Interpretation of the expansion law of planetary nebulae

We reproduce the expansion velocity--radius ($V_{\rm{exp}}$--$R_{\rm{n}}$) relation in planetary nebulae by considering a simple dynamical model, in order to investigate the dynamical evolution and formation of planetary nebulae. In our model, the planetary nebula is formed and evolving by interaction of a fast wind from the central star with a slow wind from its progenitor, the AGB star. In particular, taking account of the mass loss history of the AGB star makes us succeed in the reproduction of the observed $V_{\rm{exp}}$-$R_{\rm{n}}$ sequence. As a result, examining the ensemble of the observational and theoretical evolution models of PNe, we find that if the AGB star pulsates and its mass loss rate changes with time (from $\sim 10^{-6.4}M_{\odot}$ yr$^{-1}$ to $\sim 10^{-5}M_{\odot}$ yr$^{-1}$), the model agrees with the observations. In terms of observation, we suggest that there are few planetary nebulae with larger expansion velocity and smaller radius because the evolutionary time-scale of such nebulae is so short and the size of nebulae is so compact that it is difficult for us to observe them.Comment: 16 pages, 18 figure1, PASJ in pres

Preparation of Ba1-xLnxFeO3-δ and BaFe1-xLnxO3-δ (Ln: trivalent ion) with cubic perovskite structure and random distribution of oxide ion vacancy

Oxides with perovskite structure and random arrangement of oxide ion, such as Ba0.5Sr0.5Fe0.2Co0.8O3-δ, attract much interest as oxygen permeation material. For wide spread of oxygen permeation devices, development of new material without Co is highly desired because of high cost of Co. Recently, we reported that arrangement of oxide ion vacancy in monoclinic BaFeO2.5-δ changes from ordered to random by partial La3+ substitution for Ba2+ site, resulting in cubic perovskite structure and improvement of electrical conductivity [1, 2]. Fujishiro reported preparation of BaFe1-xInxO3-δ with cubic perovskite structure and enhancement of electrical conductivity with In substitution [3]. It is expected that material with higher property may be developed by substitution of other trivalent ion, such as lanthanoid or Y, for Ba- or Fe- site in BaFeO2.5-δ. In this work, preparation of various Ba1-xLnxFeO3-δ and BaFe1-xLnxO3-δ (Ln: trivalent ion) was examined and factors determining substitution site and crystal structure were investigated. The samples of Ba1-xLnxFeO3-δ and BaFe1-xLnxO3-δ were prepared with Pechini method. Each solution of Ba2+, Ln3+ and Fe3+ was mixed with nominal cation composition. After addition of citric acid and ethylene glycol, the solution was heated at about 450 ºC, resulting in precursor. The precursor was calcined at 700 ºC for 24 h in air, followed by 1300 ºC for 10 h in air twice. The crystal structure and lattice constants of the specimens were investigated with X-ray diffraction. The chemical state of Fe and oxygen content of the specimens were evaluated with iodometric titration. Please click Additional Files below to see the full abstract

Inversion channel diamond metaloxide-semiconductor field-effect transistor with normally off characteristics

We fabricated inversion channel diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with normally off characteristics. At present, Si MOSFETs and insulated gate bipolar transistors (IGBTs) with inversion channels are widely used because of their high controllability of electric power and high tolerance. Although a diamond semiconductor is considered to be a material with a strong potential for application in next-generation power devices, diamond MOSFETs with an inversion channel have not yet been reported. We precisely controlled the MOS interface for diamond by wet annealing and fabricated p-channel and planar-type MOSFETs with phosphorus-doped n-type body on diamond (111) substrate. The gate oxide of Al2O3 was deposited onto the n-type diamond body by atomic layer deposition at 300 °C. The drain current was controlled by the negative gate voltage, indicating that an inversion channel with a p-type character was formed at a high-quality n-type diamond body/Al2O3 interface. The maximum drain current density and the field-effect mobility of a diamond MOSFET with a gate electrode length of 5 μm were 1.6 mA/mm and 8.0 cm2/Vs, respectively, at room temperature. © The Author(s) 2016

