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  • Springer  (19)
  • 1970-1974  (19)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 1 (1973), S. 36-47 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Oral administration of two isomeric tetrachlorobiphenyls (TCBs) (2, 3, 4, 5-and 3, 5, 3′, 5′-tetrachlorobiphenyls) to rats at three dosage levels does not cause any adverse effect on their growth. However, several hepatic enzyme systems are affected, even at the lowest level (5 mg/kg). EthylmorphineN-demethylase and aniline hydroxylase activities are slightly induced by 2, 3, 4, 5-TCB but, at a medium dose level (20 mg/kg), the activity ofpara-nitroanisoleO-demethylase is induced two-fold. Also, 3, 5, 3′, 5′-TCB induces these enzyme systems in male rats but decreases the activities of aniline hydroxylase and ethyl morphineN-demethylase in female rats at higher doses. An extra polar metabolite occurs in thein vitro metabolism of oestradiol-3H when female rats are treated with 2, 3, 4, 5-TCB at a dosage level of 40 mg/kg. UDP-Glucuronyl/transferase and δ-aminolevulinic acid synthetase activities are not affected by the administration of these two TCBs.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 1 (1973), S. 245-254 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Mirex (dodecachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalene) was orally administered to male and female rats at daily dosages of 5, 10, 25, and 50 mg/kg for 5 days and its effects on aniline hydroxylas,p-nitroanisoleO-demethylase, ethyl morphine-N-demethylase, and UDP-glucruonyltransferase activities in the liver were studied. Liver-to-body weight ratios show significant increases at all of the doses tested, reaching maximum of 206 and 230 per cent of controls at a dose of 25 mg/kg for males and females, respectively. Metabolism of each of the substrates is altered by each dose of mirex fed. Aniline hydroxylase activity is decreased at all levels tested and the reduction is progressive with the dose. The Mirex content of rat liver microsomes is, by analysis, 9.69, 14.75, and 36.73 µg per 0.2gram-equivalents of liver microsomes from male rats treated at 10, 25, and 50 mg/kg, respectively. Aniline hydroxylase activity is not affected by addition of up to 400 µg of mirex to the reaction mixtures, using liver preparations from untreated animals.p-Nitroanisole demethylation activity is induced to a maximum in animals treated at 5 mg/kg. Ethyl morphine demethylase is induced to a maximum by 10 mg/kg in male and 25 mg/kg in female rats. Higher doses manifest a reversal ofp-nitroanisole-and ethyl morphine demethylase activities in both the sexes. Although the UDP-glucuronyl transferase specific activity is unaffected by mirex pretreatment, total activity in the liver increases to a maximum of 173 and 149 percent of controls at 25 mg/kg in males and females, respectively. Thus, it appears that chronic low doses of mirex seriously alter hepatic mixed-function oxidase systems of exposed animals, although mirex is not a substrate for any of these enzymes.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 29 (1973), S. 233-235 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Elektronenmikroskopische Untersuchungen des Analorgans bei Drosophilalarven zeigten, dass die cuticulare Oberfläche dieses Organs durch Einstülpungen der Epicuticula vergrössert wird. Die an die Cuticula angrenzende Plasmamembran der Hypodermiszellen bildet zahlreiche Faltungen. Je nach der Salinität des Aussenmediums weist die Anzahl der Plasmamem-branfaltungen und der im Cytoplasma lokalisierten Mitochondrien regulatorische Veränderungen auf.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 165 (1970), S. 132-149 
    ISSN: 1432-041X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung 1. Mittels Polyacrylamidgel-Elektrophorese wurden die Serumproteine der metamorphosierenden Larven und adulten Tiere vonRana temporaria, Bombina variegata, Bufo bufo undTriturus alpestris aufgetrennt. Auf Grund der Ergebnisse verschiedener spezifischer Färbemethoden konnte das Vorkommen von Albumin, Transferrin, Glycoprotein, Lipoprotein und möglicherweise Haptoglobin nachgewiesen werden. 2. Im allgemeinen werden die elektrophoretischen Muster mit fortschreitender Metamorphose komplizierter. Eingehende Analysen bewiesen, daß neue Serumproteine während der Metamorphose und der adulten Reifung auftreten. 3. Bei allen drei Anurenarten nimmt die Totalkonzentration der Serumproteine im Laufe der Metamorphose rasch zu. Die Albuminfraktion zeigt die höchste Syntheserate, so daß das Verhältnis Albumin zu Globulin gegen Abschluß der Metamorphose eine zwei- bis fünffache Erhöhung aufweist. Während des adulten Wachstums bleibt dieses Verhältnis konstant trotz einer weiteren Zunahme der Totalkonzentration. Ähnliche Veränderungen des Proteinmusters konnten bei jungen Larven vonR. temporaria undB. bufo, die mit Thyroxin behandelt worden waren, festgestellt werden. 4. Im Gegensatz zu den drei Anuren zeigtT. alpestris eine viel geringere Zunahme der Totalkonzentration der Serumproteine und keine Veränderung des Verhältnisses Albumin zu Globulin während der Metamorphose. Andererseits konnte eine maximale Zunahme des Proteins in der Gelregion einiger Globulinfraktionen, die eine relativ langsame Anodenbeweglichkeit besitzen, beobachtet werden. 5. Die stoffwechselphysiologischen und molekularen Aspekte der Veränderungen des Serumproteinmusters während der Metamorphose bei Amphibien werden diskutiert.
