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  • Articles: DFG German National Licenses  (13)
  • Analytical Chemistry and Spectroscopy  (10)
  • Ferulic acid  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Interactions of temperature and ferulic acid stress on grain sorghum and soybeans (1984)
    Springer
    Journal of chemical ecology 10 (1984), S. 161-170 
    Details
    ISSN: 1573-1561
    Keywords: Ferulic acid ; allelopathy ; temperature stress ; sorghum ; soybean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Experiments were conducted to test the hypothesis that alleiopathic effects of ferulic acid (FA) may be altered by the temperature conditions of the growth environment. Growth of grain sorghum and soybean seedlings over a 10-day treatment period showed that a significant interaction effect occurred between environmental temperatures and FA treatments. Sorghum grown with an average day temperature of 37 °C and soybeans grown at 34 °C had greater dry weight reductions caused by FA than when the respective environments were 8 °C and 11 °C lower. The threshold concentration for inhibition of sorghum growth was 0.2 mM FA under the hot conditions and 0.4 mM FA with the cooler conditions. Soybeans were more sensitive than sorghum, and these inhibition thresholds for the hot and cool environments were 0.1 and 0.25 mM FA. These results demonstrate that temperature stress enhances allelochemical inhibition and indicate that interactions with the environment are an important consideration for understanding allelopathy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00987653
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of three phenolic acids on chlorophyll content and growth of soybean and grain sorghum seedlings (1979)
    Springer
    Journal of chemical ecology 5 (1979), S. 815-824 
    Details
    ISSN: 1573-1561
    Keywords: Ferulic acid ; p-coumaric acid ; vanillic acid ; chlorophyll a ; chlorophyll b ; allelopathy ; inhibitors ; soybean ; sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Experiments were designed to test the hypothesis that interference with chlorophyll metabolism may be one mechanism of inhibition of plant growth in allelopathic interactions. Effects of ferulic,p-coumaric, and vanillic acids on soybean and grain sorghum growth and chlorophyll content were quantified and compared after seedlings were treated with these compounds in a nutrient culture. Following a 6-day treatment cycle, dry weights of soybean seedlings were reduced by both 10−3 M and 5 × 10−4 M treatments of ferulic,p-coumaric and vanillic acids. Soybean weight reductions in each case were paralleled by a significant reduction in the concentration (μg Chl/mg dry wt) of chlorophylls a and b and total chlorophyll in the unifoliate leaves. Sorghum seedling growth was also reduced by each of the compounds at the 5 × 10−4 M level, but leaf chlorophyll concentration was not below that of control plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00986566
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of ferulic acid on the mineral nutrition of grain sorghum (1987)
    Springer
    Plant and soil 98 (1987), S. 99-109 
    Details
    ISSN: 1573-5036
    Keywords: Allelopathy ; Ferulic acid ; Magnesium ; Mineral content ; Phosphorus ; PotassiumSorghum bicolor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two week old sorghum seedlings (Sorghum bicolor L. Moench) were treated with ferulic acid added to the nutrient solution. Effects on tissue concentration of P, K, Mg, Ca, Fe, and Zn were evaluated after 3 and 6 days. Treatemnts of 0.25 mM ferulic acid approximated the growth inhibition threshold, and after 6 days 0.5 mM treated plants weighed less than controls. Both treatments reduced the P content of the roots and shoots at the 3- and 6-day harvests in three replicate experiments. Roots of treated plants at both harvests had a lower concentration of K and Mg. These reductions in P, K, and Mg were most extensive from the 0.5 mM ferulic acid regime. In some cases at both harvests, shoot K was lower and Mg was higher than control tissue. Ferulic acid effects at the 3-day harvest included an elevation of Ca and depression of Fe in shoots. Changes in nutrient content preceded measurable differences in plant weight. These data indicate that one mechanism of growth inhibition by this allelochemical may be an alteration of nutrient balance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02381731
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  • 4
    Electronic Resource
    Electronic Resource
    Kinetic energy effects in an ion ensemble subjected to mass-selective isolation and resonance excitation: A simulation study (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 499-509 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simulation study is described of the behaviour of ions confined in a quadrupole ion trap during each of two separate operations of a tandem mass spectrometric experiment. The two operations are those of mass-selective ion isolation and mass-selective resonance excitation to the point of ion ejection from the ion trap. The method of mass-selective ion isolation simulated is that of consecutive ion isolation. Simulation data indicate that the collisional history of the ions prior to the isolation process can greatly influence the degree to which ions survive this process. Simulation data for mass-selective resonance ejection are compared with experimental data obtained with a Finnigan-MAT ion trap mass spectrometer. In each operation, the facility with which ions absorb energy from the field within the ion trap, whether this field is derived from the R.F. drive potential or a supplementary potential, can determine the extent to which ions are retained within the ion trap during the two mass-selective operations described.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210280506
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  • 5
    Electronic Resource
    Electronic Resource
