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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    ISSN: 0168-1176
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    ISSN: 0300-9629
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    ISSN: 0300-9629
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    ISSN: 0300-9629
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 23 (1996), S. 266-272 
    ISSN: 1432-0789
    Keywords: Soil organic matter ; Microbial activity ; Groundwater contamination ; Pesticides ; Spodic horizons ; Landscape planning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In sandy gleyic soils with a low groundwater table under arboriculture in Northwest Germany, a wide variation of groundwater pollution by pesticides has been observed. We therefore examined data on microbial activity and soil organic matter composition by wet chemistry, cross-polarization magic-angle spinning and 13C nuclear magnetic resonance, and pyrolysis-field ionization mass spectromy. However, neither microbial activity nor the soil organic matter composition of cultivated topsoils explained the differences in xenobiotic leaching into the groundwater. Data from Anthrosols suggested that these soils have a higher capacity for pesticide bonding because of high amounts of aromatic and carboxylic C moieties in the soil organic matter. However, despite the same pesticide inputs and time of application, the leached output from these soils was higher than that from the Podzols. Initial data from subsoil investigations suggest that the presence of a spodic horizon most likely reduces groundwater pollution by pesticides. Studies to assess fixation capacity and desorption kinetics in Bh horison seem warranted.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 12 (1991), S. 81-88 
    ISSN: 1432-0789
    Keywords: Fertilization experiment ; Soil organic matter ; Soil particle-size fractions ; Pyrolysis-field ionization mass spectrometry ; Nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The influence of more than 100 years of fertilization with farmyard manure on soil organic matter in comparison to unfertilized soil was studied in particle-size fractions using elemental (C and N) analyses and pyrolysis-field ionization mass spectrometry. Distinct differences in C and N concentrations and distribution and in the quality of organic matter between the size fractions and the fertilization treatments were observed. Clay-associated C and N were relatively higher in the unfertilized treatment, whereas the application of farmyard manure preferentially increased soil organic matter associated with the fine and medium silt fractions. Pyrolysis-field ionization mass spectrometry of soil fractions 〈20 μm showed increasing values for lignin monomers and dimers and fatty acids with larger equivalent diameters, whereas the proportion of N compounds, mono- and polysaccharides and phenolics decreased in the larger size fractions. Sand fractions were particularly rich in lignin fragments, mono- and polysaccharides, and alkanes/alkenes. These relationships seemed to be independent of management practices. In the same size fractions of the different treatments, however, a higher relative abundance of N-compounds, mono- and polysaccharides, phenolics, lignin monomers, and alkanes/alkenes was observed in the unfertilized variant. Lignin dimers and fatty acids were more abundant in the farmyard manure treatment. Both trends together imply that soil enrichment in organic matter due to the application of farmyard manure largely reflects an increase in lignin building blocks and partly reflects an increase in lipids such as fatty acids in the silt fractions. Therefore these constituents are of particular importance in assessing the positive effects of farmyard manure on soil fertility.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 351 (1970), S. 41-67 
    ISSN: 1432-2307
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The finer capillary branches of the liver lymph vessel system become unfolded by ligatures of the liver hilus lymph vessels. The experiments were performed in rabbits and rats. The liver lobules do not contain lymphatics. In the Glisson fields often several lymphatics can be demonstrated. The lymphatics are characterized by a flat endothelium, lacking of endothelial pores and basal membrane, by overlapping cell borders and by small papillary protrusions of the endothelium. The endothelial cells are fixated in a dense network of fine filaments. Strong lymphostasis or cholestasis lead to bursting of the intercellular spaces and to open junctions between capillary lumen and interstitial tissue. An exclusive experimental lymphostasis of the liver induces only short time parenchyma alterations. The lymphostatic oedema decreases the liver storing capacity for tantalum powder. Combination of lymphostasis with other stresses like cholestasis lead to more severe alterations than pure lymphostasis or cholestasis. 2–3 months after lymphostasis plus cholestasis intensive cirrhotic transformation of rat liver parenchyma can be noticed. The importance of the factor lymphostasis of the liver is discussed for human pathology.