-
Hironori TOHMYOH, Takuya IMAIZUMI, Masumi SAKA
Article type: Article
Session ID: 447
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The melting phenomena of very-thin metallic wires were considered for joining the wires. The center of thin Pt wire having the diameter of about 800 nm was locally melted by a direct current supply, and the Pt wire could be successfully cut at the predetermined point. A constant direct current was applied to the system wherein the free ends of two Pt wires were contacted each other, and the ends of the wires were successfully joined together. A parameter, which governed the melting phenomenon at the contacts of very-thin wires, was proposed.
View full abstract
-
AKANDA M. A. Salam, Hironori TOHMYOH, Masumi SAKA
Article type: Article
Session ID: 448
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this study a new testing methodology with a setup to determine the mechanical properties nanowires based on bending under lateral load is reported. In the setup a force sensor, a piezo stage and two nano-manipulators have been accommodated on a single platform. A small-span bending load using two opposite probes is applied far from the root of the wire to ensure the failure in the wire across the loading point, and the load-displacement data are recorded. For evaluating the properties from the measured load-displacement relationship, finite element (FE) analysis of the bending problem under the same loading configuration has been performed. The elastic-plastic properties of 800 nm platinum (Pt) sample, especially, Young's modulus, yield strength and hardening modulus are successfully determined by fitting the load-displacement relationship obtained in FE analysis to the experimental one.
View full abstract
-
Ryohei TOBE, Mikio MURAOKA
Article type: Article
Session ID: 449
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This study presents a novel technique of mechanical test of nanowires (NWs). A NW standing on a substrate is deflected by means of a micro-cantilever, where interactive force like van der Waals provides adhesion enough for fixing the free end of the NW. Bent shape of the NW is observed in optical microscopy and the reactive force is measured from the cantilever deflection, detected by a laser interferometer. Luminance profile of the diffraction image provides a measure of the diameter. Inverse analysis on nonlinear mechanics successfully allows an evaluation of the Young's modulus. In addition, manipulation of the cantilever gives a fracture test based on observation of bending radius at fracture. Examples for CuO NWs showed a diameter dependence of Young's modulus and strength.
View full abstract
-
Mikio MURAOKA, Ryohei TOBE
Article type: Article
Session ID: 450
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This study investigated peeling mechanics of a nanowire adhered to a substrate. A CuO nanowire standing on Cu wire surface was adhered to an aluminum-coated surface of micro-cantilever by the inter-surface force like van der Waals. The cantilever deflection was monitored by means of a laser interferometer during retractive movement of the Cu wire. Sliding of the nanowire was observed before the peeling. This allowed the measurement of the friction force. Energy balance theory was introduced for the peeling mechanics. The theoretical formula successfully predicted the adhesion energy 1 nJ/m from the measured adhesion force. The value was validated form the comparison with that predicted theoretically for van der Waals interaction.
View full abstract
-
Takahiro Ito, Junpei Doi, Akira Hibi, Yutaka Kukita
Article type: Article
Session ID: 501
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The behavior of a moving contact line on structured surface is analyzed by molecular dynamics. The analyses were made by using a Couette flow geometry where two immiscible fluids are sheared between two parallel plates, one of which is characterized by step-structured surface with a depth of one or more times of the wall lattice constant a_0, set to be almost equal to the average distance between liquid atoms. The contact lines strongly tend to be captured at the edge of the steps and the minimum contact angle is dependent on the depth of the steps. When the depth is identical to as the contact angle decreases by several tens degrees from that for the plane surface before the contact line leaves the edge of the steps. When the depth is twice a_0, the contact lines stay at the step edge until the contact angle decreases almost zero.
View full abstract
-
Kiyoshi TAKEUCHI, Masahiko SHIBAHARA
Article type: Article
Session ID: 502
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The classical molecular dynamics simulation was conducted in order to clarify the effects of the surface structural clearances in nanometer scale on thermal resistance at a liquid-solid interface as well as static and dynamic behaviours of fluid molecules in the vicinity of the surface. A liquid molecular region confined between the solid walls, of which the interparticle potential was Lennard-Jones type or SPC/E type, was employed as a calculation system. The thermal resistance between the liquid molecular region and the solid walls with nanostructures was calculated by the heat flux and the temperature jump obtained in the molecular dynamics simulations. With changing the surface structural clearances and the potential energy functions the thermal resistance between the liquid molecular region and the solid walls with nanostructures once decreased and became the minimum value when the structural clearances were changed from 0 to several nm regardless of potential functions between liquid molecules employed in the present study.
View full abstract
-
Takao TOSHIMA, Masahiko SHIBAHARA
Article type: Article
Session ID: 503
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In order to elucidate the mechanism of low thermal conductivity caused by nanostructures and nano-stractural clearances, we calculated thermal conductivity, a phonon dispersion relationship. and density of states in model thin film depending on nanostructures and nano-structual clearances by the classical molecular dynamics simulation (MD).We can observe some change of the group velocity of partial phonon in the phonon dispersion relations of the longitudinal wave as well as the reduction of thermal conductivity when the nano structural clearance was relatively small.
