Alcohol Self-Aggregation: the Preferred Configurations of the Ethanol Trimer.

An atomic-level knowledge of the aggregation of archetypal molecular systems is essential to accurately model supramolecular structures and the transition from gas to liquid phase. The structures and forces involved in ethanol aggregation have been investigated using microwave spectroscopy and extensive quantum chemical calculations. Four isomers of the ethanol trimer have been observed and identified based on comparisons between experimental and predicted spectroscopic parameters, and considering collisional relaxation in the supersonic expansion.

Reference values for respiratory muscle strength and maximal voluntary ventilation in the Brazilian adult population: A multicentric study.

Aim: To determine reference values and propose prediction equations for respiratory muscle strength, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and endurance by means of maximal voluntary ventilation (MVV) in healthy Brazilian adults.

Methods: Anthropometric data, level of physical activity, pulmonary function, and respiratory muscle strength and maximal voluntary ventilation of 243 participants (111 men and 132 women) aged 20 to 80 years were assessed at three cities in the southeast and northeast region of Brazil.

Results: Mean maximal respiratory pressures and MVV were higher in men (MIP = 111.

Unprecedented selectivity behavior in the direct dehydrogenation of -butane to -butenes with similar active Pt nanoparticle size: unveiling structural and electronic characteristics of supported monometallic catalysts.

In this work, supported Pt monometallic catalysts were prepared using oxide and carbon supports by conventional impregnation methods. Similar Pt metallic nanoparticle sizes (mean sizes about 1.8-2 nm) have been obtained using different Pt precursor loadings (0.

[Intentional search and reclassification of maternal deaths: quality information and its analysis to reduce maternal mortalityBusca intencional e reclassificação de mortes maternas: informação de qualidade e sua análise para reduzir a mortalidade materna].

Objective: To describe the methodology of the intentional search and reclassification of maternal deaths (BIRMM, acronym in Spanish), which allows the identification and correction of misclassification and underreporting of maternal deaths.

Methods: The BIRMM methodology, initially developed in Mexico in 2003 and disseminated in other Latin American countries since 2012, was used. BIRMM consists of four key components: i) reclassification of confirmed maternal deaths; ii) identification and investigation of suspected cases of maternal death; iii) cross-referencing with other information sources; and iv) publication of results and statistical analysis.

Hydride and halide abstraction reactions behind the enhanced basicity of Be and Mg clusters with nitrogen bases.

In this study, we investigate the protonation effects on the structure, relative stability and basicity of complexes formed by the interaction of monomers and dimers of BeX and MgX (X = H, F) with NH, CHNH, HCN, and NCH bases. Calculations were performed using the M06-2X/aug-cc-pVTZ formalism, along with QTAIM, ELF and NCI methods for electron density analysis and MBIE and LMO-EDA energy decomposition analyses for interaction enthalpies. The protonation of the MH- and MH-Base complexes occurs at the negatively charged hydrogen atoms of the MH and MH moieties through typical hydride abstraction reactions, while protonation at the N atom of the base is systematically less exothermic.