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1,067 results on '"Yamamoto, Yuta"'

2. New technique to select recent fast-quenching galaxies at $z\sim2$ using the optical colors

Author

Kubo, Mariko, Nagao, Tohru, Uchiyama, Hisakazu, Yamashita, Takuji, Toba, Yoshiki, Kajisawa, Masaru, and Yamamoto, Yuta

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Many massive quiescent galaxies have been discovered at $z>2$ thanks to multi-wavelength deep and wide surveys, however, substantial deep near-infrared spectroscopic observations are needed to constrain their star-formation histories statistically. Here, we present a new technique to select quiescent galaxies with a short quenching timescale ($\leq0.1$ Gyr) at $z\sim2$ photometrically. We focus on a spectral break at $\sim1600$ \AA~that appears for such fast-quenching galaxies $\sim1$ Gyr after quenching when early A-type stars go out, but late A-type stars still live. This spectral break at $z\sim2$ is similar to a Lyman break at $z\sim4$. We construct a set of color criteria for $z\sim2$ fast-quenching galaxies on $g-r$ vs. $r-i$ and $i-J$ vs. $J-H$ or $\rm i-[3.6]$ vs. $\rm [3.6]-[4.5]$ color diagrams, which are available with the existing and/or future wide imaging surveys, by simulating various model galaxy spectra and test their robustnesses using the COSMOS2020 catalog. Galaxies with photometric and/or spectroscopic redshifts $z\sim2$ and low specific star formation rates are successfully selected using these colors. The number density of these fast-quenching galaxy candidates at $z\sim2$ suggests that massive galaxies not so far above the star-formation main sequence at $z=3-4$ should be their progenitors., Comment: 12 pages, 11 figures, accepted for publication in MNRAS

Published
2023

3. Investigating Quantitative-Qualitative Topical Preference: A Comparative Study of Early and Late Engagers in Japanese ChatGPT Conversations

Author

Fukuma, Tomoki, Noda, Koki, Yamamoto, Yuta, Hoshi, Takaya, Ichikawa, Yoshiharu, Kambe, Kyosuke, Masubuchi, Yu, and Toriumi, Fujio

Subjects
Computer Science - Social and Information Networks
Abstract

This study investigates engagement patterns related to OpenAI's ChatGPT on Japanese Twitter, focusing on two distinct user groups - early and late engagers, inspired by the Innovation Theory. Early engagers are defined as individuals who initiated conversations about ChatGPT during its early stages, whereas late engagers are those who began participating at a later date. To examine the nature of the conversations, we employ a dual methodology, encompassing both quantitative and qualitative analyses. The quantitative analysis reveals that early engagers often engage with more forward-looking and speculative topics, emphasizing the technological advancements and potential transformative impact of ChatGPT. Conversely, the late engagers intereact more with contemporary topics, focusing on the optimization of existing AI capabilities and considering their inherent limitations. Through our qualitative analysis, we propose a method to measure the proportion of shared or unique viewpoints within topics across both groups. We found that early engagers generally concentrate on a more limited range of perspectives, whereas late engagers exhibit a wider range of viewpoints. Interestingly, a weak correlation was found between the volume of tweets and the diversity of discussed topics in both groups. These findings underscore the importance of identifying semantic bias, rather than relying solely on the volume of tweets, for understanding differences in communication styles between groups within a given topic. Moreover, our versatile dual methodology holds potential for broader applications, such as studying engagement patterns within different user groups, or in contexts beyond ChatGPT.

