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BACKGROUND: Individuals with gait disturbances, such as that post-stroke, are discharged home to undergo outpatient rehabilitation. Rehabilitation in the community is not as effective as that in hospital, due to long travel times and short program duration. OBJECTIVE: This study analyzed rail unit structure, with the aim of assisting home indoor assistive mobility system (HIAMS) development, allowing patients to undergo gait-related rehabilitation training at home. METHODS: The HIAMS consists of a mobile rail running around the whole room, a turn-table for movement between rails, and a weight-supporting component. Structural analysis was performed using the Abaqus/CAE solution (Version 6.14, Dassault systems, Inc.) to verify device safety, according to the load applied to the rail and turn-table units. The load was applied vertically at 150 kg to reflect the weight of potential users. RESULTS: Structural analysis was performed on the weight-supporting components, which was consist of turn-table case, bearing components (center, left), connective bracket and rail rollers. The safety factors of each components were estimated as 1.31, 5.39 (bearing, center), 8.45 (bearing, left), 1.43 and 3.61 in sequence. CONCLUSION: We demonstrated a safety factor of ⩾ 1.3 for the key system units, suggesting this technology is safe for use in the home rehabilitation training of individuals with gait impairment post-ICU stay.

To accurately predict and monitor an individual’s health, accurate information on the changing patterns of the individual’s physiological signals is required. In this study, obesity parameters were analyzed using regression analysis based on the physiological signals of individuals who performed continuous exercise. To this end, three healthy adult subjects participated in the experiment, and their health management was analyzed by monitoring changes in health information parameters while they performed continuous exercise with daily activities over a long period of time. Subjects’ exercise parameters included heart rate were collected through smart watches, and their specified obesity parameters were measured using a smart scale. The analysis results showed that weight and body fat decreased and muscle composition increased in conjunction with the amount of exercise for two subjects who performed continuous exercise while conducting daily activities. For one subject who did not perform any specific exercise, however, the weight and body muscle rate tended to increase slightly and the body fat rate tended to decrease slightly. It was found that continuous exercise improved the subjects’ ability to adapt to exercise, thereby increasing Max BPM and reducing weight. Performing continuous exercise while conducting daily activities appears to improve physical measures of health, as it decreases weight and body fat rate and increases body muscle rate. Health management analysis based on the physiological data collected from smart devices is expected to play a role in keeping the human body healthy.

In this study, a multi-sensor data fusion system using a load cell and vision sensor was considered in the development of a flatfish classifier for systematic fish management in aquaculture. In the single-sensor measurement method, each sensor has disadvantages. A load cell shows high performance in the measurement of adult fish, but the measurement of fry is affected significantly due to water weight (water weight disturbance). A vision sensor shows high performance in the measurement of fry, but the movement of fish (movement disturbance) affects the accurate measurement of adult fish. Therefore, in this study, these disturbances were compensated for using a datafusion algorithm, of which the performance was evaluated by a comparison between single sensor measurements and multi-sensor data fusion results.

This paper proposes the use of a gyrostabilizer to improve the response performance of an unmanned underwater vehicle navigated by a quadrant detector (QD) in shallow water docking operations under the influence of ocean disturbances. Reference tracking and disturbance attenuation were investigated with and without delayed response from the gyroscope. The control methodologies examined are combinations of forward Riccati and passive control, forward Riccati and proportional-derivative (PD) control, and forward Riccati and penalty function control. Forward Riccati control is applied to the yaw-pitch dynamics for command tracking, while gyro-dynamics control for disturbance attenuation is achieved using passive, PD, and penalty function controls. Overall, the forward Riccati and penalty function control method showed desired performance because the gyro-precession workspace was maintained within actuation limits while operating within a region of dominant precession spin or control.

Background With the improvement in the standard of living, there has been increasing interest in facial skin care. In particular, it has been observed that people pay extra attention to eye-skin when they visit skin care parlors for special treatment and care. Objective There is a need for skin care devices that would enable convenient skin care anywhere, including at home and on the move. In this research, we developed a prototype of a glasses-type skin care device with a LED (Light-Emitting Diode) irradiation function and performed injection molding analysis of the skin care device model for mass production. Methods First, the product was designed using a universal design to improve the wearability of the glasses-type skin care device. The first prototype of the skin care device was produced using an integrated LED optical module capable of irradiating at three LED wavelengths to investigate the structural function of the product. The prototype was classified into three mechanisms and injection molding analysis was performed. The fill time, temperature at flow front, injection pressure, clamp force, and deflection values were analyzed according to the appropriate number and location of gates into which the PC + PBT (Polycarbonate + Polybutylene terephthalate) resin was introduced. Results We found that all the other parts except the temple section of the device were inferior in moldability. Conclusion In further studies, the 3D prototype will be modified to enhance moldability, and injection molding analysis with other materials as well as with PC + PBT resin will be performed.

