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  • 1
    Electronic Resource
    Electronic Resource
    Involvement of calcium in calcium-current inactivation in smooth muscle cells from rat vas deferens (1987)
    Springer
    The journal of membrane biology 100 (1987), S. 13-19 
    Details
    ISSN: 1432-1424
    Keywords: smooth muscle cells ; Ca channel ; whole cell recording ; inactivation ; Ca dependency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Ca-channel currents were recorded in Cs-loaded single smooth muscle cells from rat vas deferens to define the dependence of the inactivation time course on Ca concentration. The decay of Ca-channel current obtained in a Ba2+- or Sr2+-containing external solution during long voltage-clamp pulses was much slower than that in a Ca-containing solution. The difference was not due to a change in the surface potential of the membrane as judged from the steady-state activation and inactivation curves. When Ca was the charge carrier, increasing external Ca concentration slightly accelerated the rate of inactivation. In addition, the rate of inactivation of Ca-channel current in 10.8mm Ba was also accelerated by adding Ca to the external solution in a concentration-dependent manner. The time course of Ca-current inactivation was slowed when the cells were dialyzed with a high concentration of citrate, a Ca-chelating agent. From these results, we concluded that a mechanism regulated by intracellular Ca activity plays a role in the inactivation of Ca channels in smooth muscle. The Ca-dependent process may protect against Ca overload by regulating Ca entry in smooth muscle cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02209136
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  • 2
    Electronic Resource
    Electronic Resource
    Fast and slowly inactivating components of Ca-channel current and their sensitivities to nicardipine in isolated smooth muscle cells from rat vas deferens (1988)
    Springer
    Pflügers Archiv 411 (1988), S. 289-295 
    Details
    ISSN: 1432-2013
    Keywords: Vas deferens ; Isolated smooth muscle cells ; Whole cell recording ; Ca-channel current ; Inactivation ; Sensitivity to nicardipine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract (1) Fast and slowly inactivating components of Ca-channel current were compared to clarify whether more than one type of Ca-channel exists in smooth muscle cells from rat vas deferens using the whole cell variant of the patch clamp technique. The pipette was filled with 150 mM Cs solution to eliminate outward current and Ba was used as the charge carrier for Ca-channel current. (2) When activated by a 5 s test pulse to 0 mV from a holding potential of −60 mV, the inactivation process of Ba-current was well fitted by the sum of two exponentials. The time constant of the faster inactivating component was 100–300 ms and that of the slower inactivating component was 1.5–3 s. Steadystate inactivation curves of the fast- and slow-components were very similar. (3) The inward current activated at 0 mV from −80 mV was inactivated faster than that from −30 mV. The voltage-dependencies of the peak current from holding potentials of −30 mV and −80 mV were similar. Both had voltage threshold at −30 mV and were maximal at +10 mV. (4) Low concentrations of nicardipine (10−9 to 10−7 M) preferentially inhibited the slow component while higher concentration (10−6 to 10−5 M) were required to block the fast component. The current activated from a holding potential of −30 mV was almost fully suppressed by 10−7 M nicardipine whereas that from −80 mV was blocked only slightly. The voltage dependencies of the peak currents before and during the superfusion with nicardipine (10−7 M) were similar although the peak amplitude was suppressed in the presence of the drug. (5) These results suggest that the existence of either (a) two populations of Ca channels that differ in the time course of inactivation and the sensitivity to nicardipine, but have nearly identical dependence on membrane potential or (b) one population of Ca channel having two different states of inactivation and the sensitivity of nicardipine, in rat vas deferens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00585117
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  • 3
    Electronic Resource
    Electronic Resource
    Characteristics of rectifying devices with thin films of polyphthalocyanine (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2693-2701 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Chemically and thermally stable thin films of polyphthalocyanine were prepared by a simple evaporation-polymerization method. The rectifying characteristics of metal/semiconductor/metal (MSM) type sandwich devices with the film were studied. A Schottky type device metal (Cu, Al, Ti)/polyphthalocyanine/Cu shows reproducible rectifying characteristics when Ti is selected as a counter electrode. The reproducibility is improved by pre-oxidation treatment of the surface of Cu substrate. Best electric parameters for the device are as follows: rectifying ratio = 14; threshold potential difference = 0,61 V; saturation current = 2,5 · 10-6 A · cm-2; barrier height = 0,75 eV; diode ideality parameter = 4,23. Doping of five kinds of quinones [p-benzoquinone (p-BQ), tetrabromo-p-benzoquinone (p-TBBQ) tetrachloro-p-benzoquinone (p-TCBQ) tetrachloro-o-benzoquinone (o-TCBQ) 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)] and 2,5-cyclohexadien-1,4-diylidenedimalodinitrile (TNCR) in thin films of polyphthalocyanine affected electrocharacteristics in some cases. The diode ideality parameter decreases to 2,17 at 0,90 · 10-6 mol · cm-1 of p-TBBQ, and the rectifying ratio increases to about fourteen times by doping p-TBBQ and p-TCBQ. The doped device shows a rectifying response up to 1 kHz.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021901103
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  • 4
    Electronic Resource
    Electronic Resource
    Graft copolymers of poly(ethylene glycol) (PEG) and chitosan (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 18 (1997), S. 547-550 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Graft copolymers of poly(ethylene glycol) (PEG) on a chitosan backbone (PEG-g-chitosan) have been synthesized and their aqueous solution properties were investigated. At pH 6.5 the graft copolymers are 100% soluble, while chitosan phase separates from solution at those conditions. These interesting graft copolymers may be especially suitable as carriers for delivery of anionic drugs, such as proteins, glycosaminoglycans, and DNA plasmids or oligonucleotides.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1997.030180703
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  • 5
    Electronic Resource
    Electronic Resource
    Behaviour of the 1025 cm-1 band of SERS spectra due to pyridine on a silver electrode in aqueous halide media (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 24 (1993), S. 191-197 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The 1025 cm-1 band which occurs in the SERS of pyridine and halide anion was investigated in detail on a silver electrode in neutral and acidic solution. The 1025 cm-1 band was observed to increase in intensity when the silver electrode was treated with the ORC procedure in the presence of pyridine and halide and the concentration of pyridine was then diluted in neutral solution. On the other hand a band began to appear strongly at 1025 cm-1 when the solution was acidified with HCl after the ORC. It was confirmed that the 1025 cm-1 band appearing on dilution in neutral solution has by the same origin as the 1025 cm-1 band which appeared on acidification. The behaviour of the band can be understood if it is assumed that the species giving rise to the 1025 cm-1 band is a silver-pyridine-halide complex generated by the electrode reaction during the ORC.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250240403
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