Recently, various studies of Micro Air Vehicle (MAV) and Unmanned Air Vehicle (UAV) have been reported from wide range points of view. The aim of this study is to research the aerodynamic improvement of a flapping wing in low Reynold's number region to develop an applicative these air vehicle. The six kind of elliptical wings made of stainless steel are used in the flapping wing. The effects of flapping amplitude and wing configuration regarding the aerodynamic characteristics are investigated in detail. The fluid force measurement by six component load cell and PIV analysis are performed as the experimental method. In the flapping wing experiment, the simultaneous measuring of the fluid force measurement and PIV analysis is tried by using the trigger signal from the encoder attached to the flapping model. The relations between the aerodynamic superiority and the vortex behavior around the models are demonstrated.

Neutrophil is known as one of the immunological system, and it has chemotaxis by concentration gradient of cytokine. In general, the neutrophil is moved to high concentration of cytokine in the blood vessel, and derived to the inflammation areas. However, the mechanism of propulsion has not been elucidated yet. By understanding this mechanism, it can be applied to medical technologies such as drug delivery systems and micro machines. Therefore, it is necessary to elucidate the principle of neutrophil's propulsion. In our previous investigation, it was found that concentration gradient on the surface of neutrophil is reverse toward surrounding fluid. In this paper, detailed concentration distribution and concentration gradient on the neutrophil's membrane are examined by experimental. From the result, It was found that concentration gradient occurred by the decreasing of concentration at the neutrophil's membrane of cytokine insert side.

In late years a function and the structure of the creature called biomimetics are applied to technical development. We focused on the tuna that could swim in the water at high speed. A saw-like fin is between the tail and fins from the 2nd dorsal fin in fish like tuna. A fin of the triangle is called finlets, and there is in the back and ventral. It is thought that the finlets brings the effect that the flow behind the fish rectifies at present. Its role was inspected experimentally by the fluid force sensing using a made model. The experimental result by the fluid force measurement was not seen in the variation of the flow with or without finlets. The one when equipping finlets more than the time of non-equipment, indicated a higher C_D.

Evaluation of antithrombogenic property of cardiovascular devices, such as a ventricular assist device, is important at the design stage of development. Although animal experiments and animal blood experiments are conventionally performed for design evaluation, they required costs and periods of time. Thrombus mimetic testing method was proposed for mechanical ceirculatory support devices. In the method oil paint and surfactant were suspended in water and the resulting adhered paint was observed. In this study we applied the method to a centrifual blood pump to investigate the effect of washout holes on thrombus formation, using models of partially closed washout holes. The result was that paint adhered at the leading edge on impeller front side and at the rings of no relative velocity on impeller rear side. The results were similar to proceeding animal studies.

In our previous study, we obtained aortic wall samples with calcified plaques from autopsy and identified luminal surface strains under uniaxial stretch in circumferential direction using a 2D digital image correlation (DIC) technique and found zero strain on the plaque surface with calcified fibrous cap. In this study, we reconstructed a 3D geometry of the calcified region (CaR) and the aortic wall based on computed tomography (CT) scans of the samples. We created a 3D finite element (FE) model with CaRs and a homogeneous aortic wall model. The CaR caused zero strain on the plaque surface near the region of CaR, while the homogeneous wall model did not have such a small strain. Compared to the 2D analysis by DIC, the 3D FE analysis had a larger area of ≤0 strains, and similar areas with strains of ≤0.005, ≤0.01 and ≤0.02. FE modelling based on 3D geometry enabled one to correlate the luminal surface strains with the characteristic of the geometry of CaRs.

