Chronic low back pain, chronic disability at work, chronic management issues.

Low-back  pain  (LBP)  stands  out  as  the  leading  musculoskeletal  disorder  because  it  is  both  highly prevalent and the disability with which people live for the greatest number of years (1, 2). Reaching a peak between the ages of 30–50 years, LBP affects a population at a time of career advancement (3, 4). Back pain is the most expensive disease in terms of indirect costs due to sickness absence and work disability. Indirect (or productivity) costs contribute 93% to total costs, illustrating the importance of the consequences of the disease for work performance (5, 6). On a personal level, low self-motivation and self-confidence make it harder to initiate the return-to-work (RTW) process, especially when problems at work are related to the reason for sick leave (7, 8). At the workplace level, colleagues take over the tasks of the worker on sick leave, work piles up, or another worker is hired to take over the tasks. Timely RTW is thus of great benefit for both injured workers and their employers. [...

Prévalence des lombalgies et de leurs facteurs de risque professionnels chez les travailleurs de l'agriculture en France en 2010

Introduction La phase pilote du programme Coset-MSA a permis d’évaluer la prévalence des lombalgies et de leurs facteurs de risque professionnels chez les travailleurs de l’agriculture, et notamment les agriculteurs exploitants et les ouvriers agricoles. Méthodes Les travailleurs ont été recrutés, dans cinq départements, par tirage au sort dans les bases de données de la MSA et invités à remplir un auto-questionnaire portant sur les expositions et les lombalgies au cours des 12 derniers mois. L’échantillon d’analyse était constitué de 1130 travailleurs, âgés de 18 à 65 ans, exerçant dans le secteur agriculture, sylviculture et pêche, et en activité au moment de l’enquête. Résultats La prévalence des lombalgies au cours des 12 derniers mois était élevée, chez les hommes (65 %) comme chez les femmes (64 %). Chez ces dernières, la prévalence diminuait significativement avec l’âge (de 95 % chez les moins de 30 ans à 56 % chez les 50 ans et plus, p < 0,01). Des douleurs quotidiennes étaient rapportées par 10 % des hommes et 11 % des femmes, avec une prévalence qui augmentait avec l’âge, de façon significative chez les hommes (p < 0,001). La prévalence ne différait pas significativement selon la catégorie socioprofessionnelle (CSP). Cependant, soulignons la forte prévalence des lombalgies parmi les hommes artisans, commerçants et chefs d’entreprise (surtout des jardiniers, paysagistes…) malgré des effectifs faibles. Chez les femmes, les agricultrices exploitantes et les ouvrières agricoles étaient plus nombreuses à souffrir de lombalgies, quelle que soit la durée des symptômes. Le port de charges de plus de 25 kg plus de 2 heures par jour concernait 16 % des hommes et 5 % des femmes, se pencher en avant ou sur le côté plus de 4 heures par jour 15 % et 16 % respectivement et la conduite plus de 4 heures par jour 27 % et 10 %. Chez les hommes, les ouvriers non agricoles étaient les plus exposés aux trois facteurs (17 % au port de charges [p < 0,05], 22 % au fait de se pencher [p < 0,01], 32 % à la conduite [NS]). Chez les femmes, les ouvrières agricoles rapportaient les plus fortes expositions : 29 % se penchaient plus de 4 h/j (p < 0,001) et 16 % conduisaient plus de 4 h/j (NS). Conclusions La prévalence des lombalgies est particulièrement élevée dans l’agriculture, comparativement à des études portant sur tous secteurs d’activité (par exemple, l’étude Cosali menée auprès de salariés des Pays de la Loire). De plus, cette étude permet d’identifier les CSP les plus exposées aux facteurs de risque professionnels de lombalgie, qui devraient être ciblées prioritairement par les actions de prévention

Excitation of surface plasmon-polaritons in metal films with double periodic modulation: anomalous optical effects

We perform a thorough theoretical analysis of resonance effects when an arbitrarily polarized plane monochromatic wave is incident onto a double periodically modulated metal film sandwiched by two different transparent media. The proposed theory offers a generalization of the theory that had been build in our recent papers for the simplest case of one-dimensional structures to two-dimensional ones. A special emphasis is placed on the films with the modulation caused by cylindrical inclusions, hence, the results obtained are applicable to the films used in the experiments. We discuss a spectral composition of modulated films and highlight the principal role of ``resonance'' and ``coupling'' modulation harmonics. All the originating multiple resonances are examined in detail. The transformation coefficients corresponding to different diffraction orders are investigated in the vicinity of each resonance. We make a comparison between our theory and recent experiments concerning enhanced light transmittance and show the ways of increasing the efficiency of these phenomena. In the appendix we demonstrate a close analogy between ELT effect and peculiarities of a forced motion of two coupled classical oscillators.Comment: 24 pages, 17 figure

Topological phase transitions between chiral and helical spin textures in a lattice with spin-orbit coupling and a magnetic field

We consider the combined effects of large spin-orbit couplings and a perpendicular magnetic field in a 2D honeycomb fermionic lattice. This system provides an elegant setup to generate versatile spin textures propagating along the edge of a sample. The spin-orbit coupling is shown to induce topological phase transitions between a helical quantum spin Hall phase and a chiral spin-imbalanced quantum Hall state. Besides, we find that the spin orientation of a single topological edge state can be tuned by a Rashba spin-orbit coupling, opening an interesting route towards quantum spin manipulation. We discuss the possible realization of our results using cold atoms trapped in optical lattices, where large synthetic magnetic fields and spin-orbit couplings can be engineered and finely tuned. In particular, this system would lead to the observation of a time-reversal-symmetry-broken quantum spin Hall phase.Comment: 8 pages, 3 figures, Accepted in Europhys. Lett. (Dec 2011

Epidemiological surveillance of lumbar disc surgery in the general population: a pilot study in a French region.

