F. Jonasson, A. Arnarsson, Tünde Pető, Hidekazu Sasaki, Katsuhiko SASAKI, A. Graham Bird,
Purpose To examine the age- and gender-specific 5-year incidence of age-related maculopathy (ARM) and age-related macular degeneration (AMD) in citizens of Reykjavik. Design Population-based, prospective cohort study. Participants The cohort was a population-based random sample of citizens 50 years and older. Of 1379 eligible subjects, 1045 had a baseline examination in 1996; 846 of the 958 survivors (88.2%) had a 5-year follow-up examination in 2001. Methods The incidence of various characteristics ...
Tópico(s): Glaucoma and retinal disorders
2004 - Elsevier BV | Ophthalmology
Yue Jin Shan, Katsuhiko SASAKI, Kazuhiro Sudo, Hideo Imoto, Mitsuru Itoh,
Electron doping into Cd3TeO6 with a 1:1 ordered perovskite-type structure was carried out by two methods: the introduction of oxygen vacancies, and the atomic substitution of In for Cd. Both methods turned polycrystalline samples into metallic conductors while single crystals with metallic conductivity were obtained by the second method. The resistivity and thermoelectric power of the single-crystal indium-substituted sample were 0.6 mΩ·cm and -50 µV·K-1, respectively, giving a power factor of 4× ...
Tópico(s): Magnetic and transport properties of perovskites and related materials
2002 - Institute of Physics | Japanese Journal of Applied Physics
Michio Innami, Shinya Honda, Katsuhiko SASAKI, Yoshihiro NARITA,
An accurate and straightforward analytical method is proposed for the free vibration of a laminated composite rectangular plate with blended layers. The plate with blended layers is defined here as a laminated plate where some of the outer layers are composed of multiple subareas with different orientation angles of straight fibers. A finite element code is developed as well to verify accuracy of the proposed method. In numerical comparison, the natural frequencies calculated by the present method ...
Tópico(s): Aeroelasticity and Vibration Control
2021 - Elsevier BV | Composite Structures
Katsuhiko Sasaki, Takeshi Uchiumi, Takahiro Toshima, Mikako Yagi, Yura Do, Haruka Hirai, Ko Igami, Kazuhito Gotoh, Dongchon Kang,
Mitochondrial-nuclear communication, known as retrograde signaling, is important for regulating nuclear gene expression in response to mitochondrial dysfunction. Previously, we have found that p32/C1qbp-deficient mice, which have a mitochondrial translation defect, show endoplasmic reticulum (ER) stress response and integrated stress response (ISR) gene expression in the heart and brain. However, the mechanism by which mitochondrial translation inhibition elicits these responses is not clear. Among ...
Tópico(s): RNA regulation and disease
2020 - Portland Press | Bioscience Reports
Kazuhito Gotoh, Takafumi Morisaki, Daiki Setoyama, Katsuhiko Sasaki, Mikako Yagi, Ko Igami, Soichi Mizuguchi, Takeshi Uchiumi, Yoshinori Fukui, Dongchon Kang,
Dendritic cell (DC) maturation induced by Toll-like receptor agonists requires activation of downstream signal transduction and metabolic changes. The endogenous metabolite citrate has recently emerged as a modulator of DC activation. However, the metabolic requirements that support citrate production remain poorly defined. Here, we demonstrate that p32/C1qbp, which functions as a multifunctional chaperone protein in mitochondria, supports mitochondrial metabolism and DC maturation. Metabolic analysis ...
Tópico(s): Immune Cell Function and Interaction
2018 - Cell Press | Cell Reports
K. Katagiri, Katsuhiko SASAKI, Shinya Honda, Hikaru Nakashima, Yusuke Tomizawa, Shimpei Yamaguchi, Tomoatsu Ozaki, Hirosuke Sonomura, Atsushi Kakitsuji,
A more efficient manufacturing process for CFRP is expected to save energy, time and cost for production. However, it is difficult to impregnate the resin efficiently and uniformly between the carbon fibers, micro void tend to remains and strength decreases. In this study, a novel manufacturing method of CFRP by using the electro-activated deposition resin molding was developed. The non-crimp carbon fiber fabric was immersed in the electro-activated deposition solution, that containing epoxy groups. ...
Tópico(s): Material Properties and Applications
2017 - Elsevier BV | Composite Structures
Katsuhiko Sasaki, Kazuhito Gotoh, Sho Miake, Daiki Setoyama, Mikako Yagi, Ko Igami, Takeshi Uchiumi, Dongchon Kang,
Sepsis is a major cause of morbidity and mortality in seriously ill patients and mitochondrial dysfunction is associated with poor outcomes in septic patients. Although interleukin-6 (IL-6) is a good prognostic marker for sepsis, the relationship between mitochondrial dysfunction and IL-6 remains poorly understood. We identified p32/C1QBP/HABP1 as a regulator of IL-6 production in response to lipopolysaccharide (LPS). LPS induced IL-6 overproduction in p32 deficient mouse embryonic fibroblasts (MEFs) ...
