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  • 1
    Electronic Resource
    Electronic Resource
    Apolipoprotein E type 4 allele and Alzheimer's disease: Effect on age at onset and relative risk in different age groups (1996)
    Springer
    Journal of neurology 243 (1996), S. 452-456 
    Details
    ISSN: 1432-1459
    Keywords: Alzheimer's disease ; Apolipoprotein E ; Age at onset ; Relative risk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of the apolipoprotein E (apoE) genotype on the age at onset of Alzheimer's disease (AD) and the relative risk conferred by the apoE ε4 allele were studied in 91 patients and 69 healthy age-matched controls. According to the age of presentation, which varied from 44 to 95 years, subjects were divided into four groups. The inheritance of at least one ɛ4 allele was associated with a significant reduction of the age at onset by 7.7 years among patients who were 83 years or older when examined. A weaker inverse relationship between the ɛ4 allele and the age at onset was also observed among patients who were aged 44–63 years at presentation. The effect of the c4 allele was minimal or absent in the two intermediate age categories. The relative risk of AD conferred by the inheritance of at least one £4 allele showed no consistent age-related pattern. The overall risk expressed as an odds ratio was 5.0 (95% CI 2.4–10.5). With respect to the limitations of the study, we tentatively conclude (1) that the effect of the apoE ɛ4 allele on the age at onset is not restricted to AD patients of a particular age, in accordance with current hypotheses on the role of apoE gene products in the biology of AD; (2) that the relative risk of AD associated with the ɛ4 allele is not significantly modulated by age. Although the apoE ɛ4 allele is an important susceptibility factor for AD occurring in middle age as well as in later life, it is of limited value in routine clinical diagnosis and should not be used for predictive testing in asymptomatic individuals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00900498
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesen und Kristallstrukturen der Polytellurido-Komplexe [K(15-Krone-5)2]2[MTe7] mit M = Zn und Hg (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 500-506 
    Details
    ISSN: 0044-2313
    Keywords: Polytellurido Complexes of Zinc and Mercury ; Synthesis ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structures of the Polyellurido Complexes [K(15-Crown-5)2]2[MTe7] with M = Zn and HgThe title compounds were obtained in the presence of 15-crown 5 from solutions of zinc and mercury acetate, respectively, in DMF by addition of a solution of K2Te3 in DMF at 0°C (M = Zn) and -50°C (M = Hg). They form black crystal needles with metallic luster. Their crystal structures were determined by X-ray diffraction. The structures of [K(15-crown-5)2]2ZnTe7 and [K(15-crown-5)2]2HgTe7 show two-dimensional disorder as evidence by diffuse scattering. The averaged structures that were determined with the Bragg reflexions correspond to space group Pbcn and have very similar lattice parameters. Nevertheless, the structures differ. [HgTe7]2- ions consist of two condensed five membered rings. They are arranged to form strands in the c direction; within of one strand the ions have a definite orientation, but in different strands two different orientations occur randomly. A [ZnTe7]2- ion can be thought of consisting of a Zn2+ ion, a Te42- ion bonded in a chelate manner and a Te32- ion bonded with one terminal Te atom to the Zn2+. The [ZnTe7]2- ions are associated to strands in the c direction with two different strand orientations occuring randomly.
    Notes: Die Titelverbindungen entstehen aus Lösungen der Acetate von Zink bzw. Quecksilber in DMF bei Anwesenheit von 15-Krone-5 nach Zugabe einer Lösung von K2Te3 in DMF bei 0°C (M = Zn) bzw. -50°C (M = Hg). Die Verbindungen bilden schwarze, metallisch glänzende Kristallnadeln, die wir durch röntgenographische Strukturanalysen charakterisiert haben. Die Kristallstrukturen von [K(15-Krone-5)2]2[ZnTe7] und [K(15-Krone-5)2]2[HgTe7] sind zweidimensional fehlgeordnet, wie die entsprechende diffuse Streuung zeigt. Die Überlagerungsstrukturen, die mit Hilfe der Braggschen Reflexe bestimmt wurden, entsprechen bei beiden Verbindungen der Raumgruppe Pbcn bei sehr Ähnlichen Gitterparametern. Trotzdem unterscheiden sich die Strukturen. Die [HgTe7]2--Ionen bestehen aus zwei kondensierten Fünferringen. Sie sind zu Strängen längs c angeordnet, wobei sie innerhalb eines Stranges eine definierte Orientierung haben, aber von Strang zu Strang eine von zwei entgegengesetzten Orientierungen statistisch vorkommt. Ein [ZnTe7]2--Ion kann man sich aufgebaut denken aus einem Zn2+-Ion, einem chelatartig gebundenen Te42--Ion und einem Te32--Ion, das über ein terminales Te-Atom an das Zn2+ gebunden ist. Die [ZnTe7]2--Ionen sind zu Strängen längs c assoziiert, wobei statistisch zwei Strangorientierungen vorkommen.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190311
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  • 3
    Electronic Resource
    Electronic Resource
    Synthese und Kristallstruktur des Nonaselenids [Sr(15-Krone-5)2]Se9 (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 416-420 
    Details
    ISSN: 0044-2313
    Keywords: Nonaselenide ; Synthesis ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of the Nonaselenide [Sr(15-crown-5)2]Se9The title compound was prepared by the reaction of excess selenium with strontium diselenide in DMF in the presence of 15-crown-5. [Sr(15-crown-5)2]Se9 forms black crystals, which are soluble in DMF. They were characterized by FIR spectroscopy and by an X-ray structure determination.Space group P21/n, Z = 4, 2 381 observed unique reflections, R = 0.073. Lattice dimensions at 19°C: a = 1 228.7, b = 1 893.4, c = 1 575.7 pm, β = 99.15°. The compound consists of [Sr(15-crown-5)2]2+ ions in which the strontium ion is coordinated by the oxygen atoms of the crown ether molecules in a sandwich-like fashion, and of Se92- ions with a chain structure, which has a topolocical resemblance with the bicyclic ion Se102-.
