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  • Polymer and Materials Science  (17)
  • Engineering  (5)
  • GABA  (3)
  • 27.60+j  (2)
  • 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
    The European physical journal 331 (1988), S. 111-112 
    ISSN: 1434-601X
    Keywords: 21.10.Re ; 23.20.Lv ; 27.60+j
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High spin states of118Xe have been investigated by means of γ ray spectroscopy using the92Mo(29Si,2pn) at a bombarding energy of 110 MeV. Several new side bands as well as the yrast band were established. A band crossing between the ground state and super bands was observed at ħωc = 0.39 MeV. A negative parity band with two quasi particle excitation, and a quasi γ band were also identified.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-601X
    Keywords: 23.20.Lv ; 27.60+j
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High spin states in115Te have been studied using the89Y (29Si, p2n) reaction at a beam energy of 108 MeV.γ-γ coincidence, Eγ, Iγ and excitation functions have been measured. The level scheme has been extended to 82 MeV excitation energy relative to the 11/2 state and several new states are established. The systematical behaviour in odd- N Te isotopes is discussed.
    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 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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  • 6
    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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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2865-2872 
    ISSN: 0887-624X
    Keywords: alkali-soluble random copolymer ; polymeric emulsifier ; aggregate ; hairy ASR layer ; rate of polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An alkali-soluble random copolymer (ASR), poly(styrene/α-methylstyrene/acrylic acid), was used as a polymeric emulsifier in the emulsion polymerization of styrene. The calorimetric technique was applied to study the kinetics of emulsion polymerization of styrene using ASR and a conventional ionic emulsifier, sodium dodecyl benzenesulfonate (SDBS). ASR could form aggregates like micelles, and the solubilization ability of the aggregates was dependent on the neutralization degree of ASR. The rate of polymerization in the ASR system was lower than that in the SDBS system. This result can be explained by the creation of a hairy ASR layer around the particle surface, which decreases the diffusion rate of free radicals through this region. Although a decrease in particle size was observed, the rate of polymerization decreased with increasing ASR concentration. The higher the concentration of ASR is, the thicker and denser ASR layer may be, and the more difficult it would therefore be for radicals to reach the particle through this layer of ASR. The rate of polymerization decreased with increasing the neutralization degree of ASR. The aggregates with high neutralization of ASR are less efficient in solubilizing the monomer and capturing initiator radicals than that of the lower neutralization degree, which leads to decrease in rate of polymerization. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2865-2872, 1998
    Additional Material: 8 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 171-183 
    ISSN: 0887-624X
    Keywords: latex ; sulfonate functional groups ; poly(styrene-sodium styrene sulfonate) ; emulsion copolymerization ; emulsifier-free ; enhanced gel effect ; ion association ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the emulsifier-free emulsion copolymerization of styrene and sodium styrene sulfonate have been examined over a range of comonomer compositions. The rate of polymerization was found to increase dramatically in the presence of small amounts of sodium styrene sulfonate. This increase is attributed to the increased number of particles formed when sodium styrene sulfonate was present and to a gel effect enhanced by ion association. At low concentrations of functional comonomer, where a monodisperse product was obtained, a homogeneous nucleation mechanism of particle generation is proposed. At higher concentrations, broader and then bimodal size distributions were obtained, and this is ascribed to significant aqueous phase polymerization of sodium styrene sulfonate. The water-soluble homopolymer is supposed to act as a locus of polymerization. The occurrence of this aqueous phase side reaction and the generation of secondary particles makes impossible the preparation of highly sulfonated polystyrene latexes by batch or seeded batch emulsion copolymerization.
    Additional Material: 12 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 721-730 
    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: Homo- and copolymerization of ethylene were performed by using a catalyst system composed of TiCl4/THF/MgCl2 complex activated with AlEt3 at 70°C and 3 atm. To investigate the effect of the compositional difference of the catalyst on the rates of homo- and copolymerization and on the reactivity in ethylene-hexene copolymerization, a series of six catalysts with different compositions (Mg/Ti = 0.4-16.5) were prepared by coprecipitation. The catalytic activity in ethylene polymerization increased sharply with the Mg/Ti ratio from 21 (Mg/Ti = 0.4) to 1477 kg PE/g-Ti h (Mg/Ti = 16.5). The activity in copolymerization with 1-hexene also increased with Mg/Ti ratio. The values of r1 were 120, regardless of Mg/Ti ratios within the experimental error range. Enhancement of the polymerization rate by the addition of 1-hexene in the reaction medium was observed only for the catalysts of low Mg/Ti ratio. This unusual effect of 1-hexene on the polymerization rate was explained by chemical and physical processes that occurred during polymerization. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1647-1652 
    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 equilibrium uptake of o-phenyl phenol onto Courtelle S at 98°C was found to follow a Nernst adsorption mechanism, indicating that uptake arises by virtue of hydrophobic interaction as well as ion-dipole, dipole-dipole, and dipole-induced dipole forces operating between the fiber and the nonionic carrier. Differential scanning calorimetry was used to demonstrate the plasticizing action of the carrier on Courtelle S yarn. A linear relationship was obtained between the extent of plasticization, as measured by reduction in Tg of the fiber, and concentration of carrier applied to the fiber with the maximum extent of plasticization, showing a close correspondence to the aqueous solubility of o-phenyl phenol at 98°C, the temperature at which the fiber was treated with the carrier. The relationship between the extent of enhancement of uptake of C. I. Basic Green 4 and C. I. Basic Red 13 onto Courtelle S yarn at 98°C and concentration of the carrier in the dyebath was also examined: The concentration of o-phenyl phenol that gave maximum enhancement of dye uptake coincided with the aqueous solubility of the carrier at 98°C. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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