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- Hunter Dunn, Jonathan, et al.
(författare)
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Vanishing Magnetic Interactions in Ferromagnetic Thin Films
- 2005
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Ingår i: PHYSICAL REVIEW LETTERS. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 94:21, s. 217202-
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Tidskriftsartikel (refereegranskat)abstract
- We have used element-specific hysteresis measurements, based on the x-ray magnetic circular dichroism technique, to investigate magnetic trilayer structures composed of Fe and Ni layers. Within a critical regime we have discovered a class of structures in which the exchange interaction, the mechanism responsible for the macroscopic magnetism, can become vanishingly small. The experimental observations are supported by first principles theory and are explained as arising from a cancellation of several competing magnetic interactions. Hence, we have discovered a system with a novel exchange interaction between magnetic layers in direct contact that replaces the conventional exchange interaction in ferromagnets.
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| 2. |
- Svensson, Per, et al.
(författare)
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Gene array identification of Ipf1/Pdx1(-/-) regulated genes in pancreatic progenitor cells
- 2007
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Ingår i: BMC Developmental Biology. - : Springer Science and Business Media LLC. - 1471-213X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: The homeodomain transcription factor IPF1/PDX1 exerts a dual role in the pancreas; Ipf1/Pdx1 global null mutants fail to develop a pancreas whereas conditional inactivation of Ipf1/Pdx1 in beta-cells leads to impaired beta-cell function and diabetes. Although several putative target genes have been linked to the beta-cell function of Ipf1/Pdx1, relatively little is known with respect to genes regulated by IPF1/PDX1 in early pancreatic progenitor cells. Results: Microarray analyses identified a total of III genes that were differentially expressed in e10.5 pancreatic buds of Ipf1/Pdx1(-/-) embryos. The expression of one of these, Spondin 1, which encodes an extracellular matrix protein, has not previously been described in the pancreas. Quantitative real-time RT-PCR analyses and immunohistochemical analyses also revealed that the expression of FgfR2IIIb, that encodes the receptor for FGF10, was down-regulated in Ipf1/Pdx1(-/-) pancreatic progenitor cells. Conclusion: This microarray analysis has identified a number of candidate genes that are differentially expressed in Ipf1/Pdx1(-/-) pancreatic buds. Several of the differentially expressed genes were known to be important for pancreatic progenitor cell proliferation and differentiation whereas others have not previously been associated with pancreatic development.
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| 3. |
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