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- Cheng, Y.F., et al.
(författare)
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TEM study of the early stages of the precipitation process in strip-cast Al3003 alloys
- 1992
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Ingår i: Journal of Materials Research. - 0884-2914. ; 7, s. 3235-3241
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Tidskriftsartikel (refereegranskat)abstract
- The precipitation behavior, especially the early nucleation stages, of the industrial strip-cast Al3003 alloys was investigated by using transmission electron microscopy (TEM). An icosahedral quasicrystalline phase was found as secondary particles in these strip-cast alloys after heat treatment for a few seconds. Three different nucleation paths are proposed based on the TEM observations. They have the same origin, viz. (Mn, Fe)-containing Mackay icosahedra, and are governed by the composition of alloys, especially the Mn and Si content.
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| 2. |
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| 3. |
- Schwab, U E, et al.
(författare)
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Increased adherence of Staphylococcus aureus from cystic fibrosis lungs to airway epithelial cells.
- 1993
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Ingår i: The American review of respiratory disease. - 0003-0805. ; 148:2, s. 365-9
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Tidskriftsartikel (refereegranskat)abstract
- Airway colonization by Staphylococcus aureus is a frequent feature of cystic fibrosis (CF). To assess the pathogenesis of selective colonization with this organism, we compared the capacity of S. aureus isolated from the respiratory tract of CF and non-CF patients to adhere to epithelial cells from the upper and lower airways of CF and control subjects. Bacterial adherence to bronchial epithelial cell lines was significantly greater for CF than for non-CF isolates (p < 0.001). Of 17 CF S. aureus isolates 12 adhered at a level > 1 bacterium per cell; this was true for only 1 of 14 non-CF isolates. CF S. aureus isolates also bound more avidly than non-CF isolates to ciliated (p < 0.05) and squamous nasal cells (p < 0.02) and buccal epithelial cells (p < 0.005) freshly harvested by scraping. Each S. aureus isolate bound with equal avidity to epithelial cells from CF patients and healthy individuals. Adherence was not related to sex, age, severity of pulmonary disease, presence of other microorganisms in the airways, or genotype of the CF hosts. Binding of S. aureus was blocked by proteinase treatment of organisms, suggesting that adherence is mediated by one or more peptide adhesins. We propose that the high prevalence of adherent S. aureus is due either to selection of adherent strains by CF airways or to induction of an adherent phenotype by factors residing at the CF airways surface.
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