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  • Author or Editor: C. S. Müller x
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The effect of a pure endoxylanase (Xyn2) and endoglucanase (EgII) from Trichoderma reesei on bread flour quality were compared to a commercial endoxylanase from Aspergillus niger (Com-xyl) and a cellulase-xylanase cocktail from T. reesei (Cel-xyl). Effects of these enzymes on dough quality, bread weight, height and crumb softness were analysed. Results obtained during commercial-scale baking tests often differed from those obtained during laboratory-scale tests; indicating that results from laboratory-scale baking tests cannot be extrapolated to commercialscale bread production. Low levels of endoxylanase activity benefited bread height and volume without affecting slice brightness in commercial-scale tests. The addition of endoglucanases and α-amylases can also be advantageous resulting in less endoxylanase activity required to obtain similar results.

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Potassium hexacyanoferrate(II) trihydrate, K4Fe(CN)6·3H2O, was heated under controlled conditions of mass and rate in a derivatograph in the presence of oxygen. The heating was stopped at different temperatures and Mössbauer spectra and X-ray diffractograms were taken on the quenched material at room temperature. The reaction pathway was studied in this way and the advantages and drawbacks of each of the techniques are described. At different stages of the thermal process we were able to show the presence of K4Fe(CN)6,α-Fe2O3, Fe3O4, Fe3C, Fe, FeO, KFeO2,Β-FeOOH, KOCN, K2CO3 and KCN.

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Abstract  

The accuracy of dual energy X-ray absorptiometry (DEXA) for measurement of bone mass carried out by quantitative digital radiography (Hologic Inc.) was compared to results with neutron activation analysis (NAA) on 106 subjects. The accuracy with DEXA was further investigated by measurements on aluminium samples of known composition. DEXA measured 4 lumbar vertebrae by spine scan. The central third of the skeleton also was measured by whole body scan to obtain data on the same large part of the skeleton as measured by NAA. Results suggested that DEXA spine scans were more reliable than whole body scans. In addition, the measurement of total mineral content (BMC) was more reliable than the normalization of BMC to bone surface area (BMC/Area) or bone mineral density (BDM). Since the proportion of bone below detection would increase with development of osteoporosis, with osteoporosis the BMC would be increasingly underestimated, but to only a small extent, while the BMD would be more significantly overestimated.

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The phylogenetic relationship among species may influence the mechanisms controlling local community assembly in ecological time. We analyzed the degree of recurrence of phylogenetic structure patterns in woody plant communities distributed along grassland-forest ecotones, across different vegetation types in southern Brazil, and the effect of phylogenetic pool size used to assess such patterns. Species frequency in quadrats distributed along grassland-forest ecotones was surveyed in different phytogeographic regions, where forests tend to expand over grasslands. We used principal coordinates of phylogenetic structure (PCPS) to evaluate the structure within vegetation quadrats divided into three habitat categories: grassland, forest edge and forest interior. Furthermore, phylogenetic structure measures were computed using different phylogenetic pool sizes. Our analyses showed consistent patterns in relation to habitat categories and to different phylogenetic pool sizes. Basal clades of angiosperms were associated with forest areas, while late-divergence clades were associated with grasslands. These results suggest that grasslands act as phylogenetic habitat filters to forest woody species, independently of species composition at each site and the phylogenetic pool. Rosanae and Asteranae act as vanguards of forest expansion over grasslands, while Magnolianae species tend to be restricted to forest. Our results shed light on the organization of ecological systems, providing evidence of recurrent phylogenetic structure patterns in ecotone plant communities at regional scale.

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