Effect of the surface morphology of alkaline-earth metal oxides on the oxidative coupling of methane.

Alkaline-earth metal oxides with the rocksalt structure, which are simple ionic solids, have attracted attention in attempts to gain fundamental insights into the properties of metal oxides. The surfaces of alkaline-earth metal oxides are considered promising catalysts for the oxidative coupling of methane (OCM); however, the development of such catalysts remains a central research topic. In this paper, we performed first-principles calculations to investigate the ability of four alkaline-earth metal oxides (MgO, CaO, SrO, and BaO) to catalyze the OCM.

Delayed Tension Hemothorax With Nondisplaced Rib Fractures After Blunt Thoracic Trauma.

Blunt thoracic trauma often causes rib fractures, hemothorax, and pneumothorax. Although there is no established definition regarding the duration and management of delayed hemothorax, it commonly occurs in a few days and exhibits at least one displaced rib fracture. Moreover, delayed hemothorax rarely develops tension hemothorax.

Conformational characteristics and conformation-dependent properties of poly(ε-caprolactone).

Structures and properties of isolated and crystalline poly(ε-caprolactone) (PCL) chains have been investigated. molecular orbital (MO) calculations were conducted for methyl 6-acetoxyhexanoate (MAH), a model compound of PCL, to yield Gibbs free energies of all its existent conformers. Bond conformations of its seven bonds corresponding to the repeating unit of PCL were calculated therefrom; two C-C bonds close to the ester group show preferences owing to intramolecular C-H⋯O attractions, and the other five prefer forms.

Risk factors for prolonged ventilation after the modified Fontan procedure.

Objective: To investigate the risk factors associated with prolonged ventilation after Fontan surgery.

Design: Retrospective case series.

Setting: Tertiary childrens hospital.