Risk factors for neck pain among forklift truck operators: a retrospective cohort study.

BACKGROUND: No previous research has been performed into neck pain among forklift operators. This is a common complaint among these workers, who number around 150,000 in Sweden and six million in Europe. The aim of the study was to examine long-term exposure to unnatural neck positions among forklift operators as a risk factor for neck pain. METHODS: A retrospective cohort study was conducted of all eligible employees at a high-level warehouse. Forklift operators and office workers answered an 18-page questionnaire comprising questions about joint pain, work tasks, work postures and year of start for all items. By using person years in the exposed and less-exposed groups before start of neck pain we were able to calculate Incident Rate ratios for various exposures. RESULTS: Forty nine percent of the forklift operators reported having experienced neck pain compared to 30 % of office workers. Being a forklift operator was associated with an increased risk of neck pain (OR = 5.1, 95% CI 1.4-18.2). Holding the head in an unnatural position resulted in significantly increased risks for neck pain, irrespective of type of position. The risks for neck pain remained after taking other ergonomic exposures and psychosocial aspects into consideration. CONCLUSIONS: This is the first published study showing that forklift operators have an increased risk of neck pain. The results are therefore of significance for improving work schedules, the adjustment of work tasks for these workers and the design of the vehicles.

Automatic fitting procedures for EPR spectra of disordered systems: matrix diagonalization and perturbation methods applied to fluorocarbon radicals.

Two types of automatic fitting procedures for EPR spectra of disordered systems have been developed, one based on matrix diagonalization of a general spin Hamiltonian, the other on 2nd order perturbation theory. The first program is based on a previous Fortran code complemented with a newly written interface in Java to provide user-friendly in and output. The second is intended for the special case of free radicals with several relatively weakly interacting nuclei, in which case the general method becomes slow. A least squares' fitting procedure utilizing analytical or numerical derivatives of the theoretically calculated spectrum with respect to the g- and hyperfine structure (hfs) tensors was used to refine those parameters in both cases. 'Rigid limit' ESR spectra from radicals in organic matrices and in polymers, previously studied experimentally at low temperature, were analyzed by both methods. Fluorocarbon anion radicals could be simulated, quite accurately with the exact method, whereas automatic fitting on, e.g. the c-C(4)F(8)(-) anion radical is only feasible with the 2nd order approximative treatment. Initial values for the (19)F hfs tensors estimated by DFT calculations were quite close to the final. For neutral radicals of the type XCF(2)CF(2)* the refinement of the hfs tensors by the exact method worked better than the approximate. The reasons are discussed. The ability of the fitting procedures to recover the correct magnetic parameters of disordered systems was investigated by fittings to synthetic spectra with known hfs tensors. The exact and the approximate methods are concluded to be complementary, one being general, but limited to relatively small systems, the other being a special treatment, suited for S=1/2 systems with several moderately large hfs.

Reduced pain after surgery for cervical disc protrusion/stenosis: a 2 year clinical follow-up.

PURPOSE: To follow the clinical outcome after surgery for cervical radiculopathy caused by degenerative cervical disc disease and to compare it with the outcome after conservative treatment. METHOD: Forty-three patients all awaiting surgery were studied prospectively. A control group of 39 conservatively treated patients were chosen, matched for gender and age. All patients rated their Sickness Impact Profile (SIP) and pain (VAS) and were clinically examined by unbiased observers initially and after 3, 9 and 24 months. RESULTS: Long-lasting pain reduction was noted both in the neck and in the arm for the operated patients, as well as improved sensory function and reduction of reflex disturbances. Their SIP showed a temporary improvement in the overall index, in the psychosocial dimension, in sleep/rest and home management, but only mobility remained improved. Among the operated patients referred directly to us, there was an improvement in SIP at the final follow-up. The control group's SIP indicated only a temporary improvement in sleep/rest. CONCLUSIONS: Surgically treated patients experienced pain reduction which was partially maintained for at least 24 months. A sustained improvement in the health status measured by SIP was observed only among operated patients that were not referred via the social insurance offices.

Outcome of surgery for cervical radiculopathy evaluated by determination of trapezius muscle microcirculation and electromyography.