Background Accurate detection of the intended movement direction of a patient plays an important role in the development of a training system for gait rehabilitation and enables to increase the effect of gait rehabilitation training. Objective This study investigated the detection of the intended movement of a user to operate a ceiling rail-based rehabilitative training system with accurate timing. Methods To detect the movement direction intention of a user, two potentiometers were used to measure the movement direction in the anterior, posterior, and left and right directions of the user when operating the driving motor of the rehabilitative training system. A simple test mock-up with two potentiometers was fabricated, and the experiments were conducted to determine the effect of the direction of movement on the measured values of potentiometers. A direction measurement algorithm was developed to control the driving motor of the rail-based gait rehabilitative training system. Results The intended movement direction of the user could be predicted for eight directions by combining the "positive value, 0, negative value" of each measured value of the two potentiometers. Further, the developed algorithm was effectively used to control the driving function to assist the walking, sitting-standing, and climbing up-down the step activities in daily life. Conclusions The movement intention detection function for users developed in this paper can be used to effectively control a rehabilitative training system for patients with hemiplegia to improve gait movement and posture balance, thereby improving their function of activities of daily living.

The hydrogen emission characteristics of a hydrogen storage alloy operating system employing the Zr[Formula: see text]Ti[Formula: see text]Cr[Formula: see text]Fe[Formula: see text] alloy were analyzed under different temperatures and loading conditions for application in a rehabilitation system for motion assistance for the aged and disabled. After activating 8.56[Formula: see text]g of a Zr[Formula: see text]Ti[Formula: see text]Cr[Formula: see text]Fe[Formula: see text] alloy under a 5.5[Formula: see text]MPa hydrogen atmosphere, operation tests were conducted in the temperature range of 25–80∘C under the loading conditions of 5–45[Formula: see text]kg. The lightest load of 5[Formula: see text]kg was lifted by 150[Formula: see text]mm when the system was heated from the initial test temperature of 25–80∘C and a 40[Formula: see text]kg load was lifted by 12.5[Formula: see text]mm at 80∘C, while a 45[Formula: see text]kg load could not be lifted under any of the temperature conditions. The hydrogen storage alloy operating system developed in this study is expected to be useful in motion assistance for the socially underprivileged, as a rehabilitation tool for the hand, wrist, and elbow, as supplementary equipment, and in rehabilitation systems for daily life.

New Jersey (NJ) residents in some areas may be exposed to perfluoroalkyl and polyfluoroalkyl substances (PFAS) due to PFAS contamination of public drinking water. This contamination stems from industrial discharges and the use of aqueous film-foaming foams at military bases and commercial airports for drills and locations where fires occurred. Exposure to PFAS has raised significant public health concerns due to its persistence both in the environment and human body. The potential toxicity of these chemicals may pose risks to human health. Statewide biomonitoring data is needed to establish a baseline of exposure and to identify the subpopulations at risk. The NJ Department of Health (NJDOH) conducted a statewide NJ Biomonitoring (NJBM) study for PFAS utilizing a cost-effective sampling approach, i.e. acquiring remnant sera from both clinical laboratories and blood banks across NJ. This convenience sampling approach was adopted as an alternative to a costly and labor-intensive probability-based population sampling. One thousand and thirty human sera were collected from NJ adults between 20 and 74 years of age from 2016 to 2018, with additional information of county, sex, and age. The serum collection was demographically and geographically dispersed across four seasons. Twelve PFAS analytes were measured for the specimens collected. The data were post-stratified by county, sex, and age groups (20–39, 40–59, and 60–74 years old). Stratified individual sample weights were developed and used to estimate population means, compare least-squared mean differences, and examine contributing variables. Geometric means (GMs) and percentiles with 95% confidence intervals (CIs) of the target analytes are presented, providing preliminary baselines of the statewide PFAS exposure for NJ adults. PFOA, PFNA, PFHxS, and PFOS were selected for in-depth analyses because their GMs were greater than 0.5 ng/mL and they were detected over 99% in study population. Subjects from this study had higher serum levels of PFOA, PFNA, and PFHxS compared to the general U.S. population reported by the latest National Health and Nutrition Examination Survey (NHANES in 2015–2016). However, the distributions of PFOA, PFNA, PFHxS, and PFOS across sex and age groups were consistent with the patterns found in NHANES, i.e. all differed by sex and age group. Further sex and age stratification showed significantly lower concentrations of the 4 analytes in younger females (20–59 years old) than in older females (60–74 years old) and males (20–74 years old). Future research is needed to identify PFAS exposure sources and to develop effective intervention strategies. Continuing PFAS biomonitoring using population sampling is recommended for tracking trends and better identifying subpopulations at risk.

BACKGROUND: Hydrogen has advantages that can be used as energy, but research on safe use is needed. OBJECTIVE: In this study, an actuation system for rehabilitation is developed to drive the actuator using hydrogen storage alloy and to analyze the hydrogen release characteristics of the alloy. METHODS: The system is automatically control and report the pressure, temperature and hydrogen flow using LabVIEW-based modules and LabVIEW software. Zr0.9Ti0.1Cr0.6Fe1.4 alloy was selected as hydrogen storage alloy. 5 MPa of hydrogen pressure was applied at 8.56 g of alloy powder for activation process and the temperature outside was maintained at 19∘C to 21∘C. The amount of hydrogen absorption was measured about 1.47 wt%. The actuation test was conducted at the temperature from 25∘C to 80∘C, increased by every 5∘C. The actuation height was measured at each load of 5, 10, 15, and 20 kg. The voltage and current which is applied to peltier elements were set to 5.0 V and 2.5 A. The pressure changing in the system was checked for 5 min for each temperature, however, if the temperature at which the pressure inside the system changed, the time to heat the module was increased to 20 min. Hydrogen was first released at 70∘C. RESULTS: The loads of 5 and 10 kg were raised by 87 and 19 mm at 70∘C, respectively. At 75∘C, loads of 5, 10 and 15 kg were raised by 131, 70, and 15 mm, respectively. At 80∘C, 5, 10, 15, and 20 kg were raised by 150, the end of the actuator, 83, 55, and 28 mm, respectively. CONCLUSIONS: The actuation system in this paper can be applied to assistive device and rehabilitation system for assisting the movement of daily life of the elderly or people with disability.

