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- Li, C-H., et al.
(författare)
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A lattice resolution study of the martensitic transformation of small iron particles in a copper matrix
- 1985
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Ingår i: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 33:2, s. 317-328
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Tidskriftsartikel (refereegranskat)abstract
- The martensitic transformation of small, fully coherent, gamma iron precipitates in an epsilon copper matrix, brought about by the bombardment of thin foils with argon ions, has been studied using lattice fringe imaging. It is found, in general, that only partial transformation of individual particles occurs, this corresponding to a simple homogeneous shear (a Bain strain). In addition, the transformation is limited to particles located within about two particle diameters of the foil surface. It is established that the mere presence of a Frank (or Shockley) loop in a particle, due to the bombardment, is insufficient to trigger the transformation. The implications of this result are discussed with reference to bulk martensite. In the present case, it is concluded that transformation may simply initiate at sites of local decohesion or microslip at the matrix/particle boundaries brought about by vacancy condensation following ion bombardment, these sites being most effective in the vicinity of free surfaces
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| 2. |
- Rozengurt, E., et al.
(författare)
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Signal transduction in mitogenesis : further evidence for multiple pathways
- 1988
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Ingår i: Cold Spring Harbor Symposia on Quantitative Biology. - : Cold Spring Harbor Laboratory Press (CSHL). - 0091-7451 .- 1943-4456. ; 53, s. 945-954
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Tidskriftsartikel (refereegranskat)abstract
- This extract was created in the absence of an abstract.ExcerptGrowth factors are implicated in a wide variety of physiological and pathological processes, including embryogenesis, hematopoiesis, wound healing, immune responses, atherosclerosis, and neoplasis (Evered et al. 1985; Sporn and Roberts 1986). An important link between growth factors and their receptors and oncogene products has also been established (Heldin and Westermark 1984; Weinstein 1987). Thus, the elucidation of the mechanism of action of growth factors has emerged as one of the fundamental problems in biology and may prove crucial for understanding the unrestrained proliferation of cancer cells.Many studis of growth factors have used cultured fibroblasts, such as 3T3 cells, as a model system. These cells cease to proliferate when they deplete the medium of its growth-promoting activity. Such quiescent cells can be stimulated to reinitiate DNA synthesis and cell division either by replenishing the medium with fresh serum or by the addition of growth factors or pharmacological agents in serum-free...
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