-
Norikazu ISHIMATSU, Masaaki TAMAGAWA
Article type: Article
Session ID: 635
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
All the region of circulatory system can not be analyzed using computational fluid dynamics (CFD), because the structure is so complicated and the analysis region is restricted by computer memory. In order to analyze the flows, it is necessary to simplify and investigate the complicated network structure of vascular system quantitatively. We showed quantification of complicated structure using fractal dimension in our previous studies. This paper describes the relation between the flow field and the fractal dimension, and the computation scheme of volume flow distribution using box-counting method. One-dimensional model of cerebral vessel with considering tree structure was established.
View full abstract
-
Hiroaki KANEDA, Masaaki TAMAGAWA
Article type: Article
Session ID: 636
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes the prediction of index of thrombus formation in shear blood flow by computational fluid dynamics (CFD) with Lattice Boltzmann Method (LBM), applying to backward facing flow, which is simple model of turbulent shear stress in the high speed rotary blood pumps and complicated geometry of medical fluid machines. Assume that blood is multiphase fluid, blood plasma and red blood cell. From the computational data of multiphase fluid of backward facing flow, the thrombus formation (thickness) is estimated.
View full abstract
-
Kenichi FUNAMOTO, Toshiyuki HAYASE, Yoshifumi SAIJO, Tomoyuki YAMBE
Article type: Article
Session ID: 637
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Development and progress of circulatory diseases are closely related to the hemodynamics in the blood vessel. However, detailed and accurate information of blood flow field has yet to be obtained due to the limitations both in measurement and numerical simulation. Hence, we have proposed the Ultrasonic-Measurement-Integrated (UMI) simulation. In this method, feedback signals derived from the difference between measured and computed Doppler velocities are fed back to the numerical simulation. The transient and steady characteristics of the UMI simulation have been revealed. In this paper, we performed the numerical experiment aiming at the reproduction of the three-dimensional unsteady flow field. As the result, the application of the feedback in the UMI simulation made the computational results converge and trace to the model of real blood flow.
View full abstract
-
Akira SUZUKI, Takuji KOIKE, Sayuri MURAKAMI, Kyoji HOMMA
Article type: Article
Session ID: 638
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
When a skull is vibrated by a vibrator, we can perceive a sound. The applied vibration is supposed to be transmitted to the cochlea through the temporal bone, and this sound path is called bone-conduction. However, our preliminary experiments showed that sound pressure is generated in the external auditory meatus when a skull is vibrated, and the sound pressure strongly influences perception of sound at low frequencies. In this study, the sound pressure in the external auditory meatus generated by the vibration of 0.2〜40kHz applied to a skull was measured. The results showed that the influence of the sound pressure generated in external auditory meatus on perception of the sound decreases with increasing the frequency.
View full abstract
-
Yuta YAMANOI, Ryosuke KOMIYA, Tsutomu TAJIKAWA, Atsushi SAKURAI, Kiyos ...
Article type: Article
Session ID: 639
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Bronchial asthma is a kind of chronic bronchitis. It causes an airway narrowing and so makes breathing difficult. It is important to clarify its mechanism. The characteristic of asthmatic airway is that its bucked cross-section consists of many folds in the airway lumen. It is considered to be caused by a rapid constriction of smooth muscle. We paid attention to a rapid change in the transmural pressure as a model of the constriction of smooth muscle. In this study, to clarify the mechanism of the buckling, we used two-layered collapsible tubes as a model of the airway and used a shock tube which gave a sudden decrease in the pressure inside the collapsible tube. The cross-sectional shape of the tube was visualized by a laser sheet method and its behavior during the buckling was photographed by using a high speed video camera. We examined the influence of wall structure and Young's modules of the tube on buckling behavior.
View full abstract
-
Naoya Takeuchi, Kiyoshi Bando, Tsutomu Tajikawa, Kenkichi Ohba, Yasuo ...
Article type: Article
Session ID: 640
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Surgery to relieve nasal hypertrophy is always performed without quantitative measurements of the effect on the airflow. In order to build up the objective measuring method of airflow in the human nasal cavity, the 3-dimensional numerical model in the human nasal cavity, concluding the nasopharynx was reconstructed from CT scans of a healthy nose. The airflows of the numerical model at inspiration and expiration as steady flow are analyzed by using finite element method (FEM). As a result, during inspiration, the most airflow in numerical model passed a middle meatus and an inferior meatus. The airflow at expiration also showed the same tendency as that of inspiration. During inspiration and expiration, the airflow in the superior meatus having the function of olfaction was small. Meanwhile, there were articulate differences between right and left nose in point of the velocity distribution.
View full abstract
-
Takashi Ando, Hikaru Aono, Hao Liu
Article type: Article
Session ID: 641
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Aiming at providing instructive aerodynamic principles for the MAV (Micro Air Vehicle) design of a mini-helicopter, aerodynamic characteristics of rotary wings of insect and bird sizes were studied numerically using a biology-inspire dynamic flight simulator. A geometrical model was built based on a realistic insect body and wings ; a rotating angular velocity for the rotary wing is defined to be identical with that of a flapping insect wing ; and an angle of attack is taken to be equal to the mean angle of attack of the flapping wing. Computations of hovering aerodynamics of the insect-type, mini-helicopter were conducted with a specific focus on the effects of the size which varied over a wide range of 1〜10000, and the reduced frequency at 0.382, 0.764 and 1.146. Our results indicate that the LEV (leading-edge vortex) is observed at all the Re numbers detached onto the upper surface of the wing and is responsible for the lift generating as seen in a flapping wing of insect flight. Furthermore, the computed CT/CQ is clearly sensitive to the Reynolds number rather than the reduced frequency.
