Aim: The cardio–ankle vascular index (CAVI) represents the blood pressure-independent arterial stiffness from the origin of the aorta to the ankle. CAVI0 has been proposed as a variant index. We ...aimed to clarify the difference between CAVI and CAVI0 among large populations, and to explore reasons of the difference.Methods: The subjects were 5,293 Japanese healthy and 3,338 hypertensive people. Simple and multiple regression analyses were performed using age, sex, body mass index, systolic, and diastolic blood pressure (Pd) as variables. Sub-group analysis was performed by sex and age. The CAVI values with and without adjustment by reference pressure were also compared.Results: CAVI had a positive correlation with Pd, while CAVI0 had a negative correlation with Pd in the healthy population. The CAVI values of the hypertensive group were higher than those of healthy group in both men and women, but the CAVI0 values in women of the hypertensive group in the 30–39 age group was significantly lower than that of the corresponding healthy group. Differences of CAVI values with or without modification using the reference pressure were 1.09%±1.38% for the healthy group and 3.68%±1.66% for the hypertensive group.Conclusion: CAVI showed the expected values, but CAVI0 showed inexplicable results in the healthy and hypertensive populations. The differences were due to the strong dependency of CAVI0 on Pd. Differences of CAVI values with or without reference pressure were negligible. These results indicate that CAVI obtained by the VaSera system is appropriate, but CAVI0 is not.
Numerous attempts have been made to improve the oxidation resistance and electrical conductivity of the interconnectors in solid oxide fuel cells. A Co–W alloy coating on ferritic stainless steel has ...attracted attention because the Co–W oxide layer formed by the oxidation treatment of the Co–W alloy coating has proven effective in reducing the outward diffusion of Cr and improving oxidation resistance. This study was designed to elucidate the diffusion behavior of elements and the barrier mechanism of the CoWO4 layer. After oxidation in air at 750°C, a dense, multilayered oxide formed, comprising (from the stainless steel substrate to the outer layer) Cr2O3, (Cr,Fe,Co)3O4, CoWO4, (Co,Fe)3O4, and Co3O4 layers. The CoWO4 layer and neighboring oxide layers were carefully analyzed by scanning electron microscopy and transmission electron microscopy with electron energy-loss spectroscopy, confirming the absence of trivalent cations (Co3+, Fe3+, and Cr3+) and the presence of Fe2+ ions in the CoWO4 layer; thus, CoWO4 functions as a selective diffusion barrier to trivalent cations, as hypothesized. The Cr-containing oxide layer grows based on the reaction between the metallic cations from the substrate and the inward-diffusing oxide ions, whereas Fe and Co can diffuse outward through CoWO4 as Fe2+ and Co2+ ions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The experimental evidence for the contraction of volume of gold implanted with hydrogen at low doses is presented. The contraction of lattice upon the addition of other elements is very rare and ...extraordinary in the solid-state, not only for gold but also for many other solids. To explain the underlying physics, the pure kinetic theory of absorption is not adequate and the detailed interaction of hydrogen in the lattice needs to be clarified. Our analysis points to the importance of the formation of hydride bonds in a dynamic manner and explains why these bonds become weak at higher doses, leading to the inverse process of volume expansion frequently seen in metallic hydrogen containers.
Aim: Stroke is well known to lead to hypertension; nevertheless, the role of vascular function in hypertension remains unclear. In this study, we aimed to clarify the mechanism underlying increased ...arterial stiffness following stroke. Methods: The cardio-ankle vascular index (CAVI) was measured in five New Zealand White rabbits. Under general anesthesia, intracranial pressure (ICP) was increased by injecting saline (15 mL) into the cisterna magna. ICP was monitored using a catheter inserted into the subarachnoid space via right frontal bone craniotomy. Blood pressure (BP), CAVI, and common carotid flow (CCF) were evaluated, and the responses of these parameters to increased ICP were analyzed. Results: Saline injection into the cisterna magna increased the ICP by over 20 mmHg. Both BP and CAVI increased from 63.2±4.84 to 128.8±14.68 mmHg and from 4.02±0.28 to 4.9±0.53, respectively. Similarly, BP and CCF increased. When hexamethonium was administered before the increase in ICP, the increase in BP (132.2±9.41 mmHg with 10 mg/kg hexamethonium vs. 105.6±11.01 mmHg with 100 mg/kg hexamethonium) and CAVI (5.02±0.64 with 10 mg/kg hexamethonium vs. 4.82±0.42 with 100 mg/kg hexamethonium) were suppressed in a dose-dependent manner. Conclusion: Increased ICP causes an increase in BP and CAVI, suggesting that enhanced stiffness of the muscular arteries contributes to high BP. Blocking the autonomic nervous system with hexamethonium suppresses the increase in BP and CAVI, indicating that these increases are mediated by activation of the autonomic nervous system.
