Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles: DFG German National Licenses  (4)
  • Ictaform events  (2)
  • 78.70  (1)
  • Alkali metal chromium chalcogenides  (1)
Source
  • Articles: DFG German National Licenses  (4)
Material
Years
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Effects of methysticin on three different models of seizure like events studied in rat hippocampal and entorhinal cortex slices (1995)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 351 (1995), S. 348-355 
    Details
    ISSN: 1432-1912
    Keywords: High potassium ; Ictaform events ; Low calcium ; Low magnesium ; Methysticin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Methysticin is one of the constituents of Piper methysticum which possesses anticonvulsant and neuroprotective properties. Its effects on different in vitro seizure models were tested using extracellular recordings in rat temporal cortex slices containing the hippocampus and the entorhinal cortex. Elevating [K+]o0 induced seizure-like events with tonic and clonic electrographic phases in area CA1. Lowering [Ca2+]0 caused recurrent seizure like episodes with large negative field potential shifts. Lowering Mg2+ induced short recurrent discharges in area CA3 and CA1 while ictaform events lasting for many seconds were induced in the subiculum, entorhinal and temporal neocortex. In the hippocampus the activity stayed stable over a number of hours. In contrast, the ictaform events in the subiculum, entorhinal and temporal cortex changed their characteristics after one to two hours to late recurrent discharges. In a concentration-range from 10 to 100 μM methysticin reversibly blocked all these types of epileptiform activity. Decreases in [Ca2+]0 and associated slow field potentials evoked by repetitive stimulation of the stratum radiatum or the alveus remained almost unaffected by methysticin. A paired pulse stimulus paradigm used to test for effects of methysticin on synaptically evoked transient field potentials in normal medium revealed interference with mechanisms involved in frequency potentiation. While responses to alvear stimulation were largely unaffected, the responses to a paired pulse stimulus to stratum radiatum were depressed over the whole range of tested stimulus intervals. The findings suggest that methysticin has effects on different patterns of epileptiform activity possibly by interfering with processes responsible for frequency potentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169074
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effects of methysticin on three different models of seizure like events studied in rat hippocampal and entorhinal cortex slices (1995)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 351 (1995), S. 348-355 
    Details
    ISSN: 1432-1912
    Keywords: Key words High potassium ; Ictaform events ; Low calcium ; Low magnesium ; Methysticin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Methysticin is one of the constituents of Piper methysticum which possesses anticonvulsant and neuroprotective properties. Its effects on different in vitro seizure models were tested using extracellular recordings in rat temporal cortex slices containing the hippocampus and the entorhinal cortex. Elevating [K+]0 induced seizure-like events with tonic and clonic electrographic phases in area CA1. Lowering [Ca2+]0 caused recurrent seizure like episodes with large negative field potential shifts. Lowering Mg2+ induced short recurrent discharges in area CA3 and CA1 while ictaform events lasting for many seconds were induced in the subiculum, entorhinal and temporal neocortex. In the hippocampus the activity stayed stable over a number of hours. In contrast, the ictaform events in the subiculum, entorhinal and temporal cortex changed their characteristics after one to two hours to late recurrent discharges. In a concentration-range from 10 to 100 μM methysticin reversibly blocked all these types of epileptiform activity. Decreases in [Ca2+]0 and associated slow field potentials evoked by repetitive stimulation of the stratum radiatum or the alveus remained almost unaffected by methysticin. A paired pulse stimulus paradigm used to test for effects of methysticin on synaptically evoked transient field potentials in normal medium revealed interference with mechanisms involved in frequency potentiation. While responses to alvear stimulation were largely unaffected, the responses to a paired pulse stimulus to stratum radiatum were depressed over the whole range of tested stimulus intervals. The findings suggest that methysticin has effects on different patterns of epileptiform activity possibly by interfering with processes responsible for frequency potentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169074
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The coupling of Cr to Fe studied by circular magnetic X-ray dichroism (1995)
    Springer
    Applied physics 61 (1995), S. 119-122 
    Details
    ISSN: 1432-0630
    Keywords: 78.70 ; 73.40 ; 75.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The coupling of Cr to Fe in stacked Cr/Fe/Cr trilayers is studied by circular magnetic X-ray dichroism using fluorescence yield to monitor the absorption. From the dichroic spectra, we determine the thickness dependent average magnetic coupling of Cr to Fe for Cr layer thicknesses of 1, 2 and 3 ML. We compare our results to new calculated spectra. Additionally, all Cr spectra show significant contributions due to photon scattering processes at theL 2, 3 absorption edges depending on the degree of circular polarization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01538376
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Neue Alkalimetallchromchalkogenide und ihre StruktursystematikProfessor Hartmut Bärnighausen zum 60. Geburtstage gewidmet (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 243-252 
    Details
    ISSN: 0044-2313
    Keywords: Alkali metal chromium chalcogenides ; crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Alkali Metal Chromium Chalcogenides and their Structural ClassificationThe compounds RbCr3S5, K3Cr11S18, RbCr5Se8 and CsCr5Se8 could be obtained in the form of wellshaped crystals via fusion reactions of the alkali metal carbonates with chromium and the corresponding chalcogen. The compounds crystallize in the monoclinic space groups C2/m (RbCr3S5: a = 19.372(3) Å, b = 3.498(1) Å, c = 12.119(2) Å, β = 122.78(1)°, Z = 4; K3Cr11S18: a = 41.876(3) Å, b = 3.463(1) Å, c = 16.315(3) Å, β = 150.07(1)°, Z = 2; RbCr5Se8: a = 18.737(2) Å, b = 3.623(1) Å; c = 9.016(1) Å, β = 104.65(1)°, Z = 2; CsCr5Se8: a = 18.795(2) Å, b = 3.637(1) Å, c = 9.104(1) Å, β = 104.52(1)°, Z = 2).We propose a structure classification from group-subgroup-relations.MAPLE calculations reveal that the reactions of the binary chalcogenides to yield the ternary compounds are exothermic in each case and are dependent on the chromium/alkali metal ratio in the ternary chalcogenides.
    Notes: Durch Umsetzungen der Alkalimetallcarbonate mit Chrom und dem entsprechenden Chalkogen in der Schmelze konnten die Verbindungen RbCr3S5, K3Cr11S18, RbCr5Se8 und CsCr5Se8 als gut ausgebildete Kristalle erhalten werden. Die Verbindungen kristallisieren monoklin im Raumgruppentyp C2/m (RbCr3S5: a = 19,372(3) Å, b = 3,498(1) Å, c = 12,119(2) Å, β = 122,78(1)°, Z = 4; K3Cr11S18: a = 41,876(3) Å, b = 3,463(1) Å, c = 16,315(3) Å, β = 150,07(1)°, Z = 2; RbCr5Se8: a = 18,737(2) Å, b = 3,623(1) Å; c = 9,016(1) Å, β = 104,65(1)°, Z = 2; CsCr5Se8: a = 18,795(2) Å, b = 3,637(1) Å, c = 9,104(1) Å, β = 104,52(1)°, Z = 2).Über Gruppe-Untergruppe-Beziehungen wird eine Struktursystematik vorgeschlagen.MAPLE-Rechnungen zeigen, daß die Reaktionen der binären Chalkogenide zu den ternären Verbindungen jeweils exotherm sind und vom Verhältnis Chrom/Alkalimetall in den ternären Chalkogeniden abhängen.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190205
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...