View full abstract
-
Tamotsu MURAKAMI, Yoshikazu BABA, Kentaro HIROTA
Article type: Article
Session ID: 701
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Technologies for artificial bone which is gradually absorbed into existing bone and finally becomes an integral part of human bone have recently been studied intensively. Solid freeform fabrication technologies enable us to fabricate such artificial bone with any appropriate three dimensional shapes for each patient's body part and case. This paper reports a trial of solid freeform fabrication of artificial bone with three dimensional distribution of porosity (high porosity for high absorbency into existing bone and low porosity for mechanical strength) using stereolithography with three dimensional dithering of the slurry of β-TCP (β-tricalcium phosphate) powder and photopolymer resin.
View full abstract
-
Takashi Hayami, Tadashi Shibue, Shigeki Hontsu
Article type: Article
Session ID: 702
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In developing artificial cartilage, made from poly(vinyl alcohol) hydrogel (PVA-H), it is important to develop a method for imparting cell attachment to certain areas of PVA-H surface because PVA-H itself has very poor biocompatibility. In this experiment, hydroxyapatite (HA) thin film 300nm thick was deposited by pulsed laser deposition technique on PVA-H. And the interaction between PVA-H and mouse fibroblast was examined by a cell culture method. The cell attachment on HA coated PVA-H (water content 33%) showed the maximum that was as high as commonly used tissue culture dish. Although higher water content (53%) PVA-H, this technique was effective in the improvement of cell attachment. Pulsed laser deposition is novel technique for quick and firm attachment between PVA-H and the underlying bone.
View full abstract
-
Hajime FUKUNAGA, Yoshihiro TAKEDA, Michihito AOKI, Sayuri MURAKAMI, Ta ...
Article type: Article
Session ID: 703
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The byssus secreted by marine mussels have adhesive plaques renowned for their great adhesive characteristics. Dopa contained in the byssal protein can form catechol complexes with exceptional stability in the presence of metal ions such as Fe3+ while mussels take up particulate or soluble iron from seawater. Iron may be the key reagent in protein cross-linking for adhesive synthesis, but the implications for their adhesive strength have not been clarified. The peeling strength of adhesive plaques deposited onto glass surface, which secreted by the mussels exposed in Fe3+ supplemented seawater for 24 hours, has been investigated by peeling apparatus exclusively for the mussel plaques. The peeling test showed that keeping plaques in the high iron seawater altered its tenacity as contrasted with that kept in artificial seawater manipulated its pH same as the other level.
View full abstract
-
Kazuya SAWADA, Dohiko TERADA, Kenichi YOSHIDA, Seiichi FUNAMOTO, Toshi ...
Article type: Article
Session ID: 704
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Decellularization of biological tissue has been investigated using supercritical fluid extraction method. Carbon dioxide and fluoroform which have gentle critical conditions were applied as extraction media under various experimental conditions. Decellularization was evaluated by means of HE-stain and chemical quantitative analysis of DNA and phospholipids. Supercritical carbon dioxide that contained small amount of entrainer had a potential to extract phospholipids and nucleus without losing mechanical strength of tissue. In addition, decellularization with carbon dioxide could be attained within 30 minutes treatments. On the other hand, treatments with supercritical fluoroform alone caused slight hardening of tissue.
View full abstract
-
Shinichi GOMITA, Takuji KOIKE, Sayuri MURAKAMI, Kyoji HOMMA
Article type: Article
Session ID: 705
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this study, individual differences in shape of the cochlea on hearing were analyzed by using three-dimensional finite element models of human cochlea. Dynamic behavior of the basilar membrane and cochlear fluid caused by the vibration of the stapes footplate was analyzed, and the effects of the length and width of the basilar membrane, and Young's modulus of the round window on the vibration of the cochlea were examined. The results suggested that the individual differences in size of the cochlea did not have the great influence on the vibration mode of the basilar membrane, especially on the distribution of the characteristic frequency of the basilar membrane.
View full abstract
-
Shouichi SUGINO, Yousuke KITAJIMA, Masao WATANABE, Yoshinori SAWAE, To ...
Article type: Article
Session ID: 706
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Articular cartilage is charactericstic tissue which is mainly composed of avascular extracellular matrix. Solute transport in articular cartilage is to mainly by diffusion across the articular surface. We engineered regenerated cartilage by seeding bovine chondrocyte into agarose gel as scaffold. We evaluate diffusion coefficient by using fluorescent molecular with image process and to examine the effect of molecular weight and electric property of fluorescent labeled dextran on diffusion process in regenerated cartilage tissue.
