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  • 1975-1979  (4)
  • Analytical Chemistry and Spectroscopy  (3)
  • Adhesive organs  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 200 (1979), S. 453-473 
    ISSN: 1432-0878
    Keywords: Metamorphosis ; Settlement ; Morphogenetic movements ; Adhesive organs ; Ascidians
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cup-shaped adhesive papillae of Distaplia occidentalis evert at the onset of metamorphosis and each transforms into a hyperboloidal configuration. The rate of transformation is a function of temperature. At 14° C complete eversion takes about 30 seconds. Myoepithelial cells that extend from the rim to the base on the cup contract. Simultaneously the central part of the papilla advances 60–70 μm. During the last phases of eversion, collocytes (cells that secrete adhesives) on the inner wall of the cup and on the sides of the axial protrusion flow outward and form a collar-like structure. The myoepithelial cells contain arrays of thick and thin filaments. These become compacted during contraction. The surfaces of these cells become extensively folded as they shorten to about 1/3 of rest length. According to the proposed model the myoepithelial cells are the driving force in papillary eversion. Immediately after eversion is completed the papillae begin to retract. Eversion of the papillae is not inhibited by cytochalasin B, but the process of retraction is reversibly inhibited. Some histological characteristics of five types of everting papillae in four families of ascidians are compared.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 9 (1977), S. 589-592 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The carbon-fluorine coupling constants in 33 different substituted benzotrifluorides (trifluoromethyl-benzenes) have been determined. The 3J(CF) to the ortho aromatic ring carbons varied between 1.7 and 5.6 Hz and, in a given molecule, were always larger than the 5J(CF) to the para carbon, which ranged between 0.7 and 1.7 Hz. Coupling to the meta carbons, 4J(CF), was not observed and is under 0.3 Hz.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 196-197 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical ionization induced fragmentations (with 2-methylpropane as reagent gas) of 4-methyl- and 4,5-dimethyl-2-phenyl-1,3,2-dioxaborolane and 4-methyl-2-phenyl-1,3,2-dioxaborinane gave in each case two fragments, a hydrocarbon ion and metaboric acid. Propeae and thence metaboric acid are eliminated from 4,6-dimethyl-2-phenyl-1,3,2-dioxaborinane. The mechanisms of the fragmentations are discussed. Under the conditions used 2-phenyl-1,3,2-dioxaborolane and 2-phenyl-1,3,2-dioxaborinane do not fragment.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 507-511 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Consequential upon determinations of kinetic rate constants of ion/molecule reactions in methane and isobutane, simple equations are presented from which the pressures of methane and isobutane in the ion source of chemical ionization mass spectrometers can be calculated. Account is taken of the design of the ion source and it is only necessary to determine two ion currents for each gas.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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