Intermittent claudication is a gait disorder due to peripheral arterial disease (PAD) and lumber spinal canal stenosis (LSS). The purpose of this study is to identify the pathogenesis of intermittent claudication with a simple and minimally invasive measurement system, for the purpose disease-specific factors are extracted. However, the obtained results are limited since only uni-angle was considered. This paper estimates the length of the biarticular muscle to derive new factors for differentiation. We will create a two-dimensional muscle model from anatomical model and drawings, length data of biarticular muscle was calculated by substituting the time series of measurement data to this. We were able to find a significant difference in maximally expanded and maximally relaxed muscle length and motion range which was calculated from the measured data.

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The objective of this study was to clarify the optimal form of walking in water for the patients of knee osteoarthritis. By our developed simulation model SWUM, joint torques and joint forces in the lower limb considering the fluid force in sagittal plane were calculated. From joint torques calculated by SWUM, the muscle forces in the lower limb were calculated using a two-dimensional musculoskeletal model. In addition, the knee joint force considering the muscle tension was calculated as the sum of the knee joint force calculated by SWUM and muscle forces. By maximizing the exertion of quadriceps under the constraint of the knee joint force, we obtained the optimal walking form in water for the patients of knee osteoarthritis. The optimal form had that flexing the hip and knee joints in latter half of the swing phase. By flexing the hip and knee joints simultaneously, fluid drag acting on the lower limb was reduced. This helped to reduce the knee joint force.

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Research and development of Micro air vehicles (MAVs) with a maximal dimension less than 15 cm have been a very hot topic in the last decade. MAVs are desired to be capable of performing missions such as environmental monitoring, surveillance, and assessment in dangerous environments. Currently most Bio-inspired MAVs have four wings, while many insects and birds can fly by two wings. In this study, especially focusing on the wing structure and in-flight deformation of flapping wings, we evaluated the aerodynamic performance of single flapping wing which has a semi-elliptic planform and is made of a polyethylene film, a carbon rod at leading edge and aluminum rod at wing base. The mean thrust forces by the flapping wings were measured by attaching the wings onto the newly developed measurement system. The aerodynamic performances of the flapping wings in terms of flexible wing kinematics and vortex structures and their relationship with aerodynamic force generation were further investigated by combining the reconstruction of three-dimensional wing kinematics and the computational fluid dynamic (CFD) method. The flexible wing kinematics, and the force generation by flexible flapping wings accordingly, was found to be strongly affected by the flapping frequency, wing beat amplitude and wing structure which suggest that the optimum wing structure for flapping MAV is dependent on the wing kinematics at wing base.

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In this study we investigated the effect of wing deformation on numerical simulation of aerodynamics of ornithopters. The ornithopter we used had a pair of wings and a tail wing, and is capable to perform forward flight. The wing consisted of a rigid leading edge bars and a polymer film membrane. We measured the wing deformation with three high-speed video cameras in three different conditions: free flight, tethered flight, and "semi-tethered flight" in which the ornithopter was mounted on a linear actuator and moved forward constantly. Then, measured wing deformations were applied to a CFD (Computational Fluid Dynamics)-based simulation in which the ornithopter was fixed in a steady flow. As a result, the wing deformation measured in the free flight and the semi-tethered cases caused larger vertical force than that with the wing deformation of the tethered case. It was also found that the wing deformation of the free flight case resulted in smaller horizontal force than that of the the other cases at the latter half of downstroke. On the contrary, at the middle of upstroke, the wing deformation of the free flight case caused larger drag than that of the other cases. These results suggest that it is desirable to use a free flight model when time variation of aerodynamic forces is considered.

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Natural flyers utilize unsteady mechanisms for generation of a fluid force. Wake capture and rapid pitch rotation were focused on unsteady mechanisms of a flapping wing in this study. The purpose of this study is to measure the fluid force of the unsteady mechanisms of the flapping wing in hovering. The length and a flapping frequency of the model were decided by using Reynolds number and non-dimensional frequency of Hawkmoth. The model wing was constructed of aluminum. Flapping motion was controlled by two servo motors. Result of experiment, lift generation by wake capture was confirmed in translational and turning motion. However, the lift generation by wake capture was not confirmed in sinusoidal motion. The lift generation by rapid pitch rotation was not confirmed in sinusoidal motion and translation and turning motion.

