8 research outputs found

    A Thermoacoustic Model for High Aspect Ratio Nanostructures

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    In this paper, we have developed a new thermoacoustic model for predicting the resonance frequency and quality factors of one-dimensional (1D) nanoresonators. Considering a nanoresonator as a fix-free Bernoulli-Euler cantilever, an analytical model has been developed to show the influence of material and geometrical properties of 1D nanoresonators on their mechanical response without any damping. Diameter and elastic modulus have a direct relationship and length has an inverse relationship on the strain energy and stress at the clamp end of the nanoresonator. A thermoacoustic multiphysics COMSOL model has been elaborated to simulate the frequency response of vibrating 1D nanoresonators in air. The results are an excellent match with experimental data from independently published literature reports, and the results of this model are consistent with the analytical model. Considering the air and thermal damping in the thermoacoustic model, the quality factor of a nanowire has been estimated and the results show that zinc oxide (ZnO) and silver-gallium (Ag2Ga) nanoresonators are potential candidates as nanoresonators, nanoactuators, and for scanning probe microscopy applications

    Dynamic detection and reversal of myocardial ischemia using an artificially intelligent bioelectronic medicine

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    Potentially damaging “heart stress” is reversed using reactive nerve stimulation controlled by artificial intelligence. Myocardial ischemia is spontaneous, frequently asymptomatic, and contributes to fatal cardiovascular consequences. Importantly, myocardial sensory networks cannot reliably detect and correct myocardial ischemia on their own. Here, we demonstrate an artificially intelligent and responsive bioelectronic medicine, where an artificial neural network (ANN) supplements myocardial sensory networks, enabling reliable detection and correction of myocardial ischemia. ANNs were first trained to decode spontaneous cardiovascular stress and myocardial ischemia with an overall accuracy of ~92%. ANN-controlled vagus nerve stimulation (VNS) significantly mitigated major physiological features of myocardial ischemia, including ST depression and arrhythmias. In contrast, open-loop VNS or ANN-controlled VNS following a caudal vagotomy essentially failed to reverse cardiovascular pathophysiology. Last, variants of ANNs were used to meet clinically relevant needs, including interpretable visualizations and unsupervised detection of emerging cardiovascular stress. Overall, these preclinical results suggest that ANNs can potentially supplement deficient myocardial sensory networks via an artificially intelligent bioelectronic medicine system
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