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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Queueing systems 8 (1991), S. 323-356 
    ISSN: 1572-9443
    Keywords: Infinite server ; batch arrival ; Markov renewal input ; customer dependence ; analytical result
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract An important property of most infinite server systems is that customers are independent of each other once they enter the system. Though this non-interacting property (NIP) has been instrumental in facilitating excellent results for infinite server systems in the past, the utility of this property has not been fully exploited or even fully recognized. This paper exploits theNIP by investigating a general infinite server system with batch arrivals following a Markov renewal input process. The batch sizes and service times depend on the customer types which are regulated by the Markov renewal process. By conditional approaches, analytical results are obtained for the generating functions and binomial moments of both the continuous time system size and pre-arrival system size. These results extend the previous results on infinite server queues significantly.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Queueing systems 22 (1996), S. 129-144 
    ISSN: 1572-9443
    Keywords: Infinite server ; batch arrival ; batch service ; analytical results
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Service systems with queueing often have both batch arrivals and batch services. This paper focuses on the number of busy servers and waiting customers in theGI X/MR/∞ system. For the number of busy servers, we obtain a recursive relation for the partial binomial moments in terms of matrices and explicit expressions for the marginal binomial moments. Special cases are also discussed to provide a more heuristic understanding of the model.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Queueing systems 2 (1987), S. 363-372 
    ISSN: 1572-9443
    Keywords: Infinite server ; impatient customers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract An infinite server queue is considered where customers have a choice of individual service or batch service. Transient results have been obtained for the first two moments of the system size distribution. Waiting time distribution is important in system evaluation and steady state results are obtained.
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  • 4
    ISSN: 0170-2041
    Keywords: Gloeosporone ; Colletotrichum gloeosporioides ; 4-Pentynoic acid ; Oxidation, alkyne → 1,2-diketone ; 23Na NMR ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gloeosporon - Ein Pilzkeimungs-Selbsthemmer mit Macrolidstruktur. - Totalsynthese und AktivitätAusgehend von (S)- oder (R)-4-Brom-1,2-epoxybutan [kommerziell erhältlich oder leicht und in hoher Ausbeute aus (S)- bzw. (R)- Apfelsäure zugänglich] wurden die beiden Enantiomeren des Keimungs-Selbstinhibitors Gloeosporon hergestellt. Die absolute Konfiguration des Naturstoffes wurde damit als 4S,7R,13R bewiesen. Mikrobiologische Tests zeigen, daß beide Enantiomere von Gloeosporon die Keimungshemmung der Sporen von Colletotrichum gloeosporioides bewirken, und daß (-)-Gloeosporon gegenüber einer Reihe von anderen Pilzen aktiv ist. Zur Aufklärung des Wirkungsmechanismus wurden 23Na-NMR- sowie Ionenselektivitätsmessungen durchgeführt; es konnten keine Gloeosporon-Metallion-Wechselwirkungen nachgewiesen werden.
    Notes: Starting with (S)- or (R)-4-Bromo-1,2-epoxybutane [commercially available or readily made from (S)- or (R)-malic acid], both enantiomers of the germination self-inhibitor gloeosporone were synthesized. The absolute configuration of the natural product was thus proven to be 4S,7R,13R. Microbiological studies showed that both enantiomers of the compound cause inhibition of germination in spores of Colletotrichum gloeosporioides, and that (-)-gloeosporone is also active against a variety of other fungi. In order to gain some insight into the mode of action, 23Na NMR measurements and ion-selectivity studies were undertaken; none of these experiments provided evidence for a gloeosporone-metal ion interaction.
    Additional Material: 1 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 20 (1985), S. 10-13 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positive ion electron impact mass spectral data for the four isomeric 17ξ-hydroxy-17ξ-methyl-5ξ-androstane C(3) ketones and the eight isomeric C(3ξ) alcohols are reported. In contrast to earlier reports, no general correlation was observed between the [M—H2O]+·/[M]+· ratio and the configuration at C(17). The ratios of the intensity of several fragment ions to that of the molecular ion do differentiate between the 5α- and 5β-isomers in both C(3) ketones and alcohols, the extent of fragmentation being greater for 5β-steroids. All of these fragments probably involve elimination of a water molecule at some stage in their formation. Elimination of water is also enhanced for 3α- v. 3β-hydroxysteroids, particularly in a 5β-isomer.
    Additional Material: 2 Tab.