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This paper concerned with the relationship between the body structure and the locomotive functions of springtail. The jumping movements of springtails from the inside of the bubble at the air-water interface were analyzed from high-speed sequences of images captured at rate of 4500 frames per second. The results of an experiment aimed at elucidating the jumping mechanisms of water-floating springtails are described. The variation of vertical velocity during the springtail jump was analyzed. The microscopic structure of body was also clarified by a laser scanning microscope. The effect of drag reduction during the movements of springtail in the air was discussed with the analysis of jumping motion from the view point of hydrodynamics and microscopic observation of the structure on the body surface.

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In this study, opossum shrimps were introduced to elucidate propulsion mechanism of small aquatic creatures by ciliated pleopods. A pleopod was simplified to a straight cylindrical stem of 1.0mm in length and 0.1mm in diameter with 10 much narrower cylinders perpendicularly projecting on its either side to mimic the cilia. Flow resistance acting on the pleopod in a uniform flow, which corresponds to the propulsion force in rowing it, was computed, and it was found that the resistance decreased when interval between the adjacent cilia was below 0.4 mm.

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Microbe can move smoothly in water environment with high efficiency, which could offer new ideas for future micro machines. In this study, we investigated the spiral moving behavior of flagellum by using Stoke's theory and experimental models. We simulated euglena's fluid environment of Re number of 10^<-4>. The optimal spiral shapes in terms of propulsive efficiency and the comparison with Stoke's theory were studied. The propulsive efficiency was found to be highest when the spiral diameter was 15mm or 20mm as a result of the tradeoff between torque and propulsive force. From real motion of euglena, the drag force the body receives was estimated and converted to the value what the model experiment gave as propulsion force. We found that the model experiment gave enough and meaningful force to drive the whole body.

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In this study, we tried to make an object transportation system using Daphnia magna. We developed a target object for transportation experiment. We used 5mm diameter transparent acrylic rod and the lower part was bored. A black film and a small white ball were attached on the top surface of the object to improve the contrast to ease the position detection in the image processing. In the case if the Daphnia does not contact to the object, (1) Daphnia was first guided to the guide point where the distance is about 10mm opposite the aiming transportation direction. (2) Then, Daphnia is controlled to collide with the object. (3) If Daphnia did not collide to the object, then Daphnia is guided to the evasion point located at 5mm side of the object, then controlled to the guidance point again, and repeat the scheme. When Daphnia is contacting to the object, the lighted direction is compensated to the outside of the target course to transport the object on the guidance route. The compensation angle was calculated by the proportional control method. By using this control scheme, a Daphnia can transport an object through the 7 apex (about 1.5 laps) of the star-shaped target routes.

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Antifreeze proteins (AFPs) and several synthetic polymers are known as anti-ice nuclei (anti-IN), which inactivate ice nuclei (IN) in water and thus inhibit heterogeneous ice nucleation catalyzed by IN. Recently, it has been found that several types of polyphenol compounds also inhibit heterogeneous ice nucleation. In this study, ice nucleation catalyzed by silver iodide (Agl) particles, which are typical inorganic IN, in emulsified solutions of five different polyphenol compounds (a-oligoglucosyl quercetin 3-O-β-D-glucopyranoside (Q3(Glc)n), epigallocatechin gallate (EGCG), tea catechin, tannic acid, and oligonol) was investigated experimentally. Results showed that the ice nucleating activity of Agl was inactivated by all the polyphenols used here. For Q3(Glc)n and EGCG solutions, in the majority of the emulsified droplets, ice nucleation occurred within a narrow temperature range between -17 and -20℃. On the contrary, for tea catechin, tannic acid, and oligonol solutions, ice nucleation occurred within relatively wide temperature range between -17 and -38 ℃. The highest ice nucleation temperatures in the emulsified droplets of the polyphenol solutions were considerably lower than those of AFP and synthetic polymer solutions. Especially, the highest ice nucleation temperature for oligonol solution was -19.4 ℃. Such anti-ice nucleating activities of the polyphenols available at relatively high temperatures would be promising for practical applications in various fields.

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chloride or calcium chloride to understand the behavior of cations (sodium, potassium, calcium) near the ice wall. The dynamics of three cations are compared by using the mean square displacement and radial distribution. Also, The dynamics of a cation near the ice wall are compared with those of a cation far from the ice wall using mean square displacement and radial distribution function. It is found that strong hydration shells caused by the calcium ions are not affected by the other ions and water molecular around the shells. The second finding is that the mean square displacement of the cations near the ice wall is lower than that of the cations far from ice wall. Also, the ice wall is found not to affect the hydration shells.

