著者

Michihiko FUKUNAGA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.18, no.3, pp.23-00103, 2023 (Released:2023-07-25)

参考文献数

9

---

Tremolo is a technique to produce the same note continuously in short spans, and is an important technique for musical performance on a mandolin. However, it is not easy for beginners to master this technique, nor is it easy for even expert players to perform a wide range of expressions. There is no unified view on the proper behavior of tremolo playing, and there are no examples of measured tremolo behavior. In this study, we measured the hand movements during tremolo playing on a mandolin. One test subject was included in this study. An inertial sensor was attached to the back of the hand, and the movement was evaluated by the angles which were the time integrated angular velocity on each axis. Tremolo playing is a combination of elbow and wrist motion. We examined how those motions were used for playing strong/weak tones or fast/slow tremolos. The results showed that there was a clear difference in motion between tremolo using the wrist and tremolo using the elbow. The results also suggested that the combination of each joint motion was changed when adjusting the volume and tremolo speed. It indicated that the measurement of hand movements by inertial sensors could be used to evaluate tremolo playing. Our future plan includes a more detailed analysis of the relationship between musical expression and tremolo movement, and an examination of how movement changes with practice.

著者

Michio MURAKOSHI Hiroshi WADA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.16, no.3, pp.21-00125, 2021 (Released:2021-09-15)

参考文献数

38

---

The high sensitivity of mammalian hearing is achieved by cochlear amplification. The basis of this amplification is the motility of outer hair cells (OHCs), which are sensory cells in the inner ear. This motility may be due to voltage-dependent conformational changes of the motor protein prestin, which is densely embedded in the lateral membrane of OHCs. However, the membrane structure of prestin has not yet been elucidated. Therefore, the membrane structure of prestin was herein investigated by force spectroscopy using an atomic force microscope (AFM). The gene of prestin fused with an Avi-tag at its C terminus was transfected into Chinese hamster ovary (CHO) cells and the inside-out plasma membrane was isolated. The Avi-tag was enzymatically biotinylated and attached to a streptavidin-coated AFM cantilever via biotin-streptavidin binding. Prestin was then pulled out from the plasma membrane and the relationship between the force applied to the protein and the extension distance, i.e., the force-extension (FE) curve, was assessed. The curves obtained showed saw-toothed patterns. An attempt was then made to analyze these curves using the worm-like chain model. The force caused by stretching of the intracellular C terminus and that due to the extraction of one or several transmembrane domains were identified. The present results imply that the C terminus and the subsequent transmembrane domains of prestin correspond to those of the previously reported model with 12 transmembrane domains.

著者

Yoshinobu INADA Naoki TAMIYA Maako MIYAKE Tadamichi MORISAKA Mai SAKAI Ikuo WAKABAYASHI Masahiko KASAMATSU Yasuhiro UEKUSA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.12, no.3, pp.16-00700, 2017 (Released:2017-07-21)

参考文献数

13

被引用文献数

1

---

The finless porpoise has characteristic tubercles on its dorsal ridge. These tubercles are supposed to have biological and mechanical functions. In the former, specific nerve endings and fibers exist in the tubercles indicating its function as a sensory organ. In the latter, tubercles provide fluid dynamic functions such as underwater drag reduction or inhibition of wave or spray drag while breathing at the sea surface. This research focuses on the latter function aiming at the application to the drag reduction in moving vehicles. Small projection models, or tubercle models were fabricated with resin and tested in the wind tunnel to investigate the effect on the lift and the drag characteristics of an airplane model with the tubercle models attached on the wing-fuselage connection. In consequence, it was shown that the tubercles effectively delayed the wing stall at high angles of attack without largely degrading the wing performance. The oil flow experiments also clarified that this delay of wing stall was caused by the inhibition of flow separation on the wing surface. The tubercles then had a positive influence on the flow around the wing or fuselage effectively inhibiting the flow separation and thus may be a useful device to reduce drag, noise, or vibration of moving vehicles.

