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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Zoomorphology 108 (1988), S. 85-91 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The complex, erupting nematocyst batteries of Nanomia cara are described. In addition to the cnidoband, the battery has a central axis containing longitudinal muscles and nerves that run right through to the terminal filament. In addition, an elastic strand lies coiled within the battery. After eruption of the battery, this strand keeps the prey attached to the tentacle. The strand bears hook-like spicules, equipped with barbs that project beyond the surface. Electron microscopy shows that the elastic strand is a mesogloeal structure tunnelled through and through with cellular processes deriving from both ectoderm and endoderm and that the spicules lie in cellular pockets in the interior of the elastic strand. There is nothing in the structure of the spicules or their cellular sheaths to suggest an origin from nematocysts. Energy dispersive X-ray microanalysis shows strong peaks for calcium and for phosphorus in the spicules, indicating that the mineral present in them is an apatite. An organic matrix is also found in the form of fine filaments and a granular axial structure. The spicules are arranged in a linear series along the elastic strand showing progressive increase in size and structural elaboration.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Documenta ophthalmologica 73 (1989), S. 347-357 
    ISSN: 1573-2622
    Keywords: pattern electroretinogram ; Fourier analysis ; fovea ; retinal eccentricity ; spatial tuning ; visual field
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To investigate the value of the extrafoveal pattern electroretinogram for evaluation of local retinal defects, electroretinographic responses to contrast reversal stimulation were recorded at various locations in the central and midperipheral retina. Normal values were established in 20 eyes, and spatial selectivity at different retinal eccentricities was determined in four eyes. The response amplitude was found to decrease steeply from the fovea until about 12° eccentricity and to decline only slowly thereafter. For central stimulation a clear attenuation for coarser patterns was observed. At 20° and at 30° eccentricity the spatial tuning function exhibited a bandpass characteristic, with the maximum amplitude shifting to lower spatial frequencies. Despite the relatively low peripheral amplitudes a satisfactory signal to noise ratio of the second harmonic responses can be obtained by Fourier analysis, which improves clinical applicability. The comparison of sensitivity in the upper and lower retina revealed a considerable asymmetry, with responses in the upper retina approximately 20% higher. No significant difference, however, was found when the temporal or nasal retina was stimulated. The reproducibility of these results is high enough to encourage clinical studies. A case of retinal venous branch occlusion exemplifies the applicability of this technique in eccentric fundus lesions.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of orofacial orthopedics 49 (1988), S. 522-528 
    ISSN: 1615-6714
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Direct bracket-bonding has many advantages since it means improved prophylaxis of caries and of periodontitis. Separation of teeth prior to bonding and the closure of band spaces are no longer necessary. In addition aesthetics is much better compared to conventional bands. However, an important disadvantage of direct bonding appears to be the failure rate. The present study shows that after 38 months merely 93,4% of maxillary brackets and 90,4% of mandibular brackets are still in place. Two thirds of those brackets which were finally lost failed after 15 months. In about 90% of the investigated failures the fracture was observed to be between the bracket metal and the adhesive.
    Abstract: Résumé Les avantages de la technique adhésive pour fixer les brackets sont: Une meilleure prophylaxie de la carie et des parodontopathies, la suppression des séances de séparation nécessaires, la suppression de la fermeture d'un espace restant après la dépose des bagues et une meilleure esthétique en comparaison avec les bagues conventionnelles. Toutefois, un inconvénient important de cette technique est la proportion élevée des échecs. Le présent exposé met en évidence qu'après une période de 38 mois, 93,4% des brackets au maxillaire supérieur et 90,4% des brackets au maxillaire inférieur étaient encore inchangés in situ. 2/3 de tous les brackets enlevés après 38 mois, s'étaient déjà détachés après une période d'environ 15 mois. Dans environ 90% de tous les cas, la rupture s'était produite entre le métal et l'adhésif.
    Notes: Zusammenfassung Vorteile der Bracket-Adhäsivtechnik sind die verbesserte Karies- und Parodontalprophylaxe, nicht mehr notwendige Separiersitzungen, entfallender Restlückenschluß nach der Entbänderung und nicht zuletzt die verbesserte Ästhetik gegenüber konventionellen Bändern. Als wichtiger Nachteil dieser Technik erweist sich aber die erhöhte Mißerfolgsrate. Der vorliegende Beitrag zeigt, daß nach 38 Monaten noch 93,4% der Brackets im Oberkiefer und 90,4% der Brackets im Unterkiefer unverändert in situ sind. Zwei Drittel aller nach 38 Monaten gelösten Brackets hatten sich schon nach etwa 15 Monaten gelöst. In etwa 90% aller Fälle erfolgte der Bruch zwischen Metall und Adhäsiv.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 539 (1986), S. 211-218 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: I.R.-Spectroscopic Investigation of the Interaction between Ni-containing Y-Zeolites and Carbon MonoxideBy the interaction of CO with reduced NiNaY or NiHY samples adsorbed CO on Ni2+ (2 215 cm-1) and on Ni+ (2 085 and 2 095 cm-1, respectively) and two species of adsorbed Ni(CO)4 are formed. Ni(CO)4 is produced in a slow, reversible reaction. Both species are in an equilibrium which is influenced by the acidity of the samples.
    Notes: Bei der Einwirkung von CO auf reduzierte NiNaY- und NiHY- Zeolithe beobachtet man adsorbiertes CO an Ni2+ (2 215 cm-1) und an Ni+ (2 085 bzw. 2 095 cm-1) sowie zwei Formen von adsorbiertem Ni(CO)4. Ni(CO)4 wird in einer langsamen, reversiblen Reaktion gebildet. Die beiden Formen stehen in einem durch die Acidität der Proben beeinflußten Gleichgewicht.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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