Postprandial Hypotension due to a Lack of Sympathetic Compensation in Patients with Diabetes Mellitus.

Postprandial hypotension is an important hemodynamic abnormality in diabetes mellitus, but few reports are available on the relationship between autonomic dysfunction and postprandial hypotension. Ten diabetic patients and 10 healthy volunteers were recruited for this study. Postural blood pressure and heart rate changes were measured before lunch, and then the hemodynamic responses to a standardized meal were investigated. Holter electrocardiogram (ECG) monitoring was conducted for assessing spectral powers and time-domain parameters of RR variations. Postural changes from the supine to the upright position decreased the systolic blood pressure of the diabetics from 133(+-)16 to 107(+-)20 mmHg (p<0.01), but did not decrease the systolic blood pressure of the controls. The heart rate remained constant in the diabetics but was increased in the controls. Food ingestion decreased systolic blood pressure in the diabetics, with a maximum reduction of 25(+-)5 mmHg. This decrease was not associated with any changes in the ratio of low frequency to high frequency, and yet the heart rate remained almost constant. Indexes involving parasympathetic tone were not affected. Food ingestion did not affect blood pressure in the control group. These findings suggest that lack of compensatory sympathetic activation is a factor contributing to postprandial hypotension in diabetics, and that parasympathetic drive does not make a significant contribution to this condition

Assessment of hydrogen embrittlement behavior in Al-Zn-Mg alloys by multi- modal 3D image-based simulation

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Prevention of hydrogen embrittlement in Al-Zn-Mg alloys by dispersion of novel phases

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Discovery of primitive CO2-bearing fluid in an aqueously altered carbonaceous chondrite

隕石中に閉じ込められたCO2に富む液体の水を世界で初めて発見 --太陽系形成時に誕生した小天体がその後の木星の軌道変化に伴なって移動した証拠--. 京都大学プレスリリース. 2021-04-22.Water is abundant as solid ice in the solar system and plays important roles in its evolution. Water is preserved in carbonaceous chondrites as hydroxyl and/or H₂O molecules in hydrous minerals, but has not been found as liquid. To uncover such liquid, we performed synchrotron-based x-ray computed nanotomography and transmission electron microscopy with a cryo-stage of the aqueously altered carbonaceous chondrite Sutter’s Mill. We discovered CO₂-bearing fluid (CO₂/H₂O > ~0.15) in a nanosized inclusion incorporated into a calcite crystal, appearing as CO₂ ice and/or CO₂ hydrate at 173 K. This is direct evidence of dynamic evolution of the solar system, requiring the Sutter’s Mill’s parent body to have formed outside the CO₂ snow line and later transportation to the inner solar system because of Jupiter’s orbital instability

Application of Scanning-Imaging X-Ray Microscopy to Fluid Inclusion Candidates in Carbonates of Carbonaceous Chondrites

In order to search for such fluid inclusions in carbonaceous chondrites, a nondestructive technique using x-ray micro-absorption tomography combined with FIB sampling was developed and applied to a carbonaceous chondrite. They found fluid inclusion candidates in calcite grains, which were formed by aqueous alteration. However, they could not determine whether they are really aqueous fluids or merely voids. Phase and absorption contrast images can be simultaneously obtained in 3D by using scanning-imaging x-ray microscopy (SIXM). In refractive index, n=1-sigma+i(beta), in the real part, 1-sigma is the refractive index with decrement, sigma, which is nearly proportional to the density, and the imaginary part, beta, is the extinction coefficient, which is related to the liner attenuation coefficient, mu. Many phases, including water and organic materials as well as minerals, can be identified by SIXM, and this technique has potential availability for Hayabusa-2 sample analysis too. In this study, we examined quantitative performance of d and m values and the spatial resolution in SIXM by using standard materials, and applied this technique to carbonaceous chondrite samples. We used POM ([CH2O]n), silicon, quartz, forsterite, corundum, magnetite and nickel as standard materials for examining the sigma and mu values. A fluid inclusion in terrestrial quartz and bi-valve shell (Atrina vexillum), which are composed of calcite and organic layers with different thickness, were also used for examining the spatial resolution. The Ivuna (CI) and Sutter's Mill (CM) meteorites were used as carbonaceous chondrite samples. Rod- or cube-shaped samples 20-30 micron in size were extracted by using FIB from cross-sectional surfaces of the standard materials or polished thin sections of the chondrites, which was previously observed with SEM. Then, the sample was attached to a thin W-needle and imaged by SIXM system at beamline BL47XU, SPring-8, Japan. The slice thickness was 109.3 nm and the pixel size was mostly 100 nm