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- Brett, Calvin J., et al.
(författare)
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Revealing structural evolution occurring from photo-initiated polymer network formation
- 2020
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Ingår i: Communications Chemistry. - : Springer Science and Business Media LLC. - 2399-3669. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Photopolymerization is a key enabling technology offering spatial and temporal control to allow for future functional materials to be made to meet societal needs. However, gaining access to robust experimental techniques to describe the evolution of nanoscale morphology in photo-initiated polymeric systems has proven so far to be a challenging task. Here, we show that these physical transformations can be monitored and quantified at the nanoscale in situ and in real-time. It is demonstrated that the initial structural features of the liquid precursors significantly affect the final morphology and the physical properties of the resulting solid via the occurrence of local heterogeneities in the molecular mobility during the curing transformation. We have made visible how local physical arrestings in the liquid, associated with both cross-linking and vitrification, determine the length scale of the local heterogeneities forming upon curing, found to be in the 10-200nm range. Acomplete account of the structural evolution occurring during photopolymerisation is lacking. Here the physical changes occurring on the nanometer scale during photopolymerisation of acrylates are followed over time by FTIR, X-ray reflectometry, AFM, and GISAXS, offering insight into the mechanism by which initial composition influences the final morphology.
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| 3. |
- van Santen, S. S., et al.
(författare)
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Fractures, Bone Mineral Density, and Final Height in Craniopharyngioma Patients with a Follow-up of 16 Years
- 2020
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Ingår i: Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 105:4
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Tidskriftsartikel (refereegranskat)abstract
- Context: Pituitary hormonal deficiencies in patients with craniopharyngioma may impair their bone health. Objective: To investigate bone health in patients with craniopharyngioma. Design: Retrospective cross-sectional study. Setting: Dutch and Swedish referral centers. Patients: Patients with craniopharyngioma (n = 177) with available data on bone health after a median follow-up of 16 years (range, 1-62) were included (106 [60%] Dutch, 93 [53%] male, 84 [48%] childhood-onset disease). Main outcome measures: Fractures, dual X-ray absorptiometry-derived bone mineral density (BMD), and final height were evaluated. Low BMD was defined as T- or Z-score <=-1 and very low BMD as <=-2.5 or <=-2.0, respectively. Results: Fractures occurred in 31 patients (18%) and were more frequent in men than in women (26% vs. 8%, P = .002). Mean BMD was normal (Z-score total body 0.1 [range, -4.1 to 3.5]) but T- or Z-score <=-1 occurred in 47 (50%) patients and T-score <=-2.5 or Z-score <=-2.0 in 22 (24%) patients. Men received less often treatment for low BMD than women (7% vs. 18%, P = .02). Female sex (OR 0.3, P = .004) and surgery (odds ratio [OR], 0.2; P = .01) were both independent protective factors for fractures, whereas antiepileptic medication was a risk factor (OR, 3.6; P = .03), whereas T-score <=-2.5 or Z-score <=-2.0 was not (OR, 2.1; P = .21). Mean final height was normal and did not differ between men and women, or adulthood and childhood-onset patients. Conclusions: Men with craniopharyngioma are at higher risk than women for fractures. In patients with craniopharyngioma, a very low BMD (T-score <=-2.5 or Z-score <=-2.0) seems not to be a good predictor for fracture risk.
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