Drug delivery devices have revolutionized the course of therapeutic treatment in the recent past. These devices provide a firm foundation for diverse strategies to overcome the limitations of systemic administration that cannot provide a high drug potency at the specific disease infected body tissues. The ongoing developments in the pharmaceutical industry have focused on exploring the reliable actuating mechanisms that can provide therapy and dispense drugs precisely to control therapeutic effects with minimum toxicity. The wireless actuation of drug delivery devices has been considered as an intervening noninvasive approach to release encapsulated drug compounds. This review paper highlights implantable and transdermal drug delivery devices that are based on wirelessly controlled microchips, micropumps, microvalves, and magnetic robots. Their key features, such as working principle, dimensions, materials, operating frequency, and wireless actuation through radio frequency for drug delivery are explained. The interaction of radio waves with electrically conductive and magnetic nanoparticles is also discussed for drug delivery. Furthermore, the radio frequency assisted data telemetry and wireless power transfer techniques are elucidated for drug delivery devices. The opportunities to enhance the patients' control on therapeutic indexes and release mechanisms are still possible by incorporating advanced wireless sensors for concocting future innovations in the wirelessly controlled drug delivery devices.
Wireless capsule endoscopy (WCE) systems are used to capture images of the human digestive tract for medical applications. The antenna is one of the most important components in a WCE system. In this paper, we present novel small antenna solutions for a WCE system operating at the 433 MHz ISM band along with a link budget analysis. The in-body capsule transmitter uses an ultrawideband outer-wall conformal loop antenna, whereas the on-body receiver uses a printed monopole antenna with a partial ground plane. A colon-equivalent tissue phantom and CST Gustav voxel human body model were used for the numerical studies of the capsule antenna. The simulation results in the colon-tissue phantom were validated through in-vitro measurements using a liquid phantom. According to the phantom simulations, the capsule antenna has −10 dB impedance matching from 309 to 1104 MHz. The ultrawideband characteristic enables the capsule antenna to tolerate the detuning effects due to electronic modules in the capsule and due to the proximity of various different tissues in gastrointestinal tracts. The same design methodology was applied to on-body antennas followed by in-vitro and ex-vivo measurements for validation. The on-body antenna exceeds −10 dB impedance matching from 385 MHz to 502 MHz both in simulations and measurements. The path loss for the radio link between an in-body capsule transmitter and an on-body receiver using our antenna solutions, in simulations and measurements, is less than 50 dB for any capsule orientation and location, ensuring sufficient signal level at the receiver, hereby enabling an improved capsule endoscope.Index Terms-Conformal antenna, in-to-on body propagation, wireless capsule endoscope.
Emotion states recognition using wireless signals is an emerging area of research that has an impact on neuroscientific studies of human behaviour and well-being monitoring. Currently, standoff emotion detection is mostly reliant on the analysis of facial expressions and/or eye movements acquired from optical or video cameras. Meanwhile, although they have been widely accepted for recognizing human emotions from the multimodal data, machine learning approaches have been mostly restricted to subject dependent analyses which lack of generality. In this paper, we report an experimental study which collects heartbeat and breathing signals of 15 participants from radio frequency (RF) reflections off the body followed by novel noise filtering techniques. We propose a novel deep neural network (DNN) architecture based on the fusion of raw RF data and the processed RF signal for classifying and visualising various emotion states. The proposed model achieves high classification accuracy of 71.67% for independent subjects with 0.71, 0.72 and 0.71 precision, recall and F1-score values respectively. We have compared our results with those obtained from five different classical ML algorithms and it is established that deep learning offers a superior performance even with limited amount of raw RF and post processed time-sequence data. The deep learning model has also been validated by comparing our results with those from ECG signals. Our results indicate that using wireless signals for stand-by emotion state detection is a better alternative to other technologies with high accuracy and have much wider applications in future studies of behavioural sciences.
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This paper presents a novel beam steerable array antenna that encompasses fully planar, low profile and lightweight characteristics for satellite communication (SatCom) applications. The proposed array contains a wideband linear source generator (LSG), an array of circular patches, and an inductive surface. The LSG is designed based on the substrate-integrated-waveguide (SIW) technology, whereas the patches are regarded as coupling circular scatterers, placed on the inductive surface for converting surface wave into the radiating wave. Each scatterer acts as a location-dependent phaser that can tailor the farfield behaviour to leverage beam steering, and is achieved by changing its distribution mechanically. A prototype of the proposed design has been fabricated and measured to evaluate the antenna performance. The measured results are in good agreement with the simulated results. The array antenna operates well with S 11 <-10 dB in the frequency band of 10.75-12.5 GHz and has stable radiation performance with beam steering capability of nearly ±60 • in the elevation plane. The total height of the proposed array is about 5.1 mm (0.19λ •). It is envisaged that the proposed antenna array will empower small moving platforms due to low cost, low profile and suitability for mass production. INDEX TERMS Array antenna, beam steering, low-profile, satellite communication, substrate-integrated waveguide (SIW).
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