著者

Jeonghyun KIM Hiroyuki KIGAMI Taiji ADACHI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.15, no.3, pp.20-00227, 2020 (Released:2020-07-24)

参考文献数

21

被引用文献数

6

---

Osteocyte plays a central role as a commander in the bone to modulate bone remodeling processes. While the osteocyte is known to be differentiated from osteoblasts, understanding in mechanism of the osteocyte differentiation remained still poor. The aim of this study is to elucidate the osteocyte differentiation capability using three-dimensional (3D) cell culture technique. We first fabricated a self-organized spheroid reconstructed by mouse osteoblast-like cells by adjusting the number of subcultured cells in the round-bottom well. Compared to a conventional two-dimensional (2D) monolayer model, the 3D spheroid exerted greater osteocyte gene expressions in vitro within 2 days. As a result of the size-dependent experiment, there might be an appropriate cell-cell and cell-ECM interaction for osteoblast-like cells to induce the osteocytogenesis in the form of 3D spheroid culture. Moreover, the present model showed that the spheroid further exerted the prolonged osteocyte differentiation capability after a long period of incubation, 7 days. In conclusion, we characterized the self-organized osteocytic spheroids reconstructed by osteoblast-like cells and further suggested the potential application of the spheroid as a new in vitro tissue-engineered osteocytic model.

著者

Shoko OIKAWA Yasuhiro MATSUI Asato WAKABAYASHI Sayaka GOMEI Hiromichi NAKADATE Shigeru AOMURA

出版者

一般社団法人 日本機械学会

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.15-00613, (Released:2016-04-06)

参考文献数

12

被引用文献数

7

---

For cyclist fatalities in 2014 in Japan, the head was the most frequently injured body region. In the present study, the authors analyzed the features of cyclist head injuries in real-world traffic accidents using the data of patients who were taken to the emergency room in Dokkyo Medical University Koshigaya Hospital in Japan, from 2011 to 2013. The results indicated that the percentage of skull fractures was the highest among cyclist head injuries. Assuming that a helmet can prevent head injuries sustained by cyclists in traffic accidents, the effect of wearing a helmet was investigated in impact tests against a vehicle and road pavement. In the tests, the severity of potential head injuries was determined from the Head Injury Criterion (HIC) obtained in an adult pedestrian head-form impactor with and without a helmet. The impact location selected for a vehicle was the A-pillar because the pillar had much higher stiffness than the vehicle bonnet or windshield. It was found that the HIC values for the head-form impactor wearing a helmet were much lower than the HIC values for the head-form impactor not wearing a helmet in both the head-versus-A-pillar impacts and head-versus-pavement impacts. The results suggest that wearing a helmet could reduce the possibility of skull fracture in cyclists.

著者

Yoshitaka NAKANISHI Shou HOSOKAWA Yuta NAKASHIMA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.20-00531, (Released:2021-07-30)

参考文献数

30

---

Various effects have been observed when a slimy fluid is held in palmar skin. The observed effects include friction control of the skin and cleansing and moisturizing of the skin. However, few reports exist regarding the changes in the emotional state of persons when a slimy fluid is held in their palmar skin, even though the viscosity properties of the fluid affect emotional changes. Thus, this study investigates the emotional changes due to holding slimy fluid in the palmar skin by evaluating heart rate variability (HRV) and sensibility. Newtonian and non-Newtonian fluids, with viscosities ranging from 0.01 to 100 Pa·s, were prepared. Eight male subjects in their 20s soaked their palms in the slimy fluid without seeing it. At the room temperature of 25 °C, the subjects moved their palms freely for 1 min. They were allowed to rub their palms together. During the experiments, the HRV was recorded. A frequency analysis was performed for estimating autonomic nerve activity. After holding the fluid, the subjects were asked to provide feedback through the semantic differential method. Significant changes in autonomic nerve activations were observed when the subjects soaked their palms in the slimy fluid. The high viscosity Newtonian fluid reduced the parasympathetic nervous system activity. These changes in the psychophysiological indexes influenced the feelings of the subjects ascertained according to the semantic differential method. A relationship between the characteristic of the slimy fluid and a psychophysiological index can improve the efficiency when developing products exposed to human skin.