Most of spinal implants are made in foreign countries and do not necessarily match a build of Japanese. Therefore the form of the implant is confirmed by the appearance and QOL becomes the problem. Thus there is the problem that fitting force decreases while the use of a small implant device is desirable. In this study, the downsizing of the implant device namely a low profile examined it. The test materials made a set screw and a screw socket specimen of different 3Type of dimensions using Ti-6Al-4V. A removal torque value was measured after tightening of the set screw (Static load) and after give load to a rod repeatedly (dynamic load). The set screw was observed after examination using a SEM. The removal torque value decreased the removal torque value of Type 2 in comparison with Type 1. On the other hand, Type3 which assumed the same number of the threads Type1 was equal to a removal torque value of Type 1. As a result of observed the thread surface of the set screw, plastic deformation and an abrasion trace were observed. In addition, an opening of the upper screw socket was accepted in a fit state, and this situation was easy to loosen set screw.

In recent years, the demand for artificial joints has increased. As society has aged significantly, it has become necessary to increase the lifespan of artificial joints. The purpose of this study is to evaluate the effects of surface texturing, which is a technique of fine patterning the surface to modify the frictional behavior and corrosion resistance, on titanium materials that are widely used in artificial joints. Titanium and its alloys have excellent corrosion resistance while possessing low wear resistance. The materials used were pure titanium and Ti-6Al-4V alloy. The texturing of the specimen surface was achieved by applying parallel, 1 mm deep grooves at several pitches. Friction and corrosion tests were performed in physiological saline. The textured specimens maintained corrosion resistance. An improvement in abrasion resistance was seen as the pitch of the parallel grooves was reduced. The wear properties were also improved by reducing the pitch of the parallel grooves. However, the wear properties of the textured surface were lower than those of the flat surface. These results indicate that the design of the texturing should be examined to improve the wear characteristics. Therefore, new coating and cladding technology Micro Spark Coating (MSC) was noticed. This coating is high in the hardness and wear resistance. In addition, craters by the electric discharge pulse were formed on the surface. The wear resistance of the coating surface was high. It is planned to carry out the experiment in MSC surface in order to evaluate a fluid lubrication state.

Metalic Glass, Free Volume Model, Impact Fracture, Shear Bands, Strain Rate DependencThe yield behavior of amorphous metals including the metallic glass shows intrinsic dependence on the hydrostatic stress, so that yield criterion models such as Mohr-Coulomb and Drucker-Prager are often used. Both the models can explain the asymmetry in the yield stress under uniaxial compression and tension loading conditions, however, the asymmetric angle of fracture surface is not able to determine based on any theoretical foundation. The free volume model is able to provide that foundation. Shibutani et al. proposed a new constitutive model for amorphous metals derived from some advanced free volume models and the flow rule using the Drucker-Prager yield function as a plastic potential and investigated the yield curves and the formation of localized shear bands with that model using the implicit static FEM code. In this study, the impact fracture of metallic glass was examined by implementing their constitutive model in the explicit dynamic FEM code DYNA3D with laying emphasis on the occurrence mechanism of the asymmetric angle of fracture surface and the strain rate dependence.

On a cleaning of dental implant, a conventional abrasive blasting to remove dental biofilm has a possible influence to increase surface roughness of titanium abutment. So we have developed new cleaning method that the agar particle can be blasted by air blasting to remove the biofilm without the influence to titanium surface. Three types particle (Agar, Calcium carbonate, Calcium phosphate) were used. Test piece (JIS TYPE2 pure titanium) was rectangle. Initial surface roughness Ra was approximately 0.050μm. Air blasting was performed for 5, 10 s at 20mm distance from test piece. Air pressure was 0.2MPa, particle feed rate was 5g/s. Then permanent marker had been painted on the test piece as simulated tooth staining. Ra had large increased when calcium carbonate and calcium phosphate particle were blasted. There was little change in surface roughness when agar particle was blasted. Ra (agar) indicated 0.068μm. Then the glossiness had decreased a little and the condition of mirror-like surface was able to be maintained almost when agar particle was blasted. In all particle, the paint was peeled from test piece, the capability of cleaning was confirmed. There was little change in surface roughness when agar particle was blasted. Also, the capability of cleaning with agar particle was confirmed. In addition, it is thought that the influence of agar particle on natural tooth is a very small. Therefore, it is thought that development of the new professional mechanical tooth cleaning method using the agar particle is profitable.

