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  • crystal structure
  • evolution
  • kinetics
  • morphology
  • Springer  (541)
  • 2000-2004  (251)
  • 1985-1989  (290)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Human vitamin C requirements (1987)
    Springer
    European journal of nutrition 26 (1987), S. 125-137 
    Details
    ISSN: 1436-6215
    Keywords: vitamin C ; functions ; kinetics ; pool ; saturation ; requirements ; RDA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Die Bedeutung von Vitamin C für den menschlichen Organismus wird aus den wichtigen Funktionen ersichtlich, an denen das Vitamin beteiligt ist, wie zum Beispiel Kollagen- und Karnitinsynthesen. In neuerer Zeit entdeckt wurde seine Rolle bei der Noradrenalinsynthese, der Inaktivierung von freien Radikalen sowie der Verhinderung der Nitrosaminbildung. Die Vielfalt dieser Vitamin-C-abhängigen Funktionen läßt erkennen, daß die Bedarfsfestsetzung für Vitamin C nicht nur die Verhütung der Mangelkrankheit Skorbut anvisieren, sondern auch berücksichtigen sollte, daß alle diese Funktionen jederzeit genügend Vitamin C zur Verfügung haben müßten, um optimal reagieren zu können. Das Konzept der Gewebesättigung kommt diesem Ziel am nächsten. Studien mit einem kinetischen Modell haben ergeben, daß eine Sättigung mit täglicher Einnahme von 100 mg Vitamin C bei Nichtrauchern und von 140 mg bei Rauchern eintritt, Mengen, die als optimale Werte gelten können. Bei verschiedenen Krankheiten dürfte der Bedarf höher sein; die genauen Mengen müssen jedoch erst noch ermittelt werden.
    Notes: Summary The importance of vitamin C is reflected in its multifunctional roles which include participation in collagen and carnitine syntheses, promotion of iron absorption and the more recently discovered participation in noradrenaline synthesis, inactivation of free radical chain reactions, prevention of N-nitroso compound formation and more. Given the many extra-antiscorbutic functions of the vitamin, the Recommended Dietary Allowances (RDA) should not just prevent deficiency disease but should aim at providing sufficient amounts for all vitamin C-dependent functions to operate at full capacity. The concept of vitamin C tissue saturation is best able to meet this demand. The use of kinetic models has shown that the body pool is saturated with a daily intake of 100 mg vitamin C in non-smokers and 140 mg in smokers, amounts that may be regarded as optimal RDA values. Certain disease states may be accompanied by still higher vitamin C requirements but the exact amounts are not yet known.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02019608
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  • 2
    Electronic Resource
    Electronic Resource
    Die Lage der Vogelsystematik (2000)
    Springer
    Journal of ornithology 141 (2000), S. 263-274 
    Details
    ISSN: 1439-0361
    Keywords: Systematics ; evolution ; anagenesis ; genealogy ; reference system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Verglichen mit anderen Tiergruppen, scheint die artliche Bestandsaufnahme der rezenten Vögel nahezu abgeschlossen zu sein. Doch ist das System der Vögel weiterhin umstritten und mit vielen Neuerungen konfrontiert. Die Gründe dafür liegen hauptsächlich in neuen, vor allem molekularbiologischen Methoden und in den unerwartet reichen Fossilfunden der jüngsten Zeit. Als Beispiele werden Altgaumenvögel, Kranichvögel, Ibisse, Flamingos, Mausvögel, Hopfe und Sperlingsvögel kurz behandelt. Die hier erzielten Fortschritte lassen die Befürchtung Stresemanns, die Großsystematik der Vögel sei mit den vorhandenen Methoden phylogenetisch nicht interpretierbar, zunächst als unbergründet erscheinen. Doch erwachsen einer solchen Interpretation andere Hindernisse, deren Bedeutung bisher zu wenig beachtet wurde, nämlich Parallelentwicklungen, die viel verbreiteter sind als gemeinhin angenommen. Ihre Häufigkeit lässt sich sogar mit evolutionsbiologischen Argumenten begründen. Es ist deshalb nicht zu erwarten, dass die Diskussionen um das „richtige“ System bald verstummen. Um dennoch die Eindeutigkeit der Information in nicht-systematischen Veröffentlichungen zu wahren, wird empfohlen ein etabliertes Referenzsystem auf Zeit zu wählen.