Background: Per-and polyfluoroalkyl substances (PFAS), are ubiquitous pollutants associated with adverse health outcomes. High PFAS levels have been demonstrated among career firefighters; less is known about PFAS levels among volunteer firefighters who comprise two-thirds of US firefighters. Methods: Volunteer fire department members completed a survey and provided blood samples. We calculated geometric means and 95% CIs for PFAS reported by the National Health and Nutrition Examination Survey (NHANES). We compared PFAS distribution and levels among non-Hispanic white adult male study participants to those in the 2015–2016 and 2017–2018 NHANES cycles. We assessed associations between PFAS serum levels and years of firefighting controlling demographics and occupation using linear regression. Results: Participant’s average age was 46.6 years (sd. 17.1). Perfluorododecanoic acid (PFDoA) was detected in almost half study but

Background Hydrogen storage using metal hydride (MH) offers various advantages so the global research and development using MH alloys keeps growing. Objective In this paper, we developed a new actuation system using temperature control of the MH module. Methods The actuation system consisted of an MH module, fan, mass flow controller (MFC), solenoid valve, actuator, and a temperature and pressure sensor. The MH module, two fans and temperature sensors were set for heating and cooling the MH power by electricity. Two MFCs and four pneumatic solenoid valves were used for controlling the direction and measuring hydrogen flow. Two actuators were used to evaluate performance of the MH alloy, and all the results were measured by LabVIEW software. Hydrogen was absorbed by the MH alloy by pressurizing at 1 MPa, and the absorbed hydrogen was desorbed using a vacuum pump. Results The temperature condition of the driving test was 20-50∘C. As the module was heated, it was confirmed that the actuator connected to the system was driven by the pressure of desorbed hydrogen. Conclusion It is confirmed that the actuation system is suitable for the evaluation of characteristics of MH alloy. Future studies are planned to develop MH alloys and test the actual driving performance using this system.

The body weight support (BWS) system that allows a patient to support his or her body weight in step-wise fashion, depending on their physical condition, is an important intervention that assists individuals with gait disabilities in their gait rehabilitation. In this paper, we measured human body signals in order to verify a rehabilitation system using active harness that we developed for gait and balance training based on ceiling-rail platform. 20 healthy participants were performed to conduct daily activities related to lower limbs. They did a kind of motions related to daily life (Normal Walking, Stand-to-Sit, and Stair Walking Down) according to variation of body weight support rates (0%, 30%, 50% of subject’s body weight). The effectiveness of the weight supporting on healthy people is analyzed by the muscular activities and foot pressure distribution. In normal walking, the decrease of fore-foot pressure, lateral soleus muscle and biceps femoris muscle were remarkable. The result of stand-to-sit results motion indicated that the rearfoot pressure and tibialis anterior muscle activities exceptionally decreased according to body weight support. The stair walking down results indicate the marked drop of fore-foot pressure and rectus femoris muscle activities. Based on these results, a function of weight supporting is very helpful to improve the gait ability of people with gait disorder.

BACKGROUND: A lightweight rehabilitation assisting system is required to help the aged and disabled with daily life activities, thereby improving the quality of their lives. OBJECTIVE: This paper discusses the development of a metal-hydride (MH) actuator, with excellent heat transfer performance, for application in a rehabilitative system incorporating an MH module. METHODS: The operating mechanism of MH actuators requires that the mechanical power of the pneumatic actuator only be generated via heat transfer through a Peltier element and the absorption/desorption of a hydrogen-contained MH module. To achieve this aim, a 3D model was first designed for two MH modules, and a thermal analysis was carried out according to the type of contact with the Peltier elements to fabricate an MH module with improved heat transfer performance. LabVIEW (National Instruments) was used for automatic temperature control of the Peltier element in the MH actuator driving experiment. Zr0.9TI0.1Cr0.6Fe1.4, which yields a pressure-composition-temperature (PCT) curve of appropriate pressure and temperature ranges for a rehabilitative system, was selected as the hydrogen-absorbing alloy. RESULTS: In addition, the temperature conditions of the MH actuator driving experiment were restricted by two temperature control ranges (30–40∘C/30–50∘C) of the Peltier element. Within these Peltier element temperature ranges of 30–40∘C and 30–50∘C, results showed that the MH actuator was driven in the ranges of 2–3 atm and 2.5–3.5 atm, respectively. CONCLUSIONS: These findings indicate that the MH actuator proposed in this paper can be utilized to drive a rehabilitative system for elbow and knee joint exoskeletons.

This paper presents a wireless active finger rehabilitation method controlled magnetic forces within a three-axis coil system. The three-axis coils enhanced degree of freedom in hand positioning. The developed system includes three magnets for controlling one finger within the coil, thus, providing external force to the finger without the use of a complex mechanical structure. The proposed method is simple in configuration and operates wirelessly by magnetic interaction. The system generates three magnetic forces for flexion and extension of the finger. The proposed method can be used regardless of the position of the hand in the system. The combined influence of the three magnetic forces used to generate flexion and extension of the finger was verified through experimental analysis.

