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  • 1
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The suitability of PVD films of γ-Al2O3 and of ternary Al-O-N as diffusion barriers between a nickel based superalloy CMSX-4 and NiCoCrAlY for a possible application in gas turbines was investigated. Therefore, an Al2O3 film and, alternatively, an Al-O-N film were deposited on CMSX-4 at 100 °C substrate temperature by means of reactive magnetron sputtering ion plating (MSIP). After characterization of composition and structure of the films by X-ray photoelectron spectroscopy (XPS) and grazing incidence X-ray diffraction (XRD), a NiCoCrAlY coating was deposited onto the diffusion barriers and, for comparison, directly onto CMSX-4 by MSIP as well. The composites were annealed for 4 h at 1100 °C under inert atmosphere. Wavelength dispersive X-ray (WDX) element mappings and line-scans of the cross-sectional cut served to evaluate the suitability of the films as diffusion barriers. After detachment of the coatings from the substrate, the phase stabilities of the two metastable phases γ-Al2O3 and Al-O-N were determined by means of grazing incidence XRD. Without a diffusion barrier, enhanced interdiffusion was observed. Analyses of the composite with the γ-Al2O3 interlayer revealed diffusion of Ti and Ta from the substrate into the NiCoCrAlY coating. No interdiffusion of Ni, Ti, Ta, and Cr could be detected in case of the ternary Al-O-N film. Whereas the ternary Al-O-N film remained in the as-deposited X-ray amorphous structure after annealing, a phase change from the γ to the α modification could be observed in case of the Al2O3 film, presumably responsible for its lower efficiency as a diffusion barrier.
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  • 2
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Schlaganfall ; Rehabilitation ; Anschlußheilbehandlung ; Key words Stroke ; Postacute rehabilitation ; Deficit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary A standardized postacute inpatient rehabilitation program (Anschlußheilbehandlung) after stroke is well established in Germany. Yet the needs of patients being admitted to an Anschlußheilbehandlung (AHB) are not completely known. Therefore sociodemographic data, handicap, impairment and neuropsychologic deficits in 200 stroke patients were evaluated before admission to an AHB with different scores (Barthel, modified Rankin Score, NIHSS, HAWIE-R, Wilde, etc.). About half of the patients were still working prestroke. Most patients suffered from several vascular risk factors, which were insufficiently treated, and about a third of the patients had cerebrovascular disease prior to this stroke. At admission to the rehabilitation program the group of patients with severe neurological deficits was small. In average the disability was rather moderate (Rankin=2,6). Mainly gait and finger dexterity were handicapped. Functional impairment was outweighed by neuropsychological deficits.
    Notes: Zusammenfassung Die Anschlußheilbehandlung (AHB) ist ein fester Bestandteil der postakuten Rehabilitation nach einem Schlaganfall. Zwar gibt es genaue Vorgaben zur AHB von Seiten der Kassen- und Rentenversicherungsträger, unklar ist jedoch, welche Patienten in eine AHB eingewiesen werden, welche Störungen sie noch aufweisen und welche Anforderungen sie an eine AHB stellen. Prospektiv wurden 200 Patienten untersucht, die nach einem Schlaganfall an einer AHB teilnahmen. Neben relevanten soziodemographischen und medizinischen Daten wurden verschiedene neurologische (Barthel, modifizierter Rankin Score, NIHSS u.a.) und neuropsychologische (Teile des HAWIE-R, BAT, Wilde u.a.) Meßinstrumente verwendet. Über die Hälfte der Patienten, die in eine AHB nach einem Schlaganfall eingewiesen wurden, stand noch im aktiven Erwerbsleben. Viele Patienten litten unter unzureichend behandelten Risikofaktoren und hatten bereits vaskuläre Vorerkrankungen bevor sie den aktuellen Schlaganfall erlitten. Die neurologischen Störungen waren eher moderat, wohingegen durchschnittlich ganz erhebliche neuropsychologische Leistungseinbußen bestanden.
