Synthesis of crystalline microporous Mo−V−Bi oxide for selective (Amm)oxidation of light alkanes

Bismuth (Bi) was successfully introduced into the crystalline orthorhombic Mo3VOx (MoVO) structure for the first time by using the ethylammonium cation (EtNH3+) as a structure-directing agent in hydrothermal synthesis, and the catalytic activities of MoVO-containing Bi (MoVBiO) for selective oxidation of ethane and ammoxidation of propane were compared with those of ternary MoVO. Bi and EtNH3+ were located in hexagonal and heptagonal channels in the MoVO structure, respectively. EtNH3+ could be removed without collapse of the crystal structure by appropriate heat treatment, leaving the heptagonal channels empty. The introduction of Bi had only a little effect on the catalytic activity for selective oxidation of ethane. On the other hand, the conversion of propane was significantly enhanced in propane ammoxidation. Acrylonitrile selectivity was also enhanced by the introduction of Bi, especially at high temperatures (>440 °C)

ダパグリフロジン投与における肥満２型糖尿病患者の治療満足度への影響：a patient reported outcome study (PRO study).

Background: The benefits of sodium glucose cotransporters 2 (SGLT2) inhibitors in patients with type 2 diabetes mellitus include plasma glucose control, reduction in body weight and blood pressure, and low risk of hypoglycemia, although they may also cause genitourinary infections, polyuria, or volume depletion. It is not clear whether dapagliflozin, an SGLT2 inhibitor, improves treatment satisfaction among patients in a comprehensive way despite the negative side effects. This study assessed the effect of dapagliflozin on glycosylated hemoglobin (HbA1c), body weight, and treatment satisfaction in overweight patients with type 2 diabetes mellitus treated with oral hypoglycemic agents. Methods: This multicenter, open-label, single-arm observational study included patients with type 2 diabetes mellitus administering dapagliflozin 5 or 10 mg per day for 14 weeks. Changes in treatment satisfaction were evaluated using a new version of the Oral Hypoglycemic Agent-Questionnaire (OHA-Q ver. 2) consisting of 23 items. Correlation between treatment satisfaction and HbA1c levels and body weight were analyzed using the Spearman's rank-correlation coefficient. Results: Of the 221 patients enrolled, 188 completed the study. Mean HbA1c decreased from 7.8 ± 0.7% (62.1 ± 7.5 mmol/mol) to 7.3 ± 0.8% (55.9 ± 8.7 mmol/mol) (change - 0.6 ± 0.7%, P < 0.001) and body weight decreased from 82.5 ± 14.6 to 80.7 ± 14.8 kg (change - 2.3 ± 2.8 kg, P < 0.001). OHA-Q ver. 2 was validated as well, the mean OHA-Q ver. 2 total score increased from 44.3 ± 9.4 to 46.6 ± 9.8 (best score 69, worst score 0; change 2.3 ± 6.6, P < 0.001). The change in body weight significantly correlated with the OHA-Q ver. 2 total score (Spearman's ρ = - 0.17, P = 0.035). The change in HbA1c levels significantly correlated with the satisfaction subscale score (Spearman's ρ = - 0.19, P = 0.011). Conclusions: Dapagliflozin significantly improved treatment satisfaction among patients with type 2 diabetes mellitus for 14 weeks. Body weight loss significantly correlated with treatment satisfaction.Trial registration UMIN-CTR: UMIN000016304.博士（医学）・甲第694号・平成31年3月15日© The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

Impacts of recombination at the surface and in the substrate on carrier lifetimes of n-type 4H–SiC epilayers

After remarkable reduction in the Z1/2 center in n-type 4H–SiC epilayers, the measured carrier lifetimes can be severely affected by other recombination paths. Impacts of carrier recombination at the surface as well as in the substrate are investigated in detail by using numerical simulation based on a diffusion equation. The simulation reveals that a very thick (>100 μm) epilayer is required for accurate measurement of carrier lifetimes if the bulk lifetime in the epilayer is longer than several microsecond, due to the extremely short lifetimes in the substrate. The fast decay often observed at the initial stage of decay curves can be explained by fast recombination at the surface and in the substrate. In experiments, the carrier lifetime is improved from 0.69 to 9.5 μs by reducing the Z1/2 center via two-step thermal treatment (thermal oxidation and Ar annealing) for a 148-μm-thick n-type epilayer. This lifetime must be still, to large extent, affected by the recombination at the surface and in the substrate, and the real bulk lifetime may be much longer. The carrier recombination paths and their impacts on the decay curves are discussed

Simulation and experimental study on the junction termination structure for high-voltage 4H-SiC PiN diodes

Designing and fabrication of 10-kV 4H-SiC PiN diodes with an improved junction termination structure have been investigated. An improved bevel mesa structure and a single-zone junction termination extension (JTE) have been employed to achieve a high breakdown voltage (ges 10 kV). The improved bevel mesa structure, nearly a vertical sidewall at the edge of the p-n junction and a gradual slope at the mesa bottom, has been fabricated by reactive ion etching. The effectiveness of the improved bevel mesa structure has been experimentally demonstrated. The JTE region has been optimized by device simulation, and the JTE dose dependence of the breakdown voltage has been compared with experimental results. A 4H-SiC PiN diode with a JTE dose of 1.1 times 1013 cm-2 has exhibited a high blocking voltage of 10.2 kV. The locations of electric field crowding and breakdown are also discussed

Simulation and experimental study on the junction termination structure for high-voltage 4H-SiC PiN diodes

Designing and fabrication of 10-kV 4H-SiC PiN diodes with an improved junction termination structure have been investigated. An improved bevel mesa structure and a single-zone junction termination extension (JTE) have been employed to achieve a high breakdown voltage (ges 10 kV). The improved bevel mesa structure, nearly a vertical sidewall at the edge of the p-n junction and a gradual slope at the mesa bottom, has been fabricated by reactive ion etching. The effectiveness of the improved bevel mesa structure has been experimentally demonstrated. The JTE region has been optimized by device simulation, and the JTE dose dependence of the breakdown voltage has been compared with experimental results. A 4H-SiC PiN diode with a JTE dose of 1.1 times 1013 cm-2 has exhibited a high blocking voltage of 10.2 kV. The locations of electric field crowding and breakdown are also discussed