In this study, we propose a material orientation optimization method for optimum design of laminated composite shell structures consisting of anisotropic materials. We aim at controlling thermal displacements to the target values without varying shape or thickness. The square displacement error norm is minimized by varying the material orientation of each layer as the design variable. The optimum design problem is formulated as a distributed-parameter optimization problem, and the sensitivity function with respect to the material orientation variation is theoretically derived based on the variational method. The optimal material orientation variations are determined by using the H¹ gradient method. The optimal design example show that the proposed optimization method can effectively obtain the optimal material orientation with the smooth curvilinear orientation distribution and tailor the thermal deformation, simultaneously.

In this paper, a non-parametric shape optimization method is proposed for designing the interface and the outer boundary shapes of a three dimensional composite structure composed of dissimilar materials in natural vibration problem. We employ a squared error norm to a target eigenvalue as the objective functional to be minimized. The shape gradient function is derived using the Lagrange multiplier method, the adjoint variable method and the material derivative method, and is applied to shape update based on the H¹ gradient method. The specified mode is traced using the MAC value. The method is applied to several design examples, and the results show that the proposed method can successfully control the vibration eigenvalue to the target, while maintaining the smoothness of the design boundaries.

In this study, we present comparison of numerical results of the magnetic field analysis between the conventional nodal-based FEM with and without the Coulomb gouge assumption and the edge element FEM. In the numerical experiments, the standard model in the Institute of Electrical Engineers of Japan was employed, and the magnetic field analysis in three dimensions was carried out. Consequently, it was found that the result by the edge element FEM is good agreement with the measurement value in comparison with the results of the conventional nodal-based FEM.

An optimization method to design micro structures of sound-absorbing poroelastic media is proposed in this study. First, Biot's parameters are identified for various microstructure of sound-absorbing material by using homogenization method and the linkage between Biot's parameters and the parameters of micro structures such as pore radius, fiber diameter and pore radius of cell membranes is derived. Then, the parameters of poroelastic materials are optimized by using transfer matrix method and genetic algorithm to maximized sound absorption coefficient at prescribed target frequency range. The optimal micro structures are verified by the homogenization method.

Thermal design in nanostructures is essential for developing miniaturized thermoelectric devices. The implementation of nanostructural designs utilizes a unique property of heat conduction, which is called as temperature jump on material interfaces. It lets us obtain novel high-performance thermoelectric materials. However, almost all reports proposed thermal-designs have been dependent on heuristic approaches and there is a large demand for constructing the optimal design methods for nanoscale thermal problems. In this paper, we propose a level set-based structural optimization method for thermoelectric materials focused on a nanoscale heat conduction problem. The level set-based method is a useful tool for a nanoscale thermal design, since the boundary effects are essential for developing novel material properties. First, we clarify a nanoscale heat conduction problem based on the Boltzmann transport equation, and define the design problem. Next, we compute a design sensitivity based on the shape sensitivity analysis. Then, we expand the level setbased structural optimization method to the nanostructural heat conduction problem. Finally, we show the validity of our proposed method via a numerical example.

This paper proposes consideration on the setting of objective functions in topology optimization for steady state incompressible viscous flow problems. The optimization problem is formulated to minimize or maximize three objective functions; difference, ratio and weghted sum of input and output energy of fluid. First one is the objective function of the conventional methods and seems to overevaluate the effect of inlet rather than outlet. Second and third one are used to assess the influence of not only inlet but also outlet properly. A curved pipe model is provided to compare each objective function and to confirm the validity of the proposed method. The optimization algorithm is developed based on these objective functions, using the level set method and the adjoint variable method for the sensitivity analysis. Design variables are updated solving a reaction diffusion equation from the concept of the topological derivative. The finite volume method is applied to solve governing, adjoint and reaction diffusion equations.

Microwave resonators are devices used for electron spin resonance spectroscopy which is expected to realize quantum computers. The performance of the microwave resonators depends on the magnetic flux density norm in the observation domain of the devices. Conventional microwave resonators have been designed to increase the magnetic flux density norm by resonance in the observation domain of the devices. However, since the structures have been made by trial and error, there would be further improvement in performance of the devices. Thus, in this research, microwave resonators are designed by level set-based topology optimization. First, the design model and the governing equations of electromagnetic wave propagation problem are explained. Second, we propose a topology optimization method for the design of microwave resonators. Third, the optimization problem is formulated so that energy concentration of magnetic field can be achieved. Finally, a numerical example is provided to confirm the usability and validity of the proposed method.