    Notes: Summary Unlike in most animal classes the inventory of extant species of the class Aves seems to be almost complete. Nevertheless avian systematics is challenged by many novelties and seems far from being settled. This is caused mainly by the application of novel methods of molecular analysis to phylogenetic problems and by the unexpectedly rich fossil record collected within the last 10–20 years. Examples from the Palaeognathae, Gruiformes, Threskiornithidae, Phoenicopteridae, Coliiformes, Upupiformes and Passeriformes are briefly treated. The progress in the field seems to disprove Stresemann's pessimistic view that the phylogeny of higher categories (orders) cannot be reconstructed by the available methods. However, phylogenetic interpretations are impeded by obstacles not considered by Stresemann and highly underestimated in most cases, namely by multiple independent developments leading to identical features. Frequent parallel developments are to be expected for theoretical evolutionary reasons. The diagnosis of such homoplasies can be extremely difficult or even impossible. Therefore we cannot expect the discussion about the “best” system of birds to end in the near future. Considering this dynamic situation in systematics, it is recommended to maintain unambiguousness of information in not strictly systematic publications by refering to a well established system as a temporally limited reference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02462236
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  • 3
    Electronic Resource
    Electronic Resource
    On the theory of photoadsorption kinetics of a-Se colloids: The thermal activation energy and compensation effect (1988)
    Springer
    Colloid & polymer science 266 (1988), S. 958-964 
    Details
    ISSN: 1435-1536
    Keywords: a-Se colloids ; photoadsorption ; kinetics ; activation energy ; compensation effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this study, a model is developed to explain in microscopic terms the results obtained from thermally activated photoadsorption experiments in a-Se colloids. The observed compensation effect can be described for two different cases. At low efficiency adsorption, the process is controlled by the potential at the boundary layer. In the high efficiency adsorption case, the process is controlled by diffusion transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410853
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  • 4
    Electronic Resource
    Electronic Resource
    Rate of thermooxidation and polymer morphology (1986)
    Springer
    Colloid & polymer science 264 (1986), S. 1-8 
    Details
    ISSN: 1435-1536
    Keywords: Thermooxidation ; chain scission ; oxygen absorption ; morphology ; isotactic polypropylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstracts A model of the thermooxidation of semicrystalline polymers involving two processes simultaneously is described. The first process is initiated by oxygen dissolved in the interspherulitic amorphous pahse. The second is related to a slower rate of polymer chain scission m the interlamellar amorphous pahse, which is controlled by oxygen diffusion into the spherulite. The presented model describes an exampble of isotactic polypropylene and predicts the effect of polymer morphology on the process of thermooxidation. It leads to the conclusion that the initial rate of polymer chain scission depends on the amount of interspherulitic amorphous phase fraction but the slower rate, considered in steady state conditions of oxygen diffussion into the interlamellar amorphous phase, depends depends on spherulite size according to the derived equation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410302
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  • 5
    Electronic Resource
    Electronic Resource
    Oxygen uptake by isotactic polypropylene of different morphological structure (1986)
    Springer
    Colloid & polymer science 264 (1986), S. 113-116 
    Details
    ISSN: 1435-1536
    Keywords: Isotactic polypropylene ; thermooxidation ; morphology ; oxygen diffusion ; diffusion coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Oxygen uptake by isotactic polypropylene was studied at temperatures below melting point, on samples of various degrees of crystallinity and spherulite size. Diffusion coefficients and activation energy of diffusion were calculated. It is suggested that the dependence of the rate of oxygen uptake on the morphological structure of polymer samples can result from different values of the interspherulitic amorphous phase fraction, which is more easily accessible to oxygen than the interlamellar fraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01414835
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  • 6
    Electronic Resource
    Electronic Resource
    On the morphology of oriented nylon-12 (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 116-119 
    Details
    ISSN: 1435-1536
    Keywords: Electron microscopy ; staining ; morphology ; nylon-12 ; orientation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The morphology of drawn and annealed sheets of nylon-12 was investigated by transmission electron microscopy of stained sections, and the results compared with equivalent small-angle X-ray scattering (SAXS) patterns. A three-component structure was observed, consisting of crystalline (C) and amorphous (A) regions in the microfibrils and an interfibrillar component whose density was deduced to be intermediate between that of the C and A regions. The crystallite width was given satisfactorily by a Guinier analysis of the SAXS profile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412785
