Periodic Hartree-fock Study of A Weakly Bonded Layer Structure - Brucite Mg(oh)2

The layered mineral brucite Mg(OH), is investigated theoretically using an ab initio all-electron linear combination of atomic orbitals Hartree-Fock (HF) approximation. At the HF level, the interlayer interaction is weak and the interlayer distance is larger than the experimental one. Bonding is discussed on the basis of density of states and charge-density maps. No hydrogen bond is characterized. A posteriori correction of the energy for the correlation error is performed by use of the functional approach. The three semilocal functional formulas used yield similar results. This brings in extra interlayer bonding interaction, and yields a calculated geometry in agreement with experiments. The analysis of the interlayer bondings shows that it is mainly of dispersion type, and that the used functionals account for dispersion, in particular at short interatomic distances

Total cholesterol level and recovery from disability among hospitalized older adults

BACKGROUND: The association between total serum cholesterol and health outcomes among older adults is controversial. The objective of the present study was to determine within a cohort of acutely hospitalized disabled elderly patients whether total cholesterol predicts recovery from disability in basic activities of daily living (ADL). METHODS: Patients (3150) 65 years old or older admitted to 81 acute care units in Italy and presenting with ADL disability at hospital admission were included in this study. ADL disability was defined as need of assistance or total dependence in one or more ADLs (eating, dressing, personal hygiene, transferring, and toilet use). Recovery was defined as no disability at hospital discharge in any of the five ADLs considered. RESULTS: Mean age of study participants was 80.5 +/- 7.2 years, and 1305 (41.1%) were men. The rate of recovery from ADL disability was 14.5% for participants with total cholesterol or = 240 mg/dL (n = 76/329). After adjustment for potential confounders, relative to that of patients with cholesterol or = 240 mg/dL. After exclusion of 769 patients with total cholesterol or = 240 mg/dL. CONCLUSIONS: Among hospitalized disabled older adults, elevated levels of cholesterol are associated with increased rate of recovery from ADL disability