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Monitoring core body temperature (CBT) allows observation of heat stress and thermal comfort in various environments. By introducing a Peltier element, we improved the zero-heat-flux core body thermometer for hot environments. In this study, we performed a theoretical analysis, designed a prototype probe, and evaluated its performance through simulator experiments with human subjects. The finite element analysis shows that our design can reduce the influence of external temperature variations by as much as 1%. In the simulator experiment, the prototype probe could measure deep temperatures within an error of less than 0.1 °C, regardless of outside temperature change. In the ergometer experiment with four subjects, the average difference between the prototype probe and a commercial zero-heat-flux probe was +0.1 °C, with a 95% LOA of −0.23 °C to +0.21 °C. In the dome sauna test, the results measured in six of the seven subjects exhibited the same trend as the reference temperature. These results show that the newly developed probe with the Peltier module can measure CBT accurately, even when the ambient temperature is higher than CBT up to 42 °C.

Laparoscopic surgery is a representative operative method of minimally invasive surgery. However, most laparoscopic hand instruments consist of rigid and straight structures, which have serious limitations such as interference by the instruments and limited field of view of the endoscope. To improve the flexibility and dexterity of these instruments, we propose a new concept of a multijoint manipulator using a variable stiffness mechanism. The manipulator uses a magneto-rheological compound (MRC) whose rheological properties can be tuned by an external magnetic field. In this study, we changed the shape of the electromagnet and MRC to improve the performance of the variable stiffness joint we previously fabricated; further, we fabricated a prototype and performed basic evaluation of the joint using this prototype. The MRC was fabricated by mixing carbonyl iron particles and glycerol. The prototype single joint was assembled by combining MRC and electromagnets. The configuration of the joint indicates that it has a closed magnetic circuit. To examine the basic properties of the joint, we conducted preliminary experiments such as elastic modulus measurement and rigidity evaluation. We confirmed that the elastic modulus increased when a magnetic field was applied. The rigidity of the joint was also verified under bending conditions. Our results confirmed that the stiffness of the new joint changed significantly compared with the old joint depending on the presence or absence of a magnetic field, and the performance of the new joint also improved.

Hip protectors can reduce the incidence of hip fractures. However, low user acceptance and compliance in use remain a major obstacle in the effective use of hip protectors, due to its discomfort and extra effort needed to wear it, etc. A leak-allowed air cushion is an air-bubble cushion designed to have one or some orifices on the side. In this cushion, an impact load is shunted to open air with airflow through orifice(s), and the energy is dissipated by the friction of the airflow. With the lightness, the flexibility, and the inexpensiveness, this cushion has a potential to be accepted by the target users at high levels of compliance. The purpose of this study was to evaluate a potential of the cushion as a hip-protector material by comparing with other three commercially-variable impact attenuation materials: polyethylene elastmer; silicon gel; and porous polyurethane. To this end, we performed impact tests for pads made of the materials using a falling-mass impact loader. The pad made of leak-allowed air cushions reduced the peak impact force from 7700N (recorded with no pad) to 1213 N, which was 38—64 % lower than the attenuated peak forces recorded in the other material pads. We concluded that the leak-allowed air cushion could be a novel hip protector material with high capacity of impact-force attenuation.

Investigating sweat component concentrations is important for managing electrolyte balance and water content in the body, monitoring hydration and heat stress, and preventing dehydration. Predicting rehydration timing for regulating body temperature and preventing dehydration is particularly challenging because it depends on the individual's health and exercise status, which affects the amount and composition of sweat. Consequently, there is a demand for a simple analytical method using a portable device for practical applications. In this study, sodium and potassium concentrations were evaluated in aqueous solutions using multi-wavelength NIR spectroscopy. The number of wavelengths necessary for accurate analysis was also verified using multiple regression analysis. The concentrations of aqueous sodium and potassium electrolytes were evaluated by multiple regression analysis using the differential absorbance of the samples obtained using a NIR spectrometer. By using four and five wavelengths for each of the two electrolytes, the accuracy of the correlation coefficient between the optically evaluated concentration and the concentration measured using a commercial ion meter exceeded 0.9995. A multi-wavelength NIR spectroscopic method was developed for the optical evaluation of electrolyte concentrations in aqueous solution. The concentration evaluation was achieved using two wavelengths, leading to the development of a simple device for measuring sweat components. [ABSTRACT FROM AUTHOR]