    Notes: Summary 1. Serum proteins in the metamorphosing larvae and adult animals ofRana temporaria, Bombina variegata, Bufo bufo andTriturus alpestris were separated by polyacrylamide gel electrophoresis. Based on various specific staining reactions the occurrence of albumin, transferrin, glycoprotein, lipoprotein and possibly haptoglobin was identified. 2. In general, the electrophoretic patterns become increasingly more complex with the progress of metamorphosis. Detailed analyses revealed the appearance of various new serum proteins both at the time of metamorphosis and during adult maturation. 3. In all three anuran species there is a rapid increase in the total serum protein concentration as metamorphosis proceeds. The albumin fraction shows the highest increasing rate, resulting in a two- to fivefold increase of the albumin/globulin ratio with the completion of metamorphosis. During postmetamorphic growth this ratio remains constant in spite of the continuous rise of the total concentration. Similar changes of the serum protein pattern have been observed in premetamorphic larvae ofR. temporaria andB. bufo treated with thyroxine. 4. T. alpestris differs from the three anurans in having a much smaller increase of the total serum protein concentration and showing no change of the albumin/globulin ratio at metamorphosis. Instead, a maximum increase of protein in the gel section of relatively slow anodal-moving globulins was observed. 5. The metabolic and molecular aspects of the changes of serum proteins during amphibian metamorphosis are discussed.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica 17 (1973), S. 17-24 
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung In dieser Arbeit wird gezeigt, daß die Amplitude der in einem inhomogenen, elastischen, Wärme nicht leitenden Werkstoff sich ausbreitenden Beschleunigungswellen derBernoulli-Gleichung genügt und daß die Kenntnis der lokalen isentropen elastischen Eigenschaften ausreicht, um das Amplitudenverhalten zu bestimmen. Betrachtet wird außerdem die Anwendung der allgemeinen Ergebnisse auf den Spezialfall eines in bezug auf ein spezielles inhomogenes Bezugssystem in Ruhe befindlichen Körpers. Für diesen Spezialfall wird gezeigt, daß für verschiedene Materialeigenschaften die Amplituden vollständig verschiedenes Verhalten zeigen können.
    Notes: Summary In this paper, it is shown that the amplitude of an acceleration wave propagating in an inhomogeneous elastic non-conductor of heat obeys the well-known Bernoulli equation, and that knowing its local isentropic elastic properties is sufficient to predict the behavior of the amplitude. A specific application of the general results to the case when the material is at rest in a non-homogeneous reference configuration is also considered; it is shown that the specific behavior of the amplitude for this case can be quite different, depending on the properties of the material in this configuration.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica 17 (1973), S. 247-253 
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung In dieser Arbeit wird die das Verhalten von in inhomogenen thermoelastischen Körpern sich ausbreitenden Stoßwellen charakterisierende Differentialgleichung abgeleitet. Die Folgerungen auf das lokale Verhalten der Amplituden wird untersucht. Es wird gezeigt, daß das Verhalten von der relativen Größe einer Zahl λ, genannt kritischer Sprung des Verzerrungsgradienten, und dem Sprung im Verzerrungsgradienten über den Stoß abhängt.
