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PubMed1992

The effectiveness of grip bands in reducing racquet vibration transfer and slipping.

The effectiveness of cushion grip bands in reducing impact shock and vibration transfer, and slipping in tennis racquets has been investigated. The results also apply, in principle, to badminton and squash racquets, and to golf clubs. An artificial arm (manusimulator) replicating the structure and all the important properties of the real human arm (shoulder, upper- and forearm, hand, soft tissue- and muscle simulators, etc.) was used together with a standard tennis racquet for the investigation. Laser beams were employed for precision adjustment of the spatial racquet position and the ball impact location. The impact velocity was standardized at 20 m.s-1 +/- 1.2%, while the impact point was located 32.5 +/- 2 mm distal to the sweet spot (the nodal point of the fundamental transverse vibration mode) on the racquet long axis. The grip circumference for the 26 different grip bands tested was controlled at 116 +/- 1 mm (grip size 5), and the adjustable manusimulator grip pressure was kept at preset values. Impact shock and post-impact racquet vibrations were determined by manusimulator-accelerometry, while slipping resistance was measured by friction methods. The major finding was that cushion grip bands do statistically significant (at P = 0.05) reduce impact shock and vibration transfer in tennis racquets, albeit to varying degrees depending on the brand. At present, there is no clear indication whether these reductions are, in fact, biologically relevant. Very large differences were found to exist between the various grip band types as regards the reduction of slipping.

Humans↗
PubMed2004

Effect of ultrasonic vibration on the retention of adhesively luted intra-radicular posts.

The aim of this study was to determine the effect of prolonged ultrasonic vibration on tensile force necessary to dislodge two different post types luted with an adhesive resin. Extracted human canine teeth were decoronated and root-filled. Either a ceramic or stainless steel intra-radicular post was luted into each root with resin-based cement. Half the samples in each group were randomly assigned to be subjected to ultrasonic vibration of the post (test group), the remaining samples did not receive vibration (control group). The tensile force required to dislodge each post was then determined in a universal testing machine. The mean force required to dislodge the stainless steel posts in the control group was 510.1N (SD 170.6) and in the 'treatment' group it was 539.5N (SD 163.3). For the ceramic posts in the control group the mean force was 447.8N (SD 165.5) and in the 'treatment' group it was 473.9N (SD 137.8). There was no statistical difference between the groups (p = 0.597). Within the limitations of this in-vitro study, the results cast doubt on the ability of application of ultrasonic vibration to displace/loosen intra-radicular posts luted with a resin-based cement.

Cementation↗
PubMed2004

Vibration anesthesia: a noninvasive method of reducing discomfort prior to dermatologic procedures.

In some dermatologic and cosmetic procedures, local anesthesia is not sufficient for relieving pain; often patients are averse to injections. We propose vibration anesthesia, the use of vibration delivered with commercially available inexpensive massagers to reduce discomfort. We find the analgesic effect of vibration helpful in minimizing pain in patients undergoing injections of botulinum toxin type A treatment for hyperhidrosis, injection of filler substances such as Restylane and Juvederm, laser therapy for leg veins, nail-fold injections, Q-switched laser treatment of tattoos, incision and drainage of abscesses, and cautery of facial warts, as well as facilitating anesthetic injections for needle-phobic patients. We expect that additional uses will be found as experience with this modality grows. Although the use of vibration anesthesia generally does not eliminate pain completely, it can serve to make the injection or procedure much more tolerable.

Anesthesia↗
PubMed2005

[Modeling vocal-fold vibration via integrating two-mass model with finite-element method].

Modeling vocal-fold vibration is extremely significant in realizing the vibration properties of human vocal folds and investigating their physiological and pathological characteristics. A combined model presented is two mass-finite element (T-F) model, which integrates all merits of both the finite element method (FEM) model and the asymmetric two-mass model of vocal folds. The high-speed glottis graph (HGG) can also be synthesized by the model. The result shows that T-F model can simulate the vibration behavior of normal and pathological vocal folds in a more realistic way with competitively computational speed. Therefore, the T-F model is helpful to gaining a thorough understanding of the vibration properties of vocal folds.

Computer Simulation↗
PubMed2001

Vibrations in milk transportation.

During transport of milk in three-cell tank truck, the vibrating acceleration ranged generally on the level of 0.5 to 2g (0.5 to 20 m/s2) at the vibrating frequency 2 to 60 Hz. The vibration increased proportionally to the driving speed of tank truck, being dependent on the type and surface condition of road and the efficiency of space filling in the container, with lower vibration levels at lower filling.

