27 research outputs found

    Magnetization measurements on ITER Nb3Sn CICC and strands subjected to irreversible degradation

    Get PDF
    We investigated the impact of irreversible strain changes and filament cracking on the AC losses of several Nb3Sn strands and a full-size ITER cable-in-conduit-conductor (CICC). The aim is to evaluate whether the presence of filament cracks in full-size ITER Nb3Sn CICC (after cyclic loading) can be detected without extracting strands from the cable for microscopic observation. The strand AC loss was measured in a magnetometer in virgin condition and after an applied periodic and cyclic bending strain. The filament fracture pattern was determined afterwards by SEM analysis. \ud \ud We found a significant decrease of the hysteresis loss in ITER bronze and internal-tin type strands with increasing filament fracture density. However, in the experimental comparison between a highly degraded section of a full-size ITER TF CICC sample subjected to high electromagnetic load and a section taken from the low magnetic field zone, no clear difference is observed in hysteresis loss but only in coupling loss. \ud \ud The first measurement on a full-size ITER CICC sample indicates that the amount of cracks is at least restricted to an average crack density of 0.05 cracks/filament/mm but a higher accuracy of the CICC AC loss measurement is required for better precision. Further work is required to evaluate whether the observed degradation of the current sharing temperature and n-value is essentially attributed to strand deformation and associated periodic strain variations or filament cracks. \u

    Parthenogenic blastocysts cultured under in vivo conditions exhibit proliferation and differentiation expression genes similar to those of normal embryos

    Full text link
    Parthenote embryos offer multiple possibilities in biotechnological investigation, such as stem cell research. However, there is still a dearth of knowledge of this kind of embryo. In this study, development and ploidy were analysed in parthenotes under in vitro and in vivo culture conditions. Subsequently, using real-time PCR, the expressions of factor OCT-4, Vascular Endothelial Growth Factor, Epidermal Growth Factor Receptor 3 and Transforming Growth Factor ß2 genes were analysed to compare the embryo types at the blastocyst stage. Development and implantation of parthenote embryos were described after transfer at day 10 of pregnancy. Parthenotes showed similar blastocyst development for both culture conditions and most of the parthenotes produced were diploid. However, parthenotes developed under in vivo conditions showed similar mRNA expression of OCT-4, VEGF and TGF-ß2 to 5 and 6 day old blastocysts. In contrast, parthenotes developed under in vitro conditions had altered the expression pattern of these genes, except for erbB3 mRNA. Finally, transferred parthenotes had the ability to implant but showed severe growth retardation and lesser size. This is the first demonstration of the influence of culture conditions on parthenote mRNA expression. Our study highlights the importance of culture conditions in subsequent uses of parthenotes, such as the production of stem cell lines. © 2011 Elsevier B.V.This work was supported by Generalitat Valenciana research program (Prometeo 2009-8260: 125) and by the Spanish Research Projects (CICYT AGL2008-03274). The authors thank Neil Macowan Language Services for revising the English version of the manuscript.Naturil Alfonso, C.; Saenz De Juano Ribes, MDLD.; Peñaranda, D.; Vicente Antón, JS.; Marco Jiménez, F. (2011). Parthenogenic blastocysts cultured under in vivo conditions exhibit proliferation and differentiation expression genes similar to those of normal embryos. Animal Reproduction Science. (127):222-228. https://doi.org/10.1016/j.anireprosci.2011.08.005S22222812
    corecore