View full abstract
-
Gyoko NAGAYAMA, Takaharu TSURUTA
Article type: Article
Session ID: 504
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Molecular dynamic (MD) simulations have been carried out to study the effects of the nanostructures on the interfacial heat and mass transfer at the solid-liquid interface. The liquid particles near saturation are confined in two solid surfaces with nanostructures in a shape of molecular-scale unevenness. It is found that the interfacial thermal resistance decreases but the hydrodynamic resistance increases at the nanostructured surfaces in comparing with the flat surface. The heat flux across the nanostructured solid-liquid interface increases corresponding to the increasing surface area and thus, effective heat transfer enhancement has been achieved by the effects of nanostructures.
View full abstract
-
Chia Yuan Tan, Daichi Torii, Gota Kikugawa, Taku Ohara
Article type: Article
Session ID: 505
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Molecular dynamics simulations have been performed on ultra-thin liquid film which is sheared between two solid surfaces to clarify the mechanisms and characteristics of momentum and thermal energy transfer at solid-liquid interface. Four types of crystal plane of FCC lattice were examined for the surface of platinum solid wall and four types of n-alkane were employed as liquid. It was found that transfer characteristics of thermal energy and momentum at the solid-liquid interfaces were significantly influenced by the types of crystal plane of the solid surface and the length of the n-alkanes.
View full abstract
-
Take Nakano, Gota Kikugawa, Taku Ohara
Article type: Article
Session ID: 506
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Nonequilibrium molecular dynamics simulations are performed on lipid bilayer membranes with ambient water under shear flow along the bilayer plane to investigate conformational change of lipid molecules. In the case of a shear rate of 12.9ns^<-1>, the velocity gradient in the lipid bilayer region is extremely small, while that in water layer is much larger. In spite of the small velocity gradient, configurations and conformations of the lipid membrane are clearly changed as compared to those in an equilibrium state. The lipid bilayer is distorted and lipid molecules are tilted by approximately 30 degrees from the normal of the bilayer plane toward the flow direction, and randomness of hydrocarbon chains of lipid molecules was increased.
View full abstract
-
Gota Kikugawa, Taku Ohara, Toru Kawaguchi, Eiichi Torigoe, Yasumasa Ha ...
Article type: Article
Session ID: 507
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, we perform molecular dynamics simulations of self-assembled monolayer (SAM) and solvent interfaces in order to elucidate the microscopic mechanisms of interfacial heat transfer at the SAM interfaces. Archetypal SAM systems, i.e., n-alkanethiol chemically adsorbed on Au (111), and toluene solvent are employed in our simulations. By using nonequilibrium molecular dynamics technique, a temperature gradient is imposed perpendicular to the interface, and interfacial heat transfer characteristics are analyzed. In addition to the SAM systems, a bare solid substrate and solvent system is examined to compare thermal boundary resistances at the SAM-modified interface and non-modified one. As a result, we find a significant decrease of the thermal boundary resistance at the SAM-toluene interface as compared to that of the bare Au interface. In order to explain this effect, we focus on the adsorption structure of toluene in the vicinity of the interface.
View full abstract
-
Daigo ITO, Takashi TOKUMASU
Article type: Article
Session ID: 508
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Dissociative adsorption phenomena of hydrogen molecule on platinum surface was simulated by the Molecular Dynamics Method. The Embedded Atom Method (EAM) was used as an interaction potential between an H_2 molecule and a Pt surface in order to reproduce the dissociation barrier which the molecule has to pass over to dissociate on the surface. The functions of the EAM were adjusted so that they can describe the orders of dissociation barriers at some dissociation sites on a Pt(111) surface calculated by the Density functional theory (DFT). Many cases of collision of an H_2 molecule with a Pt(111) surface were simulated and dissociation probability was obtained. Using the results, the dependence of dissociation probability on dissociation barrier at some dissociation sites on a Pt(111) surface was analyzed.
View full abstract
-
Ikumi ONISHI, Kentaro DOI, Satoyuki KAWANO
Article type: Article
Session ID: 509
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Carbon materials attract much attention because of their possibility as effective hydrogen storages. In a hydrogen adsorption process, two steps of chemical reactions are expected; (i) dissociation of hydrogen molecules and (ii) adsorption of hydrogen atoms on carbon atoms. In this work, the hydrogen adsorbing mechanism on graphene surfaces has been analyzed using a combined method of molecular dynamics and first-principles calculations. As a result of those calculations, defects and distortions in graphene layers cause their peculiar electronic structures and generate a preferable conformation for hydrogen adsorption. It is suggested that first-principles calculations are available in order to treat chemical reaction systems because they actually represent charge transfers between each atom. Furthermore, atomic forces calculated using first-principles methods can be coupled to molecular dynamics simulations and the results of those simulations explains experimental observations. Consequently, activation energies for the hydrogen storage and discharge have been estimated 2.06 eV and 0.64 eV, respectively. This result suggests carbon materials such as graphene are preferable for a hydrogen storage material.