This study was to provide independent exercise loads in rowing exercise machine, on the improvement of muscle strength imbalance. We recruited twenty four subjects who exhibited one side's muscle strength is bigger in more of greater than 20% than other on one side. One group was dominant left side and the other group was dominant right side. Subjects performed the rowing exercise in electric load deviation rowing machine (Robo.gym, Humonic Co., Ltd, Daegu, Korea). The exercise was progressed to four sets a day including twenty five repetitions per set, and three days a week, for a total of eight weeks. Measurements consist of evaluation of muscular activity, joint torque in the elbow, shoulder. Exercise load deviation adapted that difference value of muscle strength between left and right side arms multiply 1RM% and its plus 1-RM 75% in each side. The result showed that the level of muscle imbalance significantly decreased in shoulder and elbow joint by adapting exercise load deviation. We found out that exercise load deviation provided to the positive effect both muscle strength and endurance at the same time. As a result of this study, rowing exercise using the exercise load deviation is effective in improving muscle strength imbalance.

Objective In this paper, we investigated the recovery of the lactate level, muscular fatigue, and heart rate recovery (HRR) with respect to whole body vibration (WBV) during the rest stage after a gait exercise. Methods A total of 24 healthy subjects with no medical history of exercise injury participated. The participants were divided into a training group with vibration during rest and a control group with the same conditions but without vibration. The subjects performed a gait exercise with a slope of 15% and velocity of 4 km/h to consume 450 kcal in 30 min. Then, they rested on a vibrating chair or on a chair without vibrations for 30 min. The vibration protocol consists of a frequency of 10 Hz and amplitude of 5 mm. To estimate the recovery effect, we measured the lactate levels in blood, spectral edge frequency (SEF) of MVIC, and HRR before, immediately after exercise, and after rest. Results The results showed that the lactate level in the training group decreased more (93.8%) than in the control group (32.8%). Also, HRR showed a similar trend with a recovery of 88.39% in the training group but 64.72% in the control group. We considered that whole-body vibrations during rest would help remove lactic acid by improving the level of lactic acid oxidation with stimulated blood vessels in the muscles and by helping to maintain blood flow. Also, WBV would lead to compensation to actively decrease the fast excess post-exercise oxygen consumption from blood circulation. Conclusions We suggest that whole-body vibrations during rest can provide fast, efficient fatigue recovery as a cool down exercise for women, the elderly, and patients without other activity after intense exercise.

Elevated perfluorononanoic acid (PFNA) levels, one of many manmade per- and polyfluoroalkyl substances (PFAS), were detected in public water systems/private wells in New Jersey communities. Interventions to end exposure through drinking water were carried out from 2014 to 2016. To evaluate the effectiveness of interventions, a community biomonitoring study was conducted for the communities between 2017 and 2020. A convenience sampling design was used with 120 participants in Year 1 between ages of 20–74 who consumed PFNA-contaminated water. Three blood samples, one year apart, were drawn from each participant and completed for 99 participants. Separated serum samples were measured for 12 PFAS including PFNA. Questionnaires were administered to collect information on demographics and potential sources. Drinking water and house dust collected at the first visit were analyzed for 14 PFAS including PFNA. The PFNA sera levels (Year 1) found 84 out of 120 (70%) participants were higher than the 95th percentile of a nationally representative sample of US adults (NHANES2015-16). Current drinking water and house dust were not significant contributing sources for the study participants. On average, PFNA sera levels were 12 ± 16% (Year 2) and 27 ± 16% (Year 3) lower than the level measured in Year 1 (p 95th percentile of NHANES2015-16) with controlling for physiological covariates. The decline in adult serum PFNA levels seen in the years following a community drinking water intervention suggests the intervention effectively reduced PFNA exposure via drinking water.

A selective, sensitive, and accurate analytical method for the measurement of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in human serum, utilizing LC-MS/MS (liquid chromatography-tandem mass spectrometry), was developed and validated according to the Centers for Disease Control and Prevention (CDC) guidelines for biological sample analysis. Tests were conducted to determine the optimal analytical column, mobile phase composition and pH, gradient program, and cleaning procedure. The final analytical column selected for analysis was an extra densely bonded silica-packed reverse-phase column (Agilent XDB-C8, 3.0×100mm, 3.5μm). Mobile phase A was an aqueous buffer solution containing 10mM ammonium acetate (pH=4.3). Mobile phase B was a mixture of methanol and acetonitrile (1:1, v/v). The gradient program was programmed by initiating a fast elution (%B, from 40 to 65%) between 1.0 and 1.5min, followed by a slow elution (%B: 65-80%) in the period of 1.5-7.5min. The cleanup procedures were augmented by cleaning with (1) various solvents (isopropyl alcohol, methanol, acetonitrile, and reverse osmosis-purified water); (2) extensive washing steps for the autosampler and solid phase extraction (SPE) cartridge; and (3) a post-analysis cleaning step for the whole system. Under the above conditions, the resolution and sensitivity were significantly improved. Twelve target PFASs were baseline-separated (2.5-7.0min) within a 10-min of acquisition time. The limits of detection (LODs) were 0.01ng/mL or lower for all of the target compounds, making this method 5 times more sensitive than previously published methods. The newly developed method was validated in the linear range of 0.01-50ng/mL, and the accuracy (recovery between 80 and 120%) and precision (RSD

