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  • synchronous fluorescence spectroscopy  (2)
  • Ascaris suum  (1)
  • 1995-1999  (3)
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  • 1995-1999  (3)
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  • 1
    Digitale Medien
    Digitale Medien
    Spectroscopic properties of dissolved humic substances - a reflection of land use history in a fen area (1999)
    Springer
    Biogeochemistry 47 (1999), S. 219-238 
    Details
    ISSN: 1573-515X
    Schlagwort(e): dissolved humic substances ; FTIR spectroscopy ; land use history ; peat ; synchronous fluorescence spectroscopy ; UV/VIS spectroscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract The elemental composition and spectroscopic properties of dissolved fulvic acids isolated from different sampling media (topsoil, ground and surface water) of a natural fen area (high portion of organic soils) were examined to reveal the effects of land use history. These effects need to be known if dissolved humic substances are to be a major factor in identifying the impact of present and future changes in land use. Dissolved fulvic acids (topsoil, groundwater) from highly degraded peatlands (due to a long-term agricultural use) exhibit lower C/N ratios, higher absorption in the UV spectra, and higher absorption at 1,620 cm−1 in the FTIR spectra compared with fulvic acids from relatively intact peatlands. These properties illustrate that long-term agricultural use with high inputs results in increased aromatic structures and a further humification of dissolved fulvic acids due to very strong peat decomposition compared with relatively intact peatlands. Synchronous fluorescence spectra also indicate the higher level of aromatic structures within fulvic acids isolated from sites with long-term agricultural use (high peat decomposition) compared with a land use history resulting in a lower peat decomposition. The different sources of fulvic acids in surface water (precipitation, runoff, interflow, groundwater) are the main reason for these effects not being detected in fulvic acids isolated from surface water. Short-term changes in land use characterized by a transition from crop farming to an unimproved grassland were found not to affect the spectroscopic properties of dissolved fulvic acids. A humification index deduced from the synchronous fluorescence spectra is proposed. We have strong evidence that dissolved humic substances indicate changes in the environmental conditions (both anthropogenic and natural) of wetlands with a high proportion of organic soils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006134214244
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Spectroscopic properties of dissolved humic substances — a reflection of land use history in a fen area (1999)
    Springer
    Biogeochemistry 47 (1999), S. 219-238 
    Details
    ISSN: 1573-515X
    Schlagwort(e): dissolved humic substances ; FTIR spectroscopy ; land use history ; peat ; synchronous fluorescence spectroscopy ; UV/VIS spectroscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract The elemental composition and spectroscopic properties of dissolved fulvic acids isolated from different sampling media (topsoil, ground and surface water) of a natural fen area (high portion of organic soils) were examined to reveal the effects of land use history. These effects need to be known if dissolved humic substances are to be a major factor in identifying the impact of present and future changes in land use. Dissolved fulvic acids (topsoil, groundwater) from highly degraded peatlands (due to a long-term agricultural use) exhibit lower C/N ratios, higher absorption in the UV spectra, and higher absorption at 1,620 cm−1 in the FTIR spectra compared with fulvic acids from relatively intact peatlands. These properties illustrate that long-term agricultural use with high inputs results in increased aromatic structures and a further humification of dissolved fulvic acids due to very strong peat decomposition compared with relatively intact peatlands. Synchronous fluorescence spectra also indicate the higher level of aromatic structures within fulvic acids isolated from sites with long-term agricultural use (high peat decomposition) compared with a land use history resulting in a lower peat decomposition. The different sources of fulvic acids in surface water (precipitation, runoff, interflow, groundwater) are the main reason for these effects not being detected in fulvic acids isolated from surface water. Short-term changes in land use characterized by a transition from crop farming to an unimproved grassland were found not to affect the spectroscopic properties of dissolved fulvic acids. A humification index deduced from the synchronous fluorescence spectra is proposed. We have strong evidence that dissolved humic substances indicate changes in the environmental conditions (both anthropogenic and natural) of wetlands with a high proportion of organic soils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00994924
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Structural analysis of neutral glycosphingolipids from Ascaris suum adults (Nematoda: Ascaridida) (1997)
    Springer
    Glycoconjugate journal 14 (1997), S. 389-399 
    Details
    ISSN: 1573-4986
    Schlagwort(e): arthro-series glycosphingolipids ; Ascaris suum ; (iso-branched) C17 sphingoid-bases ; neutral glycosphingolipids ; parasitic nematodes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The neutral glycosphingolipid fraction from adults of the pig parasitic nematode, Ascaris suum, was resolved into four components on thin-layer chromatography. The high-performance liquid chromatography-isolated components were structurally analysed by: methylation analysis; exoglycosidase cleavage; gas-liquid chromatography/mass spectrometry; liquid secondary-ion mass spectrometry; and, in particular, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Their chemical structures were determined as: Glc(β1-1)ceramide, Man(β1-4)Glc(β1-1)ceramide, GlcNAc(β1-3)Man(β1-4)Glc(β1-1)ceramide and Gal(α1-3)GalNAc(β1-4)GlcNAc(β1-3)Man(β1-4)Glc(β1-1)ceramide; and were characterized as belonging to the arthro-series of protostomial glycosphingolipids. No glycosphingolipid component corresponding to ceramide tetrasaccharide was detected during these analyses. The ceramide composition of the parent glycosphingolipids was dominated by the 2-(R)-hydroxy C24:0 fatty acid, cerebronic acid, and C17 sphingoid-bases: 15-methylhexadecasphing-4-enine and 15-methylhexadecaphinganine in approximately equal proportions. The component ceramide monohexoside was characterized by an additional 15-methylhexadecaphytosphingosine. Abbreviations: CDH, ceramide dihexoside; Cer, ceramide; CMH, ceramide monohexoside; CPH, ceramide pentahexoside; CTH, ceramide trihexoside; CTetH, ceramide tetrahexoside; Hex, hexose; HexNAc, N-acetylhexosamine; HPTLC, high-performance thin-layer chromatography; LSIMS, liquid secondary-ion mass spectrometry; MALDI-TOF-MS, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; N-, Nz- and A-glyco(sphingo)lipids, neutral, neutralzwitterionic and acidic glyco(sphingo)lipids, respectively
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018530914067
    Standort Signatur Erwartet Verfügbarkeit
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    Artikel (Nationallizenzen)
    Volltext
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