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PubMed1980

[Blood serum viscosity in patients with advanced vascular forms of vibration disease].

In 35 persons afflicted by advanced angioneurotic vibration syndrome, with no contact with mechanical vibrations for the past several years and recognized invalidity due to vibration disease, specific and reduced blood serum viscosity have been determined, as well as total protein concentration and albumin to globulin concentrations ratio. Control groups were composed of 32 healthy subjects, with no contact with vibration or any other environmental hazards, as well as of 57 professionally active subjects, afflicted by angioneurotic vibration syndrome. A significant increase in specific and reduced viscosity in the group with advanced angioneurotic vibration syndrome, as compared to both the remaining groups, was found. At the same time, the albumin-globulin concentrations ratio was found to be decreased, the total protein concentration remaining unaltered.

Adult↗
PubMed1995

Vibration and noise in pediatric emergency transport vehicles: a potential cause of morbidity?

BACKGROUND: Noise and vibration are stressors that may adversely affect the well-being of infants and children being transported between facilities. Although the problem has been recognized, little has been done to rectify the situation. HYPOTHESIS: That noise levels in transport incubators during use in transport vehicles exceed the recommended standards, and that vibration levels exceed those that are "very uncomfortable" for healthy adults. METHODS: We measured noise and vibration (n/v) levels inside and outside a neonatal transport incubator in seven transport vehicles (land, air, and water), and calculated maximum and average, weighted and unweighted levels. RESULTS: The maximum and average unweighted noise levels in all but one vehicle were over 99 dB. The incubator amplified noise at the lower frequencies (The Canadian Standards Association 1992 recommendation is that the noise level in transport incubators not exceed 60 dBA). The maximum vibration levels ranged from 0.86 m.S-2 to 2.35 m.S-2, and the average levels ranged from 0.33 m.S-2 to 1.46 m.S-2. (Vibration in excess of 1.5 is considered "very uncomfortable," and in excess of 2.0 is "extremely uncomfortable" for healthy adults.) CONCLUSIONS: Noise and vibration levels inside transport incubators in our most-commonly used transport vehicles often exceed the recommended limits. For neurologically immature and/or physiologically compromised infants and children, current levels of n/v in transport vehicles are too high, and could affect patient morbidity. These n/v levels require further study, and modification of equipment, primarily the incubators, is overdue.

Air Ambulances↗
PubMed1994

Vibration exposure and prevention in the United States.

There are over one million workers exposed to hand-arm vibration in the United States. Cases of hand-arm vibration syndrome have been reported in the U.S. since 1918. Typical hand-arm vibration exposure conditions are given in this presentation. Vibration control methods are discussed; these include vibration damping and isolation, use of antivibration (A/V) tool and gloves, and the application work practices and hand-arm vibration standards in the workplace.

Humans↗
PubMed1994

Research into hand-arm vibration syndrome and its prevention in Japan.

Research on vibration syndrome in Japan began in the 1930s with studies of the disorder among railway, mining and shipyard workers. In 1947, the Ministry of Labor decided vibration syndrome among operators of rock drills and riveters etc. was an occupational disease. Industrial developments in the 1950s and 1960s promoted the survey of vibration syndrome in mining, stone quarrying and forestry. The Ministry of Labor (1965) and the National Personnel Agency (1966) legally recognized vibration syndrome among chain saw operators as an occupational disease. Guidelines for prevention and early therapy were issued in the 1970s and 80s. From the late 1970s into the 1980s, research focused on the clinical picture, diagnostic methods and therapy. In pathophysiology, advances were made in research into the autonomic nervous system during the 1980s. The 1970s and 80s saw a steady reduction in risk from technological change and working conditions, and advances in medical care, education and meteorological forecasting. A comprehensive prevention system established in the 1980s in the Japanese forest industry involved: 1) work restrictions, 2) an improved health care system, 3) advances in the design of vibrating tools, handle-warming devices, and 4) improved worker education. This comprehensive preventive system was legally introduced into other industries, resulting in a rapid decrease in the incidence of vibration syndrome in Japan.

Arm↗
PubMed1994

Sympathetic responses to hand-arm vibration and symptoms of the foot.

