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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 287-388 (1998), S. 349-353 
    ISSN: 1573-5117
    Keywords: competition ; threshold food level ; Rotifera ; temperature ; Brachionus ; Synchaeta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The numerical response of populations to different food concentrations in an important parameter to be determined for a mechanistic approach to interspecific competition. Theory predicts that the species with the lowest food level (TFL) should always be the superior competitor if only one food source is offered. However, TFLs are not species specific constants but may change along environmental gradients such as food size or temperature. The hypothesis that temperature differentially affects the TFLs of three planktonic rotifers (Asplanchna priodonta, Brachionus calyciflorus and Synchaeta pectinata) was tested in laboratory experiments. Numerical responses were assessed for all three rotifers at 12, 16, 20, 24 and 28°C with Cryptomonas erosa as food alga. Growth rates of all three rotifers at high food concentrations (1 mg C l-1) increased as temperature increased until the limits of thermal tolerance were reached. This increase was very pronounced for Brachionus, but less for Synchaeta which already had relatively high growth rates at 12°C. Along the temperature gradient, the TFLs of Synchaeta increased from 0.074 to 0.66 mg C l-1, whereas those of Asplanchna and Brachionus stayed relatively constant at 0.3 and 0.2 mg C l-1, respectively. Hence, the zero net growth isocline (ZNGI) of Synchaeta crossed those of Brachionus and Asplanchna at 16 and 20.5°C, respectively. The results suggest that Synchaeta is better adapted to low temperatures than the other two rotifers and should be the superior competitor below 16°C.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 387-388 (1998), S. 349-353 
    ISSN: 1573-5117
    Keywords: competition ; threshold food level ; Rotifera ; temperature ; Brachionus ; Synchaeta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The numerical response of populations to different food concentrations in an important parameter to be determined for a mechanistic approach to interspecific competition. Theory predicts that the species with the lowest food level (TFL) should always be the superior competitor if only one food source is offered. However, TFLs are not species specific constants but may change along environmental gradients such as food size or temperature. The hypothesis that temperature differentially affects the TFLs of three planktonic rotifers (Asplanchna priodonta, Brachionus calyciflorus and Synchaeta pectinata) was tested in laboratory experiments. Numerical responses were assessed for all three rotifers at 12, 16, 20, 24 and 28°C with Cryptomonas erosa as food alga. Growth rates of all three rotifers at high food concentrations (1 mg C l-1) increased as temperature increased until the limits of thermal tolerance were reached. This increase was very pronounced for Brachionus, but less for Synchaeta which already had relatively high growth rates at 12°C. Along the temperature gradient, the TFLs of Synchaeta increased from 0.074 to 0.66 mg C l-1, whereas those of Asplanchna and Brachionus stayed relatively constant at 0.3 and 0.2 mg C l-1, respectively. Hence, the zero net growth isocline (ZNGI) of Synchaeta crossed those of Brachionus and Asplanchna at 16 and 20.5°C, respectively. The results suggest that Synchaeta is better adapted to low temperatures than the other two rotifers and should be the superior competitor below 16°C.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-1948
    Keywords: Pd-catalyzed P-C coupling ; Nucleophilic phosphanylation ; Mono- and bisphosphonated phosphanes ; Monoesters ; Water solubility ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The triphenylphosphane derivatives 2a and 5, bearing one and two phosphonic ester groups, are accessible in high yields by consecutive Pd-catalyzed P-C coupling reactions of p-bromoiodobenzene with Ph2PH and PhPH2, respectively, and then with diethyl phosphite. Ester hydrolysis yields the highly water-soluble sodium salts of mono- and bis-phosphonated triphenylphosphane, 3a and 6, respectively. On reaction of the p- and m-fluorophenylphosphonic diethyl esters 7a, 7b with Ph2PK and subsequent ester hydrolysis the isomeric disodium (diphenylphosphano)phenylphosphonates 3a, 3b were obtained. The X-ray structure of Ph2P(C6H4-m-PO3Na2) · 5.5 H2O · iPrOH (space group Cmc21) has been determined. In the solid state, it forms a layer structure with hydrophilic (PO32-, H2O, iPrOH) and hydrophobic (Ph2P) compartments, in which the PO32- anionic groups are not engaged in coordination of the sodium cations.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1434-1948
    Keywords: (R)-(+)-2,3-Epoxy-1-propanol ; 2,3-Dihydroxyalkyl phosphanes ; 1,3,2-Dioxaborolane ; 1,3-Dioxolane ring ; Enantiopure phosphanes ; Complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of (R)-(+)-2,3-epoxy-1-propanol with Ph2PH, Ph(Me)PH, or PhPH2 in the superbasic medium KOH/DMSO affords the novel chiral phosphanes 1a-1c. While 1a is obtained enantiomerically pure, 1b and the secondary phosphane 1c are formed as mixtures of diastereoisomers (RPRC, SPRC) with homochiral β carbon atoms. Derivatization of 1a with phenylboronic acid or 2,2-dimethoxypropane yields 2a and 3a with 1,3,2-dioxaborolane and 1,3-dioxolane ring systems, respectively. The X-ray structure of 2a (space group P21) reveals the presence of four molecules of R configuration in the unit cell. Nucleophilic phosphanylation of (R)-(-)-2,3-O-isopropylideneglycerol tosylate with Ph2PH, Ph(Me)PH, or PhPH2 yields chiral 3a-3d. Compound 3b was obtained enantiomerically pure. The secondary phosphane 3c has been employed in syntheses of the hydrophilic tertiary phosphanes 3e, 3f and of the novel bidentate phosphane ligands 3g, 3h, all of which have homochiral β carbon atoms. PdII complexes PdL2Cl2 of 1a, 2a, 3a (L) are formed as mixtures of cis/trans isomers. RhI complexes of 1a, 3a, and bidentate 3h have also been synthesized.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-1948
    Keywords: Nucleophilic phosphanylation ; Phosphanylphthalic acid ; Phosphanylphenylacetic acid ; Benzylaminophosphanes ; Water solubility ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral- and multiply-carboxylated phosphanes and phosphanyl derivatives of benzoic and phthalic acids (1-9) are accessible in high yields by nucleophilic phosphanylation of potassium or lithium salts of commercially available fluorobenzoic and 3-fluorophthalic acids with Ph2PH, Ph2PK, PhPLi2 Ph(K)P-(CH2)3-P(K)Ph in superbasic media (DMSO/KOH) or in THF and DME. The hitherto unknown phosphanylphenylacetic acids (10-13) and phosphanylbenzylamines RR′P-C6H4-CH2- NH2 (14-19, R, R′ = H, Me, Ph) with unsubstituted amino groups were also synthesized by this method. The diphenylphosphanyl derivatives 14-16 (R, R′ = Ph) are accessible by an alternative method involving LiAlH4 reduction of the phosphanylbenzonitriles (20-22), which were obtained in high yields by nucleophilic phosphanylation of the corresponding fluoro- or chlorobenzonitriles. The novel bidentate phosphanylbenzonitrile 23 has also been obtained using this synthetic route. All compounds were completely characterized by elemental analysis, NMR spectroscopy, and mass spectrometry.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 79 (1967), S. 692-692 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 80 (1968), S. 240-240 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 80 (1968), S. 318-318 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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