| 1. |
- de Peppo, G.M., et al.
(författare)
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Human Embryonic Mesodermal Progenitors Highly Resemble Human Mesenchymal Stem Cells and Display High Potential for Tissue Engineering Applications
- 2010
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 16:7, s. 2161-2182
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Tidskriftsartikel (refereegranskat)abstract
- Adult stem cells, such as human mesenchymal stem cells (hMSCs), show limited proliferative capacity and, after long-term culture, lose their differentiation capacity and are therefore not an optimal cell source for tissue engineering. Human embryonic stem cells (hESCs) constitute an important new resource in this field, but one major drawback is the risk of tumor formation in the recipients. One alternative is to use progenitor cells derived from hESCs which are more lineage restricted but do not form teratomas. We have recently derived a cell line from hESCs denoted human embryonic stem cell-derived mesodermal progenitors (hESMPs) and here, using genome wide microarray analysis, report that the process of hES-MPs derivation results in a significantly altered expression of hESCs characteristic genes to an expression level highly similar to that of hMSCs. However, hES-MPs displayed a significantly higher proliferative capacity and longer telomeres. Interestingly, the hES-MPs also demonstrated a lower expression of HLA class II proteins before and after interferon-γ treatment, indicating that these cells may somewhat be immunoprivileged and potentially used for HLA-incompatible transplantation. The hES-MPs are thus an appealing alternative to hMSCs in tissue engineering applications and stem cell-based therapies for mesodermal tissues.
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| 2. |
- Trujillo, F. J., et al.
(författare)
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Shrinkage Factor Analysis in the Dry Machining of UNS A92024 Alloy by FEM
- 2021
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Ingår i: 24th Innovative Manufacturing Engineering and Energy International Conference (IManEE 2020) 14<sup>th</sup>-15<sup>th</sup> December 2020, Athens, Greece. - : Institute of Physics (IOP).
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Konferensbidrag (refereegranskat)abstract
- Chip evacuation becomes a relevant factor in the dry machining of aeronautical aluminium alloys, either when they are machined as isotropic material or hybridized with other materials. Chip morphology and geometry highly depend on cutting parameters. Several works can be found in the literature focusing on the analysis of chip morphology of aluminium alloys at high cutting speeds but there is a lack of studies that apply low cutting speeds. FEM simulation may be useful to reduce the experimental time and cost of this kind of analysis. Therefore, in this work, the influence of feed-rate on several chip geometrical parameters (height of peaks, height of valleys and shrinkage factor) of dry turned UNS A92024 alloy has been analysed by FEM simulation. Three different energy fracture modes have been tested as damage evolution criterion, in order to get the mode that better fit the experimental chip morphology. In general, the mixed mode was the fracture energy mode that best suited the chip morphology behaviour, within wider feed-rate range.
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| 3. |
- Bermudo Gamboa, Carolina, et al.
(författare)
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Modeling of the fracture energy on the finite element simulation in Ti6Al4V alloy machining
- 2021
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- One of the main problems that exists when working with Finite Element Methods (FEM) applied to machining processes is the lack of adequate experimental data for simulating the material properties. Moreover, for damage models based on fracture energy, the correct selection of the energy value is critical for the chip formation process. It is usually difficult to obtain the fracture energy values and requires complex tests. In this work, an analysis of the influence of this fracture energy on the cutting force and the chip generation process has been carried out for different sets of cutting parameters. The aim is to present an empirical relationship, that allows selecting the fracture energy based on the cutting force and cutting parameters. The work is based on a FEM model of an orthogonal turning process for Ti6Al4V alloy using Abaqus/Explicit and the fracture energy empirical relation. This work shows that it is necessary to adjust the fracture energy for each combination of cutting conditions, to be able to fit the experimental results. The cutting force and the chip geometry are analyzed, showing how the developed model adapts to the experimental results. It shows that as the cutting speed and the feed increase, the fracture energy value that best adapts to the model decreases. The evolution shows a more pronounced decrease related to the feed increment and high cutting speed.
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| 4. |
- Svensson, A., et al.
(författare)
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European children's sugar intake on weekdays versus weekends: the IDEFICS study
- 2014
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Ingår i: European Journal of Clinical Nutrition. - : Springer Science and Business Media LLC. - 0954-3007 .- 1476-5640. ; 68:7, s. 822-828
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To compare the intake of total sugars, foods and drinks rich in added sugar, and energy in children on weekdays (Monday Thursday), Fridays and weekends. METHODS: Dietary intake (g, kJ, energy %) was assessed using a computerized 24-h recall method in a sample of 2- to 9-year-old children from Belgium, Cyprus, Estonia, Germany, Hungary, Italy, Spain and Sweden who were participating in the IDEFICS baseline study (2007-2008). Analyses were performed in 9497 children by selecting one 24-h recall per child (for comparison of weekdays vs weekends, and Fridays vs weekdays and weekends). Selected stratified analyses were performed by country and age group. RESULTS: Intake of total sugars exceeded 20 energy % in all countries but one. In the non-stratified analyses, the intakes of total sugars and foods and drinks rich in added sugar were found to be higher on weekends compared with weekdays (both P < 0.001), and intakes on Fridays were a mix between intakes on weekdays and weekends. Energy intake did not differ between weekdays and weekends. Results were somewhat heterogeneous, both across countries and age groups. CONCLUSIONS: High intake of sugar remains an important nutritional problem in children of many European countries. Interventions aiming to prevent this diet pattern may optimize their impact by targeting dietary habits on Fridays and weekends. Furthermore, when conducting dietary assessment in children, data from weekends and Fridays in combination with a selection of Mondays to Thursdays are needed to capture habitual sugar intake. Age and dietary cultures should also be considered in dietary intervention and assessment as effect modifications were seen for both age and country.
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