Vibration syndrome is generally considered to consist of disorders in the upper extremities which are directly exposed to vibration. However, it has been shown that vibration syndrome patients have circulatory disturbances in the foot as well: several chain-saw operators, who were little exposed to vibration of the foot, had Raynaud's phenomenon of the toes, and those with frequent attacks of vibration-induced white finger (VWF) had a higher prevalence of coldness felt in both the hands and the feet, and the patients with VWF had lower skin temperature of the toes as well as the fingers. Moreover, arterial pathological changes like medial muscular hypertrophy have been observed in both the fingers and the toes of the patients. Hand-arm vibration elicits a sympathetic nervous reflex, leading to vasoconstriction of the four extremities. Long-term repeated vasoconstriction may result in such arterial changes and then circulatory disturbances of the feet.

Arm↗
PubMed1994

Whole body vibration and the snowmobile.

The whole body vibration from the seat and foot board was measured during ten years from 11 different snowmobiles to evaluate the exposure and the need for technical improvements. In a questionnaire more than half of the drivers had back pains but only a few of them considered the whole body vibration as a health hazard. However in the literature there is often comments on spinal injuries related to shock vibration. The frequency-weighted acceleration of snowmobile vibration was from 1 to 6.1 m/s2 and the risk evaluation using the ISO standard predicted the problems. Speed and the unevenness of the driving terrain caused vibration. The damping depends on the properties of the seat, terrain and speed limits. Also the driving posture is important. Especially on the snowmobile tracks the whole body vibration was high and according to modern knowledge more attention should be paid the technical properties of snowmobiles.

Humans↗
PubMed1994

Vibration sensibility testing in the workplace. Day-to-day reliability.

Loss of vibration sensibility has been suggested as an early indicator of peripheral compression neuropathy, including carpal tunnel syndrome. Although vibration sensibility has been used frequently to evaluate carpal tunnel syndrome, the day-to-day reliability of vibration measurements in an industrial population measured at the workplace has not been assessed. Vibration sensibility testing was performed at the university ergonomics laboratory on 50 volunteers (100 hands) and at a newspaper company on 50 workers (100 hands). Vibration perception and disappearance thresholds were measured on two occasions separated by 3 to 5 days. Student's t tests indicated no significant differences between the first and second tests or between the two groups. Pearson product-moment correlations for test-retest reliability were lower in the industry group but were relatively high despite the less than optimal testing conditions. Our findings suggest that vibration sensibility measurements are reliable from day to day not only in the laboratory but also in the workplace.

Adult↗
PubMed1994

Vibration arthrometry of the knee with torn meniscus: a preliminary report.

Although projects using vibration signals generated by the joint to detect joint disorders are still experimental, vibration arthrometry has been shown to be useful in assessing meniscal pathology. A prospective study using vibration arthrometry to diagnose meniscal tears was carried out in 25 consecutive patients with knee injuries. They comprised 20 males and five females with an average age of 34 years. An arthroscopic examination of the injured knee was given to every patient. Six cases of medial meniscal tear, 12 lateral meniscal tear, and two torn discoid menisci were found. The remaining five cases had normal menisci. By correlating the vibration arthrography of the patients to their corresponding arthroscopic findings, 15 were found to be true-positive, five true-negative and five false-negative. There were no false-positive readings. The accuracy, sensitivity and specificity of the vibration arthrometry in diagnosing meniscal tear was 80%, 75% and 100%, respectively. Vibration arthrometry was shown to be a reliable, non-invasive diagnostic tool in diagnosing meniscal tear of the knee.

Adolescent↗
PubMed1994

The influence of biodynamic factors on the absorption of vibration energy in the human hand and arm.

A possible basis for risk assessment for hand-transmitted vibration may be to determine the quantity of energy absorbed in the human hand and arm. In the present study the mechanical energy absorption in the hand-arm system has been measured on 10 healthy subjects during exposure to random vibration with constant velocity spectrum. In the study, the influence of various conditions, such as vibration direction (Xh, Yh, Zh), grip force (25-75 N), feed force (20-60 N), frequency weighted acceleration level (3, 6, 9, 12 m/s2) and hand and arm posture (5 flexions, 2 abductions) were studied. The outcome showed that the energy absorption in the human hand and arm depended mainly on the frequency and direction of the vibration stimuli. Higher vibration levels, as well as firmer hand grips and higher feed forces, resulted in a significantly higher absorption. As concerns the hand and arm posture the results show that the flexion had a significant contribution to the vibration absorption but the abduction had no influence on the quantity of absorbed energy. Furthermore, the influence of some of the studied variables had a non-linear effect on the absorption but also differed between different exposure directions. Moreover, it was concluded that the frequency-weighting routine in the international standard ISO 5349 do not reflect the energy absorbing properties of the human hand and arm.

