Evolution of Frictional Behavior of Punchbowl Fault Gouges Sheared at Seismic Slip Rates and Mechanical and Hydraulic Properties of Nankai Trough Accretionary Prism Sediments Deformed at Different Loading Paths

Frictional measurements were made on natural fault gouge at seismic slip rates using a high-speed rotary-shear apparatus to study effects of slip velocity, acceleration, displacement, normal stress, and water content. Thermal-, mechanical-, and fluid-flowcoupled FEM models and microstructure observations were implemented to analyze experimental results. Slightly sheared starting material (Unit 1) and a strongly sheared and foliated gouge (Unit 2) are produced when frictional heating is insignificant and the coefficient of sliding friction is 0.4 to 0.6. A random fabric gouge with rounded prophyroclasts (Unit 3) and an extremely-fine, microfoliated layer (Unit 4) develop when significant frictional heating occurs at greater velocity and normal stress, and the coefficient of sliding friction drops to approximately 0.2. The frictional behavior at coseismic slip can be explained by thermal pressurization and a temperature-dependent constitutive relation, in which the friction coefficient is proportional to 1/T and increases with temperature (temperature-strengthening) at low temperature conditions and decreases with temperature (temperature-weakening) at higher temperature conditions. The friction coefficient, normal stress, pore pressure, and temperature within the gouge layer vary with position (radius) and time, and they depend largely on the frictional heating rate. The critical displacement for dynamic weakening is approximately 10 m or less, and can be understood as the displacement required to form a localized slip zone and achieve a steady-state temperature condition. The temporal and spatial evolution of hydromechanical properties of recovered from the Nankai Trough (IODP NanTroSEIZE Stage 1 Expeditions) have been investigated along different stress paths, which simulate the natural conditions of loading during sedimentation, underthrusting, underplating, overthrusting, and exhumation in subduction systems. Porosity evolution is relatively independent of stress path, and the sediment porosity decreases as the yield surface expands. In contrast, permeability evolution depends on the stress path and the consolidation state, e.g., permeability reduction by shear-enhanced compaction occurs at a greater rate under triaxialcompression relative to uniaxial-strain and isotropic loading. In addition, experimental yielding of sediment is well described by Cam-Clay model of soil mechanics, which is useful to better estimate the in-situ stress, consolidation state, and strength of sediment in nature

Evolution of Frictional Behavior of Punchbowl Fault Gouges Sheared at Seismic Slip Rates and Mechanical and Hydraulic Properties of Nankai Trough Accretionary Prism Sediments Deformed at Different Loading Paths

Frictional measurements were made on natural fault gouge at seismic slip rates using a high-speed rotary-shear apparatus to study effects of slip velocity, acceleration, displacement, normal stress, and water content. Thermal-, mechanical-, and fluid-flowcoupled FEM models and microstructure observations were implemented to analyze experimental results. Slightly sheared starting material (Unit 1) and a strongly sheared and foliated gouge (Unit 2) are produced when frictional heating is insignificant and the coefficient of sliding friction is 0.4 to 0.6. A random fabric gouge with rounded prophyroclasts (Unit 3) and an extremely-fine, microfoliated layer (Unit 4) develop when significant frictional heating occurs at greater velocity and normal stress, and the coefficient of sliding friction drops to approximately 0.2. The frictional behavior at coseismic slip can be explained by thermal pressurization and a temperature-dependent constitutive relation, in which the friction coefficient is proportional to 1/T and increases with temperature (temperature-strengthening) at low temperature conditions and decreases with temperature (temperature-weakening) at higher temperature conditions. The friction coefficient, normal stress, pore pressure, and temperature within the gouge layer vary with position (radius) and time, and they depend largely on the frictional heating rate. The critical displacement for dynamic weakening is approximately 10 m or less, and can be understood as the displacement required to form a localized slip zone and achieve a steady-state temperature condition. The temporal and spatial evolution of hydromechanical properties of recovered from the Nankai Trough (IODP NanTroSEIZE Stage 1 Expeditions) have been investigated along different stress paths, which simulate the natural conditions of loading during sedimentation, underthrusting, underplating, overthrusting, and exhumation in subduction systems. Porosity evolution is relatively independent of stress path, and the sediment porosity decreases as the yield surface expands. In contrast, permeability evolution depends on the stress path and the consolidation state, e.g., permeability reduction by shear-enhanced compaction occurs at a greater rate under triaxialcompression relative to uniaxial-strain and isotropic loading. In addition, experimental yielding of sediment is well described by Cam-Clay model of soil mechanics, which is useful to better estimate the in-situ stress, consolidation state, and strength of sediment in nature