View full abstract
-
Natsuko HOSODA, Nobuo SAKAI, Yoshinori SAWAE, Teruo MURAKAMI
Article type: Article
Session ID: 707
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Cartilage tissue has a high water content. The mechanical behavior of cartilage is complicated because the components of cartilage tissue are inhomogeneous. The aim of this study is to consider the effect of Young's modulus distribution on mechanical behavior of cartilage tissue by two dimensional finite element method (FEM). In this study, Young's modulus distribution is expressed as a function of depth and time. The numerical result with Young's modulus distribution as a function of depth showed that the calculated deformed profiles immediately after loading correspond to actual profiles. The introduction of the time dependent value of Young's modulus could satisfactorily simulate the load carrying load of cartilage in the experiment.
View full abstract
-
Kazuaki NAGAYAMA, Akira TSUGAWA, Takeo MATSUMOTO
Article type: Article
Session ID: 709
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Effects of actin filaments (AFs) and microtubules (MTs) on quasi-in situ tensile properties and internal tension at a whole-cell level were studied in rat aortic smooth muscle cells (SMCs) cultured on substrates. SMCs were held with a pair of micropipettes maintaining their shape on the substrate. Tensile tests up to〜10% strain were performed for 3-4 times both before and after administration of cytochalasin D or colchicine. Force-elongation curves became stable after second cycle of loading/unloading process. The cell stiffness defined as the average slope of loading curve in stable loops were decreased by〜70% after AF disruption with cytochalasin D. Treatment with colchicine, a MT disrupter, decreased cell stiffness by〜30%. The cell height significantly increased with AF disruption, while it decreased with MT disruption. These results indicate that not only AFs but also MTs play crucial roles in maintaining whole-cell stiffness of SMCs, and while AFs act as an internal tension generator, MTs may act as a tension reducer.
View full abstract
-
Hiroshi YAMADA, Norihide MOURI
Article type: Article
Session ID: 710
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We measured the contours of cultured endothelial cells on a silicone substrate in unstretched and stretched states. Cells were scanned by confocal laser scanning microscopy. The interval of each image was 0.25μm in the vertical direction. The outline of each horizontal cross section of the cell was identified using a threshold of the fluorescence intensity. The error in the position of the outlines caused by the fading intensity of fluorescence was <1μm except the top region of the cell. For stretched cells, the difference in the position of the outlines between the results from the measurement and those from the finite element analysis was also <1μm except the top region. This indicates that a neo-Hookean material model describes the three-dimensional deformation under substrate stretching well.
View full abstract
-
Tadashi UMEZAKI, Yoshinori SAWAE, Emiko SUZUKI, Teruo MURAKAMI
Article type: Article
Session ID: 711
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Articular cartilage tissue is composed of extracellular matrix which is mainly consisted of proteoglycan and collagen. It develops superior dynamic functions such as lubrication and load carrying capasity. And, collagen network structure, cell shape and cell density are different by the stratum. A difference of such structure formation becomes one of the factors to realize high functionality of cartilage. It was shown that the formation of a collagen network is different depending upon the density and shape of a gel specimen when we use agarose for scaffold with cultured chondrocytes.
View full abstract
-
Noritaka YAMAMOTO, Naoki Sakamoto
Article type: Article
Session ID: 712
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The fascicles obtained from mouse tail tendons were immersed in a collagenase solution. These fascicles were stretched to failure. Microstructure of the fibrils obtained from these fascicles was observed with a dark-field microscope and atomic force microscope. Decomposition of collagen molecules induced the breaking of these fibrils. Therefore, the tensile strength and strain at failure of these fascicles were decreased.
View full abstract
-
Tsubasa MATSUI, Toshiro OHASHI, Shinji DEGUCHI, Masaaki SATO
Article type: Article
Session ID: 713
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In our previous study, tensile properties of single stress fibers (SF) chemically isolated from vascular smooth muscle cells have been investigated. Tensile tests were performed at a single strain rate of 0.02s^<-1>. In this study, the strain rate dependency of tensile properties of SF was investigated. The results showed that averaged force-strain relationships were found to be almost linear in the physio-logical strain range of 0.0-0.4 for 0.01s^<-1> and 0.05s^<-1>. In contrast, the force-strain relationship was nonlinear for the 0.1s^<-1> strain rate. The reason for this difference is unclear, however possibly due to a presence of threshold in strain rate between 0.01s^<-1> and 0.1s^<-1>. Moreover, microstructural canges of SF during stretching were investigated using a speckle fluorescent microscopy technique. SF were labeled using Quantum Dot in dotted pattern to analyze local strain in SF. The results showed that local stretch ratio was nonuniformly distributed through the length of the SF. This approach may provide further insights to SF biomechanics.
View full abstract
-
Yoshitaka SHIMADA, Taiji ADACHI, Sadami TSUTSUMI
Article type: Article
Session ID: 714
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Actin filaments are the most abundant component of cellular cytoskeleton. To understand actin polymerization is important in the field of cell biomechanics. The purpose of this study is to develop the computational simulation system to calculate actin polymerization dynamics from a single actin monomer to many filaments. We propose a mathematical model describing actin monomers polymerization to the tip of barbed ends of actin filaments, using Brownian dynamics method. Results obtained from this model are 1) dependency of actin concentration on actin filament elongation rate, and 2) the process of assembling and elongation in actin filaments.
