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  • 1
    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
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  • 2
    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
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 71 (1999), S. 1036-1036 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 69 (1997), S. 1254-1254 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 1003-1005 
    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
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 239-242 
    ISSN: 0044-2313
    Keywords: Ternary rhenium chalcogenides ; rhenium clusters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cs6Re6Se15, Synthesis, Atomic Arrangement, and the Classification in a System of Structural Design of Ternary Rhenium- and Technetium ChalcogenidesThe ternary selenide Cs6Re6Se15 was prepared via a reaction of caesium carbonate with rhenium in a seleniumcharged hydrogen stream at 850°C. The X-ray single crystal structure determination revealed an atomic arrangement in which, isotypic to the already described compound Cs6Re6S15, [Re6Se8] units are linked by diselenide bridges to a three-dimensional framework corresponding to the scheme {[Re6Se8](Se2)6/2}4-. In this framework six Cs+ ions and one Se2--ion are inserted with respect to the complete formula Cs6Se{[Re6Se8](Se2)6/2}. The classification of this atomic arrangement in a system of structural design of all so far known chalcogenides of rhenium and technetium AxM6Xz with A ≙ alkaline- or alkaline earth metal and X ≙ sulphur or selenium is demonstrated in this paper.
    Notes: Das ternäre Selenid Cs6Re6Se15 wurde durch Umsetzung von Cäsiumcarbonat mit Rhenium in einem mit Selen beladenen Wasserstoffstrom bei 850°C dargestellt. Röntgenographische Einkristallstrukturuntersuchungen führten zu einer Atomanordnung, in der, isotyp zu der bereits beschriebenen Verbindung Cs6Re6S15, [Re6Se8]-Baueinheiten dreidimensional über Diselenbrücken nach dem Schema {[Re6Se8](Se2)6/2}4- zu einer Gerüststruktur verknüpft sind. In diese sind sechs Cs+-Ionen und ein Se2--Ion eingelagert, so daß die vollständige Formel Cs6Se{[Re6Se8](Se2)6/2} lautet. Die Einordnung dieser Atomanordnung in eine Struktursystematik aller bisher bekannten ternären Chalkogenide des Rheniums und Technetiums AxM6Xz mit A ≙ Alkali- oder Erdalkalimetall und X ≙ Schwefel oder Selen wird dargelegt.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 402 (1973), S. 225-231 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Crystal Structure of BaMnS2The compound BaMnS2 can be synthesized by heating an equivalent mixture of BaCO3 and Mn under a current of H2S at 1000°C. The crystal structure was determined by X-ray diffraction techniques. BaMnS2 is orthorhombic, D2h16-Pnma, a = 7.000, b = 4.144, c = 14.00 Å, z = 4. MnS4 tetrahedra linked by corners form waved layers, which are connected by barium ions. BaMnS2 has the same type of structure as the oxide SrZnO2. In the series of tetrahedral structures AxByCz in which A corresponds to an alkali metal or alkaline-earth metal and B to a transition metal, BaMnS2 is the first known example for a sulfide which is isostructural with an oxide.
    Notes: Durch Umsetzung von BaCO3 mit Mn im H2S-Strom bei 1000°C konnte BaMnS2 rein erhalten werden. Die Kristallstruktur wurde über röntgenographische Untersuchungen an Einkristallen aufgeklärt. Raumgruppe: D2h16-Pnma. Elementarzelle: a = 7,000 Å, b = 4,144 Å, c = 14,00 Å, sie enthält 4 Formeleinheiten. Die Manganatome sind tetraedrisch von Schwefelatomen umgeben. Durch Eckenverknüpfungen der Tetraeder werden gewellte Schichten ausgebildet, die über die Bariumatome zusammengehalten werden. BaMnS2 entspricht in seinem Aufbau dem SrZnO2 und ist damit aus der Reihe der Tetraedergerüststrukturen AxByCz, in denen A für ein Alkali- oder Erdalkalimetall und B für ein Nebengruppenmetall stehen, das erste Beispiel für ein Sulfid, das mit einem Oxid isotyp ist.
    Additional Material: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 553 (1987), S. 248-260 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Crystal Chemistry of Some Alkali Thiomanganates and -zincates. With a Remark on the ThCr2Si2-TypeNew quaternary sulfides ALiMS2 (A ≙ K, Rb, Cs and M ≙ Mn, Zn) were synthesized by a reaction of alkali carbonates with manganese and zinc, respectively, in a stream of H2S at 800°C. Single crystal X-ray investigations revealed the structures of KLiMnS2 and KLiZnS2.All compounds are isotypic and crystallize in the BaZn2P2-structure type. The atomic arrangements are treated as nine spheres close packings of sulfur atoms filled with cations. Criteria are given to distinguish the BaZn2P2-structure type from the ThCr2Si2-structure type.