    Notes: Die Titelverbindung entsteht durch Einwirkung von überschüssigem Selen auf Strontiumdiselenid in Dimethylformamid (DMF) in Gegenwart von 15-Krone-5. [Sr(15-Krone-5)2]Se9 bildet schwarze, in DMF leicht lösliche Kristalle, die durch das FIR-Spektrum und eine röntgenographische Strukturanalyse charakterisiert werden.Raumgruppe P21/n, Z = 4, 2 381 beobachtete unabhängige Reflexe, R = 0,073. Gitterabmessungen bei 19°C: a = 1 228,7; b = 1 893,4; c = 1 575,7 pm, β = 99,15°. Die Verbindung besteht aus [Sr(15-Krone-5)2]2+-Ionen, in denen das Strontiumion sandwichartig von den O-Atomen der beiden Kronenethermoleküle umgeben ist, und kettenförmigen Se92--Ionen, die topologische Verwandtschaft zu dem bicyclischen Se102--Ion aufweisen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190229
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  • 4
    Electronic Resource
    Electronic Resource
    Synthese und Kristallstrukturen von (PPh4)2[TeS3] · 2 CH3CN und (PPh4)2[Te(S5)2] (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 1046-1050 
    Details
    ISSN: 0044-2313
    Keywords: Trithiotellurate ; Bispentasulfidotellurate(II) ; Preparation ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structures of (PPh4)2[TeS3] · 2 CH3CN and (PPh4)2[Te(S5)2](PPh4)2[TeS3] · 2 CH3CN was obtained by the reaction of PPh4Cl, Na2S4 and Te in acetonitrile. With sulfur it reacts yielding (PPh4)2[Te(S5)2]. The crystal structures of both products were determined by X-ray diffraction. (PPh4)2[TeS3] · 2 CH3CN: triclinic, space group P1, Z = 2, R = 0.041 for 4 629 reflexions; it contains trigonal-pyramidal [TeS3]2- ions with an average Te—S bond length of 233 pm. (PPh3)2[Te(S5)2]: monoclinic, P21/n, Z = 2, R = 0.037 for 2 341 reflexions. In the [Te(S5)2]2- ion the tellurium atom has a nearly square coordination by four S atoms. Along with the Te atoms each of the two S5 groups forms a ring with chair conformation.
    Notes: Bei der Reaktion von PPh4Cl, Na2S4 und Te in Acetonitril entsteht (PPh4)2[TeS3] · 2 CH3CN. Mit Schwefel wurde daraus (PPh4)2[Te(S5)2] erhalten. Von beiden Produkten wurden die Kristallstrukturen mittels Röntgenbeugung bestimmt. (PPh4)2[TeS3] · 2 CH4CN: triklin, Raumgruppe P1, Z = 2, R = 4,1% für 4 629 Reflexe; es enthält trigonal-pyramidale [TeS3]2--Ionen mit einer mittleren Te—S-Bindungslänge von 233 pm. (PPh4)2[Te(S5)2]: monoklin, P21/n, Z = 2, R = 3,7% für 2 341 Reflexe. Im [Te(S5)2]2 -Ion ist das Telluratom annähernd quadratisch von vier S-Atomen koordiniert. Jede der beiden S5-Gruppen bildet zusammen mit dem Te-Atom einen Ring in Sesselkonformation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200617
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