Synthesis of core-shell copper-graphite submicronic particles and carbon nano-onions by spark discharges in liquid hydrocarbons.

Spark discharge in hydrocarbon liquids is considered a promising method for the synthesis of various nanomaterials, including nanocomposites. In this study, copper-carbon particles were synthesized by generating spark discharges between two Cu electrodes immersed in heptane, cyclohexane, or toluene. The synthesized particles were characterized using scanning electron microscopy, high-resolution transmission electron microscopy, and selected area electron diffraction. Overall, two families of particles were observed: Cu particles (diameter < 10 nm) embedded in a carbon matrix and submicrometric Cu particles encapsulated in a carbon shell. The obtained results indicate that the size distribution of the Cu nanoparticles and the degree of graphitization of the carbon matrix depend on the liquid. Indeed, discharges in heptane lead to Cu particles with diameters of 2-6 nm embedded in a carbon matrix of low graphitization degree, while discharges in toluene result in particles with diameters of 2-14 nm embedded in carbon matrix of high graphitization degree. Based on the obtained experimental results, it is proposed that the Cu nanoparticles are produced in the plasma core where Cu (evaporated from the electrode surface) and carbonaceous species (decomposition of the liquid) are present. When the plasma hits the electrode surface, hot (thousands of Kelvin) Cu particles are ejected from the electrode, and they propagate in the liquid. The propagation of the hot particles in the liquid results in the local evaporation of this liquid, which leads to the formation of a C-shell around each Cu particle. In few cases where the shape of the Cu particle is not spherical, carbon nanoonions are detected between the C-shell and the Cu core. These nanoonions are supposedly formed under the effect of the fluid vortices generated close to the particle surfaces when these latter are ejected into the liquid.

Knowledge of and attitudes expressed toward epilepsy by carers of people with epilepsy: a UK perspective.

OBJECTIVE: The aim of this study was to investigate the knowledge and attitudes possessed by carers of people with epilepsy. METHODS: A postal survey of 2000 carers recruited from the membership list of a UK epilepsy charity was conducted using a standard set of questions. The questions covered their knowledge of epilepsy (e.g., estimating prevalence and identifying causes of epilepsy) and their attitudes (e.g., about the characteristics of people with epilepsy). RESULTS: Overall, 651 carers responded. Only 29% of carers were male, with the majority between 40 and 60 years of age. The majority of respondents (76%) overestimated the prevalence of epilepsy. Twenty-five percent believed that epilepsy was caused by stress. The majority of respondents believed that people with epilepsy were treated differently by others. Only a small percentage believed that people with epilepsy should be barred from such professions as teaching and nursing. CONCLUSIONS: Carers of people with epilepsy generally possessed high levels of knowledge about most aspects of epilepsy, and their attitudes toward those with epilepsy were benign. There were, however, particular groups who were more likely to hold more positive attitudes, and these included younger and better-educated individuals. Limitations of this study include that the sample was self-selected and that only a third of the people to whom the questionnaire was mailed responded.

Neuropsychological effects of exposure to anticonvulsant medication in utero.

OBJECTIVE: To investigate the long-term differential drug effects on cognitive functioning in school-aged children exposed to antiepileptic drugs (AEDs) in utero. METHODS: Mothers with epilepsy were recruited from specialist epilepsy clinics and obstetric clinics from the Liverpool and Manchester region. The mothers and their children were recruited without prior knowledge of their AED treatment during pregnancy or the health of the offspring. A battery of neuropsychological tests was applied to each mother-child pair in order to obtain a neuropsychological profile for each child. RESULTS: Neuropsychological investigation was performed on 249 children between the ages of 6 and 16. Children exposed to sodium valproate had a significantly lower verbal IQ when compared to children exposed to other antiepileptic drugs or not exposed at all. The same children were more likely to have an IQ below 69 and more likely to have memory impairment when compared to the other groups. The mothers' IQ, exposure to sodium valproate, and the number of tonic-clonic seizures during pregnancy were significant predictors of verbal IQ in this population. CONCLUSIONS: This retrospective study highlights the potential harmful effects of sodium valproate exposure in utero on neuropsychological development.

The longer term outcome of children born to mothers with epilepsy.

OBJECTIVES: To determine the prevalence of cognitive delay and possible associated dysmorphic features in children exposed to antiepileptic drugs (AEDs) in utero. DESIGN: Retrospective study of children born to mothers with epilepsy. SETTING: Regional epilepsy clinics in Liverpool and Manchester, UK. PARTICIPANTS: Children aged between 6 months and 16 years born to mothers with epilepsy. MAIN OUTCOME MEASURES: Structured interviews, hospital records, clinical examination, and psychometric tests (Wechsler) were used to assess exposure and intelligence quotient (IQ). Blinded assessment of photographs was used to score children with characteristic dysmorphic features. RESULTS: A total of 249 children aged 6 and over were studied: 41 were exposed to sodium valproate, 52 to carbamazepine, 21 to phenytoin, 49 to polytherapy, and 80 were unexposed. Mean verbal IQ was significantly lower in the valproate group compared to unexposed and other monotherapy groups. Multiple regression analysis showed that both valproate exposure and frequent tonic-clonic seizures in pregnancy were significantly associated with a lower verbal IQ despite adjusting for other confounding factors. There was a significant negative correlation between dysmorphic features and verbal IQ in children exposed to valproate. CONCLUSIONS: This study identifies valproate as a drug carrying potential risks for developmental delay and cognitive impairment and is the first to suggest that frequent tonic-clonic seizures have a similar effect. Our results need to be interpreted with caution given their retrospective nature. Women with epilepsy need careful counselling about individual risk benefit of AED treatment before pregnancy.