View full abstract
-
Kentaro DOI, Satoyuki KAWANO
Article type: Article
Session ID: 510
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We are interested in multi-physics observed in biomolecules such as deoxyribonucleic acids (DNAs). Phenomena in biomolecules should be understood in multi-scale. The role of charge transfer in DNA base molecules is one of the hottest topics. In this study, propagation of electron wave functions in DNA base molecules has been investigated. The calculations have been examined for the highest occupied molecular orbital (HOMO) on an adenine molecule and the lowest unoccupied molecular orbital (LUMO) on a guanine molecule. Wave functions in each initial state propagate along the external electric field and diffuse from the base molecules. Hopping propagations via hydrogen bonds between base molecules have not been induced although diffusions between base pairs along the DNA axis have been observed. A numerical method for wavepacket dynamics is suggested and that is efficient for long time dynamics simulations which require conservation of quantities.
View full abstract
-
Toru UCHIDA, Yu MATSUDA, Yoshiki SAKAZAKI, Suguru SUZUKI, Hideo MORI, ...
Article type: Article
Session ID: 511
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
To analyze a micro/nano scale flow, we need to adopt a measurement technique that treats the flow as a molecular flow, because the flow cannot be treated as continuum. The pressure sensitive molecular film (PSMF) technique employs interaction between molecules, hence it is suitable for pressure measurement in the flow. We developed PSMF that is effective in the low pressure range. Typically, effective pressure range of PSMF depends mainly on the kind of luminophores. In this study, we adopt new luminophores in order to develop a new PSMF for near-atmospheric pressure range. Furthermore, because luminophores of PSMF are easily deteriorated by light, it is very important to consider photo-deterioration in pressure measurement by PSMF. In this study, we also analyzed photo-deterioration of PSMF to clarify basic photo-deterioration feature of PSMF.
View full abstract
-
Hiroki YONEMOTO, Ikuya KINEFUCHI, Shu TAKAGI, Yoichiro MATSUMOTO
Article type: Article
Session ID: 512
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We studied the scattering process of He molecules on a single wall carbon nanotube (SWNT) using molecular dynamics simulations and evaluated the collisional energy transfer between SWNT and He molecule. The decrease of the incident angle enhances the energy exchange between SWNT and He molecule because of the surface structure which deforms easily in radial direction. In contrast, the deflection angle does not substantially affect the amount of the energy transfer. In order to analyze the effect of the anisotropic surface structure on the scattering process in detail, we decomposed the amount of the energy transfer into the normal and the tangential component and found that the temperature dependence of the post-collisional energy is mainly due to the change of the normal component while the tangential one is almost independent of the temperature.
View full abstract
-
Masashi YAMAGUCHI, Shigeru YONEMURA, Takanori TAKENO, Hiroyuki MIKI, T ...
Article type: Article
Session ID: 513
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Diamond-coating is promising for sliding surface because it produces very low friction. Nakamori et al. found experimentally that the friction between a partly polished diamond-coated surface and a metal surface was drastically reduced to zero as relative speed was increased. In their experiment, sliding became noiseless. This indicates that the substrate with diamond coating takes off the counter surface and the sliding mechanism is gas film lubrication. In the present work, we investigate the floating mechanism and the effect of micro gas flow on friction properties by performing numerical simulations. Since the surface roughness of the partly polished diamond-coated substrates is from 0.28 gm to 0.57 gm, Knudsen number Kn is larger than 0.1. Therefore, a flow between two sliding surfaces cannot be treated as a continuum. To simulate this flow, we use the direct simulation Monte Carlo (DSMC) method.
View full abstract
-
Hiroki YAMAGUCHI, Tsuneo HANAWA, Hideo MORI, Tomohide NIIMI
Article type: Article
Session ID: 514
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Gas-surface interaction is important in high Knudsen number flows, such as rarefied gas flows or micro/nano scale flows. Bulk averaged properties such as thermal and momentum accommodation coefficients are convenient for a simple analysis. On the other hand, the molecular beam scattering experiment is a very effective way to obtain valuable detailed information. It is important to clarify the relation between these results; therefore we investigated it by the Molecular Dynamics simulations. The molecular beam scattering experiment is reproduced and a scattering angular distribution is validated. Energy accommodation coefficients are obtained and validated for three conditions of surface temperature. The relation is analyzed by decomposing in normal and tangential values.
View full abstract
-
Satoshi NAKADA, Takashi MATSUZAKI, Takayoshi INOUE, Yuji SUZUKI
Article type: Article
Session ID: 515
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Flow characteristics of gases in flow channels of 3-4 nm in diameter were studied experimentally. As the nanoscale channels, silica-surfactant nanocomposite membranes having rather uniform diameters and straight channels were used. The flow characteristics were investigated by changing gas temperature from 20 to 60 ℃ and kinds of gases, N_2, Ar, He, CO_2 and R-134a (hydrofluorocarbon). As the results, the possibility is presented that the flow in the nanoscale channels is a mixture of rarefied gas flow and surface diffusion flow.
