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At least 145 records · Page 8Linked to original sources
PubMed2001

Risk of hand-arm vibration syndrome according to occupation and sources of exposure to hand-transmitted vibration: A national survey.

BACKGROUND: Although some occupational sources of hand-transmitted vibration (HTV) have been extensively investigated, the risks associated with others are poorly characterized. METHODS: A questionnaire was mailed to a community sample of 12,240 men aged 16- 64 years and 906 men from the armed forces. Questions covered current occupation, sources of HTV, numbness or tingling in the fingers in the past week, and finger blanching. In the 5,364 respondents who had been at work in the past week, associations between symptoms and exposures were examined by logistic regression, with odds ratios converted into prevalence ratios (PRs). RESULTS: Altogether, 513 men (10%) reported cold-induced finger blanching and 769 (14%) sensory symptoms in the fingers. The risk of blanching was increased in builders (PR 2.4, 95% CI 1.0-5.2), carpenters and joiners (PR 1.9, 95% CI 1.0-3.4), motor mechanics (PR 2.3, 95% CI 1.1-4.6), and laborers (PR 2.8, 95% CI 1.3-6.0); while the risk of sensory symptoms was elevated in laborers (PR 4.0, 95% CI 2.3-6.6) and plant operatives (PR 3.5, 95% CI 1.9-5.9). Use of hand-guided mowers, concrete breakers, chain saws, and jig saws was significantly associated with symptoms. CONCLUSIONS: Little attention has been paid to the risks of vibration injury in construction workers, woodworkers, motor mechanics, and laborers, or to the risks from mowers, jig saws and several other common vibratory tools. These should be a focus for further investigation and preventive measures.

Adolescent↗
PubMed1994

An epidemiologic study of carpal tunnel syndrome and hand-arm vibration syndrome in relation to vibration exposure.

No Minnesota workers' compensation claims have been filed for permanent partial disability benefits with a diagnosis of hand-arm vibration syndrome (HAVS). A cross-sectional study was undertaken to evaluate 519 compensation claimants following carpal tunnel surgery. Workers with significant vibration exposure and symptoms compatible with HAVS were identified within the group. The results show that some workers are not diagnosed as having HAVS even though they meet the diagnostic criteria. This suggests that HAVS should be considered in the differential diagnosis when a worker presents with neural and/or vascular symptoms of the hands and fingers.

Adolescent↗
PubMed2004

Vibrational states of tetrahedral molecular species in electric fields. A theoretical model for quantitative description of the latent symmetry effects in vibrational spectroscopy of matrix isolated tetrahedral species.

A theoretical model that enables a quantitative description of latent symmetry effects in the case of matrix isolated tetrahedral species is developed. Several particular cases are considered, that are of special interest from vibrational spectroscopic viewpoint. It is shown that the observed appearances of the IR spectra of various XY4n- anions isomorphously isolated in solid matrices may be systematically explained in terms of the orientation of the effective local crystalline field vector. The model also principally enables calculation of the magnitude of the effective local homogeneous field vector as well as its direction with respect to the symmetry elements of the dopant species, and it can be successively corrected accounting for the field non-homogeneity. Also, a solid theoretical basis is for the first time presented for the significantly smaller site group splitting of the nu4 modes of dopant XY4n- species in comparison to the splitting of nu3 ones, which is often observed in the IR spectra. However, the presented approach has potentially a much wider applicability, as it in facts considers the vibrational states of tetrahedral molecular species in electric fields, which may be of a different origin, for example, electrodes in electrochemical systems, external fields in Stark-type spectroscopies, etc.

Electricity↗
PubMed2005

Vibrational dephasing and hydrodynamic effects on vibrational relaxation rates in acetophenone: Raman bandshape analysis.

The isotropic component of Raman band for C=O stretching mode of acetophenone in solution was analyzed by estimating the correlation coefficient with reference to Lorentzian lineshape. In the intermediate region of solute/solvent concentration there is a sharp decrease in the correlation coefficient and there appears to be a transition from non-Lorentzian to Lorentzian lineshape. The vibrational relaxation rates have been estimated from the isotropic component of Raman band in different solvents. The rate is shown to be dependent on several macroscopic as well as microscopic properties of the solute-solvent system and intermolecular interactions. The hydrodynamic and dispersion forces appear to play a major role in determining the vibrational relaxation rate and the broadening of the bands.

