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Journal of Earth Science 2010年第5期21卷 801-810页

作者： Yusuke Usui Taku tsuchiya Geodynamics Research Center Ehime University

Ab initio two-phase molecular dynamics simulations were performed on silica at pressures of 20-160 GPa and temperatures of 2 500-6 000 K to examine its solid-liquid phase boundary. Results indicate a melting temperature （Tin） of 5 900 K at 135 GPa. This is 1 100 K higher than the temperature considered for the core-mantle boundary （CMB） of about 3 800 K. The calculated melting temperature is fairly consistent with classical MD （molecular dynamics） simulations. For liquid silica, the O-O coordination number is found to be 12 along the Tm and is almost unchanged with increasing pressure. The self-diffusion coefficients of O and Si atoms are determined to be 1.3×10^-9-3.3×10^-9 m2/s, and the viscosity is 0.02-0.03 Pa＇s along the Tin. We find that these transport properties depend less on pressure in the wide range up of more than 135 GPa. The eutectic temperatures in the MgO-SiO2 systems were evaluated and found to be 700 K higher than the CMB temperature, though they would decrease considerably in more realistic mantle compositions.

关键词： Ab Initio Two-Phase Molecular Dynamics on the Melting Curve of SiO2 SiO CMB MgO than

Crystal orientation-dependent fatigue characteristics in micrometer-sized single-crystal silicon

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Microsystems & Nanoengineering 2016年第1期2卷 154-162页

作者： Tsuyoshi Ikehara Toshiyuki tsuchiya National Institute of Advanced Industrial Science and Technology(AIST) 1-2 NamikiTsukubaIbaraki 305-8564Japan Department of Micro Engineering Graduate School of EngineeringKyoto UniversityKyotodaigaku-Katsura C3Nishikyo-kuKyoto 615-8540Japan

Repetitive bending fatigue tests were performed using five types of single-crystal silicon specimens with different crystal orientations fabricated from{100}and{110}*** lifetimes in a wide range between 100 and 1010 were obtained using fan-shaped resonator test *** surface observation via scanning electron microscope(SEM)revealed that the{111}plane was the primary fracture *** crack propagation exponent n was estimated to be 27,which was independent of the crystal orientation and dopant concentration;however,it was dependent on the surface conditions of the etched *** fatigue strengths relative to the deflection angle were orientation dependent,and the ratios of the factors obtained ranged from 0.86 to *** strength factors were compared with those obtained from finite element method stress *** calculated stress distributions showed strong orientation dependence,which was well-explained by the elastic *** comparison of the strength factors suggested that the first principal stress was a good criterion for fatigue *** include comparisons with specimens tested in our previous report and address the tensile strength,initial crack length,volume effect,and effects of surface roughness such as scallops.

关键词： fatigue fracture lifetime MEMS reliability resonator single-crystal silicon

Expanding-contracting Earth

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

作者： Taku tsuchiya Kenji Kawai 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 km larger than that of the present Earth immediately after the consolidation of the magma-ocean on the surface, and subsequent shrinkage of about 110 km in radius within about 10 m.y., followed by gradual expansion of 11 km 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 km in radius, presumably by the end of the Archean. Since then, the Earth has gradually cooled down to reduce its radius by around 12 km. 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 km thickness）. 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 km 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 Eukaryotes

Field observations of debris-flow initiation processes on sediment deposits in a previous deep-seated landslide site

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Journal of Mountain Science 2016年第2期13卷 213-222页

作者： Fumitoshi IMAIZUMI Satoshi tsuchiya Okihiro OHSAKA Department of Environment and Forest Resources Science Faculty of AgricultureShizuoka University

