High-energy-resolution core-level and valence-band photoelectron spectroscopic studies were performed for the heavy Fermion uranium compounds UGe2, UCoGe, URhGe, URu2Si2, UNi2Al3, UPd2Al3, and UPt3 as well as typical localized and itinerant uranium compounds to understand the relationship between the uranium valence state and their core-level spectral line shapes. In addition to the main line and high-binding energy satellite structure recognized in the core-level spectra of uranium compounds, a shoulder structure on the lower binding energy side of the main lines of localized and nearly localized uranium compounds was also found. The spectral line shapes show a systematic variation depending on the U 5f electronic structure. The core-level spectra of UGe2, UCoGe, URhGe, URu2Si2, and UNi2Al3 are rather similar to those of itinerant compounds, suggesting that U 5f electrons in these compounds are well hybridized with ligand states. On the other hand, the core-level spectra of UPd2Al3 and UPt3 show considerably different spectral line shapes from those of the itinerant compounds, suggesting that U 5f electrons in UPd2Al3 and UPt3 are less hybridized with ligand states, leading to the correlated nature of U 5f electrons in these compounds. The dominant final state characters in their core-level spectra suggest that the numbers of 5f electrons in UGe2, UCoGe, URhGe, URu2Si2, UNi2Al3, and UPd2Al3 are close to but less than three, while that of UPt3 is close to two rather than to three.
The purpose of this study was to examine the hemodynamic characteristics of expanded polytetrafluoroethylene (ePTFE) pulmonary valves with bulging sinuses quantitatively in a pediatric pulmonary mechanical circulatory system designed by us, in order to propose the optimal design for clinical applications. In this study, we developed a pediatric pulmonary mock circulation system, which consisted of a pneumatic right ventricular model, a pulmonary heart valve chamber, and a pulmonary elastic compliance tubing with resistive units. The hemodynamic characteristics of four different types of ePTFE valves and a monoleaflet mechanical heart valve were examined. Relationships between the leaflet movements and fluid characteristics were evaluated based on engineering analyses using echocardiography and a high-speed video camera under the pediatric circulatory conditions of the mock system. We successfully performed hemodynamic simulations in our pediatric pulmonary circulatory system that could be useful for quantitatively evaluating the pediatric heart valves. In the simulation study, the ePTFE valve with bulging sinuses exhibited a large eddy in the vicinity of the leaflets, whereas the straight tubing exhibited turbulent flow. The Reynolds number obtained in the valve with bulging sinuses was calculated to be 1667, which was smaller than that in the straight tubing (R (e) = 2454).The hemodynamic characteristics of ePTFE pediatric pulmonary heart valves were examined in our mock circulatory system. The presence of the bulging sinuses in the pulmonary heart valve decreased the hydrodynamic energy loss and increased the systolic opening area. Based on an in vitro experiment, we were able to propose an optimal selection of pulmonary valve design parameters that could yield a more sophisticated pediatric ePTFE valve shape.
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