431 research outputs found
Common universal behavior of magnetic domain walls driven by spin-polarized electrical current and magnetic field
We explore the universal behaviors of a magnetic domain wall driven by the spin-transfer torque of an electrical current, in a ferromagnetic (Ga,Mn)(As,P) thin film with perpendicular magnetic anisotropy. For a current transverse to the domain wall, the dynamics of the thermally activated creep regime and the depinning transition are found to be compatible with a self-consistent universal description of magnetic-field-induced domain-wall dynamics. This common universal behavior, characteristic of the so-called quenched Edwards-Wilkinson universality class, is confirmed by an independent analysis of domain-wall roughness. Complementary investigations reveal the directional properties of interaction between current and domain walls which result in the instability of their transverse orientation.Fil: Diaz Pardo, R.. Centre National de la Recherche Scientifique; Francia. Université Paris Sud; FranciaFil: Moisan, N.. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; FranciaFil: Albornoz, Lucas Javier. Université Paris Sud; Francia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Lemaßtre, A.. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; FranciaFil: Curiale, Carlos Javier. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Bariloche.; ArgentinaFil: Jeudy, V.. Centre National de la Recherche Scientifique; Francia. Université Paris Sud; Franci
Lower limb biomechanics during drop jump landing in individuals with chronic ankle instability
ABSTRACT
Context: Individuals with chronic ankle instability (CAI) exhibit impaired lower limb biomechanics during unilateral drop jump landing on a flat surface. However, lower limb biomechanical adaptations during unilateral drop jump landing on more challenging surfaces such as unstable or inclined are yet to be described.
Objective: Determine how unilateral drop jump landing surfaces (flat, unstable and inclined) influence lower limb EMG, kinematics and kinetics in individuals with CAI.
Design: Descriptive laboratory study.
Setting: Biomechanics laboratory.
Patients or Other Participants: Twenty-two young adults with CAI
Interventions: Participants completed five trials of unilateral drop jump landing from a 46 cm height platform on flat (DROP), unstable (FOAM) and laterally inclined (WEDGE) surfaces.
Main outcome measure(s): EMG of gluteus medius, vastus lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior muscles were recorded. Knee and ankle angles and moments were calculated using a three-dimensional motion analysis system and a force plate. Biomechanical variables were compared between tasks using one-dimensional statistical nonparametric mapping.
Results: During DROP, greater ankle dorsiflexion angles, knee extension moments and vastus lateralis muscle activity (FOAM only) were observed compared to FOAM and WEDGE. Greater ankle inversion angles were observed during FOAM and WEDGE compared to DROP. Peroneus longus muscle activity was greater during DROP compared to FOAM. During FOAM, greater ankle inversion and knee extension angles, ankle inversion and internal rotation moments as well as smaller peroneus longus muscle activity were observed compared to WEDGE.
Conclusions: The greater ankle inversion and plantarflexion angles as well as the lack of increase in peroneus longus muscle activation during FOAM and WEDGE could increase the risk of recurrent LAS in individuals with CAI. The results of this study improve our understanding of lower limb biomechanics changes when landing on more challenging surfaces and will help clinicians better targeting deficits associated with CAI during rehabilitation
Lower limb biomechanics in individuals with chronic ankle instability during gait: a case-control study
Individuals with chronic ankle instability (CAI) exhibit many biomechanical changes to lower limbs during walking. However, only a few studies have investigated the differences in lower limb biomechanics of individuals with CAI compared to healthy controls using a comprehensive approach including kinematic, kinetic and electromyography (EMG) measures. Consequently, the theoretical framework explaining the biomechanical adaptations in individuals with CAI is mostly based on the results of studies including heterogenous methods and participantsâ specificities (e.g., level of disability). More studies using a comprehensive approach are needed to better understand the biomechanical adaptations associated with CAI. The objective of this case-control study was to identify the kinematic, kinetic and EMG differences between individuals with CAI and healthy controls during walking
PrĂ©venir les troubles musculosquelettiques chez les soignants : connaĂźtre les expositions et Ă©tude des outils dâaide Ă la manutention
ObjectifsDans le cadre de la Caisse nationale de retaite des agents des collectivitĂ©s locales (CNRACL), la dĂ©marche dâĂ©valuation et de prĂ©vention des risques vise Ă conduire Ă une dĂ©marche spĂ©cifique au milieu hospitalier et Ă construire des outils dâĂ©valuation des risques dans le rĂ©seau des CHU français. Les Ă©tudes menĂ©es sur la prĂ©vention des troubles musculosquelettiques (TMS) associent principalement les compĂ©tences en ergonomie, Ă©pidĂ©miologie et mĂ©decine du travail des CHU dâAngers et de Grenoble. MĂ©thode Une premiĂšre Ă©tude Ă©pidĂ©miologique a permis dâidentifier les facteurs de risque de TMS et de lombalgie en milieu hospitalier ; une seconde sâest intĂ©ressĂ©e Ă lâĂ©valuation des outils dâaide Ă la manutention des patients en milieu de soins sous un angle ergonomique. RĂ©sultats Les salariĂ©s du secteur santĂ© sont en moyenne exposĂ©s Ă 2,4 facteurs de risque des 19 rĂ©pertoriĂ©s (3,5 pour le reste du rĂ©seau) et ne souffrent pas plus de TMS des membres supĂ©rieurs que les autres salariĂ©s de la rĂ©gion des Pays-de-la-Loire. En revanche, les expositions aux manutentions manuelles de charges lourdes liĂ©es aux soins aux patients sont plus frĂ©quentes. Les aides techniques pour la manutention Ă©tudiĂ©es ne rĂ©pondent pas aux critĂšres de dĂ©pendance du patient ou aux conditions organisationnelles du service. Du point de vue psychologique, le rapport du patient au matĂ©riel ainsi que lâusage du corps du soignant dans la relation aux soins doivent ĂȘtre pris en compte. Conclusion Lâapproche biomĂ©canique a fait lâobjet de cette premiĂšre investigation. Il sâagit dâune dĂ©marche de prĂ©vention pluridisciplinaire intĂ©grĂ©e dans la politique dâĂ©tablissement
The effect of introducing IGRA to screen French healthcare workers for tuberculosis and potential conclusions for the work organisation
INTRODUCTION: In France, pre-employment screening for tuberculosis (TB) is performed for healthcare workers (HCW). Screening is repeated when exposure to TB patients or infectious material occurs. The results of these TB screenings were analysed in a retrospective analysis.