Acetophenones↗
PubMed2006

DNA vibrational coupling revealed with two-dimensional infrared spectroscopy: insight into why vibrational spectroscopy is sensitive to DNA structure.

Two-dimensional infrared (2D IR) spectroscopy was used to study the carbonyl vibrational modes of guanine and cytosine bases in A- and B-form DNA. Located between 1600 and 1700 cm(-1), these modes are often used to monitor DNA secondary structure with traditional infrared spectroscopies such as FTIR, but traditional spectroscopies lack the necessary observables to unravel the coupling mechanisms that make these modes sensitive to secondary structure. By using 2D IR spectroscopy and electronic structure calculations on d(G(5)C(5)) and d(GC)(8) model nucleic acids, we find that hydrogen-bonded guanine/cytosine base pairs are primarily electrostatically coupled and that the coupling between these modes can be modeled with a transition dipole density approach. In comparison, electrostatics is insufficient to model stacked bases because of cooperative charge-sharing effects, but the coupling can be accurately calculated using a finite difference method. We find that the coupling is very strong for both hydrogen-bonded and stacked base geometries, creating vibrational modes that extend both across the base pairs and along the lengths of the helices. Our results provide a physical basis for understanding how strong coupling gives rise to the empirically established relationship between infrared spectroscopy and DNA/RNA secondary structure.

DNA↗
PubMed2005

Colloid vibration potential and ion vibration potential in a dilute suspension of spherical colloidal particles.

A general electroacoustic theory is presented for the macroscopic electric field in a dilute suspension of spherical colloidal particles in an electrolyte solution, which consists of the colloid vibration potential (CVP) and the ion vibration potential (IVP), induced by an oscillating pressure gradient field due to an applied sound wave. This is a unified theory that unites previous theories for CVP and those for IVP. Approximate analytic expressions are derived for CVP and IVP. The obtained IVP expression agrees with Debye's formula that is corrected by taking into account the force acting on the electrolyte ions as a result of the pressure gradient in the sound wave. The obtained CVP expression is correct to the first order of the particle zeta potential and applicable for arbitrary kappaalpha, where kappa is the Debye-Hückel parameter and alpha is the particle radius. It is found that an Onsager relation holds between CVP and dynamic electrophoretic mobility. It is also shown that the CVP from particles with very small kappaalpha approaches IVP; that is, in the limit of very small kappaalpha a particle behaves like an ion.

Colloids↗
PubMed1994

Vibrational circular dichroism measurements of ligand vibrations in haem and non-haem metalloenzymes.

We have measured the vibrational circular dichroism (VCD) spectra of the stretching vibrations of azide and cyanide ligated to the Fe3+ atoms of haemoglobin (Hb) and myoglobin (Mb). The antisymmetric azide-stretch of the low-spin haems have an anomalously large g-value of ca. -1 x 10(-3). In contrast, CN- has a g-value of ca. +2.4 x 10(-3). We also show, for the first time, that a significant VCD occurs for the azide ligand antisymmetric stretches of non-haem proteins; we measure a g-value of ca. -1 x 10(-4) for azide bound to haemerythrin. We have examined the mechanism of the VCD phenomenon by: (1) reconstituting Mb with haems substituted such that they insert differently in the haem pocket; (2) replacing the Fe3+ with Mn3+; (3) examining proteins where replacements occur for E-7 His and E-11 Val distal amino acids close to the haem and (4) examining an Mb mutant where the proximal F-8 His is replaced by Gly, and where an imidazole ligand inserts into the resulting crevice and binds to the haem in a way similar to that of the proximal histidine in the native protein. The VCD anisotropy appears insensitive to the haem substituent replacements used in this study. Exchange of the E-7 distal His or the E-11 Val has a dramatic effect on the g-value. Exchange of the F-8 proximal His reverses the sign of the g-value for the azide complex, but not for the cyanide complex. The work to date indicates that VCD has the potential to become a sensitive technique for examining the structure of metalloenzymes. Work is needed to determine the mechanism giving rise to the large g-values and to correlate the VCD spectrum with the metalloenzyme structure at the active site.

