Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1975-1979  (14)
  • 1970-1974  (2)
  • 1955-1959  (2)
Datenquelle
Materialart
Erscheinungszeitraum
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Ion transport through liquid membranes facilitated by crown ethers and their polymers (1974)
    Springer
    The journal of membrane biology 18 (1974), S. 379-397 
    Details
    ISSN: 1432-1424
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary The macrocyclic polyethers 4′-methylbenzo-15-crown-5 (15C5) and 4′-methylbenzo-18-crown-6 (18C6) as well as the corresponding crown polymers and crown-styrene copolymers were used as carriers for the transport of sodium and potassium picrate or the corresponding chlorides across a stirred, chloroform membrane. The observation of pronounced bathochromic shifts in the optical spectra of picrate salts on increasing the interionic ion pair distance could be utilized in determining the nature and structure of the migrating species. These species were found to be ion pair crown complexes of at least two kinds, viz., crown-complexed tight ion pairs and crown-separated ion pairs. The feasibility to thus identify the detailed structure of the migrating ionic entity is important as solvents of low polarity such as chloroform or hexane have been used as liquid membranes to represent the interior of biomembranes. The structure of the ion pair is expected to be an important consideration in correlating properties such as membrane potentials or cation selectivities with ionic distribution equilibria. Ion pair extraction equilibrium constants were determined in the H2O−CHCl3 system for the various crown species. The values for 18C6 with sodium and potassium picrate are nearly the same as those for the corresponding polymers. The same was found with 15C5 and sodium picrate; but the potassium forms, in addition to a 1∶1 complex, a 1∶2 complex with 15C5, making the corresponding polymer a more effective extracting agent. The ionic distribution data were interpreted in terms of the salt partition coefficients and the complex formation constants of the ion pair crown complexes in chloroform. The salt migration across the liquid membrane was found to be controlled by the diffusion of the ion pair complex in the chloroform, the extraction equilibrium across the interphase being rapidly established. The thickness of the diffusion layer adjacent to the water-chloroform interphase was estimated to be 50 μ. The ratios of the salt fluxes under otherwise identical conditions were found to be governed by the extraction equilibrium constants, the selectivity ratio for the potassium-to-sodium picrate with 18C6 being 118. This ratio, which was also determined for other crown species, was found to be anion dependent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01870124
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Disorders produced during high-current and high-dose phosphorus ion implantation in silicon (1979)
    Springer
    Applied physics 20 (1979), S. 225-229 
    Details
    ISSN: 1432-0630
    Schlagwort(e): 61.70 ; 61.80
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract Transmission electron microscopy, optical reflection and channeling effect measurements are employed to investigate disorders in 30 keV, high dose (3×1016ions/cm2) and high current (≦5 mA) phosphorus as-implanted silicon with (111), (100), and (110) orientation as a function of temperature rise (100–850°C) by the beam heating effect during implantation. Temperature rise below 400°C results in continuous amorrphous layer formation. This contrasts with results of the recovery into single crystals for temperature rise samples above 500°C, regardless of wafer orientation. Secondary defects (black-dotted defects, dislocation loops and rodlike defects) are formed in singlecrystal recovery samples, having a deeper distribution in (110) wafers and a shallower distribution in (111) and (100) wafers. Rodlike defects observed in 850°C samples are of “vacancy” type and have the largest density in (110) wafers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00886022
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Electron microscopy study of ordering of potassium ions in cubic KSbO3 (1978)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 34 (1978), S. 625-634 
    Details
    ISSN: 1600-5724
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: Ordered and disordered states of potassium ions in (111) tunnels in the structure of cubic KSbO3 have been studied by high-resolution electron microscopy. N-beam calculations for the images of both the ordered and disordered states reproduce well the observed images. The disordered state changes into the ordered state under electron irradiation during the observations. Electron diffraction from the specimens and optical diffraction from the images show diffuse spots due to small domains of the long-range-ordered state, but no other diffuse scattering due to short-range order has been observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1107/S0567739478001291