Published
2023

4. Bicategorical Models of Classical Propositional Logic

Author

Yamamoto, Yuta

Subjects
Mathematics - Category Theory
Abstract

F\"uhrmann and Pym constructed models of classical propositional logic in an order-enriched categorical setting, whose typical example is the category $\mathbf{Rel}$ of sets and relations. It is remarkable in that they are both non-degenerate and symmetric, i.e., free from the choices of the reduction strategy. As a furter categorification of this direction, we give bicategorical models of classical propositional logic that is also symmetric and non-degenerate. Primal examples of our models include $\mathbf{Rel}$, $\mathbf{Span}$, and $\mathbf{Prof}$, which shows that we can construct models that are non-degenerate not only for $1$-cells but also for $2$-cells and the logical negations., Comment: 10 pages

Published
2023

15. Disrupted CaV1.2 selectivity causes overlapping long QT and Brugada syndrome phenotypes in the CACNA1C-E1115K iPS cell model

Author

Kashiwa, Asami, Makiyama, Takeru, Kohjitani, Hirohiko, Maurissen, Thomas L., Ishikawa, Taisuke, Yamamoto, Yuta, Wuriyanghai, Yimin, Gao, Jingshan, Huang, Hai, Imamura, Tomohiko, Aizawa, Takanori, Nishikawa, Misato, Chonabayashi, Kazuhisa, Mishima, Hiroyuki, Ohno, Seiko, Toyoda, Futoshi, Sato, Seiichi, Yoshiura, Koh-Ichiro, Takahashi, Kazuhiro, Yoshida, Yoshinori, Woltjen, Knut, Horie, Minoru, Makita, Naomasa, and Kimura, Takeshi

Published
2023
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16. Phenotype-Based High-Throughput Classification of Long QT Syndrome Subtypes Using Human Induced Pluripotent Stem Cells

Author

Yoshinaga, Daisuke, Baba, Shiro, Makiyama, Takeru, Shibata, Hirofumi, Hirata, Takuya, Akagi, Kentaro, Matsuda, Koichi, Kohjitani, Hirohiko, Wuriyanghai, Yimin, Umeda, Katsutsugu, Yamamoto, Yuta, Conklin, Bruce R, Horie, Minoru, Takita, Junko, and Heike, Toshio

Subjects
Biological Sciences, Genetics, Human Genome, Orphan Drug, Stem Cell Research - Induced Pluripotent Stem Cell - Human, Rare Diseases, Stem Cell Research - Induced Pluripotent Stem Cell, Cardiovascular, Heart Disease, Clinical Research, Stem Cell Research, Aetiology, 2.1 Biological and endogenous factors, Action Potentials, Adolescent, Adult, Case-Control Studies, Cell Differentiation, Child, Female, High-Throughput Screening Assays, Humans, Induced Pluripotent Stem Cells, Long QT Syndrome, Male, Middle Aged, Myocytes, Cardiac, Patch-Clamp Techniques, Phenotype, Potassium Channel Blockers, Sodium Channel Blockers, Tetrodotoxin, Young Adult, genome editing, induced pluripotent stem cell, long QT syndrome, multi-electrode array, phenotype-based diagnosis, Biochemistry and Cell Biology, Clinical Sciences, Biochemistry and cell biology
Abstract

For long QT syndrome (LQTS), recent progress in genome-sequencing technologies enabled the identification of rare genomic variants with diagnostic, prognostic, and therapeutic implications. However, pathogenic stratification of the identified variants remains challenging, especially in variants of uncertain significance. This study aimed to propose a phenotypic cell-based diagnostic assay for identifying LQTS to recognize pathogenic variants in a high-throughput manner suitable for screening. We investigated the response of LQT2-induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iPSC-CMs) following IKr blockade using a multi-electrode array, finding that the response to IKr blockade was significantly smaller than in Control-iPSC-CMs. Furthermore, we found that LQT1-iPSC-CMs and LQT3-iPSC-CMs could be distinguished from Control-iPSC-CMs by IKs blockade and INa blockade, respectively. This strategy might be helpful in compensating for the shortcomings of genetic testing of LQTS patients.

