1,721,054 research outputs found
Analisi e sintesi di Central Pattern Generator
No full textNegli esseri viventi, un Central Pattern Generator (CPG) è una rete di neuroni
relativamente piccola, in grado di produrre pattern ritmici anche in assenza di
feedback sensoriali o di segnali provenienti dal sistema nervoso centrale. Queste
reti hanno un ruolo fondamentale nella regolazione di molte attività ritmiche,
come per esempio la nuotata, la respirazione, la masticazione e la locomozione.
Lo studio di queste reti è di interesse per diverse discipline, non solo per la loro
valenza biologica, ma anche per le loro possibili applicazioni alla riabilitazione e
al controllo di robot biologicamente ispirati. In questa tesi sono proposti alcuni
strumenti per l'analisi, la riduzione, la sintesi e l'emulazione circuitale di tali reti
neuronali. In particolare, i tool proposti sono stati applicati ad un caso di studio
in cui ci si è concentrati sul CPG responsabile della locomozione dei topi
A Preliminary Propagation Study on Magnetic Scaffolds for Microwave Theranostics
Full text linkMicrowave hyperthermia is a promising therapeutic modality in oncology against deep-seated tumors such as bone cancers. However, antennas and radiating sources fails in providing the therapeutic heat without affecting the healthy tissues. Magnetic nanocomposite biomaterials, called magnetic scaffolds, can be implanted to be used as hyperthermia agents. The possibility of using magneto-dielectric biocompatible implant for performing microwave hyperthermia has been poorly investigated. Furthermore, the possibility of using magnetic scaffolds as microwave-responsive theranostic agents has never been explored. In other words, if and how the change of magnetic properties during the hyperthermia treatment could be detected by using microwave signal has been not investigated so far. In this work, a simplified mono-dimensional electromagnetic propagation model in a multilayer structure by means of the wave-amplitude transmission method has been proposed. The properties of the bolus-matching medium, a suitable set of working frequency for performing the hyperthermia treatment and the monitoring with microwaves has been found. The temperature increase in the tumor and scaffold have been simulated. Then, through the differential analysis of the variation of the transmission coefficient during the treatment it has been preliminarily determined that magnetic scaffolds could be used as microwave theranostic agents
Modelling of Magnetic Scaffolds for RF Hyperthermia of Deep-Seated Tumors
No full textDeep seated tumors are neoplasms grown in challenging sites that call for innovative interventional strategies. Thanks to the development of magnetic nanocomposite biomaterials, multifunctional electromagnetic-responsive thermoseeds, called magnetic scaffolds, can be used as hyperthermia agents to control the local recurrence rate of deep-seated cancers through radiofrequency (RF) heating. To achieve an effective and high-quality treatment, the planning through multiphysics simulations is mandatory. A computational framework for solving the coupled electromagnetic and thermal phenomena ruling the RF heating of magnetic scaffolds will be presented and used to study different biomaterials, physiopathological scenarios and applications
Design principles for central pattern generators with preset rhythms
No full textThis article is concerned with the design of synthetic central pattern generators (CPGs). Biological CPGs are neural circuits that determine a variety of rhythmic activities, including locomotion, in animals. A synthetic CPG is a network of dynamical elements (here called cells) properly coupled by various synapses to emulate rhythms produced by a biological CPG. We focus on CPGs for locomotion of quadrupeds and present our design approach, based on the principles of nonlinear dynamics, bifurcation theory, and parameter optimization. This approach lets us design the synthetic CPG with a set of desired rhythms and switch between them as the parameter representing the control actions from the brain is varied. The developed four-cell CPG can produce four distinct gaits: walk, trot, gallop, and bound, similar to the mouse locomotion. The robustness and adaptability of the network design principles are verified using different cell and synapse models
Behavioral models for ferrite-core inductors in switch-mode DC-DC power supplies: a survey
No full textThe First (of a Long Series) Nano Student Design Competition
No full textThe IEEE Nanotechnology Council (NTC) has marked its 25th anniversary by fostering educational initiatives for students and young professionals. Among these efforts, the Nano Student Design Competition (Nano SDC) was introduced during the 24th IEEE International Conference on Nanotechnology (IEEE NANO 2024) in Gijon, Spain. Nano SDC is a platform for student teams to design practical solutions to challenges in nanoscience and nanotechnology, guided by NTC Technical Committees. Participants showcase their prototypes, software, or methodologies at the conference, fostering innovation and collaboration. The inaugural competition included awarded projects ranging from flexible graphene-based infrared photodetectors to software for graphene fabrication, with winners gaining opportunities to publish their work in the IEEE Nanotechnology Magazine. Building on its success, Nano SDC is set to become a recurring highlight of IEEE NANO conferences, aiming to enhance student participation and create a sustainable, dynamic network within the nanotechnology community. The next edition will take place at IEEE NANO 2025 in Washington, D.C., continuing its mission to inspire and engage the next generation of nanotechnologists
Enhancement of Cell Migration Rate Toward a Superparamagnetic Scaffold Using LF Magnetic Fields
No full textRecently developed superparamagnetic scaffolds for bone tissue engineering are still a complex object to deal with. Thanks to the possibility of controlling them remotely and directing therapeutic action in a non-invasive way, this work deals with the necessity of a clear definition and quantification of the field gradient, the forces and velocity it could exert on magnetic nanocarriers in a static magnetic field, and the heat and power generated when a time-varying field is applied, better defining the frequency response of magnetic nanoparticles entrapped in a solid matrix
A Low-Cost Free-Space Optical Communication Prototype
No full textIn this paper a prototype of a free-space optical communication system is proposed. The transmitter is equipped with a blue 1W LED and a low-cost microcontroller implementing a digital modulation scheme. The receiver converts the incoming light into a current through a photodiode and another identical microcontroller is employed to demodulate and decode the signal, after proper analog amplification and filtering. The system is thought to be used underwater for communication, e.g., between an autonomous underwater vehicle and a buoy. Preliminary results in air are shown to validate the functioning of the system with different values of solar illuminance
Design of Synthetic Central Pattern Generators Producing Desired Quadruped Gaits
No full textThis paper is concerned with a method for design and analysis of specific neuronal networks, called central pattern generators (CPGs), which produce primary rhythmic patterns in animals. In particular, the paper is focused on synthetic CPGs made up of few basic elements and governing quadrupeds' gaits and gait transitions, under the control of an external drive. The method combines principles of bifurcation theory, geometric properties of symmetry, and numerical analysis based on the recently proposed toolbox CEPAGE. The method is applied to two CPGs, one bio-inspired and one purely synthetic. In both cases, the method provides a way to obtain a desired sequence of gaits by continuously changing a bifurcation parameter related to the external drive
Model-based compensation of rate-dependent hysteresis in a piezoresistive strain sensor
No full textThis paper is concerned with modeling of smart textiles, aimed at compensating their intrinsic nonlinearities. In particular, a new model is proposed to compensate for hysteresis and relaxation in strain sensors made of Electrolycra. These sensors are increasingly employed in emerging areas such as wearable electronics and soft robotics for their simple transduction mechanism and low cost. However, being intrinsically nonlinear, the signals measured from these devices need some processing, in order to increase their sensing accuracy. Here, we propose a new model for the compensation of the main distortions intrinsic to these soft sensors, which are mainly caused by hysteresis and relaxation, whose combined effect produces rate-dependent hysteresis. The model capabilities are tested on experimental data measured on Electrolycra. The comparisons with the results obtained with two different models witness the good behavior of the proposed model
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