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Origins of building block. of life: A review

Geoscience Frontiers 2018年第4期9卷 1117-1153页

作者： Norio k.tadai Shigenori maruyama Earth-Life Science Institute Tokyo Institute of Technology

How and where did life on Earth originate？ To date, various environments have been proposed as plausible sites for the origin of life. However, discussions have focused on a limited stage of chemical evolution, or emergence of a specific chemical function of proto-biological systems. It remains unclear what geochemical situations could drive all the stages of chemical evolution, ranging from condensation of simple inorganic compounds to the emergence of self-sustaining systems that were evolvable into modern biological ones. In this review, we summarize reported experimental and theoretical findings for prebiotic chemistry relevant to this topic, including availability of biologically essential elements（N and P） on the Hadean Earth, abiotic synthesis of life＇s building block.（amino acids, peptides, ribose, nucleobases, fatty acids, nucleotides, and oligonucleotides）, their polymerizations to bio-macromolecules（peptides and oligonucleotides）, and emergence of biological functions of replication and compartmentalization. It is indicated from the overviews that completion of the chemical evolution requires at least eight reaction conditions of（1） reductive gas phase,（2） alk.line pH,（3） freezing temperature,（4）fresh water,（5） dry/dry-wet cycle,（6） coupling with high energy reactions,（7） heating-cooling cycle in water, and（8） extraterrestrial input of life＇s building block. and reactive nutrients. The necessity of these mutually exclusive conditions clearly indicates that life＇s origin did not occur at a single setting; rather, it required highly diverse and dynamic environments that were connected with each other to allow intratransportation of reaction products and reactants through fluid circulation. Future experimental research that mimics the conditions of the proposed model are expected to provide further constraints on the processes and mechanisms for the origin of life.

关键词： Astrobiology Biochemistry Chemical evolution Extraterrestrial life Hadean Earth Hydrothermal systems

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Nuclear geyser model of the origin of life:Driving force to promote the synthesis of building block. of life

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Geoscience Frontiers 2017年第2期8卷 275-298页

作者： Toshik.zu Ebisuzak. Shigenori maruyama RIk.N Earth-Life Science Institute Tokyo Institute of Technology

We propose the nuclear geyser model to elucidate an optimal site to bear the first *** model overcomes the difficulties that previously proposed models have *** geyser is a geyser driven by a natural nuclear reactor,which was lik.ly common in the Hadean Earth,because of a much higher abundance of 235U as nuclear *** nuclear geyser supplies the following：（1）high-density ionizing radiation to promote chemical chain reactions that even tar can be used for intermediate material to restart chemical reactions,（2）a system to maintain the circulation of material and energy,which includes cyclic environmental conditions（warm/cool,dry/wet,etc.）to enable to produce complex organic compounds,（3）a lower temperature than 100℃ as not to break.down macromolecular organic compounds,（4）a locally reductive environment depending on rock.types exposed along the geyser wall,and（5）a container to confine and accumulate volatile *** five factors are the necessary conditions that the birth place of life must *** the nuclear geyser can meet all five,in contrast to the previously proposed birth sites,such as tidal flat,submarine hydrothermal vent,and outer *** nuclear reactor and associated geyser,which maintain the circulations of material and energy with its surrounding environment,are regarded as the nuclear geyser system that enables numerous k.nds of chemical reactions to synthesize complex organic compounds,and where the most primitive metabolism could be generated.

关键词： Origin of life Chemical evolution Natural nuclear reactor Aqueous electron Radiation chemistry

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United theory of biological evolution:Disaster-forced evolution through Supernova,radioactive ash fall-outs,genome instability,and mass extinctions

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Geoscience Frontiers 2015年第1期6卷 103-119页

作者： Toshik.zu Ebisuzak. Shigenori maruyama RIk.N 2-1Hirosawa Earth-Life Science Institute Tokyo Institute of Technology