This paper presents a new multifunctional active guidewire system for medical applications that uses a magnetic microrobot. The study demonstrated that the proposed microrobot system could swim and be controlled under Low-Reynolds-number (Re) environments in blood vessel models. The prototype of the robotic guidewire, which is driven within a three-axis Helmholtz coil system, consists of a guide-wire, spiral blade, drilling tip, and permanent magnet. The spiral-type microrobot showed stable active locomotion between 3 kA/m and 9.1 kA/m under driving frequency up to 70 Hz in a silicone oil (of viscosity 1000 cst). The microrobot produced a maximum moving velocity of 8.08 × 10 −3 m/s at 70 Hz and 9.1 kA/m. In particular, the robotic guidewire produced 3D locomotion with drilling in the three-axis Helmholtz coil system. We verified active locomotion, towing of guidewire, steering, and drilling of the proposed robotic guidewire system through experimental analyses.

Air concentrations of traffic-related air pollutants (TRAPs) vary in space and time within urban communities, presenting challenges for estimating human exposure and potential health effects. Conventional stationary monitoring stations/networks cannot effectively capture spatial characteristics. Alternatively, mobile monitoring approaches became popular to measure TRAPs along roadways or roadsides. However, these linear mobile monitoring approaches cannot thoroughly distinguish spatial variability from temporal variations in monitored TRAP concentrations. In this study, we used a novel mobile monitoring approach to simultaneously characterize spatial/temporal variations in roadside concentrations of TRAPs in urban settings. We evaluated the effectiveness of this mobile monitoring approach by performing concurrent measurements along two parallel paths perpendicular to a major roadway and/or along heavily trafficked roads at very narrow scale (one block away each other) within short time period (

This study intends to develop a system for managing the health of the spinal joints of elderly people who mainly live on Korean floor heating (Ondol). The spine health management system consists of a seat cushion-type posture balance device that can measure the sitting posture, an application for smart devices capable of real-time collection of posture balance data, and a database server for analysis and visualized feedback of the data. Each force signal measured with the four load cells installed in posture balance device is wirelessly transmitted to an Arduino-based Android application, and the center of pressure (COP) value of the sitting position is analyzed using the four load cell data. To test the usability of the spinal health management system, the COP values of front, back, left and right torso tilts of healthy adults in a sitting position were measured with the posture balance device and 3D motion analysis program (Visual 3D, USA). After that, the COP values were compared and analyzed. As a result of the analysis, the COP direction data (front, back, left and right) measured with the posture balance device exactly matched the direction analyzed by the 3D motion analysis system.

The body-weight support (BWS) function, which helps to decrease load stresses on a user, is an effective tool for gait and balance rehabilitation training for elderly people with weakened lower-extremity muscular strength, hemiplegic patients, etc. This study conducts structural analysis to secure user safety in order to develop a rail-type gait and balance rehabilitation training system (RRTS). The RRTS comprises a rail, trolley, and brain-machine interface. The rail (platform) is connected to the ceiling structure, bearing the loads of the RRTS and of the user and allowing locomobility. The trolley consists of a smart drive unit (SDU) that assists the user with forward and backward mobility and a body-weight support (BWS) unit that helps the user to control his/her body-weight load, depending on the severity of his/her hemiplegia. The brain-machine interface estimates and measures on a real-time basis the body-weight (load) of the user and the intended direction of his/her movement. Considering the weight of the system and the user, the mechanical safety performance of the system frame under an applied 250-kg static load is verified through structural analysis using ABAQUS (6.14-3) software. The maximum stresses applied on the rail and trolley under the given gravity load of 250 kg, respectively, are 18.52 MPa and 48.44 MPa. The respective safety factors are computed to be 7.83 and 5.26, confirming the RRTS's mechanical safety. An RRTS with verified structural safety could be utilized for gait movement and balance rehabilitation and training for patients with hemiplegia.

Magnetic robots and their magnetic manipulation systems are innovative approaches for the diagnosis and therapy of minimally invasive medicine. Medical magnetic robots have been applied to targeted drug delivery, drilling in blood vessels, and a robotic capsule-endoscope for diagnosis and therapy [1–3]. Typically, the magnetic robots are controlled by various types of magnetic field: gradient, alternating, rotating, and uniform magnetic fields. The combination of Maxwell coil and Helmholtz coil are general configuration of magnetic manipulation system. However, the configuration is complicated and many power sources are required. To overcome these issues, we proposes a new method of hybrid control of magnetic fields for magnetic micro-robot manipulation based on three-axis Helmholtz coil. The hybrid control utilizes both gradient and uniform fields through switch control of the three-axis Helmholtz coil. For hybrid control, we utilizes 9 relay switches. Three switches separate the x, y and z coils. Six switches separate configuration of Helmholtz coil. In other words, three Helmholtz coils becomes six coils. When generating a rotating magnetic field, the six switches are turned on. When controlling the gradient field, the six switches are selectively turned off according to the moving direction. The hybrid control can provide precision control of micro/nano robot. In addition, the control method with system can be applied to micro/nano robot control without limitation to the robot mechanisms. To verify these advantages, we conducted various experimental tests.

