Recent evidence has been presented demonstrating that group III mechanoreceptors comprise an important part of the sensory arm of the exercise pressor reflex, which in turn functions to increase arterial blood flow to contracting skeletal muscles. Although group III afferents are stimulated by mechanical distortion of their receptive fields, they are also stimulated by bradykinin, which is produced by skeletal muscle when it contracts. Moreover, blockade of B (bradykinin)₂ receptors has been shown to decrease the magnitude of the exercise pressor reflex. Nevertheless, the effect of blockade of B₂ receptors on responses of group III afferents to contraction is not known. We therefore determined the effect of B₂ receptor blockade with HOE 140 (40 μg/kg) on the responses to both static and intermittent contraction of group III afferents with endings in the triceps surae muscle of decerebrated unanesthetized cats. We found that HOE 140 significantly attenuated (P = 0.04) the responses of 14 group III afferents to static contraction, but did not significantly attenuate (P = 0.16) the responses of 16 group III afferents to intermittent contraction. The attenuation induced by HOE 140 was present throughout the static contraction period, and led us to speculate that blockade of B₂ receptors on the endings of group III afferents decreased their sensitivity to mechanical events occurring in the working muscles.

In this paper, the impression of various kinds of auditory signals currently used in automobiles and a comprehensive evaluation were measured by a semantic defferential method. The desirable acoustic characteristic was examined for each type of auditory signal. Sharp sounds with dominant high-frequency components were not suitable for auditory signals in automobiles. This trend is expedient for the aged whose auditory sensitivity in the high frequency region is lower. When intermittent sounds were used, a longer OFF time was suitable. Generally, “dull (not sharp)” and “calm” sounds were appropriate for auditory signals. Furthermore, the comparison between the frequency spectrum of interior noise in automibiles and that of suitable sounds for various auditory signals indicates that the suitable sounds are not easily masked. The suitable auditory signals for various purposes is a good solution from the viewpoint of universal design.

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In electric-powered cars, the production of which is increasing, the HVAC system is responsible for most of the noise inside the car’s cabin, causing significant discomfort for passengers. Moreover, the noise produced by the HVAC affects the perceptible sound inside the car cabin, significantly impacting the perceived quality of the vehicle. It is thus essential to investigate and quantify people’s preferences concerning HVAC noise. Our previous research revealed differences in the HVAC noise between hybrid electric (HEV) and internal combustion engine (ICEV) vehicles. A subsequent factor analysis revealed that the adjectives used to describe the sounds can be grouped into two main dimensions: Aesthetic and Loudness. The present paper highlights the results of a listening test that aimed to identify possible differences in the perception of HVACs’ sound quality between Italian and Japanese subject groups, for ICEV and HEV, in different functioning conditions. Results revealed that the most remarkable difference emerges at high air flow rates, where the Japanese group perceived the quality of sound and annoyance, respectively, to be significantly lower and significantly higher than the Italian group.

Car horns were originally installed in vehicles for safety. However, many urban areas in several countries face noise problems related to the use of car and motorbike horns. To propose measures to suppress the use of horns, relationships between horn use and factors including driver awareness and behavior, traffic environment, and the transportation system should be investigated. The present study therefore conducted surveys to grasp the current circumstances of horn use and traffic at urban intersections in Taiwan. The relationship between horn use and the traffic volume of standard-sized vehicles was found. According to an analysis of horn use during traffic signal cycles, in many cases, horns were honked after entering intersections to turn left. In particular, horns were honked when the driver waited more than 4 s for the car in front to start moving after the green light allowing left turns was turned on. An analysis of noise levels at intersections showed that the maximum noise level value (L_Amax) could be reduced if vehicle horns were not used. Multiple regression analysis also indicated that L_Amax values increased with the frequency of horn use. The equivalent continuous A-weighted sound pressure level (L_Aeq,10min) did not change with driver horn use, and increased with the traffic volume of motorcycles.