MinebeaMitsumi (Japan)

Available evidence on favorable nutritional factors for preventing osteoporosis remains controversial. Considering the recent increases in life expectancy, we investigated the relationship between incident osteoporotic fractures and dietary habits in early and late postmenopausal phase women. Subjects were Japanese postmenopausal outpatients recruited at a primary care institution in Nagano Prefecture (Nagano Cohort Study). Patients with critical or acute illness or secondary osteoporosis were not included in this study. In total, 1,071 participants were prospectively followed for a mean of 5.8years. The cohort was divided into early (≤ 70years) and late (> 70years) postmenopausal phases based on median age. Dietary nutrient intake was estimated by the food frequency questionnaire method. According to baseline nutrient intake characteristics, we focused on protein/energy and Ca/NaCl intake ratios, which were also divided by the median values. Kaplan-Meier plots revealed a significantly higher occurrence of fractures for the high protein/energy intake group in early postmenopausal subjects (P = 0.009), whereas the low Ca/NaCl intake group in late postmenopausal subjects exhibited a significantly earlier occurrence of fractures (P = 0.002). Multivariate Cox regression uncovered significant independent risks of higher protein/energy (HR 1.35; 95% CI 1.04-1.74) and lower Ca/NaCl (HR 0.79; 95% CI 0.63-0.99) intake ratios for incident osteoporotic fractures in the early and late postmenopausal cohorts, respectively. Distinct dietary risk factors for osteoporotic fractures were identified in early and late postmenopausal phase women. Appropriate nutritional guidance according to patient age will be important for maintaining bone health and quality of life.

Shortage of labor and increased work of young people are causing problems in terms of care and welfare of a growing proportion of elderly people. This is a looming social problem because people of advanced ages are increasing. Necessary in the fields of care and welfare, pneumatic artificial muscles in actuators of robots are being examined. Pneumatic artificial muscles have a high output per unit of weight, and they are soft, similarly to human muscles. However, in previous research of robots using pneumatic artificial muscles, rigid sensors were often installed at joints and other locations due to the robots’ structures. Therefore, we developed a smart actuator that integrates a bending sensor that functions as a human muscle spindle; it can be externally attached to the pneumatic artificial muscle. This paper reports a smart artificial muscle actuator that can sense contraction, which can be applied to developed self-monitoring and robot posture control.

A feasibility study on applying a 24-GHz massive phased array to an on-vehicle wireless power transfer system is described for remote structural health monitoring in tunnels. Array directional patterns are generated to evaluate the amount of accumulated received energy when the beam direction is controlled within a narrow angle range to prevent the spreads of reflected waves. From the viewpoint of frequency sharing with existing wireless systems, we evaluated the radio field strengths inside and outside a tunnel model when a radio wave absorber was used around a receive antenna through ray-tracing simulations. Simulation results demonstrated that the radio field strength at inter-vehicle distances were far below an allowable in-band spurious level.

Pentosidine (PEN) and carboxymethyl-lysine (CML) are well-recognized advanced glycation end products (AGEs). However, how these AGEs affect the pathophysiology of osteoporosis and osteoporotic fractures remains controversial. This cross-sectional study aimed to investigate the associations of PEN and CML with bone markers, bone mineral density (BMD), and osteoporotic fractures in postmenopausal women from the Nagano Cohort Study. A total of 444 Japanese postmenopausal outpatients (mean ± standard deviation age: 69.8 ± 10.2 years) were enrolled after the exclusion of patients with acute or severe illness or secondary osteoporosis. The relationships among urinary PEN and serum CML levels, various bone markers, lumbar and hip BMD, and prevalent vertebral and long-bone fractures were evaluated. PEN associated significantly with prevalent vertebral fracture after adjustment for other confounders (odds ratio [OR] 1.59, 95% confidence interval [CI] 1.22–2.07; P < 0.001), but not with lumbar BMD. In contrast, a significant negative correlation was found between CML and lumbar BMD (r = − 0.180; P < 0.001), and this relationship was significant after adjustment for confounders (OR 0.84, 95% CI 0.76–0.93; P < 0.01). Although patients with prevalent vertebral fracture had significantly higher CML levels, the association between CML and prevalent vertebral fracture did not reach significance in the multivariate regression model. Both PEN and CML may play important roles in bone health for postmenopausal women, possibly via different mechanisms.

