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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Computing 50 (1993), S. 127-148 
    ISSN: 1436-5057
    Keywords: 65F10 ; 65N20 ; 65N30 ; Anisotropic problems ; block-Gauss-Seidel iteration ; Gauss-Seidel iteration ; hierarchical basis ; multigrid methods ; partial differential equations ; point-oriented methods ; semidefinite system ; sparse grids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zasammenfassung Wir stellen gitterorientierte und neu entwickelte punktorientierte robuste Multilevelverfahren für Voll- und Dünngitterdiskretisierungen vor. Besonders die punktorientierten Multilevelmethoden sind sehr gut zu parallelisieren und erweisen sich als robust für anisotrope Modellprobleme. Sie erlauben eine einfache Erweiterung auf gebietsorientierte Multilevelmethoden mit denselben Eigenschaften. Wir berichten die Ergebnisse numerischer Experimente für die Reduktionszahlen dieser neuen Algorithmen.
    Notes: Abstract We present grid-oriented and newly developed point-oriented robust multilevel methods for full and sparse grid discretizations. Especially the point-oriented multilevel methods are very well suited for parallelization and behave robust for anisotropic model problems. They can be generalized easily to domain-oriented multilevel methods with the same properties.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 91-93 (Jan. 1992), p. 787-792 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 91-93 (Jan. 1992), p. 283-288 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Numerische Mathematik 66 (1993), S. 449-463 
    ISSN: 0945-3245
    Keywords: 65F10 ; 65F35 ; 65N30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary Based on the framework of subspace splitting and the additive Schwarz scheme, we give bounds for the condition number of multilevel preconditioners for sparse grid discretizations of elliptic model problems. For a BXP-like preconditioner we derive an estimate of the optimal orderO(1) and for a HB-like variant we obtain an estimate of the orderO(k 2 ·2 k/2 ), wherek denotes the number of levels employed. Furthermore, we confirm these results by numerically computed condition numbers.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-2072
    Keywords: Cianopramine ; Citalopram ; 5-HT reuptake inhibitors ; Light/dark choice procedure ; Elevated plus-maze test ; Anxiety ; Neophobia ; Acute and chronic treatments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study investigated behavioural effects of very potent 5-HT reuptake inhibitors after acute treatment (cianopramine and citalopram), as well as after chronic treatment (cianopramine), in two behavioural models of anxiety: 1) the light/dark choice procedure in mice and 2) the elevated plus-maze test in rats. In addition, the responses of mice to novelty in a free exploration paradigm were assessed after acute administration of both drugs. A single injection of cianopramine or citalopram increased neophobic reactions in the free exploration test. Furthermore, these drugs increased the avoidance reaction to a brightly illuminated chamber in the light/dark choice procedure as well as to open arms in the elevated plus-maze test. In contrast, after chronic treatment (10 mg/kg IP, once daily for 21 days) of cianopramine, anxiogenic-like effects were no longer produced in the light/dark choice paradigm whereas in the elevated plus-maze test, anxiolytic-like effects appeared. These results shed more light on the 5-HT hypothesis of anxiety, insofar as the increased availability of 5-HT resulting here from reuptake inhibition seems to initially result in an increased emotional reactivity which, however, subsequently disappears during chronic treatment.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2072
    Keywords: Fluprazine ; Eltoprazine ; Serenics ; Exploration ; Locomotion ; Rearing ; Light/dark procedure ; Anxiety ; Emotionality ; Mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two tests designed to elicit responses to novelty and to aversive stimuli were used to study the effects of the serenics fluprazine and eltoprazine on the behaviour of male Swiss mice: a free exploratory test (fluprazine: 2.5, 5 and 10 mg/kg; eltoprazine: 2.5, 5, 10 and 15 mg/kg) and a two-box choice procedure (fluprazine: 1.25, 2.5, 5 and 7.5 mg/kg; eltoprazine: 2.5, 5, 7.5 and 10 mg/kg). Both drugs increased the neophobic reaction, as well as the avoidance of a brightly illuminated box. These effects closely resemble those of psychostimulant drugs such as methamphetamine and caffeine. It is hypothesized that the behavioural changes induced by these drugs may be due to a nonspecific increase of the emotional reactivity of animals.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-2072
    Keywords: CGS 15943A ; DPCPX ; Adenosine antagonists A1 and A2 ; Locomotion ; Anxiety