To improve walking performance in a real environment of a biped walking robot, a foot structure that flexibly follows the terrain is desired. In this research, used topology optimization method by the Finite Element Method (FEM) simulation software MSC Nastran for create foot structure. And this performed for a plurality of load patterns, a foot structure was created by combining the resulting structure patterns. And also used the Multibody Dynamics (MBD) simulation software Adams for validation of foot structure. For that reason implemented foot structure as elastic body (MNF) to whole of body model of the biped robot. As described above we tried to create a foot structure that satisfies both static and dynamic characteristics through cooperation between FEM and MBD simulation. We will report on this creation process and findings.

In multibody dynamics, the position constraint of the joint between each body is represented by a constraint equation, and the method of Lagrange multipliers is common. However, since this method is difficult to understand, it is troublesome to apply it to an actual model. As a method that does not use such an elusive analytical mechanics method, it is considered that there is hard elasticity in the joint constraining between the bodies, the reaction force and torque are calculated from the deflection between the support points, as an external force to Newton Euler's equation of motion. Both methods for simulating double rigid body pendulum: the constraint joint and the hard-elastic joint were compared. In the latter case, it was confirmed that the calculation processing time was several ten times of that of the former, but there was no problem in terms of practical accuracy.

It is important to predict the stress driven hydrogen induced cracking at the weld joint on the basis of computational mechanics from the view point of engineering problem. One of authors has been proposed α multiplication method which magnifies the hydrogen driving term in the diffusion equation to realize correctly hydrogen concentration behaviors. In this study, on the basis of proposed numerical analysis, behaviors of hydrogen diffusion and concentration during cooling process of y-grooved weld joint were analyzed and the mechanism of hydrogen induced cracking was investigated. The behaviors of hydrogen diffusion and concentration for the model of y-grooved weld joint was analyzed by combining α multiplication method with the coupled analyses of heat transfer – thermal stress – hydrogen diffusion. As a result, hydrogen was found to diffuse from weld metal to base metal through HAZ (Heat Affected Zone), and concentrate at the position of blunt angle side of weld groove bottom. It was found that hydrogen concentrates at the position of the local maximum value of hydrostatic stress gradient. This analytical result was found to well predict the actual hydrogen induced cracking of the y-grooved weld joint. Therefore, it was considered that prediction of hydrogen induced cracking becomes possible using this method of analysis.

A loading system plays a role of loading and unloading liquid hydrogen between a carrier ship and a ground storage facility in hydrogen supply chain in which hydrogen in the form of liquid phase is transported by the carrier ship from a resource-rich country to a consuming country. An emergency release system (ERS), which is one of components of the loading system, is installed in the middle of transfer pipe of the loading system, and has function of separating and plugging the pipe at an abnormality during loading so as to prevent a large amount of cryogenic fluid from scattering. We have conducted R & D study of the ERS for liquid hydrogen based on an existing one for liquid natural gas (LNG). Whole system function of the ERS including separation behavior was verified conducting a field experiment with the ERS test model and liquid hydrogen. Through several tests, the separation mechanism and behavior were verified, and also, soundness of the seal mechanism was evaluated. While, auto-ignition phenomena were observed on the separation surface of the ERS after the separation, of which causes have not been identified yet. Characteristics of dispersion behavior of hydrogen that was released at the separation could be investigated measuring distribution of temperature and hydrogen concentration around the ERS test model.

