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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 14 (1971), S. 95-104 
    ISSN: 1432-1106
    Keywords: GABA ; Strio-nigral neurons ; Elongated synaptic vesicles ; Hemitransection ; Bouton-degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Interference with the neuronal connection between the substantia nigra and striatum of rat by hemitransection at the subthalamic level or lesion of left side of striatum by a simple suction method was studied in relation to the concentration of γ-aminobutyric acid (GABA) in both regions. Time interval studies, at two, six, and twelve days after hemitransection, showed that the GABA concentration in substantia nigra had markedly decreased, whereas only a slight change was shown on the striatum of the operated side. Destruction of the striatum by suction caused a significant fall of the GABA content in the ipsilateral side of substantia nigra. However, destruction of the frontal cortex alone did not cause any marked change in the GABA content of the substantia nigra. In addition, electron microscopic studies disclosed that within the synaptic organization of the substantia nigra approximately 20 % of the boutons contained elongated synaptic vesicles, and that, following coagulation of the striatum, some large axosomatic terminals containing elongated synaptic vesicles also underwent degeneration.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 232 (1982), S. 183-189 
    ISSN: 1433-8491
    Keywords: Ethanol ; Barbiturate ; Cortex ; GABA ; Glutamate ; Hippocampus ; Nigra ; Striatum ; Aethanol ; Barbiturat ; Cortex ; GABA ; Glutamat ; Hippocampus ; Nigra ; Striatum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In zwei Versuchsserien wurde der Einfluß von chronischer Aethanolgabe (5 g/kg täglich) über 2 bzw. 4 Wochen auf die Neurotransmitter Glutamat und GABA bei Ratten untersucht. Dabei fand sich ein durch Barbiturat maskierter Anstieg der GABA-Konzentration in Striatum, Hippocampus und Substantia nigra, 8 bzw. 12 Stunden nach der letzten Aethanolgabe. Für Glutamat konnte ebenfalls ein Anstieg in den untersuchten Hirnregionen gefunden werden, der mit den für Dopamin bekannten Veränderungen unter Aethanol vereinbar ist. Die Bedeutung für die Pathogenese hirnorganischer Anfälle und psychotischer Symptome nach chronischem Alkoholmißbrauch wird diskutiert.
    Notes: Summary The effect of chronic ethanol administration, 5 g/kg per day for 2 or 4 weeks, on the neurotransmitters glutamate and GABA was investigated in rats. An increase in GABA was found in the striatum, hippocampus, and substantia nigra, 8 or 12 h after the last ingestion of ethanol, this being masked by injection of barbiturate. In addition an increase of glutamate has been found in the examined brain areas. This is consistent with the known effect of ethanol on brain Dopa metabolism and release. Finally, the relevance of the results for the pathogenesis of withdrawal seizures and delirious states is discussed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 232 (1982), S. 299-304 
    ISSN: 1433-8491
    Keywords: Serum glutamate ; Endogenous depression ; Neurotic depression ; Antidepressants ; Serum-Glutamat ; endogene Depression ; neurotische Depression ; Antidepressiva
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Serum-Glutamatgehalt wurde bei endogen depressiven, neurotisch depressiven, schizophrenen und schizoaffektiven Patienten sowie gesunden Kontrollpersonen bestimmt. Hierbei zeigte sich, daß die Serumglutamatspiegel bei endogen und neurotisch Depressiven signifikant höher waren als bei den anderen Gruppen. Zwischen schizophrenen und schizoaffektiven Patienten sowie Kontrollen zeigten sich dagegen keine signifikanten Unterschiede. Die weitere Analyse der Daten erbrachte die Hypothese, daß die erhöhten Serum-Glutamat-Konzentrationen bei endogen und neurotisch Depressiven eine Folge der antidepressiven Medikation sind. Diese Ergebnisse werden im Hinblick auf die Wirkung der Antidepressiva auf das Serum-Glutamat bei affektiven Störungen diskutiert.
    Notes: Summary Glutamate concentration was determined in serum from endogenous and neurotic depressive patients, in persons with schizophrenia or schizoaffective disorder, and in normal subjects. The mean serum glutamate level in the endogenous and neurotic depressive patients was found to be significantly higher than in any of the other groups. No other statistically significant differences were found. Statistical analysis revealed that the elevated serum glutamate concentration in the endogenous and neurotic depressive patients was probably caused by medication. These results are discussed in view of the effect of antidepressants upon the serum glutamate in the affective disorders.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 232 (1982), S. 33-38 
    ISSN: 1433-8491
    Keywords: Phosphatidylcholine ; Glutamate ; GABA ; Brain ; CSF ; Friedreich's ataxia ; Phosphatidylcholin ; Glutamat ; GABA ; ZNS ; Liquor cerebrospinalis ; Friedreichsche Ataxie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Um zu untersuchen, ob die Gabe von Phosphatidylcholin, die den zentralnervösen Azetylcholingehalt erhöht, einen Einfluß auf die Neurotransmitter Glutamat und GABA hat, wurde 17 von 32 Ratten über 14 Tage 1,5g/kg Lethicon® pro die peroral gegeben. Die fluorometrische Messung der Konzentrationen von Glutamat und GABA in frontalem Cortex, Striatum, Nigra, Kleinhirnrinde sowie von Glutamat im Liquor cerebrospinalis ließ keine signifikanten Unterschiede gegenüber Kontrolltieren erkennen. Nach zweiwöchiger Gabe von Phosphatidylcholin konnte keine zentralnervöse Interaktion des cholinergen Systems mit den Neurotransmittern Glutamat und GABA nachgewiesen werden.
