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application/pdf, 論文(Article), Objective Magnetoencephalography (MEG) recordings were performed to investigate the cortical activation following tactile-on and tactile-off stimulation. Methods We used a 306-ch whole-head MEG system and a tactile stimulator driven by a piezoelectric actuator. Tactile stimuli were applied to the tip of right index finger. The interstimulus interval was set at 2000 ms, which included a constant stimulus of 1000 ms duration. Results Prominent somatosensory evoked magnetic fields were recorded from the contralateral hemisphere at 57.5 ms and 133.0 ms after the onset of tactile-on stimulation and at 58.2 ms and 138.5 ms after the onset of tactile-off stimulation. All corresponding equivalent current dipoles (ECDs) were located in the primary somatosensory cortex (SI). Moreover, long-latency responses (168.7 ms after tactile-on stimulation, 169.8 ms after tactile-off stimulation) were detected from the ipsilateral hemisphere. The ECDs of these signals were identified in the secondary somatosensory cortex (SII). Conclusions The somatosensory evoked magnetic fields waveforms elicited by the two tactile stimuli (tactile-on and tactile-off stimuli) with a mechanical stimulator were strikingly similar. These mechanical stimuli elicited both contralateral SI and ipsilateral SII activities. Significance Tactile stimulation with a mechanical stimulator provides new possibilities for experimental designs in studies of the human mechanoreceptor system.

In this study, we examine the signal detection ability of an array of neurons with intrinsic channel fluctuation. Numerical simulations show that estimation of the input signal from the output spiking activity of the neuronal array is most accurate if a proper amount of channel noise exists. Theoretical calculation of the mutual and Fisher information confirms the effect of the noise-aided information transfer in the array, or the presence of suprathreshold stochastic resonance. These results indicate that the channel noise, which induces response variability, may play an essential role in population coding.

[Purpose] We aimed to obtain the mean values for physical function tests in healthy community-dwelling people aged 50-79 years and to compare these values between age decades. [Subjects and Methods] We recruited 172 healthy community-dwelling people, who provided their written consent. Grip strength (GS), isometric knee extension torque (IKET), and the times for performing the sit-to-stand test (STS) and timed up-and-go test (TUG) were used as indicators of physical function. Maximum force (Fmax) and maximum power (Pmax) were measured by asking the subjects to perform the counter-movement jump on a force platform system. The mean values were calculated and compared between different age decades by one-way analysis of variance. [Results] In men, all the measurements showed significant differences among different age decades; moreover, GS, IKET, Fmax, and Pmax decreased, while the time required for performing the STS and TUG increased with age. In women, GS, IKET, Fmax, and Pmax decreased, while the time required for performing the TUG increased with age. However, the time required for performing the STS did not differ across age groups in women. [Conclusion] The target values for physical function tests in people aged 50-79 years were established, and they were found to change with age.

During the development of walking, toddlers with Down syndrome (DS) and typical development (TD) face challenges controlling muscles, joints, and body segments. Toddlers with DS have additional challenges including increased joint laxity and decreased muscle tone and show delayed walking onset; the underlying activity of the neuromotor system remains unclear. Here we investigated the emergence of muscle activity from walking onset through 6 months of practice in eight toddlers with DS and eight with TD. We monitored the activity of core gait muscles and motion of leg segments as toddlers walked at their self-selected speeds. At walking onset muscle bursts were frequent with inconsistent burst durations. Over time, both groups of toddlers began to activate their leg muscles by using energy-efficient strategies: decreased muscle burst frequency (Wilks' Lambda=0.364, F(12, 103.476)=4.009, p.001) and increased muscle burst duration (Wilks' Lambda=0.346, F(12, 71.727)=2.946, p= .002). Toddlers with TD increased normalized inter-burst intervals over time but toddlers with DS decreased these interval durations. By 6 months of experience toddlers with TD showed an efficient synergy among muscles, allowing increased relaxation time between bursts. Toddlers with DS improved the rhythmicity of their muscle burst, sustaining longer bursts but timing remained inconsistent. We propose increased muscle burst duration in toddlers with DS may add control by stabilizing their lax joints. Thus, their similar yet different emergent strategy may reflect their unique biomechanical and neurophysiological constraints and represent an efficient control strategy.

