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  • 1
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A model was developed to describe the effects of temperature and leaf wetness duration in controlled-environment experiments on the development of light leaf spot on oilseed rape (cv. Bristol) leaves inoculated with Pyrenopeziza brassicae conidial suspensions. A Gompertz function was used to describe the progress with time in percentage leaf area with sporulation, and included the parameters maximum percentage leaf area with sporulation (c); maximum rate of increase in percentage leaf area with sporulation (r); and latent period (l, the time from inoculation until the leaf area with sporulation reached 37% of c). The effects of leaf wetness duration on c and r were also described with Gompertz functions, which included the parameters minimum leaf wetness duration (vc or vr); and maximum of c (mc) or maximum of r (mr). The effects of temperature on mc, vc and vr were described by quadratic functions, and the effect of temperature on mr was described by a linear function. The combined model described the progress with time in percentage leaf area with sporulation, including the effects of temperature and leaf wetness duration on the parameters c, r and l. It generally fitted well to the observed data. Latent periods in previously published experiments were predicted accurately by the model, but percentage leaf area with sporulation was not. Assuming a great number of conidia were dispersed and infection occurred when there was 2 mm h−1 rain for 0·5 h, the model estimates for latent period were used to predict the dates when large increases in light leaf spot severity occurred in experiments at Rothamsted on winter oilseed rape (cv. Bristol) under natural conditions in 1998/99 and 1999/2000. The predictions agreed with the observations.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Experiments in controlled environments were carried out to determine the effects of temperature and leaf wetness duration on infection of oilseed rape leaves by conidia of the light leaf spot pathogen, Pyrenopeziza brassicae. Visible spore pustules developed on leaves of cv. Bristol inoculated with P. brassicae conidia at temperatures from 4 to 20°C, but not at 24°C; spore pustules developed when the leaf wetness duration after inoculation was longer than or equal to approximately 6 h at 12–20°C, 10 h at 8°C, 16 h at 6°C or 24 h at 4°C. On leaves of cvs. Capricorn or Cobra, light leaf spot symptoms developed at 8 and 16°C when the leaf wetness duration after inoculation was greater than 3 or 24 h, respectively. The latent period (the time period from inoculation to first spore pustules) of P. brassicae on cv. Bristol was, on average, approximately 10 days at 16°C when leaf wetness duration was 24 h, and increased to approximately 12 days as temperature increased to 20°C and to 26 days as temperature decreased to 4°C. At 8°C, an increase in leaf wetness duration from 10 to 72 h decreased the latent period from approximately 25 to 16 days; at 6°C, an increase in leaf wetness duration from 16 to 72 h decreased the latent period from approximately 23 to 17 days. The numbers of conidia produced were greatest at 12–16°C, and decreased as temperature decreased to 8°C or increased to 20°C. At temperatures from 8 to 20°C, an increase in leaf wetness duration from 6 to 24 h increased the production of conidia. There were linear relationships between the number of conidia produced on a leaf and the proportion of the leaf area covered by ‘lesions’ (both log10-transformed) at different temperatures.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 52 (1996), S. 1663-1666 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 49 (1993), S. 2042-2045 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 411-413 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Pharmacology, Biochemistry and Behavior 48 (1994), S. 833 
    ISSN: 0091-3057
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0044-2313
    Keywords: Arylxenon trifluoromethanesulfonates ; electrophilic aromatic substitution ; xenontrifluoroacetate trifluoromethanesulfonate ; NMR spectra ; X-ray crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die direkte Synthese von Arylxenontrifluormethansulfonaten durch elektrophile SubstitutionBei der Reaktion von Xenonbis(trifluoracetat) mit Trifluormethansulfonsäure wird die neue, hochreaktive, unsymmetrische Xenon-Sauerstoff-Verbindung CF3COOXeOSO2CF3 erzeugt. Benzolderivate mit elektronenziehenden Substituenten wie F, CF3, Cl und NO2 werden von diesem Intermediat unter Bildung von Arylxenontrifluormethansulfonaten elektrophil angegriffen. Über diese Eintopfsynthese wurden Trifluormethansulfonate mit den Kationen [Xe(2,4,6-F3C6H2)]+, [Xe(2-F-5-NO2C6H3)]+, [Xe(2-F-5-CF3C6H3)]+ und [Xe(3,5-(CF3)2C6H3)]+ synthetisiert. Alle Verbindungen wurden durch ihre NMR-, Massen- und Schwingungsspektren charakterisiert.Zusätzlich wurden mehrere neue Arylxenontrifluormethansulfonate als Produkte der Umsetzungen von 1,3-F2C6H4 und weiteren desaktivierten Benzolen mit Xenon(trifluoracetat)trifluormethansulfonat anhand der 129Xe-NMR-Spektren identifiziert.Fluorsubstituenten in ortho-Position zu Xenon erhöhen signifikant die thermische Stabilität der Arylxenontrifluormethansulfonate.Die Molekülstruktur von [Xe(2,6-F2C6H3)][OSO2CF3] wurde durch eine Einkristallröntgenstrukturanalyse bestimmt. Die Arylxenoneinheit koordiniert schwach mit einem Sauerstoffatom des CF3SO3-Anions. Die Verbindung kristallisiert in der triklinen Raumgruppe mit a = 880.9(3) pm, b = 1093.9(5) pm, c = 1209.8(5) pm, α = 89.04(4)°, β = 74.23(3)°, γ = 86.03(3)°, Z = 4.
    Notes: The reaction of xenonbis(trifluoroacetate) and trifluoromethanesulfonic acid (triflic acid) gave the new, highly reactive unsymmetrical xenon-oxo species CF3COOXeOSO2CF3. Benzene derivates, containing electron withdrawing substituents such as -F, -CF3, -Cl or -NO2 were electrophilic attacked by this intermediate to yield arylxenon trifluoromethanesulfonates. Via this one-pot synthesis trifluoromethanesulfonates with the cations [Xe(2,4,6-F3C6H2)]+, [Xe(2-F-5-NO2C6H3)]+, [Xe(2-F-5-CF3C6H3)]+ and [Xe(3,5-(CF3)2C6H3)]+ were prepared. All compounds were characterized by their NMR, mass, and vibrational spectra.Additionally, several new arylxenon trifluoromethanesulfonates were detected by 129Xe-NMR spectroscopy as products of the reaction of 1,3-F2C6H4 and further deactivated benzenes with xenontrifluoroacetate trifluoromethane sulfonate.Fluoro substituents in ortho position to xenon significantly increase the thermal stability of the arylxenon trifluoromethanesulfonates obtained.The molecular structure of [Xe(2,6-F2C6H3)][OSO2CF3] was determined by single crystal diffraction methods. The arylxenon unit is weakly coordinated by one oxygen atom of the CF3SO3 anion. The salt crystallizes in the triclinic space group P1, a = 880.9(3) pm, b = 1093.9(5) pm, c = 1209.8(5) pm, α = 89.04(4)°, β = 74.23(3)°, γ = 86.03(3)°, Z = 4.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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