Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “VIBRATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed2005

The effectiveness of using two different types of anti-vibration gloves compared to bare hand condition at dampening the frequencies associated with hand-arm vibration syndrome.

The ability of a foam-padded and air-bladder glove to significantly attenuate hand-arm vibration compared to an individual's bare hands (after the effect of adipose content of the distal upper extremity had been removed) was studied. Subjects consisted of 3 male and 8 female university students' aged 20 to 22 years. After the effect of adipose content of the distal upper extremity was removed, the effect of the gloves on transmissibility was significant with F2,959 = 5.27, p<0.000. The effect of the frequencies was significant with F31,959 = 8.80, p<0.000. There was no significant interaction between the gloves and frequencies on transmissibility with F62,959 = 0.22, p = 1.000. Post-hoc analysis revealed that there was a significant difference was between bare hand and foam-padded glove conditions, F1,1052 = 8.13, p = 0.004, where foam-padded gloves had significantly greater transmissibility. Post-hoc analysis of the frequencies indicated that there were significant differences between frequencies at with the highest transmissibility occurring at 100 Hz.

Adult↗
PubMed1991

[Cell-membrane aspects of the pathogenesis of hypoxia in vibration disease induced by local vibration].

A study was made of the blood and tissue oxygen regime in patients with vibratory disease (VD) induced by local vibration and of the importance of lipid peroxidation (LPO) in oxygenation disorders. Venous hyperoxia, a decrease of the arteriovenous difference according to oxygen, the percentage of oxygen utilization by tissues, shift of the acid-base balance towards metabolic acidosis were established, attesting to tissue hypoxia that increased with the gravity of VD. The importance of a steady activation of LPO and depression of the antioxidant system in the pathogenesis of hypoxia associated with VD was supported by the correlation analysis data on oxygen balance and LPO, the functional and metabolic characteristics of red blood cells (according to the viscosity of red blood cell suspension and the content in the cells of SH-groups, lipoproteins and histidine) and platelets (according to aggregation in response to ADP and thrombin) as well as by the level of blood serum fluorescence. The authors provide evidence for the use of antioxidants (a complex of alpha-tocopherol with ascorbic acid and methionine and calcium antagonists of the nifedipine group), giving a membranostabilizing effect, in multimodality treatment of patients afflicted with VD.

Acid-Base Imbalance↗
PubMed1989

[Clinical aspects of vibration disease caused by general vibration].

The clinico-functional examination of agricultural machine-operators, truck drivers, excavator and boring machine operators revealed that, under low-frequency general vibration, polymorphic pathologic changes occur in human organism. Those include peripheral vascular and neuritic disorders and changes in the vertebral column. The most peculiar symptoms of VD are dealt with. The data obtained show to the importance of further elaboration of differential diagnostic criteria of VD, specifying its pathogenic mechanisms and prevention measures working out.

Diagnosis, Differential↗
PubMed1994

Hand-arm vibration exposure and the development of vibration syndrome.

To evaluate the circulatory disturbances, sensory disturbances and damage to muscles and joints by chain saw vibration exposure, the process of the deterioration of the symptoms with chain saw operating time was studied. Subjects were classified into eight groups according to TOT (Total Operating Time): Group 0, 46 controls; Group A, 39 operators (< 2,000 hours); Group B, 53 operators (2,000-4,000 hours); Group C, 45 operators (4,000-6,000 hours); Group D, 29 operators (6,000-8,000 hours); Group E, 31 operators (8,000-10,000 hours); Group F, 35 operators (10,000-15,000 hours); and Group G, 34 operators (> 15,000 hours). The subjective symptoms and clinical findings due to operating chain saws were divided into three main categories of peripheral circulatory disturbances, sensory disturbances and damage to muscles and joints. According to the criteria, the total score of each disturbance was calculated per individual in Group 0 and Groups A through G, respectively. The scores for the three (circulatory, sensory, muscles and joints) disturbances increased significantly with the increase of TOT. The scores for circulatory disturbances increased significantly in Group A and B, as compared with those in its previous Group, respectively. The scores for sensory disturbances increased significantly in Groups A, B, and F. The scores for damage to muscles and joints increased significantly in Group B.

