1,071 research outputs found

    A randomized clinical control study on the efficacy of three-dimensional upper limb robotic exoskeleton training in chronic stroke

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    Background : Although robotics assisted rehabilitation has proven to be effective in stroke rehabilitation, a limited functional improvements in Activities of Daily Life has been also observed after the administration of robotic training. To this aim in this study we compare the efficacy in terms of both clinical and functional outcomes of a robotic training performed with a multi-joint functional exoskeleton in goal-oriented exercises compared to a conventional physical therapy program, equally matched in terms of intensity and time. As a secondary goal of the study, it was assessed the capability of kinesiologic measurements—extracted by the exoskeleton robotic system—of predicting the rehabilitation outcomes using a set of robotic biomarkers collected at the baseline. Methods : A parallel-group randomized clinical trial was conducted within a group of 26 chronic post-stroke patients. Patients were randomly assigned to two groups receiving robotic or manual therapy. The primary outcome was the change in score on the upper extremity section of the Fugl-Meyer Assessment (FMA) scale. As secondary outcome a specifically designed bimanual functional scale, Bimanual Activity Test (BAT), was used for upper limb functional evaluation. Two robotic performance indices were extracted with the purpose of monitoring the recovery process and investigating the interrelationship between pre-treatment robotic biomarkers and post-treatment clinical improvement in the robotic group. Results : A significant clinical and functional improvements in both groups (p < 0.01) was reported. More in detail a significantly higher improvement of the robotic group was observed in the proximal portion of the FMA (p < 0.05) and in the reduction of time needed for accomplishing the tasks of the BAT (p < 0.01). The multilinear-regression analysis pointed out a significant correlation between robotic biomarkers at the baseline and change in FMA score (R2 = 0.91, p < 0.05), suggesting their potential ability of predicting clinical outcomes. Conclusion : Exoskeleton-based robotic upper limb treatment might lead to better functional outcomes, if compared to manual physical therapy. The extracted robotic performance could represent predictive indices of the recovery of the upper limb. These results are promising for their potential exploitation in implementing personalized robotic therapy. Clinical Trial Registration clinicaltrials.gov, NCT03319992 Unique Protocol ID: RH-UL-LEXOS-10. Registered 20.10.2017, https://clinicaltrials.gov/ct2/show/NCT0331999

    The three-body recombination of a condensed Bose gas near a Feshbach resonance

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    In this paper, we study the three-body recombination rate of a homogeneous dilute Bose gas with a Feshbach resonance at zero temperature. The ground state and excitations of this system are obtained. The three-body recombination in the ground state is due to the break-up of an atom pair in the quantum depletion and the formation of a molecule by an atom from the broken pair and an atom from the condensate. The rate of this process is in good agreement with the experiment on 23^{23}Na in a wide range of magnetic fields.Comment: 10 pages, 2 figures, to be published in Phys. Rev.

    Casimir-like tunneling-induced electronic forces

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    We study the quantum forces that act between two nearby conductors due to electronic tunneling. We derive an expression for these forces by calculating the flux of momentum arising from the overlap of evanescent electronic fields. Our result is written in terms of the electronic reflection amplitudes of the conductors and it has the same structure as Lifshitz's formula for the electromagnetically mediated Casimir forces. We evaluate the tunneling force between two semiinfinite conductors and between two thin films separated by an insulating gap. We discuss some applications of our results.Comment: 8 pages, 3 figs, submitted to Proc. of QFEXT'05, to be published in J. Phys.

    Sistemas de produção: conceitos e definições no contexto agrícola.

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    Introdução. Definições e exemplificações de sistemas: Sistema de cultivo, Sistema de produção, Sistema em monocultura ou produção isolada; Sistema em sucessão de culturas; Sistema em consorciação de culturas ou policultivo; Sistema em integração: lavoura-pecuária, lavoura-floresta, pecuária-floresta, lavoura-pecuária-floresta. Ausência de interação. Interação entre sistemas de cultivo/criação conduzidos em diferentes áreas físicas. Interação entre sistemas de cultivo/criação conduzidos em um mesmo espaço físico. Sistema agrícola: sistema de sucessão soja - milho/trigo em SPD na região de Londrina-PR; sistema de sucessão soja - milho/sorgo em SPD na região de Rio Verde-GO; sistema de rotação soja-trigo (ano 1); soja-aveia ou nabo forrageiro (ano 2); milho-nabo forrageiro-trigo (ano 3); e soja-aveia (ano 4), em SPD na região de Passo Fundo-RS. sistema de sucessão soja ? milho/algodão em SPD na região de Sapezal-MT; sistema de sucessão soja - girassol/sorgo em SPD na região de Campo Novo do Parecis-MT; sistema de integração arroz irrigado-azevém para pastejo, na região de Pelotas-RS. sistema de sucessão de cana-de-açúcar com cultivo de amendoim durante o período de reforma do canavial na região de Sertãozinho-SP. sistema de sucessão de cana-de-açúcar com cultivo de Crotalaria spectabilis durante o período de reforma do canavial na região de Coruripe-AL. Bioma. Considerações finais.bitstream/item/69333/1/Doc-335-OL.pd