View full abstract
-
Masaya Hayashida, Yu Matsuda, Dai Naito, Hideo Mori, Tomohide Niimi
Article type: Article
Session ID: 516
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Non-uniform pressure distribution on shrouded co-rotating disks at high speed causes disk flutter. For stable rotation of disks at high speed, it is necessary to analyze pressure distribution on the disk surfaces and understand the mechanism of the disk flutter. To clarify the behavior of the flow around high-speed co-rotating disks, we have measured pressure distribution of disk surfaces by means of pressure sensitive paint. As a result, it is clarified that the pressure difference between the outer part and the inner part of the middle disk of the triple co-rotating disks is larger than that of the top disk, and the average pressure on the middle disk is lower than that of the top disk.
View full abstract
-
Akiomi USHIDA, Tomiichi HASEGAWA, Takatsune NARUMI, Shota KUDO
Article type: Article
Session ID: 517
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We measured jet thrust and pressure drop in water flowing through micro-orifices. It was found that the measured jet thrust and pressure drop agreed with the prediction by Navir-Stokes equation for the orifices more than 100micron meter diameter. However, they were lower than the prediction for the orifices less than 50micron meter diameter. As a results, possibility of normal stress in elongatinal flow has been strongly suggested.
View full abstract
-
Masahiro Karasawa, Tomiichi Hasegawa, Takatsune Narumi
Article type: Article
Session ID: 518
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We observed liquids dripping out of an aperture at low Reynolds number using CCD camera, measured the mass of a drop and the velocity of falling drops, and estimated dynamic surface tensions. Reynolds number ranged from 1 to 200. The solutions tested were PEG solutions in water. A modeling for large molecules was presented for predicting the normalized dynamic surface tension of polymer solutions. It was confirmed that the expression obtained by this model approximately agrees with the experimental values.
View full abstract
-
Hidemasa TAKANA, HongYang LI, Kazuhiro OGAWA, Tsunemoto KURIYAGAWA, Hi ...
Article type: Article
Session ID: 519
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A real-time and realistic computation on the entire cold gas dynamic spray process has been carried out by the integrated model of flow considering shock wave, splat formation, and coating formation. The in-flight behavior of nano/micro particle in the supersonic jet impinging on the substrate with a cavity, and also the interaction between a particle and shockwave has been made clear from this study. By clarifying the effect of cavity shapes on a coating formation inside the cavity, optimum cavity shape was proposed for cavity filling process. Then, the fundamental data has been provided for the advanced application of a high performance cold gas dynamic spray process to a dental treatment or structural repair.
View full abstract
-
Yasunori NISHIMURA, Hiroshi YAMADA
Article type: Article
Session ID: 520
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We formulated a mass-spring system model of the apical membrane of the cell to describe the deformation of a vascular endothelial cell under substrate stretching. The motion of each mass was governed by the equation of motion with an artificial damping effect, and the force was derived from the energy which was formulated by Wada and Kobayashi (2003) for a red cell. The energy was the sum of an elastic energy of springs in tension/compression, that of triangular elements in bending, constraints of the cellular volume and surface area. The cellular geometry was constructed from a set of images obtained by confocal scanning laser microscopy. The numerical simulation was performed under the condition of pure uniaxial stretching of a substrate by 10%, and was compared with results from a finite element analysis of a hyperelastic whole cell model. A comparison suggested a necessity of an evaluation of cytoskeletons.
View full abstract
-
Shinji NOBUHARA, Shunsuke TAKASAKI, Hiroshi YAMADA, Shogo MIYATA
Article type: Article
Session ID: 521
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We observed morphological changes in human skin fibroblasts, which were incubated for 6 hours, by a confocal scanning laser microscope and a light microscope under various conditions of nutrients and temperature. The cells were embedded in a collagen gel with 0.3-mm thickness. The condition of nutrition was given by using a mixture of Dulbecco's modified eagle medium and Ham's F-12 as a control and Dulbecco's phosphate buffered saline as a nutrient-free environment. The condition of temperature was given as 37℃ as a control and 25℃ which was about 10℃ lower than the control. By combining these conditions, we investigated the effect of lowering the temperature in the nutrient-free condition. The nutrient-free environment enhanced cells near the gel surface to become spherical at 37℃, while lowering the temperature to 25℃ prevented this response but did not protect cells from a reduction of their density in the gel.
View full abstract
-
Atushi Nakano, Nobutaka Inoue, Tatsuya Sawamura
Article type: Article
Session ID: 522
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Hypertension is a powerful independent risk factor for atherosclerotic cardiovascular diseases; however, the precise molecular mechanisms whereby hypertension promotes atherosclerotic formation remain to be determined. The interaction of oxidized low density lipoprotein (LDL) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) plays a critical role in atherogenesis. To investigate their specific roles in acceleration of atherogenesis by hypertension, here, we employed stroke prone spontaneously hypertensive rats (SHR-SP), models of human essential hypertension, rapidly developed arterial lipid deposition in mesenteric arteries when fed on high fat diet and salt loading. These vascular lipid deposition lesions share similar characteristics of the initial lesions of atherosclerosis. The enhanced LOX-1 expression in SHR-SP was closely associated with deposited lipids, oxidized LDL, and generation of reactive oxygen species. Anti-LOX-1 neutralizing antibody dramatically suppressed lipid deposition in vivo in SHR-SP. Vitamin E decreased plasma oxidized LDL, which suppressed the lipid deposition as well. Furthermore, anti-LOX-1 antibody suppressed the increase in vascular permeability and uptake of oxidized LDL in SHR-SP. Thus, the enhanced expression and activation of LOX-1 leading to an increase in vascular permeability and oxidative stress plays an essential role in vascular lipid deposition under hypertensive states.
