400 research outputs found

    Contraversive neglect? A modulation of visuospatial neglect in association with contraversive pushing

    Get PDF
    Objective: Contraversive pushing (CP) is a neurologic disorder characterized by a lateral postural imbalance. Pusher patients actively push toward their contralesional side due to a misperception of the body's orientation in relation to gravity. Although not every patient with CP suffers from spatial neglect (SN), both phenomena are highly correlated in right-hemispheric patients. The present study investigates whether peripersonal visuospatial functioning differs in neglect patients with versus without CP (NP+ vs. NP+ patients). Method: Eighteen right-hemispheric stroke patients with SN were included, of which 17 in a double-blind case-control study and 1 single case with posterior pushing to supplement the discourse. A computer-based visuospatial navigation task, in which lateralized deviation can freely emerge, was used to quantify visuospatial behavior. In addition, visuospatial orienting was monitored using line bisection. Results: Significant intergroup differences were found. The NP+ patients demonstrated a smaller ipsilesional navigational deviation and more cross-over (contralesional instead of ipsilesional deviation) in long line bisection. As such, they demonstrated a contraversive (contralesionally directed) shift in comparison with the NP+ patients. Conclusions: These findings highlight the similarity between 2 systems of space representation. They are consistent with a coherence between the neural processing system that mainly provides for postural control, and the one responsible for nonpredominantly postural, visuospatial behavior

    Arthroscopic repair of subscapularis tear: Surgical technique and results

    Get PDF
    SummaryIntroductionArthroscopic management of extensive subscapularis tendon lesions was reported more recently than for the supra- and infra-spinatus tendons. Extensive tears create technical problems requiring an extra-articular approach. The few results so far reported have been encouraging.Study designSurgical techniques adapted to each type of tear according to our subscapularis lesion classification are described, with the preliminary results from our cohort.Patients and methodsBetween January 2006 and December 2008, 74 patients were operated on for extensive subscapularis tear. Twenty-three were assessed over a minimum 2 years’ follow-up (mean, 32 months) on UCLA, ASES and Constant scores, comparative dynamometric Bear-Hug test, visual analog pain scale and self-assessed shoulder function.ResultsPostoperative clinical results for the 23 patients followed up showed an improvement in shoulder function from 58 to 86%, in UCLA score from 16.4 to 30.9 points and in weighted Constant score from 48.6 to 75.2%.DiscussionIn case of severe tear, we recommend visualizing the subscapularis tendon along its main axis from above, on a lateral approach allowing the intra- and extra-articular parts to be controlled, so as to check the reduction achieved by traction wire and anatomic fixation by anchors and sutures via an anterior access of varying height but systematically kept under tension. Biceps tenodesis is often required. Results show a clear improvement on all scores: pain, strength and function. The failure rate was 9% (two cases). There were no complications.Level of evidenceIV (retrospective study)

    Field-effect control of superconductivity and Rashba spin-orbit coupling in top-gated LaAlO3/SrTiO3 devices

    Full text link
    The recent development in the fabrication of artificial oxide heterostructures opens new avenues in the field of quantum materials by enabling the manipulation of the charge, spin and orbital degrees of freedom. In this context, the discovery of two-dimensional electron gases (2-DEGs) at LAlO3/SrTiO3 interfaces, which exhibit both superconductivity and strong Rashba spin-orbit coupling (SOC), represents a major breakthrough. Here, we report on the realisation of a field-effect LaAlO3/SrTiO3 device, whose physical properties, including superconductivity and SOC, can be tuned over a wide range by a top-gate voltage. We derive a phase diagram, which emphasises a field-effect-induced superconductor-to-insulator quantum phase transition. Magneto-transport measurements indicate that the Rashba coupling constant increases linearly with electrostatic doping. Our results pave the way for the realisation of mesoscopic devices, where these two properties can be manipulated on a local scale by means of top-gates

    Prompt Alpha Decay of a Well-deformed Band in 58Ni

    Get PDF
    Two excited well-deformed bands have been observed in the semi-magic nucleus Ni-58. One of the bands was observed to partially decay by emission of a prompt discrete alpha particle that feeds the 2949 keV 6(+) spherical yrast state in the daughter nucleus Fe-54. This constitutes the first observation of prompt alpha emission from states lying in the deformed secondary minimum of the nuclear potential. gamma -ray linking transitions via several parallel paths establish the spin. parity, and excitation energy of this deformed band in Ni-58

    Temporal resolution deficits in the visual fields of MS patients

    Get PDF
    AbstractWe assessed the relationship between temporal resolution and MS-induced neuropathy. A diagnostic strategy comprising assessments of temporal resolution at 16 points in the extra-foveal visual field up to 12° from the fovea was first compared with foveal temporal resolution and with a standard VEP procedure in the same MS patients. At the group level, foveal temporal resolution was less sensitive to demyelination than the 16-point diagnostic strategy, the detection rate of which was comparable to that of the VEP procedure. Cross-sensitivity of the VEP and the 16-point diagnostic procedure was low. Subsequently, the average severity of MS-induced temporal resolution deficits was studied at three retinal loci of the same size but different eccentricities. Foveal deficits were not significantly greater than more peripheral deficits within the central 12°

    LO-phonon assisted polariton lasing in a ZnO based microcavity

    Full text link
    Polariton relaxation mechanisms are analysed experimentally and theoretically in a ZnO-based polariton laser. A minimum lasing threshold is obtained when the energy difference between the exciton reservoir and the bottom of the lower polariton branch is resonant with the LO phonon energy. Tuning off this resonance increases the threshold, and exciton-exciton scattering processes become involved in the polariton relaxation. These observations are qualitatively reproduced by simulations based on the numerical solution of the semi-classical Boltzmann equations

    Prompt Alpha Decay of a Well-deformed Band in 58Ni

    Get PDF
    Two excited well-deformed bands have been observed in the semi-magic nucleus Ni-58. One of the bands was observed to partially decay by emission of a prompt discrete alpha particle that feeds the 2949 keV 6(+) spherical yrast state in the daughter nucleus Fe-54. This constitutes the first observation of prompt alpha emission from states lying in the deformed secondary minimum of the nuclear potential. gamma -ray linking transitions via several parallel paths establish the spin. parity, and excitation energy of this deformed band in Ni-58

    Patterned silicon substrates: a common platform for room temperature GaN and ZnO polariton lasers

    Full text link
    A new platform for fabricating polariton lasers operating at room temperature is introduced: nitride-based distributed Bragg reflectors epitaxially grown on patterned silicon substrates. The patterning allows for an enhanced strain relaxation thereby enabling to stack a large number of crack-free AlN/AlGaN pairs and achieve cavity quality factors of several thousands with a large spatial homogeneity. GaN and ZnO active regions are epitaxially grown thereon and the cavities are completed with top dielectric Bragg reflectors. The two structures display strong-coupling and polariton lasing at room temperature and constitute an intermediate step in the way towards integrated polariton devices
    corecore