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| 2. |
- Wronkowska, A.A., et al.
(author)
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Lattice absorption of Be-containing semiconductor alloys determined by spectroscopic ellipsometry
- 2008
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In: Physica Status Solidi (a) applications and materials science. - Weinheim, Germany : Wiley-VCH Verlagsgesellschaft. - 1862-6300 .- 1862-6319. ; 205:4, s. 849-853
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Journal article (peer-reviewed)abstract
- Lattice absorption of Zn1–x –yBex Mgy Se and Cd1–x –yBex Zny Se mixed crystals grown by a high pressure Bridgman method has been investigated by infrared spectroscopic ellipsometry in the wave number range from 230 cm–1 to 5000 cm–1. Ellipsometric spectra of Cd1–x –yBex Zny Se crystals display features in the spectral range 350–550 cm–1 associated with BeSe-type phonon modes. In the optical spectra of Zn1–x –yBex Mgy Se crystals both BeSe-type and MgSe-type lattice absorption bands are detected. The MgSe-like modes are located at approximately 300 cm–1. The frequencies and oscillator strengths of optical phonon modes depend strongly on the alloy composition
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| 3. |
- de Pablo, Yolanda, et al.
(author)
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Vimentin Phosphorylation Is Required for Normal Cell Division of Immature Astrocytes
- 2019
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In: Cells. - : MDPI AG. - 2073-4409. ; 8:9
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Journal article (peer-reviewed)abstract
- Vimentin (VIM) is an intermediate filament (nanofilament) protein expressed in multiple cell types, including astrocytes. Mice with VIM mutations of serine sites phosphorylated during mitosis (VIMSA/SA) show cytokinetic failure in fibroblasts and lens epithelial cells, chromosomal instability, facilitated cell senescence, and increased neuronal differentiation of neural progenitor cells. Here we report that in vitro immature VIMSA/SA astrocytes exhibit cytokinetic failure and contain vimentin accumulations that co-localize with mitochondria. This phenotype is transient and disappears with VIMSA/SA astrocyte maturation and expression of glial fibrillary acidic protein (GFAP); it is also alleviated by the inhibition of cell proliferation. To test the hypothesis that GFAP compensates for the effect of VIMSA/SA in astrocytes, we crossed the VIMSA/SA and GFAP(-/-) mice. Surprisingly, the fraction of VIMSA/SA immature astrocytes with abundant vimentin accumulations was reduced when on GFAP(-/-) background. This indicates that the disappearance of vimentin accumulations and cytokinetic failure in mature astrocyte cultures are independent of GFAP expression. Both VIMSA/SA and VIM(SA/SA)GFAP(-/-) astrocytes showed normal mitochondrial membrane potential and vulnerability to H2O2, oxygen/glucose deprivation, and chemical ischemia. Thus, mutation of mitotic phosphorylation sites in vimentin triggers formation of vimentin accumulations and cytokinetic failure in immature astrocytes without altering their vulnerability to oxidative stress.
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| 4. |
- Wilhelmsson, Ulrika, 1970, et al.
(author)
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Nestin Regulates Neurogenesis in Mice Through Notch Signaling From Astrocytes to Neural Stem Cells
- 2019
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In: Cerebral Cortex. - : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 29:10, s. 4050-4066
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Journal article (peer-reviewed)abstract
- The intermediate filament (nanofilament) protein nestin is a marker of neural stem cells, but its role in neurogenesis, including adult neurogenesis, remains unclear. Here, we investigated the role of nestin in neurogenesis in adult nestin-deficient (Nes(-/-)) mice. We found that the proliferation of Nes(-/-) neural stem cells was not altered, but neurogenesis in the hippocampal dentate gyrus of Nes(-/-) mice was increased. Surprisingly, the proneurogenic effect of nestin deficiency was mediated by its function in the astrocyte niche. Through its role in Notch signaling from astrocytes to neural stem cells, nestin negatively regulates neuronal differentiation and survival; however, its expression in neural stem cells is not required for normal neurogenesis. In behavioral studies, nestin deficiency in mice did not affect associative learning but was associated with impaired long-term memory.
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