Surgery for cervical radiculopathy was evaluated in 27 patients after anterior Cloward procedure (19 patients) or posterior decompression (eight patients). In addition, we examined 10 conservatively treated patients. Each patient was studied prospectively with regards to the effects on microcirculation in the local trapezius muscle during a fatiguing series of stepwise increased contractions. The right and left muscles were simultaneously examined pre-operatively and postoperatively after 9 months using laser-Doppler flowmetry and simultaneous surface electromyography (EMG). Preoperatively, a reduced microcirculation was found in the most painful side compared with the opposite side. This is in accordance with earlier reports on patients with chronic neurogenic neck pain, who also show reduced muscle tension on EMG. Postoperatively, the muscle blood flow became increased, but only in patients operated on via a posterior approach. A tendency at increased EMG-amplitude and reduced mean power frequency of the EMG was noted. These EMG signs of muscle fatigue suggest increased ability to exhaust the trapezius muscle postoperatively. The observed postoperative changes were consistently more frequent in the less painful side. We conclude from these objective measurements showing only a tendency at increased microcirculation and muscle tension postoperatively, that the effect on the trapezius muscle is limited.

Psychiatric nurses' conceptions of how a group supervision programme in nursing care influences their professional competence: a 4-year follow-up study.

AIM: The aim of the study was to describe, after 4 years, psychiatric nurses' conceptions of how a 2-year group supervision programme within nursing care had influenced their professional competence. BACKGROUND: The intention of group supervision in nursing care is to understand nurses' experiences within real care settings and to structure these in a professional and personal context. METHODS: Ten psychiatric nurses participated in a 2-year group supervision programme. They were interviewed 4 years after the group supervision was ended. Data were analysed according to the phenomenographic method. FINDINGS: Six description categories emerged: a feeling of job satisfaction; gaining knowledge and competence; gaining a sense of security in nursing situations; a feeling of personal development; realizing the value of supervision; and a sense of professional solidarity. CONCLUSIONS: The findings of the 4-year follow-up showed that a group supervision programme in nursing care had lasting influences on the psychiatric nurses' professional competence in the form of a pronounced professional identity and an integrated nursing care perspective. Group supervision contributes to maintaining the strength and energy needed to carry on working, which makes continuing supervision necessary. IMPLICATIONS: An important research implication could be to investigate the type of knowledge that ought to be developed within group supervision in nursing care.

Methods for determining the accuracy of radiostereometric analysis (RSA).

The problem of determining the noise level in any measuring system remains urgent. Radiostereometric analysis (RSA) is a radiographic system of unique accuracy which has applications in areas where minute motions or no motion at all occurs. Examples are micromotion between endoprostheses and bone and in fracture healing. We have determined the accuracy of the RSA system as applied to a clinical series of spinal fusions, where the conditions for RSA were not optimal. Using the usual test-retest methodology on a phantom, we showed that its accuracy can be grossly overestimated in the individual case. We found considerable variations in the accuracy in the individual case, depending on the rigid-body configuration. The overall accuracy, expressed as 3-D "vectors" for rotation and translation, respectively, correlated with the condition number, a method for characterizing the marker configuration. Indeed, the condition number explained as much as 92% of the variation in overall rotation. This condition number, however, cannot be used to analyze the accuracy of one degree of freedom of rotation alone. Mathematical simulation of the accuracy in the individual case of the individual dimension, using in-house software, showed that the accuracy (95% confidence) varied between 0.4 and 4.6 degrees of rotation about the transverse axis, corresponding to a clinical stress series of extension and flexion.

Rigid fusion after cloward operation for cervical disc disease using autograft, allograft, or xenograft: a randomized study with radiostereometric and clinical follow-up assessment.

STUDY DESIGN: In this study, 43 patients scheduled for a single-level cervical Cloward procedure for disc disease were randomized prospectively to fusion with autograft, allograft, or xenograft. OBJECTIVE: To outline any differences in fusion over time in terms of final mobility and clinical outcome between the three bone grafts. SUMMARY OF BACKGROUND DATA: Fusion is used to relieve pain from a spinal segment. The bovine xenograft gives a fibrous fusion in contrast to the solid bone fusion obtained with autograft from the iliac crest, but no definite differences in clinical outcome have been shown previously after surgery at a single level. METHODS: By use of radiostereometric analysis, 33 patients were observed after 6, 12, and 24 to 50 (mean, 37) months. All 43 patients underwent clinical examination, which involved pain rating before and after surgery, with a final follow-up assessment by an unbiased observer. RESULTS: Mobility could be demonstrated in 9 patients after 1 year and in 6 patients at the final follow-up assessment, without pain, and with no difference between bone grafts. The patients who received autograft experienced a greater reduction of pain than the patients treated with xenograft. CONCLUSIONS: Most of the patients healed with a rigid fusion no matter which graft was used, but the healing process took longer than expected. The clinical results were not influenced by whether mobility could be demonstrated. There was a tendency toward better clinical results in the patients treated with autograft.