Aim: The Cardio-Ankle Vascular Index (CAVI) is a stiffness index of the arterial tree from the origin of the aorta to the ankle, independent of blood pressure at the time of measurement. The CAVI ...equation includes the coefficients “a” and “b” to adjust it to the value of Hasegawa’s pulse wave velocity, which is compensated for at 80 mmHg of diastolic pressure. To verify this adjustment with the coefficients, the clinical significance of CAVI and CAVI without the coefficients (haβ) were compared in both an epidemiological study and an acute clinical study.Methods: In the epidemiological study, the significances of CAVI and haβ among people with or without coronary risks such as hypertension, dyslipidemia, hyperglycemia, and abnormal electrocardiography change, were compared. In the acute clinical study, nitroglycerin was administered to subjects in a control group and to coronary artery disease patients, observing CAVI and haβ values over a 20-min period.Results: There was no discrepancy in terms of statistically significant differences between CAVI and haβ among subjects with or without risk factors. Furthermore, there was also no discrepancy in terms of statistically significant differences between CAVI and haβ during the changes of those values following nitroglycerin administration over a 20-min period.Conclusion: In both the epidemiologic and clinical studies, there was no discrepancy in terms of significant differences between CAVI and haβ. These results suggest that both are valid as indices of stiffness of the arterial tree from the origin of the aorta to the ankle.
This study aims to establish a test method for loading test tracks composed of a single set of rail fastenings for rail joints. The authors of this paper constructed FEM models for railway tracks ...which represent rail joint parts accurately and performed an FEM analysis. The FEM results are in good agreement with the results of a load test on a test track composed of multiple sets of rail fastenings. On the basis of the FEM model, the authors proposed a test method for loading test tracks composed of a single set of rail fastenings and compared the test results of a single set of rail fastenings with those of multiple sets of rail fastenings. The results show that rail head displacements and rail tilting angles obtained by a single set of rail fastenings are in good agreement with those obtained by multiple sets of rail fastenings. Therefore, it is concluded that the proposed method based on the FEM model is able to evaluate the performance of rail fastening systems for rail joints.
Lead halide perovskite single layers with three grain sizes are subjected to proton-beam irradiation in order to assess the durability and radiation tolerance of perovskite solar cells (PSCs) against ...space radiation. Proton-beam irradiation is chosen because proton beams significantly affect solar cell performance in the space environment. We evaluate the effects of proton beams by focusing on the grain structure, crystal structure, and carrier lifetime of a perovskite single layer by using scanning electron microscopy, X-ray diffraction, photoluminescence (PL) spectra, and time-resolved PL (TRPL). The results show that proton irradiation does not significantly affect the grain structure and crystal structure of perovskite layer; the TRPL results show that the carrier lifetime inside the grain is constant up to a fluence of 1 × 1014 p+/cm2 and decreases significantly at a fluence of 1 × 1015 p+/cm2. Proton-beam radiation tolerance of the grain inside the perovskite layer is dominant in the radiation tolerance of PSCs.
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IJS, KILJ, NUK, PNG, UL, UM
This study aims to establish a loading test method on test tracks composed of a single rail fastening at rail joints. The authors construct FEM models for railway tracks which represent the rail ...joint parts accurately and perform the FEM analysis. The FEM results are in good agreements with the results of a loading test on a test track composed of plural rail fastenings. Based on the FEM model, the authors proposed the loading test method on test tracks composed of a single rail fastening and compared the test results of a single rail fastening and plural rail fastenings. As a results, it becomes clear that rail head displacements and rail tilting angles obtained from a single rail fastening are in good agreement with those obtained from the plural rail fastenings. Therefore the proposed method of loading test on a test track composed of a single rail fastening based on the FEM model is available to evaluate the performance of the rail fastenings systems of rail joints.
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