Published
2019

18. Novel Calmodulin Variant p.E46K Associated With Severe Catecholaminergic Polymorphic Ventricular Tachycardia Produces Robust Arrhythmogenicity in Human Induced Pluripotent Stem Cell–Derived Cardiomyocytes

Author

Gao, Jingshan, Makiyama, Takeru, Yamamoto, Yuta, Kobayashi, Takuya, Aoki, Hisaaki, Maurissen, Thomas L., Wuriyanghai, Yimin, Kashiwa, Asami, Imamura, Tomohiko, Aizawa, Takanori, Huang, Hai, Kohjitani, Hirohiko, Nishikawa, Misato, Chonabayashi, Kazuhisa, Fukuyama, Megumi, Manabe, Hiromi, Nakau, Kouichi, Wada, Tsutomu, Kato, Koichi, Toyoda, Futoshi, Yoshida, Yoshinori, Makita, Naomasa, Woltjen, Knut, Ohno, Seiko, Kurebayashi, Nagomi, Murayama, Takashi, Sakurai, Takashi, Horie, Minoru, and Kimura, Takeshi

Published
2023
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19. Evolution of the Cdk4/6–Cdkn2 system in invertebrates.

Author

Yuki, Shiori, Sasaki, Shunsuke, Yamamoto, Yuta, Murakami, Fumika, Sakata, Kazumi, and Araki, Isato

Subjects
CELL cycle regulation, CYCLIN-dependent kinase inhibitors, COMPARATIVE genomics, CELL cycle, KINASE inhibitors
Abstract

The cell cycle is driven by cyclin‐dependent kinases (Cdks). The decision whether the cell cycle proceeds is made during G1 phase, when Cdk4/6 functions. Cyclin‐dependent kinase inhibitor 2 (Cdkn2) is a specific inhibitor of Cdk4/6, and their interaction depends on D84 in Cdkn2 and R24/31 in Cdk4/6. This knowledge is based mainly on studies in mammalian cells. Here, we comprehensively analyzed Cdk4/6 and Cdkn2 in invertebrates and found that Cdk4/6 was present in most of the investigated phyla, but the distribution of Cdkn2 was rather uneven among and within the phyla. The positive charge of R24/R31 in Cdk4/6 was conserved in all analyzed species in phyla with Cdkn2. The presence of Cdkn2 and the conservation of the positive charge were statistically correlated. We also found that Cdkn2 has been tightly linked to Fas associated factor 1 (Faf1) during evolution. We discuss potential interactions between Cdkn2 and Cdk4/6 in evolution and the possible cause of the strong conservation of the microsynteny. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Targeting Oxidative Phosphorylation with a Novel Thiophene Carboxamide Increases the Efficacy of Imatinib against Leukemic Stem Cells in Chronic Myeloid Leukemia.

Author

Kusaba, Kana, Watanabe, Tatsuro, Kidoguchi, Keisuke, Yamamoto, Yuta, Tomoda, Ayaka, Hoshiko, Toshimi, Kojima, Naoto, Nakata, Susumu, and Kimura, Shinya

Subjects
CHRONIC myeloid leukemia, PROTEIN-tyrosine kinase inhibitors, PROTEIN-tyrosine kinases, OXIDATIVE phosphorylation, COLON cancer
Abstract

Patients with chronic myeloid leukemia (CML) respond to tyrosine kinase inhibitors (TKIs); however, CML leukemic stem cells (LSCs) exhibit BCR::ABL kinase-independent growth and are insensitive to TKIs, leading to disease relapse. To prevent this, new therapies targeting CML-LSCs are needed. Rates of mitochondria-mediated oxidative phosphorylation (OXPHOS) in CD34+CML cells within the primitive CML cell population are higher than those in normal undifferentiated hematopoietic cells; therefore, the inhibition of OXPHOS in CML-LSCs may be a potential cure for CML. NK-128 (C33H61NO5S) is a structurally simplified analog of JCI-20679, the design of which was based on annonaceous acetogenins. NK-128 exhibits antitumor activity against glioblastoma and human colon cancer cells by inhibiting OXPHOS and activating AMP-activated protein kinase (AMPK). Here, we demonstrate that NK-128 effectively suppresses the growth of CML cell lines and that the combination of imatinib and NK-128 is more potent than either alone in a CML xenograft mouse model. We also found that NK-128 inhibits colony formation by CD34+ CML cells isolated from the bone marrow of untreated CML patients. Taken together, these findings suggest that targeting OXPHOS is a beneficial approach to eliminating CML-LSCs, and may improve the treatment of CML. [ABSTRACT FROM AUTHOR]

Published
2024
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21. Pt single atom alloyed sub-1 nm thick Fe overlayer on supported Cu nanoparticles for methylcyclohexane dehydrogenation.