The Co-Cr-Mo alloy is used for a prosthetic slide part to be superior in wear resistance. The custom-made medical application is examined for the Quality Of Life (QOL) improvement of the person with skeletal system medical care disease. Therefore, the Electron Beam Melting (EBM) that a little and free shape can manufacture is effective for the production of custom-made devices. However, crystal structures are different for the molding position. The end samples (No.5) had short fatigue life. On the other hand, the center samples had long fatigue life. This depends on crystal structure. This is because the central samples has γ phase and the end samples has ε phase. Thus, γ phase influences in improvement of the fatigue life. Therefore I thought that crystal structure is changed γ phase by the heat-treatment. EBM sample was performed heart-treatment (change the ε phase) and reverse transformation heart-treatment (change the γ phase).I performed a hardness examination afterwards. As a result, all specimens became the hardness of the equal degree. The hardness decreased in comparison with before heat-treatment. Thus, I was able to become a γ phase.

Recently, the application of custom-made implant which can fit to the skeleton and the bony substance of the patient is requested. Then, the way of making custom-made implant by additive manufacturing (AM) is remarked. In this study, we evaluated the torsional fatigue property of Ti-6Al-4V alloy made by electron beam melting (EBM) which is one of AM. The microstructure, analyzed by SEM, consists in fine α+β phase. The higher this observation position of EBM product is, the finer this microstructure is because of keeping more heat of dissolution at the bottom. From the result of torsional fatigue test and the fracture surface observation, it was revealed that the EBM specimens have two types of fracture surface morphology. In the case of one fracture surface, when the internal defects influence the crack initiation, the number of cycle to failure is approximately equal regardless of the build position. On the other hand, in the case of another fracture surface, when the internal defects don't influence the crack initiation, a trend is seen in that the number of cycle to failure decreases upper, middle and bottom specimens in that order.

We consider an elastic contact problem for indentation test of layer-substrate body. An elastic layer assumed to be perfectly bonded to an elastic semi-infinite substrate. This problem called Boussinesq's problem which is axisymmetric mixed boundary value problem in elasticity theory. The elastic layer is smoothly indented by a flat-ended cylindrical and spherical indenter. The analytical solutions are obtained by solving an infinite system of simultaneous equations using the method of expressing a normal contact stress at the upper surface of the elastic layer as an appropriate series. Convergence can be achieved using less than 10 terms of the series. The accuracy of values of present numerical results is verified by comparing the dimensionless axial load of present results with results of some previous literatures. Additionally, this paper presents not only distribution of the dimensionless normal contact stress under cylindrical and spherical indenters but also distribution of the dimensionless normal displacement at the upper surface of the elastic layer. Numerical results are given for several combinations of the ratio of shear modulus, Poisson's ratio of elastic layer and substrate and the thickness of elastic layer. These results may establish the foundation for indentation test of layer-substrate composite and provide guideline for design of mechanical property of layered materials.

Soldering is essential technique for assembly of parts of cars, devices, IC’s, and so on. The main component of solder is tin. We electrochemically analyzed the oxidation rate of tin because the oxide thickness affects the strength of oxide film on tin surface. The thickness were measured with TEM, SERA, and AES. The film layer order is SnO/ SnO₂/Sn. Though equilibrium phase diagrams shows that SnO₂ is the most stable state at the exposure condition, SnO was formed. The reduction of tin oxide at NaCl solution is carried out in order to improve the wettability. Tin oxide was reduced about 1nm. Then, pitting was occurred and the wettability of Tin is improved.

Fine particle peening (FPP) using hydroxyapatite (HAp) shot particles was introduced to form the HAp surface layer and improve both the fatigue properties and osteoconductivity of biomedical titanium alloy (Ti-29Nb-13Ta-4.6Zr: TNTZ) with low Young’s modulus. The surface microstructure of the FPP-treated specimens was characterized using a micro-Vickers hardness tester, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and X-ray diffraction (XRD). FPP could form a HAp layer on the surface of TNTZ alloy within a relatively short time by HAp shot particle transfer. Four-point bending fatigue tests were performed at a stress ratio of 0.1 in air at room temperature to examine the effect of FPP using HAp shot particles on the fatigue properties of TNTZ alloy. It was found that the fatigue limit and fatigue life for the FPP-treated specimen were higher than that for the un-peened specimen. This was because FPP increased the hardness of TNTZ alloy at the treated surface.