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  • 3
    ISSN: 0930-9225
    Keywords: Schlüsselwörter Herzchirurgie – multiples Organversagen (MOF) – akutes Atemnotsyndrom des Erwachsenen (ARDS) – Systemic inflammatory response syndrome (SIRS) – Xanthinderivate ; Key words Cardiac surgery – multiple organ failure (MOF) – adult respiratory distress syndrom (ARDS) – systemic inflammatory response syndrome (SIRS) – xanthine derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The potential therapeutic effect of intravenous 3,7-dimethyl-1-(5-oxohexyl)xanthine (Pentoxifylline) in patients at risk for developing multiple organ failure following major cardio-thoracic surgery was assessed. Forty petients having APACHE II score values ≥19 at the first postoperative day after major cardio-thoracic surgery were randomized into two groups to receive either placebo (Control; n=25) or intravenous pentoxifylline (1.5 mg/kg/h) treatment (Pentoxifylline; n=15) as an adjunct to standard supportive therapy. The control group patients as compared to pentoxifylline treated patients required a longer period of time of ventilator support (8.3±3.1 days vs. 3.1±0.9 days; p〈0.05), experienced a higher incidence of renal failure (days on dialysis/hemofiltration: 6.8±3.3 vs 1.2±0.8; p〈0.05) and a longer ICU stay (11.4±3.1 vs. 5.2±1.1 days; p〈0.05). Overall mortality was not different between treatment groups. The results of this first clinical pilot study suggest that supplemental intravenous pentoxifylline treatment may decrease the incidence of acute lung injury and renal failure in patients after cardiac surgery.
    Notes: Zusammenfassung In einer ersten klinischen Pilotstudie wurde die Wirksamkeit einer kontinuierlichen intravenösen Infusion des Xanthinderivates Pentoxifyllin zur Reduktion der Inzidenz des akuten Lungenversagens bei Hochrisiko-Patienten nach großen herzchirurgischen Eingriffen untersucht. Unter 816 konsekutiv operierten Patienten wurden 40 Patienten mit einem hohen Risiko für die Entwicklung eines Multiorganversagens anhand des APACHE II Scores (≥19) am ersten postoperativen Tag identifiziert. Die Patienten wurden in zwei Gruppen randomisiert: Standard-Behandlung (Kontrolle n=25) oder Standard-Behandlung+Pentoxifyllin-Therapie (Pentoxifyllin n=15). Primäre Studienendpunkte waren die Dauer der Beatmungspflichtigkeit, die Inzidenz eines akuten Nierenversagens (Dialyse-/Hämofiltrationspflichtigkeit) und die Verweildauer auf der Intensivstation. Die Ergebnisse von 37 der 40 Patienten konnten ausgewertet werden. Die Pentoxifyllin-Therapie (kontinuierliche intravenöse Infusion von 1,5 mg/kg/h) wurde gut toleriert; es wurden keine anhaltenden signifikanten Nebenwirkungen beobachtet. Die Dauer der Beatmung war signifikant kürzer in der Pentoxifyllin-Gruppe (3,1±0,9 die) als in der Kontrollgruppe (8,3+3,1 die, p=0,037) Im Vergleich zu den mit Pentoxifyllin behandelten Patienten trat bei den Kontroll-Patienten häufiger ein therapiepflichtiges Nierenversagen auf (Dialysetage 6,8±3,3 vs. Pentoxifyllin-Gruppe: 1,2+0,8 die, p=0,048). Die Verweildauer auf der Intensivstation war signifikant kürzer bei den Pentoxifyllin-behandelten Patienten (5,2±1,1 vs. 1,4±3,1 die; p〈0,05). Die Gesamtletalität betrug 36% in der Kontrollgruppe und 33% in der Pentoxifyllin-Gruppe und war nicht signifikant unterschiedlich. Zusammengefaßt konnten wir in dieser ersten klinischen Pilotstudie zeigen, daß eine kontinuierliche Infusion von Pentoxifyllin bei Hochrisiko-Patienten nach großen herzchirurgischen Eingriffen die Inzidenz des akuten Lungen-, und Nierenversagens reduzieren kann.
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  • 4
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Concentrations of chlorophyll a/freshweight (Chl a FW) and photosynthetic pigments/chlorophyll a were studied during one growing season in the current year's (CYN) and last year's needles (LYN) from Norway spruce (Picea abies (L.) Karst.) grown under natural or close-to-natural climate. Climate regimes differed in photosynthetic active radiation (PAR), temperature (T) and UV-B radiation. Pigments were not affected by UV-B but most of the differences between climate regimes, and also seasonal variations within climate regimes, could be related to PAR and T. Generally, two types of response to climate were observed: firstly, pigments reacted primarily to PAR without marked sensitivity to T and exhibited slow response times (〉 30 d), and, secondly, pigments were affected by the combined action of PAR and T and responded faster than 20 d. The Chl a FW and chlorophyll b/chloprophyll a ratio exhibited slow-type response in CYN and fast-type response in LYN. Higher amplitudes in CYN than in LYN were observed for the latter two parameters, which are known to be associated with levels of pigment–protein complexes. It is suggested that slow response in CYN ensures that the high investments in proteins in these needles occur only in response to longer-lasting climate episodes.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 35 (1957), S. 1188-1189 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 35 (1957), S. 195-196 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 94 (1981), S. 1-23 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In this work the mechanism of olefine polymerization with Ziegler-Natta catalysts is presented. The first part is a discussion of the results obtained with soluble catalysts of the (C5H5)2-Ti(IV) type in combination with various aluminiumorganyls. Important analytical results, the characteristics of the yielded polymers and the kinetics of homogeneous and heterogeneous polymerization are discussed. The second part deals with heterogeneous titanium-catalysts, especially so-called carrier-fixed catalysts with Mg-compounds as carrier. The kinetics of ethylene polymerization and the reason for the elevated catalytic activity of such systems is discussed. Finally some mechanisms and their conformity with experimental results are given.