Suplatast tosilate alleviates nasal symptoms through the suppression of nuclear factor of activated T-cells-mediated IL-9 gene expression in toluene-2,4-diisocyanate-sensitized rats

Histamine H1 receptor (H1R) gene is upregulated in patients with pollinosis; its expression level is highly correlated with the nasal symptom severity. Antihistamines are widely used as allergy treatments because they inhibit histamine signaling by blocking H1R or suppressing H1R signaling as inverse agonists. However, long-term treatment with antihistamines does not completely resolve toluene-2,4-diisocyanate (TDI)-induced nasal symptoms, although it can decrease H1R gene expression to the basal level, suggesting additional signaling is responsible for the pathogenesis of the allergic symptoms. Here, we show that treatment with suplatast tosilate in combination with antihistamines markedly alleviates nasal symptoms in TDI-sensitized rats. Suplatast suppressed TDI-induced upregulation of IL-9 gene expression. Suplatast also suppressed ionomycin/phorbol-12-myristate-13-acetate-induced upregulation of IL-2 gene expression in Jurkat cells, in which calcineurin (CN)/nuclear factor of activated T-cells (NFAT) signaling is known to be involved. Immunoblot analysis demonstrated that suplatast inhibited binding of NFAT to DNA. Furthermore, suplatast suppressed ionomycin-induced IL-9 mRNA upregulation in RBL-2H3 cells, in which CN/NFAT signaling is also involved. These data suggest that suplatast suppressed NFAT-mediated IL-9 gene expression in TDI-sensitized rats and this might be the underlying mechanism of the therapeutic effects of combined therapy of suplatast with antihistamine

Catalytic monosilylation of 1,2-diols

The selective monosilylation of 1,2-diols catalyzed by dimethyltin dichloride was successfully developed. This procedure was applied to various 1,2-diols, giving monosilylated products in good to excellent yields with high chemoselectivity

An attenuated vaccinia vaccine encoding the severe acute respiratory syndrome coronavirus-2 spike protein elicits broad and durable immune responses, and protects cynomolgus macaques and human angiotensin-converting enzyme 2 transgenic mice from severe acute respiratory syndrome coronavirus-2 and its variants

As long as the coronavirus disease-2019 (COVID-19) pandemic continues, new variants of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) with altered antigenicity will emerge. The development of vaccines that elicit robust, broad, and durable protection against SARS-CoV-2 variants is urgently required. We have developed a vaccine consisting of the attenuated vaccinia virus Dairen-I (DIs) strain platform carrying the SARS-CoV-2 S gene (rDIs-S). rDIs-S induced neutralizing antibody and T-lymphocyte responses in cynomolgus macaques and human angiotensin-converting enzyme 2 (hACE2) transgenic mice, and the mouse model showed broad protection against SARS-CoV-2 isolates ranging from the early-pandemic strain (WK-521) to the recent Omicron BA.1 variant (TY38-873). Using a tandem mass tag (TMT)-based quantitative proteomic analysis of lung homogenates from hACE2 transgenic mice, we found that, among mice subjected to challenge infection with WK-521, vaccination with rDIs-S prevented protein expression related to the severe pathogenic effects of SARS-CoV-2 infection (tissue destruction, inflammation, coagulation, fibrosis, and angiogenesis) and restored protein expression related to immune responses (antigen presentation and cellular response to stress). Furthermore, long-term studies in mice showed that vaccination with rDIs-S maintains S protein-specific antibody titers for at least 6 months after a first vaccination. Thus, rDIs-S appears to provide broad and durable protective immunity against SARS-CoV-2, including current variants such as Omicron BA.1 and possibly future variants

