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  • Ternary metal selenides  (3)
  • Ictaform events  (2)
  • 73.40  (1)
  • Alkali metal chromium chalcogenides  (1)
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Material
Years
Keywords
  • 1
    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
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  • 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
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  • 3
    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
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Darstellung und Kristallstruktur von Rb2Ni3Se4Professor Herbert Jacobs zum 60. Geburtstag gewidmet (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 627-629 
    Details
    ISSN: 0044-2313
    Keywords: Ternary metal selenides ; crystal structure ; MAPLE ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of Rb2Ni3Se4The compound Rb2Ni3Se4 was synthesized by heating a mixture of rubidium carbonate, nickel and selenium at 850°C in an atmosphere of hydrogen. The compound has a golden lustre and crystallizes with the K2Pd3S4-type structure; a = 10.555(3) Å, b = 27.588(6) Å, c = 6.031(6) Å, Z = 8, Fddd (No. 70).The structure can be described as a stacking of layers of the composition Rb2Ni3Se4 with a stacking sequence abcd. The electrostatic part of lattice energy (MAPLE) will be discussed for compounds of the compositions A2M3X4 (A K, Rb, Cs; M Ni, Pd, Pt and X S, Se).
    Notes: Die Darstellung von Rb2Ni3Se4 gelang durch Umsetzung von Rubidiumcarbonat, Nickel und Selen in einem Wasserstoffstrom bei 850°C. Die goldfarbig glänzende Verbindung kristallisiert im K2Pd3S4-Typ; a = 10,555(3) Å, b = 27,588(6) Å, c = 6,031(6) Å, Z = 8, Fddd (Nr. 70).Die Struktur läßt sich als Stapelung von Schichten der Zusammensetzung Rb2Ni3Se4 mit der Stapelfolge abcd beschreiben. Der elektrostatische Anteil der Gitterenergie (MAPLE) wird für Verbindungen des Typs A2M3X4 (mit A K, Rb, Cs; M Ni, Pd, Pt und X S, Se) diskutiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966220409
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  • 5
    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
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  • 6
    Electronic Resource
    Electronic Resource
    K3BiSe3, Rb3BiSe3 und Cs3BiSe3 - Substitutionsvarianten des Th3P4-TypsProfessor Hanskarl Müller-Buschbaum zum 65. Geburtstag gewidmet (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 1003-1005 
    Details
    ISSN: 0044-2313
    Keywords: Ternary metal selenides ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: K3BiSe3, Rb3BiSe3, and Cs3BiSe3 - Derivatives of the Th3P4 Structure TypeThe compounds K3BiSe3, Rb3BiSe3, and Cs3BiSe3 were synthesized by heating mixtures of Bi2O3 and the respective alkalicarbonate in a stream of hydrogen saturated by selenium at 850°C. Thin crystals of the compounds appear red in transmitted light. They crystallize isostructural with Na3AsS3, space group P213, lattice constants a = 9.771(5) Å, a = 10.161(3) Å, and a = 10.587(5) Å for K3BiSe3, Rb3BiSe3, and Cs3BiSe3, respectively. The Na3AsS3 structure type is a derivative of the Th3P4 structure type.
    Notes: Die Darstellung der Verbindungen K3BiSe3, Rb3BiSe3 und Cs3BiSe3 gelang durch Umsetzungen von Bi2O3 mit dem entsprechenden Alkalicarbonat in einem mit Selen beladenen Wasserstoffstrom bei 850°C. Die Verbindungen erscheinen im Durchlicht rot und kristallisieren im Na3AsS3-Typ (Raumgruppe P213) mit den Gitterkonstanten a = 9,771(5) Å für K3BiSe3, a = 10,161(3) Å für Rb3BiSe3 und a = 10,587(5) Å für Cs3BiSe3. Es handelt sich um Substitutionsderivate des Th3P4-Typs.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966220613
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  • 7
    Electronic Resource
    Electronic Resource
    Über Alkaliselenobismutate(III), mit einer Bemerkung zum Th3P4-TypProfessor Rudolf Hoppe zum 75. Geburtstag gewidmet (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1715-1718 
    Details
    ISSN: 0044-2313
    Keywords: Ternary metal selenides ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: About Alkali Seleno Bismuthates (III), with a Comment Regarding the Th3P4 Structure TypeThe synthesis and X-ray single crystal structure determination of the ternary selenides Rb3BiSe3, Cs3BiSe3, and RbK2BiSe3 are described. The compounds were synthesized via a reaction of Bi2O3 with the alkali carbonate in a selencharged hydrogen stream at 850°C. They crystallize in the Na3AsS3 structure type (space group P213). In the discussion of the structure, the aristotypic Th3P4 structure is included.
    Notes: Es wird über die Darstellung und Einkristallstrukturbestimmung der ternären Selenide Rb3BiSe3, Cs3BiSe3 und RbK2BiSe3 berichtet. Die Synthese gelingt durch Umsetzungen von Bi2O3 mit dem entsprechenden Alkalicarbonat in einem mit Selen beladenen Wasserstoffstrom bei 850°C. Die Verbindungen kristallisieren im Na3AsS3-Typ (Raumgruppe P213). In die Strukturdiskussion wird der Th3P4-Typ als Aristotyp mit einbezogen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231107
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