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Background The cuff pressures may be different in oesophageal and tracheal intubations. We conducted a study to evaluate if cuff pressures of endotracheal tubes (ETTs) could provide information to distinguish tracheal or oesophageal intubations in a pig trachea–oesophagus model. Methods In each preparation of pig trachea–oesophagus model, the trachea and the oesophagus were intubated separately with a cuffed ETT, and the cuff pressures were measured after each 1 ml increment of air (1–10 ml) during inflation. The cuff pressures and the pressure–volume relationships in both intubations were compared. Results The cuff pressures of oesophageal intubations were significantly higher than those of tracheal intubations in all comparisons from 1 to 10 ml of cuff volumes (P Conclusions We conclude that the cuff pressures may be useful in detecting oesophageal intubations. This method is faster than other confirmation measures as it can detect inadvertent oesophageal intubations at the time of inflating the cuffs. [ABSTRACT FROM AUTHOR]

The physical properties of Sr14−xCaxCu24O41 are determined by the hole distribution between the edge-shared CuO2 chain and the corner-shared Cu2O3 two-leg ladder, but inconsistent results on the hole distribution were obtained in various experimental works in recent decades. In this work we reinvestigate the hole distribution by soft x-ray absorption spectroscopy at the Cu L3 edge. By comparing with the pure ladder and the pure chain systems, we can unambiguously distinguish between the hole distributions in the chain and the ladder. We have found that there are 5.3 holes in the edge-shared chain and 0.7 holes in the corner-shared ladder on average for Sr14Cu24O41. Upon Ca substitution, the holes gradually transfer from the edge-shared chain to the corner-shared ladder, and there are up to 1.21 holes in the corner-shared ladder for Sr1.8Ca12.2Cu24O41. [ABSTRACT FROM AUTHOR]

Using atomically resolved electron energy-loss spectroscopy, the atomic-plane-by-atomic-plane, unit-cell-by-unit-cell stoichiometry, and charge characteristics of the oxide interface (Nd0.35Sr0.65)MnO3/SrTiO3, with a primitive polar discontinuity of (Nd0.35Sr0.65O)0.35+-(TiO2)0, were thoroughly investigated. (Nd0.35Sr0.65O)MnO3 is a strongly correlated insulator and the interface was characterized to be insulating. The cell-specific stoichiometric evaluation unveiled an extensive interdiffusion across the interface. The plane-specific charge characterization revealed that the interdiffusion grades the primitive polar discontinuity. Despite the graded polar discontinuity, a charge transfer inversely into (Nd0.35Sr0.65O)MnO3 was firmly resolved with a length scale of ∼2 nm and a charge density on the order of ∼1013/cm2 and is effectively mediated by an asymmetric Ti interdiffusion. The intricate electronic correlations of the interfacial (Nd0.35Sr0.65O)MnO3 unit cells and the interdiffusion-induced chemical disorder tend to render the charges localized, resulting in a localized two-dimensional electron density and thus the insulating interface, in distinct contrast to the conventional understanding of a vanishing charge density for an insulating interface and the metallic two-dimensional electron gas found at other classical polar-discontinuous interface systems. A potential strain manipulation on the electronic localization of the electron density was also proposed. [ABSTRACT FROM AUTHOR]