0444
    Keywords: Performance evaluation of drugs and cosmetics ; Skin impedance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Sommaire De nombreuses études ont déjà été effectuées sur les applications de la mesure de l'impédance aux variations de paramètres biologiques. La base de ces mesures est la différence due au facteur objectif entre l'impédance de référence (qui ne contient pas de facteur objectif) et l'impédance qui le contient. Dans le passé, les efforts ont surtout porté sur la relation entre le changement d'impédance de la peau et les facteurs objectifs tels que des maladies, et seules quelques études ont porté sur ce principe de mesure pour établir une impédance de référence en vue d'une méthode d'analyse de données. L'article propose: (a) une méthode pour la détermination d'un niveau de référence basée sur la transformation d'identité de l'impédance de la peau, (b) une théorie de transformation linéaire pour l'analyse des données et (c) le triangle exprimant le taux de changement des résultats obtenus, et il établit un principe de base des mesures. L'évaluation de performances de cosmétiques a été effectuée pour donner un exemple d'application du principe.
    Abstract: Zusammenfassung In den letzten Jahren wurden zahlreiche Untersuchungen der Anwendung von Hauptimpedanz auf biologische Messungen durchgeführt. Die Basis für dieses Veifahren ist, daß zwischen einer Referenzimpedanz und der Impedanz ein Unterschied entsteht. In der Vergangenheit wurde die Wichigkeit der Relation zwischen einer Veränderung in der Hautimpedanz und den objektiven Faktoren, wie Z.B. Krankheiten, betont, und es gibt nur wenige Studien über das Meßprinzip, die Bestimmung der Referenzimpedanz und Datenauswertungsmethode. (a) Eine Methode zur Festlegung eines auf der Identitätstransformation der Hautimpedanz basierenden Referenzniveaus, (b) lineare Transformationstheorie zur Datenanalyse und (c) ein Grundprinzip zum Messen wurden erarbeitet. Als Anwendungsbeispiel dieses Prinzips wurde eine Leistungsbewertung für Kosmetika durchgeführt.
    Notes: Abstract Numerous studies have been carried out on the application of skin impedance to biological measurement. Measurement is possible because a difference will result due to the objective factor of the impedance, and the reference impedance (which does contain the objective factor). Emphasis has been placed, in the past, on the relationship between the change in skin impedance and objective factors such as disease, and there are only a few studies on the principle of measurement as the establishment of a reference impedance and a data-analysis method. (a) A method for setting a reference level based on identity transformation of skin impedance, (b) linear-transformation theory for data analysis, and (c) rate of change triangle expression of the results obtained, are proposed, and a basic principle of measurement has been established. Performance evaluation of cosmetics was carried out as an example of the application of this principle.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 351-358 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The amine functionalization of an acrylamide copolymer was achieved via Hofmann degradation. The starting material, poly(acrylamide-co-methyl methacrylate), was synthesized by radical precipitation polymerization. Using this copolymer, Hofmann degradation at 0°C in a water-dioxane mixture was done using sodium hypochlorite and NaOH. The resulting hydrogel could be dissolved in water-tetrahydrofuran mixtures, and the cast film had a water content of 73%. It was found that the conversion to primary amine was lower, and the extent of a side reaction was higher, compared to those of an acrylamide homopolymer. This was presumed to be due to the lack of the neighboring group effect among acrylamide units since it was a random copolymer. Further modification of this polymer by reacting the amine group is considered to obtain the desired properties for biomedical applications. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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