View full abstract
-
Ryo MATSUDA, Taiji ADACHI, Masahiro SOKABE, Masaki HOJO
Article type: Article
Session ID: 715
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Biomechanical factors are considered as crucial modulating factors in dynamic actin polymerization and depolymerization. From this view, it is important to investigate mechanical behavior of actin filament under the influence of various mechanical condition induced by tensile force and structure deformation. The aim of this study is to investigate method of calculating stiffness of actin filament structure. For this purpose, we performed steered molecular dynamics (SMD) simulation in order to study molecular response based on a two-spring model connected in series. Using this method, we calculated stiffness of actin filament subject to tensile force along its longitudinal axis. The results showed that an elastic behavior was observed in elongation range of 0-0.12% actin filament consisting of 14 actin molecules and in this region stiffness for actin filament depended on tensile velocity. We estimated by extrapolation that the stiffness for 1-μm-long actin filament was 57.8 [pN/nm] under condition in which tensile force is applied slowly enough. The order of this simulation agreed with that of experimental results.
View full abstract
-
Kenichiro KOSHIYAMA, Tetsuya KODAMA, Takeru YANO, Shigeo FUJIKAWA
Article type: Article
Session ID: 716
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The diffusion process of a 5-fuluorouracil (5FU) in the water layer confined by two leaflets of lipid monolayer is elucidated by molecular dynamics simulation. The calculated diffusion constant of 5FU is 1.1×10^<-5>cm^2/s in bulk water with SPC/E water model at 25℃. This is in rather good agreement with that obtained in a recent NMR experiment (1.0×10^<-5>cm^2/s). It is found that the diffusion constant of 5FU in the confined water layer decreases as it moves from the center of the water layer toward the lipid monolayer surface. This decrease may be caused by the effect of the charges of the hydrophilic head groups of the lipid molecules.
View full abstract
-
Yoichi TAGAYA, Shingo YONEOKA, Hedong ZHANG, Kenji FUKUZAWA, Masakazu ...
Article type: Article
Session ID: 717
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We have demonstrated effective biomolecule separation methods based on size exclusion chromatography (SEC) type separation using nanostructured channels constituted with a flat pillar matrix and a convex pilar matrix. The performances of biomolecule separations were compared between different applied voltages and between the flat and convex pillar matrices. In the SEC type separation using the flat pillar matrix, the narrow lanes were designed for the passages for smaller molecules to detour. The specific feature of the convex fence matrix is that the lane width is changed at the halfway of the lane length. It was found from the result of the separation of λ-Hin d III digest (125-23130bp) that the separation resolution of the long DNA was highest for the lowest voltage of 20V. In contrast, the result of the separation of φX 174-Hae III digest (72-1353bp) showed that the separation resolution of the short DNA was highest for the highest voltage of 100V. In addition, it is interesting to note that the convex fence matrix enabled us to separate the peaks of 4, 6 and 9kbp fragments from the peak of 23kbp, while those peaks overlapped each other for the flat fence matrix.
View full abstract
-
Rei YASUMURO, Taiji ADACHI, Hiroyuki KABATA, Masaki HOJO
Article type: Article
Session ID: 718
Published: September 15, 2006
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 stereo selectivity. Here, we tried to construct several-nm-radius rings from ssDNA, as in the simplest system of design and construction of the nano-structural elements. Two kinds of ssDNA were designed, the body of the ring (Precursor) and a mediator that brings the DNA ends together (Template). Precursor was circularized by both Template and a ligating enzyme as designed, and formed the nano-rings in a topoisomeric fashion. Resultant products were further analyzed with exonuclease digestion for the confirmation of circularization.
View full abstract
-
Katsuya SATO, Yutaka MIKI, Kazuyuki MINAMI
Article type: Article
Session ID: 719
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Cell adhesion plays a crucial role to maintain a cell shape and a tissue structure. Therefore, in tissue engineering, cell adhesion control is an essential factor to induce artificial tissue reorganization. Then in cell biomechanics, innovation of observation technique has brought a high spatial and temporal resolution. This innovation of observation object also requires accurate cell adhesion control to maintain cell position and cell shape. In this study, we proposed a novel surface modification process to make a micro cell adhesion pattern. Fluorine polymer was coated onto a cover glass, and micro hydrophilized pattern was fabricated by using a stencil mask and exposure to O_2 ion flux or O_2 plasma. To evaluate an effect of hydrophilization treatment, modified surface of cover glass was observed using optical microscope, and a contact angle of water on the modified surface was measured.
View full abstract
-
Tadayoshi EGUSA, Zhongwei JIANG, Tetsuyou WATANABE, Makoto YOSHIMOTO
Article type: Article
Session ID: 720
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This study is to investigate the ultrasonic characteristic from the medicine(fluorescet substance) of encapsulated liposomes by irradiating liposomes by ultrasonic. Liposome which is consisted of lipid from biomenbrance is expected to the application to drug delivery system (DDS). therefore, I have examined the influence to liposome from ultrasonic by pasting a piezoelectric element on a glass cell.
View full abstract
-
Takamasa SONODA, Toru TOKUYAMA, Eizi HAYASHI
Article type: Article
Session ID: 721
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this research, it has aimed the development of combined sense system that uses the sense of force feedback with the visual by the shape of microscopic features of a micro sample. The visual and the sense of force feedback are expanded and it aims at the efficiency improvement of the operation skill of the micro sample by working in the condition similar to actually feeling that operates the one of size that we can actually grip by finger. As this basic research, we use a haptic device and it presents the expanded reaction force which virtual object of a micro sample has.