Azides↗
PubMed1989

Interpretation of DNA vibration modes: III--The behaviour of the sugar pucker vibration modes as a function of its pseudorotation parameters.

A systematic study of the sugar pucker characteristic vibration modes as a function of its geometrical conformations, has been performed. The present investigation is based on the Wilson GF method and a non-redundant valence force field. The calculated results allow to assign the modes arising mainly from the sugar motions and present in quasi whole vibrational spectra related to the right or left-handed double-helices (i.e., 1050 cm-1, 960 cm-1 and 890 cm-1). Moreover, the conformation dependent modes as those at 860 cm-1 and around 810 cm-1 (A form) as well as the one located around 830 cm-1 (B form) are interpreted by the present investigation. The possibility of the interaction of the latter modes with the phosphate group motions along the DNA double-helical chains are also discussed.

DNA↗
PubMed2004

Vibrational spectra and surface-enhanced vibrational spectra of 1-nitropyrene.

The present report on the vibrational spectra of 1-nitropyrene (1NP) describes the infrared and Raman spectra; their interpretation is aided by local density functional theory (DFT) calculations at the B3LYP/6-311G(d, p) level of theory and by the surface-enhanced vibrational spectra (SEVS) with the final objective of trace organic analytical applications. The surface-enhanced Raman scattering (SERS) on silver island films and mixed silver/gold island films was investigated with several laser lines in the visible region. Surface-enhanced infrared absorption (SEIRA) was attempted on silver and gold island films. The interface of the organic 1-NP with smooth metal surfaces of silver and copper was also probed using reflection-absorption infrared (RAIRS) spectra that, in conjunction with the transmission spectra, allow one to extract the molecular orientation in vacuum evaporated thin solid films. Chemical adsorption of 1-NP on silver and further photochemical decomposition of the 1-NP-metal adsorbates was detected with all visible laser lines. Resonance Raman scattering (RRS) using UV-laser excitation at 325 nm was also recorded.

Air Pollutants↗
PubMed1985

Vibration exposure and vibration-induced white finger due to chain saw operation.

A longitudinal study was undertaken to evaluate changes in the prevalence of vibration-induced white finger (VWF) during the period 1956 to 1980 among a population of Japanese state forestry workers. The vibration levels in the measurements occasionally exceeded the 30-minute line proposed by the Draft International Standard ISO/DIS 5349 in one-third octave bands mainly centered on 160 Hz, with 500 Hz in vertical, 400 Hz in sideways, and 250 Hz in back-and-forth sawing operations. The peak prevalence rate was 62.6%, found in the cohort beginning in 1958-1959. Beginning with the 1968-1969 cohort, the prevalence decreased significantly. During the study period, prevalence rates were approximately 10%, 15%, 20%, 25%, 30%, 35%, and 40% after 2, 3, 4, 5, 7, 9, and 12 years of exposure, respectively. The incidence rate increased gradually after 1960 and the peak value was reached in 1966. The peak value of the incidence rate by duration of exposure was about the same (8% to 10%) in the 1958, 1962, and 1966 cohorts; however, in later groups, the incidence rate decreased in the earlier stages of the exposure periods. The latent interval for the development of VWF was 6.4 +/- 3.7 years (6,000 to 7,000 hours) on average, with a 90% range of one to 14 years (700 to 16,000 hours). Of 452 study subjects with VWF (prevalence rate, 33.5%), 13.5% recovered within the exposure periods, 12.2% recovered within one year after the cessation of exposure, and 74.3% still had VWF more than two years after exposure had ended.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

[Clinical picture of vibration disease caused by an overall low-frequency jerky vibration and problems involved in sanatorium treatment].

On the basis of complex clinico-physiological examinations of 102 patients suffering from vibration disease caused by general low-frequency push-type vibration the following leading symptomocomplexes were determined: vegetative polyneuritis (53%), peripheral polyneuritis (20.5%), cerebral polyneuritis (13.7%), angiodystonic syndromes and lumbosacral radiculitis (12.7%). The patients were treated with two balneopelotherapeutic complexes, such as nitrogen thermal and bromoiodine baths plus mud applications. The dynamics of the disease symptoms and of the results of additional instrumental examinations has demonstrated the efficacy of the balneopelotherapy given in sanatorium conditions, this efficacy being dependent on the disease stage, prevailing syndrome, and the therapeutic complex used.

