ABSTRACT
For the assessment of soil structural stability against hydraulic stress, wet sieving or constant head permeability tests are typically used but rather limited in their intrinsic information value. The multiple applications of several tests is the only possibility to assess important processes and mechanisms during soil aggregate breakdown, e.g. the influences of soil fragment release or differential swelling on the porous systems of soils or soil aggregate columns. Consequently, the development of new techniques for a faster and more detailed wet aggregate stability assessment is required. (1)H nuclear magnetic resonance relaxometry ((1)H-NMR relaxometry) might provide these requirements because it has already been successfully applied on soils. We evaluated the potential of (1)H-NMR relaxometry for the assessment of wet aggregate stability of soils, with more detailed information on occurring mechanisms at the same time. Therefore, we conducted single wet sieving and constant head permeability tests on untreated and 1% polyacrylic acid-treated soil aggregates of different textures and organic matter contents, subsequently measured by (1)H-NMR relaxometry after percolation. The stability of the soil aggregates were mainly depending on their organic matter contents and the type of aggregate stabilization, whereby additional effects of clay swelling on the measured wet aggregate stability were identified by the transverse relaxation time (T2) distributions. Regression analyses showed that only the percentage of water stable aggregates could be determined accurately from percolated soil aggregate columns by (1)H-NMR relaxometry measurements. (1)H-NMR relaxometry seems a promising technique for wet aggregate stability measurements but should be further developed for nonpercolated aggregate columns and real soil samples.
ABSTRACT
IgE has two types of receptors: high affinity RFc sigma I and low affinity RFc sigma II. The latter may be studied by flow cytometry by the membrane marker CD23 (mCD23), expressed on B and T cells, monocytes, macrophages, Langerhans cells, eosinophils and platelets. Soluble CD23 (sCD23) corresponds with the extracellular C terminal domain of mCD23. The aim of the study was to search for a correlation between the levels of mCD23 and sCD23, comparatively with IgE, eosinophils, eosinophil cationic protein (ECP) and to the cytokines IL2, IL4 and IL6. 78 patients took part in the study, divided into two groups: Group 1 = atopics (n = 61); Group 2 = controls (n = 17). The majority presented with rhinitis, asthma, atopic dermatitis isolated or associated. The results showed a highly significant correlation between mCD23 and sCD23 compared with the control group. There was also a statistically significant increase for mCD23, sCD23, cytokines IL2, IL4 and IL6, mediator ECP in parallel with eosinophils and total IgE. This study confirms amongst other things the rise in IL4 in atopy and the correlation between the level of ECP and that of eosinophils, and that there is an overall correlation between mCD23 and sCD23.
