Variable gap device and method of manufacture

A variable gap device which comprises a suitable material with a cavity formed therein mounted over a body. Elements are formed on the surface of the body and on the top surface of the cavity. In one embodiment, the elements are electrodes of a variable capacitance device, and in another embodiment the elements are partial or total reflectors of incident light from an optical fiber. The surface of the cavity opposite the body is preferably flat and of the order of microns from the body. The device is fabricated by forming a removable layer over a temporary substrate. An appropriate element pattern is formed over the removable layer and the layer is etched in a configuration which will define the cavity. The deformable material is encapsulated over this structure and then removed from the substrate with the element remaining in the cavity. Any removable material remaining in the cavity can then be etched away.Published versio

Neuroplastic Changes Following Brain Ischemia and their Contribution to Stroke Recovery: Novel Approaches in Neurorehabilitation

Ischemic damage to the brain triggers substantial reorganization of spared areas and pathways, which is associated with limited, spontaneous restoration of function. A better understanding of this plastic remodeling is crucial to develop more effective strategies for stroke rehabilitation. In this review article, we discuss advances in the comprehension of post-stroke network reorganization in patients and animal models. We first focus on rodent studies that have shed light on the mechanisms underlying neuronal remodeling in the perilesional area and contralesional hemisphere after motor cortex infarcts. Analysis of electrophysiological data has demonstrated brain-wide alterations in functional connectivity in both hemispheres, well beyond the infarcted area. We then illustrate the potential use of non-invasive brain stimulation (NIBS) techniques to boost recovery. We finally discuss rehabilitative protocols based on robotic devices as a tool to promote endogenous plasticity and functional restoration

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

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

Performance Analysis of Dual 5 GHz WiFi and UHF TV White Space Network Links

Commonly used WiFi is known to be ill-suited for penetrating vegetation and buildings and non-line-of-sight conditions. Television white space (TVWS) operates in ultra-high frequency (UHF) bands that overcome many of the penetration and line-of-sight challenges found in the 2.4 GHz and 5 GHz bands normally used by WiFi. The aim of this study is to report on the performance of WiFi technology in the 5 GHz band and the TVWS technology in the 600 MHz UHF TV band as well as a combination of both radios in two different scenarios, short-range clear line-of-sight, and non-line-of-sight conditions. A number of performance metrics, such as estimated throughput, bitrate, signal strength, noise, transmit power, transmit error, packet loss, and round trip time, are compared for varied distances and increasing levels of vegetation in the propagation path. Both TVWS and WiFi experiments showed increased sensitivity to noise as channel widths increased with TVWS being particularly susceptible to noise in nearby channels from powerful TV transmitters. Aggregating the WiFi and TVWS radios proved to have the best performance improvements when the WiFi and TVWS links had similar throughput in line-of-sight conditions

TVWS Devices Spectrum Mask Test and Analysis

Dynamic Spectrum Access (DSA) plays a vital role in opportunistic access to spectrum. A key component of DSA is preventing interference to the incumbent (primary) user from the secondary user. We present the results of an experiment to analyze the output signal and spectral mask of a low-cost TVWS device at specific power levels and specific channels in order to evaluate its potential level of interference to primary users