Detection of trace amounts of hydrogen in vacuum conditions is essential in reusable space transportation systems and for safety control in manned space exploration. We evaluated the H₂ detection in vacuum conditions by a novel gas sensor using sintered ceria (cerium oxide) nanoparticles. The results show that sensor resistance depended on H₂ and O₂ partial pressure ratios at any pressure from 10^-5 Pa to atmospheric pressure. We conclude that the ceria resistance does not depend on total pressure but on H₂ and O₂ adsorption. The increase in sensor resistance resulted from a decrease in oxygen vacancies dependent on the O₂ storage of ceria at a high O₂ partial pressure. On the other hand, H₂ dissociated and formed a cluster with ceria oxygen atoms when the H₂ partial pressure was higher than the O₂ partial pressure. Sensor resistance markedly decreased in these conditions because Ce³⁺ with free electrons were generated. In summary, the proposed sensor can convert gas adsorption into an electrical signal even in vacuum or anoxic conditions, and has the potential to be a highly durable device with high sensitivity.

To improve safety regulations for fuel cell vehicles and hydrogen infrastructure, experiments of cryo-compressed hydrogen leakage diffusion were conducted. The experimental apparatus can supply 90 MPa hydrogen of various temperature conditions. Measurement items were hydrogen concentration distribution, blast pressure, flame length, and radiant heat. In addition, high speed camera observation was carried out to investigate the near-field of cryogenic hydrogen jet at supercritical pressure. The experimental apparatus can supply 90 MPa hydrogen at various temperature conditions (50 K–300 K) at a maximum flow rate of 100 kg/h. The hydrogen leakage flow rate was measured using pinhole nozzles with different outlet diameters (0.2 mm, 0.4 mm, 0.7 mm, and 1 mm). It was confirmed that the hydrogen leakage flow rate increases as the supply temperature decreases. The hydrogen concentration distribution was measured by injecting high-pressure hydrogen from the 0.2-mm pinhole for 10 min under a constant pressure/temperature condition. As the hydrogen injection temperature decreased, it was found that the hydrogen concentration increased, and an empirical formula of the 1% concentration distance for the cryogenic hydrogen system was newly presented.

The purpose of study is developing modeled blood, which is able to produce thrombus formation caused by flow stagnation of blood flow, and evaluating therapeutic performance of embolic device such as intravascular treatment. This study was employed hyper-coagulable skim milk as an agglutinable modeled of blood, a uniform shear was applied by using a cone plate type viscometer. Rheological characteristics of human blood and hyper-coagulable skim milk during red thrombus / milk cot formation were measured. As a result, by changing constituents of hyper-coagulable skim milk such as concentration of skim milk, calcium chloride and rennet, it was able to model agglutination of blood caused by flow stagnation same as red thrombus formation. And the rheological specification of the modeled blood was almost same as the viscosity before agglutination and the first yield viscosity of human blood.

TAVI (Transcatheter Aortic Valve Implantation) is a minimally invasive treatment for Aortic Stenosis. Although when PVL (Paravalvular Leaks) occurred after surgery, life prognosis worsens. In this research, we made a PVL model with clearance around the orifice and compare visualization of thrombus formation on PVL flow visualized by optical system and flow field is also analyzed by CFD. Experimental result showed that PVL model thrombus formation depend on the clearance size. That is, thrombus formation in large leak model start around the leakage, whereas thrombus formation in small leak model start around the orifice. According to the CFD result, it was found that vortex and contraction existed in the flow field. It turned out that the vortex became smaller as the leakage became larger, but the contraction flow became larger as the leakage increased. Next, the difference in thrombus formation rate (Rs) near the wall compared with the clearance size. As a result, it was found that the leakage is large, the Rs increase. It was suggested that small wake by large leakage flow affected thrombus formation.

In the field of medical engineering collaboration, blood flow analysis for cardiovascular organs is a clinically significant research subject in treatment. Especially in the future, digital data such as CT / MRI can be easily prepared, and in order to realize the treatment based on numerical analysis based on individual condition of the patient by utilizing this data, it is necessary to clinical It is necessary to develop blood flow analysis. Therefore, in order to advance dissemination of blood flow analysis to the medical site, open source system which can be freely utilized freely and can be utilized as a platform for research and development is effective, and in this research, development by Stanford University and others Focusing on the analyzed blood flow analysis system SimVascular, by analyzing the function as a fluid analysis tool of this system and verifying the analysis result by the model corresponding to the actual case, it is possible to analyze the fluid analysis Consider possibility.