Absorption↗
PubMed1996

[Correlation of changes in the electrical activity and indices of tissue respiration of brain structures in rabbits exposed systematically to vibration].

The electrical activity and tissue respiration of the cortex and subcortex (posterior hypothalamic nucleus, Deiters' vestibular nucleus) have been studied in the rabbits during 3-month exposure to vibration (60H2, for 3h daily). On days 15-30 of exposure to vibration the electrocorticogram demonstrated the prevalence of alfa-waves whereas in the subcortex the teta-waves were dominated. On long-term vibration exposure (2-3 months), the synchronized slow waves were recorded on the EEG. Comparison of a changed electrical activity of the various structures of the brain with the level of oxidizing metabolism enabled us to reveal their definite interrelationship. In the early stage of vibration exposure there has been observed an increased absorption of oxygen by the brain structures and the elevated activity of succinate dehydrogenase. The prolonged vibration resulted in a decreased level of tissue respiration and activity of respiratory enzyme. Under vibration exposure there has been revealed a statistically significant direct relationship between the content of absorbed oxygen, activity of succinate dehydrogenase and the shifts in the electrical activity of cerebral structures.

Animals↗
PubMed1995

Age-related evaluation of peripheral circulation of workers with vibration exposure.

This study was designed to clarify the age variation of the indices in the accelerated plethysmography (APG) for fingers and set the standard ageing curve. The indices of APG of workers with exposure to vibration were compared with those of the standard ageing curves. The subjects were 815 male workers, ranging in age from 18 to 66, without exposure to vibration and without history of hypertension, circulatory diseases or diabetes. Their indices of APG are used establishing the standard ageing curves. The workers occupationally exposed to hand-arm vibration were also the subjects to evaluate peripheral circulation of hand. The APG was measured on the index finger tip of his dominant side by an accelerated plethysmometer. The subjects were divided into age groups at intervals of 5 years. In all age groups from 18 to 64 years, each index of APG showed an approximately normal distribution in a logarithmic scale. The mode of the distribution shifted to a lower value with increasing age. The standard ageing curves were drawn by calculating 25th, 50th and 75th percentiles by a nonparametric method for each group. Each index of the standard ageing curves dropped with increasing age. The significant age effect was slightly marked below 30 years, but marked between 30 and 50 years. The indices of APG of workers with exposure to vibration were also compared with those of the standard ageing curve. The indices of -b/a and a/d of workers with exposure to vibration were deteriorated beyond physiological change. We established the standard ageing curves for APG for male men. The technique is good for the evaluation of peripheral circulation disorder of aged workers with occupational exposure to vibration.

Adult↗
PubMed1995

Hand-arm vibration in tropical rain forestry workers.

Working conditions and health hazards including vibration syndrome related to forestry work using chain-saws were studied in Papua New Guinea and Indonesia. The subjects comprised 291 workers including 97 chain-saw operators. The health examination consisted of peripheral circulatory and sensory tests in the upper extremities. The vibration spectrum measured at the handle of the chain-saw indicated that these acceleration levels would lead to a moderately high risk of hand-arm vibration syndrome (HAVS). The peripheral circulatory function tests revealed dysfunction after more than five years vibration exposure. However, in general, the results of the function tests and subjective complaints showed fewer health problems compared to those of Japanese forestry workers. The reason of such differences of vibration effects seem to be the following: (1) warmer climate (more than 25 degrees C throughout the year), (2) young workers and short work experience. (3) short time vibration exposures on working days in the natural forests, (4) seasonal changes in logging work (5) healthy workers effects. Thus, we found no clear evidence that the workers of our study suffered from HAVS. A principal component analysis was applied. The factor score of the components of the reactive dynamics of peripheral circulation differed significantly after more than five years' exposure. On the other hand, we cannot deny the possibility that subclinical dysfunction of peripheral circulation may be caused by chain-saw operation in the tropics in future. Further investigations on the HAVS among forestry workers in the tropic environment are needed.

