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  • 1
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract (1) From May to December 1971 at six sites in upstate New York, samples of freshwater Aufwuchs (the largely algal “scum” flora) were collected on sets of exposed microscope slides. Successive standing crop biomass estimates are presented as analyses of total organic carbon (by wet oxidation) and total nitrogen (by micro-Dumas). Nutritional quality of the Aufwuchs can be assessed in carbon to nitrogen (C:N) ratios, and these are correlated with substantive data from concurrent studies on the growth and fecundity of second trophic level snails (Laevapex and Lymnaea). (2) Peak values of carbon biomass for the six sites range from 1.1 mgC/dm2 to 4.2 mgC/dm2, and mean C:N ratios ranged from 3.7:1 to 10.1:1 (corresponding to 29% protein). Higher snail growth rates (computed as increase in mgC/100 snails/30 days) and greater fecundities correlate, beyond certain minimal levels of carbon biomass, to lower C:N ratios in the corresponding Aufwuchs samples. (3) In discussing these nutritional aspects of Aufwuchs production, it is emphasized that freshwater macrophytes have C:N ratios well above 17:1, and are not much fed upon. In smaller bodies of fresh water, the most important sector of primary production is that of the Aufwuchs, and its nutritional quality in terms of lower C:N ratios is of unique significance to the bioenergetics of the second trophic level invertebrates.
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Birth 1 (1974), S. 0 
    ISSN: 1523-536X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1041
    Keywords: Parkinsonism ; treatment ; levodopa ; orphenadrine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In Parkinsonian patients on maximum tolerated doses of levodopa, a double-blind, cross-over trial showed that greater benefit was conferred by additional orphenadrine hydrochloride than by placebo. Further observations suggest that the benefit conferred by supplemental orphenadrine is lost if the drug is withdrawn either suddenly or gradually. The greatest improvements were seen in balance, posture, handwriting, performance of domestic tasks, dressing and feeding.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Semigroup forum 6 (1973), S. 273-281 
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
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  • 5
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Lösung einer linearen homogenen Differentialgleichung (besonders der Schrödinger-Gleichung) durch Entwicklung der Lösungen (Wellenfunktionen) nach einem diskreten vollständigen Satz von Funktionen wird untersucht. Die Entwicklungskoeffizienten sind entweder durch die Variations-Methode (Integral-Methode) oder durch Verallgemeinerung der Methode von Frobenius (Methode ohne Integrale) bestimmbar. Beide Methoden führen zur einer unendlichen Matrix-Eigenwert-Gleichung. Es wird gezeigt, daß die Matrizengleichungen der beiden Verfahren durch die Überlappungsmatrix des Satzes von Basisfunktionen in Beziehung stehen. Es werden die Effekte beschrieben, die sich ergeben, wenn die Matrizen von unendlicher auf endliche Ordnung reduziert werden. Eine Hybridmethode zur Transformation in eine Matrixdarstellung wird vorgeschlagen, die einige Rechenoperationen aus jeder der Originalmethoden anwendet.
    Abstract: Résumé On considère la résolution d'une équation différentielle linéaire homogène (en particulier l'équation Schrödinger) en développant les solutions (fonctions d'ondes) dans un groupe discret complet de fonctions. Les coefficients du développement peuvent être déterminés par la méthode de la variation de Ritz (intégral) ou par une généralisation de la méthode de Frobenius (non-intégral). Chaque méthode mène à une équation infinie matrice eigenvalue. On montre que les équations matrice, intégrales et non-intégrales, sont reliées par la matrice à recouvrement du groupe des fonctions fondamentales. On décrit les effects de tronquer les matrices infinies en ordre limité. On présente une méthode hybride de transformation à une représentation de matrice, qui utilise des techniques de chacune des méthodes originales.
    Notes: Abstract The solution of a linear homogeneous differential equation (in particular the Schrödinger equation) by expansion of the solutions (wave functions) in a discrete complete set of function is considered. The coefficients of the expansion are determinable by either the Ritz variational (integral) method, or by a generalisation of Frobenius's (non-integral) method. Each method leads to an infinite matrix eigenvalue equation. It is shown that the integral and non-integral matrix equations are related by the overlap matrix of the set of basis functions. The effects of truncating the infinite matrices to finite order are described. A hybrid method of transformation to a matrix representation is proposed, which employs some techniques from each of the original methods.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 33 (1974), S. 169-176 
    ISSN: 1432-2234
    Keywords: Two center wave functions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Semi-analytical solutions of the Schrödinger equation for a particle moving in the electrostatic field of two other particles a fixed distance apart, are derived in such a way that the resulting matrix eigenvalue equations contain real symmetric band matrices. Numerical techniques appropriate to the solution of the two simultaneous matrix eigenvalue equations are described; in particular the bisection method is used to determine precisely the significant truncation order of the matrices for a given numerical precision.