Adult↗
PubMed1996

[Prognostic assessment and risk of the development of vibration disease due to the effects of general vibration].

The studies revealed that evaluation of actual health disorders in people exposed to vibration requires up-to-date methodology, elaboration of new criteria that justify prophylactic measures. Taking into account a concept of occupational risk, scientists should have new approaches to hygienic regulation of general vibration in connection with load, levels, direction, quota of low-frequency components in total spectrum of mechanical oscillations.

Adult↗
PubMed2002

Vibrational analysis of substituted phenols: part I. Vibrational spectra, normal coordinate analysis and transferability of force constants of some formyl-, methoxy-, formylmethoxy-, methyl- and halogeno-phenols.

The Raman (including FT-Raman) and Fourier transform infrared (FTIR) spectra of 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 2-hydroxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 1,2-dihydroxy-3-methoxybenzene, 2,5-dihydroxytoluene, 2,6-dihydroxytoluene, pentachlorophenol and pentabromophenol were measured. Raman polarisation measurements were made wherever possible. A normal coordinate treatment was carried out for both the in-plane and out-of-plane vibrations of these molecules using a 123-parameter-modified valence force field. An overlay least-squares technique was employed to refine the force constants using 347 frequencies of 10 molecules. The reliability of these force constants was tested by making a zero-order calculation for 10 related molecules. Unambiguous vibrational assignments of all the fundamentals were made using the potential energy distributions and eigenvectors.

Fourier Analysis↗
PubMed2004

Vibrational analysis of mononitro substituted benzamides, benzaldehydes and toluenes. Part I. Vibrational spectra, normal coordinate analysis and transferability of force constants of nitrobenzamides, nitrobenzaldehydes and nitrotoluenes.

The Raman and Fourier transform infrared (FTIR) spectra of p-, m- and o-nitrobenzamides, p-, m- and o-nitrobenzaldehydes and p-, m- and o-nitrotoluenes were recorded. Raman polarisation measurements were made for the liquid samples. A normal coordinate analysis was carried out for both in-plane and out-of-plane vibrations of these molecules using 111-parameter modified valence force field. The force constants were refined using 316 frequencies of nine molecules in an overlay least-square technique. The reliability of the force constants was tested by making a zero-order calculation for nine related molecules. Unambiguous vibrational assignments of all the fundamentals were made by using the potential energy distributions and eigen vectors.

Benzaldehydes↗
PubMed2000

Metal-metal and metal-ligand vibrational interaction in compounds of the Fe3EE'(CO)9 (E, E' = S, Se, Te) series and the low-frequency vibrational spectra of Co2FeS(CO)9 and Os3S2(CO)9.

The infrared and Raman spectra of the title compounds in the ca. 400-150 cm-1 region are reported. For the first time, detailed assignments are given for all of the features in this region for the first series of compounds. An attempt is made to extend to all of the modes the plastic cluster model of vibrational analysis, which is normally applied only to nu(M-M) vibrations. While mixing occurs between nu(Fe-Fe) and nu(Fe-E), species containing Te posed particular problems; the reasons for this are discussed and give new insights into the plastic cluster model itself.

Journal Article↗
PubMed2006

Terahertz vibration-rotation-tunneling spectroscopy of the ammonia dimer: characterization of an out of plane vibration.

The terahertz vibration-rotation-tunneling (VRT) spectrum of the ammonia dimer (NH(3))(2) has been measured between ca. 78.5 and 91.9 cm(-1). The dipole-allowed transitions are separated into three groups that correspond to the 3-fold internal rotation of the NH(3) subunits. Transitions have been assigned for VRT states of the A-A (ortho-ortho) combinations of NH(3) monomer states. The spectrum is further complicated by strong Coriolis interactions. K = 0 <-- 0, K = 1 <-- 0, K = 0 <-- 1, and K = 1 <-- 1 progressions have been assigned. The band origins, rotational constants, asymmetry doubling, centrifugal distortion, and Coriolis coupling constant have been determined from the fit to an effective Hamiltonian. These VRT transitions are tentatively assigned to an out of plane vibration with a K = 0 state at 89.141305(47) cm(-1), and a K = 1 state at 86.77785(9) cm(-1).

Journal Article↗