This paper presents a new multifunctional active guidewire system for medical applications that uses a magnetic microrobot. The study demonstrated that the proposed microrobot system could swim and be controlled under Low-Reynolds-number (Re) environments in blood vessel models. The prototype of the robotic guidewire, which is driven within a three-axis Helmholtz coil system, consists of a guide-wire, spiral blade, drilling tip, and permanent magnet. The spiral-type microrobot showed stable active locomotion between magnetic field strengths 3 kA/m and 9.1 kA/m under driving frequency up to 70 Hz in a silicone oil (of viscosity 1000 est). The microrobot under a diameter of 1.5 mm produced a maximum moving velocity of 8.08 × 10−3 m/s at 70 Hz and 9.1 kA/m. In particular, the robotic guidewire produced 3D locomotion with drilling in the three-axis Helmholtz coil system. We verified active locomotion, towing of guidewire, steering, and drilling of the proposed robotic guidewire system through experimental analyses.

This paper discusses the development of a metal-hydride (MH) actuator, with excellent heat transfer performance, for application in a rehabilitative system incorporating an MH module. The operating mechanism of MH actuators requires that the mechanical power of the pneumatic actuator only be generated via heat transfer through a Peltier element and the absorption/desorption of a hydrogen-contained MH module. To achieve this aim, a 3D model was first designed for two MH modules, and a thermal analysis was carried out according to the type of contact with the Peltier elements to fabricate an MH module with improved heat transfer performance. LabVIEW software was used for automatic temperature control of the Peltier element in the MH actuator driving experiment. Zro.9TIo.iCro.6Fei.4, which yields a pressure-composition-temperature (PCT) curve of appropriate pressure and temperature ranges for a rehabilitative system, was selected as the hydrogen-absorbing alloy. In addition, the temperature conditions of the MH actuator driving experiment were restricted by two temperature control ranges (30–40 °C /30–50 °C) of the Peltier element. Within these Peltier element temperature ranges of 30–40 °C and 30–50 °C, results showed that the MH actuator was driven in the ranges of 2–3 atm and 2.5–3.5 atm, respectively. These findings indicate that the MH actuator proposed in this paper can be utilized to drive a rehabilitative system for elbow and knee joint exoskeletons.

This study investigated the feasibility of the Infrared (IR) sensor-based walking aids for detecting the gait intention. To compensate for the defects of Force Sensing Resistors (FSRs) or force sensors, such as the velocity control problem on gait slopes, we used IR sensors to investigate knee joint anterior displacement in order to recognize the gait intention. We also measure leg muscle activities and foot pressure, in order to verify our investigation. We placed two IR sensors on the rollator center to sense left and right leg walking intentions. We took EMG signals of four leg muscles, and analyzed them. Foot pressure analysis parameters were the measured force and mean pressure. We conducted experiments on twenty young healthy adults. The results show that knee joint anterior displacement increases according to gait slope and velocity. We confirm similar results of knee joint anterior displacement through the IR sensors.

This study shows the improvement of muscle activity and muscle strength imbalance in the lower extremities through independent exercise loads in vibration platform. Twenty females of age 20 participated in this study. The subjects were divided into WBV group, with more than 10% of muscle strength imbalance between left and right the lower extremities, and control group, with less than 10% of muscle strength imbalance between left and right the lower extremities. As the prior experiment showed, different exercise postures provide different muscular activities. As a result, the highest muscular activity was found to be in the low squat posture. Therefore, the LS posture was selected for the exercise in this experiment. Vibration intensities were applied to dominant muscle and non-dominant muscle, and the vibration frequency was fixed at 25Hz for the WBV group. The control group was asked to perform the same exercise as the WBV group, without stimulated vibration. This exercise was conducted for a total of 4 weeks. As a result, the WBV group which showed an average deviation of 16% before the experiment, tended to decrease approximately to 5%. In this study, vibration exercise using load deviation is shown to be effective in improving the muscle strength imbalance.

BACKGROUND Lower back pain has a lifetime prevalence of 80% for people in a modern society, and in recent years, spinal stabilization movement has been highlighted as a method to treat lower back pain and an unbalanced position. OBJECTIVE The objectives of this study were to assess the trunk muscle activities in accordance with the tilt angles (10∘, 20∘, 30∘, 40∘) during trunk tilt exercises with a 3D dynamic exercise device. METHODS Active tilt mode (a self-generated active movement in the angle and direction steered by the user) was used in this study. The rotation capability enabled the investigation of the anterior (A), anterior right (AR), right (R), posterior right (PR), posterior (P), posterior left (PL), left (L), and anterior left (AL) tilt directions. EMG signals of the trunk (3 global muscles: rectus abdominis, RA, external obliques, EO, latissimus dorsi, LD, and 1 local muscle: multifidus, MF) muscles were obtained. RESULTS The MF muscle activity was higher while the anterior tilt was maintained, and the abdominal muscle activity was higher while the posterior tilt was maintained. Also, as the tilt angle increased, the activity of the muscles opposite the tilt direction increased. CONCLUSIONS The results indicate that to maintain equilibrium through posture stabilization during whole body tilting, the human body maintains a proper interaction among the body segments as well as between the body and the execution environment. Moreover, stability is maintained through the co-contraction of antagonistic and agonistic muscles. In future studies, it will be important to conduct research on improving imbalance in the trunk muscles.

