122 research outputs found

    Diffusion-Controlled Recrystallization of Water Sorbed into Poly(meth)acrylates Revealed by Variable-Temperature Mid-Infrared Spectroscopy and Molecular Dynamics Simulation.

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    Recrystallization behaviors of water sorbed into four poly(meth)acrylates, poly(2-methoxyethyl acrylate), poly(tetrahydrofurfuryl acrylate), poly(methyl acrylate), and poly(methyl methacrylate), are investigated by variable-temperature mid-infrared (VT-MIR) spectroscopy and molecular dynamics (MD) simulation. VT-MIR spectra demonstrate that recrystallization temperatures of water sorbed into the polymers are positively correlated with their glass-transition temperatures reported previously. The present MD simulation shows that a lower-limit temperature of the diffusion for the sorbed water and the glass-transition temperatures of the polymers also have a positive correlation, indicating that the recrystallization is controlled by diffusion mechanism rather than reorientation mechanism. Detailed molecular processes of not only recrystallization during rewarming but also crystallization during cooling and hydrogen-bonding states of water in the polymers are systematically analyzed and discussed

    Experimental and theoretical evidence for bilayer-by-bilayer surface melting of crystalline ice

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    On the surface of water ice, a quasi-liquid layer (QLL) has been extensively reported at temperatures below its bulk melting point at 273 K. Approaching the bulk melting temperature from below, the thickness of the QLL is known to increase. To elucidate the precise temperature variation of the QLL, and its nature, we investigate the surface melting of hexagonal ice by combining noncontact, surface-specific vibrational sum frequency generation (SFG) spectroscopy and spectra calculated from molecular dynamics simulations. Using SFG, we probe the outermost water layers of distinct single crystalline ice faces at different temperatures. For the basal face, a stepwise, sudden weakening of the hydrogen-bonded structure of the outermost water layers occurs at 257 K. The spectral calculations from the molecular dynamics simulations reproduce the experimental findings; this allows us to interpret our experimental findings in terms of a stepwise change from one to two molten bilayers at the transition temperature

    High-resolution seismic reflection survey across the Western Boundary Fault Zone of the Nagano Basin, Central Japan: Data acquisition and processing

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    The Western Boundary Fault Zone of the Nagano Basin borders the eastern margin of Northern Fossa Magna, which has undergone strong horizontal shortening since Pliocene. The Western Boundary Fault Zone of the Nagano Basin is considered to be a back thrust that developed on the hanging wall side of the Itoigawa-Shizuoka Tectonic Line. To reveal the subsurface structure of the Western Boundary Fault Zone of the Nagano Basin, we carried out a high-resolution seismic reflection survey along the Saigawa River, southern Nagano City. The source used in this survey was a mini-vibrator (T-15000). Source and receiver spacing was 10 m. 180 channels of geophone arrays were used to record each shot. The seismic section obtained after careful data processing shows fairly flat Quaternary basin fillings in the eastern part of the seismic line. The Quaternary basin fillings are interpreted to be in west-dipping fault contact with west-dipping Neogene strata underlying the Saigawa Hills

    The Discovery of LOX-1, its Ligands and Clinical Significance

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    LOX-1 is an endothelial receptor for oxidized low-density lipoprotein (oxLDL), a key molecule in the pathogenesis of atherosclerosis.The basal expression of LOX-1 is low but highly induced under the influence of proinflammatory and prooxidative stimuli in vascular endothelial cells, smooth muscle cells, macrophages, platelets and cardiomyocytes. Multiple lines of in vitro and in vivo studies have provided compelling evidence that LOX-1 promotes endothelial dysfunction and atherogenesis induced by oxLDL. The roles of LOX-1 in the development of atherosclerosis, however, are not simple as it had been considered. Evidence has been accumulating that LOX-1 recognizes not only oxLDL but other atherogenic lipoproteins, platelets, leukocytes and CRP. As results, LOX-1 not only mediates endothelial dysfunction but contributes to atherosclerotic plaque formation, thrombogenesis, leukocyte infiltration and myocardial infarction, which determine mortality and morbidity from atherosclerosis. Moreover, our recent epidemiological study has highlighted the involvement of LOX-1 in human cardiovascular diseases. Further understandings of LOX-1 and its ligands as well as its versatile functions will direct us to ways to find novel diagnostic and therapeutic approaches to cardiovascular disease

    The spotted gar genome illuminates vertebrate evolution and facilitates human-teleost comparisons

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    To connect human biology to fish biomedical models, we sequenced the genome of spotted gar (Lepisosteus oculatus), whose lineage diverged from teleosts before teleost genome duplication (TGD). The slowly evolving gar genome has conserved in content and size many entire chromosomes from bony vertebrate ancestors. Gar bridges teleosts to tetrapods by illuminating the evolution of immunity, mineralization and development (mediated, for example, by Hox, ParaHox and microRNA genes). Numerous conserved noncoding elements (CNEs; often cis regulatory) undetectable in direct human-teleost comparisons become apparent using gar: functional studies uncovered conserved roles for such cryptic CNEs, facilitating annotation of sequences identified in human genome-wide association studies. Transcriptomic analyses showed that the sums of expression domains and expression levels for duplicated teleost genes often approximate the patterns and levels of expression for gar genes, consistent with subfunctionalization. The gar genome provides a resource for understanding evolution after genome duplication, the origin of vertebrate genomes and the function of human regulatory sequences

    High-resolution seismic reflection profiling across the Shiraiwa fault, eastern margin of the Yokote basin fault zone, northeast Japan : data acquisition and processing

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    The eastern margin of the Yokote basin fault zone extends about 56km at the western foot of the Ou Backbone Range, northeast Japan. The Rikuu earthquake (M=7.2) occurred in the Ou Backbone Range (Mahiru Range) on 31st August, 1896. Associated with this earthquake, four thrust faults-Obonai, Shiraiwa, Ota, and Senya fault3 appeared on the surface of the western foot of the Mahiru Range. These faults were highly sinuous with numerous gaps and en echelon steps. We conducted a high-resolution seismic reflection profiling survey across the Shiraiwa fault. The obtained seismic reflection data were processed by conventional common mid-point methods, post-stack migration, and depth conversion. The subsurface structure across the Shraiwa fault is characterized by branched low-angle reverse faults and conjugate back-thrust. The emergent thrust associated with the 1896 earthquake is regarded to be a subsidiary reverse fault

    Theoretical Study of Structure, Spectroscopy, and Transport at Liquid Interfaces

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    ギャクダンソウ ウンドウ ニ ヨリ ケイセイサレル ヘンドウ チケイ ノ ケイセイ シンカ カテイ : ノウビ イセ ダンソウタイ ニ オケル ジレイ ケンキュウ

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    京都大学0048新制・課程博士博士(理学)甲第9316号理博第2451号新制||理||1260(附属図書館)UT51-2002-G74京都大学大学院理学研究科地球惑星科学専攻(主査)教授 岡田 篤正, 教授 竹村 恵二, 教授 梅田 康弘学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDA
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