    Negative-ion mass spectrometry in a commercial gas chromatography/ion-trap mass spectrometer system (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 1302-1309 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Commercial gas chromatography quadrupole ion-trap mass spectrometer (GC/ITMS) instruments have been used in a novel way for the study of negative ions formed from perfluorotributyl-amine and polychlorinated biphenyl compounds. Negative ions, formed during a normal electron impact ionization period in which 70 eV electrons were used, were isolated in an ion trap by the application of a negative DC voltage to the ring electrode that caused all positive ions to be ejected from the ion trap; in the subsequent analytical scan, negatives ions were detected with an electron multiplier biased normally so as to detect positive ions. The major negative-ion species detected from FC-43 were m/z 252 to m/z 633; 34 other negative-ion species were detected also, though in low abundance. The observed negative-ion mass range extended from m/z 252 to m/z 633. The signal-to-noise ratio of negative-ion mass spectra was enhanced by operation of the GC/MS instrument in GC mode and averaging the mass spectra acquired. In an examination of 3 hexachlorobiphenyl compounds, the molecular anion cluster around m/z 360 for the non-ortho-substituted congener 169 was observed with a signal-to-noise ratio of ca. 20 for 90 pg injected on column: the response for congener 169 was greater than that for congener 156 (mono-ortho-substituted) which, in turn, was greater than that for congener 153 (di-ortho-substituted).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290091316
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    The influence of collisional cooling on boundary-activated decomposition in an ion-trap mass spectrometer (1993)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 929-934 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: When the working point of a precursor ion confined within a quadrupole ion trap is moved to the vicinity of a boundary of the stability diagram, fragmentation of the precursor ion can be induced by virtue of energy gained from the radio-frequency trapping field. This behaviour is known as the ‘border effect’. When the isolated precursor ion is subjected to a cooling period of variable duration, in the presence of helium buffer gas and prior to experiencing the ‘border effect’, a high degree of control of the fragmentation pattern is achieved. The cooling period causes decreases in both ion kinetic energy and ion axial excursions. From this preliminary study, it is suggested that the deposition of internal energy during the ‘border effect’ can be varied by changing the duration of the cooling period. In addition to a degree of control of internal energy deposition, the amount of energy which can be deposited in this manner, though unknown, appears to exceed those energy levels achievable with resonance excitation and the ‘border effect’ without collisional cooling, in that an additional fragmentation channel is accessed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290071014
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Enhanced mass resolution in a quadrupole ion trap (1993)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 43-45 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The versatility of the quadrupole ion trap as a mass spectrometer in which the mass resolution may be varied over a wide range has been demonstrated. Mass resolution of 0.8 × 107 and 1.2 × 107 have been obtained for ions of m/z 414 and m/z 614, respectively, well in excess of the normal value of 3m, where m is the mass of ion. At the highest mass resolution, peak-widths at half-maximum are but 52 × 10-6 u. While it has been shown previously that enhanced mass reslution in the quadrupole ion trap can be achieved by reduction of the mass scanning rate, the range of mass resolutions reported here were achieved by reducing the mass scanning rate, in stages, by an overall factor of ca 5.5 × 104.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290070111
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    A dynamic nuclear magnetic resonance study of nitrogen inversion in N,N'-dimethylimidazolidine (1979)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 12 (1979), S. 362-364 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 251 MHz 1H and the natural-abundance 63.1 MHz 13C NMR spectra of N,N'-dimethylimidazolidine have been measured from -50 to -170°C. Below about -140°C. nitrogen inversion in the compound becomes slow on the NMR time scale and both the 1H and the 13C spectra indicate that it exists in solution as a mixture of cis and trans conformations having nearly the same energies. The free-energy barrier (ΔG≠) for nitrogen inversion in N,N'-dimethylimidazolidine is 6.4 kcal mol-1, a value which is 1.5 kcal mol-1 lower than that for N-methylpyrrolidine.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270120607
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  • 9
    Electronic Resource
    Electronic Resource
    Magnetic resonance study of diastereomeric interactions of nitroaromatic sulfxides with alcohols in solution (1984)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 22 (1984), S. 539-542 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of optically active (1R,2R)- and (1S,2R)-2-deuterio-2,3-dihydro-2-methyl-6-nitrobenzothiophene-1-oxide (3 and 4) is described. Several racemic aryl methyl carbinols in the presence of 3 or 4 give different chemical shifts for enantiomeric CH, CH3 and OH protons. These chemical shift differences are larger than those observed in analogous sulfoxide-alcohol pairs without nitro groups. Quinine and cinchonidine cause observable non-equivalence of methylene and aromatic protons in racemic 4. The magnitude of the diastereomeric shift difference is sensitive to temperature, solvent, concentration, nature of the π system and steric effects.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270220902
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    13C n.m.r. chemical shifts of carbodiimides (1976)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 8 (1976), S. 327-328 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C n.m.r. chemical shifts of the sp-hybridized carbons in dialkylcarbodiimides have values of δc ≃ 140. These shifts are compared with those of similarly hybridized carbons occuring in other classes of compounds.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270080613
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