Adult↗
PubMed1995

Hand-arm vibration and terrain vehicles.

Hand-arm vibration was measured on the handlebars of terrain vehicles (N = 36) and a postal inquiry was made among N = 2705 reindeer herders (snowmobile drivers). Since many subjects had also used other vibrating tools the snowmobile group proper (N = 334) was established. In the whole group 19% of the subjects reported having experienced white finger attacks and 48% numbness of the hands. The frequency-weighted acceleration of snowmobile vibration was 3.5 m/s2, and risk evaluation using the ISO 5349 standard predicted the prevalence of white finger well in the snowmobile group proper. The vibration levels were 1.6-7.9 m/s2 on snowmobiles, 5.5-11.8 m/s2 on all-terrain vehicles and 6.9-12.7 m/s2 on terrain motorcycles. The most critical points for damping the vibration were the motor mounting and resonance in the steering yoke. There is need for health care, technical improvements, and other protection means to reduce the symptoms of vibration in driving terrain vehicles.

Adult↗
PubMed1998

Equivalent sensation curves of simultaneous lateral and vertical sinusoidal whole-body vibration.

BACKGROUND: To evaluate the effects of whole body vibration on discomfort, the sensitivity to different frequencies as well as to different vibration axes must be regarded. This experimental study investigates the significance of lateral relative to vertical motions in the sensation of dual axis sinusoidal vibrations in sitting posture. The results are discussed in the context of the evaluation procedure proposed in the international standard ISO 2631 (13). METHODS: The experiments, in which 31 volunteers (16 female, 15 male, 19 51 yr) participated, used the method of adjustment. The subjects compared a single axis reference motion (aw = 1.25 ms(-2) rms) with a dual axis test motion of the same frequency. The magnitude of the test signal's component along the reference axis was kept constant at a fractional level of the reference magnitude (10, 25, 50, 75 or 90%). The component perpendicular to the reference axis was adjusted by the subjects until the test signal was rated as being equally strong as the reference. Both vertical and lateral reference motions were applied. The frequencies used were 1.6, 3.15, 6.3 and 12.5 Hz. RESULTS: The shape of the resulting right-downwards bent equivalence curves was reasonably well fitted using the frequency weightings and evaluation procedure of ISO 2631. However, there were considerable quantitative discrepancies for frequencies above 1.6 Hz with an underestimation of the effects of lateral vibrations by a factor of 1.5-2. Therefore, it is concluded that lateral vibrations above 1.6 Hz need more weight in the evaluation of discomfort caused by multi-axis whole body vibrations.

Acceleration↗
PubMed2004

Computational study of the vibrational spectra of alpha- and beta-Keggin polyoxometalates.

The structures and vibrational frequencies of the alpha- and beta-isomers of the phosphomolybdate Keggin anion [PMo(12)O(40)](3-) have been calculated by using density functional theory. Good agreement between the calculated unscaled vibrational frequencies and those determined experimentally and between the calculated and observed IR traces has been obtained allowing the IR and Raman spectra to be assigned. For the alpha-isomer, the agreement with experiment using the current level of theory is superior to that obtained previously. For the beta-isomer, for which no non-empirical study has previously been reported, the agreement with experiment is slightly poorer but still allows the spectrum to be assigned unambiguously. To calculate the structure and vibrational spectra of these large molydate cluster ions requires large basis sets and a good treatment of electron correlation and relativistic effects. For the 53-atom [PMo(12)O(40)](3-) ions, the computational demands are very high, requiring several months computational time. The calculated IR spectral traces for the two isomers are quite similar due to the relative flexibility of the molybdates, where the slight weakening of the bonding of the rotated trimetallic unit to the rest of the cluster in the beta-isomer is compensated by contraction of the bonds within the unit, and the structure of the [MO(6)] and [PO(4)] units in the two isomers is nearly identical. The vibrations characteristic of the bridging Mo-O-Mo bonds involve both the "2-2" junctions between rotated [M(3)O(13)] units and the "1-2" junctions between rotated and unrotated units. The separation of "ligand" and "interligand" vibrations is not clear. The vibrational analyses confirm the high symmetry, namely T(d) and C(3v) for the alpha- and beta-isomers, respectively, assumed by previous workers in this field. The characteristic group frequencies for the Type I polyoxometalates containing both edge- and corner-sharing I octahedra have been identified.

