A digital twin framework for robust control of robotic-biological systems.

Medical device regulatory standards are increasingly incorporating computational modelling and simulation to accommodate advanced manufacturing and device personalization. We present a method for robust testing of engineered soft tissue products involving a digital twin paradigm in combination with robotic systems. We developed and validated a digital twin framework for calibrating and controlling robotic-biological systems. A forward dynamics model of the robotic manipulator was developed, calibrated, and validated. After calibration, the accuracy of the digital twin in reproducing the experimental data improved in the time domain for all fourteen tested configurations and improved in frequency domain for nine configurations. We then demonstrated displacement control of a spring in lieu of a soft tissue element in a biological specimen. The simulated experiment matched the physical experiment with 0.09 mm (0.001%) root-mean-square error for a 2.9 mm (5.1%) length change. Finally, we demonstrated kinematic control of a digital twin of the knee through 70-degree passive flexion kinematics. The root-mean-square error was 2.00°, 0.57°, and 1.75° degrees for flexion, adduction, and internal rotations, respectively. The system well controlled novel mechanical elements and generated accurate kinematics in silico for a complex knee model. This calibration method could be applied to other situations where the specimen is poorly represented in the model environment (e.g., human or animal tissues), and the control system could be extended to track internal parameters such as tissue strain (e.g., control knee ligament strain). Further development of this framework can facilitate medical device testing and innovative biomechanics research.

Passive Knee Orthoses Assistance in Functional Electrical Stimulation Cycling in an Individual With Spinal Cord Injury.

Functional Electrical Stimulation (FES) may be used in rehabilitation and assistance of people with Spinal Cord Injury (SCI). One significant application is facilitating physical exercise, mainly when combining FES with mechanical platforms, such as tricycles. However, there are still technical challenges in FES cycling protocols, such as improving control and cycling performance. Here we show how passive elements in knee orthoses during FES cycling could increase the average cadence, taking advantage of the cycling movement. Our approach is twofold. First, we simulated the forward dynamics of a detailed musculoskeletal model with passive elements over the knees. Simulations showed that specific spring stiffness ranges increased the crankset speed during cycling by more than 50%. Using parameters found in simulations, we built a pair of passive orthoses and performed experiments with one individual with SCI. During two days, the volunteer cycled with similar stimulation magnitude with and without the passive elements. We observed that the average crankset speed was higher by more than 10% when the springs were attached to the passive orthoses. These results show the potential of using passive elements to increase cycling speed for FES cycling with similar or even lower stimulation magnitude, leading to longer exercise duration.

Assessment of iodine importance and needs for supplementation in school-aged children in Portugal.

BACKGROUND: Micronutrients are essential for child proper growth and development. Nutritional deficiencies of these elements have increasingly been a concern in Europe, as they are often related to the cognitive potential and physical lifelong consequences. However, being an essential trace element for thyroid function, iodine intake in the desired quantities becomes also very important for neurodevelopment, including for school-aged children. Therefore, the aim of this paper is to highlight the need for wider dissemination of the physiological importance of iodine among health professionals and the general population as well as the knowledge of iodine needs and possible supplementation within families with school-aged children. METHODS: The present study is an observational, descriptive, cross-sectional evaluation of knowledge and perceptions of iodine physiological importance. An evaluation survey has been carried out based on knowledge of iodine needs and possible supplementation within families with school-aged children. It has been target at mothers with school-age children under 18 years old with residence in Portugal. Data are represented as frequency and percentages and association between variables was measured. RESULTS: The internet survey has been answered by around 691 mothers, corresponding to 811 children data validated; 47% (n = 381) girls and 53% (n = 430) boys. Mother's knowledge about iodine and the importance for the improvement of learning capacity is not independent of having health study/work area (χ2 at the 0.05 level). Nevertheless, it can be observed a slight association between mothers who agree with iodine supplementation and those who effectively supplement their child (χ2 9.315; Φ 0.116). Although use of iodized kitchen salt certainly changes the balance from sub-optimal to adequate iodine nutrition, only 8.8% (n = 61) reported using iodized salt. However, 87.6% (n = 605) assumed salt iodization importance without information. CONCLUSIONS: We believe that the findings of this survey have great public health importance for Portugal. While many countries have mandatory iodizes salt programmes, in Portugal iodine supplementation is not a current practice. Therefore, we suggest an urgent evaluation of iodine in Portugal, namely for school-aged children, where iodine deficiencies are critical, as well as a systematic information dissemination as a form of publicizing iodine supplementation needs.