Osteoporosis can be associated with the disordered balance between osteogenesis and adipogenesis of bone marrow-derived mesenchymal stem cells (BM-MSCs). Although low-frequency mechanical vibration has been demonstrated to promote osteogenesis, little is known about the influence of acoustic-frequency vibratory stimulation (AFVS). BM-MSCs were subjected to AFVS at frequencies of 0, 30, 400, and...

It is commonly believed that the exceptional sensitivity of mammalian hearing depends on outer hair cells which generate forces for amplifying sound-induced basilar membrane vibrations, yet how cellular forces amplify vibrations is poorly understood. In this study, by measuring subnanometer vibrations directly from the reticular lamina at the apical ends of outer hair cells and from the basilar...

Equipment-induced vibration is widely recognized as a health hazard. It is a physical stressor to which many people are exposed at workplace. Mining industry is no exception. In spite of extensive research undertaken in the developed countries, information on the magnitude of the problem in India is not available. An estimated 1 million workers were engaged in the Indian mining industry in the ...

It has been suggested that a suppression of maximal voluntary contraction (MVC) induced by prolonged vibration is due to an attenuation of Ia afferent activity. The purpose of the present study was to test the hypothesis that aftereffects following prolonged vibration on muscle activity during MVC differ among plantar flexor synergists owing to a supposed difference in muscle fiber composition....

If future electric and hybrid electric vehicle batteries are to be designed such that the impact of vibration induced resonance is minimized, engineers tasked with the design of the vehicle's energy storage system must have a rigorous understanding of key system attributes such as the natural frequencies of the cell, the level of damping present and the mode shapes induced within the battery un...

The objective of this paper is to identify the dynamic source time function for the train-induced vibration of underground tunnels. Under the consideration of the gaps between adjacent slabs and the constraint from equal-spacing fasteners, the vertical force loaded by the moving train is modelled by a periodical source time function. Consequently, the induced vibration at any specified observat...

The transitory effects of hand vibration (ah, w = 3.16 m/s2 during three minutes) on postural vasomotor functions of skin capillary blood flow rate in the finger were studied by the local 133xenon washout technique in ten men with vibration induced white finger (VWF), nine men professionally exposed to hand-arm vibration but without finger symptoms (HAV), and eight male controls (MC). The follo...

1. The parameters of presynaptic inhibition of the Ia spindle afferents from soleus muscle by vibration have been investigated. The inhibitory effects increase with the amplitude of vibration, but decrease when the vibration frequency is increased.2. The monosynaptic reflex threshold of twenty-one single soleus motor units activated in the H (Hoffmann) reflex by a single electrical stimulus to ...

This study was conducted to clarify the effects of vibration on the peripheral nerves. Rat tails were exposed to vibration (acceleration 56.9 m/s2, frequency 60 Hz, amplitude 0.4 mm for two or four hours daily, six days a week. The maximum motor conduction velocity (MCV), the amplitude of evoked response, and the motor distal latency were measured on rat tail nerves every two months. Thin secti...

OBJECTIVES To compare the noise and vibration levels associated with three hand-held rock drills (pneumatic, hydraulic and electric) currently used in South African mines, and a prototype acoustically shielded self-propelled rock drill. METHODS Equivalent A-weighted sound pressure levels were recorded on a geometrical grid, using Rion NL-11 and NL-14 sound level meters. Vibration measurements...