リンク集 RSS/ATOM 記事

タイトル: 能動的機械学習とハイスループット第一原理計算によるデータ駆動型非線形強誘電物性のひずみ最適化著者: 見波, 将; 丸山, 泰明; 阿部, 能将; 仲山, 智裕; 嶋田, 隆広抄録: Strain engineering is a crucial approach in the engineering field to optimize various physical properties of materials by applying mechanical strain loading. However, it is extremely challenging to find out the best conditions of strain with unprecedented physical properties in the vast strain space consisting of six components. Here, we developed a technical framework that enables efficient exploration of physical properties in the vast strain space based on machine learning (i.e., artificial neural networks), active learning, and high-throughput first-principles calculation. We demonstrated the active learning technique to successfully and efficiently construct an accurate machine learning model for ferroelectric PbTiO₃ with minimal first-prin ...

タイトル: Magnetosonic waves in the Martian ionosphere driven by upstream proton cyclotron waves: Two-point observations by MAVEN and Mars Express著者: Imada, K.; Harada, Y.; Fowler, C.M.; Collinson, G.; Halekas, J.S.; Ruhunusiri, S.; DiBraccio, G.A.; Romanelli, N.抄録: Recent observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) and Mars Express (MEX) spacecraft have suggested that pressure pulses originating from upstream proton cyclotron waves (PCWs) can “ring” the Martian magnetopause at the same frequency and drive magnetosonic waves in the upper ionosphere of Mars, thereby transporting energy from the solar wind into the ionosphere. However, the limitation of single-spacecraft measurements prevents simultaneous observations of the driver and response of this “ringing” process of the Martian magnetosphere. Here we utilize two-point measurements from MAVEN and MEX to characterize the ringing probability at which upstream PCWs drive compressional fluct ...

タイトル: Short-wave fadeout on mars: Radio absorption in the dayside martian ionosphere enhanced by solar flares著者: Harada, Y.; Sánchez-Cano, B.; Lester, M.; Ippolito, A.抄録: Solar flares can cause radio absorption in the D region of the Earth's ionosphere and consequently interrupt high-frequency radio communication systems, also known as short-wave fadeout or the Dellinger effect. We present an analogous radio absorption event observed at Mars during a solar flare. In this event, the Mars Express Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument fortuitously operated at low altitudes on the dayside around the terminator in a favorable configuration for surface echo measurements at the flare peak. The surface echo power during the flare is abnormally weak compared to nominal echo powers at corresponding solar zenith angles, suggesting flare-induced radio absorption in the dayside lower ionosphere of Mars. Additionally, long-term MARSIS data s ...

タイトル: Density of States and Binding Energy Informatics for Exploring Early Disease Detection in MOF-Metal Oxide Chemiresistive Sensors著者: Nurhuda, Maryam; Otake, Ken-ichi; Kitagawa, Susumu; Packwood, Daniel M.抄録: Human breath contains over 3000 volatile organic compounds, abnormal concentrations of which can indicate the presence of certain diseases. Recently, metal–organic framework (MOF)-metal oxide composite materials have been explored for chemiresistive sensor applications, however their ability to detect breath compounds associated with specific diseases remains unknown. In this work, a new high-throughput computational protocol for evaluating the sensing ability of MOF-metal oxide toward small organic compounds is presented. This protocol uses a cluster-based method for accelerated structure relaxation, and a combination of binding energies and density-of-states analysis to evaluate sensing ability, the latter measured using Wasserstein distances. This protocol ...

タイトル: Suspected Fatal Arrhythmic Events in Japanese Patients With Coronary Artery Disease -- From the CREDO-Kyoto PCI/CABG Registries Cohorts-2 and -3 --著者: Hanazawa, Koji; Shiomi, Hiroki; Morimoto, Takeshi; Ando, Kenji; Furukawa, Yutaka; Tada, Tomohisa; Tazaki, Junichi; Kadota, Kazushige; Tamura, Toshihiro; Sato, Yukihito; Matsuda, Mitsuo; Inoko, Moriaki; Shirotani, Manabu; Onodera, Tomoya; Shinoda, Eiji; Yamamoto, Takashi; Tamura, Takashi; Miki, Shinji; Aoyama, Takeshi; Suwa, Satoru; Minatoya, Kenji; Soga, Yoshiharu; Koyama, Tadaaki; Komiya, Tatsuhiko; Ohno, Nobuhisa; Ogawa, Tatsuya; Yamazaki, Fumio; Nishizawa, Junichiro; Esaki, Jiro; Kanemitsu, Naoki; Nakagawa, Yoshihisa; Kimura, Takeshi抄録: BACKGROUND: Fatal arrhythmic events (FAEs), such as sudden cardiac death (SCD) and fatal ventricular arrhythmias, are a devastating complication in patients with coronary artery disease (CAD). Therefore, in this study we aimed to assess the incidence of FAEs in more recent Japanes ...