Tópico(s): Sepsis Diagnosis and Treatment
2017 - Elsevier BV | EBioMedicine
K. Katagiri, Katsuhiko SASAKI, Shinya Honda, Hikaru Nakashima, Shimpei Yamaguchi, Tomoatsu Ozaki, Hirosuke Sonomura, Atsushi Kakitsuji,
Recently, theoretical and experimental methods were proposed for organizing carbon fibers in straight and curvilinear arrangements to obtain a uniform stress distribution in the design of three-dimensional (3D) carbon fiber reinforced thermosetting plastic (CFRP). In this study, to establish an efficient CFRP manufacturing method and realize the curvilinear arrangement of carbon fibers, we develop an electrodeposition resin molding technique. That is, immersing a noncrimp fabric in the electrodeposition ...
Tópico(s): Mechanical Behavior of Composites
2017 - Elsevier BV | Composites Part A Applied Science and Manufacturing
Yusuke Tomizawa, Katsuhiko SASAKI, Akiyoshi Kuroda, Ryo Takeda, Yoshihiko Kaito,
As mobile devices become more complex and higher in performance despite the smaller size, heat concentration at localized areas has become a problem. In recent years, passive cooling using phase change materials (PCMs) has drawn attention as a thermal management method for mobile devices. PCMs reduce the temperature increase rate due to their latent heat properties. This reduction in the temperature increase rate is called a "delay effect". Moreover, microencapsulated PCMs (MPCMs) are attracting attention ...
Tópico(s): Solar Thermal and Photovoltaic Systems
2015 - Elsevier BV | Applied Thermal Engineering
Daisuke Echizenya, Hiroo SAKAMOTO, Katsuhiko SASAKI,
Solar power generation using polycrystalline silicon wafers has been rapidly growing in recent years. As a result, it is required to understand the strength characteristics of polycrystalline silicon wafers in order to enhance their quality. Scratches and material defects should be taken into consideration when strength characteristics of polycrystalline silicon are evaluated, since it is a brittle material. In this paper, bending strength of polycrystalline silicon wafers for solar cells were measured, ...
Tópico(s): Advanced Surface Polishing Techniques
2011 - Elsevier BV | Procedia Engineering
Tsuyoshi-Takahashi, Katsuhiko SASAKI,
To meet several marketing demands, development of new aluminum alloys which can be used for future high-efficiency diesel engines has been widely pursued. Especially, cylinder heads (hereafter referred to as "head(s)") are used at high combustion pressure and very high temperature, which makes it difficult to achieve a structure with light weight and high rigidity. In this study, aluminum alloy A356 (Al-Si-Mg series) which is a major head material, were conducted the thermal fatigue tests. Thus, the ...
Tópico(s): Fatigue and fracture mechanics
2010 - Elsevier BV | Procedia Engineering
Shinya Honda, Yoshihiro NARITA, Katsuhiko SASAKI,
Abstract A design method is proposed to optimize the stacking sequence of laminated composite plates for desired vibration characteristics. The objective functions are the natural frequencies of the laminated plates, and three types of optimization problems are studied where the fundamental frequency and the difference of two adjacent frequencies are maximized, and the difference between the target and actual frequencies is minimized. The design variables are a set of discrete values of fiber orientation ...
Tópico(s): Topology Optimization in Engineering
2009 - Taylor & Francis | Advanced Composite Materials
Ken-ichi OHGUCHI, Katsuhiko SASAKI, Setsuo Aso,
This paper proposes a method to estimate basic material constants in an elasto-plastic-creep constitutive model for lead-free solders by conducting only a tensile test. The test employs a stepped ramp wave loading, which repeats instantaneous strain and strain maintenance. Time-independent strains are obtained from the stress-strain relations at the instantaneously strained parts, while the time-dependent strains are obtained from the stress-time relations during the strain maintaining periods. ...
Tópico(s): Metallurgy and Material Forming
2009 - ASM International | Journal of Electronic Packaging
Shinya Honda, Yoshihiro NARITA, Katsuhiko SASAKI,
A new design method is proposed here to maximize the fundamental frequency of laminated composite plates reinforced by curvilinear fibers. Spline functions represent arbitrarily shaped fibers and the Ritz method generates frequency equations. The optimum curvilinear shapes are searched for the maximum fundamental frequencies using a genetic algorithm, and increments of data points which define the spline shape are used as design variables under the limited range of undulation. Comparison of the ...
