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  • 1995-1999  (3)
  • 1970-1974  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    A new approach for determining effective soil hydraulic functions (1998)
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 49 (1998), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: We investigated the possibility of inferring effective hydraulic properties of soil from the structure of the pore space. The aim was to identify structural properties, which are essential for water flow, so that physical experiments may be replaced by direct morphological measurements. The pore structure was investigated in three dimensions by serial sections through impregnated samples. The complex geometry of pore space was quantified in terms of two characteristics: pore-size distribution and pore connectivity. Only pores larger than 0.04 mm were considered. The results were used as input parameters for a pore-scale network model. The main desorption branch of the soil-water characteristic and the corresponding hydraulic conductivity function of the network model were calculated by numerical simulation. The simulation results, which are exclusively based on morphological investigations, were compared with independently measured results from a multi-step outflow experiment. This approach was demonstrated for two centrasting soil materials: the A and B horizons of a silty agricultural soil. The simulations were close to the experimental data, except for the absolute values of the hydraulic conductivity. The pore-size distribution and pore connectivity govern the shape of hydraulic functions and the applied morphometric methods are suitable for predicting essential characteristics of hydraulic soil properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2389.1998.4940547.x
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  • 2
    Electronic Resource
    Electronic Resource
    Morphological determination of pore connectivity as a function of pore size using serial sections (1997)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of soil science 48 (1997), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The geometry of pore space in soil is considered to be the key in understanding transport of water, gas and solute. However, a quantitative and explicit characterization, by means of a physical interpretation, is difficult because of the geometric complexity of soil structure.Pores larger than 40 μm within two soil horizons have been analysed morphologically on 3-dimensional digital representations of the pore space obtained by serial sections through impregnated specimens. The Euler-Poincaré characteristic has been determined as an index of connectivity in three dimensions. The pore connectivity is quantified as a function of the minimum pore diameter considered leading to a connectivity function of the pore space. Different pore size classes were distinguished using 3-dimensional erosion and dilation. The connectivity function turned out to differentiate between two soil materials. The pore space in an upper Ah horizon is intensely connected through pores between 40 and 100 μm, in contrast to the pore space in the AhBv beneath it. The morphological pore-size distributions were compared to the pore-size distribution obtained by water retention measurements. The discrepancy between these different methods corresponds to the expectation due to pore connectivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.1997.tb00203.x
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Der Formenzyklus der Uterindriisen der Stute im Vergleich zu dem anderer Säugetiere und des Menschen (1973)
    Oxford, UK : Blackwell Publishing Ltd
    Anatomia, histologia, embryologia 2 (1973), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Die Gestalt der Uterindrüsen der Stute wird nadi Mazeration in Eisessig und nach Prepäration in Glycerin räumlich dargestellt. Ihr zyklusabhängiger Formenwandel sowie das für das Stutenendometrium charakteristische hohe Stratum subglandulare werden diskutiert. In einer vergleichenden Betrachtung wird die Drüsenhyperplasie im Postoestrum bei alien Haussäugetieren und beim Menschen herausgestellt. Bei der Maus liegt dagegen eine Drüsenhypertrophie im Oestrum vor.〈section xml:id="abs1-2"〉〈title type="main"〉SummaryCyclic changes in the shape of the mare's uterine glands compared with those of other mammals and manAfter maceration in glacial acetic acid and dissection under glycerin the shape of the mare's uterine glands is demonstrated three-dimensionally. Their changes in shape and size, related to the estrous cycle, and the thick subglandular layer, characteristic of the mare's endometrium, are discussed. Glandular hyperplasia occurs in the postestrous period in all domestic mammals and in man. In the mouse however there is glandular hypertrophy during estrus.〈section xml:id="abs1-3"〉〈title type="main"〉RésuméLes changements de forme cycliques des glandes utérines de la Jument, comparés à ceux des autres Mammifères et de l'HommeAprès macération dans l'acide acétique glacial et préparation dans la glycérine, la forme des glandes utérines de la Jument a été représentée dans l'espace. Leurs changements de forme, liés au cycle, ainsi que le Stratum subglandulare, élevé, caractéristique de l'endomètre de la Jument, sont discutés. Dans une étude comparée, l'hyperplasie glandulaire au Postoestrus est mise en évidence chez tous les Mammifères domestiques et chez l'Homme. Chez la Souris, par contre, c'est à l'Oestrus qu'on observe une hypertrophic glandulaire.〈section xml:id="abs1-4"〉〈title type="main"〉ResumenLos cambios ciclicos en la forma de las glándulas uterinas de la yegua en comparación con los de otros mamíferos y del hombreMediante la maceración en ácido acético glacial y la preparación en glicerina, se demuestran las glándulas uterinas en forma tridimensional. Se discute su cambio cíclico y su capa subglandular (Stratum subglandulare) característica para el endometrio de la yegua. Un estudio comparado de los animates domésticos y del hombre destaca la hiperplasia de las glándulas durante el postestro. En el ratón, al contrario, la hipertrofia glandular se encuentra durante el estro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0264.1973.tb00407.x
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Lead-207 NMR: a novel probe for the study of calcium-binding proteins (1996)
    Springer
    JBIC 1 (1996), S. 39-48 
    Details
    ISSN: 1432-1327
    Keywords: Key words207Pb NMR ; Calmodulin ; Parvalbumin ; Helix-loop-helix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract  The high-affinity Ca2+–binding sites of carp (pI 4.25) and pike (pI 5.0) parvalbumins, as well as those of mammalian calmodulin (CaM) and its C-terminal tryptic half-molecule (TR2C), were analyzed by 207Pb NMR spectroscopy. For the parvalbumins, two 207Pb signals were observed ranging in chemical shift from ≈750 to ≈1260 ppm downfield of aqueous Pb(NO3)2, corresponding to 207Pb2+ bound to the two high-affinity helix-loop-helix Ca2+–binding sites in each of these proteins. Four 207Pb signals, which fall in the same chemical shift window, could be discerned for CaM. Experiments on TR2C permitted the assignment of each signal as due to 207Pb2+ occupying a helix-loop-helix site in either the N- or the C-lobe of the intact protein. 207Pb and 1H NMR titration studies on CaM provided evidence that Pb2+ binding to all four sites occurs simultaneously, in contrast to the behavior of this protein in the presence of Ca2+. Titrations of the 207Pb2+–forms of CaM and TR2C with the antipsychotic drug trifluoperazine demonstrated that drug binding to the exposed hydrophobic surfaces in CaM causes substantial conformational changes and proceeds in a sequential manner – first the C-lobe and subsequently the N-lobe. Finally, the field dependence of CaM-bound 207Pb signals was examined. The 207Pb signal linewidths exhibited a sharp dependence on the square of the external magnetic field, a trend characteristic of relaxation via chemical shift anisotropy. Relaxation studies on TR2C demonstrated that chemical exchange also contributes to the observed linewidths. The large chemical shift dispersion observed for the 207Pb signals of the three proteins studied here illustrates the remarkable sensitivity of this parameter to subtle differences in the chemical environment of the protein-bound 207Pb nucleus. To our knowledge, the data presented in this article comprise the first ever published example of the application of 207Pb NMR spectroscopy to metalloproteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007750050021
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    Paper (German National Licenses)
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