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  • 1
    ISSN: 0197-8462
    Keywords: cellular phone ; sleep EEG ; REM sleep ; spectral power density ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: To investigate the influence of radiofrequency electromagnetic fields (EMFs) of cellular phone GSM signals on human sleep electroencephalographic (EEG) pattern, all-night polysomnographies of 24 healthy male subjects were recorded, both with and without exposure to a circular polarized EMF (900 MHz, pulsed with a frequency of 217 Hz, pulse width 577 μs, power flux density 0.2 W/m2. Suppression of rapid eye movement (REM) sleep as well as a sleep-inducing effect under field exposure did not reach statistical significance, so that previous results indicating alterations of these sleep parameters could not be replicated. Spectral power analysis also did not reveal any alterations of the EEG rhythms during EMF exposure. The failure to confirm our previous results might be due to dose-dependent effects of the EMF on the human sleep profile. Bioelectromagnetics 19:199-202, 1998. © 1998 Wiley-Liss, Inc.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 40 (1989), S. 430-435 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The polymerization of 1,3-dioxepane (DE) in presence of poly(ethylene glycol) (M̄n = 600 g/mol, PEG 600) initiated by perchloric acid proceeds with a transfer reaction to the OH-groups of the glycol. Block copolymers are formed. DE homopolymers and block copolymers with more than one PEG unit per molecule are built by splitting and reconnecting reactions at the acetalic oxygen atoms initiated by protons. By these exchange reactions the statistical most probable average structure is obtained.
    Notes: Die HClO4-initiierte Polymerisation von 1,3-Dioxepan (DE) in Gegenwart von Poly(ethylenglycol) (M̄n = 600 g/mol, PEG 600) verläuft unter Übertragung auf die OH-Gruppen des Poly(ethylenglycols). Es werden Blockcopolymere gebildet. Durch protoneninitiierte Spaltungs- und Neuverknüpfungsreaktionen an den acetalischen Sauerstoffatomen kommt es zur Bildung von DE-Homopolymeren und Blockcopolymeren mit mehr als einer PEG 600-Struktureinheit im Molekül. Diese Austauschreaktionen führen dazu, daß sich letztlich die als statistisch am wahrscheinlichsten anzusehende mittlere Struktur herausbildet.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 514 (1984), S. 72-78 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [PPh3Cl]⊕[ReCl4(N2S2)]⊖; Synthese, IR-Spektrum und Kristall StruktureThe title compound is prepared by the reaction of [ReCl3(NSCl)2(POCl3)] with triphenylphosphane; it formes black crystals. The crystal structure determination was solved with X-ray methods (2861 observed independent reflexions, R = 0.038). The compound crystallizes monoclinic in the space group P21/n with four formula units per unit cell. The structure consists of [PPh3Cl]⊕ cations and [ReCl4(N2S2)]⊖ anions, in which the rhenium atom is surrounded octahedrally by four chlorine ligands and the N atoms of a ReN2S2-five-membered ring in cis-position (symmetry C2v). The Re—N bond lengths (181 pm) and the NS bond lengths (152 pm) are in the range of double bonds; the S—S distance is very long (253 pm). The i.r. spectrum is reported.
    Notes: Die Titelverbindung entsteht in Form schwarzer Kristalle bei der Reaktion von [ReCl3(NSCl)2(POCl3)] mit Triphenylphosphan. Die Kristallstruktur wurde mit Hilfe von Röntgenbeugungsdaten ermittelt ermittelt (2861 beobachtete unabhängige Reflexe, R = 0,038). Die Verbindung kristallisiert monoklin in der Raumgruppe P21/n mit vier Formeleinheiten pro Elementarzelle. Die Struktur besteht aus [PPh3Cl]⊕-Kationen und Anionen [ReCl4(N2S2)]⊖, in denen das Rhenium oktaedrisch von vier Chlorliganden und den beiden cis-ständigen Stickstoffatomen eines ReN2S2-Fünfringes umgeben ist (Symmetrie C2v). Die ReN-Abstände (181 pm) und die NS-Abstände (152 pm) entsprechen etwa Doppelbindungen; die S—S-Bindungslänge ist mit 253 pm sehr lang. Das IR-Spektrum wird mitgeteilt.
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  • 4
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Properties, and Structure of [2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]-palladium(II) AcetylacetonateThe reaction of Di-μ-chloro-bis[2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]palladium(II) with Thallium(I) acetylacetonate yields [2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]palladium(II) acetylacetonate. The complex crystallizes monoclinic in the space group P21/n with the lattice constants a = 1302.4(3), b = 836.0(2), c = 1341.3(3) pm, β = 93.69(3)°. Pd has a squareplanar coordination by two O atoms of acetylacetonate, the N atom of the imidazole ring, and the C atom of the phenyl group. I.r., n.m.r., and mass spectra are reported.