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Heavy density fractions of soil contain organic matter tightly bound to the surface of soil minerals. The chemical composition and ecological meaning of non-metabolic decomposition products and microbial metabolites in organic–mineral bonds is poorly understood. Therefore, we investigated the heavy fraction (density 〉 2 g cm–3) from the topsoil of a Gleysol (Bainsville, Ottawa, Canada). It accounted for 952 g kg–1 of soil and contained 19 g kg–1 of organic C. Pyrolysis-field ionization mass spectra showed intensive signals of carbohydrates, and phenols and lignin monomers, alkylaromatics (mostly aromatic) N-containing compounds, and peptides. These classes of compound have been proposed as structural building blocks of soil organic matter. In comparison, the light fraction (density 〉 2 g cm–3) was richer in lignin dimers, lipids, sterols, suberin and fatty acids which clearly indicate residues of plants and biota. To confirm the composition and stability of mineral-bound organic matter, we also investigated the heavy fraction (density 〉 2.2 g cm–3) from clay-, silt- and sand-sized separates of the topsoil of a Chernozem (Bad Lauchstädt, Germany). These heavy size separates differed in their mass spectra but were generally characterized by volatilization maxima of alkylaromatics, lipids and sterols at about 500°C. We think that the observed high-temperature volatilization of these structural building blocks of soil organic matter is indicative of the organic–mineral bonds. Some unexpected low-temperature volatilization of carbohydrates, N-containing compounds, peptides, and phenols and lignin monomers was assigned to hot-water-extractable organic matter which accounted for 7–27% of the carbon and nitrogen in the heavy fractions. As this material is known to be mineralizable, our study indicates that these constituents of the heavy density fractions are degradable by micro-organisms and involved in the turnover of soil organic matter.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In-source pyrolysis field ionization mass spectrometry (Py-FIMS) and Curie–point pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) have been applied to the characterization of whole soils methylated off–line and on–line by two methylation reagents. Samples of a gleysolic Ap–horizon and a podzolic Bh horizon (Corg concentrations 2–3%) were investigated by conventional on–line and developed off–line methylation with tetramethylammonium hydroxide (TMAH) and by off–line methylation with diazomethane. For the first method, the soils were dried, milled and pretreated with TMAH for 10 min at 250°C at ambient pressure outside the pyrolyzers. For the second method, the dried and milled soils were methylated with an ether solution of diazomethane for 12 h at room temperature (∼20°C). Pyrolysis methylation with TMAH enabled aliphatic C2–C39 monocarboxylic acid methyl esters, C4–C30 dicarboxylic acid dimethyl esters and benzenecarboxylic acid methyl esters to be detected. Methoxybenzenes from phenols, benzenediols and benzenetriols, methoxybenzenecarboxylic acid methyl esters from phenolic acids and furancarboxylic acid methyl esters from carbohydrates were also identified. Nitrogen–containing compounds in soil organic matter were obtained as N,N–dimethylamides. Using diazomethane as methylation reagent, distinct Py-FIMS signals were observed for aliphatic C2–C32 monocarboxylic acid methyl esters and C3–C24 dicarboxylic acid dimethyl esters. Additionally, methoxybenzenes originating from lignins, methoxybenzenecarboxylic acid methyl esters from phenolic acids and N,N–dimethylamides from amides were detected. The more acid podzolic Bh horizon showed higher relative intensities for dicarboxylic acid dimethyl esters and methylated phenolic acids compared to the gleysolic Ap horizon. Similarly, benzenecarboxylic acids are connected mainly by ester linkages to the macromolecular network of soil organic matter. Both methylation procedures support conventional Py-FIMS and Py-GC/MS and give valuable additional information on the occurrence of aliphatic and aromatic carboxylic acids, substituted phenols, benzenediols, benzenetriols, phenolic acids and amides in soil organic matter.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In an acid soil, amounts or organic carbon resistant to peroxidation with hydrogen peroxide were strongly related to the proportions of expandable phyllosilicate (vermiculite, smectite) in the clay fraction, as measured by its K2O content and cation exchange capacity. This was taken to indicate that a substantial part of the organic matter resistant to oxidation was interlayered. The organic compounds in the clay-organic matter complexes were identified by Pyrolysis Field Ionization Mass Spectrometry (Py-FIMS).Alkyl-aromatics as well as carbohydrates, phenols, lignins, lipids and N-compounds were found in the C-horizon sample, whereas mainly alkyl-aromatics and N-compounds, more resistant to chemical oxidation, were associated with the A1 and Bw fine-clay fraction. This was interpreted as being due either to the evolution of the clay-associated compounds paralleling the mineralogical transformations, or to the selective adsorption of the more stable components.
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