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  • 1
    Electronic Resource
    Electronic Resource
    Difference in excitability along geometrically inhomogeneous structures and occurrence of “hot spots” (1991)
    Springer
    Biological cybernetics 66 (1991), S. 185-189 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract The differences in excitability along geometrically inhomogeneous, electrically excitable structures as well as the possibility of occurrence of “hot spots” at certain branch points were theoretically analysed on the basis of the Hodgkin-Huxley model assuming uniform specific membrane parameters along the structure length. It was shown that the “hot spots” conditioned by geometrical inhomogeneities should be not only morphological but also functional formations. The excitability at the branch point could be higher than that at the rest of the structure when the branch point was an electrical equivalent of a step decrease in the cable diameter. The stronger the diameter decrease, the higher the excitability at the branch point and thus the higher is the possibility of observation of “hot spots” in the nerve cells whose dendrites have a profuse branching. The realization of the “hot spots”, however, depended on the distance from the site of the stimulus application (synapse) to the branch point and on the stimulus (synaptic current) strength, as well. The closer the synaptic current strength to the threshold value, and the shorter the synapse-branch point distance, the higher was the possibility of a propagating action potential origin at the branch point but not at the site of the stimulus application and thus the higher was the possibility of realization of “hot spots”. The conclusion that the geometrical position of the initial segment contributes to its higher excitability (as compared to the rest of the cell) in the case of orthodromic activation of the neuron was also made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243294
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  • 2
    Electronic Resource
    Electronic Resource
    Decreasing the laser radiation absorption in the plasma plume and improving the sensitivity in quantitative laser microspectral analysis
    Amsterdam : Elsevier
    Spectrochimica Acta Part B: Atomic Spectroscopy 39 (1984), S. 1209-1219 
    Details
    ISSN: 0584-8547
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0584-8547(84)80207-4
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  • 3
    Electronic Resource
    Electronic Resource
    Positional distribution of fatty acids in rabbit lung phospholipids and triacylglycerols and effect of prolonged hyperoxy
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism 450 (1976), S. 1-7 
    Details
    ISSN: 0005-2760
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2760(76)90293-9
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  • 4
    Electronic Resource
    Electronic Resource
    Composition of the low molecular fraction of the Bulgarian viper venom
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/General Subjects 104 (1965), S. 292-295 
    Details
    ISSN: 0304-4165
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0304-4165(65)90250-3
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  • 5
    Electronic Resource
    Electronic Resource
    Sensitivity of 5'-nucleotidase and phospholipase A"2 towards liver plasma membranes modifications
    Amsterdam : Elsevier
    International Journal of Biochemistry 17 (1985), S. 787-792 
    Details
    ISSN: 0020-711X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0020-711X(85)90265-4
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  • 6
    Electronic Resource
    Electronic Resource
    Emission spectral analysis using photographic plates treated with a phenidone developer
    Amsterdam : Elsevier
    Talanta 16 (1969), S. 1583-1587 
    Details
    ISSN: 0039-9140
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0039-9140(69)80220-1
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  • 7
    Electronic Resource
    Electronic Resource
    The influence of secondary passivating SiO"2 films on the parameters of planar bipolar transistors
    Amsterdam : Elsevier
    Thin Solid Films 36 (1976), S. 411-413 
    Details
    ISSN: 0040-6090
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0040-6090(76)90050-X
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  • 8
    Electronic Resource
    Electronic Resource
    Influence of the discharge gas on the emission and thermal characteristics of laser-induced microplasmas (1979)
    Springer
    Microchimica acta 71 (1979), S. 503-514 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Der Einfluß der Schutzgasatmosphäre aus Argon, Sauerstoff oder Argon/Sauerstoff-Mischung in verschiedenen prozentualen Verhältnissen auf die Intensitäten der Spektrallinien, die Menge der verdampften Substanz und die Anregungstemperaturen wurde bei der Verdampfung einer Aluminiumprobe mit Hilfe von Laserstrahlung und mit Nebenanregung des Mikroplasmas untersucht. Ein maximaler Verstärkungseffekt wurde in reinem Argon beobachtet. Das Gasmedium übt keinen Einfluß auf die Menge der verdampften Probensubstanz aus. Im Rahmen der Fehler und der Genauigkeit der angewandten Zweilinienmethode wurden die Anregungstemperaturen von der Art der Gasmischung nicht beeinflußt. Die Laserausrüstung war mit einer Vorrichtung für „Hilfsspannung“ ausgestattet, welche die Verdampfung und Anregung der Probensubstanz in einer Inertgasatmosphäre und in minimalen absoluten Mengen unter Hochenergiebildung in der Entladungsstrecke ermöglichte. Damit konnten die Nachweisgrenzen der Mikroelemente erweitert werden.