In order to understand characteristics of low-frequency motions of ships moored inside ports and harbors, analysis on actual cargo handling logbook of stevedoring services company, including events of interruption of cargo handling, and countermeasure for ship mooring problems are investigated by field observations at two ports and numerical simulation on moored ship motions. First model port concerns with interruption of cargo handling due to the low-frequency motions. Second model port relates to a resonant effect of long-period waves or harbor oscillations, and its countermeasure by mooring system. From the investigation, it is confirmed that the low-frequency motions of ships are induced by a resonance between surge motions and long-period waves or harbor oscillations and an asymmetry in the mooring system, and affect safe ship mooring and operation efficiency of cargo handling in ports and harbors significantly.

The ship motions moored along quay wall depend on external forces such as waves and wind, ship's hull form, mooring system such as fender and mooring line, and structural type of quay wall. In this...

Ship berthing and mooring monitoring system by using pneumatic-type fenders has been proposed. This system consists of present berth monitoring system including a mooring line load monitoring system, and a fender load monitoring system. The fender loads such as fender deflection and reaction force are calculated by measuring inner air pressure of the pneumatic fenders, which have unique characteristics in performance. Furthermore both loads for the mooring lines and the fenders can be used to estimate moored ship motions simultaneously. Total ship monitoring system at jetty can be achieved and contributes safe ship berthing and mooring.

Background and Purpose The authors propose that preadolescents with Down syndrome (DS) initially adapt to contexts that challenge their stability by increasing stiffness and impulse but, with practice, they will continue to adapt, but in the opposite direction, by decreasing stiffness and impulse. The purpose of this study was to explore changes in stiffness and impulse values of participants with DS after sufficient, task-specific practice distributed over time in a motivating environment. Subjects Eight preadolescents with DS and 8 preadolescents with typical development (TD) participated. Methods At pretest and posttest visits, participants walked over ground at their preferred speed and on a treadmill at 40%, 75%, and 110% of their over-ground speed. Practice included 4 sessions of treadmill walking at 75% of over-ground speed for 12 minutes, with approximately 800 strides per leg per session. Results The preadolescents with DS had reduced stiffness and impulse values following walking practice while still producing kinematic patterns uniquely different from those of their peers with TD. Discussion and Conclusion Preadolescents with DS can adjust their dynamic resources, both upward and downward. With practice, they can maintain stability while improving efficiency, producing stiffness and impulse values more like those of their peers with TD.

Although women reportedly have a higher prevalence of medial tibial stress syndrome (MTSS) than men, the possible role of gender-based anatomical differences has not been investigated. The aim of the present study was to investigate the presence of gender-based differences in the range of muscle attachments along the entire medial tibia, the proportion of muscle attachment at the middle and distal thirds of the medial margin of the tibia, the structure of the crural fascia, and chiasm position. The specimens were 100 legs of 55 Japanese cadavers. Statistical analysis was carried out using a chi-square test to compare anatomical features between the sexes. The flexor digitorum longus (FDL) had a higher proportion of attachment to the middle and distal thirds of the medial margin of the tibia than the soleus (SOL; P

Task-specific actions emerge from spontaneous movement during infancy. It has been proposed that task-specific actions emerge through a discovery-learning process. Here a method is described in which 3-4 month old infants learn a task by discovery and their leg movements are captured to quantify the learning process. This discovery-learning task uses an infant activated mobile that rotates and plays music based on specified leg action of infants. Supine infants activate the mobile by moving their feet vertically across a virtual threshold. This paradigm is unique in that as infants independently discover that their leg actions activate the mobile, the infants' leg movements are tracked using a motion capture system allowing for the quantification of the learning process. Specifically, learning is quantified in terms of the duration of mobile activation, the position variance of the end effectors (feet) that activate the mobile, changes in hip-knee coordination patterns, and changes in hip and knee muscle torque. This information describes infant exploration and exploitation at the interplay of person and environmental constraints that support task-specific action. Subsequent research using this method can investigate how specific impairments of different populations of infants at risk for movement disorders influence the discovery-learning process for task-specific action.