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract CGS 15943A is the first reported nonxanthine adenosine antagonist and it shows high affinity towards A1 and A2 receptors. The present data show that CGS 15943A increased in a dose-dependent manner locomotor activity of mice confronted with a free exploratory test without markedly modifying rears or, at low or medium doses, novelty seeking responses. In the light/dark choice procedure, which is especially appropriate for revealing anxiolytic and anxiogenic drug-effects, CGS 15943A decreased the time spent by mice in the lit box and increased the number of transitions. By contrast, the highly selective adenosine A1 receptor, DPCPX, did not significantly modify the behavior of mice except at high doses, which decreased it in the free exploratory test. It is suggested that the present findings confirm the hypothesis that the behavioral effects of adenosine antagonists are linked to their actions at adenosine A2 receptors.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1076
    Keywords: Reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase ; Respiratory chain ; Mitochondrial myopathies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We describe eight children with complex I deficiency, four of them with an isolated, the other four with an additional deficiency of complex IV. Clinical, chemical and morphological findings were compared from patients with isolated and combined deficiency. In both groups, the age of onset of symptoms was between the 1st day and the 4th month of life. Clinical and biochemical heterogeneity were observed. We found no correlation between residual activity of complex I in muscle, blood lactate level, and severity of clinical symptoms. Newborns presenting with severe lactic acidosis and children with later onset myopathy were seen in both groups. The group with combined complex I deficiency showed a more severe clinical course. By light microscopy ragged red fibres were only found in two patients with combined deficiency. However, by electron microscopy structural alterations of the mitochondria were observed in six out of seven muscle specimens.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1435-1536
    Keywords: Poly (acrylamide-co-trimethylammoniumethylmethacrylatechloride) ; cationicpolyelectrolytes ; [η]-M relationship ; shearviscosity ; structure-property relationships
    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 cationic copolymerization products of poly (acrylamide-co-trimethylammoniumethylmethacrylate chloride (PTMAC) having cationic monomer percentages of 8%, 25%, and 50% as well as the cationic homopolymer, were characterized with respect to their molecular dimensions. The light-scattering and viscometric measurements were carried out for molecular weights ranging from 200 000 to 12 800 000 g/mol in 1 M NaCl solution at 25°C. It was possible to establish a relationship between the molecular weight and the two parameters: intrinsic viscosity and radius of gyration, for all four polymers. Rheological investigations of the flow properties in 1 M NaCl solution were also carried out using the polymer with a cationic monomer of 50% (PTMAC 50). Structure-property relationships were formulated which made it possible to describe and predict the shear viscosity, both in the zero-shear region (Newtonian region) and in the shear-dependent region (non-Newtonian region) as a function of the polymer concentration, the molecular weight, and shear rate.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 811-821 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly{acrylamide-co-[2-(acryloyloxy)ethyltrimethylammonium chloride]} (1), Poly{acrylamide-co-[2-(methacryloyloxy)ethyltrimethylammonium chloride]} (2) and Poly{acrylamide-co-[3-(acryloylamino)propyltrimethylammonium chloride]} (3) with cationic monomeric unit mole fractions of 8, 25, and 50 mol-%, and the corresponding homopolymers were characterized with respect to their molecular dimensions in 1 M sodium chloride solution at 25°C in the molecular weight range from 200000 to 16000000, using light-scattering and viscometric measurements. It was possible to establish correlations between molecular weight, intrinsic viscosity and radius of gyration. Whereas a steady increase in the exponents of the [η] vs. M- and 〈R2G〉0,5 vs. M-relationships can be observed with increasing charge density, there is an initial decrease in the values of the exponents for 2 and 3, when 8 mol-% of the cationic monomer is inserted into poly-acrylamide. If the charge density is increased further, these values can also be seen to rise steadily. The findings are explained by the different structures in solution, which are formed by the copolymers and homopolymers investigated due to their chemical structure. The radii of gyration were calculated from the intrinsic viscosities with the aid of the Flory-Fox equation. However, neither the results obtained with the Flory-Fox constant Φ0= 3,69. 1024 mol-1, nor those with the value of Φ0= 2,10. 1024 mol-1 showed good agreement with the experimentally recorded data.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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