The Pharmaceutical Benefits Scheme and the shifting paradigm of welfare policy.

This paper describes the design and operation of the Pharmaceutical Benefits Scheme and then proceeds with an analysis of current policy deliberations which identifies an extension of the market as predominant trend. The paper demonstrates that the conditions which historically sustained the scheme are now present to a lesser extent. The Pharmaceutical Benefits Scheme has functioned as a universalist welfare program which conferred onto the Commonwealth Department of Health substantial powers vis-à-vis drug suppliers and professional groups. This position of dominance has been eroded, with challenges to established arrangements arising, in particular, from the enhanced bargaining position of business and wider pressures operating on the Keynesian welfare state.

Sodium ion diffusion through liposome membranes containing cerebroside.

Na+ efflux from liposomes (small unilamellar vesicles, SUV) of various compositions was studied, using 22Na+ and 3H-labelled stachyose in simultaneous dual isotope measurements, stachyose being used as a measure of liposome disintegration. Dialysis was utilised to separate liposomes from extra-liposomal activity. Liposomes were made from egg lecithin and sphingomyelin and from mixtures of egg lecithin, sphingomyelin, cerebroside, sulphatide and cholesterol. All mixtures produced more leaky and less stable SUVs than pure lecithin and pure sphingomyelin. The incorporation of cerebroside is significantly smaller than that of the phospholipids including sphingomyelin. It was found that membranes containing cerebroside had a significantly higher Na+ permeability than membranes without cerebroside.

A new instrument for measuring surface pressure.

A new instrument for surface pressure measurements using a floating-foil technique has been constructed. The instrument makes use of a probe in the form of a thin foil suspended at the gas/liquid or liquid/liquid interface tension. The present instrument has a dynamic range of 0.1-70 mN/m and a sensitivity better than 0.1 mN/m. Its speed of response is 50 ms but much faster measurements are possible. Measurements on behenic acid and cholesterol films on water and on a cerebroside film at a heptane/water interface are presented.

Accommodation of hydroxyl groups and their hydrogen bond system in a hydrocarbon matrix.

From data of a single crystal analysis of 12-D-hydroxyoctadecanoic acid methyl ester principles for the incorporation of hydroxyl groups into a hydrocarbon chain matrix can be deduced. In the crystalline compound infinite hydrogen bond systems are accommodated in an orthorhombic perpendicular chain arrangement. The orthorhombic perpendicular hydrocarbon subcell is expanded towards a hexagonal packing pattern, allowing more space and optimal geometry for the hydrogen bond system. The arrangement of the bond system in the orthorhombic perpendicular subcell requires that hydrogen bonded carbon chains carry alternatingly hydroxyl groups with opposite configuration. For the enantiomeric compound this requirement is met by a head to tail packing of molecules in a single layer arrangement. The corresponding racemates on the other hand pack head to head in double layers as confirmed by X-ray powder and IR studies. In monolayers both enantiomers and racemates behave identically. The hydrogen bonding of the hydroxyl groups apparently leads to the formation of lipid clusters, in which the geometric conditions for both a close packing of hydrocarbon chains and the formation of an extensive hydrogen bond system do not exist.

Molecular arrangements of sphingolipids. The monolayer behaviour of ceramides.

A series of synthetic ceramides have been studied at the air-water interface by recording the surface pressue-area isotherms at continuous compression. Ceramides that contain a 4,5-trans-double bond in the long chain base were found to condense into a close-packed arrangement with vertical chains already at a very low surface pressure. The corresponding saturated compounds adopt a similar close packed arrangement only at high surface pressue. At 30 dynes/cm, a lateral pressure representative of biological membranes, the area per molecule and compressibility was further found to depend on the number and configuration of the hydroxyl groups. The presence of a 2-D-hydroxyl group in the fatty acid generally promotes the condensation. A similar effect is observed if the long chain base contains a 4-D-hydroxyl group. Cis-double bonds or methyl branches in the fatty acid chain, which increase the space requirement, limit the lateral interaction of the polar group. However the 15-cis-double bond of nervonic acid can be accomodated without any distortion of the close-packing arrangement.

Surface balance study of the interaction between microorganisms and lipid monolayer at the air/water interface.

Using the surface balance technique, we have compared the interaction between Acholeplasma laidlawii and some marine bacteria towards different types of monolayered lipid films. Cells from A. laidlawii and Serratia marinorubra penetrate the film, whereas cells from Psuedomonas fluorescens form a layer underneath the film. The forces that bind microorganisms to the air/water interface are not strong enough to scatter a condensed monolayer but increase the strength of loosely packed monolayers.