View of improvement of Quality of life (QOL) for senior citizens, implant treatment that embed prosthesis into a living body has advanced as a method of treating for deterioration or a lesion part. Recently, addition of Hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂, HAp) coatings onto titanium alloy has been developed to reduce duration of treatment and improve strength of treated part. However, adhesion property between such coatings / substrates isn't well known. The purpose of this study is to establish evaluation method of adhesion property for such coatings system. In this study, plasma-sprayed HAp coating specimens that subjected some machining process were prepared. Adhesion strength of these specimens was investigated by using tensile adhesion strength test. The influence of post heat treatment on adhesion strength was discussed, through evaluation of both mechanical properties of HAp coating and tensile adhesion strength between HAp coatings and titanium alloy substrates.

We have been investigating how to use protists as living micromachines by controlling their behaviors using their taxes. Previously we succeeded to transport an object, to assemble simple mechanical parts and to drive micro seesaw by the force of Euglena group gathered around the position controlled blue laser beam. The generation mechanism of Euglena group, however, is still unknown since the group formation was only seen in the high cell density culture solution and in the low density culture, Euglena did not gather or it took very long time to form the group. It means that the behaviors of the individual Euglena in the high cell density culture did not equal to that in low cell density condition. In this paper, we develop an analyzing program of every Euglena's moving traces even in the high cell density condition. The results showed that it needs laser irradiation experience for Euglena to gather around the laser beam. It was clearly confirmed by the experiments of the Euglena's reaction to the moving laser. In this case, only the Euglena behind the laser move to the laser beam. This fact gives an explanation why Euglena does not gather or needs very long time to gather in the low cell density condition. It is that the laser irradiation probability to each cell is very low in the low cell density culture condition.

Polyvinyl alcohol hydrogel (PVA-H) is proposed as a candidate material for cartilage of an artificial joint. PVA-H is expected to achieve the fluid film lubrication by the squeeze film. On the other hand, there are rarely studies about when the squeeze film formed and how effective the squeeze film was. The purpose of this study is to observe the formation of squeeze film between PVA-H and glass surface. In this study, contact area between the PVA-H and glass was observed by using total internal reflection method simultaneously with the measurement of friction force. A repeated loading-unloading mechanism so as to reproduce natural synovial joint was adopted in this study.

The reduction of tissue reactions in an artificial joint composed of an ultra-high molecular weight polyethylene sliding on a Co-Cr-Mo alloy, was investigated. To control the specific wear rate and morphological features of wear debris of the polyethylene, micro slurry-jet erosion was used as a precision machining method for the bearing surface of a Co-Cr-Mo alloy. This method constitutes a type of wet blasting technique, which uses alumina particles as an abrasive medium, along with compressed air and water, to create textured surfaces. Pin-on-disc wear tests, involving multidirectional sliding motion, resulted in a decrease in the polyethylene wear and changes in the morphological features. Primary human peripheral blood mononuclear phagocytes were incubated with the debris, and the wear debris generated on the textured surface changed the secretion of the IL-6 proinflammatory cytokines. We concluded that appropriate surface geometry contributed to prolong the service life of artificial joints.

Shaft seals for waterproof are essential machine elements to enlarge the service life of water pumps or other mechanical products used in wet condition. There is a demand for shaft seals of water pumps used for cooling and circulation of semiconductors. Such shaft seals need high durability at high speed rotation. In this study, new shaft seal using hydrated materials has developed and conducted pressure resistant test to confirm low friction and durability. The results showed that low friction characteristics of the new shaft seal weren't susceptible to water pressure and suggested that performances of the hydrated seal lip were influenced by additives contained in water solution.