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A method to actively enhancing supercooling is one of most promising techniques for cryopreservation. The object of this paper is to study the effects of alternating magnetic field on supercooling of water. In the experiments, water or 0.85wt% NaCl solution in a glass tube with thermocouple was cooled at constant cooling rate, with magnetic field. Two types of magnetic field; (a)static magnetic field and (b)alternating magnetic field, were tested by varying magnetic flux density and frequency. Regarding the case of static magnetic field, no supercooling enhancement was found. On the other hand, as for alternating magnetic field, weak enhancement of supercooling was found at magnetic flux of 0.2mT. Furthermore, for 0.85wt% NaCl solution, it was suggested that there is optimum value of frequency for enhancing supercooling degree.

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We have conducted laboratory experiments of solidification on a cooling vertical cylinder in a hypoeutectic sodium nitrate solution that fills rectangular vessel, and formulated one-dimensional model for predicting the vertically averaged solid layer thickness. The experiments have been carried out by heating the lower wall of the vessel and cooling the vertical cylinder. Stratified concentration layers are formed in the vessel with the growth of solid due to the solute emission. As the process advances, the solution is eventually divided into two layers with a large density difference. The two layers have different average temperatures and concentrations. Taking the presence of the two layers into consideration, we have formulated the one-dimensional model for the growth of solid layer. The theoretical predictions compares well with the experimental results.

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In cryopreservation of cells, the bell-shaped cell survival curve with an optimal cooling rate is understood on the basis of two-factor hypothesis, i.e. extracellular freezing injury without intracellular freezing and intracellular freezing injuries. Mathematical description and prediction of the cell survival curve is one of important subjects in the area of cryobiology. The intracellular freezing injury was already modeled successfully and mathematically based on intracellular ice formation. In the present study, a mathematical model with reaction kinetic formulation was newly proposed and developed to describe the extracellular freezing injury, i.e. slow-freezing injury. A parameter study of model constants was performed to evaluate the cells survival rate as a function cooling rate. The model constants were also determined by inverse problem analysis based on the experiment with human erythrocytes and monocytes. The experiment and prediction by the model were compared on the cell survival curve. The result shows that the extracellular freezing-induced cell death is successfully described by the reaction kinetic mode in this study.

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In cryobiology, the freezing of cells and tissues requires further detailed study to clarify the mechanisms of freezing injury and protection by cryoprotectants, and to extend the application of cryosurgery and cryopreservation. Generally, the freezing and thawing behavior of cells depends on the properties of the cells. The freezing of mature neurons has largely been neglected, despite the fact that freezing these cells is useful for the efficient preparation of experimental materials in medicine/poison screening and other neuroscience research. The freezing of mature neurons is also very attractive for studying cell morphology because of their characteristic long, thread-like neurites extending from the cell body. The present study analyzed changes in cell morphology and cytoskeleton to show the influence of cooling rate and attained minimum temperature during cooling.

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In order to improve various thermal therapies quantitatively, blood perfusion rate in living tissue was estimated by measuring heat flux, and its temperature dependency was evaluated. The abdominal heating controller was used for heating. A heat flux sensor was installed between the heating disk of the abdominal heating controller and abdominal area. The time variation of heat flux and surface temperature were recorded by data logger. By measuring four subjects, the positive correlation between the heat flux and surface temperature was confirmed. The analytical relationship the among heat flux, surface temperature and blood perfusion rate were derived by using analytical solution of 1 -D bioheat transfer equation. According to this relationship, blood perfusion rate of each subject was estimated. As well as the heat flux, blood perfusion rate had positive correlation to surface temperature, namely temperature dependency of blood perfusion rate.

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The pulse diagnosis is one of medical techniques in the traditional Chinese medicine. In the pulse diagnosis, a doctor put fingers onto radial artery of a patient and diagnoses diseases from the tactile sense of the pulse waves detected by the fingers with various indentation patterns of the artery. This diagnosis is a simple and non-invasive. And it is also said to be able to detect decline of the health. We have developed one dimensional mathematical model of arterial blood flow in an arm to reproduce the indentation of the radial artery by a finger, expecting essence of the diagnosis is in the change of the pulse waves by the indentation. This model takes into consideration bifurcation and reconnection of radial and ulnar arteries. In this research, we modified this model to quantitatively reproduce reflection of pressure waves at the bifurcation and reconnection, and it was verified by comparing the numerical result with analytical solution derived from characteristic impedance of the arteries.