Arm↗
PubMed1998

Molecular Structures, Vibrational Spectroscopy, and Normal-Mode Analysis of M(2)(C&tbd1;CR)(4)(PMe(3))(4) Dimetallatetraynes. Observation of Strongly Mixed Metal-Metal and Metal-Ligand Vibrational Modes.

The nature of the skeletal vibrational modes of complexes of the type M(2)(C&tbd1;CR)(4)(PMe(3))(4) (M = Mo, W; R = H, Me, Bu(t)(), SiMe(3)) has been deduced. Metrical data from X-ray crystallographic studies of Mo(2)(C&tbd1;CR)(4)(PMe(3))(4) (R = Me, Bu(t)(), SiMe(3)) and W(2)(C&tbd1;CMe)(4)(PMe(3))(4) reveal that the core bond distances and angles are within normal ranges and do not differ in a statistically significant way as a function of the alkynyl substituent, indicating that their associated force constants should be similarly invariant among these compounds. The crystal structures of Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) and Mo(2)(C&tbd1;CBu(t)())(4)(PMe(3))(4) are complicated by 3-fold disorder of the Mo(2) unit within apparently ordered ligand arrays. Resonance-Raman spectra ((1)(delta-->delta) excitation, THF solution) of Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) and its isotopomers (PMe(3)-d(9), C&tbd1;CSiMe(3)-d(9), (13)C&tbd1;(13)CSiMe(3)) exhibit resonance-enhanced bands due to a(1)-symmetry fundamentals (nu(a) = 362, nu(b) = 397, nu(c) = 254 cm(-)(1) for the natural-abundance complex) and their overtones and combinations. The frequencies and relative intensities of the fundamentals are highly sensitive to isotopic substitution of the C&tbd1;CSiMe(3) ligands, but are insensitive to deuteration of the PMe(3) ligands. Nonresonance-Raman spectra (FT-Raman, 1064 nm excitation, crystalline samples) for the Mo(2)(C&tbd1;CSiMe(3))(4)(PMe(3))(4) compounds and for Mo(2)(C&tbd1;CR)(4)(PMe(3))(4) (R = H, D, Me, Bu(t)(), SiMe(3)) and W(2)(C&tbd1;CMe)(4)(PMe(3))(4) exhibit nu(a), nu(b), and nu(c) and numerous bands due to alkynyl- and phosphine-localized modes, the latter of which are assigned by comparisons to FT-Raman spectra of Mo(2)X(4)L(4) (X = Cl, Br, I; L = PMe(3), PMe(3)-d(9))(4) and Mo(2)Cl(4)(AsMe(3))(4). Valence force-field normal-coordinate calculations on the model compound Mo(2)(C&tbd1;CH)(4)P(4), using core force constants transferred from a calculation on Mo(2)Cl(4)P(4), show that nu(a), nu(b), and nu(c) arise from modes of strongly mixed nu(Mo(2)), nu(MoC), and lambda(MoCC) character. The relative intensities of the resonance-Raman bands due to nu(a), nu(b), and nu(c) reflect, at least in part, their nu(M(2)) character. In contrast, the force field shows that mixing of nu(M(2)) and nu(C&tbd1;C) is negligible. The three-mode mixing is expected to be a general feature for quadruply bonded complexes with unsaturated ligands.

Journal Article↗
PubMed2001

Linear response of vibrated granular systems to sudden changes in the vibration intensity.

The short-term memory effects recently observed in vibration-induced compaction of granular materials are studied. It is shown that they can be explained by means of quite plausible hypothesis about the mesoscopic description of the evolution of the system. The existence of a critical time separating regimes of "anomalous" and "normal" responses is predicted. A simple model fitting into the general framework is analyzed in the detail. The relationship between this paper and previous studies is discussed.

Journal Article↗