The objective of the study was to investigate the effect of 3-D stabilization exercise using a whole body tilt device. A musculoskeletal (MS) model of the whole body was developed, and used to calculate the forces in the spine, assisted by EMG measurement. The inverse dynamics was solved using the MS model of the whole body with the input data of the eight different directions of the tilt: anterior (A), posterior (P), anterior right (AR), posterior right (PR), anterior left (AL), posterior left (PL), right (R), and left (L), replicating the tilting directions of the whole body device. The anterior and posterior directions of tilt mainly induced superficial back and front muscle activations, respectively. However, deep muscles, such as the semispinalis and mulifidi, were activated in all directions of tilt. The joint resultant forces in the right and left direction of tilt were the least; but some higher activations and more diverse recruitments of muscles were demanded. In the present investigation, 3-D stabilization exercise can provide considerable muscle activation and exercise effect, with the minimum perturbation of structure. Therefore, the proposed direction of tilt can be used to strengthen the targeted muscles, depending on the patient’s muscle conditions.

The purpose of this study was to verify human physiological responses to emotional lighting system using LED (light emitting diode) flat lighting. Subjects were ten males in their twenties without medical history to eyes. Colors of LED lighting are red, orange, yellow, green, blue, purple and colorless (white). They were stimulated by LED lighting for 5 minutes. We measured body temperature, heart rate variability (HRV) and electroencephalogram (EEG) before and after color stimulus. In case of EEG analysis, relative power  wave ratio decreased in the groups of colorless, red and orange color light. Also, sympathetic nerve was more activated than parasympathetic nerve and the body temperature was increased in the groups of colorless, red, orange, yellow color light. On the other hand, relative power  wave ratio increased and parasympathetic nerve was more activated than sympathetic nerve and the body temperature was decreased in the groups of green, blue and purple color light. The results imply that the LED color lighting system in the realistic experiment environment. In the future, studies with compounded both colors and modes according to situation or auditory as nature sound or olfactory as aroma will be required.

Airborne hexavalent chromium (Cr(VI)) is a known pulmonary carcinogen and can be emitted from both natural and anthropogenic sources, including diesel emissions. However, there is limited knowledge about ambient Cr(VI) concentration levels and its particle size distribution. This pilot study characterized ambient Cr(VI) concentrations in the New Jersey Meadowlands (NJ ML) district, which is close to the heavily trafficked New Jersey Turnpike (NJTPK) as well as Chromium Ore Processing Residue (COPR) waste sites. Monitoring was simultaneously conducted at two sites, William site (∼50 m from NJTPK) and MERI site (∼700 m from NJTPK). The distance between the two sites is approximately 6.2 km. Ambient Cr(VI) concentrations and PM2.5 mass concentrations were concurrently measured at both sites during summer and winter. The summer concentrations (mean ± S.D. [median]), 0.13 ± 0.06 [0.12] ng/m3 at the MERI site and 0.08 ± 0.05 [0.07] ng/m3 at the William site, were all significantly higher than the winter concentrations, 0.02 ± 0.01 [0.02] ng/m3 and 0.03 ± 0.01 [0.03] ng/m3 at the MERI and William sites, respectively. The site difference (i.e., MERI > William) was observed for summer Cr(VI) concentrations; however, no differences for winter and pooled datasets. These results suggest higher Cr(VI) concentrations may be attributed from stronger atmospheric reactions such as photo-oxidation of Cr(III) to Cr(VI) in the summer. The Cr(VI) distribution as a function of particle size, ranging from 0.18 to 18 μm, was determined at the William site. It was found that Cr(VI) was enriched in the particles less than 2.5 μm in diameter (PM2.5). This finding suggested potential health concerns, because PM2.5 are easily inhaled and deposited in the alveoli. A multiple linear regression analysis confirmed ambient Cr(VI) concentrations were significantly affected by meteorological factors (i.e., temperature and humidity) and reactive gases/particles (i.e., O3, Fe and Mn).

Measurement of carcinogenic Cr(VI) in ambient PM is challenging due to potential errors associated with conversion between Cr (VI) (a carcinogen) and Cr(III) (an essential nutrient). Cr(III) conversion is a particular concern due to its80% atomic abundance in total Cr. US. Environmental Protection Agency (EPA) method 6800 that uses water-soluble isotope spikes can be used to correct the interconversion. However, whether the enriched Cr(III) isotope spikes can adequately mimic the Cr(III) species originally in ambient PM is unknown. This study examined the water solubility of Cr(III) in ambient PM and discussed its influence on Cr(VI) measurement. Ambient PM10 samples were collected on Teflon filters at four sites in New Jersey that may have different Cr emission sources. The samples were ultrasonically extracted with 5 mL DI-H2O (pH 5.7) at room temperature for 40 min, and then analyzed by ion chromatography-inductively coupled plasma mass spectrometry (IC-ICPMS). Cr(III) was below detection limit (0.06 ng/m3) for all samples, suggesting water-soluble Cr(III) species, such as CrCl3, Cr(NO3)3, and amorphous Cr(OH)3, in the ambient PM were negligible. Therefore, the enriched 50Cr(III) isotope spike (in the form of Cr(NO3)3) could not mimic the original ambient Cr(III). Only the conversion of 53Cr(VI) (in the form of K2CrO4) was taken into account when correcting the interconversion. We then used NaHCO3-pretreated MCE filters (prespiked with enriched isotope species) to measure Cr(VI) in the ambient PM10. The samples were ultrasonically extracted at 60 C pH 9 solutions for 40 min followed by IC-ICPMS analysis. Due to the correction of Cr(VI) reduction, the Cr(VI) concentrations determined by EPA method 6800, 0.26 ± 0.16 (summer) and 0.16 ± 0.11(winter) ng/m3 (n = 64), were significantly greater than those by the external standard curve, 0.21 ± 0.17 (summer) and 0.10 ± 0.07 (winter) ng/m3 (n = 56) (p0.01, Student's t-test). Our study revealed that appropriate application of EPA method 6800 is important because it only applies to soluble fraction of Cr species in ambient PM. Implications: Accurate measurement of carcinogenic Cr(VI) in ambient PM is challenging due to conversion between Cr(VI) (a human carcinogen) and Cr(III) (a human essential nutrient). The conversion of CR(III) is of particular concern due to its dominant presence in total Cr (80%). This study examined the water solubility of Cr(III) in ambient PM that was collected at four locations in New Jersey. Then we discussed the influence of Cr(III) solubility on the application of EPA method 6800, which utilizes enriched isotope spikes to correct the interconversion. Our results suggested that appropriate application of EPA method 6800 is important because it only applies to soluble fraction of Cr species.

