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  • 1
    Electronic Resource
    Electronic Resource
    Nitrogen transformation in arable soils of North-West Germany during the cereal growing season (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 179-183 
    Details
    ISSN: 1432-0789
    Keywords: Key words Microbial N ; Immobilization ; Remobilization ; NH4+ fixation ; Exchangeable NH4+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In 1991, field experiments on loess (with winter wheat) and sandy soils (with summer barley) were conducted to study N dynamics in the microbial biomass and non-exchangeable NH4 +. The measurements showed a mass change in microbial N, with a maximum increase of 100 kg N ha–1 30 cm–1 from March to July in the loess soil, and a change for only 1 month (May) in the sandy soil. Plots treated with conventional levels of N fertilizer (213 kg N ha–1 on a loess soil to winter wheat and 130 kg ha–1 on the sandy soil to summer barley), reduced levels of N (83% and 62% of the conventional N application), or no N showed no consistent fertilizer N effect on microbial biomass N. From March to July, non-exchangeable NH4 + in loess soils under winter wheat decreased by 110 kg N ha–1 30 cm–1 in conventionally fertilized plots and by 200 kg N ha–1 30 cm–1 in a plot with no N fertilizer. After harvest, the pool of non-exchangeable NH4 + increased due to increasing mineral N concentrations in the soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384452
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effects of ischaemia and preservation on the ultrastructure of the bronchiolar epithelium (1996)
    Springer
    Virchows Archiv 429 (1996), S. 109-118 
    Details
    ISSN: 1432-2307
    Keywords: Lung-transplantation pathology ; Bronchi-epithelium ; Ischaemia ; Mitochondrial swelling ; Scanning electron microscopy ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In ten cases of clinical human single-lung transplantation, the nontransplanted Euro-Collins-preserved contralateral lungs were examined using electron microscopy to determine the effects of ischaemia on the bronchiolar epithelium. Existing structural damage at the time of transplantation was characterized using this approach, and nine nonpreserved canine single lungs were also investigated to identify the impact of ischaemia. The study revealed a significant correlation between the duration of ischaemia and the mitochondrial surface-to-volume ratio, which can serve as a morphometric criterion for mitochondrial damage, in canine lungs. However, this correlation was not found in the human donor lungs. Further examination of human donor lungs showed slight to moderate damage to the endoplasmic reticulum and nuclear chromatin. In addition, various degrees of damage to mitochondrial structure, ranging from inconspicuous to severe, were found. The mitochondrial surface-to-volume ratio can be considered to be a suitable criterion for the quantification of ischaemic damage of the bronchiolar epithelium under experimental conditions. Ultrastructural analysis of human donor lungs revealed intact bronchiolar epithelial cell structures at the time of transplantation, reflecting adequate organ preservation with Euro-Collins solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192433
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The surface to volume ratio of mitochondria, a suitable parameter for evaluating mitochondrial swelling (1990)
    Springer
    Virchows Archiv 416 (1990), S. 305-315 
    Details
    ISSN: 1432-2307
    Keywords: Myocardial ultrastructure ; Mitochondrial swelling ; Stereology ; Correlations of structural parameters ; Cardiac arrest and global ischaemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cellular changes occuring in the left ventricular myocardium during ischaemia after different methods of cardiac arrest have been evaluated by morphological and morphometric parameters: volume densities of mitochondria (VVMi), sarcoplasm (VVSp), myofibrils (VVMf), surface densities of mitochondria (SVMi). The surface to volume ratio of mitochondria (SVratioMi) has been used as an independent parameter of mitochondrial swelling. Since ischaemic swelling of myocardial cells increases the volume of the reference space and ischaemic swelling of mitochondria decreases the free sarcoplasm, VVMi and VVSp cannot be considered as reliable indicators of the degree of oedema. SVMi/VVMf remains nearly constant after different forms of cardiac arrest, demonstrating the integrity of mitochondrial outer membranes. The inverse linear ratio between SVratioMi and the mean mitochondrial volume indicates that the increase in mitochondrial volume is achieved by surface smoothing. Loss of matrix structure and fragmentation of cristae occur at an SVratioMi of about 5.8, cristolysis at 5.5 to 5.6 and amorphous matrix densities at an SVratioMi of less than 5.5 μm2/μm3. The SVratioMi is a suitable parameter for evaluating mitochondrial swelling both at the onset and during global myocardial ischaemia, independent of the method of cardiac arrest used. It serves as an indicator of the state of structural preservation of mitochondria during ischaemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01605291
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Nitrogen transformation in arable soils of North-West Germany during the cereal growing season (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 179-183 
    Details
    ISSN: 1432-0789
    Keywords: Microbial N ; Immobilization ; Remobilization ; NH inf4 sup+ fixation ; Exchangeable NH inf4 sup+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In 1991, field experiments on loess (with winter wheat) and sandy soils (with summer barley) were conducted to study N dynamics in the microbial biomass and non-exchangeable NH inf4 sup+ . The measurements showed a mass change in microbial N, with a maximum increase of 100 kg N ha-1 30 cm-1 from March to July in the loess soil, and a change for only 1 month (May) in the sandy soil. Plots treated with conventional levels of N fertilizer (213 kg N ha-1 on a loess soil to winter wheat and 130 kg ha-1 on the sandy soil to summer barley), reduced levels of N (83% and 62% of the conventional N application), or no N showed no consistent fertilizer N effect on microbial biomass N. From March to July, non-exchangeable NH inf4 sup+ in loess soils under winter wheat decreased by 110 kg N ha-1 30 cm-1 in conventionally fertilized plots and by 200 kg N ha-1 30 cm-1 in a plot with no N fertilizer. After harvest, the pool of non-exchangeable NH inf4 sup+ increased due to increasing mineral N concentrations in the soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384452
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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