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  • Engineering  (5)
  • GABA  (3)
  • Pitzer model  (3)
  • Cell & Developmental Biology  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Role of γ-aminobutyric acid (GABA) in the extrapyramidal motor system (1971)
    Springer
    Experimental brain research 14 (1971), S. 95-104 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00234913
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  • 2
    Electronic Resource
    Electronic Resource
    Pitzer Parameters for the Pertechnetate Ion in the System Na+/K+/Mg2+/Ca2+/Cl−/SO 2 4 −/TcO − 4 /H2O at 25°C (1998)
    Springer
    Journal of solution chemistry 27 (1998), S. 107-120 
    Details
    ISSN: 1572-8927
    Keywords: Sodium pertechnetate ; magnesium pertechnetate ; potassium pertechnetate ; osmotic coefficients ; activity coefficients ; solubility ; seawater system ; Pitzer model ; binary parameters ; mixing parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Isopiestic vapor pressure experiments are performed at 25°C with aqueous Mg(TcO4)2 solutions and with ternary mixtures containing various combinations of NaTcO4, Mg(TcO4)2, NaCl, MgCl2, Na2SO4, and MgSO4. The osmotic coefficients of the binary solutions are used to evaluate the binary Pitzer parameters β(0), β(1), and CΦ for Mg(TcO4)2. We previously reported these parameters for NaTcO4. The binary parameters for KTcO4 and Ca(TcO4)2 are evaluated from solubilities of KTcO4 in KCl and CaCl2 solutions, respectively. The mixing parameters Θ TcO 4 − /Cl −, ΨM/TcO 4 − /Cl −, Θ TcO 4 − /SO 4 2− , ΨM/TcO 4 − /SO 4 2− , and ΨNa + /Mg 2+ /TcO4 2− are calculated from either osmotic coefficients or solubilities in the corresponding ternary mixtures. The evaluated set of Pitzer parameters predicts well the activity coefficients and solubilities of KTcO4 in multicomponent systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022625605743
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  • 3
    Electronic Resource
    Electronic Resource
    Thermodynamics of Cm(III) in Concentrated Salt Solutions: Carbonate Complexation in NaCl Solution at 25°C (1999)
    Springer
    Journal of solution chemistry 28 (1999), S. 447-462 
    Details
    ISSN: 1572-8927
    Keywords: Trivalent actinides ; curium ; americium ; solution thermodynamics ; carbonate complexation ; ionic strength ; Pitzer model ; concentrated solutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The carbonate complexation reactions of Cm(III) were studied by time-resolved laser fluorescence spectroscopy in 0–6 m NaCl at 25°C. The ionic strength dependence of the stepwise formation constants for the carbonato complexes Cm(CO3) n 3−2n with n = 1, 2, 3, and 4 is described by modeling the activity coefficients of the Cm(III) species with Pitzer's ion-interaction approach. Based on the present results and literature data for Cm(III) and Am (III), the mean carbonate complexation constants at I = 0 are calculated to be: log β 101 o =8.1 ±0.3, log β 102 o =13.0 ± 0.6, log β 103 o =15.2 ± 0.4, and log β 104 o =13.0 ± 0.5. Combining these equilibrium constants at infinite dilution and the evaluated set of Pitzer parameters, a model is obtained, that reliably predicts the thermodynamics of bivalent actinide An(III) carbonate complexation in dilute to concentrated NaCl solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022664013648
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  • 4
    Electronic Resource
    Electronic Resource
    The ion product of H2O, dissociation constants of H2CO3 and pitzer parameters in the system Na+/H+/OH−/HCO 3 − /CO 3 2- /ClO 4 − /H2O at 25°C (1996)
    Springer
    Journal of solution chemistry 25 (1996), S. 327-343 
    Details
    ISSN: 1572-8927
    Keywords: Ion product of water ; carbonic acid ; dissociation constants ; NaClO4 solution ; iomic strength ; activity coefficients ; Pitzer model ; mixing parameters ; solution thermodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The ion product of water and the dissociation constants of carbonic acid have been determined in 0.1, 1.0, 3.0, and 5.0M NaClO4 at 25°C. The ion product of water K w ' has been evaluated by emf measurements with a combined glass electrode in NaClO4 solutions containing 0.001–0.1M HCLO4 or NaOH. The product K H ' K l ' K 2 ' of the Henry constant for CO2 and the dissociation constants for H2CO3 have been determined by titration of carbonate solutions equilibrated with pCO2 =10−3.52 atm, and K 2 ' has been evaluated by potentiometric titration and by measuring the H+ concentration at fixed HCO 3 − and CO 3 2- concentrations. The ion interaction (Pitzer) equations are applied to describe the constants K w ' , K 2 ' and K H ' H 1 ' K 2 ' as a function of the NaClO4 concentration. The experimental data are used to evaluate the mixing parametersΘ i/ClO 4 andΨ i/ClO 4 -/Na+ fori = OH -,HCO 3 - andCO 3 2-
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00972890
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  • 5
    Electronic Resource
    Electronic Resource
    Glutamat- und GABA-Konzentration in Gehirn und Liquor Cerebrospinalis von Ratten unter Behandlung mit Phosphatidylcholin (1982)
    Springer
    European archives of psychiatry and clinical neuroscience 232 (1982), S. 33-38 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00343363
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  • 6
