Mechanism of the hydropyrolysis of Manvers coal

Manvers coal has been pyrolysed to 500ºC in a stirred autoclave under various pressures of nitrogen (pyrolysis) and hydrogen (hydropyrolysis). All products were investigated. Pyrolysis of coals involves the transfer of hydrogen atoms from one part of their structure to another. In the above experiments there was no way of labelling the hydrogen or of distinguishing between hydrogen which was initially part of the coal and hydrogen originating in the external atmosphere. Consequently, Manvers coal has been pyrolysed in an atmosphere of deuterium in order to obtain greater insight into the mechanism of hydropyrolysis. In particular it was hoped to distinguish between direct hydrogenation (deuteration!) of the coal and the products of pyrolysis and the 'shuttling' of hydrogen atoms between different parts of the pyrolysing coal. The addition to the coal of 5% (wt.% of coal) of either tetralin or pyrite was also studied. A variety of techniques were used to analyse the products of pyrolysis: gas chromatography - mass spectrometry and high performance liquid chromatography for tars; thermal conductivity gas chromatography and high resolution mass spectrometry for gases; methanol densities, microporosities and diffuse reflectance infra red spectroscopy for the cokes (chars); refractive index to determine deuterium in the liquor. An attempt has been made to apply basic thermodynamics to reactions which are likely to occur in the hydropyrolysis of coals. Diffusion and effusion rates for hydrogen and tar molecules have also been estimated.

Glue ear, hearing loss and IQ:an association moderated by the child's home environment

BACKGROUND: Glue ear or otitis media with effusion (OME) is common in children and may be associated with hearing loss (HL). For most children it has no long lasting effects on cognitive development but it is unclear whether there are subgroups at higher risk of sequelae. OBJECTIVES: To examine the association between a score comprising the number of times a child had OME and HL (OME/HL score) in the first four/five years of life and IQ at age 4 and 8. To examine whether any association between OME/HL and IQ is moderated by socioeconomic, child or family factors. METHODS: Prospective, longitudinal cohort study: the Avon Longitudinal Study of Parents and Children (ALSPAC). 1155 children tested using tympanometry on up to nine occasions and hearing for speech (word recognition) on up to three occasions between age 8 months and 5 years. An OME/HL score was created and associations with IQ at ages 4 and 8 were examined. Potential moderators included a measure of the child's cognitive stimulation at home (HOME score). RESULTS: For the whole sample at age 4 the group with the highest 10% OME/HL scores had performance IQ 5 points lower [95% CI -9, -1] and verbal IQ 6 points lower [95% CI -10, -3] than the unaffected group. By age 8 the evidence for group differences was weak. There were significant interactions between OME/HL and the HOME score: those with high OME/HL scores and low 18 month HOME scores had lower IQ at age 4 and 8 than those with high OME/HL scores and high HOME scores. Adjusted mean differences ranged from 5 to 8 IQ points at age 4 and 8. CONCLUSIONS: The cognitive development of children from homes with lower levels of cognitive stimulation is susceptible to the effects of glue ear and hearing loss.