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Michael Taynnan Barros

Publications and source records attributed to Michael Taynnan Barros.

20 records · Page 2Linked to original sources

The Multi-Scale Impact of the Alzheimer's Disease in the Topology Diversity of Astrocytes Molecular Communications Nanonetworks

The Internet of Bio-Nano-Things is a new paradigm that can bring novel remotely controlled actuation and sensing techniques inside the human body. Towards precise bionano sensing techniques in the brain, we investigate the challenges of modelling spatial distribution of astrocyte networks in developing a mathematical framework that lay the groundwork for future early-detection techniques of neurodegenerative disease. In this paper, we investigate the effect of the $β$-amyloid plaques in astrocytes with the Alzheimer's disease. We developed a computation model of healthy and Alzheimer's diseases astrocytes networks from the state of the art models and results that account for the intracellular pathways, IP$_3$ dynamics, gap junctions, voltage-gated calcium channels and astrocytes volumes. We also implemented different types of astrocytes network topologies including shortcut networks, regular degree networks, Erdös Rényi networks and link radius networks. A proposed multi-scale stochastic computational model captures the relationship between the intracellular and intercellular scales. Lastly, we designed and evaluated a single-hop communication system with frequency modulation using metrics such as propagation extend, molecular delay and channel gain. The results show that the more unstable but at the same time lower level oscillations of Alzheimer's astrocyte networks can create a multi-scale effect on communication between astrocytes with increased molecular delay and lower channel gain compared to healthy astrocytes, with an elevated impact on Erdös Rényi networks and link radius networks topologies.

cs.ET↗

Wireless Optogenetic Nanonetworks: Device Model and Charging Protocols

In recent years, numerous research efforts have been dedicated towards developing efficient implantable devices for brain stimulation. However, there are limitations and challenges with the current technologies. Firstly, the stimulation of neurons currently is possible through implantable electrodes but limited to a population of neurons. Secondly, a major hurdle lies in developing miniature devices that can last for a lifetime in the patient's brain. In parallel, Optogenetics has emerged proposing the stimulation of neurons using light by means of optical fibers inserted through the skull. Many challenges are thus introduced in terms of suitability to patient's lifestyle and biocompatibility. We have recently proposed the concept of wireless optogenetic nanonetworking devices (WiOptND), addressing these long-term deployment problems, and at the same time targeting single neuron stimulation [1]. The WiOptND is equipped with a miniature LED that is able to stimulate a genetically engineered neuron while harvesting energy from ultrasonic vibrations. This paper investigates how light propagates in the brain tissue, and based on the power required to emit sufficient intensity for stimulation, an energy harvesting circuitry is designed. A number of charging protocols are also proposed to maximize energy efficiency while ensuring minimum number of neural spike misfirings. These protocols include the Charge and Fire, the Predictive Sliding Detection Window, and its variant Markov-Chain based Time-Delay Patterns. Simulation results show the drop of stimulation ratio for 25% and more stable trend in its efficiency ratio are exhibited on Markov-Chain based Time-Delay Patterns compared to Change and Fire. The results show the feasibility of utilizing WiOptND for long-term implants, and a new direction towards precise stimulation of neurons in the cortical columns of the brain.

cs.ET↗