Although information regarding the initiation processes of debris flows is important for the development of mitigation measures,field data regarding these processes are *** conducted field observations of debris-flow initiation processes in the upper Ichinosawa catchment of the Ohya landslide,central *** 19 June 2012,our videocamera monitoring systems recorded the moment of debris-flow initiation on channel deposits(nine surges) and talus slopes(eight surges).The initiation mechanisms of these surges were classified into three types by analyzing the video images: erosion by the surface flow,movement of deposits as a mass,and upward development of the fluid *** first type was associated with the progress of surface flow from the upper stream on unsaturated channel *** second type was likely caused by an increase in the pore water pressure associated with the rising in the groundwater level in channel deposits;a continuous water supply from the upper stream by the surface flow might have induced this *** third type was associated with changes in the downstream topography caused by *** flow velocity of most surges was less than 3 m s^(-1) and they usually stopped within 100 m from the initiation *** with abundant pore fluid had a higher flow velocity(about 3- 5 m s^(-1)) and could travel for alonger *** observations indicate that the surface flow plays an important role in the initiation of debris flows on channel deposits and talus slopes.

关键词： Debris flow Initiation zone Field monitoring Ohya landslide

Anticancer effect of adenosine on gastric cancer via diverse signaling pathways

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World Journal of Gastroenterology 2015年第39期21卷 10931-10935页

作者： Ayako tsuchiya Tomoyuki Nishizaki Division of Bioin- formation Department of Physiology Hyogo College of Medicine

Extracellular adenosine induces apoptosis in a variety of cancer cells via intrinsic and extrinsic pathways. In the former pathway, adenosine uptake into cells triggers apoptosis, and in the latter pathway, adenosine receptors mediate apoptosis. Extracellular adenosine also inducesapoptosis of gastric cancer cells. Extracellular adenosine is transported into cells through an adenosine transporter and converted to AMP by adenosine kinase. In turn, AMP activates AMP-activated protein kinase(AMPK). AMPK is the factor responsible for caspase-independent apoptosis of GT3-TKB gastric cancer cells. Extracellular adenosine, on the other hand, induces caspase-dependent apoptosis of MKN28 and MKN45 gastric cancer cells by two mechanisms. Firstly, AMP, converted from intracellularly transported adenosine, initiates apoptosis, regardless of AMPK. Secondly, the A3 adenosine receptor, linked to Gi/Gq proteins, mediates apoptosis by activating the Gq protein effector, phospholipase Cγ, to produce inositol 1,4,5-trisphosphate and diacylglycerol, which activate protein kinase C. Consequently, the mechanisms underlying adenosine-induced apoptosis vary, depending upon gastric cancer cell types. Understand the contribution of each downstream target molecule of adenosine to apoptosis induction may aid the establishment of tailor-made chemotherapy for gastric cancer.

关键词： Adenosine Apoptosis Intrinsic pathway Extrinsic pa

Liver stem cells:Plasticity of the liver epithelium

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World Journal of Gastroenterology 2019年第9期25卷 1037-1049页

作者： Atsunori tsuchiya Wei-Yu Lu Division of Gastroenterology and Hepatology Graduate school of medical and dental sciences Niigata University Centre for Liver and Gastrointestinal Research Institute of Immunology and Immunotherapy the University of Birmingham

The liver has a high regenerative capacity after acute liver injury, but this is often impaired during chronic liver injury. The existence of a dedicated liver stem cell population that acts as a source of regeneration during chronic liver injury has been controversial. Recent advances in transgenic models and cellular reprogramming have provided new insights into the plasticity of the liver epithelium and directions for the development of future therapies. This article will highlight recent findings about the cellular source of regeneration during liver injury and the advances in promoting liver regeneration.

