A theoretical structure−property relation between pK a and Bader's atoms in molecules (AIM) energy of the dissociating proton was obtained by an approximation of the standard gas-phase expression for the equilibrium constant expressed in terms of molecular partition functions. This relation was then tested by solvated density functional computations on a series of aliphatic carboxylic acids, substituted benzoic acids, phenols, anilinium ions, and pyridinium ions using the COSMO solvation model. Comparison with accurate experimental values indicates that average unsigned errors of generally less than 0.2 pK a units can be achieved in the calculation of relative pK a values. The inclusion of specifically hydrogen-bonded water molecules in the vicinity of the dissociating proton was found to improve the agreement between theory and experiment greatly. Computed pK a values for some diprotic acids were also investigated.

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: High-quality magnesium hydroxide powders can be produced by hydrating slow-reacting magnesia in dilute magnesium acetate solutions. The kinetics of this process are very crucial for process design and control, and for the production of a powder with desirable particle morphology. In this work, industrial heavily-burned magnesia powders were hydrated in 0.01-0.1 mol dm-3 magnesium acetate solutions at temperatures ranging between 333 and 363 K. Examination of the magnesium hydroxide produced and the analysis of the kinetic data suggest that the hydration of heavily burned magnesia in magnesium acetate solutions is a dissolution-precipitation process controlled by the dissolution of magnesia particles. The activation energy was estimated to be 60 kJ mol-1, while the reaction order with respect to acetate concentration was found to be about one.1999 Society of Chemical Industry (

There is evidence to suggest the efficacy of Crocus (saffron) in the management of cognitive decline. This study examined the efficacy of Crocus in patients with amnesic and multi domain MCI (aMCImd). The participants included 17 patients on Crocus and 18 on a waiting list, who were examined with a short neuropsychological battery, MRI 3T, while some patients were examined via 256-channel electroencephalogram (HD-EEG) at baseline and after 12 months. The results showed that patients on Crocus had improved Mini-Mental State Examination scores (p = 0.015), while the control group deteriorated. Also, MRI, EEG, and ERP showed improvement in specific domains. This led us to conclude that Crocus is a good choice for management of aMCImd.