    Notes: Die Umsetzung von Di-μ-chloro-bis(2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]palladium(II) mit Thallium(I)-acetylacetonat ergibt [2-(1′-methyl-4-imidazolyl)phenyl-1-C,3′-N]palladium(II)-acetylacetonat. Der Komplex kristallisiert monoklin in der Raumgruppe P21/n mit den Gitterkonstanten a = 1302,4(3), b = 836,0(2), c = 1341,3(3) pm, β = 93,69(3)°. Im Molekül ist Pd quadratisch planar von den beiden O-Atomen des Acetylacetonat-Liganden, einem N-Atom des Imidazol-Rings und einem C-Atom der Phenylgruppe umgeben. IR-, NMR- und Massenspektrum werden diskutiert.
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  • 5
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reaction of the Cage-like Vinylsilylated Double Four-ring Silicic Acid [(CH2=CH)(CH3)2Si]8Si8O20 with HSi≡ Containing Compounds and the Preparation of a New PolymerBy means of 29Si, 13C and 1H NMR it has been shown that the compounds ((CH3)3SiO)2CH3SiH and (C2H5)3SiH react completely with the eight vinyl groups of the cage-like silicic acid derivate [(CH2=CH)(CH3)2Si]8Si8O20 (Q8M8V). The reactions do not follow the Markovnikov rule and give derivatives of the formula [((CH3)3SiO)2CH3Si(CH2)2Si(CH3)2]8Si8O20 and [(C2H5)3Si(CH2)2Si(CH3)2]8Si8O20, respectively. The reaction of Q8M8V with the likewise cage-like silicic acid derivative Q8M8H in the molar ratio of 1:1 results in an insoluble polymer consisting of cross-linked double fourring silicic acid units. Due to the sterical hindrance the polymer includes parts of unreacted vinyl and H groups. Molar ratios of 〉 1 result in increasing amounts of a soluble polymer.
    Notes: Mit Hilfe der 29Si-, 13C- und 1H-NMR wird gezeigt, daß mit ((CH3)3SiO)2CH3SiH und (C2H5)3SiH eine vollständige Addition der acht Vinylgruppen des käfigartig aufgebauten Kieselsäurederivats [(CH2=CH)(CH3)2Si]8Si8O20 (Q8M8V) erfolgt. Die Addition verläuft entgegen der Markovnikov-Regel unter Bildung der Kieselsäurederivate [((CH3)3SiO)2CH3Si(CH2)2Si(CH3)2]8Si8O20 bzw. [(C2H5)3Si(CH2)2Si(CH3)2]8Si8O20. Die Reaktion des Q8M8V mit dem ebenfalls käfigartig aufgebauten Kieselsäurederivat Q8M8H führt bei einem Molverhältnis (MV) von 1:1 zu einem unlöslichen Polymer, das aus vernetzten Doppelvierringkieselsäureeinheiten aufgebaut ist und aus sterischen Gründen Anteile unumgesetzter Vinyl- und H-Gruppen enthält. Bei einem MV 〉 1 bilden sich zunehmend in organischen Lösungsmitteln lösliche Polymere.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 589 (1990), S. 175-186 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bis[dichloro-bis(trimethylsilyl)methylalane] - Synthesis and Molecular StructureBis[dichloro-bis(trimethylsilyl)methylalane] 1 is synthesized via a distribution reaction melting AlCl3 and tris[bis(trimethylsilyl)methyl]alane in the stoichiometric ratio of 2:1 at 110°C. A similar reaction for preparing the monochloro analogue 2 gives not the desired compound. 1 dimerizes through Al—Cl bridges; the crystal structure shows a large difference between terminal (206.8 pm) and bridging (228.6 pm Al—Cl distances. Treatment of 1 with potassium in hexane yields only disproportionation products: elemental aluminium), chloro-bis[bis(trimethylsilyl)methyl]alane 2, and tris[bis(trimethylsilyl)methyl]alane. From the reaction of thereby formed KCl with the educt 1 we isolate potassium-[trichloro-bis(trimethylsilyl)methylalanate] 3 as a by-product.
