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

Clinical Studies on Gout 2nd Report: Statistical Observation on Gouty Arthritis in Japan

The authors gathered 78 cases of gouty arthritis reported in Japan between 1898 and 1960, and analysed them statistically. 1. The incidence of gouty arthritis appears to have increased since about the end of the 2nd World War, especially since 1955. 2. The age of the presumptive onset of the disease is lower in Japanese than in white populations. 3. In many cases, the gouty patients were wrongly diagnosed as rheumatoid arthritis, synovitis or panaritium patients, and only 20 per cent of the cases examined were diagnosed correctly at the first consultation. The author stresses that diagnosis at an early stage is necessary to avoid serious complications such as cardiovascular and renal involvements. If the condition is satisfactorily controlled by diets and drugs, however, the prognosis for gouty patients is excellent

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

Effects of Low-Dose Non-Caloric Sweetener Consumption on Gut Microbiota in Mice

Non-caloric artificial sweeteners (NASs) provide sweet tastes to food without adding calories or glucose. NASs can be used as alternative sweeteners for controlling blood glucose levels and weight gain. Although the consumption of NASs has increased over the past decade in Japan and other countries, whether these sweeteners affect the composition of the gut microbiome is unclear. In the present study, we examined the effects of sucralose or acesulfame-K ingestion (at most the maximum acceptable daily intake (ADI) levels, 15 mg/kg body weight) on the gut microbiome in mice. Consumption of sucralose, but not acesulfame-K, for 8 weeks reduced the relative amount of Clostridium cluster XIVa in feces. Meanwhile, sucralose and acesulfame-K did not increase food intake, body weight gain or liver weight, or fat in the epididymis or cecum. Only sucralose intake increased the concentration of hepatic cholesterol and cholic acid. Moreover, the relative concentration of butyrate and the ratio of secondary/primary bile acids in luminal metabolites increased with sucralose consumption in a dose-dependent manner. These results suggest that daily intake of maximum ADI levels of sucralose, but not acesulfame-K, affected the relative amount of the Clostridium cluster XIVa in fecal microbiome and cholesterol bile acid metabolism in mice

Needle Tract Ablation in Liver Tissue Using a Cryoprobe Combined with an Electrosurgical Device: Influence of ex vivo and in vivo Animal Models

To assess the feasibility of needle tract ablation in liver tissue in ex vivo and in vivo animal models using a cryo-probe and electrosurgical device. The experimental device is made by inserting a cryoprobe through an intro-ducer sheath for insulation, with 2-cm of probe tip projecting out. A beagle liver was punctured by the device, and electric current was applied at 30-W with the electrosurgical knife touching the non-insulated device base. The discolored area of cut surface along the device was evaluated in 5 application-time groups (5 , 10 , 15 , 20, or 25 seconds). An ex vivo experiment was performed to determine an ablation algorithm with an appropriate application time by comparison with radiofrequency ablation (RFA) results. Thereafter, an in vivo experiment was performed to verify the algorithm’s feasibility. In the ex vivo model, the cut surface demonstrated different amounts of discolored area according to the application time. The total discolored area in the 20-seconds group was similar to that by RFA. In the in vivo model, the liver did not bleed, the total discolored area was similar to that ex vivo, and coagulation necrosis was confirmed by photomicrograph. Needle tract ablation can be per-formed using the experimental device and electrosurgical device

CT画像を用いて算出したHip Structural Analysis(HSA)指標の検討

骨粗鬆症に伴う脆弱性骨折を起こすか否かは,骨量,骨構造,骨の石灰化,ダメージの蓄積および骨代謝などに依存するとされているが,近年,骨量測定に臨床で広く用いられているDXA装置に大腿骨近位部の構造力学的解析が可能なHip Structural Analysis (HSA) のプログラムが組み込まれ,骨強度の評価に用いられている.そこで我々は,CT画像からHSA指標の算出が可能か否か,また,その手法による指標の計算精度について,DXA装置で得られた指標と比較することによって検討した.その結果,CT画像からHSA指標の算出は可能であったが,その計算精度に若干の問題があり,撮影時の整位および計算位置の解剖学的なズレ等を補正する必要があることがわかった

Microsoft Excelにおける2次元フーリエ変換を用いた画像処理法の構築

Microsoft Excelを用いて2次元高速フーリエ変換を行い,空間周波数領域で画像処理する方法の構築を目的とした.検討には,処理対象画像として胸部骨シンチグラム像を,解析アプリケーションソフトにはMicrosoft Excel 2007とImage Jをそれぞれ用いた.なお,Microsoft Excelでの高速フーリエ変換は,処理時間を短縮するためマクロを構築した.その結果,Microsoft Excelでの処理画像は,核医学のデータ処理専用装置のそれとの間に殆ど差が認められなかった.これにより,我々が構築したMicrosoft Excelを用いた画像処理法は,十分に使用可能なことが証明された