View full abstract
-
Kei SUZUKI, Toshihiko SHIRAISHI, Shin MORISHITA, Hiroshi KANNO
Article type: Article
Session ID: 523
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Neural stem cells have been studied to promote neurogenesis in regenerative therapy. It is important to investigate not only chemical factors but also mechanical factors such as hydrostatic pressure in. In this study, we investigated effects of mechanical vibration on cell proliferation and differentiation by in-vitro cell culture. It is shown that mechanical vibration promotes the ploliferation and its cause is likely the suppression of apoptosis, and that the mechanical vibration at the experimental condition does not affect the differentiation of neural stem cells to nerve cells or glia cells.
View full abstract
-
Yuta TAKAGI, Toshihiko SHIRAISHI, Shin MORISHITA, Ryohei TAKEUCHI, Tom ...
Article type: Article
Session ID: 524
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The healing of articular cartilage that possesses little capacity for self-repair after having been damaged is still a clinical problem. This paper describes the effects of vibration stimulation on chondrocytes in three-dimensional culture that imitates actual articular cartilage in relation to the production of regenerative cartilage tissue, using collagen gel and artificial skin as a carrier. The obtained results are the mechanical vibration advances the matrix production and proliferation of chondrocytes.
View full abstract
-
Hiroyuki HAYASHI, Kenichi YAMASAKI, Douhiko TERADA, Hideo KONDO, Masan ...
Article type: Article
Session ID: 525
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The purpose of this study is to engineer skeletal muscle tissue from myoblasts for development of bio-actuator. We evaluated the contractile force of the complex tissue made of elastase treated tissue and collagen gel as scaffold for engineered skeletal muscle. The C2C12 cells were seeded in collagen gel and cultured at 37℃ under 5% CO_2. After 10 days in culture, tissue-engineered muscle contracted with electrical pulse stimuli and, the isometric contractile force was 900 μN at 1 Hz. Hematoxylin-eosin staining showed that myoblasts remained inside the collagen gel and differented to the myotube.
View full abstract
-
Hiroshi MIYAZAKI
Article type: Article
Session ID: 526
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Local stiffness of cell nuclei isolated from vascular smooth muscle cells (VSMCs) and fibroblasts (FBs) were determined using an atomic force microscope (AFM). Nuclei were chemically isolated and attached to a cover glass in Hanks' balanced salt solution of room temperature. Then, the surface of a nucleus was observed using AFM, and force curves were obtained from the central region (8×8 μm) of the nucleus at the interval of 0.5 μm. From force-indentation curves, the distribution of local stiffness was determined in the central portion (4×4 μm) of the measurement area. Initial stiffness of the nuclei obtained from VSMCs and FBs were 0.43 nN/μm and 0.36 nN/μm, respectively; there was a tendency that the nucleus of VSMCs was stiffer than that of FBs, but the difference was not statistically significant. These results suggest that the difference in cell types does not affect much to the local surface mechanical properties of cell nucleus.
View full abstract
-
Kazuaki NAGAYAMA, Yuki KIMURA, Takeo MATSUMOTO
Article type: Article
Session ID: 527
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
It has been reported that the stress fibers (SFs) of cells on elastic substrate aligned at a particular angle so as to minimize their strain magnitude caused by cyclic deformation of the substrate. However, little is known about the mechanism of their alignment. In this study, we investigated the effects of cyclic stretch waveform and intercellular junctions on the SF alignment in MC3T3-E1 osteoblast-like cells. The cells were cultured on silicone membranes under a sparse (15 cells/mm^2) or dense (300 cells/mm^2) condition, and subjected to cyclic uniaxial stretch having either one of the following wave forms with an amplitude of 8%: triangular; trapezoid, bottom hold, or peak hold for 24 h. Alignment of their SFs were then analyzed with a two-dimensional Fourier transformation analysis. In the sparse condition, no orientation was observed for the triangular and the peak hold waveforms, while SFs aligned mostly in the direction in which normal strain of substrate becomes zero (〜54°) with other waveforms, especially with the trapezoid waveform which had a hold time both at the maximum strain and the zero-strain state. Intracellular SFs generate a prestress, and they depolymerize with release of their prestress. They are also viscoelastic. Thus our results indicate that depolymerization and reorientation of SFs were significantly accelerated with the release of their prestress caused by the stress relaxation of SFs during the hold times in the trapezoid waveform. In the dense condition, in which cells have intercellular junctions, SFs aligned in perpendicular to and/or parallel to the stretch direction with the triangle waveform and in perpendicular to the stretch direction with other waveforms, as if the cells avoided shear deformation causing breakdown of cell-cell junctions. These results indicate that time history of stress applied to the SFs as well as intercellular junctions may have profound effects on cell alignment in MC3-3-E1 cells.