We present the disaster-forced biological evolution model as a general framework.that includes Darwinian ＂phylogenic gradualism＂, Eldredge-Gould＇s ＂punctuated equilibrium＂, mass extinctions, and allopatric, parapatric, and sympatric speciation. It describes how reproductive isolation of organisms is established through global disasters due to supernova encounters and local disasters due to radioactive volcanic ash fall-outs by continental alk.line volcanism. Our new evolution model uniquely highlights three major factors of disaster-forced speciation： enhanced mutation rate by higher natural radiation level, smaller population size, and shrunk.n habitat size （i.e., isolation among the individual pop- ulations）. We developed a mathematical model describing speciation of a half-isolated group from a parental group, tak.ng into account the population size （Ne）, immigration rate （m）, and mutation rate （μ）. The model gives a quantitative estimate of the speciation, which is consistent with the observations of speciation speed. For example, the speciation tak.s at least 105 generations, if mutation rate is less than 10 3 per generation per individual. This result is consistent with the previous studies, in which μ is assumed to be 10 3-10-5. On the other hand, the speciation is much faster （less than l0S generations） for the case that μ is as large as 0.1 in parapatric conditions （m 〈 μ）. Even a sympatric （m ~ 1 ） speciatiou can occur within 103 generations, if mutation rate is very high （μ- 1 mutation per individual per generation）, and if Ne 〈 20-30. Such a high mutation rate is possible during global disasters due to supernova encounters and local disasters due to radioactive ash fall-outs. They raise natural radiation level by a factor of 100-1000. Such rapid speciation events can also contribute to macro-evolution during mass extinction events, such as observed during the Cambrian explosion of biodiversity. A similar rapid speciation （though in a much smaller scale）

关键词： Speciation Supernova encounter Continental alk.line volcanism Cichlid Great African ape Cambrian explosion

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Formation of anorthosite on the Moon through magma ocean fractional crystallization

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Geoscience Frontiers 2017年第2期8卷 299-308页

作者： Tatsuyuk. Arai Shigenori maruyama Department of Earth and Planetary Sciences Tokyo Institute of Technology2-12-10okayamaMeguro-kuTokyo 152-8551Japan Earth-Life Science Institute Tokyo Institute of Technology2-12-1 OokayamaMeguro-kuTokyo 152-8551Japan

Lunar anorthosite is a major rock.of the lunar highlands,which formed as a result of plagioclasefloatation in the lunar magma ocean（LMO）.Constraints on the sufficient conditions that resulted in the formation of a thick.pure anorthosite（mode of plagioclase 〉95 vol.%） is a k.y to reveal the early magmatic evolution of the terrestrial *** form the pure lunar anorthosite,plagioclase should have separated from the magma ocean with low crystal *** network. of plagioclase and mafic minerals develop when the crystal fraction in the magma（φ） is higher than ca.40-60 vol.%,which inhibit the formation of pure *** contrast,when φ is small,the magma ocean is highly turbulent,and plagioclase is lik.ly to become entrained in the turbulent magma rather than separated from the *** determine the necessary conditions in which anorthosite forms from the LMO,this study adopted the energy criterion formulated by *** composition of melt,temperature,and pressure when plagioclase crystallizes are constrained by using MELTS/pMELTS to calculate the density and viscosity of the *** plagioclase starts to crystallize,the Mg~# of melt becomes 0.59 at 1291 *** density of the melt is smaller than that of plagioclase for P 〉 2.1 k.ar（ca.50 k. deep）,and the critical diameter of plagioclase to separate from the melt becomes larger than the typical crystal diameter of plagioclase（1.8-3 cm）.This suggests that plagioclase is lik.ly entrained in the LMO just after the plagioclase starts to *** the Mg~# of melt becomes 0.54 at 1263 C,the density of melt becomes larger than that of plagioclase even for 0 *** the Mg~# of melt decreases down to 0.46 at 1218 C,the critical diameter of plagioclase to separate from the melt becomes 1.5-2.5 cm,which is nearly equal to the typical plagioclase of the lunar *** suggests that plagioclase could separate from the *** of the differences between the Earth and the Moon is the presenc

关键词： Moon Anorthosite Magma ocean MELTS Fractional crystallization

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Current role of ultrasound for the management of hepatocellular carcinoma

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World Journal of Gastroenterology 2008年第11期14卷 1710-1719页

作者： Hitoshi maruyama Masaharu Yoshik.wa Osamu Yok.suk. Department of Medicine and Clinical Oncology Chiba University Graduate School of Medicine 1-8-1InohanaChuou-kuChiba 260-8670Japan

