| 41. |
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| 42. |
- Mikhailov, T. N., et al.
(författare)
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Recombination dynamics in heterostructures with two planar arrays of II-VI quantum dots
- 2016
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Ingår i: 3RD INTERNATIONAL SCHOOL AND CONFERENCE ON OPTOELECTRONICS, PHOTONICS, ENGINEERING AND NANOSTRUCTURES (SAINT PETERSBURG OPEN 2016). - : IOP PUBLISHING LTD.
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Konferensbidrag (refereegranskat)abstract
- We present time-resolved photoluminescence studies of epitaxial heterostructures with two arrays of Cd(Zn)Se/ZnSe quantum dots (QDs), which are formed by the successive insertion of CdSe fractional monolayers of different nominal thicknesses into a ZnSe matrix. Our data are suggestive of the appearance of effective channels of the energy transfer from the insertion comprising the array with smaller QDs, emitting at higher energy, towards the array with larger QDs, emitting at lower energy. The effect of dark excitons on characteristic times of radiative recombination is discussed.
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| 43. |
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| 44. |
- Song, J., et al.
(författare)
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Extracellular matrix of secondary lymphoid organs impacts on B-cell fate and survival
- 2013
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 110:31
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Tidskriftsartikel (refereegranskat)abstract
- We describe a unique extracellular matrix (ECM) niche in the spleen, the marginal zone (MZ), characterized by the basement membrane glycoproteins, laminin alpha 5 and agrin, that promotes formation of a specialized population of MZ B lymphocytes that respond rapidly to blood-borne antigens. Mice with reduced laminin alpha 5 expression show reduced MZ B cells and increased numbers of newly formed (NF) transitional B cells that migrate from the bone marrow, without changes in other immune or stromal cell compartments. Transient integrin alpha 6 beta 1-mediated interaction of NF B cells with laminin alpha 5 in the MZ supports the MZ B-cell population, their long-term survival, and antibody response. Data suggest that the unique 3D structure and biochemical composition of the ECM of lymphoid organs impacts on immune cell fate.
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| 45. |
- Toropov, A.A., et al.
(författare)
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Excitons as a probe of interface morphology in Cd(Zn)Se/ZnSe heterostructures
- 2000
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 166:1, s. 278-283
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Tidskriftsartikel (refereegranskat)abstract
- We present studies of the excitonic spectrum in superlattices (SLs) of CdSe insertions in a ZnSe matrix aimed at elucidating the CdSe/ZnSe interface morphology. The experimental photoluminescence excitation spectra are compared with the results of variational exciton calculations performed within the effective mass approximation. The shape of the average vertical (along the SL growth axis) distribution of CdSe within each insertion, used in the calculations, was obtained from a theoretical simulation of X-ray diffraction (XRD) rocking curves measured in the same samples. The results indicate that the thinnest layers are graded composition ZnCdSe quantum wells (QWs), generally homogeneous in the layer planes, whereas flat islands enriched by Cd appear at the CdSe nominal thickness larger than 0.5-0.6 monolayer (ML).
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| 46. |
- Toropov, A.A., et al.
(författare)
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III-V/II-VI heterovalent double quantum wells
- 2006
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 243:4, s. 819-826
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Tidskriftsartikel (refereegranskat)abstract
- We report on design, fabrication by molecular beam epitaxy, and photoluminescence (PL) studies of III-V/II-VI heterovalent structures containing a GaAs/AlGaAs/ZnSe/ZnCdMnSe double quantum well (QW). The studies of temperature-dependent and time-resolved PL have provided an insight into the nature of the exciton localization potential induced by the heterovalent interface. It is found that under the resonant conditions the observed emission mostly originates from the recombination of excitons confined in type II quantum-dot-like structures, where the holes are localised within the GaAs QW due to the well width fluctuations and the electrons are localized in the plane of the ZnCdMnSe QW due to the fluctuations of the conduction band offset at the heterovalent interface, induced by random variation of the interface microscopic structure. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA,.
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| 47. |
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| 48. |
- Alpy, F, et al.