View full abstract
-
Yusuke MITSUOKA, Takeshi TOUJO, Akira TSUKAMOTO, Takayuki AKIMOTO, Kat ...
Article type: Article
Session ID: 528
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
It is well known that stress fibers of endothelial cells orient in a direction perpendicular to the stretch axis when subjected to cyclic stretch. However, little is known about the mechanism of this response. The main purpose of this study is to clarify the process of stress fiber's orientation and its relation to the focal adhesion. We grew HUVECs on deformable silicone membrane and subjected them to 22.5% uni-axial cyclic stretch for 30 to 140 minutes. Images of GFP-actin and Dsred-zyxin were taken every 30 seconds or 1 minutes. Though stress fiber's oriented in diverse ways, we were able to classify them into three types, rotation type, appear/disappear type, and recombination type. High resolution time-lapse imaging revealed the dynamic process of stress fiber orientation.
View full abstract
-
Yunfeng YANG, Kazuaki NAGAYAMA, Takeo MATSUMOTO
Article type: Article
Session ID: 529
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Stress fibers (SFs) play essential roles in various cellular functions such as cell movement, shape maintenance and cell division. In addition, changes in the mechanical environment induce reorganization of the SFs. Recently, we noticed that the SF networks reappeared following their temporal disruption with cytochalasin D looked similar to those before disruption in rat aortic smooth muscle cells (RASMs). This indicates that the cells may have a memory of SF orientation. The aim of this study was to clarify the mechanism of the memory particularly focusing on the effects of microtubules (MTs) and focal adhesions (FAs) during the reorganization process of SFs. Firstly, we preconditioned the cells with cyclic stretch to make their SFs align in a uniform direction. After cyclic stretching, we depolymerized SFs completely with cytochalasin D for 3 h, and let them repolymerize in the drug free medium for 3 h. To know the effects of MTs during the SF repolymerization, we depolymerized MTs with colchicine. FAs were observed with a surface reflective interference contrast microscopy. In the presence of MTs, repolymerized SFs appeared in random orientation with newly formed FM, while FM were not destroyed and the alignment of SFs was conserved in the absence of MTs. The conservation of FAs might serve as a memory of SF alignment.
View full abstract
-
Satoshi KAMADA, Akihiro SHIMONO, Kazuyuki MINAMI, Katsuya SATO
Article type: Article
Session ID: 530
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this study, we have developed a novel cell stretching micro device to observe cellular response to mechanical stimuli with high spatial and temporal resolution. In conventional cell stretching device, rigid displacement of cell body during stretching operation is not negligible. And this rigid displacement makes it difficult to observe instant initial cellular response to stretching. The novel micro device is fabricated by applying MEMS technique, and consists of a transparent elastic micro chamber and a micro linkage mechanism. The micro chamber and the linkage mechanism are fabricated by micro molding and multiple exposure technique of photoresist, respectively. We demonstrated availability of fabrication process, and evaluated performance of the micro device. When applying a stretch to chamber, rigid displacement was well suppressed. This result indicated a potential of this device to observe instant initial cellular response to stretching mechanical stimuli.
View full abstract
-
Kaichirou KAWANAKA, Yasuyomo UETSUJI, Eiji NAKAMACHI
Article type: Article
Session ID: 531
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The purpose of this research is to develop a compact and wearable HMS (Health Monitoring System) device which automatically 1) puncturing a blood vessel, 2) extracting and delivering human blood and 3) measuring blood glucose. In this study, a syringe reciprocal type blood extraction pump is employed, which has a painless micro-needle with about 100μm inner diameter. The developed suction device consists of disposable syringe part and continuously-used base part. As a result of performance test , the developed device was able to get above 90% of volumetric efficiency when the driving speed of the piston is set to 1.0mm/s.The blood sugar level is measured successfully by implement of the glucose enzyme sensor.
View full abstract
-
Keita YOSHIDA, Katsuko FURUKAWA, Takashi USHIDA
Article type: Article
Session ID: 532
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Stem cells play important role in tissue engineering. However, stem cells are very rare and difficult to identify. Therefore, an efficient and accurate cell separation method is needed. In this study, we developed a cell sorting system using a cone-plate rheometer for extraction of rare cells from cell mixture. The separation principle of this system is based on specific adhesion by the antigen-antibody interaction between cells and antibody-coated plate. We evaluated the performance of this cell sorting system using two different cells (HL-60, HUVEC) and antibodies (CD15, CD31).