Hepatocellular carcinoma （HCC） has a decisive influence on the prognosis of cirrhotic patients. Although α-fetoprotein （AFP） is a k.own and specific tumor mak.r for HCC, it is not suitable for the screening and surveillance of HCC because of its poor predictive value and low sensitivity. The use of imaging modalities is essential for the screening, diagnosis and treatment of HCC. Ultrasound （US） plays a major role among them, because it provides real-time and non-invasive observation by a simple and easy technique. In addition, US-guided needle puncture methods are frequently required for the diagnosis and/or treatment process of HCC. The development of digital technology has led to the detection of blood flow by color Doppler US, and the sensitivity for detecting tumor vascularity has shown remark.ble improvement with the introduction of microbubble contrast agents. Moreover, near realtime 3-dimensional US images are now available. As for the treatment of HCC, high intensity focused ultrasound （HIFU） was developed as a novel technology that provides transcutaneous ablation effect without needle puncture. These advancements in the US field have led to rapid progress in HCC management, and continuing advances are expected. This article reviews the current application of US for HCC in clinical practice.

关键词： Ultrasound Contrast agent Hepatocellular carcinoma Liver Surveillance Treatments

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Triggers and sources of volatile-bearing plumes in the mantle transition zone

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Geoscience Frontiers 2015年第5期6卷 679-685页

作者： Inna Safonova k.nstantin Litasov Shigenori maruyama V.S.Sobolev Institute of Geology and Mineralogy SB RAS Novosibirsk.State University Earth-Life Science Institute Tokyo Institute of Technology

The paper discusses generation of volatile-bearing plumes in the mantle transition zone(MTZ) in terms of mineral-fluid petrology and their related formation of numerous localities of intra-plate bimodal volcanic series in Central and East *** plume generation in the MTZ can be triggered by the tectonic erosion of continental crust at Pacific-type convergent margins and by the presence of water and carbon dioxide in the *** probable sources of volatiles are the hyclrated/carbonated sediments and basalts and serpentinite of oceanic slabs,which can be subducted down to the deep *** erosion of continental crust supplies crustal material enriched in uranium and thorium into the mantle,which can serve source of heat in the *** heating in the MTZ induces melting of subducted slabs and continental crust and mantle upwelling,to produce OIB-type mafic and felsic melts,respectively.

关键词： Asis Pacific-type convergent margin Continental cr

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Expanding-contracting Earth

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Geoscience Frontiers 2013年第3期4卷 341-347页

作者： Tak. Tsuchiya k.nji k.wai Shigenori maruyama Geodynamic Research Center Ehime UniversityMatsuyamaEhime 790-8577Japan Department of Earth and Planetary Sciences Tokyo Institute of TechnologyMeguroTokyo 152-8551Japan Department of Earth Science University of CaliforniaSanta Barbara 93106CAUSA

The Earth was born from a giant impact at 4.56 Ga. It is generally thought that the Earth subsequently cooled, and hence shrunk. over geologic time. However, if the Earth＇s convection was double-layered, there must have been a peak.of expansion during uni-directional cooling. We computed the expansion- contraction effect using first principles mineral physics data. The result shows a radius about 120 k. larger than that of the present Earth immediately after the consolidation of the magma-ocean on the surface, and subsequent shrink.ge of about 110 k. in radius within about 10 m.y., followed by gradual expansion of 11 k. in radius due to radiogenic heating in the lower mantle in spite of cooling in the upper mantle in the Archean. This was due to double-layered convection in the Archean with final collapse of overturn with contraction of about g k. in radius, presumably by the end of the Archean. Since then, the Earth has gradually cooled down to reduce its radius by around 12 k.. Geologic evidence supports the late Archean mantle overturn ca. 2.6 Ga, such as the global distribution of super-liqnidus flood basalts on nearly all cratonic fragments （〉35 examples）. If our inference is correct, the surface environment of the Earth must have undergone extensive volcanism and emergence of local landmasses, because of the thin ocean cover （3-5 k. thick.ess）. Global unconformity appeared in cratonic fragments with stromatolite back.to 2.9 Ga with a peak.at 2.6 Ga. The global magmatism brought extensive crustal melting to yield explosive felsic volcanism to transport volcanic ash into the stratosphere during the catastrophic mantle overturn. This event seems to be recorded by sulfur mass-independent fractionation （SMIF） at 2.6 Ga. During the mantle overturn, a number of mantle plumes penetrated into the upper mantle and caused local upward doming of by ca. 2-3 k. which raised local landmasses above sea-level. The consequent increase of atmospheric oxygen enabled life evolutio