(författare)
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Generation of a conditionally null allele of the laminin alpha 1 gene
- 2005
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Ingår i: Genesis: The Journal of Genetics and Development. - : Wiley. - 1526-954X. ; 43:2, s. 59-70
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Tidskriftsartikel (refereegranskat)abstract
- Laminins are heterotrimeric glycoproteins of the basement membranes. Laminin 1 (alpha 1, beta 1, gamma 1) is the major laminin expressed during early mouse embryogenesis. To gain access, to the physiological function of laminin alpha 1 chain, we developed a conditionally null allele of its encoding gene (Lama1) using the cre/loxP system. Floxed-allele-carrying mice (Lama1(flox/flox)) display no overt phenotype. Lama1(flox/flox) mice were crossed with transgenic deleter mice (CMV-Cre) to generate Lama1-deficient mice (Lama1(Delta/Delta)). Lama1(Delta/Delta) embryos die during the early postimplantation period after embryonic day 6.5. They lack Reichert's membrane, an extraembryonic basement membrane in which laminin all is normally highly expressed. In parallel, Lama1(Delta/Delta) embryos display 1) parietal and visceral endoderm differentiation defects with altered expression of cytokeratin 19 and GATA4, respectively, and 2) an induction of apoptosis. This new mouse model is of particular interest as it will allow time- and tissue-specific inactivation of the Lamal gene in various organs. genesis 43:59-70, 2005.
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| 49. |
- Alpy, F, et al.
(författare)
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The expression pattern of laminin isoforms in Hirschsprung disease reveals a distal peripheral nerve differentiation
- 2005
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Ingår i: Human Pathology. - : Elsevier BV. - 1532-8392 .- 0046-8177. ; 36:10, s. 1055-1065
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Tidskriftsartikel (refereegranskat)abstract
- Hirschsprung disease (HD), a developmental disorder, is associated with failure of enteric ganglia formation. Signaling molecules, including secreted basement membrane molecules, derived from the mesenchyme of the gut wall play an important role in the colonization and/or differentiation of the enteric nervous system. The current study aims to define the possible alterations of laminins involved in the pathogenesis of HD. Expression of the various laminin alpha, beta, and gamma chains, was assessed in the aganglionic, transitional, and ganglionic bowel segments of patients with HD or with other motor disorders. Cytoskeletal, neuronal, and glial markers were also included in this study. The major finding highlighted by the present work concerns the clear identification and location of myenteric aganglionic plexuses in HD with some of the laminin antibodies, which reveal a peripheral nerve type of differentiation. Furthermore, we could show an increase of laminin alpha 5 chain immunostaining in the dilated muscle of the ganglionic bowel upstream the distal aganglionic region in a subgroup of patients with HD, as well as a relocalization of laminin alpha 2 chain in the subepithelial basement membrane. Overall, these basement membrane molecules could provide useful markers for diagnosis of aganglionosis or hypoganglionosis.
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| 50. |
- Cagnazzo, Alessandra, et al.
(författare)
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Semiclassical equivalence of Green-Schwarz and pure-spinor/hybrid formulations of superstrings in AdS(5) x S-5 and AdS(2) x S-2 x T-6
- 2013
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Ingår i: Journal of Physics A. - : IOP Publishing. - 1751-8113 .- 1751-8121. ; 46:6, s. 065401-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the equivalence between the worldsheet one-loop partition functions computed near classical string solutions in the Green-Schwarz and in the pure-spinor formulations of superstrings in AdS(5) x S-5. While their bosonic sectors are the same in the conformal gauge, their fermionic sectors superficially appear to be very different (first versus second-derivative kinetic terms, presence versus absence of fermionic gauge symmetry). Still, we show that the quadratic fluctuation spectrum of 16 fermionic modes of the pure-spinor formulation is the same as in the Green-Schwarz superstring and the contribution of the extra 'massless' fermionic modes cancels against that of the pure-spinor ghosts. We also provide evidence for a similar semiclassical equivalence between the Green-Schwarz and the hybrid formulations of superstrings in AdS(2) x S-2 x T-6 by studying several particular examples of string solutions.
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