Hydrogen-bond-assisted stereocontrol in the radical polymerization of N-isopropylacrylamide with bidentate Lewis base

Radical polymerization of N-isopropylacrylamide (NIPAAm) in toluene was investigated in the presence of bidentate Lewis base such as diphosphonates. Isotacticity of the obtained poly(NIPAAm)s slightly increased at –80°C, whereas syndiotactic-rich poly(NIPAAm)s were obtained at –40 to 0°C. This result corresponded to the results observed in the presence of primary alkyl phosphates. NMR analysis revealed that NIPAAm monomer and tetraisopropyl methylenebisphosphonate formed mono-binding hydrogen-bond-assisted complex at 0°C, but a chelate complex at –80°C. Thus, it was concluded that the stereospecificity in NIPAAm polymerization strongly depended on the complexation mode of the added bidentate Lewis base

Stereocontrol in NIPAAm polymerization

Radical polymerizations of N-isopropylacrylamide (NIPAAm) were carried out in toluene at low temperatures in the presence of phosphoric acid esters such as trimethyl, triethyl (TEP), tri-n-propyl, and tri-n-butyl phosphates (TBP). Syndiotactic-rich poly(NIPAAm)s were obtained at the temperature range from –60°C to 0°C, and particularly TEP provided the highest syndiotacticity (racemo diad = 65%) at –40°C. On the other hand, lowering temperature reversed the stereoselectivity of the propagation reaction so that isotactic-rich poly(NIPAAm)s were obtained at –80°C. In particular, TBP exhibited the most isotactic-specificity (meso diad = 57%). Job's plots for NIPAAm-TBP mixtures revealed that NIPAAm and TBP formed 1:1 complex at 0°C and predominantly 1:2 complex at –80°C through a hydrogen-bonding interaction. Therefore, it is considered that the stereospecificity of NIPAAm polymerization should depend on the stoichiometry of the hydrogen-bond-assisted complex. Thus, the mechanism for the present polymerization system was discussed

HYDROGEN-BOND-ASSISTED STEREOCONTROL

Radical polymerization of N-isopropylacrylamide (NIPAAm) in toluene at low temperatures was investigated in the presence of triisopropyl phosphate (TiPP). The addition of TiPP induced a syndiotactic-specificity that was enhanced by lowering polymerization temperature, whereas atactic polymers were obtained in the absence of TiPP regardless of temperature. Syndiotactic-rich poly(NIPAAm) with racemo diad = 65% was obtained at –60°C with a fourfold amount of TiPP, but almost atactic poly(NIPAAm)s were obtained by lowering temperature to –80°C. This result contrasted with the result in the presence of primary alkyl phosphates, such as tri-n-propyl phosphate, that stereospecificity varied from syndiotactic to isotactic by lowering polymerization temperature. NMR analysis at –80°C revealed that TiPP predominantly formed 1:1 complex with NIPAAm, although primary alkyl phosphates preferentially formed 1:2 complex with NIPAAm. Thus, it was concluded that a slight increase in bulkiness of the added phosphates influenced the stoichiometry of the NIPAAm-phosphate complex at lower temperatures and consequently a drastic change in the effect on stereospecificity of NIPAAm polymerization was observed

Dual Roles of Alkyl Alcohols as Syndiotactic-Specificity-Inducer and Accelerator in the Radical Polymerization of N-Isopropylacrylamide and Some Properties of Syndiotactic Poly(N-isopropylacrylamide)

Effect of simple alkyl alcohol on radical polymerization of N-isopropylacrylamide (NIPAAm) in toluene at low temperatures was investigated. We succeeded in induction of syndiotactic-specificity and acceleration of polymerization reaction at the same time by adding simple alkyl alcohols such as 3-methyl-3-pentanol (3Me3PenOH) into NIPAAm polymerization. The diad syndiotacticity increased with a decrease in temperature and an increase in bulkiness of the added alcohol, and reached up to 71% at –60°C in the presence of 3Me3PenOH. With the aide of NMR analysis, it was revealed that alcohol compounds play dual roles in this polymerization system; alcohol compound coordinating to N-H proton induces the syndiotactic-specificity and that hydrogen-bonded to C=O oxygen accelerates the polymerization reaction. The effect of syndiotacticity on properties of poly(NIPAAm)s was also discussed in some detail

