In an electromyographic and muscle force (EMG-Force) model, the variability and uncertainty of the input muscle parameters increase the difficulty of assessing this type of model. In this study, a Monte Carlo method is used to evaluate the robustness and the sensitivity of an EMG-Force model, recently developed by our team, for two groups of simulations (constant and sinusoidal force contractions). Two existing criteria (EMG/force and force/force-variability relations) and a new criterion derived from this model (Root Mean Square error, Error(RMS), between the force command and the generated force) are used to extract relevant simulations and obtain the optimized parameter ranges in constant force contractions, while only the new criterion could be valuable in sinusoidal force contractions. The comparison of obtained results from the two groups of simulations has shown that the new criterion can replace the two existing criteria in constant and sinusoidal force contractions to give rise to stable optimized input parameter ranges for the studied EMG-Force model.
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http://dx.doi.org/10.1109/IEMBS.2009.5334099 | DOI Listing |
J Neurophysiol
January 2025
Department of Integrative Physiology, University of Colorado Boulder.
Our purpose was to compare the influence of the spectral content of motor unit recordings on the calculation of electromechanical delay and on the prediction of force fluctuations from measures of the variability in discharge times and neural drive during steady isometric contractions with the first dorsal interosseus muscle. Participants ( = 42; 60 ± 13 yrs) performed contractions at 5% and 20% MVC. After satisfying inclusion criteria, high-density surface EMG recordings from a subset of 23 participants were decomposed into the discharge times of 530 motor units.
View Article and Find Full Text PDFSmall
January 2025
State Key Laboratory of Biocatalysis and Enzyme Engineering, Stem Cells and Tissue Engineering Manufacture Center, School of Life Science, Hubei University, Wuhan, Hubei, 430062, China.
Recent advances in drug design and compound synthesis have highlighted the increasing need for effective methods of toxicity evaluation. A specialized force sensor, known as the light wavelength-encoded "Chinese guzheng" is developed. This innovative sensor is equipped with optical fiber strings and utilizes a wavelength-encoded fiber Bragg grating (FBG) that is chemically etched to reduce its diameter.
View Article and Find Full Text PDFTissue Eng Regen Med
January 2025
Department of Physiology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.
Background: Direct reprogramming of fibroblasts into chemically induced cardiomyocyte-like cells (CiCMs) through small molecules presents a promising cell source for cardiac regeneration and therapeutic development. However, the contaminating non-cardiomyocytes, primarily unconverted fibroblasts, reduce the effectiveness of CiCMs in various applications. This study investigated a metabolic selection approach using lactate to enrich CiCMs by exploiting the unique metabolic capability of cardiomyocytes to utilize lactate as an alternative energy source.
View Article and Find Full Text PDFSoft Matter
January 2025
LENS (European Laboratory for Non-Linear Spectroscopy) Via Nello Carrara 1, 50019 Sesto Fiorentino (FI), Italy.
Liquid Crystalline Networks (LCNs) are widely investigated to develop actuators, from soft robots to artificial muscles. Indeed, they can produce forces and movements in response to a plethora of external stimuli, showing kinetics up to the millisecond time-scale. One of the most explored preparation technique involves the photopolymerization of an aligned layer of reactive mesogens.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Sensor and Actuator Systems, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden.
Electropolymerized polypyrrole (PPy) is considered as one of the promising polymers for use in ionic-electroactive or conducting polymer (CP) actuators. Its electromechanical properties surpass those of other prominent CPs such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS) or polyaniline. However, freestanding and linear contracting actuator fibers made solely of electropolymerized PPy are not available yet.
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