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  • 1985-1989  (3)
  • 1965-1969  (2)
  • 1955-1959  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Self-consistent calculations of tunneling currents in n+-GaAs/i- AlxGa1−xAs/n+-GaAs structures and comparison with measurements (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 3581-3588 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present calculations and measurements of current as a function of voltage I(V), and conductivity at low voltage as a function of temperature, G(T), for n+ -GaAs/i- Alx Ga1−x As/n+ -GaAs single-barrier tunneling structures. The current is modeled by its tunneling and thermionic emission components. The shape of the conduction-band edge is obtained by solving Poisson's equation self-consistently, together with two different models for the charge density. In the first model, the electron density is evaluated semiclassically, and in the second, the electron density is calculated from the electronic wave functions. Good agreement is obtained with both models between the experimental and the calculated I(V) and G(T) characteristics over the 4.2–200 K temperature range. The fits obtained are very sensitive to small variations (1%) in barrier width and effective barrier height, which allows one to determine these parameters within a narrower uncertainty range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.342488
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  • 2
    Electronic Resource
    Electronic Resource
    Die Gesamtcorticoide im Harn nach Staudinger-Bauer während des Kindesalters (1956)
    Springer
    Journal of molecular medicine 34 (1956), S. 469-472 
    Details
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Es wird über Erfahrungen mit der Corticoidbestimmungsmethode nachStaudinger undBauer berichtet. Mit diesem Verfahren werden die freien und conjugierten Corticoide gleichzeitig erfaßt. Ihr Ausscheidungsverhältnis beträgt etwa 1:9. Die Steroidwerte steigen mit dem Alter der Kinder kontinuierlich an. Nach den ersten Lebensjahren zeigen sie etwa gleichbleibende Relationen zu Körperoberfläche und -gewicht. Ein Vergleich der Corticoidwerte mit den ausgeschiedenen Harnmengen ergibt für die ersten Lebensjahre ein proportionales Verhalten der beiden Größen. Mit zunehmendem Alter vermindert sich diese Korrelation; die Steroidausscheidung wird unabhängiger vom Harnvolumen. Ursächlich kommen für diese Beziehungen sowohl eine gesteigerte adrenale Produktion wie eine verstärkte Clearance der Steroide unter dem Einfluß vermehrter Wasserzufuhr in Betracht. Wir möchten die zweite Erklärung für die wahrscheinlichere halten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01467313
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Retinoids inhibit the differentiation of embryonic-mouse mesenchymal cells in vitro (1985)
    Springer
    Archives of dermatological research 277 (1985), S. 98-104 
    Details
    ISSN: 1432-069X
    Keywords: Chondrogenesis ; Retinoids ; Differentiation ; Limb-bud mesenchyme ; In vitro
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of all-trans retinoic acid, 13-cis retinoid acic and two aromatic retinoids (Ro 10-1670, Ro 11-1430) on the chondrogenic differentiation of mesenchymal cells in vitro was studied electronmicroscopically. Organ cultures of limb buds from mouse embryos (Day 11) and high-density cultures of embryonic-mouse mesenchymal cells (Day 12) were used as experimental models. After a 6-day culture in the control medium, the development of hyaline cartilage was observed in both systems. In cultures which were treated with retinoids from Day 1 through Day 3 and then incubated in the control medium for 3 more days, the mesenchymal cells still maintained the morphological features of the blastema stage; cartilage synthesis was reduced (low retinoid concentrations) or completely absent (high retinoid concentrations). These findings indicate that the treatment of embryonic-mouse mesenchymal cells with retinoids induces a persistent and dose-dependent inhibition of chondrogenic differentiation, which in quantitative terms, is variably expressed during treatment with different retinoids. These inhibitory effects of retinoids on chondrogenesis are probably implicated in the pathogenetic mechanisms of their teratogenic action in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414105
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  • 4
    Electronic Resource
    Electronic Resource
    Elektronenmikroskopische Untersuchungen über die Wirkung von Bisolvon® auf das Lungenepithel von Hühnerembryonen in der Kultur (1969)
    Springer
    Lung 139 (1969), S. 170-182 
    Details
    ISSN: 1432-1750
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Deckglas-, Monolayer- und Stückkulturen vom Lungenepithel 9tägiger Hühnerembryonen wurden nach Zusatz von Bisolvon elektronenmikroskopisch untersucht. Diese Substanz wurde entweder fein verteilt oder gelöst den Kulturen in einer Menge von 10, 30, 100 oder 300 γ/ml Medium zugesetzt. Das planimetrisch bestimmte Epithelwachstum verändert sich bis 100 γ Bisolvon/ml Medium auch nach mehreren Umsetzungen ebensowenig, wie die Zahl der Epithelzellen und Mitosen pro Flächeneinheit. Das Wachstum der Fibroblasten wird jedoch bei höherer Dosierung in manchen Versuchen gehemmt. In den Deckglas- und Monolayer-Kulturen entwickeln sich unter Bisolvon Zellen, die den Nischenzellen in situ ähnlich sind. Erst nach 300 γ Bisolvon/ml Medium läßt sich im Epithel elektronenmikroskopisch eine Zellschädigung nachweisen. In der Stückkultur entstehen zahlreiche lysosomenähnliche Einschlüsse, deren Inhalt dosisabhängig verändert wird. Die Fähigkeit der Zellen in Richtung auf Nischenzellen (Deckglas- bzw. Monolayer-Kultur) bzw. Bronchialepithelzellen (Stückkultur) zu differenzieren, wird diskutiert. Damit kann ein Angriffspunkt des Bisolvon am lysosomalen Apparat der Bronchialepithelzellen und am AAF in den Nischenzellen vermutet werden.
