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- Adebahr, Josefina, 1973, et al.
(author)
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Ion transport in polymer electrolytes containing nanoparticulate TiO2: The influence of polymer morphology
- 2003
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In: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 5:4, s. 720-725
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Journal article (peer-reviewed)abstract
- Recent studies have shown that composite polymer electrolytes, formed by dispersing nanosized ceramic particles in polyether-based electrolytes, have improved ion transport properties as compared to their unfilled analogues. In the present study polymer electrolytes with different loadings of nano-sized ceramic particles (TiO 2 ) and different polymer chemistry and morphology have been investigated. Of special interest are filler induced effects on polymer, solvent and cationic mobility. Partly crystalline polymer electrolytes based on poly(ethylene oxide) have been compared to fully amorphous polymer electrolytes based on a polyether urethane, as well as gel electrolytes based on PMMA. 7 Li pfg-NMR, linewidth and spin-spin relaxation times as well as 1 H pfg-NMR and spin-spin relaxation times, were measured as a function of temperature and composition. The 1 H spin-spin relaxation measurements reveal increased average polymer mobility with the addition of filler up to a maximum at 4 and 8 wt.% TiO 2 for the fully amorphous and the partly crystalline electrolytes, respectively. The 7 Li linewidth measurements for the fully amorphous system show a broadening of the linewidth with addition of filler. Based on variable temperature measurements this broadening is interpreted as a result of the inhomogeneity introduced by the filler particles. Pulsed field gradient (pfg) diffusion measurements were employed to determine ion and solvent self-diffusion coefficients. In the case of the PMMA-based gel electrolyte and the fully amorphous electrolytes enhanced cation self-diffusion was observed upon addition of TiO 2 .
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| 3. |
- Kelly, BD, et al.
(author)
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Obstetric adversity and age at first presentation with schizophrenia: Evidence of a dose-response relationship
- 2004
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In: American Journal of Psychiatry. - 1535-7228. ; 161:5, s. 920-922
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Journal article (peer-reviewed)abstract
- Objective: The purpose of the study was to determine if a dose-response relationship exists between obstetric adversity and age at first presentation with schizophrenia. Method: The Dublin Psychiatric Case Register was used to identify subjects with schizophrenia. Data on obstetric complications, social class of origin, and family history of psychiatric illness were obtained for those subjects. Results: A total of 409 patients with ICD-9 schizophrenia were identified. Patients with a history of obstetric complications presented earlier to psychiatric services. As the number of complications increased, the mean age at first presentation decreased. This effect was independent of social class of origin and family history of psychiatric illness. Conclusions: Obstetric adversity exerts an independent influence on the age at first presentation with schizophrenia, in a dose-response manner. This finding supports the existence of a causal relationship between obstetric adversity and age at first presentation with schizophrenia.
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