Objective: Backward stair descent has attracted attention from the viewpoint of injury prevention. Previous studies have shown that knee extension moment is lower during the backward stair descent than during the forward stair descent. However, it remains unclear whether the bone-on-bone force at the tibiofemoral joint differs between the two stair descent methods. The purpose of this study was to estimate bone-on-bone forces at the tibiofemoral joint during forward and backward stair descent. Methods: Six healthy young men participated in this study. The stair descents were performed in the forward and backward direction using a step-by-step pattern. The muscle tensions of the lower limbs were estimated based on the net joint moments and information provided by the electromyography. The bone-on-bone forces at the tibiofemoral joint were calculated based on the estimated muscle tensions and geometry of limbs. Results: While the knee extension moments were significantly lower during backward stair descent than forward stair descent, the estimated bone-on-bone forces at the tibiofemoral joint in two different descending methods showed no significant difference. The quadriceps femoris tension during backward stair descent was significantly lower than that during forward stair descent. Conclusions: The bone-on-bone forces reflect mechanical load to the articular surface. Thus, the results of this study suggested that the load of tibiofemoral articular surface remains unchanged between the forward and backward stair descent. However, backward stair descent might be a relevant method for reduction of quadriceps femoris tensions.

In this study, we investigated biomechanical contributions of the high guard position of the arms observed only in a subgroup of toddlers at very early stages of gait development. Six healthy toddlers who showed this peculiar arm posture were involved in this study. They participated in two data collection sessions (1 month apart). We used three-dimensional analysis of arm posture during gait to estimate the changes in forces and torques generated by the arms and acting on the upper trunk segment. Across visits, toddlers' increase in walking speeds coincided with lowering arm postures. Despite the apparent trend of changes in arm posture in this group of toddlers, the interaction between arm posture and upper trunk position created a variety of changes in forces and torques among individuals. Findings of this study exhibited an example of the exploration of dynamics by toddlers in the early stage of gait development.

In human biped gait, movements in the frontal plane such as side-to-side rocking, are as essential as the alternating movement of the legs in the sagittal plane. In addition, the top-heavy structure of human body necessitates control of the trunk during walking. In this study, we evaluated the pelvis and HAT (head, arms and trunk) movements and their coordination during treadmill walking in the anterior-posterior and medio-lateral directions in children with typical development (TD) and those with Down syndrome (DS). Participants were 12 children with DS aged 8-10 years and 10 age-matched children with TD. They walked on a treadmill at 40%, 75% and 110% of their preferred overground walking speeds. Kinematic data were collected using a 3D-motion-capture system; movements of the mid-point of hip joints (OPELVIS) and the center of mass of HAT (COMHAT) were reduced. Children with DS showed larger and speed dependent amplitude responses compared to their TD peers. Coordination patterns for children with DS were less stable, especially in medio-lateral direction at slow speed. Differences in amplitude response may be the result of poorer trunk control in children with DS or, alternatively, part of a necessary and sufficient propulsion/stabilization mechanism for this population with reduced tone and muscle strength. Response differences observed between the anterior-posterior and medio-lateral directions for both groups may reflect relative differences in the involvement of active neuromuscular control.

The authors examined the changes in bipedal gait of toddlers in the anteroposterior (AP) and mediolateral (ML) directions, as a set, at the onset of independent gait and 1 month after onset. Two groups with distinctly different dynamic resources were studied: 8 toddlers with typical development (TD) and 8 toddlers with Down syndrome (DS). Three-dimensional kinematic data were collected, and gait parameters, such as walking speed, stride length, and stride frequency, as well as the ratio of exchange between potential energy and kinetic energy of the center of mass (COM), were calculated. Displacement of the COM in the AP and ML directions were also analyzed. For some gait variables, toddlers with DS seemed to show more mature values at walking onset than their peers with TD. Those group differences reversed and increased by Visit 2. When the authors considered the motion of the COM of the system, it became clear that the qualitative differences between those groups were characterized primarily by constraints in the ML direction. The authors propose that establishment of coupling between AP and ML oscillations is a key component for the emergence of independent bipedal walking for both populations.

