Direct Experimental Evidence for Markedly Enhanced Surface Proton Activity Inherent to Water Ice

Autoionization and subsequent proton transfer processes determine the proton activity inherent to water molecular systems. In this study, we provide direct experimental evidence that the proton activity is markedly enhanced at the surface of crystalline ice, on the basis of the simultaneous observation of H/D exchange of water molecules at the surface and in the interior of well-defined double-layer ice films composed of H2O and D2O. Thermal desorption mass spectrometry showed clear signatures derived from the surface H/D exchange equilibrium, whereas infrared absorption spectroscopy indicated no appreciable H/D exchange progress in the interior. Detailed kinetic analyses revealed that the rate of H/D exchange at the surface is at least 3 orders of magnitude higher than in the interior. This drastic enhancement of the proton activity suggests an extremely high concentration of surface-hydrated protons in comparison with those in the bulk. Our results also highlight the impact of the local hydrogen-bond structure on the autoionization of water molecules

Fabrication and Thermoelectric Properties of Freestanding Ba_1/3CoO₂ Single-Crystalline Films

Thermoelectric energy conversion has attracted attention as an energy-harvesting technology for converting waste heat into electricity via the Seebeck effect. Conducting oxide-based thermoelectric materials that exhibit a high figure of merit are promising because of their good chemical and thermal stability as well as their harmless nature compared to chalcogenide-based state-of-the-art thermoelectric materials. Among many conducting oxides, Ba1/3CoO2 epitaxial films exhibit the highest figures of merit. For the practical use of Ba1/3CoO2, bulk ceramics or single-crystalline Ba1/3CoO2 is necessary. Here, we show that freestanding Ba1/3CoO2 single-crystalline films can be fabricated by peeling Ba1/3CoO2 epitaxial films from the substrate. We fabricated Ba1/3CoO2 epitaxial films and immersed them in 40 °C hot water for several tens of minutes. Subsequently, the Ba1/3CoO2 epitaxial film spontaneously peeled off and floated on the surface of the water like seaweed. We measured and analyzed the crystal structure, chemical composition, and thermoelectric properties before and after peeling and realized that there was no significant difference. The present results provide a useful method for fabricating freestanding single-crystalline oxide films for thermoelectrics

Correlation between mean obstruction ratio and PaO₂.

The mean obstruction ratio was negatively correlated with postoperative (A) and follow-up (B) PaO2. However, no correlation was observed between the mean obstruction ratio and preoperative PaO2 (C).</p

Severe Pulmonary Arteriopathy Is Associated with Persistent Hypoxemia after Pulmonary Endarterectomy in Chronic Thromboembolic Pulmonary Hypertension

<div><p>Background</p><p>Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by occlusion of pulmonary arteries by organized chronic thrombi. Persistent hypoxemia and residual pulmonary hypertension (PH) following successful pulmonary endarterectomy (PEA) are clinically important problems; however, the underlying mechanisms remain unclear. We have previously reported that residual PH is closely related to severe pulmonary vascular remodeling and hypothesize that this arteriopathy might also be involved in impaired gas exchange. The purpose of this study was to evaluate the association between hypoxemia and pulmonary arteriopathy after PEA.</p><p>Methods and Results</p><p>Between December 2011 and November 2014, 23 CTEPH patients underwent PEA and lung biopsy. The extent of pulmonary arteriopathy was quantified pathologically in lung biopsy specimens. We then analyzed the relationship between the severity of pulmonary arteriopathy and gas exchange after PEA. We observed that the severity of pulmonary arteriopathy was negatively correlated with postoperative and follow-up PaO₂ (postoperative PaO₂: r = -0.73, p = 0.0004; follow-up PaO₂: r = -0.66, p = 0.001), but not with preoperative PaO₂ (r = -0.373, p = 0.08). Multivariate analysis revealed that the obstruction ratio and patient age were determinants of PaO₂ one month after PEA (R² = 0.651, p = 0.00009). Furthermore, the obstruction ratio and improvement of pulmonary vascular resistance were determinants of PaO₂ at follow-up (R² = 0.545, p = 0.0002). Severe pulmonary arteriopathy might increase the alveolar-arterial oxygen difference and impair diffusion capacity, resulting in hypoxemia following PEA.</p><p>Conclusion</p><p>The severity of pulmonary arteriopathy was closely associated with postoperative and follow-up hypoxemia.</p></div

Univariate and multivariate analysis of variables associated with follow-up PaO₂.

<p>Univariate and multivariate analysis of variables associated with follow-up PaO₂.</p

Relationship between the mean obstruction ratio and %DL_CO/V_A.

<p>The mean obstruction ratio was negatively correlated with postoperative (A) and follow-up %DL_CO/V_A (B). However, the mean obstruction ratio did not correlate with preoperative %DL_CO/V_A (C). The high obstruction group had lower %DL_CO/V_A values than the low-obstruction group (p = 0.002, analyzed by repeated measures ANOVA) (D). (*: p<0.05, vs preoperative data for each group; §: p<0.05, vs postoperative data for each group).</p

Univariate and multivariate analysis of variables associated with postoperative PaO₂.

<p>Univariate and multivariate analysis of variables associated with postoperative PaO₂.</p

Pulmonary arteriopathy in biopsied lung tissues.

<p>Severe pulmonary arteriopathy in the high-obstruction group (A). Pulmonary arteriopathy was composed of severe fibrous intimal thickening, moderate medial hypertrophy, and lumen stenosis. The low-obstruction group (B) demonstrated mild pulmonary intimal thickening and medial hypertrophy.</p

Patient characteristics.

<p>Patient characteristics.</p

Relationship between mean obstruction ratio and A-aDO₂.

<p>The mean obstruction ratio was negatively correlated with the preoperative (A), postoperative (B), and follow-up A-aDO₂ (C). The high obstruction group had higher A-aDO₂ values than the low-obstruction group (p = 0.004, analyzed by repeated measures ANOVA) (D).</p