The empirical success of the Peng-Robinson equation of state (PREOS) is unmatched; there is no other simple equation of state of the van der Waals form that has shown such wide and reliable applicability to the calculation of vapor-liquid equilibria (VLE) for systems containing light hydrocarbons, permanent gases, carbon dioxide and hydrogen sulfide. PREOS is one of the great success stories of applied chemical engineering thermodynamics. However, PREOS also has limitations; two of these are addressed here. Theoretically-based extensions are presented first, for including water and aqueous hydrocarbon mixtures and second, for induding'salt in water and in aqueous hydrocarbon mixtures. Illustrative examples show that these extensions are successful for VLE (where L refers to' a hydrocarbon liquid dilute in water) and for VLE (where L refers to saline water). Because the extension to include water, based on SAFT (Statistical Association Fluid Theory), cannot properly take into account the welldocumented hydrophobic effect, it is not yet possible to give a good representation of phase equilibria when one of the phases is a dilute aqueous liquid solution of hydrocarbon where the hydrophobic effect is significant.

The authors carried out a door-to-door survey to determine the prevalence of epilepsy among 55,000 people in China. The lifetime prevalence was 7.0/1000, and 41% of all persons had never received appropriate treatment. The prevalence of active epilepsy was 4.6/1000, and 63% of people with active epilepsy had not received antiepileptic treatment in the week before the survey. Figures for the prevalence and the treatment gap were significantly higher than previous estimates.

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and yyySEIN -Epilepsy Institute in the Netherlands Foundation, Heemstede, The Netherlands SUMMARY Purpose: Detailed data on the mortality of epilepsy are still lacking from resource-poor settings. We conducted a long-term follow-up survey in a cohort of people with convulsive epilepsy in rural areas of China. In this longitudinal prospective study we investigated the causes of death and premature mortality risk among people with epilepsy. Methods: We attempted to trace all 2,455 people who had previously participated in a pragmatic assessment of epilepsy management at the primary health level. Putative causes of death were recorded for those who died, according to the International Classification of Diseases. We estimated proportional mortality ratios (PMRs) for each cause, and standardized mortality ratios (SMRs) for each age-group and cause. Survival analysis was used to detect risk factors associated with increased mortality.Key Findings: During 6.1 years of follow-up there were 206 reported deaths among the 1,986 people with epilepsy who were located. The highest PMRs were for cerebrovascular disease (15%), drowning (14%), self-inflicted injury (13%), and status epilepticus (6%), with probable sudden unexpected death in epilepsy (SUDEP) in 1%. The risk of premature death was 2.9 times greater in people with epilepsy than in the general population. A much higher risk (SMRs 28-37) was found in young people. Duration of epilepsy and living in a waterside area were independent predictors for drowning. Significance: Drowning and status epilepticus were important, possibly preventable, causes of death. Predictors of increasing mortality suggest interventions with efficient treatment and education to prevent premature mortality among people with epilepsy in resource-poor settings.