View full abstract
-
Shukei SUGITA, Naoya SAKAMOTO, Toshiro OHASHI, Masaaki SATO
Article type: Article
Session ID: 533
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Microtubules (MTs) gliding on the kinesin-coated surface in vitro have a good feasibility for development of micro-scale transport systems. The key requirements in the development of the system include an image analysis to detect and recognize gliding MTs. In this study, we present an algorithm for detecting the position of the leading tips of gliding MTs. The algorithm operates on binarized fluorescent images of MTs and extracts the tips of MTs with a kernel. For verification, the algorithm was applied to a sample segment, and the distance between extracted coordinates with the algorithm and given coordinates were referred to an error. As a result, the algorithm caused the error, in which the measurement length was shorter than the actual length by only a half of the sample width. By applying the algorithm to the gliding MTs, the tips were well extracted following the trajectories of gliding MTs. The present algorithm for the tip-tracking may be useful for constructing nano-scale transport systems.
View full abstract
-
Yuki KIHIRA, Taiji ADACHI, Junko SUNAGA, Masaki HOJO
Article type: Article
Session ID: 534
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
"Bottom up" is another possible approach to nanotechnology as well as the conventional "top down" approach. This approach requires special nano-structural elements with a size of nanometers and a property of self-assembly to an elaborate product. One strong candidate for the materials of such elements is single-stranded DNA (ssDNA), because this material possesses strict base-pair specificity and selectivity. In the course of fabrication of DNA nanostructures, circular single-stranded DNA (cssDNA) is often used as the intermediate form. The cssDNA is constructed by the simple Dolinnaya's method, which uses two of ssDNA, a body of the ring (Precursor) and a mediator that brings the DNA ends together (Template). Precursor was certainly circularized by Template and a ligating enzyme, and formed the monomeric cssDNA in a topoisomeric fashion, but multimeric cssDNA is also produced which was constructed from many precursors. The amount of monomeric cssDNA and multimeric cssDNA were altered by the length and sequence of the precursor and template.
View full abstract
-
Shun KUMANO, Koji IIDA, Michio MURAKOSHI, Kouhei TSUMOTO, Katsuhisa IK ...
Article type: Article
Session ID: 535
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Prestin is believed to be the motor protein of outer hair cells. In this study, characterization of prestin was performed by mutational analysis focusing on the unique amino acids in prestin. Five prestin mutants, namely, M1221, C192A, M225Q, C415A and T428L, were engineered to be separately expressed in HEK293 cells. M225Q exhibited 1.7 times greater nonlinear capacitance (NLC), which reflects the charge transfer of prestin in the plasma membrane, than that of wild-type prestin (WT), although other mutants showed NLC similar to that of WT, indicating that M122, C192, C415 and T428 are not involved in the charge transfer of prestin. On the other hand, the amount of M225Q molecules in the plasma membrane was 1.2 times greater than that of WT molecules. The increase in the amount of prestin molecules by the mutation in M225 probably indicates that prestin became more stable, but such increase does not correspond to the increase of NLC. Hence, the mutation in M225 was considered to make prestin more stable, leading to an increase in the ratio of active prestin molecules to the total amount of prestin molecules in the plasma membrane.
View full abstract
-
Takayuki MURO, Takeshi SHIGEOKA, Takeshi NINOMIYA, Norihisa MIKI
Article type: Article
Session ID: 536
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Detection of line-of-sight (LOS) has a variety of applications, such as communication tools for elderly or disabled people, assisting drivers, and effective location of traffic signs. To realize such promising applications, the LOS detecting system that does not restrict users' activities and is free from mental stress from the equipment is strongly demanded. In this paper, we propose a novel wearable LOS detection system that affects the users as little as possible both physically and mentally using dye-sensitized photovoltaic devices. The photovoltaic devices are transparent and generate voltage according to the incident light intensity. Arraying the devices on wearable eyeglasses, this system detects the difference in the reflection light from the pupil and the white of the eye and thus, the position of the pupil. We fabricated and characterized the photovoltaic device and demonstrated the feasibility of detecting the location of the pupil.
View full abstract
-
Yoshitaka SUZUKI, Yoshihiro HASEGAWA, Mitsuhiro SHIKIDA, Kazuo SATO
Article type: Article
Session ID: 537
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We previously proposed the novel type of the fabric tactile sensor produced by weaving the artificial hollow fibers. We this time constructed the theoretical fiber deformation model in the fabric tactile sensor. We at first conducted the deformation model of the single and crossed hollow fibers by applying the material mechanics, and also constructed the model showing how the contact area (sensor output) changes with the changes of the applied load or the fiber deformation. We then verified the conducted mode by the experiments, in which we used five different sized hollow fibers. The conducted fiber deformation model adequately agreed with the experimental results. The hollow fiber linearly deformed with the increase of the applied loads in the both conditions, and the spring constant linearly depended on the third power of the ratio between the thickness and the radius. We finally developed the glove-type of the tactile sensor, and experimentally evaluated its performance.
View full abstract
-
Takeshi NINOMIYA, Kazuki OSAWA, Yoshiyuki OKAYAMA, Norihisa MIKI
Article type: Article
Session ID: 538
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Virtual reality is becoming more and more important as an intuitive information transmission technology. Particularly tactile display is necessary for more advanced virtual reality. Previous tactile displays are divided into two types. One can display feelings of displacement like "rough" and "rugged" by generating displacement, the other can create illusions of texture like "smooth" and "textured" by generating vibration. However, it is problematic to realize two types at once because of the problems of drive mechanism and so on. In this research, we develop displacement amplification mechanism, which can be easily downsized and arrayed, by using MEMS technology. Displacement amplification mechanism is made up of large displacement PDMS and two chambers. Each chamber has different cross-section which can amplify displacement PDMS. Then, displacement amplification mechanism is driven by piezo actuator, and we aim to generate more real tactile feelings combining enough displacement and vibration.