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  • 7
    ISSN: 1432-0428
    Keywords: Diabetes ; retinopathy ; platelet adhesiveness ; ADP activated platelet aggregation ; ADP splitting enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'adhésivité des thrombocytes, l'activation par l'ADP de leur agrégation et l'activité des enzymes scindant l'ADP dans le sang et le plasma ont été étudiés chez 22 diabétiques porteurs de rétinopathie grave, chez 22 sujets diabétiques anciens avec une rétinopathie minime ou nulle et chez 28 sujets témoins. On a mesuré le taux d'agrégation des thrombocytes sous l'effet de 5, 3, 2 et 1 μM d'ADP, le maximum d'agrégation atteint et le taux de désagrégation de ces agrégats. Les thrombocytes des sujets atteints de rétinopathie fortement évolutive sont apparus plus sensibles à l'effet de faibles concentrations d'ADP; on a observé un accroissement significatif du degré d'agrégation et une diminution de la vitesse de désagrégation des agrégats thrombocytaires formés dans les conditions expérimentalesin vitro. Si cela se produisaitin vivo, il pourrait en résulter une occlusion des capillaires. Cette sensibilité accrue à l'ADP et cette incapacité à se désagréger n'étaient pas dues à une différence dans l'activité du système d'enzymes scindant l'ADP dans le sang. On n'observe pas de différences significatives dans ces paramètres si l'on compare le groupe important des diabétiques avec les sujets témoins. Contrairement à certains rapports, aucun des deux groupes de diabétiques ne présentait d'accroissement apparent de l'adhésivité des thrombocytes.
    Abstract: Zusammenfassung An 22 Diabetikern mit schwerer Retinopathie, an weiteren 22 Diabetikern mit langem Krankheitsverlauf, aber keiner oder minimaler Retinopathie und an 28 Kontrollpersonen wurde die Adhäsion der Thrombocyten, die Aggregation der durch ADP aktivierten Thrombocyten und die Aktivität von ADP spaltenden Encymen im Blut und Plasma gemessen. Der Grad der Thrombocytenaggregation, ihr Maximum und der Grad der Desaggregation wurden unter dem Einfluß von 5, 3, 2, und 1 μM ADP bestimmt. Die Thrombocyten bei aktiv fortschreitender Retinopathien waren gegenüber der Wirkung von geringen Konzentrationen von ADP empfindlicher. Es wurde auch eine signifikante Erhöhung des Ausmaßes der Aggregation und eine Verminderung des Desaggregationsgrades von Thrombocytenaggregaten, die sich unterin vitro Bedingungen gebildet hatten, festgestellt. Wenn diesin vivo vorkommen sollte, kann daraus ein Verschluß von Kapillaren entstehen. Die erhöhte Empfindlichkeit gegenüber ADP und die Unfähigkeit zur Desaggregation war nicht auf Unterschiede in der Aktivität von ADP spaltenden Enzymen des Blutsystems zurückzuführen. Bei dem Vergleich der großen Gruppe von Diabetikern mit der Kontrollgruppe wurden keine signifikanten Unterschiede der Parameter aufgedeckt. Im Gegensatz zu einigen Berichten in der Literatur konnte bei keiner der Diabetikergruppen eine Erhöhung der Adhäsion von Thrombocyten gefunden werden.
    Notes: Summary Platelet adhesiveness, ADP-activated platelet aggregation and the activity of the ADP-splitting enzymes in blood and plasma have been studied in 22 diabetics with severe retinopathy, 22 long-duration diabetics with minimal or no retinopathy and 28 control subjects. The rate of platelet aggregation under the influence of 5, 3, 2 and 1 μM ADP, the maximum aggregation attained and the rate of disaggregation of these aggregates were measured. The platelets from actively deteriorating retinopaths were found to be more sensitive to the effect of low concentrations of ADP; a significant increase in the extent of aggregation and a decrease in the rate of disaggregation of platelet aggregates formed under the experimental conditions,in vitro were observed. If this should occurin vivo, then capillary occlusion might ensue. This increased sensitivity to ADP and inability to disaggregate, was not due to any differences in the activity of the ADP-splitting enzyme systems in blood. Significant differences in the parameters were not observed when the large diabetic groups were compared with the control subjects. Contrary to some reports, an increase in platelet adhesiveness was not apparent in either diabetic group.
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 22 (1974), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —The conditions required for the optimal activity of several glycosyl transferases were determined in normal and scrapie-affected mouse brain. Particulate preparations were analysed for fucosyl, galactosyl, mannosyl and N-acetyl glucosaminyl transferase activity using endogenous acceptors. Solubilized preparations were analysed for fucosyl, galactosyl and sialyl transferase activity using defined exogenous acceptors. The activity of each of these enzymes was followed at intervals throughout the development of scrapie in the mouse. In the endogenous system no change was found in the fucosyl and mannosyl transferase activities of the scrapie material, but the levels of galactosyl and N-acetyl glucosaminyl transferase began to rise as clinical signs of scrapie developed i.e. at 15–16 weeks post-inoculation. In the exogenous system the levels of galactosyl and fucosyl transferase began to rise in the scrapie material at 11–12 weeks post-inoculation, rising to twice the normal value at 18–20 weeks. Sialyl transferase showed no change in activity.
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 91 (1974), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
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  • 10
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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