Some small insects can fly by using a pair of flapping wing. These flight performance is much higher than that of any existing artificial small flying objects like so-called drones which have rotary wings. Therefore, it is believed that using a pair of flapping wing following small insects makes flight performance of artificial small flying objects higher. In this report, we performed the numerical simulation of flow around flapping rectangular wing model treated as an immersed solid. We used the software “ANSYS CFX” for thermo-fluid analyses which using finite volume method. The knowledge learned from calculation results are as below. The generated forces (lift and thrust) on the wing model indicates the tendency that both positive and negative peak value increased with increasing the flapping frequency. The flapping frequency has no influence on the waveform of time variation of lift and thrust. If the wing model is down stroke, lift shows positive value and thrust shows negative value. If the wing model is up stroke, lift shows negative value and thrust shows positive value. The mounting angle of wing model has an influence on the thrust when it is less than 30°.

Since penguins prey underwater animals such as krills and small fishes, it must be important to minimize cost of swimming for the penguins. Their body surface was covered by aligned feathers of which barbs (i.e. branches of a feather) forms micro grooves similar to riblets. Here we investigate drag reduction effect of the barb structures by means of CFD (computational fluid dynamics) simulation. Firstly, we measured width and spacing of each barb for King penguin (Aptenodytes patagonicus), Humboldt penguin (Spheniscus humboldti) and Little penguin (Eudyptula minor) using museum specimens. As a result, it was found that the measured spacings were within the range of those of previouslyinvestigated riblets which reduces wall friction drag in turbulent boundary layer. Then, we created simple barb-likeriblets-models to perform static CFD simulations with RANS turbulence model using ANSYS Fluent, calculating the wall friction drag. As a result, the mimic model with spacing of 0.1 mm resulted in around 0.04% drag increase at 2 m/s flow speed, and around 0.02% drag reduction at 4 m/s flow speed in comparison with flat case. Therefore, it can be said that the barb structures in penguins are designed to prevent substantial increase in friction drag. It was also found that drag reduction effect was obtained even when incident angle of the flow increased up to 30°.

A typical example of the flow field around a moving elastic body is that around butterfly wings, which contain many veins and can undergo elastic deformation. In recent years, quantitative flow visualization techniques, such as Particle Image Velocimetry (PIV) measurement, have advanced rapidly, and the flow fields around insect wings have been actively investigated using such techniques. The characteristics of the dynamic forces generated by the flapping insect wing have attracted a great deal of attention. However, the characteristics of dynamic forces generated by the flapping insect wing are not yet sufficiently understood. The purpose of the present study is to investigate the characteristics of dynamic lift generated by the flapping butterfly wing. We measured the dynamic lift produced by a flapping butterfly, using a six-axes sensor. The sixaxes sensor was synchronized with a high speed camera to capture the flapping motion of the wing, and the dynamic lift was related to the flapping motion of the butterfly wing.

Many bacteria are changed the frequency of tumbles depending on the environment, and it indicate overall movements towards attractants (chemotaxis). In this study, we aim to clarify the relationship between the runs-and-tumbles motion and the chemical environment. Microinjection was employed to observe a single cell of Salmonella typhimurium SJW 1103 swimming around a capillary which contains chemo-attractant, L-serine.

Each cell clearly showed chemotactic behavior: motion of each cell is limited within the range of about 100 micrometers from the tip of the capillary, and mean square displacement of the cell converges to a corresponding value. We have been looking for the reason why the motion is confined. No difference in run duration, the period between two consecutive tumbles, was observed between the motions approaching and leaving the attractant source. This implies that other factors in runs-and-tumbles motion determine the characteristics of the chemotactic behavior.

In this report, I describe the relationship between CPAP pressure and Sub pressure and ventilation flow rate when changing tidal volume (2ml～8ml) of spontaneous breathing simulator(PT-2) while keeping MAP constant .As a result of the experiment, the following was found. ①As the amount of tidal volume increase, the minimum pressure value during inspiration has dropped from -20Pa to -150Pa above the set MAP. ②Based on the Sub pressure (-55Pa) in the stopped state of the diaphragm, the Sub pressure increases just before atmospheric pressure at the time of inspiration, and the ventilation flow rate pushes up the potential core at the time of exhalation, a part thereof flows out to the bypath flow path, and the Sub pressure decompresses to -200Pa during expiration.③The CPAP pressure is decompressed lower than the setting MAP by a completely different mechanism at the time inspiration and expiration.④From the above results, this device shall be a respiratory response type Nasal CPAP device. Since it was possible to observe respiratory state with small ventilation as change of CPAP pressure and Sub pressure, the possibility of this device as an interface applicable to super birth weight infants was shown.