Journal Article↗
PubMed1999

Analysis of Rotational Transitions in Excited Vibrational States of Propionitrile (C2H5CN).

We have observed rotational transitions of propionitrile (C2H5CN) in the 8-200 GHz region and assigned 208 transitions with J </= 16 and Ka </= 2 in the first excited state of torsional vibration, 244 transitions with J </= 16 and Ka </= 2 in the first excited state of CCN in-plane bending vibration, and 374 transitions with J </= 16 and Ka </= 4 in the first excited state of CCN out-of-plane bending vibration. We simultaneously analyzed these transitions in the three excited vibrational states, combining with the previously reported transitions in the ground vibrational state, on the basis of a Hamiltonian including CCN-bending vibration-torsion-rotation interactions. A total of 1560 transitions were fitted with 0.95-MHz 1varsigma standard deviation, and molecular constants were determined. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

New Vibrational Numbering and Potential Energy Curve for the 3(3)Pig Electronic State of the Li2 Molecule.

An experimental study of the 3(3)Pig electronic state of 7Li2, using the Perturbation-Facilitated Optical-Optical Double Resonance (PFOODR) technique, was recently reported [A. Yiannopoulou et al., J. Chem. Phys. 103, 5898, (1995)]. However, due to the very small number of known 7Li2 A1Sigma+u approximately b3Piu window levels, only 13 ro-vibrational levels (spanning a range of vibrational levels designated upsilonx - 1 to upsilonx + 3 in that reference) could be observed. Dunham coefficients, based on the assignment upsilonx = 7, were found to fit the observed term values and give a qualitative fit to the intensities of the first six lines of the 3(3)Pig (upsilon = upsilonx, N = 11) --> b3Piu emission spectrum. However, due to the limited number of levels used in the fit, both the absolute vibrational numbering and the 3(3)Pig RKR potential curve obtained from the Dunham coefficients, must be considered to be uncertain. In the present work, we show that the previously reported 3(3)Pig RKR curve is unable to reproduce the experimental intensity distribution in the 7Li2 3(3)Pig (upsilonx = 7, N = 11) --> a3Sigma+u emission continuum. We report new experimental data for the 7Li2 3(3)Pig (upsilonx + 1, N = 11) --> a3Sigma+u bound-free continuum and discrete 3(3)Pig (upsilonx +/- 1, N = 11) --> b3Piu spectra obtained using the PFOODR experimental technique. We demonstrate that the correct vibrational numbering and an improved RKR potential curve can be obtained by analyzing the experimental term values in combination with all observed bound-free and discrete spectra. Finally, term values for four 6Li2 3(3)Pig ro-vibrational levels were obtained using PFOODR spectroscopy. The measured isotope shifts confirm the absolute vibrational numbering obtained from the present analysis. Copyright 1999 Academic Press.

Journal Article↗
PubMed1994

Low-back disorders in agricultural tractor drivers exposed to whole-body vibration and postural stress.

The occurrence of low-back pain (LBP) was investigated in a population of 1155 tractor drivers exposed to whole-body vibration (WBV) and postural stress (response rate 91.2%) and in a control group of 220 office workers (response rate 92.2%). The subjects were questioned about several types of low-back symptom (LBP, sciatic pain, acute LBP, transient and chronic LBP) and various work- and individual-related risk factors, by using a standardized questionnaire. Vibration measurements were performed on a representative sample of the vehicles driven by the tractor drivers in the last ten years. Vibration magnitude and duration of exposure were used to calculate a vibration dose for each tractor driver. Perceived postural load was assessed in terms of frequency and/or duration of awkward postures at work. The prevalence of LBP was found to be greater in the tractor drivers than in the controls. After controlling for potential confounders by logistic modelling, low-back disorders were found to be significantly associated with both vibration dose and postural load. Back accidents and age were also significant predictors for LBP. Quantitative regression analysis indicated that vibration exposure and postural load were independent contributors to the increased risk for LBP according to a multiplicative model. The exposure levels for WBV recently recommended by a proposal of European Directive on physical agents seem to be more adequate to prevent long-term health effects on the lower back than the exposure limits suggested by the International Standard ISO 2631/1.

Journal Article↗