The authors investigated the self-selected, overground walking patterns of 7 children (aged 11 months to 1 year, 5 months) at the initiation of walking (brand-new walkers [BNWs]) and for the next 6 months at 1-month intervals. Walking speed, stride length, and stride frequency increased significantly between the first 2 visits without significant changes in height and weight. The authors calculated sagittal plane angular accelerations of the center of mass over the foot for each step as an indicator of the escapement pulse. Results for the acceleration profiles changed after the 1st visit to positive, single-peaked accelerations that occurred < 0.20 s after initial foot contact. Increases in sagittal plane hip angular displacement and decreases in frontal plane pelvic angular displacement were observed. The pattern changes suggest that children quickly discover appropriately timed and directed escapements that initiate and support the conservative sagittal plane pendulum and spring dynamics observed in older children.

Research suggests that abnormal coordination patterns between the thorax and pelvis in the transverse plane observed in patients with Parkinson's disease and the elderly might be due to alteration in axial trunk stiffness. The purpose of this study was to develop a tool to estimate axial trunk stiffness during walking and to investigate its functional role. Fourteen healthy young subjects participated in this study. They were instructed to walk on the treadmill and kinematic data was collected by 3D motion analysis system. Axial trunk stiffness was estimated from the angular displacement between trunk segments and the amount of torque around vertical axis of rotation. The torque due to arm swing cancelled out the torque due to the axial trunk stiffness during walking and the thoracic rotation was of low amplitude independent of changes in walking speeds within the range used in this study (0.85-1.52 m/s). Estimated axial trunk stiffness increased with increasing walking speed. Functionally, the suppression of axial rotation of thorax may have a positive influence on head stability as well as allowing recoil between trunk segments. Furthermore, the increased stiffness at increased walking speed would facilitate the higher frequency rotation of the trunk in the transverse plane required at the higher walking speeds.

To provide reference values of muscle function (MF) and mobility performance (MP) and to clarify the effects of MF on MP.A normative cross-sectional study.An urban area of Niigata, Japan.A total of 401 individuals (210 men and 191 women) with a mean age of 41.8 years (range, 7-79 years) who lived in the community and did not have impairments in activities of daily living.Grip strength, isometric knee extension torque (IKET), and maximum ground reaction force (Fmax) and maximum power (Pmax) during a vertical jump were used as measurements of MF. The chair-rise test (CRT) and the timed "Up and Go" test (TUG) were used to assess MP.Mean values of GS, IKET, CRT, TUG, Fmax, and Pmax were calculated according to age and gender. A stepwise multiple regression analysis was used to identify MF factors with an effect on CRT and TUG in participants ≥20 years of age.Our results showed that all MF parameters were decreased in individuals ≥20 years of age compared to those20 years old. Moreover, all of the MP parameters increasingly deteriorated with increasing age. CRT and TUG were affected by Pmax and IKET in men and by IKET in women according to logistic regression analysis.The study findings suggest that muscle power affects MP more than the muscle strength in persons aged ≥20 years.

Five healthy male subjects walked on a control surface (level concrete), and two sloped rock surfaces (walking ballast-rock about 1.9 cm across; main line ballast-rock about 3.8 cm across) while their rearfoot motion (defined throughout as ankle inversion/eversion as seen from the frontal plane) was measured to determine if the different walking surfaces caused different ankle kinematics. The ballast was placed in 5m long trays that were tilted 7 degrees in the transverse plane. Rearfoot motion was measured while the subjects walked the length of the respective surfaces wearing work boots. A repeated measures ANOVA and a subsequent multiple comparison test revealed that the rearfoot range of motion was significantly greater walking on the main line ballast than walking on either the walking ballast or the level concrete. Meanwhile, the mean range of rearfoot motion for walking ballast was not significantly different from that resulting from walking on concrete. Variability was more than twice as great walking on main line ballast than walking on level concrete. Rearfoot angular velocities walking on level concrete and walking ballast were not significantly different, but both were significantly less than walking on main line ballast. Results suggested that rearfoot motion could be reduced if railroads placed walking ballast where trainmen have to walk as part of their jobs. Language: en

