| The vibration of the machines, automobiles, and infrasound wave, etc. can lead to physiological function change and even pathological injury to human when it reaches some intensity. Some researches showed that the initial mechanism of the change and injury is related to biological resonance. Resonance with some energy can distort, translocate, and even destroy the organs. On the other hand, resonance stimulates the body receptors, through which the stimulation can be transmitted to the central nervous system, which induce some changes in the functions and form followed the influence on the molecular structure, biological oxidation and energy metabolism process of tissue, and in the end, the human lives would be endangered.The organs in thorax and abdomen such as heart, lung, stomach, liver, kidney, intestine and so on are very important to circulatory system, respiratory system, digestive system, urinary system, ect. The injuries of the organs in thorax and abdomen directly influence the vital signs and even life. Thus, it is necessary to know the resonance and its injury biomechanism of the organs in the thorax and abdomen. This is very important to research the prevention and treatment of organism resonance injury.Objective:Firstly to explore the resonance frequencies (RF) and vibration characteristics at low frequency of the organs of different kinds of animals in the thorax and abdomen, the factors affecting organs'RF, and if the difference exists between different kinds of animals. And then to observe the changes in the physiological function and the difference in the organs'injuries caused by resonance. Lastly to observe the mechanism of organs'injury caused by resonance. These should be the base of the prevention, diagnosis and treatment research of organ resonance injury in the thorax and abdomen.Method:1. To measure the RF and vibration characteristics at low frequency of the organs of the rat and the rabbit in the thorax and abdomen The acceleration sensors were pasted on the surface of the organs after the animals had been anaesthetized. The RF and spectral responses of the rat organs from back to chest were measured by hammering method (HMM), and the RF and amplitude-frequency characteristics of the rabbit organs and rat liver from back to chest were measured by sine sweeping-frequency vibration method (SSVM).2. To observe the changes in the physiological function and organs injuries of rat and rabbit caused by resonanceThe animals were vibrated continuously at two frequencies near the RF and one frequency far away from the RF of organs in the thorax and abdomen. The changes in the physiological function at prescribed time were compared among these frequencies. After six hours'vibration, the animals were anatomized to observe the injury and the specimens were taken for optical observation.3. To discuss the mechanism of organ resonance injuryThe strength caused by crash or pulling between organs was analyzed by measuring amplitude and phase difference between organs. And the biomechanism of organs resonance injuries was analyzed by computer emulation through establishing the finite elements (FE) based on the organs material characteristic and crash.Results and Conclusions:1. The RF of rat stomach, kidney, heart, intestine, lung and liver are separately at 7.0Hz, 6.6Hz, 4.8Hz, 3.6Hz, 3.2Hz and 3.0Hz. The RF of rabbit stomach, kidney, heart, intestine, lung and liver are separately at 8.0Hz, 7.0Hz, 6.0Hz, 6.0Hz, 5.0Hz and 7.0Hz. The organs have high amplitudes near their RF, and the organs may be injured or functionally injured when they are vibrated near or equal to their RF. The RF and MAMP of rat and rabbit organs in the thorax and abdomen are not statistically related to body weight, organs mass or organs volume. The same organs of different kinds of animals have different RF. The organs RF and amplitude can be altered by changing their restriction conditions or material mechanics characteristics. When the organs in the thorax and abdomen resonate, the organs with light density have higher amplitude than those with heavy density.2. The blood pressure, pulse and breath of rat and rabbit ascended rapidly when the resonance lasted 1 minute. And all of these physiologic indexes reached maxima in 1 to 3 minutes and then descended gradually. These physiologic indexes were lower than normal values after the resonance lasted 30 minutes. Resonance can reduce the body temperature conditioning ability of rat and rabbit. Among the organs in the thorax and abdomen of the rat and the rabbit, the lung was the main target organ injured by resonance.3. When the rabbits were vibrated by sine wave at 5Hz from back to chest the phase difference between heart and lung was significantly larger than that between stomach and intestine, between liver and intestine, or between kidney and intestine. The larger the phase difference between organs in resonance, the higher the speed and energy of organs crashing or pulling, and the more the organs injury. The organs with non-homogeneous material can be injured more easily in resonance than that with homogeneous material. The organs being crashed in resonance can be injured more easily than that being simply vibrated. So, one of the biomechanism of lung resonance injury is related to crash between organs caused by lung's large amplitude and large phase difference between heart and lung, and is related to non-homogeneous material characteristic of lung which may make inner capillary vessel destroy easily.In conclusion, the resonance of organs in the thorax and abdomen will cause the changes in the physiological function of animal, and even the injuries of organs. One of the biomechanism of injury is related to the crash among organs caused by their large amplitudes and large phase difference between organs, and is also related to material characteristic of organs. |
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