View full abstract
-
Nahoko YAMAMURA, Akinori UEDA, Ryo SUDO, Mariko IKEDA, Kazuo TANISHITA
Article type: Article
Session ID: 723
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We clarified the effect of mechanical property of substrate on the microvessel network formation by cultured Bovine Pulmonary Microvascular Endothelial Cells (BPMECs). The type I collagen gels, with different elasticity were polymerized at pH 5 (E=4500±1500Pa ; flexible gel), at pH 9 (E=20800±3100Pa ; rigid gel). In the flexible gel, network structure formed by connection between elongated and sprouting cells and network density is larger. The cells in the rigid gel tend to generate aggregates. Furthermore we confirmed the lumen surrounded with a single cell for flexible gel and lumen surrounded by two cells in rigid gel. Thus this result demonstrated that the mechanical property of extracellular matrix greatly plays a major role for the network formation.
View full abstract
-
Ken HASHIMOTO, Noriyuki KATAOKA, Emi NAKAMURA, Katsuhiko TSUJIOKA, Fum ...
Article type: Article
Session ID: 724
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The effects of oxidized LDL (oxLDL) on monocytes transendothelial migration (TEM) were investigated with an in vitro 3D-live-cell TEM assay system. Nevertheless, oxLDL did not enhance initial monocyte adhesion to endothelium and monocyte locomotion speed on EC's, total number of migrated monocytes was increased with oxLDL. OxLDL upregulated PECAM-1 and downregulated VE-cadherin on endothelial junctions without monocyte addition, both of which could promote monocyte entry by enhanced homophilic binding to monocyte PECAM-1, and by disrupted junctional barrier, respectively. These data indicate that before monocyte adhesion, endothelial junctions changed their conformation to more monocyte-acceptable state response to oxLDL, resulting the stage-specific promotion of monocyte TEM (stage initiation of invasion) with no enhancement of its initial adhesion or migration speed.
View full abstract
-
Shogo KURETOKO, Makoto HOSOBUCHI, Susumu KUDO
Article type: Article
Session ID: 725
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A phenomenon has been observed in which intracellular Ca^<2+> concentration in endothelial cells increases upon application of shear stress (Ca^<2+> response). It is therefore assumed that Ca^<2+> is the second messenger in the transfer of shear stress stimulation into cells. The Ca^<2+> response is also known to spread to surrounding cells (Ca^<2+> wave propagation). The present study investigated the effects on Ca^<2+> spread among cultured bovine aorta endothelial cells (BAECs) upon inhibiting the main intercellular signaling pathways, such as gap junction and paracrine pathways (apyrase, ARL67156, Thapsigargin, GdCl_3), by inducing Ca^<2+> wave propagation due to an intracellular InsP_3 elevation using caged InsP_3.
View full abstract
-
Shigeru TADA, Ken OKAZAKI
Article type: Article
Session ID: 726
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The physiological and pathophysiological mechanisms linked to reactive oxygen and nitrogen species in arterial vessel and tissue are not well established because the predictions and results in the past were not in agreement. In order to address the role of nitric oxide and its downstream mechanism in the localization of atherosclerosis, the effects of mass transport and hemodynamics on endothelial cells functions were investigated. An experiment model that simulates in vivo spatial patterns of flow separation, recirculation, and reattachment have been developed to examine the release of nitric oxide from the endothelial cell layer in response to the shear stress with a complex spatial variation. Direct exposure of cells to 20dyne/cm^2 shear stress after the onset of flow induced a rapid elevation in the nitric oxide release in the first ten minutes followed by a less rapid production. A mathematical mass transport model was constructed in the geometry mimicking the experimental flow domain to follow coupled biochemical reactions and diffusion of oxygen, nitric oxide, superoxide, and peroxynitrite, around the recirculation region. Steady state mass transport in nitric oxide, oxygen partial pressure and the associated production of peroxynitrite were predicted. The mass transport model provides an objective way to evaluate the relative influence of mass transport and hemodynamics on biochemical pathways related to the initiation of atherosclerotic lesions.
View full abstract
-
Shiro SUETSUGU, Masaaki TAMAGAWA, Jyun FUJII
Article type: Article
Session ID: 727
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, to investigate the effects of shock waves on the endothelial cells in vitro, Gene expression of the cells by plane shock waves are measured by Real-Time PCR. After working shock waves on suspended cells, Quantity of growth factor are increased. It is shown that the growth rate of suspended endothelial cells are accelerated by plane shock waves. To clarify these stimulation on the cell, shock wave propagation is investigated into cell by finite element method. The result show that, a high shear stress is caused by the shock wave in the cell membrane, and the frequency and the amplitude of the maximum shear stress is increased when the rise time of the shock wave is small.
View full abstract
-
Naoto KAWASAKI, Hiroki NAGAOKA, Susumu KUDO
Article type: Article
Session ID: 728
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Understanding the mechanisms involved in cell construction requires a method for visualizing the activity of the various factors responsible. This is particularly useful for observing signal transduction which involves the coordination and intracellular transport of signaling factors. Consequently, to understand signal transduction, it is important to visualize diffusion and transport of signaling factor. While fluorescent recovery after photobleaching (FRAP) is usually used to visualize intracellular transport and lateral diffusion of the proteins on cell membrane, we chose a new method involving the use of the photochromic protein, "Dronpa", to visualize diffusion and measure cell activity. The method enabled us to select and visualize cellular components at a variety of spatial scales using a fluorescent probe. By transfection of Bovine arterial endothelial cells (BAECs) to express Dronpa, we were able to visualize the fluorescent diffusion of Dronpa in the cytoplasm. Interestingly, cytoplasm diffusion is not isotropic.
