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- Accomando, E., et al.
(författare)
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Physics with e + e - linear colliders
- 1998
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Ingår i: Physics Reports. - 0370-1573. ; 299:1, s. 1-78
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Tidskriftsartikel (refereegranskat)abstract
- The physics potential of e + e - linear colliders is summarized in this report. These machines are planned to operate in the first phase at a center-of-mass energy of 500 GeV, before being scaled up to about 1 TeV. In the second phase of the operation, a final energy of about 2 TeV is expected. The machines will allow us to perform precision tests of the heavy particles in the Standard Model, the top quark and the electroweak bosons. They are ideal facilities for exploring the properties of Higgs particles, in particular in the intermediate mass range. New vector bosons and novel matter particles in extended gauge theories can be searched for and studied thoroughly. The machines provide unique opportunities for the discovery of particles in supersymmetric extensions of the Standard Model, the spectrum of Higgs particles, the supersymmetric partners of the electroweak gauge and Higgs bosons, and of the matter particles. High precision analyses of their properties and interactions will allow for extrapolations to energy scales close to the Planck scale where gravity becomes significant. In alternative scenarios, i.e. compositeness models, novel matter particles and interactions can be discovered and investigated in the energy range above the existing colliders up to the TeV scale. Whatever scenario is realized in Nature, the discovery potential of e + e - linear colliders and the high precision with which the properties of particles and their interactions can be analyzed, define an exciting physics program complementary to hadron machines.
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| 8. |
- Marklund, S, et al.
(författare)
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Molecular basis for the dominant white phenotype in the domestic pig.
- 1998
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Ingår i: Genome research. - 1088-9051. ; 8:8, s. 826-33
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Tidskriftsartikel (refereegranskat)abstract
- The change of phenotypic traits in domestic animals and crops as a response to selective breeding mimics the much slower evolutionary change in natural populations. Here, we describe that the dominant white phenotype in domestic pigs is caused by two mutations in the KIT gene encoding the mast/stem cell growth factor receptor (MGF), one gene duplication associated with a partially dominant phenotype and a splice mutation in one of the copies leading to the fully dominant allele. The splice mutation is a G to A substitution in the first nucleotide of intron 17 and leads to skipping of exon 17. The duplication is most likely a regulatory mutation affecting KIT expression, whereas the splice mutation is expected to cause a receptor with impaired or absent tyrosine kinase activity. Immunocytochemistry showed that this variant form is expressed in 17- to 19-day-old pig embryos. Hundreds of millions of white pigs around the world are assumed to be heterozygous or homozygous for the two mutations. [The EMBL accession numbers for porcine KIT1*0101, KIT1*0202, KIT2*0202, and KIT2*0101 are AJ223228-AJ223231, respectively.]
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| 10. |
- Rubio, F. T., et al.
(författare)
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BDNF gene transfer to the mammalian brain using CNS-derived neural precursors
- 1999
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Ingår i: Gene Therapy. - : Springer Science and Business Media LLC. - 0969-7128 .- 1476-5462. ; 6:11, s. 1851-1866
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Tidskriftsartikel (refereegranskat)abstract
- Neural stem cell lines represent a homogeneous source of cells for genetic, developmental, and gene transfer and repair studies in the nervous system. Since both gene transfer of neurotrophic factors and cell replacement strategies are of immediate interest for therapeutical purposes, we have generated BDNF-secreting neural stem cell lines and investigated to what extent different endogenous levels of BDNF expression affect in vitro survival, proliferation and differentiation of these cells. Also we have investigated the in vivo effects of such BDNF gene transfer procedure in the rat neostriatum. Hippocampus- and cerebellum-derived cell lines reacted differently to manipulations aimed at varying their levels of BDNF production. Overexpression of BDNF enhanced survival of both cell types, in a serum-deprivation assay. Conversely, and ruling out unspecific effects, expression of an antisense version of BDNF resulted in compromised survival of cerebellum-derived cells, and in a lethal phenotype in hippocampal progenitors. These data indicate that endogenous BDNF level strongly influences the in vitro survival of these cells. These effects are more pronounced for hippocampus- than for cerebellum-derived progenitors. Hippocampus-derived BDNF overproducers showed no major change in their capacity to differentiate towards a neuronal phenotype in vitro. In contrast cerebellar progenitors overproducing BDNF did not differentiate into neurons, whereas cells expressing the antisense BDNF construct generated cells with morphological features of neurons and expressing immunological neuronal markers. Taken together these results provide evidence that BDNF controls both the in vitro survival and differentiation of neural stem cells. After in vivo transplantation of BDNF-overproducing cells to the rat neostriatum, these survived better than the control ones, and induced the expected neurotrophic effects on cholinergic neurons. However, long-term (3 months) administration of BDNF resulted in detrimental effects, at this location. These findings may be of importance for the understanding of brain development, for the design of therapeutic neuro-regenerative strategies, and for cell replacement and gene therapy studies.
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