    Notes: Summary The epithelium from the lungs of chicken embryos after incubation of 9 days had been studied in a Bisolvon containing culture-medium (cover-glass, monolayer- and organoid-culture). Bisolvon was added solved or insolved in a concentration of 10, 30, 100, or 300 γ per ml medium. The rate of growth determined from the number of cells and their mitoses per square had not been altered with Bisolvon concentrations as much as 100 γ per ml medium. With higher Bisolvon concentrations fibroblast mitosis number diminished in some experiments. In the cover-glass- and monolayer cultures a special type of cells is developing after Bisolvon treatment. These cells resemble the „Nischen“-cells (granular pneumocytes). If Bisolvon is added in a concentration of 300 γ per ml medium a damage of the epithelial cells is obvious with the electron microscope. In the organoid-cultures numerous lysosome-like organelles are found in relation to the dose of Bisolvon. The ability of the epithelial cells to develop towards „Nischen“-cells (cover-glass or monolayer-cultures) respectively towards the bronchial epithel cells (piece-cultures) is discussed. We suppose Bisolvon acts at the lysosomal apparatus of bronchial epithelium and at the antiatelectase factor (AAF) of the granular pneumocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02090946
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  • 5
    Electronic Resource
    Electronic Resource
    Das elektronenmikroskopische Bild der Epithelzellen aus embryonalen Hühnerlungen in der Gewebekultur (1969)
    Springer
    Lung 139 (1969), S. 155-169 
    Details
    ISSN: 1432-1750
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Epithelzellen aus den Lungen 9tägiger Hühnerembryonen wurden in Deckglas-, Monolayer- und Stückkulturen unter verschiedenen Bedingungen gezüchtet und licht- oder elektronenmikroskopisch untersucht. Mit den beiden ersten Kulturmethoden gelingt es, ein Epithelwachstum in zusammenhängenden Platten zu erreichen. Die Monolayer-Kulturen scheinen besonders brauchbar zu sein, da Epithel isoliert zu gewinnen ist und beim Wachstum auf organischen Filmen (Fibrin, Agar) auch eine Weiterverarbeitung in toto möglich ist. Elektronenmikroskopisch gelingt es, das Substrat der epithelialen Adhäsion genau darzustellen. Die in vitro-Epithelien werden morphologisch mit den Alveolardeckzellen in vivo verglichen und ihre Differenzierungsstufe diskutiert. — Die Epithelzellen in der Stückkultur sind noch nach 4 Tagen gut erhalten und damit als vital anzusehen.
    Notes: Summary Epithelial cells from the lungs of chicken embryos after 9 days incubation had been grown in culture and observed with the light- and electron microscope. We used cover-glass-, monolayer- and organoid-cultures in several culture-mediums. The epithelium grows in coherent plaques in cover-glass- and in monolayer-cultures. From the monolayer culture growing on fibrin or agar the epithelium is separated easily for subsequent experiments. With the electron-microscope we visualized the morphology of epithelial adhesions. The in vitro epitheliums are compared with in vivo alveolar lining cells morphologically and their stage of development in vitro is discussed. The epithelial cells in the organoid-cultures are preserved well even after four days of culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02090945
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  • 6
    Electronic Resource
    Electronic Resource
    Volume and surface of receptor and auxiliary cells in hygro-/thermoreceptive sensilla of moths (Bombyx mori, Antheraea pernyi, and A. polyphemus) (1989)
    Springer
    Cell & tissue research 255 (1989), S. 59-67 
    Details
    ISSN: 1432-0878
    Keywords: Thermoreceptors ; Hygroreceptors ; Sensillum styloconicum ; Sensillum-lymph space ; Morphometry ; Bombyx mori, Antheraea pernyi, A. polyphemus (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The thermo/hygroreceptive sensilla styloconica of the silkmoths Bombyx mori, Antheraea pernyi, and A. polyphemus were reconstructed from serial sections of cryofixed and chemically fixed specimens. The volume and surface area of the different sensillar cells were calculated from the area and circumference of consecutive section profiles. In addition, data are provided on the length and diameter of the outer and inner dendritic segments of the receptor cells. The morphometric data obtained from the three species are highly consistent and significantly different from those of olfactory sensilla trichodea of the same species. In each sensillum two type-1 receptor cells (hygroreceptors) are associated with one type-2 cell with a lamellated outer dendritic segment, a comparatively thick inner dendritic segment, and a particularly large soma (thermoreceptor). In contrast to olfactory sensilla, the thecogen cell is the largest auxiliary cell forming an extensive apical labyrinth bordering the inner sensillum-lymph space, whereas an inconspicuous trichogen cell and a medium-sized tormogen cell border a comparatively small outer sensillum-lymph cavity. Moreover, both sensillum-lymph spaces are separated from each other not only by the dendrite sheath, but also by the trichogen cell. The results are discussed with regard to recent electrophysiological observations and current hypotheses on the function of sensilla.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229066
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