This study was designed to investigate the capability of the joints and segments to reduce transmission of forces during load carriage. Eleven subjects were required to carry a backpack loaded with 40% of their body weight and to walk at 6 speeds increasing from 0.6 to 1.6 m s −1 in increments of 0.2 m s −1 , and then decreasing in the same manner. Subjects were filmed in 3-dimensions, but analysis of shock transmission ratio (TR) was limited to the sagittal plane. Shock transmission was measured as the ratio of peak vertical accelerations (ankle:head, ankle:knee, and knee:head) measured immediately following foot strike. TR for all ratios increased significantly as a function of increasing speed. TR from the ankle to the head showed no significant increase as a function of load carriage, but did increase as a function of load in transmission from knee to head. A significant interaction effect revealed that during load carriage at the higher speeds the acceleration of the ankle and knee decreased below that for the unloaded conditions. These findings suggest that the potentially injurious effects of previously observed increased ground reaction forces and increased joint stiffness while walking with loads are offset by adaptations in the gait pattern that maintain force transmission at acceptable levels. Increased variability in the acceleration of the head and in the transmission ratios suggest a potentially destabilizing effect of load carriage on the head trajectory.

Planning for the construction of ports and harbors usually takes place without the consideration of tsunamis because of their rare occurrence, approximately once every 100 years. However, recent warnings indicate that massive earthquakes could occur in Japan within the next 30 years. Earthquakes may generate large-scale tsunamis. Therefore, any tsunamis in the vicinity of Japan would also be expected to affect eastern Korea. Therefore, with the looming concerns of tsunamis and earthquakes, immediate attention must be given to the planning of ports and harbors. The warnings deserve an immediate response. The threatened regions cover a very large territory, and the degree of severity of the tsunamis is forecasted to be varied. Therefore, any modeling of the potential scenarios will require a broad array of possibilities. The objective of this paper is to consider the potential damage from tsunamis to ports and moored ships in Japan and Korea. In addition, consideration will be given to how the construction plans of ports and harbors should be changed to cope with the threats from earthquakes and tsunamis.

In Jensen's theme paper she did an excellent job of outlining and explaining ways in which motor developmentalists can use the tools of biomechanics and engineering to address research questions. We extend her thorough efforts in two ways. First, we highlight the communication value provided by the precision of biomechanics terminology, and second, we reinforce the need to embed motion (the kinematics and kinetics) in context and function in order to understand the complexity of behaviour. We illustrate how one biomechanical tool, mechanical models, can facilitate this and provide insight to the development of control. Copyright © 2005 John Wiley & Sons, Ltd.

In this study we used a damped inverted pendulum and spring with an escapement function model to compare the global levels of stiffness and forcing used by 12 preadolescents with Down syndrome (DS) and 12 with typical development (TD). Participants walked overground at their self-selected speed and on a treadmill at speeds slower and faster than overground. Children with DS, who are characterized as hypotonic with reduced capacity for producing muscle force, exhibited significantly higher levels of stiffness and forcing (angular impulse) when walking on the treadmill and higher forcing but not stiffness overground, than children with TD. Both groups adapted to imposed speed increases similarly by increasing their global stiffness and angular impulse. We propose children with DS increased stiffness in order to overcome their hypotonia and joint laxity, thus, optimizing on stability, rather than metabolic efficiency. Higher angular impulse values for children with DS may reflect higher energy cost associated with increasing stiffness and their inherent biomechanical and physiological characteristics that reduce efficiency. We conclude that the inverted pendulum and spring with escapement function model is a useful tool for uncovering solutions to movement problems-solutions that reflect the dynamic resources of the individual and ones that are discovered, rather than prescribed.

As humans increase walking speed, there are concurrent transitions in the frequency ratio between arm and leg movements from 2:1 to 1:1 and in the phase relationship between the movements of the two arms from in-phase to out-of-phase. Superharmonic resonance of a pendulum with monofrequency excitation had been proposed as a potential model for this phenomenon. In this study, an alternative model of paired pendulums with multiple-frequency excitations is explored. It was predicted that the occurrence of the concurrent transitions was a function of (1) changes in the magnitude ratio of shoulder accelerations at step and stride frequencies that accompany changes in walking speed and (2) proximity of these frequencies to the natural resonance frequencies of the arms modeled as a pair of passive pendulums. Model predictions were compared with data collected from 14 healthy young subjects who were instructed to walk on a treadmill. Walking speeds were manipulated between 0.18 and 1.52 m/s in steps of 0.22 m/s. Kinematic data for the arms and shoulders were collected using a 3D motion analysis system, and simulations were conducted in which the movements of a double-pendulum system excited by the accelerations at the suspension point were analyzed to determine the extent to which the arms acted as passive pendulums. It was confirmed that the acceleration waveforms at the shoulder are composed primarily of stride and step frequency components. Between the shoulders, the stride frequency components were out-of-phase, while the step frequency components were in-phase. The amplitude ratio of the acceleration waveform components at the step and stride frequencies changed as a function of walking speed and were associated with the occurrence of the transitions. Simulation results using these summed components as excitatory inputs to the double-pendulum system were in agreement with actual transitions in 80% of the cases. The potential role of state-dependent active muscle contraction at shoulder joints on the occurrence of the transitions was discussed. Due to the tendency of arm movements to stay in the vicinity of their primary resonance frequency, these active muscle forces were hypothesized to function as escapements that created limit cycle oscillations at the shoulder's resonant frequency.

