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  • 1
    Electronic Resource
    Electronic Resource
    Die Wirkung von Skorpiongift auf die Ionenströme des Ranvierschen Schnürrings (1968)
    Springer
    Pflügers Archiv 303 (1968), S. 133-149 
    Details
    ISSN: 1432-2013
    Keywords: Node of Ranvier ; Ionic Currents ; Scorpion Venom ; Ranvierscher Schnürring ; Ionenströme ; Skorpiongift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Die Wirkung von Skorpiongift (10−6 g/ml) auf die Ionenströme einzelner markhaltiger Nervenfasern von Xenopus laevis wurde in voltage-clamp-Experimenten untersucht. 2. Skorpiongift beeinflußt sowohl die Natrium- als auch die Kalium-Permeabilität der Schnürringmembran. 3. Die hauptsächlichen Wirkungen des Skorpiongiftes auf die Natrium-PermeabilitätP Na sind: a) Die maximale Natrium-Permeabilität $$\bar P_{_{{\rm N}a} } $$ wird auf 60% ihres an der unvergifteten Membran gemessenen Wertes reduziert. b) Die Natriuminaktivierung wird stark verlangsamt und verläuft in zwei Phasen. c) Der zeitliche Verlauf vonP Na kann unter der Annahme beschrieben werden, daß die Variableh aus zwei Komponentenx undy besteht, deren Zeitkonstanten τ x und τ y 4 bzw. 200 mal so groß sind wie τ h der unvergifteten Membran. 4. Die Wirkungen des Skorpiongiftes auf die Kalium-PermeabilitätP K sind: a) Die maximale Kalium-PermeabilitätP K' wird auf etwa 35% ihres Normalwertes vermindert. b) Der Anstieg vonP K bei Depolarisation wird verlangsamt; zwei Phasen können unterschieden werden. 5. Die Wirkungen auf die Natrium-Inaktivierung und auf die Kalium-Permeabilität können die unter dem Einfluß von Skorpiongift beobachtete extreme Verlängerung des Aktionspotentials erklären.
    Notes: Summary 1. The action of scorpion venom (10−6 g/ml) on the ionic currents of single myelinated nerve fibres of Xenopus laevis was studied in voltage clamp experiments. 2. Scorpion venom was found to affect the sodium permeability as well as the potassium permeability of the nodal membrane. 3. The main effects of scorpion venom on the sodium permeabilityP Na are: a) The maximum sodium permeability $$\bar P_{_{{\rm N}a} } $$ is reduced to 60% of its value in the unpoisoned membrane. b) The sodium inactivation is markedly slowed and proceeds in two phases. c) The time course ofP Na can be described assuming that the variableh is the sum of two componentsx andy, whose time constants τ x and τ y are 4 and 200 times τh of the unpoisoned membrane. 4. The effects of scorpion venom on the potassium permeabilityP K are: a) The maximum potassium permeabilityP K' is reduced to about 35% of its normal value. b) The increase ofP K' upon depolarisation is slowed down; two phases can be distinguished. 5. The effects on sodium inactivation and potassium permeability may explain the extreme prolongation of the action potential under the influence of scorpion venom.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00592631
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  • 2
    Electronic Resource
    Electronic Resource
    Die Wirkung von Skorpiongift auf die Ionenströme des Ranvierschen Schnürrings (1968)
    Springer
    Pflügers Archiv 303 (1968), S. 150-161 
    Details
    ISSN: 1432-2013
    Keywords: Node of Ranvier ; Sodium Inactivation ; Scorpion Venom ; Ranvierscher Schnürring ; Natrium-Inaktivierung ; Skorpiongift
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Die Wirkung von Skorpiongift auf die Inaktivierung der Natrium-PermeabilitätP Na wurde in voltage-clamp-Experimenten an einzelnen markhaltigen Nervenfasern von Xenopus laevis untersucht. 2. Beim normalen Ruhepotential warP Na der vergifteten Membran stärker inaktiviert als an der unvergifteten Membran; bei starken Depolarisationen war die Inaktivierung jedoch unvollständig. 3. Der zeitliche Verlauf vonP Na konnte unter verschiedenen experimentellen Bedingungen mit den Hodgkin-Huxley-Gleichungen beschrieben werden, die wie folgt modifiziert wurden: a) die Variableh wurde durch eine schnelle Komponentex und eine langsame Komponentey ersetzt; b) die Komponentex nahm selbst bei Depolarisationen von mehr als 40 mV nicht auf Null ab.