Coronary artery aneurysm (CAA) is an unusual disease whose incidence was reported as 0.14-4.9%. Currently, CAA usually is treated with coronary artery bypass grafting (CABG) surgery. However, there is limited evidence to prove which operation procedure, including bypass by saphenous vein graft (SVG) or left internal mammary artery (LIMA) with or without ligation of CAA, is better to treat this disease. At present, studies have shown that hemodynamic parameters are an important basis which can supply evidence to make the evaluation for different surgery. Therefore, we study the feasibility of different operating procedures from a hemodynamic point of view. Here we present four 3D models with coronary arteries and aortic arch named Model 1-4 (SVG/LIMA with CAA, SVG/LIMA without CAA, respectively). In order to reduce the computational requirements and obtain good boundary conditions, lumped parameter model (LPM, 0D model) coupled with 3D models. The mass-flow of SVG and LIMA, wall shear stress (WSS) and oscillatory shear index (OSI) were evaluated. Normal WSS and low OSI in grafting region appeared in Model 1, 3, and 4. Inverse flow, normal WSS, and high OSI put in an appearance on the LIMA in Model 2. Based on previous work, inverse graft flow and high OSI can make bypass graft invalid. Therefore, from a hemodynamic point of view, SVG and LIMA both can be used as the bypass graft to treat the CAA. However, CAA should be ligated when LIMA is used.

Cerebral aneurysm rupture is a fatal disease. While clipping has been widely recognized as a standard method, flow-diverting stent treatment is becoming common in US and EU. However, some clinical studies indicate that the stent placement works negatively, particularly in large aneurysm cases. In this study, therefore, we perform direct numerical simulations for spherical aneurysm models to investigate the flow characteristics in several types of aneurysm. The diameters of the aneurysm models are set to D=8mm and D=12mm. A flow diverter stent based on the pipeline stent is installed to cover the neck of the aneurysm. The results show that the flow pattern drastically changes by the stent installation. In the case of D=8mm, the flow direction in the aneurysm changes from counter-clockwise to clockwise. On the other hand, in the case of D=12mm, while the pattern changes as in the case of 8mm aneurysm at the beat peak, it becomes clockwise in the diastole phase. The peak pressure is slightly decreased by the stent placement in the case of D=8mm whereas it is increased in the case of D=12mm.

Cells exert a mechanical force on the environment and also perceive the mechanical force from their environment. The hardness of the substrate, the shape of the cells, contact with other cells, etc. affect the cells as the environmental forces from the environment. It has been suggested that environmental forces can influence cell differentiation. However, conventional on-gel cultivation is generally performed by applying a gel-like substance such as a hydrogel on a dish or filling it in a device, and It is impossible to accurately control the shape and thickness of the gel. Therefore, in view of industrialization of regenerative medicine, a question remains about its stability. In addition, since cells change their intracellular structure and protein localization depending on their shapes, it is difficult to realize a stable culture and quantitatively evaluates with conventional on-gel cultivation. In this study, we have developed a cell culture gel which can not be accurately controlled in shape by combining fine processing technology and inkjet technology and enables patterning of cells capable of stable cell culture A gel substrate for culture was prepared. We used reactive ion etching (RIE) to fabricate a number of cell chambers on a cover glass. Silicone was accurately filled in each chamber using inkjet technology. A thin oxide layer on a silicone elastomer was formed in a reproducible and spatially uniform manner using oxygen plasma instead of the gas burner flame. This gel substrate can also be applied to evaluation techniques that can evaluate the cell contraction force applying gel culture on research currently under development. Using this substrate that enables us to simultaneously perform cell patterning and cellular traction force visualization, we attempt to develop a cell-based assay for drug evaluation.

