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- Lawniczak-Jablonska, Krystyna, et al.
(författare)
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Structural and magnetic properties of the molecular beam epitaxy grown MnSb layers on GaAs substrates
- 2009
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 106:8
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Tidskriftsartikel (refereegranskat)abstract
- The structural and magnetic properties of MnSb layers grown on two differently oriented GaAs substrates are reported. The MnSb compounds grow nonhomogenously both on GaAs (111) B and on GaAs (100) substrates. In x-ray diffraction studies the formation of two epitaxial domains is observed depending on the crystallographic orientation of the substrate. The observed diffusion of Ga atoms from the substrate to the layers results in the formation of an additional Mn-rich cubic phase of GaMnSb. In the case of the (100) oriented substrate, the diffusion of Mn into the substrate was additionally found. Traces of other phases were also noticed. The complex morphology of the layers is found to influence their magnetic properties. Magnetic force microscopy images revealed an inhomogenous distribution of the magnetic force gradient on the surface and the formation of magnetic domains in the samples. X-ray absorption studies of the chemical bonding and local atomic structure around Mn atoms confirmed high structural and chemical disorder in the samples. The chemical bonding of the dominating fraction of Mn atoms is found, however, similar to that in the reference MnSb powder. The x-ray magnetic circular dichroism measurements reveal an enhanced orbital moment and a reduced spin moment, which is most likely caused by the presence of different phases and a Mn-rich surface in the investigated samples.
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| 2. |
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| 3. |
- Lienenklaus, Stefan, et al.
(författare)
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Novel reporter mouse reveals constitutive and inflammatory expression of IFN-beta in vivo.
- 2009
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 183:5, s. 3229-3236
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Tidskriftsartikel (refereegranskat)abstract
- Type I IFN is a major player in innate and adaptive immune responses. Besides, it is involved in organogenesis and tumor development. Generally, IFN responses are amplified by an autocrine loop with IFN-beta as the priming cytokine. However, due to the lack of sensitive detection systems, where and how type I IFN is produced in vivo is still poorly understood. In this study, we describe a luciferase reporter mouse, which allows tracking of IFN-beta gene induction in vivo. Using this reporter mouse, we reveal strong tissue-specific induction of IFN-beta following infection with influenza or La Crosse virus. Importantly, this reporter mouse also allowed us to visualize that IFN-beta is expressed constitutively in several tissues. As suggested before, low amounts of constitutively produced IFN might maintain immune cells in an activated state ready for a timely response to pathogens. Interestingly, thymic epithelial cells were the major source of IFN-beta under noninflammatory conditions. This relatively high constitutive expression was controlled by the NF Aire and might influence induction of tolerance or T cell development.
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| 4. |
- Łyszkiewicz, Marcin, et al.
(författare)
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SIGN-R1+MHC II+ cells of the splenic marginal zone : a novel type of resident dendritic cells
- 2011
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Ingår i: Journal of Leukocyte Biology. - : Oxford University Press (OUP). - 0741-5400 .- 1938-3673. ; 89:4, s. 607-615
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Tidskriftsartikel (refereegranskat)abstract
- In the spleen, the MZ forms an interface between red and white pulp. Its major function is to trap blood-borne antigens and to reorient them to APCs and lymphocytes. SIGN-R1(+) cells are of the MZ inherent cell population, which for a long time, have been considered as macrophages. We now show that one subpopulation of SIGN-R1(+) cells that express MHC II molecules should be considered as a resident DC. Histological analysis indicated that SIGN-R1(+) cells have dendritic-like protrusions extending into T and B cell areas. Flow cytometry analysis revealed an expression profile of adhesion, costimulatory, and MHC molecules similar to cDCs but distinct from macrophages. Most importantly, SIGN-R1(+)MHC(+) cells were able to present antigen to naïve CD4 T cells, as well as to cross-present soluble, particulate antigens secreted by Listeria monocytogenes to CD8 T cells in vitro and in vivo. Our experiments identified SIGN-R1(+)MHC II(+) cells as professional APCs and indicate their nature as splenic resident DCs.
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