Mooring problems are still serious issues in port construction and operation. Although many studies have been carried out about moored ship motions or waves, effective countermeasures to reduce ship motions have not been accomplished in most harbours facing open seas. It is known that operators require detailed wave information near harbours when sea conditions become severe. In this study, a new numerical model is constructed for the prediction of the mooring limit condition due to typhoons. It is based on the theories of Kalman Filter, wave growth inside typhoons and wave decay in swells. The prediction model needs less input data than the meteorological models. The accuracy of the predicted model is verified for a port facing the Pacific Ocean when swells or wind waves propagate from typhoons in various situations. The prediction model is applied to other locations facing the Pacific Ocean. This new model allows us to predict the mooring limit condition 0.5–2 days before the influence of typhoons. More...

We attempted to estimate the pharmacological activity by measuring the concentrations of a composition ingredient using a multivariate statistical analysis method. Medicinal herb of Rhubarb has been many largely unrecognized biochemical and pharmacological effect components. Therefore, we attempted to estimate the antioxidative activity of Rhubarb on low-density lipoprotein (LDL) of its components. Thirty specimens of Rhubarb from various origins were used, chose nine components of anthraquinones, two components of anthrones, two components of flavan-3-ols, one component of procyanidin, one component of naphthalene, two components of phenylbutanones and one component of stilbene. Quantitative analysis of 18 components was performed with high-performance liquid chromatography (HPLC) and antioxidative activities were measured with plasma taken from spontaneous familial hypercholesterolemia model rabbits. There was considerable variation among the specimens in the concentration of components and antioxidative activities on LDL. As a result of multiple regression analysis, significant multiple correlation coefficient for antioxidative activities on LDL (R=0.914, P

In 2025, it is predicted that about 5 billions of people all over the world will face water shortage. In the case of Japan, on the other hand, it is thought that there are enough water resources in Japan. However, water is necessary not only for our daily life but also for the agricultural use. Considering these facts, it have come to clear that Japan actually imports a lot of water, about half of the needs. Therefore, effective uses of water resources are studied for the isolated islands such as Sakishima island, Okinawa, where water supply is almost constantly in iill-condition.Water resources are transported to the water-shortage isolated islands from other area where rhere are enough water by the use of MEGA-BAG made of fiber-reinforced rubber and stored in reservoir there. This constant supply of water resources would encourage the agricultural economy in this area. The possibility for the generation of electricity by the use of wind force and biomass was also examined.The keys technology for this study is the optimum design and manufacture of rubber materials.

Kampo formulations are traditional herbal medications used in China and Japan for many centuries to treat diarrheal diseases such as cholera. Our studies were undertaken to identify and verify by chemical synthesis the active components that inhibited cholera toxin (CT), the virulence factor secreted by Vibrio cholerae , the causative agent of cholera. The Kampo formulation, Daio-kanzo-to, inhibited CT activities (i.e., ADP-ribosylation, Chinese hamster ovary cell elongation); in Daio-kanzo-to, Daio ( Rhei rhizoma ) was responsible for this effect. Among several components purified from Daio extract, rhubarb galloyl-tannin, a compound characterized by a polygallate structure, was the most effective. To define the active component, gallate analogues similar to rhubarb galloyl-tannin were synthesized. These gallate compounds inhibited all CT activities including ADP-ribosylation, elongation of Chinese hamster ovary cells, and importantly, fluid accumulation in ileal loops. Thus, Kampo formulations or their gallate components might be effective adjunctive therapy with oral rehydration solution for the severe diarrhea of cholera.