    On the solar origin of the 200 y Suess wiggles: Evidence from thermoluminescence in sea sediments

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    In order to understand the origin of the Suess wiggles, present in the tree ring 14C record, we have studied the thermoluminescence (TL) of a shallow-water Ionian sea core, in an attempt to provide a record of an indicator responding to the solar output more promptly than 14C in tree rings. The spectral content of the TL and radiocarbon records is very similar; neverthless, in addition to the 207 y Suess wave (A43.6% ), the TL record shows the second harmonic (103.5 y; A42.4% ), in phase with the envelope of the 11 y solar cycles. This result, obtained by different spectral methods, in particular by Superposition of Epochs (SE) and by Singular Spectrum Analysis (SSA), strongly supports the solar origin of the 200 y Suess wiggles

    Ion channel-like activity of the antimicrobial peptide tritrpticin in planar lipid bilayers

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    The cationic peptide tritrpticin (VRRFPWWWPFLRR, Trp3) has a broad action spectrum, acting against Gram-positive and Gram-negative bacteria, as well as some fungi, while also displaying hemolytic activity. We have studied the behavior of Trp3 in planar lipid bilayers (or black lipid membrane-BLM) and were able to demonstrate its ion channel-like activity. Channel-like activity was observed in negatively charged azolectin BLM as a sudden appearance of discrete current fluctuations upon application of a constant voltage across the membrane. Trp3 formed large conductance channels (500-2000 pS) both at positive and negative potentials. in azolectin bilayers, the predominant ion-channel activity was characterized by very regular and discrete current steps (corresponding to openings) of uniform amplitude, which exhibited relatively long residence times (of the order of seconds). Occasionally, multiple conductance steps were observed, indicating the simultaneous presence of more than one open pore. in bilayers of zwitterionic diphytanoylphosphatidyl choline (DPhk) Trp3 also showed ion-channel activity, but in a much less frequent and less prominent way. Studies of ion selectivity indicated that Trp3 forms a cation-selective channel. These results should contribute to the understanding of the molecular interactions and mechanism of action of Trp3 in lipid bilayers and biological membranes. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.Univ São Paulo, Inst Chem, Dept Biochem, Struct Biol Lab, BR-05513970 São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05389970 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04044020 São Paulo, BrazilWeb of Scienc

    Two-dimensional Quantum Black Holes, Branes in BTZ and Holography

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    We solve semiclassical Einstein equations in two dimensions with a massive source and we find a static, thermodynamically stable, quantum black hole solution in the Hartle-Hawking vacuum state. We then study the black hole geometry generated by a boundary mass sitting on a non-zero tension 1-brane embedded in a three-dimensional BTZ black hole. We show that the two geometries coincide and we extract, using holographic relations, information about the CFT living on the 1-brane. Finally, we show that the quantum black hole has the same temperature of the bulk BTZ, as expected from the holographic principle.Comment: 10 pages, 2 figures, RevTex, ``point particle of mass \mu '' changed with ``massive boundary source'' for better clarity. Action in (50) written in Z_2 symmetric form. Appendix clarified. Minor corrections and references added. Version accepted for pubblication in PRD15 (2006

    Positive effects of robotic exoskeleton training of upper limb reaching movements after stroke

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    This study, conducted in a group of nine chronic patients with right-side hemiparesis after stroke, investigated the effects of a robotic-assisted rehabilitation training with an upper limb robotic exoskeleton for the restoration of motor function in spatial reaching movements. The robotic assisted rehabilitation training was administered for a period of 6 weeks including reaching and spatial antigravity movements. To assess the carry-over of the observed improvements in movement during training into improved function, a kinesiologic assessment of the effects of the training was performed by means of motion and dynamic electromyographic analysis of reaching movements performed before and after training. The same kinesiologic measurements were performed in a healthy control group of seven volunteers, to determine a benchmark for the experimental observations in the patients’ group. Moreover degree of functional impairment at the enrolment and discharge was measured by clinical evaluation with upper limb Fugl-Meyer Assessment scale (FMA, 0–66 points), Modified Ashworth scale (MA, 0–60 pts) and active ranges of motion. The robot aided training induced, independently by time of stroke, statistical significant improvements of kinesiologic (movement time, smoothness of motion) and clinical (4.6 ± 4.2 increase in FMA, 3.2 ± 2.1 decrease in MA) parameters, as a result of the increased active ranges of motion and improved cocontraction index for shoulder extension/flexion. Kinesiologic parameters correlated significantly with clinical assessment values, and their changes after the training were affected by the direction of motion (inward vs. outward movement) and position of target to be reached (ipsilateral, central and contralateral peripersonal space). These changes can be explained as a result of the motor recovery induced by the robotic training, in terms of regained ability to execute single joint movements and of improved interjoint coordination of elbow and shoulder joints
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