METHOD: Tuberculin skin tests (TST) and interferon-gamma release assays (QuantiFERONÂź Gold In-Tube - QFT) were used to perform the TB screenings. The screening results of 637 HCWs on whom QFT was performed were taken from the records of the University Hospital of Nantes.
RESULTS: In three (0.5%) HCW, the QFT was indeterminate. In 22.2%, the QFT was positive. A second QFT was performed in 118 HCWs. The reversion rate was 42% (5 out of 17). The conversion rate was 6% (6 out of 98). A TST was performed on 466 (73.5%) of the HCWs. Results for TSTâ>â10Â mm were 77.4%. In those with a TSTâ<â10Â mm, QFT was positive in 14% and in those with a TSTââ„â10Â mm, QFT was positive in 26.7%. Depending on the definition for conversion in the QFT, the annual attack rate was 4.1% or 7.3%. X-ray and pneumology consultation was based on positive QFT rather than TST alone (52 out of 56). No active TB was detected.
CONCLUSION: The TST overestimated the prevalence of LTBI in this cohort. The decision about X-ray and consultation regarding preventive treatment should be based on the QFT rather than the TST results. The high reversion rate should be taken into consideration when consulting with HCWs regarding preventive treatment. The high conversion rate seems to indicate that preventive measures such as wearing masks should be improved
Neutron to proton ratios of quasiprojectile and midrapidity emission in the Zn + Zn reaction at 45 MeV/nucleon
Simultaneous measurement of both neutrons and charged particles emitted in
the reaction Zn + Zn at 45 MeV/nucleon allows comparison of the
neutron to proton ratio at midrapidity with that at projectile rapidity. The
evolution of N/Z in both rapidity regimes with increasing centrality is
examined. For the completely re-constructed midrapidity material one finds that
the neutron-to-proton ratio is above that of the overall Zn + Zn
system. In contrast, the re-constructed ratio for the quasiprojectile is below
that of the overall system. This difference provides the most complete evidence
to date of neutron enrichment of midrapidity nuclear matter at the expense of
the quasiprojectile
Influence of Neutron Enrichment on Disintegration Modes of Compound Nuclei
Cross sections, kinetic energy and angular distributions of fragments with
charge 6Z28 emitted in 78,82Kr+40C at 5.5 MeV/A reactions were
measured at the GANIL facility using the INDRA apparatus. This experiment aims
to investigate the influence of the neutron enrichment on the decay mechanism
of excited nuclei. Data are discussed in comparison with predictions of
transition state and Hauser-Feshbach models.Comment: 8 pages, 1 figure, paper presented at the First Workshop on "State of
the Art in Nuclear Cluster Physics" 13-16 May, 2008, at Strasbourg, France
(SOTANCP2008) and accepted for publication at International Journal of Modern
Physics E (Special Issue), Proceedings of SOTANCP2008 (to be published
Analyse génétique comparée de 19 formes recombinantes VIH-1 inter-groupes M et O et impact évolutif
International audienc
PLoS One
BACKGROUND: In Cote d'Ivoire, people living with HIV (PLHIV) have free access to antiretroviral therapy (ART) and cotrimoxazole. Yet, they may use other medications to treat non-HIV diseases. Scarce data are available regarding the use of non-HIV medications in Africa. This study describes the use of non-HIV medications and identifies the factors associated with their use by PLHIV on ART in Cote d'Ivoire. METHODS: A cross-sectional study was conducted in six HIV clinics in 2016. HIV-1-infected adults receiving ART for at least one year were eligible. A standardized questionnaire was used to collect demographics, HIV characteristics and medication use data. Associated factors were identified using a multivariate adjusted Poisson regression. RESULTS: A total of 1,458 participants (74% women) were enrolled. The median age was 44 years, and the median duration of ART was 81 months. A total of 696 (48%) participants reported having used at least one non-HIV medication. Among the 1,519 non-HIV medications used, 550 (36%) had not been prescribed and 397 (26%) were from the nervous system class. Individuals who were more likely to report the use of at least one non-HIV medication included those who had been treated in an Abidjan HIV clinic, had a high school education level, had a monthly income between 152 and 304 euros, had a poor perceived health status, had WHO advanced clinical stage, had used traditional medicine products and had not used cotrimoxazole. CONCLUSION: Almost half PLHIV on ART reported using non-HIV medication. Further research is needed to assess whether the use of non-HIV medication is appropriate given about a third of those medications are not being prescribed
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