著者

Tatsushi TOKUYASU Shimpei MATSUMOTO

出版者

一般社団法人 日本機械学会

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.8, no.1, pp.94-103, 2013 (Released:2013-06-06)

参考文献数

9

被引用文献数

1 3

---

The saddle height of a cycle road racer influences the competitive performance of the cyclist. Cyclists can adjust the saddle height carefully according to their kinesthetic sense while riding a bicycle. The saddle height control system we have developed consists of a saddle height control device and a measurement instrument for a surface electromyogram (SEMG). The evaluation criteria for the saddle height based on SEMG signals, which are measured from the leg muscles during pedaling exercise, are established. Our experiments indicate that the saddle height was controlled at a relatively low level regardless of the cycling level of the subjects. The effects of muscle fatigue due to pedaling exercise are suspected to affect these experimental results.

著者

Shoko OIKAWA Hiromichi NAKADATE Yuelin ZHANG Takahiro UENO Shigeru AOMURA Yasuhiro MATSUI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.12, no.4, pp.17-00175, 2017 (Released:2017-09-15)

参考文献数

49

被引用文献数

1

---

Severe head injuries can occur in cyclists involved in traffic accidents. In Japan, head injuries accounted for 62% of cyclist fatalities in 2015 (ITARDA, 2016). The purpose of this study is to estimate head injuries for cyclists and quantify the effectiveness of a bicycle helmet by performing finite element (FE) simulations of head impacts against roads. Impacts with and without a helmet over a range of relative head velocities and head impact angles were simulated. A number of possible head injuries were assessed; skull fracture by skull strain, traumatic intracerebral hematoma (ICH) by brain pressure, brain contusion by brain negative-pressure and von Mises stress, and moderate and severe diffuse axonal injuries (DAIs) by von Mises stress. Results showed that without a helmet, the peak values of all metrics exceeded the 50% probability point for head injury in all impacts. The 50% probability points of moderate and severe DAIs were exceeded under impacts of 8.22 m/s at 26.5 degrees and 10.33 m/s at 15.0 degrees for moderate DAI, and 10.33 m/s at 15.0 degrees for severe DAI, without a helmet. All the peak values were reduced when a bicycle helmet was worn, and the largest reduction was found in the skull strain. These results predict that the risks of head injuries due to road impacts may be considerably decreased by helmet use.

著者

Motomu NAKASHIMA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.4, no.1, pp.94-104, 2009 (Released:2009-01-30)

参考文献数

8

被引用文献数

40 42

---

The objectives of this study were to investigate the effect of trunk undulation on the swimming performance in underwater dolphin kick, and to clarify the ideal trunk undulation form. The reference swimming motion of an elite swimmer was firstly acquired from the video analysis, and input into the swimming human simulation model SWUM, which had been developed by the authors. The trunk motion was next optimized by the simulation for three objective functions: maximizing swimming speed, maximizing propulsive efficiency, and minimizing fluid force acting on hands. The following findings were obtained: In the case of maximizing swimming speed, the whole body forms a ‘C’ shape due to the in-phase trunk undulation. The swimming motion of maximizing propulsive efficiency and the reference swimming are considerably similar to each other. In both cases, the trunk moves as a seesaw with a node; whereas, the lower limbs form a traveling wave in the absolute space. The values of propulsive efficiency are around 0.2 in the cases of maximizing propulsive efficiency, minimizing fluid force on hands, and the reference swimming. The swimming motion in the case of minimizing fluid force on hands is almost the same as that of maximizing propulsive efficiency. The trunk undulation with the appropriate amplitudes and phases, especially bending at the chest, is important in realizing the swimming motion which maximizes propulsive efficiency.

著者

Saran KEERATIHATTAYAKORN Satoshi YAMADA Shigeru TADANO

出版者

一般社団法人 日本機械学会

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.15-00423, (Released:2015-09-07)

参考文献数

27

被引用文献数

1 1

---

The authors proposed an electromyography computed tomography (EMG-CT) method to measure the distribution of muscle activity in the forearm using surface EMG signals from multiple surface electrodes. The present study is to develop a method to estimate muscle stress, i.e., force generated during contraction per unit area in the whole cross-section of the forearm based on EMG-CT. While three subjects performed hand gripping trials using three hand grip devices, EMG signals around the forearm were measured using EMG-CT. An EMG conduction model of the forearm was constructed using an outline geometry of the subjects' forearm which was measured with a handy 3D scanner. The stress of muscle was calculated from the relationship between gripping force and total muscle activity. As a result, the distribution of muscle stress in the forearm during hand gripping was visualized in a tomographic image. It was clear that the stress was concentrated in the flexor digitorum superficialis, flexor digitorum profundus, flexor carpi radialis, and extensor digitorum communis region. The maximum stress in the forearm muscles increased from 0.08 ± 0.01 to 0.18 ± 0.02 MPa when gripping force increased from 77 to 242 N. This study provides a novel method of measuring muscle stress in forearm.