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Cell manipulation with fluid flow is recently combined with optical tweezers for further precise manipulations. In that combined manipulation system, variety of cell types are manipulated, including yeast cells and stem cells. Although that combined systems allow variety of cells to be positioned precisely, laser power should be limited because of optical toxicity. In this study, minimum laser intensities which is required for trapping red blood cells were evaluated.

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The AC electric field driven manipulation of suspensions becomes one of the major techniques in micro- and nano-devices in the field of biotechnology. In the present study, experimental and numerical studies of cells suspensions in a uniform high frequency AC electric field have been performed to explore the mechanism of the evolution of aggregation and clustering of cells under the exposure of the uniform high frequency AC electric field. In the uniform AC electric field, only forces of dipole-dipole attractive/repulsive interactions present between cells. This behavior of dielectric particles in the uniform AC field, which is differ from that in the non-uniform field, is markedly advantageous in applying DEP technology to positioning of particles in a suspension. Suspensions of HeLa cells in 10% sucrose solutions were used for the experiment while the method of molecular dynamics (MD) was employed to analyze the problem numerically. A theoretical model to compute the trajectories of individual cells under the action of dielectrophoretic (DEP), dipolar interparticle, viscous, and gravitational forces was newly developed. Results demonstrated that the cells began to aggregate locally depending on field frequency. In the present experiment, the lowest field frequency, 10 Hz, used in the experiment was found to effectively aggregate cells.

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Culturing embryonic stem (ES) cells effectively requires feeder cell layer. However, to apply the ES cells in a clinical setting, it is important to get rid of the feeder cells after the expanding culture of ES cells. We focused on dielectrophoresis (DEP) to discriminate the ES cells from the feeder cells. In this study, we hypothesized that DEP forces generated on ES and feeder cells are vary depending on their electric properties. To test this hypothesis, dielectrophoretic properties of ES and feeder cells were measured by custom-made DEP cell analysis chip. From the results, the DEP properties of ES and feeder cells showed different dependencies on the frequency of applied AC-electric field. Using the different frequency-dependencies of the DEP force and a flow-induced shear force, it might be possible to get rid of the feeder cells from ES cell culture.

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High frequency oscillatory ventilation (HFOV) is an artificial respiration technique characterized with a low tidal volume and a high frequency. The present study aims to consider the effects of its ventilation frequency on the gas exchange in respiratory bronchioles. The geometrical model of the respiratory bronchioles was created on basis of Weibel's data. The flow in a dichotomous model was numerically studied with a sinusoidal inflow and flow-compliance-based pressure outlet conditions. The results demonstrated a significant dependency of gas redistribution on the ventilation frequency. Higher frequency of ventilation caused shallower but deeper penetration of an inhaled air from the central part of the airway. The volume of a gas replacement per second, assessed as integration of inwardly penetrated flow, had maximal at the ventilation frequency of 15 Hz. These results suggests the importance of adjustment of ventilation frequency for achieving efficient gas replacement in HFOV.

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This paper presents a sophisticated approach to address a nearly incompressible membrane, based on a pressure-correction approach. Unknown velocities are updated by solving the equation of motion discretized in a step-by-step manner, and the pressure field is determined by solving a discrete Helmholtz equation. In a 2D validation test, it has been confirmed that the present approach is possible to deal with the nearly incompressible membrane without paying attention to numerical instabilities coming from a high stiffness of surface dilation.

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modeling of blood flow in cerebral arteries with aneurysm and stent. These techniques are used in conjunction with the core computational technique, which is the space-time version of the variational multiscale (VMS) method and is called "DST/SST-VMST." The special techniques include using NURBS for the spatial representation of the surface over which the stent mesh is built, mesh generation techniques for both the finite- and zero-thickness representations of the stent, techniques for generating refined layers of mesh near the arterial and stent surfaces, and models for representing double stent. First we compare the flow patterns obtained with the finite- and zero-thickness representations of the stent. We compute the unsteady flow patterns in the aneurysm and investigate how those patterns are influenced by the presence of single and double stents.

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We presented an adherent cell model on a rigid substrate incorporating cytoskeletal orientation based on a minimum energy concept. A spherical cell model was spread on a plane so as to match with a cellular outline obtained from the fluorescence image of a real cell. In the process, we optimized the cytoskeletal element's orientations in the cell model by repeatedly changing it with the simulated annealing algorithm considering morphological characteristics of a real cell. The results demonstrated that a cellular long axis and relationships between the normalized cellular height and surface area in our cell model were in agreement with the real cell data. Also, the distributions and average value of the angle between the cellular long axis and the orientation directions of cytoskeletal elements agreed with our experimental data. In addition, the strain distribution of cytoskeletal elements in the model after spreading corresponded with that of available experimental data.