Animals↗
PubMed1992

Laryngeal paralyses: theoretical considerations and effects on laryngeal vibration.

The neurological causes of vocal fold paralyses have been well documented. However, the effect of these disorders on laryngeal vibration is not well understood. A theoretical four-mass model of the larynx, based on the work of Ishizaka and Isshiki (1976) and Koizumi, Taniguchi, and Hiromitsu (1987), was developed and adapted to simulate laryngeal biomechanical behavior. The model was used to evaluate various states of asymmetric laryngeal vibration. Input parameters that relate observed laryngeal function and model simulation were developed. Laryngeal paralyses were simulated by their predicted effect on these parameters. Simulations were compared with available data on glottal vibration in laryngeal paralyses. Complex modes of vibration were seen with certain combinations of asymmetrical lower mass stiffness and initial glottal gap.

Computer Simulation↗
PubMed2005

[Effects of 100 Hz vibration on ultrastructure of soleus muscle in tail-suspended rats].

OBJECTIVE: To study the effects of 100 Hz vibration on ultrastructure of intrafusal and extrafusal fibers in soleus muscle of tail-suspended rats. METHOD: Weightlessness was simulated by tail suspension of female rats. The ultrastructure of intrafusal and extrafusal fibers of soleus muscle were examined after exposure to 100 Hz vibration. RESULT: The ultrastructure of intrafusal and extrafusal fibers of soleus muscles showed obvious retrograde changes after 7 d tail suspension, whereas these changes were not obvious after 7 d tail suspension plus 100 Hz vibration. CONCLUSION: High frequency vibration can counteract the effect of simulated weightlessness on ultrastructure of intrafusal and extrafusal fibers in soleus muscles of rats.

Animals↗
PubMed2005

[A vasoregulating function of the major vessels of the upper limbs in patients with vibration disease].

AIM: To investigate a vasoregulating function of the endothelium of the upper limbs' major arteries in patients with vibration disease (VD); to determine VD role in pathogenesis of vascular disorders. MATERIAL AND METHODS: A total of 54 VD men free of cardiovascular disease (age 42.4 +/- 0.98 years) with mean occupational local vibration contact 19.4 +/- 1.12 years entered the study. Diameter of the brachial and radial arteries and hemodynamics in them were measured with triplex scanning of the vessels. Hemodynamics in smaller vessels was examined with dopplerography. A vasoregulating function of vascular endothelium was assessed with a postocclusion test with reactive hyperemia, cold and nitroglycerin tests on sites distant from the sites exposed to vibration and close to such sites. RESULTS: Abnormal endothelium-dependent responses at distal parts of the radial artery as marked vasoconstriction in the phase of ischemia and in response to cold, inhibition of systolic and volume speed of blood flow in reactive hyperemia were found. The strongest changes were seen in finger hand arteries. No disturbances of endothelium-independent reactions in nitroglycerin test were seen. CONCLUSION: Vascular disturbances in the action of local vibration on the workers' hands are explained not only by systemic impacts but also by local disorders of endothelial function of hand vessels.

Adult↗
PubMed2005

[Morpho-functional characteristic of kidneys in mother, fetus and the offspring subjected to vibration of industrial frequency during gestation].

The aims of the present study were to investigate the nature of morpho-functional changes in the kidneys in mother, fetus and the offspring subjected to the dosed effect of vibration during gestation. The study was performed in pregnant female Wistar rats (n = 28), fetuses (n = 26) and the offspring aged 3 months (n = 20). Rats were subjected to vibration from Day 9 to Day 19 of gestation (the period of intensive metanephros development), using vibration test bench with fixed parameters: frequency of 32 Hz and acceleration of 50 m/s2. Renal structures were studied using morphometric methods, the ultrastructure of renal cells was examined. In pregnant females and in mature offspring, the nephrons of subcapsular, inrtacortical and juxtamedullary zones were studied. Taking into account organo- and histogenesis of embryonic kidney, in fetuses only nephrons of the last three stages of differentiation and S-shaped tubules were studied. It was found that in adult animals juxtamedullary and subcapsular renal zones were most sensitive to the effect of vibration. Morpho-functional signs of the damage to the filtration barrier were also noted. In the metanephros of fetuses, the maturation of nephrons was retarded, and the regular formation of intercellular junctions was disturbed. In the kidneys of immature offspring the number of nephrons was increased.

Animals↗
PubMed2005

[Right ventricular function and pulmonary circulation hemodynamics in patients with vibration disease].

