Absorption morphological changes

At least part of the impairment of iron absorption in riboflavin deficiency is a result of morphological changes in the intestinal mucosa, with hyperproliferation, an increased rate of enterocyte transit along the villi and a reduced number of (longer) villi and deeper crypts (Williams et al., 1996). 

To understand the interaction of LiBr with the copolyurethanes and the resulting morphological changes, nonextracted samples of PEUU 700 were studied, because this copolyurethane exhibited the largest variation in water absorption and tensile strength as a function of salt concentration. 

Various approaches have been described in the literature for the characterization of carbon-supported metal catalysts. The catalysts are usually analyzed before and after (postmortem) their electrochemical operation with conventional ex situ techniques such as x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive x-ray analysis (EDX), x-ray photoelectron spectroscopy (XPS), and x-ray absorption spectroscopy (XAS). Although ex situ analysis provides an important starting point in catalyst characterization, one must keep in mind that significant morphological changes may occur under the operational conditions. It is thus vitally important... 

This shows that the surface deterioration advances approximately in proportion to exposure time, and that the progress of deterioration depends upon the surface oxygen concentration and the rate constant of photo-oxidation, though it depends,of course, linearly on the intensity of incident light. The surface deterioration can be observed in IR absorption spectra and in the morphological change in SEM, and further in the change of material properties. 

Bemstam et al. (2002) measured percutaneous absorption of As(lll) and As(V) in vitro using artificial human skin. The permeability constant (K ) for As(V) and As(lll) were determined from this study as 4.3 x 10 cm/h and 10.1 x 10 cm/h respectively. As(lll) at exposure doses as low as 10 /zg/L could cause significant morphological changes, disruption of cell membrane and inhibition of deoxyribonucleic acid (DNA) and protein syntheses. The authors noted that concentrations of tri- or pentavalent arsenic at levels above 100 /zg/L in showering- or hand-washing waters could manifest harmful effects. 

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