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  • 7
    Electronic Resource
    Electronic Resource
    On the physical crosslinking of amine-extended polyurethane urea elastomers: A crystallographic analysis of bis-urea from diphenyl methane-4-isocyanate and 1,4-butane diamine (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 335-341 
    Details
    ISSN: 1435-1536
    Keywords: Polyurethane elastomers ; hard segment ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The substance under investigation is taken as a model for hard segments consisting of MDI 1) and 1,4-butane diamine. It crystallizes in the triclinic space group P¯1 witha=4.6297;b=5.8259;c=25.286 Å;α=90.721;β=91.580;γ=102.90 degrees andZ=1. Bond distances and angles are given, together with some data on the conformation. The most significant finding is that neighbouring molecules in one and the same plane are linked to one another by means of bifurcated hydrogen bonds. A comparison with the corresponding data for an analogous bis-urethane provides a plausible explanation of the main differences between diamine and glycol extension in polyurethane elastomers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412250
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  • 8
    Electronic Resource
    Electronic Resource
    Laser temperature jump experiments with fluorescence polarization and turbidity detection on the phase transition of single shell vesicles of dimyristoylphosphatidylcholine (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 484-493 
    Details
    ISSN: 1435-1536
    Keywords: Phospholipid bilayer ; kinetics ; laser temperature jump ; phase transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The iodine-laser temperature-jump technique has been used to investigate the main phase transition in single shell vesicles of dimyristoylphosphatidylcholine. The probe molecules DPH and TMA-DPH were incorporated into the lipid bilayer and laserT-jump experiments with turbidity and flourescence polarization detection were performed. We found three well separated relaxation processes between 5 μs and 10 ms. The relaxation signals showed strong cooperativity in the relaxation times as well as in their corresponding amplituedes. We attributed the relaxation to the formation and dissolution of clusters of different order inside the bilayer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01458339
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  • 9
    Electronic Resource
    Electronic Resource
    Amphiphilic diacetylenes with pyridine and 2,2′-bipyridine headgroups — polymerization properties in the crystalline state, in LB-multilayers, and in complexes with transition metal salts. Morphology of polymerized multilayers (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 576-586 
    Details
    ISSN: 1435-1536
    Keywords: Solid state polymerization ; diacetylene derivatives ; monomolecular layers ; Langmuir-Blodgett multilayers ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Synthesis, amphiphilic properties and polymerization behaviour of a variety of single and double chain esters of pyridine- and 2,2′-bipyridine-carboxylic acids containing the diacetylene moiety are described. Conversion versus60Co-γ-ray dose curves indicate significant differences in solid-state reactivity of the individual compounds. The esters of isonicotinic acid form polymers that are soluble in chloroform. The monomers can be converted into salt derivatives and transition metal complexes, some of which are characterized concerning their solid state reactivity. Esters of isonicotinic acid form stable monolayers if spread onto neutral or acidified aqueous subphases at temperatures ≤ 15 °C. These monolayers can be deposited on substrates by the Langmuir-Blodgett technique and subsequently be UV-polymerized. In addition, attempts are reported to form polymeric mono- and multilayers by spreading the soluble polymeric amphiphiles at the air-water interface and subsequently transferring the films onto substrates. The two types of polymeric films exhibit morphologies that are significantly different. Polarizing micrographs indicate a domain structure of randomly shaped crystallites of only a few micrometers in diameter for LB-monolayers built up as monomers and polymerized on the substrate. On the other hand, polymer films built up as polymers are inhomogeneous and do not actually represent monomolecular films.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01421891
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  • 10
    Electronic Resource
    Electronic Resource
    Radical desorption in the emulsion polymerisation of vinyl monomers (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 58-64 
    Details
    ISSN: 1435-1536
    Keywords: Polymerisation ; emulsion ; styrene ; methylmethacrylate ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The dependence of emulsion polymerisation rates on a number of important parameters is considered. Attention is paid to the use of seeded emulsion systems for the evaluation of radical desorption coefficients (k o). Experimental conditions are shown to be important. When the average number of radicals per particle is low, large changes in the rate coefficient for chain termination do not have a large effect on the kinetics. With styrene and methylmethacrylate, radical re-absorption by the polymer particles is shown to be important and radical capture efficiences can be high. Consistency is established between the results of a number of workers and values fork o are shown to be lower than those calculated from chain transfer rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422665
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