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  • 1975-1979  (5)
  • 1960-1964
  • Analytical Chemistry and Spectroscopy  (3)
  • Settlement  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Larval adhesive organs and metamorphosis in ascidians (1979)
    Springer
    Cell & tissue research 200 (1979), S. 453-473 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00234856
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Larval adhesive organs and metamorphosis in ascidians (1977)
    Springer
    Cell & tissue research 183 (1977), S. 423-444 
    Details
    ISSN: 1432-0878
    Keywords: Ascidian larva ; Adhesive papillae ; Settlement ; Myoepithelial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The larva of Distaplia occidentalis bears three cup-shaped adhesive papillae, each with a prominent axial protrusion. At the onset of metamorphosis these organs rapidly evert through fenestrations in the cuticular layers of tunic exposing hyaline caps of adhesive. Additional adhesive material is secreted from collocytes during eversion. The stickiness of the papillae facilitates attachment to a variety of substrates. Each papilla is composed of more than 900 cells; six different types were identified. The wall of the cup contains about 260 myoepithelial cells with long attenuated processes. These extend from the rim of the cup to the base in the parietal (inner) layer. The apices of the myoepithelial cells are held in place by 11 pairs of specialized anchor cells bearing long bulbous microvilli. When the myoepithelial cells contract they force the axial protrusion forward and transform the papilla into a hyperboloidal configuration. The papilla is innervated by small motor fibers, but sensory fibers were not detected. The adhesive papillae of Distaplia are discussed in relationship to nine other recognizable types of papillae in the ascidians.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225658
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Carbon-13-fluorine-19 coupling constants in benzotrifluorides (1977)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 9 (1977), S. 589-592 
    Details
    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
    URL: http://dx.doi.org/10.1002/mrc.1270091008
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Chemical ionization induced fragmentations of 2-phenyl-1,3,2-dioxaborolanes and 2-phenyl-1,3,2-dioxaborinanes (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 196-197 
    Details
    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
    URL: http://dx.doi.org/10.1002/oms.1210140406
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Chemical ionization mass spectrometry: A method of estimating reagent gas pressure in the ion source based on kinetic data (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 507-511 
    Details
    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
    URL: http://dx.doi.org/10.1002/oms.1210140910
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    Paper (German National Licenses)
    Fulltext
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