View full abstract
-
Yoshihisa FUJISHIMA, Daisuke KATAKAI, Kiyoto NAGAI, Wataru ANDO, Kousu ...
Article type: Article
Session ID: 729
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Synovium cells obtained from the synovial membranes of porcine knee joints were cultured in DMEM in monolayer. After the cell density reached to 4.0×10^6 cells/dish, 2mM of ascorbic acid 2-phosphate was injected to promote the synthesis of extracellular matrix. Several days to one month after the injection, the synthesized matrix was manually detached from the substratum, and was then allowed active contraction for 1 hours to develop 3DSTs. A cyclic tensile force with the maximum force of 0.01N was applied to the 3DST for 1 hour a day in DMEM in an incubator. Tensile properties and micro structure of the 3DST were determined using a tensile tester and a differential interference contrast microscopy, respectively. Results revealed that the collagen fibers in the 3DST were closely aligned with the direction of tensile force application. The modulus of the 3DST became higher as compared with no-loaded control 3DST. These results suggest that 3DST changes its mechanical properties and structure in response to externally applied tensile force.
View full abstract
-
Yoshihiro UJIHARA, Kenta OKADA, Hiroshi MIYAZAKI
Article type: Article
Session ID: 730
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Tensile properties of fibroblasts obtained from rabbit patellar tendons were determined after F-actin and microtubules were disrupted separately or simultaneously. Intracellular F-actin and microtubules were disrupted with cytochalasin D and colchicine, respectively. Each cell was attached to the fine tips of a micropipette and a glass microplate, and stretched at the rate of 6μm/s. The stiffness of cells significantly decreased by the disruption of F-actin, while microtubule disruption did not affect the stiffness, where the stiffness was defined by the slope of each load-elongation curve between 0 and 20μm elongation. The stiffness of cells treated with cytochalasin D and colchicine simultaneously was almost the same level as that of cells treated with cytochalasin D alone. These results suggest that F-actin is major component which is responsible for the tensile properties of fibroblasts and microtubules and interaction of F-actin and microtubules don't contribute to the tensile properties of fibroblasts.
View full abstract
-
Shinichi ITO, Mototsugu TANAKA, Taiji ADACHI, Hiroshi KAMIOKA, Teruko ...
Article type: Article
Session ID: 731
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Osteocyte network system embedded in bone matrix is considered as one of the important elements in the mechanosensory system in bone remodeling. In order to understand the mechanosensory mechanism of osteocytes network, it is essential to evaluate mechanical stimulation to osteocyte network quantitatively as well as to observe biochemical response of osteocyte network to deformation of bone matrix. This study aimed to develop the method to evaluate osteocyte network deformation against bone matrix deformation. Osteocyte network in chick calvarial bone tissue was visualized by immunostaining of cell membrane using OB7.3. Osteocyte network displacement induced by localized deformation to bone matrix using a glass microneedle was observed. Analysis of osteocyte network displacement was fairly successful using the image-correlation method. Applicability of the method newly developed in this study was discussed in combination with biochemical response observation of change in intracellular calcium ion concentration using the fluorescent ratiometry method, in order to investigate the relation between macroscopic deformation of bone matrix and microscopic cellular response.
View full abstract
-
Yuki AONUMA, Mototsugu TANAKA, Taiji ADACHI, Hiroshi KAMIOKA, Teruko Y ...
Article type: Article
Session ID: 732
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The osteocyte is considered as a candidate of the mechanosensory cells in bone tissue. In order to understand the mechanosensory mechanism of osteocytes, it is essential to evaluate mechanical stimulation to osteocytes quantitatively as well as to observe biochemical response of osteocytes to mechanical stimulus. This study aimed to develop the method to evaluate and control mechanical stimulation to osteocytes. Microbeads coated with OB7.3 were attached to chick calvarial isolated osteocytes. Mechanical stimulus applied by pushing microbeads using a glass microneedle was successfully evaluated and controlled. Change in the intracellular Ca^<2+> concentration induced by localized mechanical stimulation by a microneedle was observed using a confocal laser-scanning microscope. Calcium signaling response was up-regulated by mechanical stimulation to proximal base of cell process, while it was not up-regulated by mechanical stimulation to cell body.
View full abstract
-
Takanobu FUKUNAGA, Kosaku KURATA, Junpei MATSUDA, Hidehiko HIGAKI
Article type: Article
Session ID: 733
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Bone is continuously subjected to repetitive loading, which leads to microdamage even if the strain level is within physiological range. The damaged site must be sensed and promptly repaired by remodeling process ; otherwise the accumulation of microdamage results in bone fracture. The aims of this study were, therefore, to establish a relevant in vitro model for studying mechanical responses of stretched osteocytes in three-dimensional culture, and to examine the role of osteocyte in the initial phase of bone resorption. We established a loading apparatus in which osteocyte-like cell line MLO-Y4 cells were three-dimensionally cultured inside collagen gel and subjected to cyclic stretching in over-physiological strain level. Excessive stretching at 10000με damaged the gel-embedded osteocyte, resulting in significant amount of cell death. Culture medium obtained from the damaged osteocyte contained both M-CSF and RANKL, which induced significant amount of TRACP-positive cells in bone marrow culture. It suggests that the local death of osteocytes provides an important mechanism to target bone resorption to microdamaged site.