A highly efficient CMOS rectifier for RF energy harvesting has been developed (using 0.18-µm CMOS technology). To operate with high efficiency even under extremely low input power conditions, the voltage-doubler-based rectifier was implemented using an effective combination of self-Vth-cancellation (SVC) and photovoltaic (PV)-assisted techniques. In this rectifier, the threshold voltage (Vth) of the diode-connected MOSFET was compensated for by a DC bias voltage generated from not only the on-chip PV cells, but also from the output voltage of the rectifier itself. Therefore, the rectifier operated with high efficiency even under low input power conditions. Furthermore, a bias voltage limiter using simple pn diodes was adopted to regulate the excessive Vth compensation effectively and realize a high efficiency in the operation of the rectifier over a wide power range. The radio frequency to DC power conversion efficiency (PCE) of 30.8% was achieved at an input power level of -15 dBm, a frequency of 1 GHz, an output load resistance of 10 kΩ, and a light irradiance of 10 mW/m2.

Although associations among obesity, adipocytokines, and bone mineral density have been reported, the influence of adipocytokines on osteoporotic fractures remains unclear. This study aimed to assess the impact of the adipocytokines leptin and adiponectin on the risk of incident vertebral and long-bone fractures in postmenopausal women. Clinical data were obtained from the retrospective Nagano Cohort Study of outpatients followed at a single primary care institute in Nagano Prefecture, Japan, between 1993 and 2018. The primary outcome was the occurrence of incident vertebral or long-bone fractures. In total, 1167 Japanese postmenopausal women (mean age: 65.9years) completed the follow-up and the average observation period was 7.2years. The subjects were divided into 4 groups (quartile 1 to 4) based respective leptin and adiponectin values. Kaplan-Meier analysis demonstrated a significantly lower incident long-bone fracture rate in the higher quartiles of serum leptin levels (p=0.002). A significantly higher and more rapid occurrence of incident vertebral fractures, but not long-bone fractures, was found in the highest adiponectin quartile (p<0.001). A Cox proportional hazards model adjusted for confounders including age, body weight, and either leptin or adiponectin revealed lower leptin levels and higher adiponectin levels as significant independent risk factors for incident long-bone fractures (hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.50-0.96; p=0.03) and vertebral fractures (HR 1.18, 95% CI 1.02-1.37; p=0.02), respectively. Therefore, serum leptin and adiponectin may be independent risk factors for osteoporotic fractures affecting different bone types and sites. Determining patient adipocytokine levels may help predict the occurrence of specific osteoporotic fractures, thereby enabling optimal treatment for osteoporosis and improving quality of life.

Bayesian optimization is applied to antenna subset selection and transmit phase adjustment in distributed microwave power transfer. Both of the optimization controls are iteratively carried out based on energy feedback to maximize the received power in the low-complexity hardware configuration of massive antenna deployment. In addition, the computational complexity is reduced by exploiting the cyclic property of received power with respect to the transmit phase rotation. Our simulation results demonstrate that 95 percent of the maximum achievable received signal power was attained in 97 percent of the total trials by using 34 samples in both controls.

Maintenance of infrastructures, e.g. road, tunnel, bridge, etc., is one of most important issues that must be solved for sustainable society. It is usually measured and checked by human, however, it is very hard to measure a lot of infrastructures. Recently, new sensors to measure the infrastructures are developed and it is easy and convenient for the maintenance of the infrastructures. It is requested to expand a life time of the sensors. So battery-less sensor is hopeful expected because life time is decided by battery time.

Purpose of this study is to clarify iron loss distribution on laminated stator core by an interlocking by means of a heat-measurement method with a thermography camera. This method has been applied to the surface mounted permanent magnet (PM) motors, which are removed stator windings, to measure temperature distributions on the stator surface during the PM rotor is rotating. Because the stator cores have no the interlocking, the previous study could not evaluate the influences of interlocking on the iron loss distribution of the stator core. The core loss of the stator core increases due to the interlocking laminations. To design a stator core having low iron loss for a high efficiency motor, the causes of increasing core losses including the interlocking lamination should be analyzed in detail. In this paper, how to evaluate iron loss distribution on stator core by interlocking by means of a heat-measurement method and the evaluated results are reported.