著者

Yo KOBAYASHI Takahiro SATO Takeharu HOSHI Masakatsu G. FUJIE

出版者

一般社団法人 日本機械学会

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.7, no.3, pp.305-317, 2012 (Released:2012-06-15)

参考文献数

23

---

Needle insertion treatments require accurate placement of a needle tip into the target cancer. However, it is difficult to insert the needle into a lesion because of tumor displacement during organ deformation. Therefore, path planning using a needle insertion simulation to analyze deformation of an organ is important for accurate needle insertion. A frictional model for needle insertion simulation is presented in this report. In particular, we focus on a model of frictional force based on the relative velocity between a needle and liver tissue ranging from hyper to slow velocity. In vitro experiments using porcine liver were performed at several relative velocities to measure the velocity dependence of the frictional force. Sixty trials of frictional force data were used to obtain average data at each relative velocity. The model of frictional force was then developed using the averages of the experimental results. This model was defined according to relative velocity, including hyper-slow velocity. Our modeling and experimental results show that the frictional force between the tissue and the needle increased during low relative velocity (under 1.5mm/s) and became constant (over 1.5mm/s).

著者

Akisue KURAMOTO Motomu NAKASHIMA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.22-00469, (Released:2023-09-01)

参考文献数

18

---

This study aims to confirm the effects of a neck pillow on the postural stability of the head and neck and the variance of center of mass in a sitting position. Experiments were conducted on keeping a sitting posture at rest with and without the use of two types of neck pillows; the neck wrap pillow and the front neck pillow. During experiments, whole body posture was recorded by a motion capture system. Differences in head-and-neck postural stability and center of mass variance in the resting sitting position were statistically compared among the neck pillow conditions. As a result, it was confirmed that the front neck pillow increases the postural stability of the head and neck in a resting sitting position and reduces the variation of the center of mass.

著者

Yuta MURAYAMA Toshiyuki NAKATA Hao LIU

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.18, no.1, pp.22-00340, 2023 (Released:2023-01-16)

参考文献数

31

被引用文献数

2

---

Flying animals such as insects, bats, and birds have acquired the ability to achieve diverse and robust flight patterns in various natural environments. Their sophisticated morphologies, kinematics, and dynamics have motivated engineers to develop bioinspired flying robots. Particularly, the capabilities of morphing wing and tail controls in birds have received significant attention. Such controls are expected to introduce novel mechanisms to achieve flight stabilization while maintaining high maneuverability with a low energy cost. While the control of tail posture and motion is considered to exhibit a significant influence on flight performance, there have been few studies focusing on control with multiple degrees of freedom in small flying robots. In this study, we developed a bird-inspired morphing tail mechanism; a model was fabricated and investigated its aerodynamic performance through wind tunnel experiments. The results indicate that the tail attitude can be controlled effectively to enable the enhancement of aerodynamic performance in terms of mechanical efficiency and controllability. We also verified that controlling the tail attitude is redundant in the control of aerodynamic force and moment production, implying the potential capability to achieve stable flight control strategies in response to various disturbances. Therefore, our results indicate that tail-attitude-based aerodynamic control may be able to cope with the conflicting requirements of improving stability and maneuverability of flyers.