Tópico(s): Vibration and Dynamic Analysis
2009 - Japan Society Mechanical Engineers | Journal of System Design and Dynamics
Tsuyoshi MAYAMA, Katsuhiko SASAKI, Mitsutoshi Kuroda,
This study is a quantitative evaluation of dislocation structures due to cyclic plasticity with small strain amplitudes in austenitic stainless steel 316L. First, dislocation structures in specimens after 100 cycles of cyclic loading with strain amplitudes of 0.25%, 0.75% and 1.0% were observed by transmission electron microscopy (TEM). The observations showed that cyclic loading with larger strain amplitudes results in the organization of more uniform dislocation cell structures. Secondly, an image ...
Tópico(s): Microstructure and mechanical properties
2008 - Elsevier BV | Acta Materialia
Shinya Honda, Yoshimasa Oonishi, Yoshihiro NARITA, Katsuhiko SASAKI,
In the past few decades, composite materials composed of straight fibers and polymer matrix have gained their status as the most promising material for light-weight structures. Technical merit of the composites as tailored material also provided practical advantages in the optimum design process. Recently, it is reported that the fabrication machine has been developed to make curved fibers embedded in the matrix material. Based on such technical advancement, this paper proposes an analytical method ...
Tópico(s): Structural Load-Bearing Analysis
2008 - Japan Society Mechanical Engineers | Journal of System Design and Dynamics
Zihui Xia, Feng Ju, Katsuhiko SASAKI,
A successful deployment of the stent is dependent on the good understanding of its mechanical properties. This paper presents a general RUC (repeated unit cell) approach for the analysis of balloon expandable stents with various types of closed cells. The application of the unified periodic boundary conditions on the RUC model of the stent is formulated. Numerical analysis is performed by the ABAQUS FEM package. Stents of the Palmaz-Schatz type and NIR® type with V- or S-shaped links are analyzed ...
Tópico(s): Concrete Corrosion and Durability
2007 - Elsevier BV | Finite Elements in Analysis and Design
Feng Ju, Zihui Xia, Katsuhiko SASAKI,
Finite element method (FEM) has been extensively applied in the analyses of mechanical and biomechanical properties of stents. Geometrically, a closed-cell stent is an assembly of a number of repeated unit cells and exhibits periodicity in both longitudinal and circumferential directions. The objective of this paper is to study the FEM models for the analysis of stents. To this end, three models, termed respectively as the Panel, RUC (repeated unit cell) and RUC+ (repeated unit cell with a free end) ...
Tópico(s): Elasticity and Material Modeling
2007 - Elsevier BV | Journal of the mechanical behavior of biomedical materials/Journal of mechanical behavior of biomedical materials
Tsuyoshi MAYAMA, Katsuhiko SASAKI, Haruto Ishikawa,
This paper presents a unified constitutive model for cyclic viscoplasticity and changes occurring in subsequent viscoplastic deformation due to the evolution of dislocation structures. The model considers the viscoplastic potential and a modified Ramberg–Osgood law. Stress is assumed to divide into three components: back stress (the center of the yield surface), flow stress (the radius of the yield surface), and viscous stress (overstress). The modification of the Ramberg–Osgood law is carried out ...
Tópico(s): Fatigue and fracture mechanics
2006 - Elsevier BV | International Journal of Plasticity
Ken-ichi OHGUCHI, Katsuhiko SASAKI, Masahiro Ishibashi,
Tópico(s): High Temperature Alloys and Creep
2006 - Springer Science+Business Media | Journal of Electronic Materials
Katsuhiko SASAKI, Takehiko Takahashi,
Low cycle thermal fatigue tests were conducted using an aluminum alloy AC2B-T6, which is widely used in diesel engines, especially, in cylinder heads. Specimens made of the AC2B-T6 alloy were subjected to thermal fatigue with thermo-mechanical loadings over several temperature ranges, symmetric and asymmetric strain amplitudes, and cycle periods. These test conditions are chosen considering realistic running conditions of diesel engines. A method to predict time to fatigue failure under the test ...
Tópico(s): Aluminum Alloy Microstructure Properties
2005 - Elsevier BV | International Journal of Fatigue
Tsuyoshi MAYAMA, Katsuhiko SASAKI,
This paper investigates the effects of cyclic preloading on the subsequent viscoplastic deformation. A series of experiments such as the subsequent creep, subsequent stress relaxation, and cyclic loading with strain rate changes after cyclic preloading were conducted with Type 304 stainless steel at room temperature. The cyclic proportional and non-proportional loadings were conducted as cyclic preloadings. Tension-compression loading was chosen as the cyclic proportional loading, and circular and ...