    Notes: Summary 1. The action of scorpion venom on the inactivation of the sodium permeabilityP Na was studied in voltage-clamp experiments on single myelinated nerve fibres of Xenopus laevis. 2. At the normal resting potentialP Na of the poisoned membrane was more inactivated than the control; at large depolarizations inactivation was, however, incomplete. 3. The time course ofP Na under various experimental conditions could be described by theHodgkin-Huxley equations modified as follows: a) the variableh was split into a fast and a slow component (x andy, respectively); b) componentx did not vanish even for depolarizations by more than 40 mV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00592632
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of calcium ions on the ionic currents of nodes of Ranvier treated with scorpion venom (1972)
    Springer
    Pflügers Archiv 333 (1972), S. 51-61 
    Details
    ISSN: 1432-2013
    Keywords: Node of Ranvier ; Ionic Currents ; Scorpion Venom ; Calcium Ions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Voltage clamp experiments were done on myelinated nerve fibres of Xenopus laevis to study the effect of calcium on the ionic currents of the nodal membrane treated with scorpion venom. Increasing the calcium concentration of the medium from 1.8 to 7.2 mM produced the following changes of the sodium and potassium permeabilities,P Na andP K: a) The incomplete sodium inactivation, which is typical for nodes of Ranvier treated with scorpion venom, is abolished. The curves relatingm ∞ and τ m to membrane potential are shifted by 8–10 mV towards larger depolarizations.P Na and the time constants of the fast and slow components of the sodium inactivation remain practically unchanged. b) The maximum potassium permeability,P K, which is reduced by scorpion venom to 45% of the value observed in the normal node, increases to 68% by addition of calcium ions; τ n is unchanged. These effects of calcium ions on the ionic permeabilities explain the shortening of the extremely prolonged action potential and the inhibition of spontaneous activity observed in nodes of Ranvier poisoned with scorpion venom.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586041
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of Heat Treatment and Additives on the Photochromic and Mechanical Properties of Sol-Gel Derived Photochromic Coatings Containing Spirooxazine (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 923-926 
    Details
    ISSN: 1573-4846
    Keywords: photochromism ; photochromic coatings ; spirooxazine ; photochromic properties ; mechanical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The experimental results on the photochromic and mechanical properties of coatings containing 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-(3H)-naphth(2,1-b)(1,4) oxazine] (SO) derived from 3-glycidyloxypropyltrimethoxysilane (GPTMS), bisphenol A (BPA) and 1-methylimidazole (MI) by sol-gel processing are presented. It is shown that heat treatment temperature is a conflicting factor to the photochromic intensity (Δ A 0), photostability and abrasion resistance of the photochromic coatings. With increasing densification temperature the matrix rigidity increases leading to a decrease of Δ A 0 and at the same time an enhancement of both abrasion resistance and photostability, the optimum heat treatment temperature is 110°C under our experimental conditions. By the use of certain additives, e.g., fluorosilanes (FAS), not only Δ A 0 but also the photostability and the abrasion resistance of the photochromic coatings have been further improved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018384913360
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  • 5
    Electronic Resource
    Electronic Resource
    Enhancement of the Photochromic Performance of Spirooxazine in Sol-Gel Derived Organic-Inorganic Hybrid Matrices by Additives (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 927-929 
    Details
    ISSN: 1573-4846
    Keywords: organic-inorganic hybrids ; sol-gel ; photochromic performance ; spirooxazine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Organic-inorganic hybrid materials synthesized via sol-gel processing are excellent solid matrices for photochromic dyes like spirooxazine, and the photochromic performance can be further enhanced by introducing suitable additives. This work describes the effects of additives on the photochromic intensity (Δ A 0), decolouration rate (k) and photostability of spirooxazine in sol-gel derived organic-inorganic hybrid matrices. They include fluoro-alkylsilane (FAS), bisphenol A (BPA) and methyl-imidazole (MI). FAS enhances both Δ A 0 and photostability, but has little effect on k. The higher the content of BPA, the higher the Δ A 0 and the higher the photostability, but the lower the k. The effect of MI on Δ A 0 and k is not so considerable as that of BPA and is a little complicated, while significant improvement in photostability is achieved by the addition of MI at an optimum concentration with the presence of BPA at a higher content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018337030198
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of heat treatment and additives on the photochromic and mechanical properties of sol-gel derived photochromic coatings containing spirooxazine (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 923-926 