著者

Sakito KOIZUMI Toshiyuki NAKATA Hao LIU

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.18, no.1, pp.22-00347, 2023 (Released:2023-01-16)

参考文献数

38

被引用文献数

2

---

Flying insects are capable of hovering and rapid maneuver under unpredictable environments. The principal wing-beat is generated by transmitting the rhythmical contractions of power muscles to the exoskeleton and wing-base articulation. Fine-tuning of the flapping wing kinematics is achieved by deforming the articulation with tiny steering muscles. This flapping mechanism of insect flight is distinct from that of conventional man-made aerial vehicles, enabling superior flight. In this study, we propose an insect-inspired flapping mechanism, which is comprised of two different types of actuators and a flexible wing-base structure. The flapping mechanism is driven by electric motors, which modulate wing kinematics by adjusting the flexible wing-base structure using electromagnetic actuators (EMAs). First, the EMA design was optimized based on analysis of the dynamic forces and displacements to enable deformations of the wing-base structure. A prototype flapping mechanism was then constructed, and its performance was evaluated experimentally by adjusting the actuation phase of the EMAs being synchronized with flapping motions of the wing. The results indicate that the wingbeat kinematics and aerodynamic performance are noticeably sensitive to the actuation timing of EMAs and can thus be controlled by tuning the EMA actuating timing and direction. The flapping mechanism can potentially be applied as a novel means for controlling body posture of flapping-wing micro air vehicles to achieve insect-inspired stable flights in natural environments.

著者

Yu MORIWAKI Nobuo SAKAI Yoshinori SAWAE Teruo MURAKAMI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.4, no.1, pp.153-164, 2009 (Released:2009-05-12)

参考文献数

10

---

The human forearm with elbow joint has two degrees of freedom of motion. Especially it is noticed that the wide range for the rotation of the forearm (pronation-supination) is attained according to the sophisticated complexity of the human forearm with elbow joint. The elucidation of its movement mechanism is useful for the functional evaluation for the medical treatment and application to the welfare devices for the upper limb. The purpose of this study is to develop the arm model that functionally mimics the musculoskeletal system of the human forearm with elbow joint. In this paper, we made a physical model and the computational models, which replicate the bionic function of the forearm with elbow joint. By estimating the moment arms in a physical model, the mobility of the simplified physical model was evaluated. In the three-dimensional computational forearm bone models different in the geometry, the beneficial property of the centroidal lines of the bones was confirmed to extend the range of motion for the pronation-supination.

著者

Motomu NAKASHIMA Shun MAEDA Takahiro MIWA Hiroshi ICHIKAWA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.7, no.2, pp.102-117, 2012 (Released:2012-03-13)

参考文献数

32

被引用文献数

26 25

---

In this study, the optimal arm strokes in crawl swimming which maximize the swimming speed and propulsive efficiency were solved computationally. For this objective, an optimizing method which consisted of the random search and the PSO (Particle Swarm Optimization) algorithm was constructed. In order to consider the muscle strength characteristics of the swimmer as the constraint condition of the optimization, an experiment to measure the maximum joint torques was carried out for various joint angles and angular speeds. Using the measured experimental data as the reference values, a musculoskeletal simulation model was constructed. By the constructed musculoskeletal model, muscle strength characteristics in various conditions were investigated and used to create a database. Using this database, the optimizing calculation was finally conducted and the following results were obtained: In the optimization maximizing the swimming speed, the swimming speed became maximum when the stroke cycle was 0.9 s. A relatively I-shaped stroke was obtained in this case. In the optimization maximizing the propulsive efficiency, the propulsive efficiency became maximum when the stroke cycle was 1.3 s. A relatively S-shaped stroke was obtained in this case. Two strokes which respectively maximized the swimming speed and propulsive efficiency were very similar to each other when the stroke cycles were the same. The swimming speeds and stroke cycles obtained in the optimizing calculation were within reasonable ranges compared to the actual races.

著者

Shin'ichiro KANOH Ko-ichiro MIYAMOTO Tatsuo YOSHINOBU

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.5, no.1, pp.32-40, 2010 (Released:2010-01-29)

参考文献数

8

被引用文献数

9 14

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An auditory brain-computer interface (BCI) which detects event-related potentials (ERPs) elicited by selective attention to one of the tone streams was proposed. Two frequency oddball tone sequences with different tone frequency ranges were alternately presented to subjects, and were perceived by subjects as two kinds of segregated streams. Event-related potentials elicited by two kinds of deviant tones were classified by linear discriminant analysis (LDA) to find the stream subjects paid selective attention to. Experiments with six subjects have shown that this system could realize binary selection from two tone streams.