Author

Oda, Akira, Ichihashi, Kosei, Yamamoto, Yuta, Ohtsu, Takeshi, Shi, Wei, Sawabe, Kyoichi, and Satsuma, Atsushi

Abstract

There is an urgent need for the development of a precious metal-conserving catalyst having high activity, selectivity, and durability for methylcyclohexane (MCH) dehydrogenation, a significant aspect of hydrogen storage and transportation. A Pt-single atom alloyed Fe catalyst with sub-1 nm size is a good candidate for this purpose because of meeting site requirements for enhancement of activity, durability, selectivity, and utilization efficiency of Pt. However, this design is challenging due to the high surface energy of Fe. In this study, to break the limitation of catalyst design, we used a combination of two phenomena spontaneously taking place at the solid surface, i.e., (1) Fe dispersion on Cu, and (2) substitution of metallic Fe atoms with Pt cations. Here, we report a Pt single-atom alloyed sub-1 nm thick Fe overlayer on Cu nanoparticles. The Fe overlayer serves as the host metal to restrict Pt single atoms at the surface and provides an optimal coordination environment for MCH dehydrogenation. Furthermore, the sub-1 nm thick Fe overlayer features low crystallinity and superior decoking properties, which imparts product/coke poisoning resistance to the Pt single atom site, resulting in enhancements of both durability and activity. The H2-evolution rate per Pt mass was at least 133 times higher than that of state-of-the-art catalysts: Pt-based intermetallic compounds. This research demonstrates the significance of a single-atom-alloying approach with unique nanostructures specifically formed at the solid surface for the development of more efficient sustainable catalytic transformation processes. [ABSTRACT FROM AUTHOR]

Published
2024
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26. Crystallization of Strictly Linear Poly(ethylene-ran-acrylic acid) Copolymer: Impacts of Pendant Group Insertion and Hydrogen Bonding

Author

Zhou, Jian, Takahashi, Kohei, Nozaki, Kyoko, Yamamoto, Yuta, Katashima, Takuya, Yoshie, Naoko, and Nakagawa, Shintaro

Abstract

Functionalized polyolefins hold great promise as a material group for a future society. The hierarchical structure formation process during crystallization and melting of such polymers is greatly influenced by the inter- and intrachain interactions induced by functional groups. Herein, we report the comprehensive structural analysis of strictly linear poly(ethylene-ran-acrylic acid), i.e., polyethylene bearing pendant carboxyl (−COOH) groups randomly along the chain (PE-COOH), during the crystallization and melting processes. Additional use of the corresponding methyl ester (PE-COOMe) and polyethylene (PE) enabled us to separate the effects of hydrogen bonds (H-bonds) among the −COOH groups from those caused by the random insertion of pendant groups. The crystallizable methylene sequences were divided by the randomly inserted pendant groups, giving rise to the sequence-length selective crystallization. That is, longer sequences crystallized at higher temperatures and vice versa. This significantly hindered the crystallization rate, crystal thickness, and crystallinity and led to a strong melt memory effect. The H-bonding between −COOH groups acted as physical cross-linking for the PE chains and hindered the chain motion. This further slowed the crystallization and reinforced the melt memory effect. On the other hand, the H-bonds contributed to increased crystallinity and melting point of PE-COOH crystallized at high temperatures, compared to those of PE-COOMe. Thus, it was found that the H-bonding of −COOH groups stabilized the crystals formed at high temperatures. This work presents a unified view of the crystallization and melting behavior of strictly linear PE with interacting pendant groups, providing the possibility to precisely control the crystalline morphology in scales of both lamella and spherulite by altering the thermal history.