    Details
    ISSN: 1573-4846
    Keywords: photochromism ; photochromic coatings ; spirooxazine ; photochromic properties ; mechanical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The experimental results on the photochromic and mechanical properties of coatings containing 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-(3H)-naphth(2,1-b)(1,4) oxazine] (SO) derived from 3-glycidyl-oxypropyltrimethoxysilane (GPTMS), bisphenolA (BPA) and 1-methylimidazole (MI) by sol-gel processing are presented. It is shown that heat treatment temperature is a conflicting factor to the photochromic intensity (ΔA 0), photostability and abrasion resistance of the photochromic coatings. With increasing densification temperature the matrix rigidity increases leading to a decrease of ΔA 0 and at the same time an enhancement of both abrasion resistance and photostability, the optimum heat treatment temperature is 110°C under our experimental conditions. By the use of certain additives, e.g., fluorosilanes (FAS), not only ΔA 0 but also the photostability and the abrasion resistance of the photochromic coatings have been further improved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02436961
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  • 7
    Electronic Resource
    Electronic Resource
    Enhancement of the photochromic performance of spirooxazine in sol-gel derived organic-inorganic hybrid matrices by additives (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 927-929 
    Details
    ISSN: 1573-4846
    Keywords: organic-inorganic hybrids ; sol-gel ; photochromic performance ; spirooxazine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Organic-inorganic hybrid materials synthesized via sol-gel processing are excellent solid matrices for photochromic dyes like spirooxazine, and the photochromic performance can be further enhanced by introducing suitable additives. This work describes the effects of additives on the photochromic intensity (ΔA 0), decolouration rate (k) and photostability of spirooxazine in sol-gel derived organic-inorganic hybrid matrices. They include fluoroalkylsilane (FAS), bisphenolA (BPA) and methyl-imidazole (MI). FAS enhances both ΔA 0 and photostability, but has little effect onk. The higher the content of BPA, the higher the ΔA 0 and the higher the photostability, but the lower thek. The effect of MI on ΔA 0 andk is not so considerable as that of BPA and is a little complicated, while significant improvement in photostability is achieved by the addition of MI at an optimum concentration with the presence of BPA at a higher content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02436962
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  • 8
    Electronic Resource
    Electronic Resource
    Polymetalates based organic-inorganic nanocomposites (1994)
    Springer
    Journal of sol gel science and technology 3 (1994), S. 189-197 
    Details
    ISSN: 1573-4846
    Keywords: nanocomposites ; sol-gel ; heteropolymetalates ; photochromics ; electrochemical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract New nanocomposites materials have been synthesized. They present electrochemical and photochromic properties. They are based on a hybrid organic-inorganic network, in which tungsten heteropolyoxometalates (PW12O 40 3− , SiW12O 40 4− , W10O 32 4− , polymeric tungstate) are entrapped. High tungsten ratios could be reached and films or bulk materials have been obtained. The structure of these materials is described on the basis of multi-spectroscopic investigations (IR, EPR, NMR). Electrochemical redox reactions have been observed in thin films. Dark blue reversible coloration of the materials is obtained under UV irradiation. The photochromic mechanism has been investigated and shows the reversible formation of carbonyl group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00486557
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  • 9
    Electronic Resource
    Electronic Resource
    Photochromic Organic-Inorganic Nanocomposites as Holographic Storage Media (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 7 (1997), S. 123-133 
    Details
    ISSN: 1057-9257
    Keywords: nanocomposites ; sol-gel ; heteropolymetallates ; photochromics ; holographic data storage ; amplitude grating ; two-wave-mixing recording ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: This paper describes the properties of some new organic-inorganic photochromic layers. They are based on a hybrid organic-inorganic matrix in which tungsten heteropolyoxometallates (SiW12O4-40, PW12O3-40) are entrapped in a network obtained from the reaction of 3-glycidoxy-propyltrimethoxysilane. The high homogeneity of these materials on the nanoscale leads to transparent monoliths and layers of controlled thicknesses up to 40 μm. The optical properties of the blend are emphasised and the construction of amplitude gratings in the materials by two-wave-mixing experiments is described. The results of the optical experiments and the comparison with the theoretical background are used as a model for photochromic holographic storage processes. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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