OBJECTIVES: Disc-related sciatica (DRS) is a significant and costly health problem in the working population. The aim of this pilot study was to assess the feasibility of a surveillance system for DRS using hospital databases for lumbar disc surgery (LDS). METHODS: A total of 272 inpatients (119 men and 153 women) living in a French region and discharged in 2002-2003 from a spine center of a large University Hospital following LDS were compared with demographic and socioeconomic data on the population of the same region. Medical and occupational histories were gathered using a mailed questionnaire. The age-adjusted relative risks and population attributable fraction of risk (PAF) were calculated in relation to occupations and industries. RESULTS: Information on employment was available for the 75 women and 71 men. The risk of LDS varied according to occupations and industries. PAFs ranged between 30% (12-48) for male blue collar workers and 22% (4-40) for female lower white collar workers. PAFs ranged between 7 and 17% in the economic sectors at high risk. CONCLUSION: The surveillance of LDS can identify occupations and industries at risk

Population attributable risk of lumbar disc surgery according to occupation: a study in a French general population

Aims: Disc-related sciatica represents one of the most significant and costly health problems occurring in the working population. The aim of this study was to assess the work-related population attributable fraction (PAF) of lumbar disc surgery (LDS) for disc-related sciatica in occupational categories at high risk in the general population. Methods: Patients living in a French region in 2003 and discharged from a large University Hospital following LDS were compared with demographic and socioeconomic data from the population census. Medical and occupational histories from 75 women and 71 men were gathered using a mailed questionnaire. The ageadjusted relative risks and PAF of CTS were calculated according to occupational categories. Results: The PAFs of lumbar disc surgery was 37% [19-54] for the male blue-collar workers suggesting that about 37% of the cases occurring in this category of workers could be avoided if the excess risk of LDS could be eliminated. The PAF value for male and female lower-grade white collar workers and female intermediate occupations were 18%, 33% and 13%, respectively. Conclusion: The study suggested that 13–37% of LDS for disc-related sciatica might be avoided in the whole population if totally effective intervention programs were implemented in specific occupational categories or industries. However, these preliminary findings must be confirmed by a larger study conducted in the whole region to assess more accurately the proportion of avoidable cases of LDS in the population

Biomechanical constraints remain major risk factors for low back pain. Results from a prospective cohort study in French male employees

BACKGROUND CONTEXT: Low back pain (LBP) is a major public health problem, with a considerable impact on workers. PURPOSE: To model the risk of LBP in the male general working population. STUDY DESIGN/SETTING: Repeated cross-sectional surveys in a wide occupational setting. PATIENT SAMPLE: A random sample of 2,161 men working in various occupations in a French region participated in a first survey in 2002, and 1,313 of these (60.8%) participated in a second survey in 2007. OUTCOME MEASURE: The self-reported prevalence of LBP during the previous week in the second survey. METHODS: Twenty-one biomechanical, organizational, psychosocial, and individual factors were assessed in the first survey. The association between these potential risk factors and the prevalence of later LBP (in the second survey) was studied, using multistep logistic regression models. RESULTS: Three hundred ninety-four men reported LBP in the second survey (prevalence 30.0%). The final multivariate model highlighted four risk factors: frequent bending (odds ratio [OR], 1.45, 95% confidence interval [CI], 1.07-1.97 for bending forward only; and OR, 2.13, 95% CI, 1.52-3.00 for bending both forward and sideways), driving industrial vehicles (OR, 1.35; 95% CI, 1.00-1.81), working more hours than officially planned (OR, 1.38; 95% CI, 1.05-1.81), and reported low support from supervisors (OR, 1.35; 95% CI, 1.02-1.79). CONCLUSIONS: These results emphasize that biomechanical factors remain worth considering, even when psychosocial factors are taken into account, and provide a significant contribution to preventive strategies

Engineering oxygen containing and amino groups into two dimensional atomically thin porous polymeric carbon nitrogen for enhanced photocatalytic hydrogen production

Oxygen-containing and amino groups functionalized polymeric carbon nitride atomically-thin porous nanosheets with hydrophilic surfaces and strong Lewis basicity are designed and synthesized for enhanced photocatalytic H2evolution.</p

Role of dynamic Jahn-Teller distortions in Na2C60 and Na2CsC60 studied by NMR

Through 13C NMR spin lattice relaxation (T1) measurements in cubic Na2C60, we detect a gap in its electronic excitations, similar to that observed in tetragonal A4C60. This establishes that Jahn-Teller distortions (JTD) and strong electronic correlations must be considered to understand the behaviour of even electron systems, regardless of the structure. Furthermore, in metallic Na2CsC60, a similar contribution to T1 is also detected for 13C and 133Cs NMR, implying the occurence of excitations typical of JT distorted C60^{2-} (or equivalently C60^{4-}). This supports the idea that dynamic JTD can induce attractive electronic interactions in odd electron systems.Comment: 3 figure

Dynamical Critical Phenomena in three-dimensional Heisenberg Spin Glasses

Spin-glass (SG) and chiral-glass (CG) orderings in three dimensional (3D) Heisenberg spin glass with and without magnetic anisotropy are studied by using large-scale off-equilibrium Monte Carlo simulations. A characteristic time of relaxation, which diverges at a transition temperature in the thermodynamic limit, is obtained as a function of the temperature and the system size. Based on the finite-size scaling analysis for the relaxation time, it is found that in the isotropic Heisenberg spin glass, the CG phase transition occurs at a finite temperature, while the SG transition occurs at a lower temperature, which is compatible with zero. Our results of the anisotropic case support the chirality scenario for the phase transitions in the 3D Heisenberg spin glasses.Comment: 9 pages, 19 figure