WAKE-Up Exoskeleton to Assist Children With Cerebral Palsy: Design and Preliminary Evaluation in Level Walking.

This paper presents the modular design and control of a novel compliant lower limbmulti-joint exoskeleton for the rehabilitation of ankle kneemobility and locomotion of pediatric patients with neurological diseases, such as Cerebral Palsy (CP). The device consists of an untethered powered knee-ankle-foot orthosis (KAFO), addressed as WAKE-up (Wearable Ankle Knee Exoskeleton), characterized by a position control and capable of operating synchronously and synergistically with the human musculoskeletal system. The WAKE-up mechanical system, control architecture and feature extraction are described. Two test benches were used to mechanically characterize the device. The full system showed a maximum value of hysteresis equal to 8.8% and a maximum torque of 5.6 N m/rad. A pre-clinical use was performed, without body weight support, by four typically developing children and three children with CP. The aims were twofold: 1) to test the structure under weight-bearing conditions and 2) to ascertain its ability to provide appropriate assistance to the ankle and the knee during overground walking in a real environment. Results confirm the effectiveness of the WAKE-up design in providing torque assistance in accordance to the volitionalmovements especially in the recovery of correct foot landing at the start of the gait cycle.

Influence of robotic shoal size, configuration, and activity on zebrafish behavior in a free-swimming environment.

In animal studies, robots have been recently used as a valid tool for testing a wide spectrum of hypotheses. These robots often exploit visual or auditory cues to modulate animal behavior. The propensity of zebrafish, a model organism in biological studies, toward fish with similar color patterns and shape has been leveraged to design biologically inspired robots that successfully attract zebrafish in preference tests. With an aim of extending the application of such robots to field studies, here, we investigate the response of zebrafish to multiple robotic fish swimming at different speeds and in varying arrangements. A soft real-time multi-target tracking and control system remotely steers the robots in circular trajectories during the experimental trials. Our findings indicate a complex behavioral response of zebrafish to biologically inspired robots. More robots produce a significant change in salient measures of stress, with a fast robot swimming alone causing more freezing and erratic activity than two robots swimming slowly together. In addition, fish spend more time in the proximity of a robot when they swim far apart than when the robots swim close to each other. Increase in the number of robots also significantly alters the degree of alignment of fish motion with a robot. Results from this study are expected to advance our understanding of robot perception by live animals and aid in hypothesis-driven studies in unconstrained free-swimming environments.

Is Montgomery tracheal Safe-T-Tube clinical failure induced by biofilm?

OBJECTIVES: Montgomery Safe-T-Tube deterioration and early biofilm colonization may explain the discomfort claimed by many patients and clinical failures. The aim of the study was to analyze the deterioration of Montgomery Safe-T-Tube morphological and mechanical properties in vivo in 16 patients by using microbiological methods, optical and electron microscopy, and engineering tests. STUDY DESIGN: Prospective controlled study at a single medical center. SETTING: University hospital. SUBJECTS AND METHODS: The study, conducted from April 2007 to February 2012 at the "Sapienza" University of Rome, was designed to collect 2 Montgomery Safe-T-Tubes from each patient. The first was removed 3 to 15 days after insertion (group A) and the second at least 90 days after (group B). Specimens underwent microbiologic assays, electron microscopic analysis, immunocytologic analysis, and mechanical tests. RESULTS: Microorganisms were not isolated in 2 group A cases (12%), whereas they were in all group B cases. Biofilm was identified in 11 of 16 (69%) group A samples and in 16 of 16 (100%) group B samples (P = .0149) using scanning electron microscopy. Immunohistochemistry showed monocyte-granulocyte line cells producing interleukin-1ß on the external surfaces of Montgomery Safe-T-Tubes. The tensile test showed that the wear related to the longer period of use makes Montgomery Safe-T-Tubes more rigid than newer ones. CONCLUSION: Early biofilm colonization takes place in Montgomery Safe-T-Tubes in most cases. The mechanical decay could be justified in part by the destructive biofilm activity and by the release of inflammatory effectors and enzymes.