To improve life spans of hip prosthesis, it is necessary to solve tribological problem such as wear and loosening. For this purpose, artificial articular cartilage is required which is similar to natural articluar cartilage in structure and functions. In this study, PVA (polyvinylalcohol) hydrogel was used as artificial cartilage in hip prosthesis. Friction property of PVA hydrogel layer as artificial cartilage under walking condition was examined with hip joint simulator. In this simulator, CoCrMo femoral head was fixed to a swinging shaft, and acetabular component with PVA hydrogel layer was mounted on the cradle. Then, the femoral head was moved on PVA liner by PC controlled servomotor while static or dynamic joint load was imposed by hydraulic actuator. Friction force between the femoral head and PVA liner was monitored by a load cell connected to the cradle. As a result, the hip joint model consists of CoCrMo femoral head and PVA liner showed time-dependent frictional behavior and the friction coefficient increased with the progress of the test. The increasing rate of the friction coefficient was depended on the joint load pattern and the inner diameter of PVA liner.

In this paper, non-cryopreservation method for killifish eggs was conducted. It is known that cells become low activity at low temperature, and also freezing point depresses to -20°C under high hydrostatic pressure of 200MPa. Thus, it is expected that cells can be preserved without damage by ice crystal by applying high hydrostatic pressure. In order to verify this phenomenon, the authors developed an experimental device that can conduct in-situ observation of living cells in a high hydrostatic pressure chamber. Using this device, pressuring and cooling experiments for killifish eggs were conducted. As a result, the authors found that the pressuring and cooling path affected on the survival rate of the killifish eggs. Cooling before pressuring path have a higher survival rate than pressuring before cooling path. This is because the eggs become low activity in low temperature, and the damage caused by pressuring become small.

Vascular structure for oxygen and nutrient supply is required for creating three-dimensional structuring tissue and organ in vitro. This paper presents tissue formation of vascular endothelial cell network and myoblast cells using gel micromachining technique. The alginate gel was used as noncytotoxic material that inhibits adhesion of cells. The alginate gel was formed on a glass plate by spin-coating. The alginate gel pattern was created by wet etching or lift-off process along the pattern of photoresist. The alginate gel pattern was able to be formed by wet etching with dimension of more than 50 μm. The interval between the alginate gels pattern was able to be formed by lift-off with a dimension of more than 10 μm. The formations of cell pattern were created along the gel pattern. After removing the gel pattern by alginate lyase, new cells adhered to the removed section. With these processes, the vascular endothelial cell and myoblast cell pattern was achieved.

Surfaces of lotus leaf and moth eye have fine structures. The structure produces water repellent effect or reflection suppression. The purpose of this study is to reproduce these characteristic to the artificial material surface by using a precision machining method. Micro slurry-jet erosion has been proposed as the precision machining method for a glass or plastic surface. The micro slurry-jet erosion method is a wet blasting technique which used alumina particles as the abrasive medium along with compressed air and water to create the fine structures. The glass surface processed has a hydrophobic character and do not show influence of the light transmission property. These results concluded that the precision machining method was one of the promising method to create the bio-inspired surface on the artificial materials.

Evaluation of cell traction forces is crucial to biological researches. Accordingly, a number of cell traction forces evaluation techniques have been proposed in the past. In contrast to extensive studies on effects of exogenous forces such as tensile stretches and fluid shear stresses, there has been less work on how endogenous contractile forces are generated within cells under various conditions. This may be partly attributed to a lack of experimental techniques for evaluating the cell traction forces. One of the most popular techniques is traction force microscopy (TFM) using fluorescent microbeads embedded within hydrogels on which cells are plated. The cell traction forces are usually estimated from displacement of fluorescent beads and the physical properties of the hydrogel. This technique requires complicated image correlation analyses and sophisticated experimental skills. Hence, it is not practical to use such a technique in large-scale screening programs. An alternative has been developed, which makes it possible to visualize the cell traction forces using a gold ultra-thin film.