    Electronic Resource
    Electronic Resource
    Einfluß von Aethanol auf die Neurotransmitter Glutamat und GABA (1982)
    Springer
    European archives of psychiatry and clinical neuroscience 232 (1982), S. 183-189 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00343699
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  • 7
    Electronic Resource
    Electronic Resource
    A transient rise in intracellular Ca2+ is a precursor reaction to the zona pellucida-induced acrosome reaction in mouse sperm and is blocked by the induced acrosome reaction inhibitor 3-quinuclidinyl benzilate (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 32 (1992), S. 41-50 
    Details
    ISSN: 1040-452X
    Keywords: Fluo-3 ; Intracellular Ca2+ transient ; QNB ; Population kinetics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The acrosome reaction induced by the zona pellucida in mouse sperm has been shown to proceed in two stages experimentally distinguishable by the fluorescent probe chlortetracycline. Entry into the first stage of sperm bound to isolated, structurally intact zonae pellucidae is blocked by the compound 3-quinuclidinyl benzilate. In this study, we show, utilizing the fluorescent Ca2+ indicator fluo-3, that the first stage of the zona-induced acrosome reaction is characterized by an increase in intracellular Ca2+, followed by a decrease as the acrosome reaction proceeds. This calcium transient is completely suppressed by 3-quinuclidinyl benzilate. We conclude that the Ca2+ transient is induced by the zona pellucida and is required for the zona-induced acrosome reaction. Blockage of this sperm intracellular Ca2+ transient provides a mechanism for the inhibitory action of 3-quinuclidinyl benzilate on the zona-induced acrosome reaction in mouse sperm. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080320108
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  • 8
    Electronic Resource
    Electronic Resource
    A simple and efficient mixed harmonic element for shells of revolution (1997)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 13 (1997), S. 565-572 
    Details
    ISSN: 1069-8299
    Keywords: mixed harmonic element ; shells of revolution ; consistent stress parameters ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A simple and efficient three-noded mixed harmonic axisymmetric element for shells of revolution under non-symmetric loading is developed. The present element considering shear strain is based on a modified mixed variational principle in which the independent unknowns are only the quantities prescribable at the shell edges. The non-symmetric variations of the displacements and stress resultants in the circumferential direction are decomposed in terms of Fourier series. The stress resultants are eliminated on the element level so that the standard stiffness equations are obtained. The importance of consistent stress parameters is addressed and the efficiency of the present consistent mixed element is shown. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    A finite element formulation with stabilization matrix for geometrically non-linear shells (1992)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 33 (1992), S. 1703-1720 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An assumed strain finite element formulation with a stabilization matrix is developed for analysis of geometrically non-linear problems of isotropic and laminated composite shells. The present formulation utilizes the degenerate solid shell concept and assumes an independent strain as well as displacement. The assumed independent strain field is divided into a lower order part and a higher order part. Subsequently, the lower order part is set equal to the displacement-dependent strain evaluated at the lower order integration points and the remaining higher order part leads to a stabilization matrix. The strains and the determinant of the Jacobian matrix are assumed to vary linearly in the thickness direction. This assumption allows analytical integration through thickness, independent of the number of plies. A nine-node element with a judiciously chosen set of higher order assumed strain field is developed. Numerical tests involving isotropic and composite shells undergoing large deflections demonstrate the validity of the present formulation.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620330810
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  • 10
    Electronic Resource
    Electronic Resource
    A SIMPLE AND EFFICIENT MIXED FINITE ELEMENT FOR AXISYMMETRIC SHELL ANALYSIS (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 39 (1996), S. 1903-1914 
    Details
    ISSN: 0029-5981
    Keywords: axisymmetric shell ; mixed finite element ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An efficient, perhaps simplest, three-noded mixed finite element is proposed for axisymmetric shell analysis. The key feature in the present formulation is to start with a better variational principle in which the independent unknowns are only the quantities that can be prescribed at the shell edges. If the consistency for field approximations is satisfied, no other numerical consideration is necessary in the present element. Several examples confirm the satisfactory numerical behaviour of the present mixed element.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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