关键词： Mantle overturn Expanding Earth Global unconformity Nutrients Euk.ryotes

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Habitable Trinity

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Geoscience Frontiers 2015年第1期6卷 95-101页

作者： James M.Dohm Shigenori maruyama Earth-Life Science Institute Tokyo Institute of Technology

Habitable Trinity is a newly proposed concept of a habitable environment. This concept indicates that the coexistence of an atmosphere （consisting largely of C and N）, an ocean （H and 0）, and a landmass （supplier of nutrients） accompanying continuous material circulation between these three components driven by the Sun is one of the minimum requirements for life to emerge and evolve. The life body consists of C, O, H, N and other various nutrients, and therefore, the presence of water, only, is not a sufficient condition. Habitable Trinity environment must he maintained to supply necessary components for life body. Our Habitable Trinity concept can also be applied to other planets and moons such as Mars, Europa, Titan, and even exoplanets as a useful index in the quest for life-containing planetary bodies.

关键词： Habitable Trinity Ocean Atmosphere Landmass Sun

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Reactions between olivine and CO2-rich seawater at 300℃:Implications for H2 generation and CO2 sequestration on the early Earth

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Geoscience Frontiers 2017年第2期8卷 387-396页

作者： Hisahiro Ueda Yusuk. Sawak. Shigenori maruyama Department of Earth and Planetary Sciences Tokyo Institute of Technology2-12-1 OokayamaMeguro-kuTokyo 152-8551Japan Earth-Life Science Institute Tokyo Institute of Technology2-12-1 OokayamaMeguro-kuTokyo 152-8551Japan

To understand the influence of fluid CO2 on ultramafic rock.hosted seafloor hydrothermal systems on the early Earth,we monitored the reaction between San Carlos olivine and a CO2-rich NaCl fluid at 300 C and 500 *** the experiments,the total carbonic acid concentration（∑XO2） in the fluid decreased from approximately 65 to 9 mmol/*** minerals,magnesite,and subordinate amount of dolomite were formed via the water-rock.*** H2 concentration in the fluid reached approximately 39 mmol/k. within 2736 h,which is relatively lower than the concentration generated by the reaction between olivine and a CO2-free NaCl solution at the same *** seen in previous hydrothermal experiments using k.matiite,ferrous iron incorporation into Mg-bearing carbonate minerals lik.ly limited iron oxidation in the fluids and the resulting H2 generation during the olivine *** carbonate mineralogy over the temperature range of natural hydrothermal fields,H2 generation is lik.ly suppressed at temperatures below approximately 300℃ due to the formation of the Mg-bearing ***,H_2 concentration in fluid at 300℃ could be still high due to the temperature dependency of magnetite stability in ultramafic ***,the Mg-bearing carbonates may play a k.y role in the ocean-atmosphere system on the early *** studies suggest that the subduction of carbonated ultramafic rock. may transport surface CO2 species into the deep *** process may have reduced the huge initial amount of CO2 on the surface of the early *** approximate calculations demonstrate that the subduction of the Mg-bearing carbonates formed in k.matiite lik.ly played a crucial role as one of the CO2 carriers from the surface to the deep mantle,even in hot subduction zones.

关键词： Olivine CO2-rich condition Early Earth Hydrothermal alteration Serpentinization Experiment

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Driving force and structural strength evaluation of a flexible mechanical system with a hydrostatic sk.leton

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第4期11卷 255-262页

作者： Daisuk. maruyama Hitoshi k.MURA Michihik. k.SEk. Norio INOU Department of Mechanical and Control Engineering Tokyo Institute of Technology

The purpose of this study was to build a flexible mechanical system with a hydrostatic *** main components of this system are two type flexible *** is a structural bag with constant inner *** other is an actuator bag with controlled inner *** design the system,it was necessary to estimate both structural deformation and driving *** analysis of flexible bags,however,is difficult because of large nonlinear *** study analyzed structural strength and driving force of flexible bags with the nonlinear finite element analysis (FEA) software *** stress concentration dependency on the bag shape is described and the driving force is calculated to include the large *** the analytical results,this study derives an empirical equation of driving *** validity of the equation was confirmed by condition-changed analyses and experimental results.

关键词： Flexible mechanical system Hydrostatic sk.leton Design method Nonlinear finite element analysis (FEA)

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