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We presented an adherent cell model on a rigid substrate incorporating cytoskeletal orientation based on a minimum energy concept. A spherical cell model was spread on a plane so as to match with a cellular outline obtained from the fluorescence image of a real cell. In the process, we optimized the cytoskeletal element's orientations in the cell model by repeatedly changing it with the simulated annealing algorithm considering morphological characteristics of a real cell. The results demonstrated that a cellular long axis and relationships between the normalized cellular height and surface area in our cell model were in agreement with the real cell data. Also, the distributions and average value of the angle between the cellular long axis and the orientation directions of cytoskeletal elements agreed with our experimental data. In addition, the strain distribution of cytoskeletal elements in the model after spreading corresponded with that of available experimental data.

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In the primary process of thrombus formation, platelets adhere to the vessel wall via an interaction between the glycoprotein Iba (GPIba) on a platelet surface and von Willebrand Factor (vWF) A1 domain on damaged vessel wall. The bond between proteins is reversible and has short life-time. In this study, the platelet adhesion on vessel wall was investigated using kinetic Monte Carlo (kMC) simulation for the multiscale simulation scheme of thrombus formation. The kMC lattice model of a platelet surface with GPIba localization region was constructed in consideration of three kinds of events: GPIba diffusion, bond formation and breakage between GPIba and vWFAl. The number of bonds between GPIba and vWFAl and the adhesion force between a platelet and vessel wall were statistically evaluated. The Worm-like Chain (WLC) model, which has the entropic elasticity, was used as the kinetic model of bond between GPIba and vWFAl and compared with the linear spring model.

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In orthodontics medical treatment the diagnostic system which simulates movement of the tooth by orthodontic force is required in order to perform orthodontics medical treatment more easily for a short period of time. In this research, teeth finite element model in consideration of the mechanical property of the periodontal membrane was developed and the simulation procedure of the bone resorption which occurve in an alveolar bone was proposed. As a result, it was ensured that teeth finite element model considering the characteristic of the periodontal membrane was effective. By using a bone resorption simulation procedure, the possibility of representation of the bone resorption in an alveolar bone was sugested.

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Giraffe's long neck is subjected to large moment and under severe mechanical condition. The giraffe's neck is interesting structure in mechanical viewpoint, because it achieve a both of high strength and flexibility. Purpose of this study is to investigate how does giraffe's neck adapts to the severe condition. In this study, we created finite-element models include bone and ligament and muscle on giraffe's neck and analyzed about displacement and stress. In addition we created models represented some postures of drinking water and. We gave muscle force to muscle models by equivalent heat contraction. As a result, we confirmed that the model can keep their posture stably with muscle forces, and cervical bone stress is also under feasible region.

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There are many studies of patient-specific stress analyses of musculoskeletal systems based on x-ray CT images. However, conventional finite element models reported in these researches were composed of the elements which have isotropic material properties in spite of the anisotropy of anatomical bony tissue. It means that more accurate analysis of bone requires a huge amount of tiny elements to represent material anisotropy of bone. This study aims to generate a small FE model of bone with anisotropic material properties in order to perform more reliable stress analyses with a personal computer. This paper proposes quantification algorithm of material anisotropy of bone based on micro-focused CT images. A stress analyses were performed and it reveals the consideration of bone anisotropy is important for patient-specific analysis of bone tissue.

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We developed a computational system that accounts for the combined behavior of cerebral nervous system and musculoskeletal system, aiming to provide a useful tool for investigating the mechanisms underlying motor dysfunctions (e.g., Parkinson's disease) and exploring effective therapeutic approaches. The musculoskeletal system was modeled based on a finite element description of soft-tissues, in which the material behaviour of the muscle is separated into an active part and a passive part. The active part corresponds to muscle activation due to muscle fiber contraction, while the passive part represents the intrinsic mechanical property of muscle. In the description of muscle activation, the motor-unit activity model was introduced to take into account the effects of neural signals on the behaviour of motoneurons. In the model, the motor-unit force of a single muscle fiber is regulated by the number of motor units recruited and their firing rates of the active potential. The developed model system was applied to simulate an isometric muscle contraction behavior. The results showed the inhomogeneous distributions of the activated muscle fibers and motor-unit forces in the three-dimensional model.