AIM: To study contractile and diastolic function of the right ventricle, mechanic activity of the right heart, hemodynamics of the pulmonary circulation in patients with vibration disease (VD). MATERIAL AND METHODS: The study group consisted of patients in contact with vibration (15 subjects without VD symptoms, 44 patients with VD of the first degree and 10 patients with VD of the second degree). 20 control males had no contact with vibration. RESULTS: VD patients developed right ventricular (RIO dysfunction: disturbed diastolic function, hypodynamic syndrome of the first degree accompanied with reduced ejection fraction, stroke output and cardiac index. In VD, RV dysfunction appears in parallel with left ventricular dysfunction due to high pressure in pulmonary circulation and interventricular interaction. CONCLUSION: VD-specific features of the lesser circulation and RV function give rise to formation of heart failure. Thus, early diagnostic and prophylactic measures should be taken in subjects in contact with vibration.

Disease Progression↗
PubMed2006

Resonance of sputum spigot with air vibration.

A mathematical model calculation has been presented on the resonant frequency of the oscillating sputum spigot in a cylindrical pipe, with which we investigated similar phenomena in bronchial tubes. We confirmed the theoretical results by two types of experiments using pseudo-sputum (5 and 10% solutions of mucin) spigots instead of a human pulmonary one, and found the model was suitable for estimating the effects of clinical vibrational treatments expectorating sputum spigots plugged in small bronchi. The main points of the paper are summarized as follows. 1. The validity of the fluid model used was verified using reported experimental data of Litt and co-workers. After adjusting their data in a Casson plot, Casson fluidity was found to be the best parameter to represent viscosity of the sputum. 2. A theoretical investigation on the vibrational sputum spigots in narrow tubes was done using an analytical model calculation. From the resultant formula, which expresses the resonant frequency of the oscillation of the spigot with its physical values (the radius of the airway, the length of the spigot, the elasticity of the sputum, and the surface tension), many points became clear; for example, the resonant frequency of sputum spigot vibration in a narrow bronchial tube is too high to propagate there under the effective influence of surface tension. 3. Two experiments were performed with pseudo-sputum (5 and 10% solutions of mucin) instead of a human pulmonary one. After substituting the resonant frequencies of the pseudo-sputum spigot vibration in our tube experiment into the resultant formula derived from our analytical model calculation we estimated the elasticity values, which agreed with those from our plate experiment. The validity of our theory was strongly supported by this agreement.

Elasticity↗
PubMed1991

Whole-body vibration exposure in subway cars and review of adverse health effects.

New York City Transit Authority subway operators have a high prevalence of back problems. To evaluate a possible dose-response relationship for whole-body vibration, we studied subway car vibrations measured and analyzed according to the International Standard Organization 2631 and Verein Deutscher Ingenieure 2057 standards. Vibration transducers in triaxial orientation were mounted in a disc pad directly on the subway operator's seat. The relatively high lateral and vertical accelerations, primarily the combined effects, may all contribute to the high rate of musculoskeletal complaints, especially of the lower back. Other factors aggravating whole-body vibrations include primitive ergonomic cab and seat design, forced body posture, high noise levels, and organizational work stress.

Back Pain↗
PubMed1991

[Physiological and hygienic evaluation of combined effects of vibration, noise and dynamic physical load in tea plant-picking machine operators].

The article deals with complex influences of local vibration, noise and physical overload in ACHR-330 tea-plucking machine operators. 3 sets of experiments included measurements of the vibration and noise levels caused by the machine, and involved 5 volunteers twice in each set of the experiments. The physiological study results confirmed the fact that the occupational conditions caused considerable shifts in vibration sensitivity and markedly influenced the peripheral vessels. Through a set of regression equations it was proved that local vibration and noise were mostly responsible for the functional shifts.

Adult↗
PubMed1991

[Biological rhythms of tissue basophils of the dura mater of rats under the effects of noise-vibration].

The biorhythmologic changes of tissue basophils (mast cells) have been investigated of mater rats in frontal, temporal and occipital regions of dura mater during the noise-vibration stress. Local differences were found in biorythmological characteristics of tissue basophils before and after vibration. The investigated regions of dura mater after noise-vibration stress the magnitude of harmonics, mesor and the amplitude of fluctuations increased greatly. But, judging by their values, in the temporal region the rhythm stability was lower than that in the frontal and occipital. The tissue basophils of various regions of dura mater react in a different way to the noise-vibration stress.

Animals↗
PubMed1991

Electrolytic exchange in organism under the conditions of vibration. Experimental studies.

