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

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

Photodynamics of azobenzene in a hindering environment

We have run trajectory surface hopping simulations of the trans-cis photoisomerization of azobenzene, subject to a pulling force. The model mimics two situations: a trans-azobenzene derivative with bulky substituents that may not be easily displaced, and a recent experiment by Gaub’s group [T. Hugel, N.B. Holland, A. Cattani, L. Moroder, M. Seitz, H.E. Gaub, Science 296 (2002) 1103; N.B. Holland, T. Hugel, G. Neuert, A. Cattani-Scholz, C. Renner, D. Oesterhelt, L. Moroder, M. Seitz, H.E. Gaub, Macromolecules 36 (2003) 2015; G. Neuert, T. Hugel, R.R. Netz, H.E. Gaub, Macromolecules 39 (2005) 789], in which a polymer with azobenzene units was stretched in an atomic force microscope. In both cases, the shortening of the azobenzene moiety in going from the trans to the cis form is opposed by a pulling force. Our simulations show that the trans-cis photoconversion is only partially suppressed by con- siderably large forces (500 pN or more). However, the cis isomer reverts to trans in the ground state, with the help of the pulling force and using the vibrational energy that is available in the first 1–2 ps. The lowering of the quantum yields is therefore the combined result of hindering of the excited state process and of the hot ground state back reaction

Robotic training can improve coordination and muscular activation in chronic hemiplegic stroke

Vengono studiate le modificazioni cinematiche del movimento volontario indotto da training robotico in un campione di pazienti emiplegic

Identification of movement phenotypes from occupational gesture kinematics: Advancing individual ergonomic exposure classification and personalized training

The identification of personalized preventive strategies plays a major role in contrasting the occurrence of work-related musculoskeletal disorders. This requires the identification of distinct movement patterns within large samples and the attribution of a proper risk level to each identified movement phenotype. We assessed the feasibility of this approach by exploiting wearable inertial measurement units to estimate the whole-body kinematics of 43 healthy participants performing 18 reach-to-manipulate movements, which differed based on the object's position in the space and the type of manipulation required. Through unsupervised clustering, we identified multiple movement phenotypes graded by ergonomic performance. Furthermore, we determined which joints mostly contributed to instantiating the ergonomic differences across clusters, emphasizing the importance of monitoring this aspect during occupational gestures. Overall, our analysis suggests that movement phenotypes can be identified within occupational motor repertoires. Assigning individual performance to specific phenotypes has the potential to inform the development of more effective and tailored interventions

Phos project: Lesson learned from experimenting a pulsating heat pipe on board a sounding rocket (REXUS18) and refurbishment strategies

PHOS Project (www.phosproject.com) was launched on March 18th, 2015, from the Esrange Space Center (SSC) in Kiruna, Sweden. The aim of the project was to test two Closed Loop Pulsating Heat Pipes (CLPHPs) in 90 seconds microgravity experienced on board REXUS18 sounding rocket. The REXUS/BEXUS programme is realised under a bilateral Agency Agreement between the German Aerospace Centre (DLR) and the Swedish National Space Board (SNSB). The programme offers a unique opportunity for students to get in touch with research activities and engineering challenges related to the space field. Despite PHOS Project short duration (20 Months) with respect to real space projects of larger scale, several challenges was encountered related both to the technical implementation (design, development, manufacturing and testing) of the experimental system to be interfaced to the rocket and to the programmatic and organizational aspects (management, team working, cost analysis, industrial cooperation). In the present paper, the design of the experimental set-up and the experimental results are briefly discussed, even though it was not possible to experience the expected low gravity conditions due to a failure of the rocket's yo-yo de-spin system. Moreover, all the lesson learned related to the project development are properly recognized and listed, highlighting efforts and learning curve of the junior team members to respect mandatory deadlines and reviews. With these reported lessons learned, this paper could be a basis for future Student teams that intend to participate a stimulating programme like REXUS/BEXUS. The implementation issues encountered and the trade-offs analysis, which has been made between different design solutions in order to meet mission requirements, are reported. Finally storage constraints and a refurbishment strategy for possible future re-flight are described