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Neural networks for a human motion are investigated towards the unified numerical simulation of brain, neural networks, and three-dimensional musculoskeletal system. A simple model for an arm movement suggests that abnormal motion is caused by the dopamine-depletion in upper central nervous system. More detailed neural networks based on a neuron firing model are also developed towards the integration in the musulo-skeletal model. It is confirmed that the motoneuron model successfully reproduces the recruitment when injected direct current becomes larger.

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We have been applying photomechanical waves (PMWs), which are generated by the irradiation of a laser-absorbing material (target) with nanosecond laser pulses, to gene transfer iv vivo. In this study, we developed an optical-fiber-based gene transfer system for its endoscopic application. A fiber tip with a target film covered with a transparent plastic disk for plasma confinement, by which peak pressure and impulse of PMWs can be increased, was attached to a quartz fiber. The target film was irradiated with nanosecond laser pulses transmitted through the fiber to generate PMWs. Characteristics of PMWs emitted from the fiber tip were examined to confirm the necessary conditions for gene transfer. We then attempted to transfer reporter genes to the rat skin as a test tissue in vivo with the fiber system. The results showed significantly high protein levels and spatially selective pinpoint gene expressions in the tissue.

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Systemic chemotherapy is the most popular therapy, especially for breast cancer metastasis. However, a lymphatic administration method has not been developed due to the absence of useful experimental animal models. We have developed a mouse model of the pressure-driven lymph node metastasis via the afferent lymphatic vessel (LV). We developed a system allowing simultaneous imaging of the FITC flow in LNs, and the pressure measurement inside the LNs of MXH-10 mice. Using this system, we also obtained the FITC flow characteristics through the LV, and investigated the administration induced pressure increase, drug dosage and administration speed to deliver drugs to the axillary lymph node from the inguinal lymph node. This administration method requires less doses to deliver drugs relative to the systemic chemotherapy. These results allow more effective and efficient drug delivery system.

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Growth of most human tumors leads to elevated interstitial fluid pressure (IFP). The mechanisms underlying the high tumor IFP are still not fully understood, but may include increased vascular permeability and abnormal lymph drainage leading to increased fluid volume, followed by elevated IFP. The resultant IFP may lead to poor and heterogeneous uptake of macromolecular and nanoparticle therapeutic agents, thus leading to resistance to immunotherapy and gene therapy. Here we show that tumor cells were inoculated in groin lymph nodes, and the variation of IFP with time was measured by using MXH/lpr mice with human size lymph nodes. The IFP was increased in tumor bearing mouse. Corresponding changes in lymph vessels area, tumor volume, and IFP suggest that the increased pressure is caused by defective lymph drainage and solid stress generated by tumor cells growing in a low compliant environment. This study suggests a possibility for future studies of cancer metastasis.

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The EPR effect provides a great opportunity for selective targeting of solid tumors. In order to observe the EPR effect, Window chamber (WC) for chronological observation and nano particles that can extravasate from newly-formed tumoral blood vessels have been used. The solid tumor deposition method and the tumor cell injection method are both widely spread of tumor implantation methods into the WC. However, the characteristics of nano particle extravasation dependance on implantation methods have not been reported. Here we show that tumor cell injection method results in a 1.77 higher amount of extravasated particles (per surface area) than solid tumor deposition method by use of fluorescent microscope and fluorescent liposomes with an average diameter of 122 nm. We anticipate our study to help understand the EPR effect in a WC model and gain a better understanding of the EPR effect.

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This paper describes a direct drug delivery system based on a droplet with a fixed volume of water which travels down a capillary tube. In order to study flow field and chemical concentration of the moving droplet, numerical study was conducted using the Navier-Stokes equations and Fickian diffusion of chemical species with moving mesh. A commercial finite-element analysis software, COMSOL Multiphysics, was utilized to obtain numerical solutions. The relation of inlet velocity and molar concentration delivered of the droplet was investigated extensively.

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We investigated the potential of mean force (PMF) of a potassium ion across intact or pore-containing bilayers using molecular dynamics simulations with the Weighted Histogram Analysis Method (WHAM). The pore-containing bilayer was prepared by using equibiaxial stretching and constant area simulations. The umbrella samplings for various ion positions from the bilayer center to the water layer were performed with harmonic biasing potentials. In the intact bilayer, the PMF in the center of the bilayer is significantly larger than that in the water layer (-100 kJ/mol), while the difference of the PMF in the pore of the bilayer and in the water layer are small (<1 kJ/mol). This suggests that the formation of a pore in the bilayer after ultrasound irradiations may enhance the transport of potassium ions.