    Notes: Summary Phosphatidylcholine increases CNS concentrations of acetylcholine. In rats we investigated whether or not phosphatidylcholine also influences the neurotransmitters glutamate and GABA. In 17 rats 1.5g/kg Lethicon perorally was administered daily for 2 weeks, 15 rats served as controls. In tissue from frontal cortex, striatum, substantia nigra, cerebellar cortex no significant differences between treated and untreated animals were found in glutamate or GABA concentrations. A central nervous interaction between the cholinergic system and the neurotransmitters glutamate and GABA, therefore, could not be demonstrated after 2 weeks of phosphatidylcholine intake.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 231 (1981), S. 35-39 
    ISSN: 1433-8491
    Keywords: Total tryptophan ; Free tryptophan ; Endogenous depression ; Neurotic depression ; Gesamt- und freies Tryptophan ; Endogene Depression ; Neurotische Depression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Gesamt- und freies Tryptophan wurde im Plasma von 34 endogen Depressiven, 20 neurotisch Depressiven und 25 gesunden Kontrollpersonen bestimmt. Während beim Gesamttryptophan kein Unterschied zwischen den drei Gruppen festgestellt werden konnte, war das freie Tryptophan bei endogen Depressiven und neurotisch Depressiven signifikant erniedrigt. Zwischen endogen und neurotisch Depressiven fand sich kein Unterschied.
    Notes: Summary The levels of total and free tryptophan were determined in the plasma of 34 endogenous depressives, 20 neurotic depressives and 25 healthy volunteers. Whilst the levels of total tryptophan were not different in the three groups, the level of free tryptophan was reduced in both endogenous and neurotic depressives. No difference could be found between endogenous and neurotic depressives.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1252-1257 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 mechanical properties of polyurethane-unsaturated polyester interpenetrating polymer networks (IPNs) that were prepared by reaction injection molding (RIM) process were measured with variations In composition, cross-link density, and relative reaction rate. From dynamic mechanical analysis (DMA), it was found that the two component polymers had a good compatibility over the whole composition range. The tensile strengths of the blends were greater than those of the pure components and had a maximum value at 50/50 composition. The modulus of elasticity and surface hardness decreased and the impact strength increased as the polyurethane content was increased, but the changes were not high at low polyurethane content, below 50%. For higher cross-link density, the compatibility was enhanced and the mechanical properties were improved. When the reaction rates of the components were different, some extent of phase separation was found in DMA and the properties were affected adversely.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    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: Composite reverse osmosis membranes of ionically crosslinked poly(acrylic acid) (PAA) have been prepared. The process consists of coating a porous polysulfone membrane with a thin layer of dilute solution of PAA, drying the thin liquid layer, and ionically crosslinking the PAA in solutions of different salts. The influence of some important preparation parameters on the properties of these membranes was investigated. It was found that all these membranes possessed ion exchange properties and could be ion exchanged; some of them have been found to be suitable for the desalination of low concentration salt solutions. By comparison to cellulose acetate (CA) membranes, higher rejection of phenols may be an interesting property of these membranes.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 4017-4027 
    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 synthesis of sulfonated poly(phenylene oxide) polymer was investigated. The poly(phenylene oxide) was synthesized through oxidative coupling from 2,6-dimethyl-phenol with copper (I) chloride-pyridine catalyst and sulfonated using chlorosulfonic acid. The effects of catalyst concentration, solvent, and other experimental variables on the kinetics of the polymerization of poly(phenylene oxide) and its subsequent sulfonation are reported in detail.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 2117-2131 
    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: Sulfonated polystyrene latex particles were used as acid catalysts in the continuous inversion of sucrose at 50-70°C. The particles (surface charge 168 μeq/g) were confined in a stirred reactor with a semipermeable membrane; sucrose solution was pumped in, and product solution was pumped out. The catalytic activity of the particles was unchanged after 20 days continuous use. Variation of particle size (0.13 and 0.42 μm) and stirring rate showed that internal and external mass transfer was not a controlling factor. The kinetics were pseudo-first-order; the rate constant at 70°C was 2.30/N min as compared with 0.07/N min for macroporous sulfonated ion-exchange resin; the apparent activation energy was 111 kJ/mol as compared with 121 kJ/mol for the homogeneous acid-catalyzed reaction. The faster rate was attributed to the very great surface area, high charge density, and lack of internal diffusional resistance of the latex particles. The proposed mechanism comprised adsorption of sucrose on the particle surface, followed by inversion and desorption of product.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 3187-3199 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Previous attempts to prepare monodisperse styrene/sodium styrene sulfonate copolymer latexes by batch, seeded, and semicontinuous emulsion polymerization were unsuccessful at high concentrations of the functional comonomer. Broad, and sometimes bimodal, size distributions, and large amounts of water soluble homopolymer were obtained. After removal of free monomer, solute and adsorbed homopolymer and copolymer, the overall incorporation of the functional comonomer was found to be low. To overcome these problems, a two stage “shot-growth” or in situ seeding technique was developed. A first stage copolymerization was carried out with a low concentration of sodium styrene sulfonate: the purpose of the functional comonomer was to enhance the stability and regulate the size of the seed particles. When this reaction had reached high conversion (〉 90%), a second stage monomer mixture was added. The ratio of styrene to sodium styrene sulfonate in this mixture determined the final surface charge density. The mechanism by which the NaSS is incorporated in the polymer particles is considered to be by solution copolymerization with solute styrene monomer to form surface active oligoradicals. These radicals adsorb on the particle surface, initiate polymerization and become inextricably bound, preventing their transfer back to the aqueous phase. By this means, it was possible to vary independently the particle size and surface charge density. High concentrations of functional comonomer could be polymerized without undue wastage (incorporations were only slightly less than 100%) or loss of monodispersity. In extreme cases, the area per functional group fell below the theoretical minimum, indicating considerable hydration of the surface layers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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