初年次教育の深化に向けて ―ホスピタリティ概論の分析から―

本研究は、初年次教育の深化を図るために、その一つの科目である「ホスピタリティ概論」を対象として、受講生の感想等を分析し、授業の改善を図ることを目的としている。2017年度に開設された「ホスピタリティ概論」は、2年目を迎えるにあたって、前回の調査で明らかになった課題の幾つかに改善を加えて実践された1）。加えられた改善点は、上級生を学生スタッフとして雇用し、受講生の学修活動の促進を図ること、そして各課割り当てからボランティアの事務職員を担当にし、教職協働体制の円滑化を図ることの2点である。昨年度同様のクリッカー調査とアンケート調査を実施し、2年間の結果の比較・分析を行った。この結果、次のことが明らかになった。クリッカー調査　①平成30年度の方が29年度よりも、心身の不安を訴える1年生が多いこと。　②入学の動機づけとなるオープンキャンパスへの参加に関しては、平成30年度の方が、複数回参加や家族の参加が多くなっており、参加しなかった割合が低くなっていること。③全学オリエンテーションと学科別オリエンテーションの理解度に関しては、共に平成29年度の方が高い数値を示していること。アンケート調査　④「他学科の人とおしゃべりする機会が持てた」や、「他学科の人の意見を聞くことができて有意義だった」という授業内でのコミュニケーション関しては、平成30年度の方が高い評価が得られていること。⑤「ホスピタリティを理解する上で、この授業に合格点を与えることができる」に関しては、平成30年度の方が高い評価が得られていること。　⑥自由記述欄の文字数の調査では、平成30年度の方が高い数値になっていること。上述の①～③に示されているように、年度によって学生の質的な変化が生じているように見え、今後の動向を注視しなければならないことが明らかになった。また、④～⑥の結果からは、今年度の改善点である学生スタッフの活用によって、「ホスピタリティ概論」における学生の学修活動の活性化をもたらしたと判断する事ができる。しかし、他の項目では学科による差も見られ、課題が生じているといえる

チョウ シュウキ セキソウ コウゾウ ガタ マグネシウム ゴウキン ニ オケル キンク ヘンケイ キョドウ ノ カイメイ

熊本大

窒素ドーピング技術を用いた超低損失反転層ダイヤモンドMOSFETの開発

金沢大学ナノマテリアル研究所ダイヤモンド半導体は、優れた物性を有しているが、新しい半導体であるがゆえに、デバイス応用は進んでいない。本研究では、世界に先駆けて実現した反転層チャネルMOSFETにおいて低いチャネル移動度の原因である界面準位やキャリア散乱を理解するため、ダイヤモンド中の不純物濃度や表面ラフネスがデバイス特性に与える影響を調査した。結果、MOSFETにおいては窒素の低濃度化に課題を残すものの、従来の移動度を2倍程度改善する50 cm^2/Vsを実現した。また、ホウ素ドープp型ダイヤモンド表面のラフネスを低減させることで、MOSキャパシタにおいて10^11 cm^-2eV^-1台の低い界面準位密度を達成した。Diamond has excellent physical properties. However, the device applications have not progressed because many physics that cannot be understood remain. In this study, we investigated the effects of impurity concentration and surface roughness in diamond on device characteristics to understand the interface states and carrier scattering that cause low field-effect mobility in the inversion channel MOSFET, which was realized for the first time in the world. As a result, we have achieved 50 cm^2/Vs, which is about twice as good as the conventional mobility, although there is still an issue in reducing the nitrogen concentration in body of MOSFETs. In addition, by reducing the surface roughness of the boron-doped p-type diamond, a low interface state density of less than 10^12 cm^-2eV^-1 was achieved in the MOS capacitors.研究課題/領域番号:19K15042, 研究期間(年度):2019-04-01 - 2021-03-31出典：「窒素ドーピング技術を用いた超低損失反転層ダイヤモンドMOSFETの開発」研究成果報告書　課題番号19K15042（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/report/KAKENHI-PROJECT-19K15042/19K15042seika/）を加工して作