    Notes: Erstmals dargestellt wurden die quaternären Sulfide ALiMS2 (A ≙ K, Rb, Cs und M ≙ Mn, Zn) durch Umsetzung der Alkalicarbonate mit Mangan bzw. Zink im H2S-Strom bei 800°C. Die Strukturen von KLiMnS2 und KLiZnS2 wurden an Einkristallen bestimmt.Alle Verbindungen sind isotyp und kristallisieren im BaZn2P2-Typ. Die Strukturen werden diskutiert als mit Kationen aufgefüllte Neunerkugelpackungen der Schwefelatome. Es werden Kriterien angegeben, die eine Unterscheidung der Strukturtypen BaZn2P2 und ThCr2Si2 erlauben.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cs4Re6S13 and Cs4Re6S13.5  -  Two Compounds with [Re6S8] Clusters Slightly Differing as to their Framework StructuresCs4Re6S13 was synthesized by the reaction of cesium carbonate with rhenium at 800°C in an argon atmosphere charged with sulphur. The preparation of Cs4Re6S13.5 succeeded by an analogous procedure using a stream of H2S.Structural investigations on single crystals revealed atomic arrangements in which [Re6S8] clusters are linked threedimensionally by Sn2- bridges. In the compound Cs4Re6S13 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)4/2 the rhenium atoms of adjacent Re6-octahedra are connected by sulphide and disulphide bridges in a ratio of 1:2. In the compound Cs4Re6S13.5 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)3/2(S3)1/2 one disulphide bridge is replaced by one trisulphide bridge.The nearly regular Re6-octahedra correspond with a diamagnetic 24-electron configuration.
    Notes: Cs4Re6S13 wurde durch Umsetzung von Caesiumcarbonat mit Rhenium in einem mit Schwefel beladenen Argonstrom bei 800°C erhalten. Cs4Re6S13,5 konnte nach einem analogen Verfahren im Schwefelwasserstoffstrom synthetisiert werden.Strukturuntersuchungen an Einkristallen führten zu Atomanordnungen, in denen [Re6S8]-Baueinheiten über Sn2--Brücken dreidimensional zu Gerüststrukturen verknüpft sind. Im Cs4Re6S13 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)4/2 werden die Rheniumatome benachbarter Re6-Oktaeder über Sulfid- und Disulfidbrücken im Verhältnis 1:2 miteinander verbunden, im Cs4Re6S13,5 \documentclass{article}\pagestyle{empty}\begin{document}$\buildrel \wedge \over =$\end{document} Cs4[Re6S8]S2/2(S2)3/2(S3)1/2 ist eine Disulfidbrücke durch eine Trisulfidbrücke ersetzt.Die nahezu regulären Re6-Oktaeder sind in Übereinstimmung mit dem unmagnetischen 24-Valenzelektronenzustand.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 597 (1991), S. 27-32 
    ISSN: 0044-2313
    Keywords: Ternary chalcogenides A2M3X4 (A ≙ alkali metal; M ≙ Ni, Pt, Pd; X ≙ S, Se) crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Layered Structures of Ternary Chalcogenides A2M3X4 (A ≙ K, Rb, Cs; M ≙ Ni, Pd, Pt; X ≙ S, Se)The ternary chalcogenides A2M3X4 have been prepared by fusion reactions of alkali carbonates with metals M ≙ Ni, Pd or Pt and the chalcogens X ≙ S or Se. Alternatively, the chalcogenides could be synthesized from alkali carbonates and M in a stream of hydrogen charged with chalcogen. X-ray investigations on powdered samples and single crystals reveal layered structures in which neutral A2M3X4-slabs from stacking variants.
    Notes: Die Synthese ternärer Chalkogenide A2M3X4 gelang über Schmelzreaktionen durch Umsetzungen von Alkalimetallcarbonaten mit den Metallen M ≙ Ni, Pd oder Pt und den Chalkogenen X ≙ S oder Se oder über eine Reaktion der beiden erstgenannten Komponenten in einem mit Chalkogen beladenen Wasserstoffstrom.Röntgenographische Untersuchungen an pulverförmigen Proben sowie an Einkristallen führten zu Schichtstrukturen, in denen neutrale A2M3X4-Schichtpakete Stapelvarianten erzeugen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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