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  • 1
    ISSN: 1432-1238
    Schlagwort(e): Key words Pulmonary surfactants ; Respiratory distress syndrome ; adult ; N-nitroso-N-methylurethane ; Pulmonary compliance ; Rabbit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Objectives: To define the effect of N-nitroso-N-methylurethane (NNNMU) on pulmonary gas exchange, compliance and the biochemical and functional properties of the lung surfactant system. Design: Four days after inducing lung injury, gas exchange and pulmonary compliance were studied and a bronchoalveolar lavage was taken. Setting: Experimental laboratory of a university department of medicine, division of pulmonary and critical care medicine. Animals: Ten rabbits after they had received an injection of NNNMU and five control animals. Interventions: Controlled mechanical ventilation and bronchoalveolar lavage. Measurements and results: Measurements of gas exchange (using the multiple inert gas elimination technique), hemodynamics and pulmonary compliance were performed during ventilatory and hemodynamic steady state. A bronchoalveolar lavage (BAL) was taken after sacrificing the animal. BAL samples were processed for cell count and biochemical and functional surfactant analysis. Animals injected with NNNMU developed mild, but significant reduction in PaO2, while maintaining eucapnia during spontaneous air breathing. ˙V/˙Q distributions and arterial blood gases were similar in all animals when ventilated mechanically with a fixed tidal volume. Compliance of the lung and phospholipid levels in lavage of NNNMU animals was significantly lower than in control animals (CON). Function of surfactant recovered from animals receiving NNNMU was decreased significantly where compared to CON. Thus, NNNMU resulted in a lowered lavage surfactant phospholipid content, impaired surfactant function, decreased compliance and hypoxemia during spontaneous ventilation. However, gas exchange was similar to that of control animals during mechanical ventilation. Conclusion: We conclude that NNNMU-induced gas exchange abnormalities present after 4 days are mild and are reversed by fixed volume mechanical ventilation despite marked alteration in surfactant function and lung compliance. These observations further define properties of a lung injury model that is of value in the study of surfactant replacement.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1432-1238
    Schlagwort(e): Pulmonary surfactants ; Respiratory distress syndrome, adult ; N-nitroso-N-methylurethane ; Pulmonary compliance ; Rabbit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Objectives To define the effect of N-nitroso-N-methylurethane (NNNMU) on pulmonary gas exchange, compliance and the biochemical and functional properties of the lung surfactant system. Design Four days after inducing lung injury, gas exchange and pulmonary compliance were studied and a bronchoalveolar lavage was taken. Setting Experimental laboratory of a university department of medicine, division of pulmonary and critical care medicine. Animals Ten rabbits after they had received an injection of NNNMU and five control animals. Interventions Controlled mechanical ventilation and bronchoalveolar lavage. Measurements and results Measurements of gas exchange (using the multiple inert gas elimination technique), hemodynamics and pulmonary compliance were performed during ventilatory and hemodynamic steady state. A bronchoalveolar lavage (BAL) was taken after sacrificing the animal. BAL samples were processed for cell count and biochemical and functional surfactant analysis. Animals injected with NNNMU developed mild, but significant reduction in PaO2, while maintaining eucapnia during spontaneous air breathing. $$\dot V/\dot Q$$ distributions and arterial blood gases were similar in all animals when ventilated mechanically with a fixed tidal volume. Compliance of the lung and phospholipid levels in lavage of NNNMU animals was significantly lower than in control animals (CON). Function of surfactant recovered from animals receiving NNNMU was decreased significantly where compared to CON. Thus, NNNMU resulted in a lowered lavage surfactant phospholipid content, impaired surfactant function, decreased compliance and hypoxemia during spontaneous ventilation. However, gas exchange was similar to that of control animals during mechanical ventilation. Conclusion We conclude that NNNMU-induced gas exchange abnormalities present after 4 days are mild and are reversed by fixed volume mechanical ventilation despite marked alteration in surfactant function and lung compliance. These observations further define properties of a lung injury model that is of value in the study of surfactant replacement.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 15 (1994), S. 436-441 
    ISSN: 0272-8397
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: A study of the use of thermoplastic powder coated towpregs in filament winding was conducted. A suitable technique for manufacturing parts with adequate on-line consolidation was identified through an experimental investigation that compared several techniques. This process utilized a single compaction roller on-line consolidation head with hot air guns to obtain consolidation at the lay-down point on the mandrel. The addition of a heated pultrusion die between the creel system and the filament winder was found to produce the best process. Nylon 11/E-glass towpreg was used in this study. The effect of winding speed and compaction force on the quality of the resulting parts was determined in order to optimize the process. Only the speed was found to have a significant effect, with better quality parts being made at higher speed. Observations were also made on parts manufactured with polypropylene and E-glass towpreg, as well as on parts wound with helical patterns.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 4
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: In addition to the predominant dependence on vinylacetate content of the copolymers, temperature shows a significant influence on the high pressure phase equilibrium in the mixtures. That is demonstrated by experimental cloudpoint curves (pressure). In comparison with them coexistence data are calculated for 5 different samples of (ethylene-vinylacetate)-copolymers and the temperature dependence of all model parameters is investigated and correlated.