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Electron-microscope study of the crystal structures of mixed oxides in the systems Rb2O–Ta2O5, Rb2O–Nb2O5 and K2O–Ta2O5 with composition ratios near 1:3. I. Stacking characteristics of MO6 layers (1978)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 34 (1978), S. 765-773 
    Details
    ISSN: 1600-5724
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: The crystal structures of phases, previously designated as 11L, 9L and 16L, which were commonly found in the title systems are suggested from their high-resolution two-dimensional electron-microscope images. Two types of blocks are found which are composed of five and six layers of pentavalent-metal oxide octahedra and are closely related to the pyrochlore structure. The 11L structure is of rhombohedral {\tt ABCABC} stacking of the former type of block, and the 9L structure is of hexagonal {\tt B}_{0}{\tt A}_{0}^{\prime}{\tt B}_{0}{\tt A}_{0}^{\prime} stacking of the latter type of block. The 16L structure is found to be an alternate stacking of the two types of blocks. The method of stacking of the blocks is the same for the three structures and is found to be favorable from the point of view of local charge balance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1107/S0567739478001588
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Electron-microscope study of the crystal structures of mixed oxides in the systems Rb2O–Ta2O5, Rb20–Nb2O5 and K2O–Ta2O5 with composition ratios near 1:3. II. Various intergrowth phases and two-dimensional ordering of pentavalent ions (1978)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 34 (1978), S. 773-781 
    Details
    ISSN: 1600-5724
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: In part I, the preceding paper, structural models were proposed on the basis of high-resolution electron microscopy for phases previously designated as 11L, 9L and 16L, which were found to exist in the title systems. Two types of blocks were found, which are composed of five and six layers of octahedra. In the present paper, various intergrowth phases which are composed of the two types of blocks are described. A new notation is proposed to denote these intergrowth phases as well as the 11L, 9L and 16L structures. Two-dimensional ordering of pentavalent ions in the six-layer block is found, giving rise to diffuse scattering in electron diffraction patterns. Two-dimensional images, calculated on the basis of the proposed model, are found to reproduce the observed images.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1107/S056773947800159X
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Separation of Flavins by Ion-Exchange Resins (1955)
    [s.l.] : Nature Publishing Group
    Nature 175 (1955), S. 555-556 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Using an anion-exchange resin, Cohn et ol. have reported the separation of adenosine and adenosine mono-, di- and tri-phosphates4, and that of choline and its ester6. For the separation of flavin compounds by ion exchange, several ion exchangers were examined, and the anion-exchange resin, ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/175555a0
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Uptake of 5-hydroxytryptamine by chick retina (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 30 (1978), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1978.tb07069.x
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Postnatal development of 5-hydroxytryptamine and monoamine oxidase in rat spinal cord (1976)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 27 (1976), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1976.tb01589.x
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    Interaction of chinoform with electron transfer system of rat liver microsomes (1974)
    Springer
    Cellular and molecular life sciences 30 (1974), S. 1430-1432 
    Details
    ISSN: 1420-9071
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Zusammenfassung Nachweis, dass Chinoform, 5-chloro 7-iodo 8-quinolinol, mit Mikrosomen der Rattenleber weder hydroxyliert noch dehalogeniert werden kann. Inkubation mit Chinoform vermindert die Komponenten des elektronischen Transfersystems, was auch mit in vivo-Versuchen festgestellt wurde.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01919678
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    Distribution of type A and B monoamine oxidase activities in the central nervous system of rat and chick (1976)
    Springer
    Cellular and molecular life sciences 32 (1976), S. 13-14 
    Details
    ISSN: 1420-9071
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of type A and B monoamine oxidase (MAO) activities in the central nervous system (CNS) of rat and chick was investigated using 5-hydroxytryptamine and β-phenylethylamine as specific substrates. The distribution of type A MAO was similar to that of type B MAO in rat CNS, but quite different in chick CNS. This may be ascribed to the difference in animal species. The major part of MAO activity in the spinal cord was found to be type A.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01932596
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...