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  • 2000-2004  (2)
  • 1980-1984  (17)
  • 11
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: The Middle Triassic carbonate buildups of the Dolomites show facies similarities with mud mounds but display apparent architectural elements of flat-topped carbonate platforms. In order to test whether the facies similarities to mounds are also reflected in the internal buildup architecture, a three-dimensional modelling study of the Middle Triassic Monte Cernera buildup has been carried out. The Cernera buildup exhibits apparent geometries suggesting a mounded platform in the lower and uppermost part of the buildup, separated by an interval with apparent platform geometry and a retrogradational platform interior, which is difficult to explain with a flat top platform model. For this purpose, a number of three-dimensional models were constructed using the three-dimensional modelling programme petrelTM. Key geological horizons were constructed based on outcrop measurements, intermediate horizons were calculated in the modelling program, and the intersections of the modelled layers with a digital topography surface were displayed and compared with outcrop photographs. The models were refined stepwise until a best fit with the actual bedding architecture was achieved. The best fit model shows that the mounded geometries in the lower and uppermost part of the buildup are real architectural elements. The intermediate platform stage, about 1·5 km across, had probably retained a mounded top with a relief of up to 50 m, which is difficult to distinguish from an absolutely flat top, but necessary to explain the retrogradational platform interior. The present study shows that Monte Cernera was dominated by mounded geometries at all stages of platform development. The mounded geometry plus facies data suggest that the platform is a deep-water accumulation, below the zone of intense wave energy, but within the photic zone. The Cernera represents a tropical buildup type, which did not have the capacity to grow into continuously wave-swept environments because of the small size and the absence of a wave-resistant energy barrier. Such buildup types are probably common after major crises in earth history, when reef organisms were virtually absent.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Zeitschrift 180 (1982), S. 535-544 
    ISSN: 1432-1823
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Annalen 265 (1983), S. 23-44 
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1573-9686
    Keywords: Arterial blood flow ; Arterial modeling ; Blood flow modeling ; Arterial outflow conditions ; Biofluid dynamics ; Mathematical modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Blood flow in the large systemic arteries is modeled using one-dimensional equations derived from the axisymmetric Navier–Stokes equations for flow in compliant and tapering vessels. The arterial tree is truncated after the first few generations of large arteries with the remaining small arteries and arterioles providing outflow boundary conditions for the large arteries. By modeling the small arteries and arterioles as a structured tree, a semi-analytical approach based on a linearized version of the governing equations can be used to derive an expression for the root impedance of the structured tree in the frequency domain. In the time domain, this provides the proper outflow boundary condition. The structured tree is a binary asymmetric tree in which the radii of the daughter vessels are scaled linearly with the radius of the parent vessel. Blood flow and pressure in the large vessels are computed as functions of time and axial distance within each of the arteries. Comparison between the simulations and magnetic resonance measurements in the ascending aorta and nine peripheral locations in one individual shows excellent agreement between the two. © 2000 Biomedical Engineering Society. PAC00: 8719Uv
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 2066-2072 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphorpentoxid in der Organischen Synthese, VII. - Synthese von 3-Aryl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-iminenDurch Umsetzung von 2-(Acetylamino)-3-pyrrolcarbonitrilen 1 mit einer Mischung von Phosphorpentoxid, N,N-Dimethylcyclohexanamin und einem geeigneten Arylamin-hydrochlorid bei 150-180 °C werden die Titelverbindungen 2 erhalten. Das verwendete Arylamin-hydrochlorid muß absolut wasserfrei sein, da anderenfalls 4-(Arylamino)pyrrolo[2,3-d]pyrimidine 4 als Nebenprodukte entstehen können. - Die Ergebnisse der Prüfung auf Pestizid- und Antikrebs-Wirksamkeit werden mitgeteilt.
    Notes: The title compounds 2 were prepared by treating 2-(acetylamino)-3-pyrrolecarbonitriles 1 with a mixture of phosphorus pentoxide, N,N-dimethylcyclohexanamine, and an appropriate arylamine hydrochloride at 150-180°C. The importance of using absolutely anhydrous arylamine hydrochlorides is stressed because failing this, 4-(arylamino)pyrrolo[2,3-d]pyrimidines 4 can be formed as by-products. - The results from pesticide and anticancer screenings are reported.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1485-1491 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphoramide, XV1).  -  Phosphorpentoxid/Amin-Gemische als Synthesereagenzien für 2-(Dialkylamino)chinolineBei der Umsetzung von Acetaniliden und N,N-Dialkylformamiden mit einer Mischung aus Phosphorpentoxid und einem Dialkylamin bei 250°C wurden 2-(Dialkylamino)chinoline erhalten. Es wird ein HMPT-induzierten Ringschlußreaktionen verwandter Mechanismus vorgeschlagen. Das jeweilige Amin und Formamid müssen aufeinander abgestimmt sein, weil Transacylierungen stattfinden. Die glatteste Reaktion wird beobachtet, wenn das eingesetzte Amin und dasjenige, das aus dem Formamid freigesetzt werden kann, gleich sind, oder wenn das erstere die größere Nucleophilie besitzt. Der Ringschluß kann durch sterische Effekte gehindert werden. Anstelle der Formamide können auch Formate eingesetzt werden.
    Notes: 2-(Dialkylamino)quinolines were prepared by treating acetanilides and N,N-dialkylformamides with a mixture of phosphorus pentoxide and a dialkylamine at 250°C. A mechanism which is related to HMPT induced ring closure reactions is proposed. Proper choice of amine and formamide is important, because transacylation reactions take place. The cleanest reaction was obtained if the amine used and the amine, which could be liberated from the formamide, were identical, or if the former amine has the greater nucleophilicity. Sterical hindrance in the ring closing step may occur. Formates, instead of formamides, can also be used.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1012-1015 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphorus Pentoxide in Organic Synthesis, III1).  -  A New Synthesis of Pyrido[2,3-d]-pyrimidin-4(3H)-onesEthyl 2-acylamino-3-pyridinecarboxylates 1 were reacted with primary amine hydrochlorides, P2O5 and DMCA (N,N-dimethylcyclohexylamine) to yield a series of pyrido[2,3-d]pyrimidine-4(3H)-ones 2. The compounds 1 were prepared by acylating the corresponding ethyl 2-amino-3-pyridinecarboxylates. The new compounds were tested for pesticidal activity.
    Type of Medium: Electronic Resource
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  • 19
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Anellierte 1,2,3-Triazole, I.  -  Synthese von 8-Azapurin-6-onen und 8-Azapurin-6-iminen aus 5-Acetylamino-1,2,3-triazol-4-carbonsäure-ethylesternDie neuen 8-Azapurin-6-one 3 und die entsprechenden 8-Azapurin-6-imine 4 werden durch Cyclokondensation von 5-Acetylamino-1,2,3-triazol-4-carbonsäure-ethylestern 2 mit Amin-hydrochloriden in Gegenwart von Phosphorpentoxid und N,N-Dimethylcyclohexylamin hergestellt. Für die Bildung von 3 und 4 wird ein Reaktionsmechanismus vorgeschlagen. Einige der Produkte 3 wurden auf ihre fungizide Wirksamkeit getestet.
    Notes: The new 8-azapurin-6-ones 3 and the corresponding 8-azapurin-6-imines 4 are prepared by cyclocondensation of ethyl 5-acetylamino-1H-1,2,3-triazole-4-carboxylates 2 with amine hydrochlorides in the presence of phosphorus pentoxide and N,N-dimethylcyclohexylamine. A reaction pathway is proposed for the formation of 3 and 4. Various products 3 have been tested for fungicide activity.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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