    Notizen: Nach dem Vinylacetatgehalt der Copolymere übt die Temperatur einen wesentlichen Einfluß auf die Lage des Hochdruckphasengleichgewichtes aus, der durch Trübungsdruckmessungen ermittelt werden kann. In Übereinstimmung damit erfolgen Berechnungen zu Koexistenzdaten für 5 verschiedene Ethylen-Vinylacetat-Copolymere, wobei die Temperaturabhängigkeit aller Modellparameter untersucht und korreliert wird.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Optimizing the equipment for producing high pressure (ethylene-vinylacetate)-copolymers requires data and models for the phase equilibrium conditions at high pressure. Information on the system ethylene + (ethylene-vinylacetate)-copolymer is important for this purpose. Experimental results (cloud-point curves) and model calculations (coexistencecurves) are presented with particular attention to the dependence on vinylacetate content of copolymers.
    Notizen: Die Optimierung des technischen Hochdruckverfahrens zur Herstellung von (Ethylen-Vinylacetat)-Copolymeren erfordert Daten und Modelle des Hochdruckphasengleichgewichtes. Insbesondere interessieren Informationen über das Teilsystem Ethylen + (Ethylen-Vinylacetat)-Copolymere, die aus experimentellen Untersuchungen von Trübungsdruckkurven und aus Ergebnissen von Modellrechnungen zu Koexistenzdaten gewonnen werden. Dabei wird der Abhängigkeit vom Vinylacetatgehalt des Copolymers besondere Aufmerksamkeit geschenkt.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 6
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: In addition to the dependence on temperature and vinylacetate content of the copolymers, the molar mass distribution of the copolymers shows a significant influence on the high pressure phase equilibrium in the mixtures. This is demonstrated by experimental pressure-cloudpoint curves. The coexistence data are calculated with 5 different fractions of a copolymer with 33% vinylacetate content and reflect the experimental results precisely. Model calculations by a classical discontinuous calculation procedure allow the prediction of coexistence curves without additional molar mass-dependence of the model parameters. Further results are provided for the solubilities of the components in the pressure range of 30 to 100 MPa.
    Notizen: Neben der Temperatur und dem Vinylacetatgehalt des Copolymers übt die Molmassenverteilung des Copolymers einen wesentlichen Einfluß auf die Lage des Hochdruckphasengleichgewichtes aus, was durch Trübungsdruckmessungen experimentell gezeigt wird. Die Berechnungen zu Koexistenzdaten für 5 verschiedene Fraktionen eines (Ethylen-Vinylacetat)-Copolymers mit ca. 33% Vinylacetatgehalt spiegeln die experimentellen Verhältnisse wider. Die Modellrechnungen mit einem klassisch diskontinuierlichen Berechnungsverfahren ermöglichen die Vorausberechnung der Koexistenzdaten ohne zusätzliche Molmassenabhängigkeit der Modellparameter. Weiterhin werden Ergebnisse zur gegenseitigen Löslichkeit im Druckbereich von 30 bis 100 MPa mitgeteilt.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: High pressure phase equilibrium calculations are performed with 5 (ethylene-vinylacetate)-copolymers of different vinylacetate content (8 to 42% VA). Miscibility gaps occur in the pressure range from 40 to 140 MPa. Measured pressure cloudpoints of a copolymer are compared with the calculated results. Investigations with inverse gas-liquid-chromatography provide thermodynamic data of the binary system vinylacetate + (ethylene-vinylacetate)-copolymer. The presented results show for the first time a complete picture about the demixing behaviour in this ternary system, where the monomer-mixturelines in the supercritical range. The miscibility gap is predominantly caused by the vinylacetate content of the copolymers. The influence of the distribution of molecular weight is clearly deminished in comparison to the binary system ethylene + (ethylene-vinylacetate)-copolymer.
    Notizen: Berechnungen zum Hochdruckphasengleichgewicht mit fünf (Ethylen-Vinylacetat)-Copolymeren verschiedenen Vinylacetatgehaltes (8 bis 42% VA) werden durchgeführt. Die Mischungslücken im Druckbereich von 40 bis 140 MPa werden angegeben. Einige experimentelle Trübungsdrücke für ein Copolymer werden ermittelt und mit den Berechnungsergebnissen verglichen. Untersuchungen mit inverser Gaschromatographie dienen der Gewinnung thermodynamischer Daten für das binäre Teilsystem Vinylacetat + (Ethylen-Vinylacetat)-Copolymer. Die vorgelegten Ergebnisse liefern erstmalig ein geschlossenes Bild über das Phasenverhalten im ternären System, wobei die Mischung der Monomere überkritisch vorliegt. Der wesentliche Einflußfaktor auf die Entmischung ist durch den Vinylacetatgehalt des Copolymers gegeben. Der Einfluß der Molmassenverteilung wird gegenüber dem Teilsystem Ethylen + (Ethylen-Vinylacetat)-Copolymer deutlich verringert.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 6 (1873), S. 285-286 
    ISSN: 0365-9496
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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