In this study, we have developed a novel microfluidic device to control a local chemical stimulation area in cell culture spaces toward cell-based assays. The device consists of a cell culture channel and microfluidic probe (MFP) channels which are possible to control chemical stimulation area. The device has been evaluated by a fluidic simulation using Finite Element Method (FEM) and a flow control experiments. The stimulation areas using the device were evaluated by fluidic simulation and controlling the flow ratio of the injection/suction. The results showed that precision control of stimulation area was possible by regulating the flow ratio, as well as the simulation. In addition, cell staining experiment was demonstrated to confirm potential of the device. As a result, only cells nearby tiny chemical stimulation area indicated by the fluidic simulation result were stained by the proposed method. We conclude that the proposed device can be a powerful tool for biological applications such as the differentiation control of pluripotent stem cells and other cells signaling studies.

In biomedical and bioengineering fields, it is important to evaluate surface information such as the surface composition, morphology and structure of biomaterials for realization of the best cell engraftment between an implanted biomaterial and a cell. Wetting phenomena are an important indicator in evaluating a solid's surface properties. However, at the present time, there are no adequate and reasonable methods to evaluate the solid surface property for the cell engraftment from a viewpoint of wetting phenomenon. In the present study, the wetting behavior of droplets on solid biomaterials is experimentally observed. Then, osteoblast cells are cultivated on the solid biomaterials to measure the amount of the cells adhering to the solid surfaces. The results are evaluated on the basis of a new wettability model that considers the adhesion energy in the horizontal and vertical directions in addition to the gravitational potential of the droplet. Then, the possibility of a surface evaluation method based on the new wettability model is considered.

During wound healing process, dermal fibroblasts generate a contraction force stimulating cell infiltration and collagen secretion to accelerate the wound healing process as well as decreasing the surface area of the wound. The disorder of this contraction force has risks to cause a skin disease called “keloid” by excessive cell proliferation and secretion of collagen. Keloid is sometimes accompanied with severe itchiness and pain. However, there are not any ideal treatment methods because the occurrence mechanism has been still unclear. Therefore, it is important to monitor the contraction force during wound healing process and to evaluate the effect of several growth factors working in the healing process on this force. Usually, the dermis tissue is reconstructed by embedding the fibroblasts in collagen gel and cultured in vitro. This dermis tissue model would contract during in vitro culture to simulate the wound contraction phenomena under the healing process. In this study, we developed the culturing device for dermis tissue model to enable monitoring the contraction force. This device allowed the culture of dermis tissue model by simulating the condition of CO₂ incubator using the glass heater and gas controller. The effects of ascorbic acid, FGF-2 and cell concentration on contraction process were evaluated using this device. As the results, it was suggested that some growth factors were related to contraction process in three-dimensional dermis tissue model.

Experiments were conducted for air-water two-phase flow using a horizontal rectangular mini-channel having hydraulic diameter of D_H = 3.2 mm. In order to know the effects of the channel wall surface wettability on the two-phase flows, the wettability on the test section was changed by coating the hydrophobic agent. The contact angles, θ_a, were approximately 80° for the wall surface without coating and 115° for one with coating. In the present experiments, flow pattern, bubble length and pressure drop were measured. The experimental results for coating and non-coating cases were compared each other. From the comparison, it found that surface with the coating makes bubbles length longer, and for the coating case the frictional pressure drop is smaller than the non-coating one.