Tópico(s): Fatigue and fracture mechanics
2005 - Elsevier BV | International Journal of Plasticity
Ken-ichi OHGUCHI, Katsuhiko SASAKI, Masahiro Ishibashi, Takamichi Hoshino,
This paper applies a constitutive model proposed previously by the authors to three lead-free solder alloys of Sn/Ag, Sn/Bi and Sn/Zn. First, the material constants in the constitutive model are determined using the so-called "plasticity-creep separation method" by simple tests such as pure tensile tests. The constitutive model is incorporated into a general purpose Finite Element Method program ANSYS using the stress integration method. The material constants for the lead-free solders could be simply ...
Tópico(s): Metal Forming Simulation Techniques
2004 - Japan Society Mechanical Engineers | JSME International Journal Series A
M. Iizuka, Hiroaki Itou, Shiho Konno, Junichi Chihara, M Tobita, Hiroko Oyamada, Itaru Toyoshima, Katsuhiko SASAKI, Akiko Satô, Yasuo Horie, Shinya Watanabe,
Tube feeding is regarded as a risk factor for Clostridium difficile-associated diarrhoea. Recently, we reported that C. difficile toxin was frequently found in patients receiving an elemental diet. The present study was conducted to clarify whether elemental diets are associated with the growth of C. difficile in the gut flora.C. difficile was cultured for 72 h in various concentrations of elemental diet containing 3% thioglycollate, and the growth rate or activity of C. difficile was evaluated ...
Tópico(s): Microscopic Colitis
2004 - Wiley | Alimentary Pharmacology & Therapeutics
Katsuhiko SASAKI, Ken-ichi OHGUCHI, Hiromasa ISHIKAWA,
This study first proposes a simple constitutive model for viscoplasticity, which includes the elastic, plastic, and creep strains independently. The plastic strain is evaluated by the flow rule employing back stresses evolved with a Ziegler type of hardening rule. The creep strain is evaluated by the modified Norton’s law. The applicability of this constitutive model is evaluated with pure tensile tests, creep tests and cyclic tension-compression loading tests, to demonstrate the progress of viscoplastic ...
Tópico(s): High Temperature Alloys and Creep
1999 - ASM International | Journal of Electronic Packaging
Haruto Ishikawa, Katsuhiko SASAKI,
Plastic-deformation induced anisotropy and memorization of back stress due to pre-loading affect the current loading. These phenomena are examined with tension and/or torsion tests, using SUS 304. Considering both anisotropy, and movement and memorization of back stress, equi-plastic surfaces are predicted. This explains the dependence of current loading on pre-loading well. Simulated strain paths during radial loading after shear straining show good agreement with experiments.
Tópico(s): Mechanical stress and fatigue analysis
1998 - Elsevier BV | International Journal of Plasticity
Katsuhiko SASAKI, M. Kishida, Takamoto Itoh,
Tópico(s): Advanced Machining and Optimization Techniques
1997 - Springer Nature | Experimental Mechanics
Hiromasa ISHIKAWA, Katsuhiko SASAKI, Ken-ichi OHGUCHI,
This paper treats the prediction of fatigue life of 60Sn-40Pb solder alloy using the plastic strain work density per unit time calculated from the proposed constitutive model for cyclic viscoplasticity. At first, in order to verify the applicability of the proposed constitutive model to the deformation of 60Sn-40Pb solder alloy, a series of basic experiments, such as creep tests and cyclic tension-compression loading tests are performed at 303K, 323K, 343K. Then, the proposed constitutive model ...
Tópico(s): Fatigue and fracture mechanics
1996 - ASM International | Journal of Electronic Packaging
Michiko Ishikawa, KEIKI TANNO, Atsuko Kamo, Yoshio Takayanagi, Katsuhiko SASAKI,
The effect of morphine on tumor growth of EL-4 leukemia in C57BL/6 mice and of Sarcoma 180 carcinoma in ddY mice was studied. Local subcutaneous tumor growth was enhanced by morphine (10 mg/kg, s.c.) given daily for 10d. This effect was inhibited by preadministration of the opioid antagonist naloxone. However, naloxone alone had no significant effect on tumor growth. Morphine also enhanced tumor growth in C57BL/6 mice inoculated i.p. with P388 as well as Meth-A cell in Balb/c mice. However, incubation ...
Tópico(s): Anesthesia and Neurotoxicity Research
1993 - Pharmaceutical Society of Japan | Biological and Pharmaceutical Bulletin
Haruto Ishikawa, Katsuhiko SASAKI,
To formulate the constitutive equations for cyclic plasticity, the subsequent yield surfaces should be examined carefully. In this paper, the subsequent yield surfaces have been examined from the experiment for the initially isotropic material of SUS304 subject to cyclic loading, using a 50µm/m offset strain criterion for yielding probed at the current center of the yield surface. The experiment shows a translation, distorsion, and rotation of the subsequent yield surfaces because of the deformation- ...
Tópico(s): High-Velocity Impact and Material Behavior
1988 - American Society of Mechanical Engineers | Journal of Engineering Materials and Technology