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  • Electronic Resource  (16)
  • 1960-1964  (8)
  • 1955-1959  (7)
  • 1950-1954  (1)
Material
  • Electronic Resource  (16)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 75 (1953), S. 486-486 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 193 (1962), S. 941-942 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] CHROMATOGRAPHY on adsorbent-coated glass strips or plates is frequently used as a qualitative analytical method. We have modified the techniques described by Kirchner1 and Stahl2 to make it applicable for preparative purposes. The method compares favourably with column chromatography in many ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 15 (1962), S. 271-281 
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 159 (1960), S. 563-583 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In a previous paper direct electron-intensity measurements in Debye-Scherrer diagrams of aluminium have been described. A retarding field apparatus was used for investigations into the influence of crystal size and electron energy (15 to 50 keV) on the elastic diffraction intensities. The validity range of the kinematical theory could be determined. By means of a retarding field the inelastically scattered electrons were separated from the elastically scattered electrons (energy loss below 2 eV). In this paper the retarding field apparatus by which scattering intensities can be measured with good accuracy (≈ 2%) is described in detail. It is compared with other arrangements for the measurements of angular and energy distributions of scattered electrons.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 143 (1955), S. 17-30 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung Für Myonen beiderlei Vorzeichens wird die Streuverteilung bei Quecksilberkernen im Energiebereich von etwa 30 MeV angegeben. Die Berechnung geschieht mit Hilfe eines auf dieDirac-Gleichungen zugeschnittenen WKB-Verfahrens, wobei dessen Anwendbarkeit jedoch nicht auf den hier interessierenden schwach relativistischen Energiebereich beschränkt ist. Die für die beiden Kernradien 1,2 · 10−13 ·A 1/3 cm und 1,4 · 1013 ·A 1/3 cm gefundenen Ergebnisse lassen es sinnvoll erscheinen die zum Problem der Größe des Kernradius ausgeführten Experimente durch Streuversuche mit Myonen zu ergänzen, falls es möglich wird in dem genannten Energiebereich mit ausreichender Teilchenstromdichte und Energiehomogenität zu experimentieren.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 44 (1957), S. 449-449 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 201 (1964), S. 315-315 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1. Psammechinus miliaris, 16 h gastrula, 2 cells of the oral field. n, nucleus; m, mitochondrium; y, yolk sphere. The arrows indicate the elongated tips of the inner surface of the cells, (× c. 11,700) Examining thin sections of 16-h gastrulse of Psammech-inus miliaris in search of specific ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 2 (1955), S. 163-171 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary 1. The male ofAnergates shows a reduction of some parts of the digestive system and the musculature of the skeleton. The volume of the brain is reduced by reduction of association centres. The anatomy of the female corresponds to a free-living species, only the stinging apparatus cannot be found. 2. During the reproductive phase a remarkable enlargement of all somatic cells takes place due to polyploidy with exception of the nervous system. To strengthen the exoskeleton the intersegmantal membranes are hardening. 3. As result of isolation ofAnergates certain analogies to regressive evolution of some cave animals are noted.
    Abstract: Résumé 1o Le mâle d'Anergates présente une réduction de la musculature squelettique et de quelques parties du tractus digestif. Le volume des ganglions cérébroïdes est diminué par suite de la réduction des centres d'association. L'anatomie de la femelle rappelle celle des femelles sauvages, à ceci près que l'aiguillon et ses annexes sont absents. 2o A part les cellules nerveuses, toutes les cellules somatiques de l'image subissent une croissance remarquable à cause de leur polyploïdie. Les membranes intersegmentales se durcissent et renforcent l'exosquelette. 3o Eu égard à l'isolement d'Anergates, on peut constater certaines analogies entre les phénomènes régressifs qu'il présente et ceux rencontrés chez des animaux cavernicoles.
    Notes: Zusammenfassung 1. Beim ♂ vonAnergates ist neben Teilen des Darmtraktes besonders die Skelettmuskulatur zurückgebildet. Das Gehirnvolumen wurde auf Kosten der assoziativen Zentren herabgesetzt. Der Bau des ♀ entspricht dem einer freilebenden Art, lediglich der Stachelapparat ist nicht mehr nachweisbar. 2. Postimaginal findet beim ♀ eine auffallende Vergrößerung aller Somazellen statt, für die — mit Ausnahme des Nervensystems — Polyploidisierungsvorgänge verantwortlich sind. Zur Festigung des Exoskeletts verhärten die Intersegmentalhäute. 3. Als Folge der Isolierung vonAnergates sind gewisse Analogien zur regressiven Evolution mancher Höhlentiere festzustellen.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Morphological manifestations of the chromosomal metabolism have been found in the first spermatocyte nucleus of Drosophila melanogaster. These “metabolic structures” include several types of well defined components, among which the „tubuli“ and the „reticular elements“ are most conspicuous. The metabolic nature of these elements follows from their phase specifity and from cytochemical data. 2. Masses of tubuli of 300–400 Å diameter are found all over the meiotic prophase chromosomes in the spermatocyte nucleus, but not in the spermatogonial nucleus. The reticular elements appear somewhat later and usually form a single group. Both types of metabolic structures are decomposed during diakinesis when they separate from the chromosomes. 3. The tubuli are mainly composed of a basic protein. In addition they seem to contain RNA. The presence of DNA in small concentration can not yet be excluded. 4. The chromosomal origin of the tubular as well as the reticular elements follows not only from the observed contact with the chromosomes but also from the fact that spermatocyte nuclei of X/O-males of Drosophila melanogaster do not contain these components. This shows that the Y-chromosome is involved. 5. The role of the Y-chromosome in the formation of the metabolic structures has been further elucidated by studying males with partial Y-chromosomes, such as YS, YL, and Y″. Spermatocytes with the long arm of the Y (X/YLc) as a rule contain tubular and reticular elements in nearly normal quantity. X/YS and X/Y″ testes show a highly variable pattern. Some spermatocyte nuclei resemble the X/O-type while the rest represent all intermediate stages between the X/O- and the X/YL-type. 6. The lack of tubuli in X/O or in X/YS and X/YL spermatocyte nuclei is always correlated with the appearance of crystal needles in the nucleus as well as in the cytoplasm. Only very rarely in X/YS spermatocytes is an intranuclear crystal found together with a small amount of tubuli. The X/O crystal needles persist during spermatogenesis and are still found in sperm bundles. The crystal material seems to be a protein which is different from the tubular protein. 7. The possibilities of the involvement of the Y-chromosome in the formation of the metabolic chromosomal structures are discussed. It seems probable that tubuli represent a highly modified state of the Y-chromosome, or parts of this chromosome. The formation of protein crystals in X/O-spermatocytes indicates the presence of a biochemical block. The relation to fertility i.e. sperm motility is unclear. X/YL males do not produce motile sperms although tubuli are regularly present in spermatocyte nuclei.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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