タイトル: Coronary Artery Calcification on Chest Computed Tomography as a Predictor of Cardiovascular Adverse Events in Patients With COVID-19 -- A Multicenter Retrospective Study in Japan --著者: Watase, Mayuko; Shiraishi, Yusuke; Chubachi, Shotaro; Tanabe, Naoya; Maetani, Tomoki; Asakura, Takanori; Namkoong, Ho; Tanaka, Hiromu; Shimada, Takashi; Azekawa, Shuhei; Otake, Shiro; Fukushima, Takahiro; Nakagawara, Kensuke; Masaki, Katsunori; Terai, Hideki; Mochimaru, Takao; Sasaki, Mamoru; Ueda, Soichiro; Kato, Yukari; Harada, Norihiro; Suzuki, Shoji; Yoshida, Shuichi; Tateno, Hiroki; Yamada, Yoshitake; Jinzaki, Masahiro; Okada, Yukinori; Koike, Ryuji; Ishii, Makoto; Kimura, Akinori; Imoto, Seiya; Miyano, Satoru; Ogawa, Seishi; Kanai, Takanori; Fukunaga, Koichi抄録: BACKGROUND: Coronary artery calcification (CAC) detected through chest computed tomography (CT) strongly predicts cardiovascular events in asymptomatic individuals undergoing primary prevention. Few studies with limited ...

タイトル: Determination of patient-specific trajectory for biaxially rotational dynamic-radiation therapy using a new O-ring-shaped image guided radiotherapy system著者: Hirashima, Hideaki; Adachi, Hiroki; Ono, Tomohiro; Nakamura, Mitsuhiro; Ono, Yuka; Iwai, Takahiro; Yoshimura, Michio; Mizowaki, Takashi抄録: Background and purpose: This study developed a trajectory search method for biaxially rotational dynamicradiation therapy (BROAD-RT) using a new O-ring-shaped linac, aimed at identifying a patient-specific trajectory in a commercial treatment planning system. Subsequently, its efficacy in the treatment of pancreatic cancer was assessed. Materials and methods: BROAD-RT is a beam delivery technique in which the gantry and O-ring are simultaneously rotated around two axes. A beam’s eye view-based structure map was generated, and the Dijkstra algorithm was then applied to explore the BROAD-RT for minimizing radiation doses to critical organs in RayStation. This procedure was ...

タイトル: Age-disproportionate atrophy in Alzheimer's disease and Parkinson's disease spectra著者: Yoshinaga, Kenji; Matsushima, Toma; Abe, Mitsunari; Takamura, Tsunehiko; Togo, Hiroki; Wakasugi, Noritaka; Sawamoto, Nobukatsu; Murai, Toshiya; Mizuno, Toshiki; Matsuoka, Teruyuki; Kanai, Kazuaki; Hoshino, Hiroshi; Sekiguchi, Atsushi; Fuse, Nobuo; Mugikura, Shunji; Hanakawa, Takashi抄録: INTRODUCTION: Brain age gap (BAG), defined as the difference between MRI-predicted ‘brain age’ and chronological age, can capture information underlying various neurological disorders. We investigated the pathophysiological significance of the BAG across neurodegenerative disorders. METHODS: We developed a brain age estimator using structural MRIs of healthy-aged individuals from one cohort study. Subsequently, we applied this estimator to people with Alzheimer's disease spectra (AD) and Parkinson's disease (PD) from another cohort study. We investigated brain sources responsible for BAGs amon ...

タイトル: Inhomogeneous Electrostatic Potentials on the Dayside Lunar Surface in the Terrestrial Magnetotail Lobes: The Role of Lunar Crustal Magnetic Fields著者: Kato, Masahisa; Harada, Yuki; Saito, Yoshifumi; Yokota, Shoichiro; Nishino, N. Masaki; Takahashi, Futoshi; Shimizu, Hisayoshi; Xu, Shaosui; Poppe, R. Andrew; Halekas, S. Jasper抄録: Though the Moon does not possess a global magnetic field like the Earth, there are localized crustal magnetic fields on the lunar surface. Because of the plasma interaction with the crustal magnetic fields, electrostatic and electromagnetic environments near magnetized regions can differ from those near non-magnetized regions on the Moon. Previous studies observationally revealed the difference in the electrostatic potential on the lunar surface between magnetized and non-magnetized regions of the Moon in the solar wind, which was attributed to upward electric fields formed by electron-ion decoupling above the magnetic anomaly regions. How ...

タイトル: Catalytic mechanism underlying the regiospecificity of coumarin-substrate transmembrane prenyltransferases in Apiaceae著者: Han, Junwen; Munakata, Ryosuke; Takahashi, Hironobu; Koeduka, Takao; Kubota, Mayumi; Moriyoshi, Eiko; Hehn, Alain; Sugiyama, Akifumi; Yazaki, Kazufumi抄録: Plant membrane-bound prenyltransferases (PTs) catalyze the transfer of prenyl groups to acceptor substrates, phenols, using prenyl diphosphates as the donor substrate. The presence of prenyl residues in the reaction products, prenylated phenols, is key to the expression of a variety of physiological activities. Plant PTs generally exhibit high specificities for both substrate recognition and prenylation sites, while the molecular mechanism involved in these enzymatic properties is largely unknown. In this study, we performed a systematic biochemical analysis to elucidate the catalytic mechanism responsible for the reaction specificity of plant PTs. Using two representative PTs, PsPT₁ and PsP ...