This study intended to identify the effect of the long time whole body vibration exercise on the muscle function and postural balance. The twenties subjects in young people were recruited, and they were classified into WBV and Non-WBV groups. The vibration exercise was conducted 30 minutes a day for 4 days a week for a total 8 weeks, and the vibration protocol were 25Hz frequency and 5mm amplitude. To verify the muscle function according to the long time vibration exercise, the isokinetic muscle function of the knee joint torque was evaluated, while the total work of maximal peak torque to evaluate the enhancement effect of muscular strength, as well as the average power, angle to peak torque, and acceleration time to evaluate the muscular reaction, was analyzed. Also, changes in COP were measured and analyzed to research the functional change of the postural balance. As a result of the experiment, the Non-WBV group did not show changes in the muscular function and postural balance function, while the WBV group showed increased muscular function by 29.11%(maximal peak torque: 17.91%, total work: 26.78%, average power: 39.11%, angle to peak torque: 25.21%, acceleration time: 36.51%), and increased postural balance function by 64.76%.

This paper deals with the problem of accurately tracking a single target, which has various trajectories, moving through the environment of underwater wireless sensor networks (UWSNs). This paper addresses the issues of estimating the states of the target, improving energy efficiency by using a distributed architecture. Each underwater wireless sensor node composing the UWSNs is battery-powered, so the energy conservation problem is a critical issue. This paper provides algorithms increasing the energy efficiency of each sensor node by using the proposed Wake-Up/Sleep (WUS) scheme. An interacting multiple model (IMM) filter is applied to the proposed distributed architecture in order to cope with a target maneuver. Simulation results illustrate the performance of the proposed tracking filter according to the various target maneuver patterns.

In this study, a multidirectional posture and motion evaluation tool system using a camera-based vision system was developed. By installing a camera on the top, back, left, and front of the system, kinematical information of the participant was collected and analyzed on the sagittal, coronal, and transverse planes. A dedicated color light-emitting diode (LED) marker was developed for increasing recognition rate of marker. Based on LabVIEW, images collected from four cameras were printed on one screen, and the detection angle of each marker was calculated using the cosine second law. To evaluate the performance of this system, a motion analysis experiment was performed on 20 office workers in Jeonju area. The reliability was measured using POFOMO, Dartfish and the results were compared. The comparison results indicate that the concurrent validities of the two results for the knee angle, left shoulder, and right shoulder were highly correlated as [Formula: see text], 0.988, and 0.991, respectively. Because the POFOMO image analysis tool in the present system reduces the analysis time and involves a simpler measurement procedure than that of Dartfish, this system can be used as an effective device for measuring the posture alignment of the human body.

Electric wheelchairs developed so far have difficulties for elderly people to use, because of their bulkiness and heavy weight. To address this problem, this study presents a design for the construction of an electric wheelchair with an application of light duty materials at frame and a foldable structure that can be easily loaded in a narrow space. A structural analysis was performed to evaluate the structural safety of the foldable wheelchair. For the purpose of analysis, a carbon composite was used as the material for the frame; Structure Mechanics Module of COMSOL Multiphysics was used as the analysis software; and for the boundary condition, the lower part of the body frame was fixed, and a load of 150[Formula: see text]kg was applied to the upper part of the wheelchair. According to the results of the structural analysis, a maximum displacement of 2.869[Formula: see text]mm occurred at the handle where the carbon composite was applied, and tensile and compressive stress of 103[Formula: see text]MPa and 107.3[Formula: see text]MPa, respectively, were measured at the seat part of the wheelchair where the load was applied. The safety factors were 7.5 and 5.5 for tensile stress and compressive stress, respectively. A maximum variation of 0.0872[Formula: see text]mm occurred at the aluminum wheel shaft, and a maximum variation of 0.2046[Formula: see text]mm occurred at the joint. The maximum stress was 116.3[Formula: see text]MPa that corresponded to a safety factor of 2.66; this indicates that the wheelchair can be considered to be structurally safe as the safety factor exceeds the initial target of 2.