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- Löfqvist, Chatarina, 1964, et al.
(author)
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Low Postnatal Serum IGF-I levels is Associated with Bronchopulmonary Dysplasia (BPD).
- 2012
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In: Acta paediatrica. - : Wiley. - 1651-2227 .- 0803-5253. ; 101:12, s. 1211-1216
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Journal article (peer-reviewed)abstract
- Aim: To characterize postnatal changes in serum IGF-I in relation to development of bronchopulmonary dysplasia (BPD) in very preterm infants. Methods: Longitudinal study of 108 infants with mean (SD) gestational age 27.2 (2.2) weeks. Weekly serum samples of IGF-I were analyzed from birth until postmenstrual age 36 weeks. Multivariate models were developed to identify independent predictors of BPD. Results: Postnatal mean IGF-I levels at postnatal day 3 to 21 were lower in infants with BPD compared to infants with no BPD (16 vs. 26 ug/L, p<0.001). Longitudinal postnatal change in IGF-I levels (IGF-I regression coefficient (β), postnatal days 3 to 21, was lower in infants with BPD compared to infants with no BPD (0.28 vs. 0.97, p=0.002) and mean IGF-I during postmenstrual age 30-33 weeks was lower in infants with BPD as compared to infants without BPD (22 vs. 29 ug/L, p<0.001). In a binomial multiple regression model lower gestational age, male gender and lower mean serum IGF-I levels during postnatal day 3-21 were the most predictive risk factors associated with BPD (r(2) =0.634, p<0.001). Conclusion: Lower IGF-I concentrations during the first weeks after very preterm birth are associated with later development of BPD. © 2012 The Author(s)/Acta Paediatrica © 2012 Foundation Acta Paediatrica.
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- Odenberger, Eva-Lis, et al.
(author)
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Direct-hit development of manufacturing processes: Thermo-mechanical forming of Titanium aero engine structures
- 2013
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In: Book of Abstracts for the 4:th CEAS Conference, 2013. - Linköping : Linkoping University Electronic Press. - 9789175195209 ; , s. 175-
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Conference paper (peer-reviewed)abstract
- In order to increase the competitiveness of the Swedish aerospace industry, alternative manufacturing processes for static load carrying aero engine structures are desired. Presently, these components mainly consist of large-scaled single castings. To increase the in-house level of processing, the Swedish aero engine industry focus on fabricated alternatives by introducing new manufacturing processes and create relations with adjacent sub-suppliers. Theconcept of fabrication involves forgings, sheet metals and small ingots assembled by welding. The possibility to reduce weight, i.e. fuel consumption and product cost also exists. In the aerospace industry extremely highdemands on safety and reliability exists which requires precise knowledge regarding the influence on the material and its properties through the whole fabrication chain. The advanced Finite Element (FE) technology makes precise analyses possible assuming that proper material descriptions are used. Analyses of sheet metal forming provides with information of formability, thinning, springback, resultant mechanical properties and residual stress state which are important input to analyses of subsequent welding and heat treatments. One challenge in producing complete structures based on fabrication isrelated to the accuracy in numerical predictions of shape deviation using FE-analyses, in order to effectively compensate forming tools forspringback and accumulated shape distortions. By fundamental research on and development of thermo-mechanical processes for hot sheet metal forming of titanium, this project shall result in that a few SME can further developtheir processes for product and process development. The project gather competence from the Swedish aero engine industry GKN Aerospace, acknowledged R&D within forming processes, FE-modelling and SME withexperience of forming. The aims of the project are:Development of methodologies for thermomechanical material characterisation of Ti-6Al- 4V and FE-models for hot sheet metal forming. Suggestion of forming procedures suitable for production of titanium components in which resultant geometry and properties are secured.Activities where Swedish SME takes necessary development steps, in order to produce desired titanium sheet metal parts and develop into new sub-suppliers for the Aero engine industry. This presentation summarise results obtained inpresent and previous research and development projects regarding short lead time design, compensation and manufacturing of deep drawing tools of titanium and super alloys. The research funding by VINNOVA - NFFP 4 and 5for SME, BFS and GKN Aerospace Sweden are gratefully acknowledged.
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