View full abstract
-
Shogo MIYATA, Tomokazu NUMANO, Kazuhiro HOMMA, Katsuko FURUKAWA, Tetsu ...
Article type: Article
Session ID: 734
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Applying tissue-engineered cartilage in a clinical setting requires an non-invasive evaluation method to assess biomechanical property as well as biochemical property. Magnetic resonance imaging (MRI) represents potential approach to assess material properties of the engineered cartilage. In this study, we attempt to establish the non-invasive assessment method of the tissue maturation of the engineered cartilage using quantitative MRI. To reconstruct cartilaginous tissue, bovine chondrocytes were embedded in agarose gel and cultured in vitro up to 4weeks. MRI-derived parameters (relaxation time: T1, T2 ; diffusion coefficient: D) were measured. After the MRI experiments, equilibrium Young's moduli were determined from stress relaxation tests and the sulfated glycosaminglycan (sGAG) concentration was measured by DMMB assay. As a result, the diffusin coefficient showed a highest correlation with the equilibrium Young's modulus and sGAG concentration. In conclusion, MRI measurements can be useful predictors of the degree of cartilaginous tissue formation.
View full abstract
-
Toshiro OHASHI, Junichi YAMAZAKI, Masaaki SATO
Article type: Article
Session ID: 735
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Although cellular traction forces are believed to play an important role in the interactions between cells and their substrates, little is known of the effect of mechanical environment on the magnitude and direction of traction forces and hence how intracellular structures contribute to traction forces. In this study, microfabricated substrates, array of micropillars with different spacing, were used to estimate cellular traction forces of smooth muscle cells, particularly exploring the contribution of microtubules to traction forces. A significant increase in traction forces from 15.2±1.4 to 22.4±1.8nN was found by increasing the spacing of the microposts from 6μm to 10μm, although organization of stress fibers was less observed. This result indicates that, for the 10μm spacing, actomyosin interactions may be activated, producing higher traction forces per microposts. In addition, when microtubules were disrupted, a 30% increase in traction forces was observed in cells plated on both sets of microposts. This result suggests that the increase in traction forces after disruption of microtubules is mainly not due to an activation of actomyosin interactions but possibly due to structural changes caused by the loss of microtubules networks.
View full abstract
-
Shuichiro FUKUSHIMA, Ryuichi NAKAYAMA, Takeshi YASUI, Tsutomu ARAKI
Article type: Article
Session ID: 736
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Second-harmonic generation (SHG) microscopy provides non-staining observation of collagen structure. Thereby we observed remodeling of collagen gel, in which fibroblasts were embedded or on which endothelial cells (ECs) were cultured. The intensity of SHG light from a fibroblast-embedded gel progressively increased during 7-day culture. In a gel cultured with ECs, SHG intensity markedly increased until day 2, and then the increasing rate of SHG light was decreased. The observation that high SHG intensity area was associated to cell location indicates that the change of SHG intensity was due to interaction between cells and collagen. Because the quantity of collagen produced by cells was insignificant, mechanical interaction is probably major factor.
View full abstract
-
Kennedy O. OKEYO, Taiji ADACHI, Masaki HOJO
Article type: Article
Session ID: 737
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Recent analysis techniques of Fluorescence Speckle Microscopy (FSM), and Particle Imaging Velocimetry (PIV)-incorporated Image Correlation have been utilized for quantitative characterization of cytoskeletal actin dynamics in the lamella region of crawling fragments from fish keratocyte as simplified locomotory systems. Our aim is to elucidate how mechanical factors regulate actin structure reorganization, and therefore cell motility, by carrying out a quantitative analysis of the mechanical state of cytoskeletal actin structure in the lamella region of crawling keratocyte fragments. We show that a net compressive strain exists in the lamella region and point out its role as a potential regulator of the reorganization process through the modulation of actin depolymerization. Our results highlight the importance of mechanical factors in the regulation of directional cell motility.
View full abstract
-
Makoto MIYOSHI, Shigeru KUCHII
Article type: Article
Session ID: 738
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This research concerns developing the technique for analyzing various functions in the cell by making three-dimensional image maps from the successive section images of the fluorescently-stained cell that are acquired with a confocal laser scanning microscope (LSM). The distribution of fluorescence in the cell that is incomprehensible in two-dimensional image analysis can be investigated by three-dimensional image analysis. In the successive section images acquired with LSM, there are a lot of noises that disturb the construction of the three-dimensional image. Removing them without loss of the original information is an important problem to be solved. And, we succeeded in the development of the effective image processing method to achieve this and the method of the display that facilitates the observation of the fluorescent distribution. We removed the noises in the images of the stained nucleus and antibody cell, and then we actually analyzed it by making the three-dimensional images.