Bone has an ability to adapt itself to its mechanical environment. This adaptive phenomenon is regulated by bone cells such as osteoclasts, osteoblasts, and osteocytes. Osteocytes are believed to sense mechanical stimuli and transmit biochemical information through intercellular communication. Osteocytes are buried in bone matrix and form a 3D network via cell processes. It has been experimentally suggested that the structure of the osteocyte network is related to mechanical environment. It has been found that the osteocyte network has different structures depending on bone specific diseases such as osteoarthritis, osteoporosis, and osteopetrosis. The elucidation of the osteocyte network formation process under mechanical environment is expected to lead to early detection and treatment of bone specific diseases. However, it remains unclear how the osteocyte network is formed. In this study, we aim at clarifying the relationship between osteocytes within bone matrix and their mechanical environment by the morphometry of osteocytes based on fluorescence imaging and the analysis of the bone specific gene expression (Sost/Sclerostin). To measure the morphological characteristics and the orientational direction, we fluorescently stained actin cytoskeleton and nuclei in osteocytes embeded in a murine long bone. As a result, it was shown that the osteocyte cell bodies are elongated along the longitudinal direction of the long bone. Furthermore, we applied the mechanical loading to bone tissue ex vivo with a three-point bending system, and measured the Sost/Sclerostin expression. The result showed that bone tissues ex vivo change the Sost/Sclerostin expression, depending on the mechanical stimuli.

Studies on shape change associated with movement of fibroblasts are mainly based on two-dimensional observation and analysis. Since the movement of fibroblasts is slow and complicated, few analytical studies have focused on three-dimensional cell movement. In this study, we observed three-dimensional shape change associated with movement of fibroblasts. Swiss 3T3 mouse fibroblasts were transiently transfected with TagGFP-lifeact, and actin-labeled cells were placed on a glass substrate coated with 30 μg/mL fibronectin with PBS for 30 minutes. Time-lapse live cell images were obtained by confocal laser scanning microscopy, and cell shape was measured from three-dimensional actin- labeled images. As a result, changes in z-coordinate of volume center (VC) were lowly related to movement of fibroblasts. Moreover, z-coordinate of base area center (BC) steps forward from z-coordinate of VC. Further study would be needed to clarify the reason why the movement of the VC and BC linked based on the molecular dynamics of the intercellular structure.

Intracellular Ca²⁺ wave regulates several signal-transduction pathways. The translocation of Protein kinase C α (PKCα) by pharmacological stimulation occurs with an increase of intercellular Ca²+ concentration. A mechanical stimulation by micropipette also causes a transient rise in intracellular Ca²⁺ concentration and Ca²⁺ wave. However, the relationship beween PKCα and Ca²⁺ wave by mechanical stimulation is not understood well yet. In this study, we observed the change of intracellular PKCα distribution and intracellular calcium concentration simultaneously in Bovine Aortic Endothelial Cells (BAECs) by a mechanical stimulus. And, we investigated the relationship between PKCα distribution change and inflow of Calcium ion through Stretch Activated (SA) Channels. Mechanical stimulation induced a rapid Ca²⁺ wave and PKCα translocation to the stimulated region. Fluorescence of PKCα reached peak in around 20 sec after stimulation. When Calcium biding domein of PKCα was inhibited and when the SA channel was inhibited, PKCα translocation was not observed. Moreover, when Ca²⁺ in the extracellular medium was chelated by EGTA, PKCα translocation was not observed. On the other hand, PKCα translocation was observed even though endoplasmic reticulum Ca²⁺ was inhibited. These results suggested that extracellular Ca²⁺ through SA Channels is necessary to PKCα translocation by mechanical stimulation.

Acute subdural hematoma (ASDH) is a type of head injury which occurs frequently in the traffic accidents. Although ASDH can be caused by the rupture of the bridging vein induced by the rotational head motion, the detail mechanism has not been clear yet. Therefore, to clarify the mechanism, various studies were conducted by using the simulation and the physical models. In the previous study we carried out, the physical model with the intracranial structure was developed as a novel anthropometric test dummy (ATD) head, however, there is still a challenge in the measurement method of the intracranial brain motion which uses multiple high speed cameras. For the practical application of the new ATD head, it is required to improve the measurement method. In this study, direct evaluation method of the intracranial brain motion without high-speed cameras was developed. A 6DOF motion sensor was implanted in the brain model and the intracranial brain motion were calculated by using Rodrigues' rotation formula. For the validation of this method, the occipital impact experiment was carried out and followed by the sled test for the evaluation under the traffic accident condition. The results showed that the risk of ASDH can be evaluated by relative motion between the skull and brain of the ATD head calculated by using the developed method.