Published
2024
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31. Short‐term outcomes of laparoscopic and robotic distal gastrectomy for gastric cancer: Real‐world evidence from a large‐scale inpatient database in Japan

Author

Hondo, Nao, primary, Yamamoto, Yuta, additional, Nakabe, Takayo, additional, Otsubo, Tetsuya, additional, Kitazawa, Masato, additional, Nakamura, Satoshi, additional, Koyama, Makoto, additional, Miyazaki, Satoru, additional, Kataoka, Masahiro, additional, and Soejima, Yuji, additional

Published
2024
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38. Quantum de-trapping and transport of heavy defects in tungsten

Author

Arakawa, Kazuto, Marinica, Mihai-Cosmin, Fitzgerald, Steven, Proville, Laurent, Nguyen-Manh, Duc, Dudarev, Sergei L., Ma, Pui-Wai, Swinburne, Thomas D., Goryaeva, Alexandra M., Yamada, Tetsuya, Amino, Takafumi, Arai, Shigeo, Yamamoto, Yuta, Higuchi, Kimitaka, Tanaka, Nobuo, Yasuda, Hidehiro, Yasuda, Tetsuya, and Mori, Hirotaro

Published
2020
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44. Leuconostoc mesenteroides subsp. strain NTM048 ameliorated nasal symptoms in patients with Japan cedar pollinosis: Randomized, double-blind, and placebo-controlled trial

Author

Yamamoto, Yuta, primary, Sugita, Gen, additional, Hiraoka, Masanobu, additional, Takagi, Saori, additional, Yamagishi, Naoko, additional, Kawashima, Shuji, additional, Tanioka, Kensuke, additional, Nishi, Toshio, additional, Yamamoto, Sachi, additional, Kakutani, Chiemi, additional, Yanase, Agi, additional, Kanai, Yoshimitsu, additional, Kato, Seiya, additional, and Hotomi, Muneki, additional

Published
2023
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46. Rhomboid protease RHBDL4/RHBDD1 cleaves SREBP-1c at endoplasmic reticulum monitoring and regulating fatty acids

Author

Han, Song-Iee, primary, Nakakuki, Masanori, additional, Nakagawa, Yoshimi, additional, Wang, Yunong, additional, Araki, Masaya, additional, Yamamoto, Yuta, additional, Tokiwa, Hiroaki, additional, Takeda, Hiroyuki, additional, Mizunoe, Yuhei, additional, Motomura, Kaori, additional, Ohno, Hiroshi, additional, Kainoh, Kenta, additional, Murayama, Yuki, additional, Aita, Yuichi, additional, Takeuchi, Yoshinori, additional, Osaki, Yoshinori, additional, Miyamoto, Takafumi, additional, Sekiya, Motohiro, additional, Matsuzaka, Takashi, additional, Yahagi, Naoya, additional, Sone, Hirohito, additional, Daitoku, Hiroaki, additional, Sato, Ryuichiro, additional, Kawano, Hiroyuki, additional, and Shimano, Hitoshi, additional

Published
2023
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47. A Combination of Alectinib and DNA-Demethylating Agents Synergistically Inhibits Anaplastic-Lymphoma-Kinase-Positive Anaplastic Large-Cell Lymphoma Cell Proliferation

Author

Kawasoe, Kazunori, primary, Watanabe, Tatsuro, additional, Yoshida-Sakai, Nao, additional, Yamamoto, Yuta, additional, Kurahashi, Yuki, additional, Kidoguchi, Keisuke, additional, Ureshino, Hiroshi, additional, Kamachi, Kazuharu, additional, Fukuda-Kurahashi, Yuki, additional, and Kimura, Shinya, additional

Published
2023
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