This paper describes a fabrication method of a multi-layer heterogeneous polymer gel tube device. The device can be easily fabricated by the repetition of a simple molding process, and the device works as an in vitro 3D engineered scaffold by encapsulating multiple types of cells during fabrication process. Thicknesses and the numbers of the layers can be flexibly designed by changing the mold size, and the perfusion culture can be easily performed by just connecting external pump system to silicone tubes of the device. We fabricated several different size and material types of devices, and succeeded in controlling coefficients of variation of the size to be lower than 5%. We succeeded in cultivating several types of cells in and on the collagen tubes. We believe that this method could help the easy reproduction of various complicated in vivo tissues, and contribute to the development of regenerative medicine and pharmacokinetic testing.

Three-dimensionally printed objects with photo-curable resin generally have high toxicity to cells, making it difficult to apply them to living systems. This paper reports a technique to construct a three-dimensional object in a glass chamber by aggregating microgels, which are polymers of N-isopropylacrylamide (NiPAm) and glycidyl methacrylate (GMA). We aggregated the microgels whose have a higher biocompatibility than the photo-curable resin by relatively diamagnetic assembly. Microgels were positively or negatively charged by modifying GMA with 2-aminoethanethiol (AET) or sodium 3-mercapto-1-propanesulfonate (MPSA). Two kinds of microgels having positive and negative charges were mixed and then their aggregate was formed at one place by a magnetic field. It was confirmed that the aggregate shrinks and expands at a shrinkage rate of about 10% by heating to 40°C and cooling to 25°C. The results show that the modeling method by aggregating electrically charged microgels based on relative diamagnetism is one of the most promising approaches for biocompatible three-dimensional printing and the formed objects could be further applied for a thermoresponsive actuator.

For the purpose of application to biosensors, we newly characterized the electrical properties of the λDNA molecules. After the λDNA molecules were introduced using a microchannel measuring 50 μm in depth and 500 μm in width, they were electrostatically stretched and immobilized between two triangular-shaped aluminum electrodes with a gap of 14 μm by applying an AC voltage of 1 MHz and 20 V_p-p. In order to reveal the detailed electrical properties such as parasitic resistance, and parasitic capacitance which are attributed to the conductivity of λDNA molecules, we evaluated the impedance frequency characteristics of the λDNA molecules using EIS (Electrochemical impedance spectroscopy) measurements. From the complex impedance of the λDNA molecules, an equivalent circuit was obtained as a series connection of two parallel circuits consisting of two resistances and two parasitic capacitances. The DNA molecules which were immobilized and evaluated in this study can be applied to electrical detection of deoxyribonuclease (DNase), enzyme for nonspecific DNA cleavage, which is a candidate biomarker for acute myocardial infarction.

Dental ceramics are affected by milling process of CAM machine, and these surfaces are caused micro-cracks. This problem leads to cause severe fracture and reduce the fatigue life. The aim of this study is to eliminate the micro-crack of dental ceramics surface by using micro slurry-jet (MSJ) process. MSJ is a blasting technique that uses fine particles as the abrasive media, along with compressed air and pure water. In this study, CERASMART 270 that is composite resin ceramics was used as a specimen. The surface of specimens was adjusted MSJ process after polishing with #1500 sandpaper and dental abrasive. The MSJ processed and polished surfaces were observed using a laser microscopy to examined residual defects and micro-cracks. As a result, it was found that residual defects and micro-cracks on the surface after polishing could be able to expose and eliminate. This study showed that MSJ process is an effective technique for eliminating residual defects and micro-cracks on the surface of dental ceramics.

We investigated the method for measuring extracellular electric potential stably by using electronic sheet. Electronic sheet is composed of parylene film and electrode. The thickness of electronic sheet we fabricated in this study is only 500 nm. Therefore, it is really flexible. So, it can follow the movement of cardiomyocyte and measure extracellular electric potential. We are thinking of applying it for drug evaluation system. To achieve this, high stability electrode is needed. Therefore. we focused on the configuration of electrode on electronic sheet. It is well known that chromium layer enhances the adhesion force between gold electrode and substrate. In this paper, we report the difference of stability from presence or absence of chromium layer. It is suggested that chromium layer increase the stability of electronic sheet.