    Notes: Bis[dichlor-bis(trimethylsilyl)methylalan] 1 wird über eine Austauschreaktion in der Schmelze aus Aluminiumtrichlorid und Tris[bis(trimethylsilyl)methyl]alan im Molverhältnis 2:1 bei 110°C dargestellt. Das analoge Chlor-bis[bis(trimethylsilyl)methyl]alan 2 ist auf diesem Weg nicht zugänglich. 1 liegt im gelösten und kristallinen Zustand über Aluminium-Chlor-Brücken dimerisiert vor; die terminale (206,8 pm) ist gegenüber der verbrückenden Al—Cl-Bindung um 21 pm verkürzt. Bei der Reaktion von 1 mit Kalium beobachteten wir ausschließlich Disproportionierung zu elementarem Aluminium, Tris[bis(trimethylsilyl)methyl]alan und Chlor-bis[bis(trimethylsilyl)methyl]alan; dabei gebildetes Kaliumchlorid ergibt mit der Ausgangsverbindung 1 als Nebenprodukt Kalium[trichlor-bis(trimethylsilyl)methylalanat] 3.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 596 (1991), S. 63-72 
    ISSN: 0044-2313
    Keywords: Organic silicic acid derivatives ; cage-like structures ; hydrosilylation ; n.m.r. spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of the Cage-like Silicic Acid Derivative [(CH3)2HSi]8Si8O20 with Unsaturated Organic CompoundsBy 29Si, 1H, and 13C NMR investigations were shown that the eight HSi≡groups of the double four-ring silicic acid derivative [(CH3)2HSi]8Si8O20 react with the following unsaturated compounds: vinylcyclohexene, allyl glycidyl ether, methyl methacrylate, octadecene-1, and styrene. The resulting oily products are soluble in organic solvents. The compounds were characterized by the chemical shifts of the 29Si, 1H, and 13C NMR signals. Their formulae are [C6H9(CH2)2Si(CH3)2]8Si8O20, [CH3OOCCH(CH3)CH2Si(CH3)2]8Si8O20, [CH3(CH2)17Si(CH3)2]8Si8O20 and [C6H5(CH2)2Si(CH3)2]8Si8O20, and [C6H5CH(CH3)Si(CH3)2]8 Si8O20, respectively. Mainly the addition reactions do not follow the Markovnikov rule.
    Notes: 29Si-, 1H- und 13C-NMR-Untersuchungen zeigen, daß das Doppelvierring-kieselsäurederivat [(CH3)2HSi]8Si8O20 mit seinen acht HSi≡Gruppen pro Molekül Additionsreaktionen mit den einfach ungesättigten Verbindungen Vinylcyclohexen, Allylglycidylether, Methacrylsäuremethylester, Octadecen-1 und Styren eingeht. Die Addition erfolgt überwiegend entgegen der Markovnikov-Regel.Als Reaktionsprodukte werden meist ölartige, in organischen Lösungsmitteln lösliche Verbindungen der Formeln [C6H9(CH2)2Si(CH3)2]8Si8O20, [CH3OOCCH(CH3)CH2Si(CH3)2]8Si8O20, CH3(CH2)17Si([CH3)2]8Si8O20 und [C6H5(CH2)2Si(CH3)2]8Si8O20 bzw. [C6H5CH(CH3)Si(CH3)2]8Si8O20 erhalten, die durch die chemischen Verschiebungen der 29Si-, 1H- und 13C-NMR-Signale charakterisiert werden.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Peptide Science 1 (1995), S. 201-206 
    ISSN: 1075-2617
    Keywords: All-aza peptide ; renin inhibitor analogue ; X-ray ; conformation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the first all-aza-amino acid analogue (2) of a peptidic renin inhibitor is described. The X-ray structural analysis and molecular modelling investigations of this novel compound reveal interesting conformational features which have a significant impact on its biological activity. In addition, insight into conformational features of azapeptides in general in comparison with the corresponding purely peptidic compounds is given.
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 1001-1014 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A general expression for the magnetization decay of a multipulse group is derived. This formula is applied to a three-component model of molecular motions in polymer melts. The influence of the several components on the magnetization decay is discussed. The relation of the effective nuclear magnetic relaxation time T2e to the Anderson-Weiss formula is also shown, and an analytical expression for the transverse relaxation in melts is derived. Finally T2e is compared with the relaxation time in the rotating frame T1ρ in the melt. The theoretical results for T2e are tested with measurements of frequency dependence in polyethylene melts.
    Additional Material: 7 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 30 (1992), S. 931-942 
    ISSN: 0887-6266
    Keywords: nuclear magnetic resonance (NMR) relaxation in polymer melts ; relaxation of proton NMR processes in melts (theory) ; chain motions and NMR relaxation in melts ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A theoretical treatment of the nonexponential relaxation behavior of the different proton nuclear magnetic resonance (NMR) relaxation processes in polymer melts is presented. Formulas are derived for a three-component model given by two versions and a homogeneous distribution of correlation times. The theoretical results were tested with measurements of T1, T2e, and T2 as functions of frequency and molecular mass in linear fractionated polyethylene samples. While the T1 relaxation always yields exponential magnetization decays, the T2e and T2 measurements show biexponential relaxation behavior. From the calculations it was found that the correlation time of the local motion is independent of the molecular mass, whereas the correlation time of the slowest motional process increases with M2.8w for the three-component model and with M2.2w for the distribution of correlation times, respectively. © 1992 John Wiley & Sons, Inc.
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