View full abstract
-
[in Japanese], [in Japanese], [in Japanese]
Article type: Article
Session ID: 539
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper discusses a development in developing a fingertip tactile sensor emulating the major features of human fingertip. The proposed fingertip tactile sensor has epidermal ridges and distributed sensor elements, and could be used for roughness, stiffness, also normal and shear force, as well as torsional force detection. Experimental results suggest the proposed sensor has the capability to detect the contact state and the force information quantitatively.
View full abstract
-
Tetsuo KAN, Naoko TSUJIUCHI, Eiji IWASE, Kiyoshi MATSUMOTO, Isao SHIMO ...
Article type: Article
Session ID: 540
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We have developed a Si microfabrication based SPR (Surface Plasmon Resonance) sensor chip equipped with Si prisms and an optical grating for sensor miniaturization. The Si prism structure was used to introduce the Near-Infrared light (λ = 1550 nm) to the sensing surface and generating the evanescent light there. Smooth prism slope was fabricated by utilizing (111) planes on the (100) plane of single crystalline Si wafer by anisotropic etching, giving small 200-μm prism array with 54.74° slope angle. We also used the optical grating with about 400-μm-pitch to manipulate an SPR dip position so as to increase the design freedom of the optical path within the sensor. SPR measurements with several specimens confirmed that the combination of Si prisms and the optical grating successfully worked to excite Surface Plasmon so that the sensor's validity as a refractive index sensor was also confirmed. Since this sensor is compatible with a Si microfabrication technology, further integration of optical parts, fluidic components and miniaturization of SPR sensor becomes possible, which is necessary for the application of an SPR sensor toward an environmental sensor.
View full abstract
-
Satoshi KONISHI, Toshiaki HORIE
Article type: Article
Session ID: 541
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper presents a stepwise locomotion of a micro robot using a shear displacement of a deformable object by a pneumatic sucker. We are interested in a locomotion function of a micro robot for medical application. A medical micro robot introduced into an abdominal cavity has been studied as extension of endoscopic technology. Micro robot with locomotion function can crawl in the body for medical inspection and operate without a wire-driven motion control for the endoscopy. Proposed locomotion mechanism employs suckers in order to provide a shear displacement as well as a stable contact against the object. The proposed stepwise locomotion mechanism does not require an additional stretching actuator for inchworm motion. This paper describes design, implementation, characterization, and demonstration of the micro robot based on the proposed locomotion principle.
View full abstract
-
Satoshi SAWANO, Yoshimasa KURUMI, Toru TANI, Satoshi KONISHI
Article type: Article
Session ID: 542
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper presents a retractor as one of micro surgical tools, which was realized by applying flexible micro actuator. The refractor holds the abdominal organ to the side during the entire operation to keep the sight and operational space in endoscopic surgery. The retractor is actuated by PBA (Pneumatic Balloon Actuator), which is featured its small, soft and safe characteristics. PBA is fabricated through the simple PDMS (polydimethylsiloxane) molding process and pneumatically driven. That is to say, it is possible to hold the organ to the side safely. We researched characteristics of retractor, and verified removal of abdominal organ from the experiment on a living rabbit.
View full abstract
-
Kenji SUZUKI, Hiroyuki KOIKE, Hideaki TAKANOBU, Hirofumi MIURA
Article type: Article
Session ID: 543
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes a biomimetic water strider robot with microfabricated hydrophobic legs. Various kinds of supporting legs with hydrophobic microstructures on their surfaces were developed utilizing MEMS (microelectromechanical systems) techniques. The lift and pull-off forces of these legs were investigated experimentally and theoretically. The experimental results were in good agreement with the calculations. Furthermore, a water strider robot with twelve microfabricated legs driven by a vibration motor was developed. The robot successfully moved on a water surface and also made left/right turns by exploiting differences in the resonant frequencies of the legs.
View full abstract
-
Dzung Viet Dao, Phuc Hong Pham, Susumu Sugiyama
Article type: Article
Session ID: 544
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper presents a novel micro transportation system (MTS), which can drive micro containers in both straight and curved paths, based on electrostatic and ratchet mechanism. The micro container, which has driving-wings and anti-reverse-wings attached to the central 'backbone', is driven by electrostatic actuator through the ratchet racks in perpendicular direction. The container with the length and width of 450μm and 250μm, respectively, moves like a water strider with desirable velocity up to 200μm/sec in the straight and curved paths. In order to create the smart and flexible MTS, the elemental modules, e.g. straight, turning and separation modules with the same size (6mm×6mm) have been developed. Therefore, different configurations of the MTS can be created flexibly by assembling the elemental modules.
View full abstract
-
Article type: Appendix
Pages
App3-
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