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This paper describes development of regenerative medical system using microcapsules including gas by shock waves. The newly proposed system has two features. One is culture mode by pressure wave , the other is rupture mode by interactions between shock waves and bubbles in microcapsules. Especially, the disintegration mechanism of polymer capsules including gas bubbles by shock wave was investigated in this paper. Deformation process of a capsule and a bubble were observed by microscopy. It was found that there are three modes such as no oscillation, oscillation, disintegration (damage) after working pressure wave (414kHz frequency) on the microcapsules. These modes show the threshold which shows the boundary of damage of a capsule, and no damage. These results serve useful data for developing of microcapsule to cultivate cells.

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This paper describes the fundamental investigations for developing new technology using pressure waves and bubbles such as drug delivery systems (DDS). The microcapsules made of lipid including gas bubble were made by controlling ultrasound and N2 gas flow rate. We examined the effect of ultrasound intensity with particle diameter and diameter ratio of gas-liquid. Also, effects of structural parameters and mechanical index on disintegration efficiency of capsule were examined. As a result, there are possibilities to disintegrate microcapsules efficiently by controlling diameter ratio of gas-liquid and rise time.

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An experiment on the interaction of a 1 MHz focused ultrasound (US) with Sonazoid microbubbles has been carried out in the presence of an agar gel. The survival number of Sonazoid microbubbles was examined by changing the exposure time Tex, the acoustic energy density E and the Sonazoid concentration Cv. High-speed photography with the maximum framing rate of 300,000 frames/s was conducted to observe the behavior of bubbles near an agar gel. It was found that bubble coalescence frequently occurred during an earlier stage after US irradiation. Subsequently a newly created bubble migrated towards the agar gel surface and away from it, behaving a kind of circulation due to an acoustic streaming. A minimum volume of a bubble was reached within a region very close to the gel surface, presumably emitting pressure waves at each rebound which could impact on the gel surface. In fact, a number of depressions in dozens nanometers were found on the agar gel surface which were detected by using an AFM.

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This paper deals numerically with the nonlinear oscillations of interacting spherical bubbles in a sound field. The thermal effects of the internal gas and liquid compressibility are taken into account in the analysis. The frequency response curves are obtained for four arrangements of bubbles with the same radii. The tempearture increase in liquid is also evaluated. It is shown that both the bubble-bubble interaction and the thermal diffusion cause the decrease of the fundamental natural frequaency of the bubble cluster leading to the shift of the frequency response curves to the lower frequency regions. When four bubbles are located at the center and three vertices of a regular triangle, the oscillation of the center bubble is enhanced by the bubble-bubble interaction, while that of the bubbles at the vertices are reduced significantly due to the difference of the phases between the center bubble and those at the vertices. The violent oscillation of the center bubble contributes to the increase of liquid temperature.

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Safety and reliability are required to control input devices in the service industry. Additionally low acoustic noise and energy saving performance are expected. In this paper, we make a prototype of link mechanism as a control input devoce using magnetic particle brakes at each joint in place of servo motors. The magnetic particle brakes are proportional torque devices. The torque is controlled by varying the excitation current. This mechanism can hold the angle of hand-operated lever and provide intelligent operational feeling passively. After the dynamics of the prototype is analized, self weight compensation and force display was realized by appropriate actuation of magnetic particle brakes to advise the reasonable operation of life supporting devices.

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We have tried to develop an Integrated Tongue Operation Assistive System; "I-to-AS". The "I-to-AS" consists of a mouthpiece type remote controller and an intraoral mini-joystick as the input devices. For the operating targets, it consists of an electric Powered Wheelchairs (PWC), and Augmentative and Alternative Communication (AAC) devices. These intraoral mini-joystick and mouthpiece type remote controller are operated by users' tongue. In this paper we improved the intraoral mini-joystick. To investigate the basic characteristic of the intraoral mini-joystick, the maneuverability was tested. The candidate of ten able-bodied male tried to operate the joystick to the correct direction that was given as random of eight directions. The duration and accuracy of the operation was estimated. The average duration was under 1[sec] and the accuracy was good enough to apply this system to the assistive tools. Five candidates tried to operate PWC on a prescribed course and the required time to goal was measured. The driving time operated by the "Intraoral Mini-Joystick" was up to 39.7% increasing as long as by the normal joystick. These suggest the possibility that this system would be effective as an assistive tool for severely disabled people.