    Notes: Summary An investigation has been made of the influence of argon, oxygen, and argon/oxygen blends in various ratios as the protective gas medium, on the intensities of the spectral lines, the amount of substance evaporated, and the excitation temperatures in the evaporation of an aluminium sample with the aid of laser irradiation and subsidiary excitation of the microplasma obtained. Maximum intensifying effect was observed when a pure argon medium was used. The gas medium does not influence the amount of substance evaporated from the sample. Within the experimental error of the twoline method used, the excitation temperatures do not appear to be influenced by the type of gas blend. An auxiliary voltage device was added to the laser equipment, which allows evaporation of the substance in an atmosphere of inert gas and in minute absolute amounts, with high energy in the discharge gap. This new approach improves the limits of detection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01197422
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  • 9
    Electronic Resource
    Electronic Resource
    Power spectra of extracellular potentials generated by an infinite, homogeneous excitable fibre (1990)
    Springer
    Medical & biological engineering & computing 28 (1990), S. 24-30 
    Details
    ISSN: 1741-0444
    Keywords: Extracellular potential ; Intracellular action potential duration ; Mathematical model ; Power spectrum ; Propagation velocity ; Radial distance ; Single fibre
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The power spectra of the extracellular potentials (EPs) generated under activation of an infinite, homogeneous excitable fibre immersed into an infinite, resistive, isotropic and homogeneous volume conductor are theoretically analysed. The changes in the power spectrum related to the changes in the propagation velocity v, amplitudes Vm and duration Tin of the intracellular action potential (IAP) are analytically determined. It is found that in the ultra-low-frequency region the EP spectral power follows the course of alteration in the square of the modified Bessel function of the second kind and order zero multiplied by the fourth power of the frequency, and the Tin can be assessed by the deviation of the EP power spectrum from this function. It is shown why the sensitivity of the spectral characteristics depends substantially on the radial distance y0 from the activated fibre to the point of observation; why the total spectral amplitude depends directly on the IAP wavelength but the total spectral power depends on the IAP wavelength as well as on its duration and propagation velocity; and why the EPs are not proportional to the IAP second spatial derivative even in close proximity to the fibre.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441673
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  • 10
    Electronic Resource
    Electronic Resource
    Power spectra of single infinite fibre extracellular potentials recorded by a bipolar electrode (1990)
    Springer
    Medical & biological engineering & computing 28 (1990), S. 537-543 
    Details
    ISSN: 1741-0444
    Keywords: Bipolar recording ; Extracellular action potential ; Fibre-electrode distance ; Intracellular action potential duration ; Power spectrum ; Propagation velocity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The power spectra of bipolarly recorded extracellular action potentials (EAPs) generated by an infinite, homogeneous, excitable fibre in an infinite, resistive, isotropic and homogeneous volume conductor were theoretically analysed. The changes in the power spectrum of EAP, which occurred as a result of alterations in the propagation velocity v and duration Tin of the intracellular action potential IAP, were analytically determined for bipolar parallel and radial electrodes with a small interpole distance. It was found that the sensitivity of the spectral characteristics to alteration in v, Tin and/or the IAP asymmetry substantially depends on the fibre-electrode distance; information on the IAP fast changes, that seems to be lost in unipolar recording as a result of the filtering effect of the fibre-electrode distance, can be restored. The orientation of the recording electrode need not be taken into account when a qualitative analysis is carried out, but when a quantitative analysis has to be performed, then the electrode orientation has a significant influence. A method is suggested for determination of the fibres' orientation by means of the spectrum of EAPs recorded bipolarly. The selectivity of the bipolar electrodes is analysed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02442604
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