著者

Masateru MAEDA Hao LIU

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

vol.8, no.4, pp.344-355, 2013 (Released:2013-12-24)

参考文献数

15

被引用文献数

10 22

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In very few studies it is shown that an increase in vertical force can be achieved when a flapping-wing hovers in ground effect (IGE). The body, however, has usually been neglected and its influence on three-dimensional vortex structures and consequent aerodynamic forces is still unclear. In this study we carried out a computational fluid dynamic study of a fruit fly (Drosophila melanogaster) hovering for two cases: “in ground effect” and “out of ground effect” (OGE), where the heights from the ground are less than one and more than five times the wing length, respectively. The wings in the IGE computation generated merely 0.7% larger wingbeat cycle-averaged vertical force than in the OGE condition. The body, in contrast, exhibited a significant increase in the vertical force: when out of ground effect, the average vertical force of the body was almost zero (-0.0025 μN); whereas in ground effect, the force increased to 0.78 μN, which is the major contributor to the 8.5% increase in the total vertical force (from 9.9 μN at OGE to 10.8 μN at IGE). Meanwhile, the aerodynamic power of the wings decreased by 1.6%, resulting in a 10% improvement in the overall vertical force-to-aerodynamic power ratio. The flow-field visualization revealed that the downwashes generated by the wings create a high pressure “air cushion” underneath the body, which should be responsible for the enhancement of the body vertical force production. Our results point to the importance of the presence of body in predicting the vertical forces in flapping flights in ground effect.

著者

Toru HAMASAKI Takahiro YAMAGUCHI Masami IWAMOTO

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.17-00575, (Released:2018-01-18)

参考文献数

30

被引用文献数

15

---

It is difficult to experimentally observe the influence of differences in individual skin properties of human fingers on tactile perceptions. During subjective experiments, many parameters, such as skin properties, the transmittance of nerve signals, and individual feelings are intricately mixed; therefore, it is difficult to identify which elements are affected and to what extent. It has not been determined how age-related changes in the stiffness of skin influence tactile perceptions. We developed a two-dimensional cross-section human fingertip finite element model based on previous studies. Then, we estimated the influence of age-related changes in skin stiffness on Merkel cells and tactile perceptions by using finite element analysis. Age-related changes in skin stiffness were described by changing skin material properties in the model. Simulations using a model involving the fingertip being contacted with a rigid flat plate or a 2-point indenter were performed. Using a rigid flat plate and standard skin material properties, the contact width between the finger pad and the object was 5 mm. Meanwhile, the width changed from 5 mm to 4 mm when using a model of age-related changes of skin. Using a rigid 2-point indenter, the difference in the peak-to-valley of the Mises distribution around the Merkel cells indicated 2-point discrimination. Besides, the difference decreased by approximately 43% with changes in skin stiffness. These results indicated that age-related changes in skin stiffness influenced tactile perceptions.

著者

Sandi SUFIANDI Hiromichi OBARA Huai-Che HSU Shin ENOSAWA Hiroshi MIZUNUMA

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Biomechanical Science and Engineering (ISSN:18809863)

巻号頁・発行日

pp.17-00421, (Released:2017-12-04)

参考文献数

34

被引用文献数

1

---

Improving the process of cell injection during hepatocyte transplantation requires an understanding of the causal relationships that shear, direct contact cells with a solid surface, and cell deformation have on cell viability loss. A linear shear model was used to model this loss of cell viability during their movement on a solid surface as part of the injection step of hepatocyte transplantation. Rat hepatocytes were studied under linear shear using two parallel plates, with a ”tight” condition that had a 25 μm gap, and a ”loose” gap condition with a > 25 μm gap, to determine the effects of cell deformation, and simulate cell viability loss during injection. Cell morphology and deformation were also observed using time-lapse images. Direct contact with a solid surface is deleterious for cells, and live cells became deformed under shear stress until they lost viability. The cell size could decrease or increase during deformation, and a loss of viability could occur due to a loss of membrane integrity or cell rupture. The space limitations in the tight gap could prevent cell expansion, which delayed the process of cell viability loss. In summary, preventing the direct contact of hepatocytes with a solid surface is recommended to improve the cell injection process during transplantation.