In this research was development and validation of the elderly head FE model for the purpose of elucidating the effect of brain atrophy of elderly on the head trauma. Head model for impact analysis was to reproduce the atrophy of the 80-year-old brain tissue on the basis of the head shape of 20s. Impact simulation using the constructed head model of the young and elderly, described the verification of head model and the effect of intracranial response in elderly.

Diffuse brain injury is classified by coma time clinically. If coma time is less than 6 hour, it is called concussion, and if coma time is 6 hour or more, it is called Diffuse Axonal Injury (DAI), but the difference of occurrence mechanism of these two injury in neural scale has not been understood yet. Therefore, it is needed to clarify relationship between deformation of brain parenchyma and tolerance of brain function. Although electrophysiological change of axonal function is important, various studies have been conducted based on morphological change of axon. The purpose of this study is to examine relationship between strain distribution and action potential when strain is loaded to corpus callosum of rat brain slice. Firstly, we measured action potential transmitting across corpus callosum when static strain or dynamic strain is loaded. Then we constructed finite element model of rat brain slice to reconstruct strain distribution of the experiment. As a result, we found that action potential is decreased significantly when static strain 0.1 to 0.2 is loaded. And decrease of potential is also observed when dynamic strain was loaded.

The purpose of this study is to make thoracoabdominal tolerance during the crowd accident. A healthy female subject underwent loading to chest 20 kg and loading to abdominal 0 kg, 10 kg and 20 kg. Subject also measured vital capacity, tidal volume and thoracoabdominal displacement. As a result, the thoracoabdominal displacement showed a tendency to change same as lung capacity and tidal volume. As for the thoracoabdominal displacement is suggested that an index of tolerance for suffocation during crowd accident.

For comprehensive quantitative estimation of falling injury risks, it is important to divide the injured time into fall trigger, protective reaction, and passive deformation of body tissue. However, the mechanism of fall trigger has not been clear. Therefore, we constructed fall trigger detection method based on analysis of some falls of infants captured in living environments. In analysis, we acquired fall motion data by using a motion capture system, and evaluated fall trigger using Center Of Pressure on BOS coordinates and foot angle (Roll, Pitch, and Yaw). As specific changes of time courses of the parameters were observed near the fall start time, these parameters can be related to fall trigger. In addition, we detected the fall trigger using the change point detection in falls by the sliding. As a result, we detected fall trigger all three falls by the sliding. The method is useful for the detection of the fall trigger in the fall by the sliding.

To investigate the cause of the change of arithmetic mean roughness R_a and arithmetic mean waviness W_a of austenitic stainless steel under low-cycle fatigue loading, precise observation focusing on slip bands and grain deformations was conducted on SUS316NG. During the fatigue tests, the specimen's surface topography was regularly measured using a laser microscope. The surface topographies obtained were analyzed by frequency analysis to separate the surface relief due to persistent slip bands from that due to crystal grain deformation. The height caused by persistent slip bands and that by crystal grain deformation were measured respectively. As a result, the both heights in initial stage of usage factor (UF) more developed compared with those in later stage of UF. The amount of increase in the heights with respect to UF increased with strain range. The trend of development of both heights was similar with the trend of R_a and W_a.

The purpose of this study is to investigate low cycle fatigue (LCF) and high cycle fatigue (HCF) strength, crack initiation and growth behavior of Ni based castalloy 246. LCF and HCF tests are conducted under load controlled conditions. As the result of the observation of etched specimen, grain size is from 3 mm to 5 mm. And microstructure is composed of dendritic structure. Growth orientation of dendritic structure varies in every grains. The results of LCF test show that small cracks initiate at the first cycle, followed by the crack growth along slip direction. Observation of fracture surface reveals that small cracks are originated at casting defect or dendritic boundary. The results of HCF, on the other hand, show that small crack initiates from subsurface casting defect under Δσ ≦ 600 MPa, while under Δσ > 600 MPa, fracture origin becomes surface. As the result of EBSD, crack growth direction is along slip plane.