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 a microfluidic probe (MFP) channel which has a pair of the injection and aspiration channels installed on the ceiling of the cell culture chamber. A local stimulation area within the cell chamber can be controlled by the flow ratio of injection/aspiration channels. Also, it is possible to culture cells under perfusion by aspirating the culture medium from the reservoir using a syringe pump. To achieve precise fluid handling, the device was installed into the jig as an interface to syringe pumps. The device has been evaluated by fluidic simulation using Finite Element Method (FEM), a flow control experiment and chemical stimulation experiment on cells. The result showed that control of chemical stimulation from several cells to cell population scale in the chamber can be possible by regulating the flow ratio. The local chemical stimulation area enables grasped by fluidic simulation because the result of the experiment and simulation are approximate in case of flow control experiment and cell staining experiment. In addition, Ca²⁺ propagation in response to chemical factors was observed using the device. We conclude that the device can be powerful tool for biological applications such as the differentiation control of pluripotent stem cells and other cells signaling studies.

This paper presents the influence of surface condition of titanium on cell adhesion, cell activity and cell differentiation. It is well known that photofunctionalization on titanium surfaces promotes the osteogenesis. It is common knowledge that cells strongly adhere to UV irradiated titanium substrate because UV surface modification improves affinity of titanium surface and cells. However, there are not many studies investigating the influence on cell dynamics and cellular activity changes by VUV irradiation time. In this study, a titanium substrate treated with various VUV irradiation times was used. First, colorimetric analysis using methylene blue was carried out in order to investigate the properties of ultraviolet irradiation surface. Further osteoblasts were used. Cell morphology was evaluated by fluorescence microscopy. Cell activity and cell differentiation were evaluated using absorbance measurements. As a result of the experiment, Cell adhesion was improved by VUV irradiation. On the other hand, cell activity and ALP production amount changed depending on the irradiation time.

This paper describes a DNA aptamer linked structural color hydrogel sensor that can optically detect silver ions by naked eyes and camera-based smart devices. Structural color is expressed by Bragg's diffraction of colloid crystal. DNA aptamer is single-stranded DNA that binds to a specific target molecule and changes its secondary structure. The hydrogel integrating colloid crystal and DNA aptamer can convert the target concentration to visible color change, which can be detected by human naked eyes. As a preparation for fabricating the gel sensor, we fabricated a silica colloid crystal solution and controlled the color by arranging its particle concentration. In addition, we confirmed the response of DNA aptamer linked gel to silver acetate solution. This sensor could be applied to various areas such as point of care testing, food and water safety, and so on. We believe that our approach could be effective to construct aptamer-based optical biosensors.

In this paper, we succeeded in releasing 20 nm fluorescent silica particles, which is approximately the same size as Adeno-Associated Virus (AAV), by a composite structure of calcium alginate and collagen. Alginate microparticles encapsulating fluorescent silica were prepared using a centrifuge based microfluidic device, which was mixed with collagen and solidified to produce a composite hydrogel structure. Alginate lyase was applied to the complete hydrogel to dissolve only alginate microparticles, resulting in release of, fluorescent silica nanoparticles by permeating collagen. We also confirmed the effect on cells in this release system by performing live/dead assay. Almost all cells continued to live for 3 days after the releasing nanoparticles, meaning that there was no cytotoxicity to cells. In the future, we will encapsulate AAV in alginate microparticles to apply our method to a practical DDS system for gene therapy.

From a biological point of view, wrinkles due to photo-aging are caused by active oxygen and wrinkles due to drying are caused by inflammatory cytokines. However, it is not clear how the mechanism that determines the shape and the size of wrinkles works. Therefore, for the purpose of investigating the mechanism of wrinkle formation, three-layer structure consisting of stratum corneum, epidermis, dermis was modeled with finite element. We assumed an isotropic and homogeneous linear elastic body for each layer of the skin. The buckling analysis was performed under several conditions in which the elastic modulus of each layer of the skin was changed. As a result, wrinkles about 0.1 mm in size were formed in young age and wrinkles about 0.3-0.5 mm in size were formed in old age.