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Bioluminescence and Chemiluminescence 5 (1990), S. 243-250 
    ISSN: 0884-3996
    Keywords: Mononuclear leukocytes ; monocytes ; chemiluminescence ; anti-D lgG ; erythrophagocytosis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A luminol-dependent chemiluminescence assay for the assessment of the phagocytosis of erythrocytes sensitized with anti-D IgG immunoglobulin by mononuclear leukocytes is described. The mononuclear leukocytes were obtained by apheresis enriched by centrifugation through a density gradient and stored in liquid nitrogen before use. The total reaction mixture, consisting of mononuclear leukocytes-luminol-erythrocytes (either anti-D IgG sensitized or unsensitized controls) was 500 μl, light detection was by an LKB 1251 luminometer. Peak luminescence was seen between 35-45 minutes, the reaction being exhausted by 120 minutes. Determination of the reproducibility of the assay gave intra- and inter-assay coefficients of variation of 5% and 13% respectively. We found the chemiluminescent response to be affected by the number of erythrocytes used in the assay and by the composition of the medium in which the cells were resuspended, particularly the pH at the initiation of the assay. We also compared the chemiluminescence assay to a microscopic phagocytic assay and found the results virtually identical. However, the former chemiluminescence assay was much easier to perform, marginally more sensitive, less laborious and eliminated any possibility of subjective error.
    Additional Material: 6 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 25 (1987), S. 25-30 
    ISSN: 0749-1581
    Keywords: NMR ; 4-en-3-one steroids ; Conformational analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: NMR spectral data are given for the A-ring in ten 4-en-3-one steroids, and the strategy of the spectral analysis is described. The data are interpreted in terms of an equilibrium between normal and inverted half-chair conformations, with the normal conformation predominant in all cases except when 2β-acetoxy substitution forces inversion. Substitution at the 17α position has no measurable effect upon the A-ring conformation while 6α and 19-nor substitution have only a small effect. Unsaturation at the C-5 position results in a flattened A-ring. The results obtained from NMR are compared with those obtained by x-ray crystallography. The A-ring conformation shows far less variation in solution than it does in the solid.
    Additional Material: 5 Ill.
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  • 8
    ISSN: 0749-1581
    Keywords: 1H NMR ; 13C NMR monomethyl/dimethyl 5α-androstan-3-ones ; Steroid ; Ring A conformation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ring A proton shifts and couplings and 13C shifts of all carbons are given for 17β-acetoxy-2α-methyl- and 17β-methoxy-2β-methyl-5α-androstan-3-one and 2,2-dimethyl-17β-methoxy-5α-androstan-3-one. It was concluded that the 2β-methyl derivative exists with ring A in a regular chair conformation while the 2β-methyl derivative exists with ring A in an inverted boat conformation with C-2 and C-5 at the bow/stern positions. The data for 2,2-dimethyl-17β-methoxy-5α-androstan-3-one suggest an equilibrium of these two conformers.
    Additional Material: 3 Ill.
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  • 9
    ISSN: 0749-1581
    Keywords: 1H NOESY ; 183W NMR ; x-ray diffraction ; Pyrazolylborate ; π-Allyl complexes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2D1H NOESY and inverse detected 183W NMR measurements for the pseudo-octahedral η3-allyl complexes W(CO)2(Tp′)(η3-CH2CHCDPh) (1) and W(CO)2(Tp′)(η3-CH2CHCHCH3) (2), where Tp′ = hydridotris(3,5-dimethylpyrazolyl)borate are reported. The observed solution structure for 1 differs from that found in the solid-state via x-ray diffraction (isomers can arise due to allyl rotation and/or coordination of either allyl face). Crystal data for 1: WC26H31BN6O3, space group P21/c, a = 9.775(1) Å, b = 17.360(2) Å, c = 16.144(5) Å, β = 102.26(2)°, V = 2677(1) Å3, Z = 4.
    Additional Material: 4 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 31 (1993), S. 17-22 
    ISSN: 0749-1581
    Keywords: NMR ; Coupling constants ; NOE ; Conformation ; Configuration C-20 substituted 5β,14β-pregnanes,5β-pregn-14-enes and 21-nor-5β,14β-pregnanes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Coupling constants and nuclear Overhauser effect measurements were used to establish the C-20 configuration and the conformation about the C-17—C-20 bond in a series of sixteen C-20-substituted 5β,14β-pregn-14-enes. In the 14β-pregnane series the conformation of the C-17 side-chain is variable, whereas in the pregnenes the side-chain adopts a conformation in which H-17 is anti to H-20. The C-17 side-chain conformation of two 21-nor-5β,14β-pregnanes was also determined. In the 21-nor compounds a C-20 hydroxyl adopts a conformation anti to H-17, while a C-20 nitro group is anti to C-13.
    Additional Material: 2 Ill.
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