Mice Transgenic for KitV620A: Recapitulation of Piebaldism but not Progressive Depigmentation Seen in Humans with this Mutation

Piebaldism is an autosomal dominant genetic pigmentary disorder, characterized by congenital white hair and patches located on the forehead, anterior trunk, and extremities. Most piebald patients have a mutation of the KIT gene, which encodes a tyrosine kinase receptor involved in pigment cell development. The white hair and patches of such patients are already completely formed at birth and do not usually expand thereafter. This stability of pigmented spots also applies to KitW and KitlSl mutant mice. However, two novel cases of piebaldism were reported in 2001, in which both mother and daughter having a novel Val620Ala mutation in their KIT gene showed progressive depigmentation. To prepare an animal model of this mutation, to explore undefined functions of KIT signaling for maintaining pigmented melanocytes in the skin or more specifically the integrity of the melanocyte stem cell system in the postnatal skin, we produced transgenic mice expressing Val620Ala Kit. These mice well mimicked the white spotting pattern of patients; however, no change in this pattern was observed after birth, even after increasing the transgene expression by various means. Here, we report the unexpectedly extremely stable maintenance of the melanocyte stem cell system under stringent conditions for KIT signaling

回転せん断試験による砂礫粒子の破砕特性評価

砂礫粒子の破砕特性を評価するために，粒子形状の角張った山砂と丸い川砂の二種類の試料を用い，回転数，回転速度，拘束圧を変化させて回転せん断試験を実施した．また，試験前後の試料の粒度分析を行った．その結果，どの条件でも十分にせん断が進行すれば，間隙比とせん断応力比，試料の粒度分析から得られるフラクタル次元は，同様の定常状態に達すること，粒子破砕およびそれに伴う体積圧縮は，回転の比較的初期の段階でより顕著に進行すること，回転速度の変化は今回の実験条件の範囲(0.21≦γ≦210(1/s))ではせん断応力，間隙比の変化に顕著な影響を及ぼさないことなどがわかった．その上で，二試料の単粒子破砕実験結果を基に，回転せん断試験の結果を系統的に評価できるマイクロメカニックスモデルの構築を行い，せん断に伴う体積圧縮は，間隙率とせん断ひずみが両対数で直線的な関係があること，圧縮が顕著に始まるせん断ひずみは，与える拘束圧と単粒子破砕強度の比によって表現されること示した

看護基礎教育における心肺蘇生法の習得状況-一次救命処置を中心として-

長崎大学医療技術短期大学部看護学科学生70名を対象に，救急蘇生訓練用人形を用いて，一次救命処置を中心とした心肺蘇生法の学内演習を行った．実技テスト，演習前後の客観テスト，学生の自己評価などをもとに学習効果および今後の課題を検討した．　実技テストでは，チェックリストにそって，各項目ごとに教官が評価した結果，ほとんどの項目で9割以上の学生が合格できた．客観テストでは演習後の平均点は高かったが，知識と技術の統合がされていない項目もあり，指導上の課題と考えられた．また，学生の自己評価では，人工呼吸法が「できなかった」とする学生が多く，気道の確保および維持，また吹き込みもかなり難しい技術であった．一次救命処置は緊急の現場で実践できなければ意昧のない技術であり，反復訓練による習得が必要であると考えられた．Nursing skill training for cardiopulmonary resuscitation as part of the basic life support was conducted in the school using dummies for training emergency resuscitation. This training was participated by 70 students of the Department of Nursing, the School of Allied Medical Sciences, Nagasaki University. The effectiveness of learning and practicing by the students and the problems were analyzed on the basis of their nursing practical test and objective tests before and after the skill exercise. In nursing practical skill test, the instructors evaluated each item on the check list, and more than 90% of the students passed the test for most of the items. In objective test, the average marks after the nursing skill exercise was high. However, knowledge and skill were not integrated in some items, leaving problems for the teaching procedure. In self-evaluation, many students "could not" perform artificial respiration, indicating that keeping airway and mouth-to-mouth ventilation were quite difficult. Basic life support is meaningless if one is unable to perform at an emergency circumstance. Acquisition of the skill by repeated training is considered essential