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  • Springer  (56)
  • Wiley-Blackwell  (9)
  • 1975-1979  (24)
  • 1970-1974  (11)
  • 1965-1969  (30)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 48 (1977), S. 137-144 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is shown that the erratic changes of the orbital period, which are observed in some detached eclipsing binary systems, cannot be interpreted as real if their light curves show changing anomalies with asymmetric minimum profiles. In this case the photometrically determined times of the minima do not coincide with the ideal geometric ones, which are unobservable. This fact and the applied reduction methods for deriving the photometric times of minima cause systematic period errors of cumulative character. The discussion of six photoelectrically-determined minima obtained within the last 20 yr, and earlier photographic ones of the 0d.479 period eclipsing binary XY UMa yields a constant period. The long cyclic light curve variations due to starspot activity of the larger and hotter component of this system are reflected in corresponding period oscillations.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 52 (1977), S. 351-356 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract On three nights in February 1976 we carried out polarimetric measurements, in V, of the short periodic eclipsing binary XY UMa, covering a complete cycle. The results are as follows: (1) Within all phase intervals the linear polarization does not exceed 0.1%. (2) In the phase range 0 p .95–1 p .35 the scatter of the Stokes parametersQ andU is about twice that within the phase interval 0 p .35–0 p .95. (3) A periodogram analysis of these data revealed a period of 21000 s, which is equal to half the orbital periodP o=0d.47899 within 1.5%. From these we derive the conclusions that no circumstellar envelope can be made responsible for the observed long-term changes of the light curve and system brightness, supporting the earlier spectroscopic finding. The different scatter of the Stokes parameters at different phase intervals and theP o/2 periodicity are in favor of the star spot model for XY UMa proposed by one of the authors (E. G.).
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 98 (1967), S. 852-873 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract The formation of benzotropolone compounds from catechol and pyrogallol derivatives depends upon the type, size, and position of the substituents in the reactants. Electrophilic substituents can be installed only in the 5-position of pyrogallol without loosing the capability of forming benzotropolones. This behavior is explained by the symmetrical electronic structure of the anion acting as 1.3-dipole. Pyrogallols, substituted in the 4- and 6-position by either methyl-, ethyl- or phenyl-groups, yield benzotropolones with 3-methoxy-o-benzoquinone. Isopropyl- andtert. butyl-groups in the same positions hinder benzotropolone formation because of steric hindrance. It was attempted to clarify the effect of the factors on the reaction mechanism by analysis of mixtures of benzotropolones, formed by oxidative coupling of catechol derivatives with pyrogallol-derivatives. On account of deficient yields this could not be done.
    Notes: Zusammenfassung Die Benzotropolonbildung aus Brenzcatechin- und Pyrogallolderivaten hängt von Art, Größe und Stellung der Substituenten in den Reaktionspartnern ab. Nur in die 5-Stellung des Pyrogallols können elektrophile Substituenten eingebaut werden, ohne daß die Fähigkeit zur Benzotropolonbildung verlorengeht. Dieses Verhalten wird durch die Symmetrie der elektronischen Struktur des als 1,3-Dipol wirkenden Anions erklärt. In 4- und 6-Stellung durch Methyl-, Äthyl- und Phenylgruppen substituierte Pyrogallole liefern mit 3-Methoxy-o-benzochinon Benzotropolone; Isopropyl- undtert. Butylgruppen in den gleichen Positionen verhindern aus sterischen Gründen die Benzotropolonbildung. Es wird versucht, aus der Produktanalyse von Benzotropolongemischen, die durch oxydative Verknüpfung von Brenzcatechinderivaten mit Pyrogallolderivaten hervorgegangen sind, Einblick in die den Mechanismus bestimmenden Faktoren zu erhalten. Verbindliche Aussagen hierüber werden durch die mangelhaften Stoffbildungen unmöglich gemacht.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 34 (1978), S. 363-364 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rapid loss of cochlear microphonics in guinea-pigs previously exposed to high-energy impulse noise was shown to be related to the breakdown of the endolymphatic boundary. The cochlear duct was rendered leaky by deterioration of the reticular membrane, and damage of sensory and supporting cells.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 26 (1970), S. 770-771 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung An der Oberfläche isolierter Glomerulus-Basalmembranen des Schweins konnten durch Gefrierätzung und durch Negativkontrastierung unregelmässig verteilte Partikel nachgewiesen werden. Sie werden als Reste der Glycocalyx von Endothel- beziehungsweise Epithelzellen angesehen und zeigen einen partikulären Aufbau dieser Kohlenhydratschicht an.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 52 (1965), S. 14-15 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    International journal of earth sciences 56 (1967), S. 973-992 
    ISSN: 1437-3262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Abstract The facies development of the Jurassic in the subbetic realm of Spain shows many common features on the whole in spite of differences in detail. “Neritic limestone facies“ may be distinguished from “Nodular limestone facies“ and “Limestone-marl-facies“. This paper deals with the stratigraphie range of red nodular limestones and “Limonite Crusts“ as equivalents of the celtiberic “Boundary Oolites“. The occurrence ofNucleata, Pygope andPosidonia in the Subbetic is discussed. There are certain facies relations to the Jurassic of the adjacent celtiberic area and especially to the Jurassic of the Western and Southern Alps.