关键词： Liver regeneration Stem cells Cellular plasticity

Martensitic stabilization and defects induced by deformation in TiNi shape memory alloys

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International Journal of Minerals,Metallurgy and Materials 2011年第1期18卷 66-69页

作者： Shuai Wang Koichi tsuchiya Lei Wang Minoru Umemoto Key Laboratory for Anisotropy and Texture of Materials Northeastern University Shenyang 110819 China Structural Functions Research Group Innovative Materials Engineering Laboratory National Institute for Materials Science Tsukuba 305-0047 Japan Department of Production Systems Engineering Toyohashi University of Technology Toyohashi 441-8580 Japan

Martensitic stabilization caused by deformation in a TiNi shape memory alloy was *** attention was paid to the deformed microstructures to identify the cause of martensitic *** stabilization was demonstrated by differential scanning calorimetry for the tensioned TiNi shape memory *** electron microscopy revealed that antiphase boundaries were formed because of the fourfold dissociation of [110]B19＇ super lattice dislocations and were preserved after reverse transformation due to the lattice *** stabilization was attributed to dislocations induced by deformation,which reduced the ordering degree of the microstructure,spoiled the reverse path from martensite to parent phase compared with thermoelastic transformation,and imposed resistance on phase transformation through the stress field.

关键词： shape memory alloys transmission electron microscopy martensitic transformations stabilization defects

Deformation Mechanism and Stabilization of Martensite in TiNi Shape Memory Alloy

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Journal of Materials Science & Technology 2010年第10期26卷 936-940页

The deformed microstructures of a TiNi shape memory alloy were investigated in present study to clarify the deformation *** is found that the stress-strain curve was divided into three stages based on the deformation *** cause of martensitic stabilization effect was also interpreted by paying special attention to the deformed *** electron microscopic examination revealed that at the early stage of deformation martensitic reorientation and compound twinning relieved some of the elastic strain energy stored in martensite,and this contributes to the martensitic stabilization ***,when deformation strain became larger,the density of dislocations increased *** boundaries were also *** degree of ordering was therefore decreased due to dislocations and antiphase *** disordering was another cause of martensitic stabilization *** the middle stage of deformation martensitic stabilization was attributed to the two reasons above.

关键词： TiNi shape memory alloy Transmission electron microscopy Ordering Dislocation Martensitic transformation

Dedifferentiated chondrosarcoma of the middle finger arising from a solitary enchondroma:A case report

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World Journal of Clinical Cases 2022年第10期10卷 3297-3305页

作者： Hirotaka Yonezawa Norio Yamamoto Katsuhiro Hayashi Akihiko Takeuchi Shinji Miwa Kentaro Igarashi Sei Morinaga Yohei Asano Shiro Saito Yasunori Tome Hiroko Ikeda takayuki Nojima Hiroyuki tsuchiya Department of Orthopaedic Surgery Graduate School of Medical SciencesKanazawa UniversityKanazawa 920-8641IshikawaJapan Department of Orthopedic Surgery Graduate School of MedicineUniversity of the RyukyusNishihara 903-0215OkinawaJapan Department of Diagnostic Pathology Kanazawa University HospitalKanazawa 920-8641IshikawaJapan

BACKGROUND Dedifferentiated chondrosarcoma(DDCS)accounts for 10%of all chondrosarcomas and has the poorest outcome,with a 5-year survival rate of 7%-25%.DDCS commonly occurs in the femur and pelvis,whereas DDCS of the finger is extremely ***,the histological findings of preexisting solitary enchondroma samples are important and valuable for diagnosing malignant *** SUMMARY We report our experience with DDCS in the proximal phalanx of the left middle finger of an 87-year-old *** had undergone surgery for enchondroma,with curettage and artificial bone grafting,11 years ago,in the same *** years after the primary surgery,the left middle finger gradually started to enlarge,and the growth speed increased in the past *** radiographs showed an expansive osteolytic lesion with calcifications and residual grafting *** to the suspicion of malignancy,we performed ray *** findings revealed an abrupt transition between the low-grade chondrosarcoma and dedifferentiated sarcoma *** dedifferentiated components showed the features of a high-grade undifferentiated pleomorphic *** patient was diagnosed with DDCS arising from a preexisting *** had no local recurrence or distant metastasis and died of pneumonia 6 years and 10 months after the second *** The histological findings of a precursor lesion showed a typical enchondroma,suggesting that DDCS can arise from enchondroma.

关键词： Dedifferentiated chondrosarcoma Enchondroma Finger Phalanx Ray amputation Case report