    Notes: Summary In this paper, the differential equation governing the behavior of shock waves propagating in inhomogeneous thermoelastic bodies is derived. The implications of this equation on the local behavior of the amplitudes are examined. It is shown that the behavior depends on the relative magnitudes of a number λ, called the critical jump in strain gradient, and the jump in strain gradient across the shocks.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica 16 (1973), S. 21-33 
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Im Rahmen einer linearen Zwei-Temperatur-Theorie werden zwei Wellenausbreitungsprobleme untersucht. Besonderes Interesse gilt den Wellenausbreitungsgeschwindigkeiten, der Ausbreitung der Unstetigkeiten in den beiden Temperaturen und in der Verzerrung, sowie Lang- und Kurzzeitnäherungen. Zulässige Wellenausbreitungsgeschwindigkeiten und das Abklingverhalten von Unstetigkeiten werden auch durch Untersuchung von singulären Flächen gewonnen. Die Resultate stimmen mit denen für die beiden untersuchten Probleme gewonnenen überein.
    Notes: Summary Within the framework of a linear two-temperature theory two separate wave propagation problems are investigated. Interest is directed to wave speeds, travelling discontinuities in the two temperatures and the strain, and long and short time approximations. Admissible wave speeds and the decay of travelling discontinuities which are associated with this theory are also obtained from a singular surface analysis. The results agree with those reached in the solution of the specific boundary value problems considered.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica 15 (1972), S. 95-104 
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Diese Arbeit behandelt den Einfluß innerer Zustandsvariablen auf das Anwachsen bzw. Abklingen von Beschleuningungswellen von anisotropen nichtlinearen thermoelastischen Stoffen. Hinreichende Bedingungen für die Existenz einer ebenen longitudinalen und zweier transversaler Beschleunigungswellen mit orthogonalen Amplituden werden angegeben.
    Notes: Summary This work is concerned with the effect of internal state variables on the growth and decay properties of acceleration waves in anisotropic nonlinear thermoelastic materials. Sufficient conditions are given which insure the existence of a plane longitudinal acceleration wave and two transverse acceleration waves with orthogonal amplitudes.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Acta mechanica 19 (1974), S. 201-214 
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung In dieser Arbeit wird ein Gemisch chemisch reagierender Stoffe mit Gedächtnis betrachtet. Nach Formulierung der Werkstoffannahmen wird die übliche Annahme schwindenden Gedächtnisses getroffen, und die Einschränkungen für die Antwortfunktionen durch den 2. Hauptsatz werden ermittelt. Anschließend wird das Verhalten von Beschleunigungswellen in einem Gemisch, das sich anfänglich in thermodynamischem Gleichgewicht befindet, untersucht. Unterschieden werden die Fälle eines starken oder schwachen Gleichgewichtszustandes und das Wellenverhalten in diesen Fällen bestimmt.
    Notes: Summary In this paper we consider a mixture of chemically reacting materials with memory. After stating the constitutive assumptions we adopt the usual postulate of fading memory and determine the restrictions which the Second Law of Thermodynamics places on the response functions. Subsequently, we examine the behavior of acceleration waves propagating in such a mixture which is initially in a state of thermochemical equilibrium. We also distinguish between the cases when the equilibrium state is weak or strong, and determine their effects on the wave behavior.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Rheologica acta 9 (1970), S. 253-258 
    ISSN: 1435-1528
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Conclusion A set of consistent stress equations is available for stress prediction in a granular material bed under steady flow. Difficulties associated with boundary slope discontinuities can be handled by a careful selection of a characteristic pattern. If necessary, the characteristic pattern can be modified to give stress fields closer to those in practical systems. Solution of the stress equations is based on the well established method of integration along characteristics. The computation is quite involved but can be done on a digital computer. The difficulties in utilizing the results based on irregular characteristic grids can be solved by two dimensional interpolation to give values on rectangular grids. Extension of the technique to a more general system is possible, for example, a symmetric cylindrical bed, but in this case some extra information on the relation between the stress components is needed.
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