View full abstract
-
Daisuke NOMURA, Shigeru KUCHII
Article type: Article
Session ID: 739
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The purpose of this research is the observation of cell reactions by an electromagnetic wave. We study the microwave applicator for in vitro research and examine the device with simulation to decide the optimum condition. The simulation with Finite Difference Time Domain (FDTD) method has an assumption that Cell Biology Experiment Facility (CBEF) is attached to the bottom of waveguide which is sealed with a metal plate and the waves enter from the other open side. This report shows the Specific Absorption Rate (SAR) of cell and electric field intensity in the facility. We also propose the exposure system which can irradiate living cells with the microwave efficiently.
View full abstract
-
Masayuki OGAWA, Fuminori WAKE, Kazuaki NAGAYAMA, Yojiro ISHINO, Takeo ...
Article type: Article
Session ID: 740
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A cell rotation system (CRS) has been developed to observe three dimensional (3D) morphology of cells precisely from their images obtained from various points of view. In this system, a cell held with a micropipette under a microscope is rotated around the axis of the micropipette set perpendicular to the optical axis, while the pipette tip is kept in position based on the binarized image of the pipette tip. In this study, distributing back projection (DBP) method that is one of the computerized tomography (CT) algorithms is applied to obtain clear 3D images of intracellular structure such as nucleus and cytoskeleton. The reconstructed images were clear and we could observe details of 3D structures of nucleus and actin filaments. The 3D reconstruction with CRS would become a powerfull tool for detailed observation of various intracellular structures.
View full abstract
-
Akihiro SHIMONO, Katsuya SATO, Kazuyuki MINAMI
Article type: Article
Session ID: 741
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
It is believed that cells can sense force and deformation, and it is one of the most important research objects in the field of cell biomechanics to clarify the cellular mechano-sensing mechanism. Many experimental studies have been conducted to evaluate the cellular response to applied mechanical stimulus. In most of these studies the size of mechanical stimuli loading device were relatively large compared to the single cell size. In addition, the evaluation of mechanical condition was conducted in macro level. Although the innovation of observation apparatus brought us extremely high spatial and temporal resolution, the size of mechanical stimulus loading device limited to design fine experimental system to observe the cellular response with submicron or nano-level and millisecond order. In this study, we proposed a novel fabrication process to make a silicone elastomer microstructure. This silicone elastomer microstructure was designed to aim at a mechanical stimuli loading device for a single cell level. A test piece was designed and fabricated to confirm the productivity of proposed process.
View full abstract
-
Mitsuhiko NAKATSUJI, Kazunori FURUKAWA, Eiji NAKAMACHI
Article type: Article
Session ID: 742
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this study, a new head injury criterion, which is evaluated by using the tension test, is proposed. In order to obtain the threshold value for brain's organ and tissue, the in vitro tension tests of cultured nerve cells were performed. PC12 cultured nerve cell was adopted to imitate the human's nerve cell. In the experiments, various strain were generated by micro manipulater. Relationships between the tensile strain and the damage of the higher-order function of the neuronal cell were obtained.
View full abstract
-
Hidetoshi NAKAMURA, Kazunori FURUKAWA, Eiji NAKAMACHI
Article type: Article
Session ID: 743
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this study, we attempted to develop a new head injury criterion which is evaluated by the hydrostatic pressure in the head crash accident. This pressure is mostly occurred in the pedestrian during a collision. Main subject of this study is to find the threshold value of the functional injury of the brain obtained by the impact experiment. We used the hydrostatic pressure as a criterion value by measuring PC-12 cultured nerve cell injury. PC-12 cultured nerve cell was employed to imitate the human's nerve cell. We observed cytoskeleton injury caused by the hydrostatic pressure loading. It reveals that the cytoskeleton injury depends on the hydrostatic pressure, and the injury threshold value was obtained. It was concluded that a new head injury criterion based on the nerve cell injury was established.
View full abstract
-
Osamu KUWAZURU, Jariyaporn SAOTHONG, Nobuhiro YOSHIKAWA
Article type: Article
Session ID: 744
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We investigate the effect of dermal aging on the wrinkle property of human facial skin. Wrinkle property is evaluated by the finite element buckling analysis considering the layered structure of skin. The solar elastosis, which is a result of the photoaging and increases abnormal elastic fibers in the papillary dermis, has been thought as a major cause of the formation of permanent wrinkles on facial skin. Moreover, from the mechanical standpoint, the flattening of dermal-epidermal junction caused by the intrinsic aging may also affect the permanent wrinkle formation. Through some numerical examples, we discuss the effect of the thickness change of papillary dermis and the shape alteration of dermal-epidermal junction on the wrinkle property, and approach to a reliable scenario of the wrinkle formation mechanism.
View full abstract
-
Hirofumi SHINTAKU, Teru OKITSU, Shinichi MATSUMOTO, Satoyuki KAWANO, T ...
Article type: Article
Session ID: 745
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, we investigated the effect of the fluid dynamical stress on islets during islet purification process. Firstly, we developed a fracture model of islets in a shear flow by the fracture test using a cylindrical viscometer. Secondary, we conducted the numerical calculation to estimate the fluid dynamical stress and strain energy during islet purification process. Finally we predicted the islet size reduction during islet purification using the fracture model and the numerical results. Comparing experimental data and numerical result in terms of the islet size reduction, it is confirmed that the fluid dynamical stress during the islet purification damages islets.
View full abstract
