研究者詳細 - 青野　真士

青野　真士 (アオノ　マサシ)

Aono, Masashi

写真a

所属（所属キャンパス）: 理工学研究科（矢上）

職名: 特任教授（有期）

HP

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自然計算
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Estimating the capacity for production of formamide by radioactive minerals on the prebiotic Earth

Adam Zachary R., Hongo Yayoi, Cleaves H. James, Yi Ruiqin, Fahrenbach Albert C., Yoda Isao, Aono Masashi

Scientific Reports 8 （ 1 ） 2018年12月

ISSN 2045-2322

　概要を見る

Water creates special problems for prebiotic chemistry, as it is thermodynamically favorable for amide and phosphodiester bonds to hydrolyze. The availability of alternative solvents with more favorable properties for the formation of prebiotic molecules on the early Earth may have helped bypass this so-called "water paradox". Formamide (FA) is one such solvent, and can serve as a nucleobase precursor, but it is difficult to envision how FA could have been generated in large quantities or accumulated in terrestrial surface environments. We report here the conversion of aqueous acetonitrile (ACN) via hydrogen cyanide (HCN) as an intermediate into FA by γ-irradiation under conditions mimicking exposure to radioactive minerals. We estimate that a radioactive placer deposit could produce 0.1-0.8 mol FA km^-2 year^-1. A uraninite fission zone comparable to the Oklo reactors in Gabon can produce 0.1-1 mol m^-2 year^-1, orders of magnitude greater than other scenarios of FA production or delivery for which reaching sizeable concentrations of FA are problematic. Radioactive mineral deposits may be favorable settings for prebiotic compound formation through emergent geologic processes and FA-mediated organic chemistry.
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Amoeba-inspired electronic solution-searching system and its application to finding walking maneuver of a multi-legged robot

Saito Kenta, Suefuji Naoki, Kasai Seiya, Aono Masashi

2018-May 127 - 131 2018年07月

　概要を見る

We have developed a bio-inspired electronic computing system, the 'electronic amoeba'. This system was designed to search for a solution to a combinational optimization problem, as inspired by foraging behavior of a single-celled amoeboid organism that is trying to maximize its food intake while satisfying given constraints. We electronically implement the system and demonstrate its solution search capability for solving the Boolean satisfiability problem, SAT. We apply the electronic amoeba to autonomous walking control of a multi-legged robot. Each leg joint has three-valued state and the electronic amoeba successively searches for a combination of the leg joint states to satisfy the objective of moving straight depending on the state of the robot.
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Category Theoretic Analysis of Photon-Based Decision Making

Naruse Makoto, Kim Song Ju, Aono Masashi, Berthel Martin, Drezet Aurélien, Huant Serge, Hori Hirokazu

International Journal of Information Technology and Decision Making 1 - 29 2018年05月

ISSN 0219-6220

　概要を見る

Decision making is a vital function in the age of machine learning and artificial intelligence; however, its physical realization and theoretical fundamentals are not yet well understood. In our former study, we demonstrated that single photons can be used to make decisions in uncertain, dynamically changing environments. The two-armed bandit problem was successfully solved using the dual probabilistic and particle attributes of single photons. In this study, we present a category theoretic modeling and analysis of single-photon-based decision making, including a quantitative analysis that agrees well with the experimental results. The category theoretic model unveils complex interdependencies of the entities of the subject matter in the most simplified manner, including a dynamically changing environment. In particular, the octahedral structure and the braid structure in triangulated categories provide better understandings and quantitative metrics of the underlying mechanisms for the single-photon decision maker. This study provides insight and a foundation for analyzing more complex and uncertain problems for machine learning and artificial intelligence.
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Size-dependent affinity of glycine and its short oligomers to pyrite surface

Afrin Rehana, Ganbaatar Narangerel, Aono Masashi, Cleaves H. James, Yano Taka Aki, Hara Masahiko

International Journal of Molecular Sciences 19 （ 2 ） 2018年02月

ISSN 1661-6596

　概要を見る

The interaction strength of progressively longer oligomers of glycine, (Gly), di-Gly, tri-Gly, and penta-Gly, with a natural pyrite surface was directly measured using the force mode of an atomic force microscope (AFM). In recent years, selective activation of abiotically formed amino acids on mineral surfaces, especially that of pyrite, has been proposed as an important step in many origins of life scenarios. To investigate such notions, we used AFM-based force measurements to probe possible non-covalent interactions between pyrite and amino acids, starting from the simplest amino acid, Gly. Although Gly itself interacted with the pyrite surface only weakly, progressively larger unbinding forces and binding frequencies were obtained using oligomers from di-Gly to penta-Gly. In addition to an expected increase of the configurational entropy and size-dependent van der Waals force, the increasing number of polar peptide bonds, among others, may be responsible for this observation. The effect of chain length was also investigated by performing similar experiments using_L-lysine vs. poly-_L-lysine (PLL), and_L-glutamic acid vs. poly-_L-glutamic acid. The results suggest that longer oligomers/polymers of amino acids can be preferentially adsorbed on pyrite surfaces.
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Prebiotic geochemical automata at the intersection of radiolytic chemistry, physical complexity, and systems biology

Adam Zachary R., Fahrenbach Albert C., Kacar Betul, Aono Masashi

Complexity 2018 2018年01月

ISSN 1076-2787

　概要を見る

The tractable history of life records a successive emergence of organisms composed of hierarchically organized cells and greater degrees of individuation. The lowermost object level of this hierarchy is the cell, but it is unclear whether the organizational attributes of living systems extended backward through prebiotic stages of chemical evolution. If the systems biology attributes of the cell were indeed templated upon prebiotic synthetic relationships between subcellular objects, it is not obvious how to categorize object levels below the cell in ways that capture any hierarchies which may have preceded living systems. In this paper, we map out stratified relationships between physical components that drive the production of key prebiotic molecules starting from radiolysis of a small number of abundant molecular species. Connectivity across multiple levels imparts the potential to create and maintain far-from-equilibrium chemical conditions and to manifest nonlinear system behaviors best approximated using automata formalisms. The architectural attribute of "information hiding" of energy exchange processes at each object level is shared with stable, multitiered automata such as digital computers. These attributes may indicate a profound connection between the system complexity afforded by energy dissipation by subatomic level objects and the emergence of complex automata that could have preceded biological systems.
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