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Omnidirectional wheelchair is easy to steer at various narrow places. But this sort of wheelchair has not become popular yet and does not have familiarity to wheelchair users. In order to get better operation, sensuous training is required for the interface of the omnidirectional wheelchair operated with only a joystick. In this paper, we developed the intuitive interface which used a touch panel and camera. In addition, by the low-cost infrared sensor arranged in the four corners of a wheelchair aimed at the prevention from a collision in the run along a narrow path or a wall. By combining these two systems, we developed a low-cost omnidiretional wheelchair which can be controlled easy and safe.

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This paper describes analysis of timbre and design of filter circuit in order to develop an assist device for tuning of shamisen. Sound of the shamisen consists of harmonic and noise components, and has a unique tone color by sawari mechanism. The shamisen has a feature that harmonics is greater than fundamental. In addition, the sound of the shamisen contains non-integer harmonics. Therefore, unrequired frequency components are filtered out used filter circuit in order to measure fundamental frequency. The filter circuit is used low pass filter of Chebychev characteristic. As a result of verification by actual equipment, it is possible to get the fundamental frequency by the filter circuit.

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For visually handicapped people, it is important to recognaize dangerous situations using white cane. However, its detection range is limited by the length of the white cane. Some previous studies try to extend this range by adding some sensors to the white cane, and such cane is called electronic white cane. In the present study, we develop small electronic white cane using smartphone, and we detect dangerous object earlier than usual white cane. In addition to smartphone, we also added an acceleration sensor and an ultrasonic sensor to get information around the cane. The data from the sensors are sent to smartphone via Bluetooth synchronously, and some data processing are performed on the smartphone. By this experiment, we could measure the distance to the wall and we could also detect on which side an obstacle exists.

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This paper describes confirmation of operation of a force display touchpad for the purpose of PC support. Recently, the elderly and/or visually impaired people who use PCs to obtain information are increasing. However, they are less than the number of other generations. It is because they have difficulty of operation of PCs. We have developed a force display touchpad for the purpose of PC support for the visually impaired and elderly. By using this device, the operator can touch the window frame in the screen of PC. In addition, the cursor will be guided to the position of the button. In this paper, we improve the software of force display touchpad, and it correspond to the windows and web browser. We confirmed the operation of these two functions in a web page.

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The warm keeping of body is very important to enhance the immune response and to maintain our health. Form the viewpoint of the concept, we have developed the Corona nano mist sauna by using the method of water fragmentation (Renard effect) and elucidated the thermal effect to human body caused by the sauna. The temperature and relative humidity of the sauna are approximately 40 ℃ and 100 %, respectively, and its atmosphere is composed of the condition which coexists with electron, oxygen molecule and H_2O cluster. On the acquisition obtained from the study, we may predict that Corona nano mist sauna makes it possible to increase the body temperature as the result of metabolism improvement and also to encourage the recovery of fatigue. This facts may suggest that O_2 (H_2O)_n as the chemical species of minus ion generated by Corona nano mist sauna plays a very important role to promote the thermal effect to human body.

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In the previous study, a belt buckle of the self-locking type belt was investigated experimentally and theoretically as well. According to the theory of belt buckle, once a belt is locked by the buckle, the belt never slips as far as belt tension is being applied. There are many people who experienced natural loosening of shoestring while walking. Using a hard locking property of belt of the buckle, we applied a small belt buckle to lash shoes. Loosening of the shoe was evaluated by measuring the contact pressure of the shoe while walking. In order to compare the lashing property of the buckle with the conventional method, magic tape and shoestring were tested. Experiments were carried out with a constant walking speed of 3.5 km/h on a treadmill. The buckle proved to be the smallest difference in pressure in walking condition among them.

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It is thought that inverse dynamics analysis is the most comprehensive method to obtain the joint reaction forces and the joint moments during gait for refining rehabilitation program of trans-femoral amputees. However, this method is highly constrained in respect to modeling of trans-femoral prosthesis and procedure of numerical computation. Alternatively, a multi-axis force/moment sensor can be used to directly measure loads applied on the middle part of trans-femoral prosthesis In this paper, loads applied on a prosthetic knee joint and lower thigh of trans-femoral prosthesis measured directly are compared with ones calculated by inverse dynamics analysis during gait. As a result of the experiments and intercomparison, comprehensive agreement between inverse dynamics analysis and direct measurement in the behaviors is obtained. Therefore, the validity of inverse dynamics analysis and the effectiveness of the developed prosthetic gait training system to consider biomechanics and comprehensive physical phenomena for trans-femoral prosthetic gait are validated.

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