    Abstract: Résumé Les faciès dans le Jurassique subbétique montrent, malgré des différences dans les détails beaucoup de traits communs. Il faut cependant distinguer entre le « faciès des calcaires néritiques», le « faciès des calcaires noduleux» et le « faciès des marnes et calcaires». La distribution stratigraphique des calcaires noduleux rouges et des « croutes de limonite», qui représentent les équivalents des «oolites limitrophes» celtibériques, est discuté. On commente alors l'existence deNucleata, Pygope etPosidonia dans le Subbétique. On peut constater des relations plus ou moins nettes non seulement avec le Jurassique celtibérique, mais aussi, avant tout, avec le Jurassique alpin occidental et méridional.
    Notes: Zusammenfassung Die fazielle Entwicklung des subbetischen Juras weist trotz Differenzierung im einzelnen viele gemeinsame Züge auf. Grundsätzlich ist aber zwischen einer „Neritischen Kalk-Fazies“ einer „Knollenkalk-Fazies“ und einer „Kalk-MergelFazies“ zu unterscheiden. Auf die stratigraphische Verbreitung der Roten Knollenkalke und die „Limonitkrusten“ als Äquivalente der keltiberischen „Grenzoolithe“ wird näher eingegangen, das Auftreten vonNucleata, Pygope undPosidonia im subbetisehen Jura besprochen. Sowohl zum benachbarten keltiberischen Jura als auch zum west- und südalpinen Jura sind mehr oder weniger deutliche Beziehungen vorhanden.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Mycopathologia 68 (1979), S. 171-174 
    ISSN: 1573-0832
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A case of an acute pulmonary paracoccidioidomycosis following the use of immunosuppressive therapy in a solid cancer patient is reported.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 116 (1978), S. 181-197 
    ISSN: 1420-9136
    Keywords: Electromagnetic field ; Vertical magnetic dipole ; Thin conductive sheet ; Lateral conductivity variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract An analytical formulation is developed for the resultant electromagnetic field of an oscillating vertical magnetic dipole located over a thin conductive sheet of infinite extent. The sheet is characterized by a conductivity-thickness product or conductance σd that may be a function of the horizontal coordinates. The system of integral equations arising in the general formulation is simplified greatly when azimuthal symmetry prevails. Numerical results for a Gaussian variation of σd in the radial direction are presented for the case of a symmetrically located source. These results are for the fields at the level of the source dipole over the conductive sheet. It is shown that the quadrature response of the sheet is enhanced when there is rapid variation of the conductance. The null in the resultant wave tilt is also found to be shifted toward the direction of increasing conductance.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 50 (1977), S. 261-270 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung An der Erythrocytenmembran wird die Beziehung zwischen anisotroper Toluidinblaufärbung und Membranstruktur untersucht. Enzymatischer oder chemischer Abbau der Glykokalyx stört die topo-optische Färbung. Eine Abschwächung wird auch durch Digitoninbehandlung Glutaraldehyd-fixierter Zellen erzielt. Durch Chloroform-Methanol-Inkubation wird die anisotrope Toluidinblaufärbung gelöscht, aber sie kann nach Aldehyd-Bisulfitbildung wieder nachgewiesen werden. An agglutinierten Erythrocyten ist die Wirkung einer Chloroform-Methanol-Behandlung stark eingeschränkt. Die reversibel kollabierte Glykokalyx zeigt keine topo-optische Färbung. Die Befunde werden als Hinweis auf die Bedeutung der räumlichen Orientierung der Glykoproteine an der Zelloberfläche gedeutet. Störungen im Aufbau der Glykokalyx durch Hydrolyse bzw. Verlust oder durch Umverteilung von Komponenten verändern die Bedingungen für die anisotrope Toluidinblaufärbung. Eingriffe an der Lipidschicht können mit solchen Veränderungen einhergehen; für die Interkalation von Farbstoffmolekülen in die Lipidschicht ergab sich jedoch kein Anhalt. Die topo-optische Färbung mit Toluidinblau wird auf Grund dieser Ergebnisse als geeignetes Verfahren zur Untersuchung der Glykokalyx von Erythrocyten (und vermutlich auch anderer Zellen) angesehen.
    Notes: Summary The study was concerned with the molecular structure of the erythrocyte membrane and its anisotropic staining with toluidine blue. Enzymatic or chemical degradation impairs the topo-optical staining. Decreased anisotropy results also from digitonin treatment of glutaraldehyde fixed cells. Incubation in a mixture of chloroform and methanol abolishes the anisotropic staining with toluidine blue, but it has been restored by the aldehyde bisulfite-procedure. The efficacy of a treatment with chloroform-methanol is greatly reduced in the case of agglutinated erythrocytes. The reversibly collapsed glycocalyx is devoid of topo-optical staining. The findings refer to the spatial orientation of glycoproteins at the cell surface. Degradation or loss and rearrangement, respectively, change the glycocalyx structure and likewise deteriorate the conditions for the anisotropic staining. Alterations of the lipid layer of the membrane may result in similar effects. There was, however, no indication of an intercalation into the lipid layer of dyestuff molecules. In conclusion, the topo-optical toluidine blue staining is considered a powerful method aiding studies of the glycocalyx of erythrocytes (and presumably of other types of cells too).
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