Molecular Dynamics Observation of Iron-Carbon Precursors of Carbon Nanotube and Development of Iron-Carbon Potential

We have focused on the growth process of metal and carbon mixed clusters that are precursors for carbon nanotubes. The molecular dynamics method using the Brenner potential was employed for modeling carbon-carbon interactions as well as carbon-iron interactions. As for carbon-iron interactions, the parameters were derived using DFT calculation. The Finnis-Sinclair potential was employed for irons. In order to observe the deposition process of carbon atoms, we adjusted the potential parameters to reproduce the bulk melting points of graphite, iron, and cementite, which was a model material of iron-carbon composite. We observed the initial growth process by preparing iron-carbon mixed clusters (approximately 200 iron atoms and 70 carbon atoms) as precursor clusters. Additional carbon atoms were then gradually supplied to this mixture at 1000 K and 1200 K. Consequently, the graphite structure was formed on the mixture surface, but at some phases, the cap structure was observed at 1200 K

Oral Tacrolimus in Patients with Ulcerative Colitis

Tacrolimus is a macrolide immunosuppressant that is structurally similar to rapamycin and has been found to have potent immunosuppressive properties, showing 10- to 100-fold higher potency for inhibiting lymphocyte activation than cyclosporine A (CsA). Because less variability in absorption and serum levels is observed among patients treated with tacrolimus compared with those who receive oral CsA, tacrolimus has been suggested to be more easily and safely administered to patients with refractory ulcerative colitis (UC) than CsA. However, because oral tacrolimus has a slower onset of action than intravenous CsA and food intake is known to reduce tacrolimus serum trough levels due to its low absorption rate, the proper method for administration of oral tacrolimus has not been determined. Moreover, the long-term effects of oral tacrolimus also remain unclear. In this chapter, key issues regarding the use of oral tacrolimus in patients with UC are reviewed

Origin of the "Disk-Line" Feature in the X-Ray Energy Spectrum of a Seyfert Galaxy, NGC4151

We have studied the origin of the broad and skewed feature at 4.5-7.5 keV in the energy spectra of NGC4151 using the ASCA and RXTE data. The feature consists of a narrow peak at 6.4 keV and a broad wing extended between 4.5-7.5 keV. An analysis of the long-term variations revealed that the feature became variable only on a time scale longer than 1.5x10^6 s. Through a comparison with the continuum variabilities, we found that the emission region of the excess flux at 4.5-7.5 keV has an extent of 10^17 cm. The broad and skewed feature at 4.5-7.5 keV may be explained by the so-called ``disk-line'' model. If so, the size of the line-emitting region, 10^17 cm, should be equal to several or ten-times the Schwarzschild radius of the central black hole. This results in a black hole mass of 10^11 solar mass, which may be too large for NGC4151. We propose an alternative explanation for the broad and skewed feature, i.e. a ``reflection'' model, which can also reproduce the overall energy spectra very well. In this model, cold matter with a sufficiently large column density is irradiated by X-rays to produce a reflected continuum, which constitutes the broad wing of the feature, and narrow fluorescent lines. The equivalent width of the iron fluorescent line (~2 keV) and the upper limit of its width (sigma < 92 eV) are also consistent with this model. From these results and considerations, we conclude that the ``disk-line'' model has difficulty to explain the spectral variations of NGC4151, and the reflection model is more plausible.Comment: 19 pages, 16 figures, PASJ accepte

First Language Influence on Adverbial Clauses of Reason: Focusing on Japanese English Learners’ Use of Because-Clauses

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Regulation of Osteoclastogenesis and Bone Resorption by miRNAs

Osteoclasts are specialized bone-resorbing cells that contribute to physiological bone development and remodeling in bone metabolism throughout life. Abnormal production and activation of osteoclasts lead to excessive bone resorption in pathological conditions, such as in osteoporosis and in arthritic diseases with bone destruction. Recent epigenetic studies have shed novel insight into the dogma of the regulation of gene expression. microRNAs belong to a category of epigenetic regulators, which post-transcriptionally regulate and silence target gene expression, and thereby control a variety of biological events. In this review, we discuss miRNA biogenesis, the mechanisms utilized by miRNAs, several miRNAs that play important roles in osteoclast differentiation, function, survival and osteoblast-to-osteoclast communication, and their translational potential and challenges in bone biology and skeletal diseases