The study deals with a wide spectrum of indices of the electrolytic metabolism--sodium, potassium, calcium, chlorides, magnesium, iron, copper, zinc, cobalt and manganese--in blood, organs and tissues under the conditions of experimental chronic exposure of whole-body vibration frequency of 50 and 150 Hz and velocity of 85 mm.s-1 during a three months experiment (3 h daily) Reference methods were used for the determination of the indices--atom absorption spectrophotometry (variants with flame and without flame), coulometric chlorine titrator, flame photometry, etc. The indices were examined three times (1, 2 and 3rd months). Statistic analysis of the data showed significant changes in the number and the values of the indices and their character (increase or decrease) in comparison with the control values. The indices modifications occur early (at the end of the first month) and they proceed till the end of the experiment (till the end of the 3rd month) during the exposure to both frequencies, but are strongly expressed in the case of high frequency vibrations. The disorders in electrolytic metabolism established in the experiment testify that people exposed to vibrations are likely to suffer analogical changes and develop other pathologies--diseases of cardiovascular system, of blood and haematopoietic organs, etc. as well as an increase of specific disorders in connection with vibration exposure.

Animals↗
PubMedDate not supplied

[The turning reflex, static endurance and structure of the vestibular apparatus receptors in rats exposed to whole-body low-frequency vibration].

Wistar rats were for 2 weeks exposed to vibrations of 18 Hz (acceleration of 2.3 G applied for 5.8 hrs a day for as long as 58 hrs) and 30 Hz (acceleration of 9.6 G applied for 5.1 hrs a day for as long as 56 hrs). The weight gain of experimental animals was less than that of control rats. Static endurance measured in terms of the time, during which the rats stayed on the vertical pole, decreased in the controls as their weight grew. Static endurance of the experimental rats remained essentially unchanged in spite of their growth. This may be associated with the stimulating effect of vibration on the muscle tone. The turning reflex was investigated using a specially designed unit, which allowed stroboscopic photography that was synchronized with the moment, when the animal began to fall down. The angles between the head and torso as related to the horizontal line were calculated and found to be unaltered in both experimental and control animals during 2 weeks. However, after exposure to vibration of both magnitudes the rats began to position the body off the horizontal line. Morphological examinations revealed no distinct structural changes in the utriculus, sacculus or posterior ampulla of the experimental rats when compared with the controls. At the same time it was demonstrated that the exposure produced swelling of cupulate nerve endings in the central compartment of the receptor epithelium of the posterior ampulla. The time course of morphofunctional changes of the vestibular apparatus in response to vibration of different frequencies (from 6 to 50 Hz) was also examined.

Animals↗
PubMed1991

[Occupational morbidity due to the effects of vibration and noise in leading USSR industries and main objectives of its prevention].

The article presents data on the prevalence and dynamics of noise and vibration related occupational morbidity in different regions of the USSR, branches of industry and professional groups. Diseases caused by noise and vibration present major and ever growing occupational pathology in the Soviet Union. Particularly high morbidity rates were traced in the Russian Federation, Ukraine, Kazakhstan and Lithuania, primarily in coal mining, metallurgy, machinery construction branches of industry, and, as to occupational hypoacusis,--in metallurgy, some branches of machinery construction, automobile construction and light industry. Vibration related risk factors were revealed in such professional groups as choppers, emery polishers, tool sharpeners, loggers, drill operators; noise related risk factors--in blacksmith's works, weaving and some others. Certain decrease in occupational morbidity rate was registered before 1985 with a tendency to increase in the last 4-5 years. Prevention of vibration and noise related morbidity should include complex measures, modernization of industrial sites and health services improvement.

Female↗
PubMed1990

[Changes of vibration frequency due to root resorption of deciduous tooth].

The purpose of this study was to investigate the changes of vibration frequency of a deciduous tooth due to physiological root resorption. The author developed an analysis system for tooth vibration by applying an impact-hammer to the tooth. Peak frequency (Hz) of the tooth stimulated by the impact-hammer was observed by the analysis system. The following results were obtained: 1) Peak frequency of the tooth vibration shifted to a lower range according to the root resorption both in vitro (simulation model) and in vivo (15 children) and a high positive correlation was found between the peak frequency and the crown-root length ratio (r = 0.840). 2) A cause of the frequency shift to the lower range was not related to the tooth weight but to the change of tooth gravity due to the root resorption. 3) It was considered that the vibration analysis system could be useful on measuring tooth mobility in vivo and in clinic as well.

Child↗