    Notes: In der vorliegenden Arbeit wird der Mechanismus der Olefinpolymerisation mit Ziegler-Natta-Katalysatoren erörtert. Im 1. Teil dieser Arbeit werden Ergebnisse diskutiert, die mit löslichen Katalysatorsystemen auf Basis (C5H5)2Ti(IV)-Verbindungen in Kombination mit verschiedenen Aluminiumorganylen erzielt wurden. Angesprochen werden wichtige analytische Befunde, charakteristische Eigenschaften der erzeugten Polymeren sowie die Kinetik der Polymerisation im homogenen und heterogenen Bereich. Im 2. Teil werden heterogene Katalysatorsysteme auf Titan-Basis behandelt, insbesondere sogenannte trägerfixierte Katalysatoren mit Magnesium-Verbindungen als Trägerkomponente. Hierbei wird insbesondere die Kinetik der Ethylenpolymerisation in den Vordergrund gestellt und die Frage nach dem Grund für die erhöhte Polymerisationsaktivität derartiger Katalysatorsyteme erörtert. Zum Abschluß werden einige Mechanismen im Hinblick auf ihre Übereinstimmung mit experimentellen Befunden diskutiert.
    Additional Material: 8 Ill.
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  • 8
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Untersucht wurde die Molmasse von Polydiallyldimethylammoniumchlorid in Abhängigkeit vom Umsatz der inversen Emulsionspolymerisation. Unter Berücksichtigung von Gel-Effekt und Kettenübertragung auf das Monomere und Polymere wird eine Beziehung vorgeschlagen, mit deren Hilfe die Umsatzabhängigkeit der Molmassen gut beschrieben werden kann. Ferner wurde die ionische Leitfähigkeit des Polyelektrolyten in An- und Abwesenheit von Salzzusätzen gemessen. Mit zunehmender Tetramethylammoniumchlorid-Konzentration läuft die spezifische Leitfähigkeit des Polymeren durch ein Maximum von 2,2 · 10-4 S cm-1 bei Raumtemperatur.
    Notes: The dependence of molecular weight of poly(diallyldimethylammonium chloride) on conversion was studied and a model is proposed for the calculation of the conversion dependence of molecular weight under consideration of gel effect and chain transfer reactions to monomer and polymer. The influence of tetramethylammonium chloride concentration on the ionic conductivity of the solid polymer was studied. A maximum specific ionic conductivity of 2.2 · 10-4 S cm-1 was measured.
    Additional Material: 3 Ill.
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  • 9
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In the present article the kinetics of polymerization of vinyl acetate in suspension up to high conversion was studied. The molecular weight distribution and the side chain branching of polyvinyl acetate produced were examined with respect to micro and macro mixing as well as to reactor type. The following results were achieved: the time-activity curves of the polymerization can be described up to high conversions considering the exponential increase in viscosity of the polymerizing system and combining the viscosity with rate constants of the polymerization. The change of volume of the polymerizing system has no significant influence on kinetics. The narrowest molecular weight distribution of the poly(vinyl acetate) produced was achieved when polymerizing in the homogeneous continuous stirred tank reactor while the broadest molecular weight distribution was observed in the segregated continuous stirred tank reactor. The batch reactor and the flow tube reactor produce polymers with molecular weight distributions lying in between. Considering the side chain branching, another order was found. The batch reactor and the tube reactor show the lowest side chain branching, the homogeneous continuous stirred tank reactor shows a larger one and the segregated continuous stirred tank reactor shows the largest. Possible reasons for the different behavior of the different reactors are discussed. The degree of segregation was determined by experiments.
    Additional Material: 18 Ill.
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  • 10
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The vinyl acetate polymerization system was investigated with respect to the breadth of the molecular weight distribution (MWD) in batch, continuous segregated, and continuous micromixed reactors. Models were developed employing a complex kinetic scheme including polymer transfer and terminal double bond polymerization, without neglecting initiation and termination steps. Inclusion of a gel effect for terminal double bond polymerization gave better agreement with experimental molecular weight data in suspension polymerization. Simulation results showed the MWD order in the three reactor types is not fixed, but a function of reactant concentrations and the importance of chain branching. In some cases changing the initiator type and concentration will change the MWD order.
    Additional Material: 10 Ill.
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