O-Alkylation of Dihydroxo(tetraarylporphyrinato)phosphorus(V) and Antimony(V) Complexes with Alkyl Halides

The O-alkylation of dihydroxo(tetraarylporphyrinato)phosphorus(V) complexes with several kinds of alkyl bromide in MeCN in the presence of K2CO3 and 18-crown-6 ether produced dialkoxo(tetraarylporphyrinato)phosphorus(V) complexes in-moderate-good yields. Similar O-alkylation was applied to dihydroxo(tetraarylporphyrinato)antimony(V) complexes. The O-alkylation proceeded by the occurrence of an SN2 attack of the alkoxide anion of the complexes at the carbon substituted with halides

Comparing Code Similarity Using Information Retrieval Techniques and Deep Learning

コード片の類似性判定法はソフトウェア工学における重要な基礎技術であり，コードクローン検出やコード片検索などで使用される．コード片の類似性判定法では，構文的な類似性だけでなく，処理内容の意味的な類似性も判定することが重要である．我々の先行研究では，情報検索技術に基づくベクトル表現とコサイン類似度を組み合わせた類似性判定法を用いていた．この手法は処理内容の意味的な類似性を高速に判定できる一方で，検出漏れが多い課題がある．また近年，深層学習を用いた類似性判定法が提案されている．この手法は意味的な類似性を高い精度で判定できる反面，実行速度が遅い課題がある．そこで本研究では，判定精度と実行速度の二つの観点で情報検索技術に基づくベクトル表現と深層学習の効果的な組み合わせを調査する．調査の結果，情報検索技術の一種であるLSI (Latent Semantic Indexing)と深層学習モデルの組み合わせが判定精度の面で最も高い値となった．またこの組み合わせは実行速度が最も速いことも確認した．横井, 一輝, 崔, 恩瀞, 吉田, 則裕, et al. 情報検索技術と深層学習を用いたコード片類似性判定法の比較調査. 電子情報通信学会論文誌D 情報・システム J106-D, 231 (2023); https://doi.org/10.14923/transinfj.2022pdp0009

Aging of hospital physicians in rural Japan: A longitudinal study based on national census data

Background The disparity in the number of urban and rural physicians is a social problem in Japan. There may also be a disparity in the age of physicians. This study longitudinally examines both geographic and age distributions of physicians. Methods Individual data from the Survey of Physicians, Dentists and Pharmacists in 1994, 2004 and 2014 and municipality data from the National Population Census were used. The 2015 municipality border was applied to all years, and all municipalities were classified into equalsize quintiles based on population density. Both municipalities and physicians were longitudinally observed. Results Between 1994 and 2014, the number of physicians per 100,000 population increased by 31.8% in the most urban group of municipalities and 17.4% in the most rural group. The average age of physicians was highest in the most rural and lowest in the most urban group. The difference in average age between the urban and rural physicians widened from 2.1 years in 1994 to 6.0 years in 2014. This disparity is particularly pronounced among hospital physicians (from 1.5 years in 1994 to 7.6 years in 2014). In the most rural group, the number of hospital physicians younger than 40 years old has decreased by 59.4%, while the number of those 55±70 has grown by 153% and the number older than 70 years old by 41.0%. Between 1994 and 2004, only 23.0% of hospital physicians younger than 40 years old were retained in the most rural group; the retention rate fell to 19.3% between 2004 and 2014, while the rates increased in older physicians. Conclusions The uneven distribution of physicians is increasing in Japan, as is the aging of rural hospital physicians. Shortage of physicians in rural areas may be more serious than that shown as their headcount.This research was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number 16K09145 (http://www.jsps.go.jp/english/e-grants/index.html) (KI)