Deeply Implanted Conformal Antenna for Real-Time Bio-Telemetry Applications.

The design and experimental verification of a deeply implanted conformal printed antenna is presented. The hip implant acts as the ground plane for a coaxial-cable-fed trapezoidal radiator designed to transmit biological signals collected within the body by proper biosensors. The arrangement, consisting of a metallic (or equivalent) hip implant, bio-compatible gypsum-based dielectric, and conformal radiator, was tested when the hosting 3D-printed plastic bone was immersed in tissue-like liquid contained in a plastic bucket. The dimensions of the set-up are similar to a human leg. Matching and radiation characteristics are presented in the industrial, scientific, and medical (ISM) frequency band (2.4-2.5 GHz), showing the feasibility of the proposed arrangement.

Circularly polarized differential intra-oral antenna design validation and characterization for tongue drive system.

Assistive devices are becoming increasingly popular for physically disabled persons suffering tetraplegia and spinal cord injuries. Intraoral tongue drive system (iTDS) is one of the most feasible and non-invasive assistive technology (AT), which utilises the transferring and inferring of user intentions through different tongue gestures. Wireless transferring is of prime importance and requires a suitable design of the intra-oral antenna. In this paper, a compact circularly polarized differential intra-oral antenna is designed, and its performance is analysed within heterogeneous multilayer mouth and head models. It works at 2.4 GHz in the Industrial, Scientific, and Medical (ISM) band. The footprint of the differential antenna prototype is 0.271 λg [Formula: see text] 0.271 λg [Formula: see text] 0.015 λg. It is achieved using two pairs of spiral segments loaded in diagonal form near the edges of the central rotated square slot and a high dielectric constant substrate. Its spiral-slotted geometry further provides the desired swirling and miniaturization at the desired frequency band for both mouth scenarios. Additionally, corner triangular slits on the radiating patch assist in tuning the axial ratio (< 3 dB) in the desired ISM band. To validate the performance of the proposed in-mouth antenna, the measurement was carried out using the minced pork and the saline solution for closed and opened mouth cases, respectively. The measured - 10 dB impedance bandwidth and peak gain values in the minced pork are from 2.28 to 2.53 GHz (10.39%) and - 18.17 dBi, respectively, and in the saline solution, are from 2.3 to 2.54 GHz (9.92%) and - 15.47 dBi, respectively. Further, the specific absorption rate (SAR) is estimated, and the data communication link is computed with and without a balun loss. This confirms that the proposed differential intraoral antenna can establish direct interfacing at the RF front end of the intraoral tongue drive system.

Synthesis and Characterization of Nanostructured Oxide Layers on Ti-Nb-Zr-Ta and Ti-Nb-Zr-Fe Biomedical Alloys.

Nanoporous/nanotubular complex oxide layers were developed on high-fraction ß phase quaternary Ti-Nb-Zr-Ta and Ti-Nb-Zr-Fe promising biomedical alloys with a low elasticity modulus. Surface modification was achieved by electrochemical anodization aimed at the synthesis of the morphology of the nanostructures, which exhibited inner diameters of 15-100 nm. SEM, EDS, XRD, and current evolution analyses were performed for the characterization of the oxide layers. By optimizing the process parameters of electrochemical anodization, complex oxide layers with pore/tube openings of 18-92 nm on Ti-10Nb-10Zr-5Ta, 19-89 nm on Ti-20Nb-20Zr-4Ta, and 17-72 nm on Ti-29.3Nb-13.6Zr-1.9Fe alloys were synthesized using 1 M H3PO4 + 0.5 wt% HF aqueous electrolytes and 0.5 wt% NH4F + 2 wt% H20 + ethylene glycol organic electrolytes.

Amplifiers in Biomedical Engineering: A Review from Application Perspectives.

Continuous monitoring and treatment of various diseases with biomedical technologies and wearable electronics has become significantly important. The healthcare area is an important, evolving field that, among other things, requires electronic and micro-electromechanical technologies. Designed circuits and smart devices can lead to reduced hospitalization time and hospitals equipped with high-quality equipment. Some of these devices can also be implanted inside the body. Recently, various implanted electronic devices for monitoring and diagnosing diseases have been presented. These instruments require communication links through wireless technologies. In the transmitters of these devices, power amplifiers are the most important components and their performance plays important roles. This paper is devoted to collecting and providing a comprehensive review on the various designed implanted amplifiers for advanced biomedical applications. The reported amplifiers vary with respect to the class/type of amplifier, implemented CMOS technology, frequency band, output power, and the overall efficiency of the designs. The purpose of the authors is to provide a general view of the available solutions, and any researcher can obtain suitable circuit designs that can be selected for their problem by reading this survey.

Design of a Millimeter-Wave MIMO Antenna Array for 5G Communication Terminals.

This paper presents a design of multiple input multiple output (MIMO) antenna array for 5G millimeter-wave (mm-wave) communication systems. The proposed MIMO configuration consists of a two antenna arrays combination. Each antenna array consists of four elements which are arranged in an even manner, while two arrays are then assembled with a 90-degree shift with respect to each other. The substrate used is a 0.254 mm thick Rogers RT5880 with a dielectric constant of 2.2 and loss tangent of 0.0009, correspondingly. The proposed MIMO antenna array covers the 37 GHz frequency band, dedicated for 5G millimeter-wave communication applications. The proposed antenna element yields a gain of 6.84 dB, which is enhanced up to 12.8 dB by adopting a four elements array configuration. The proposed MIMO antenna array performance metrics, such as envelope correlation coefficient (ECC) and diversity gain (DG), are observed, which are found to be under the standard threshold. More than 85% of the radiation efficiency of the proposed MIMO antenna array is observed to be within the desired operating frequency band. All the proposed designs are simulated in computer simulation technology (CST) software. Furthermore, the measurements are carried out for the proposed MIMO antenna array, where a good agreement with simulated results is observed. Thus, the proposed design can be a potential candidate for 5G millimeter-wave communication systems.

In-Body Network Biomedical Applications: From Modeling to Experimentation.

Innovative diagnostic approaches and therapies are more and more based on the use of injections or oral delivery of nanoparticle sized substances. For a better understanding of the overall phenomena, aiming to facilitate a safe application at large scale, the development of accurate models and analysis techniques are required. These techniques take into consideration different aspects of the overall process: accurate numerical modeling of the different phases of the nanoparticles in the body, and knowledge of the local environment, that can be varying very fast within a short-range in the body itself. Such aspects should be taken into account to correctly predict the amount of drug and its timely release for the specific disease. Deep and accurate analysis of the interaction between the nanoparticles and the biological fluid where the nanoparticles are immersed is mandatory for an efficient correlation of all these aspects. Because of their biocompatibility, in this paper, we focus our attention on systems of Titanium (Ti), and its oxide (e.g., TiO2), given their specific features in terms of density, lack of cytotoxic effects, etc. Specifically, we present the study and design of an in-body system by characterizing each of the emission, diffusion, and reception processes with a proper realistic model. The theoretical investigation is further supported by experimental study of the morphology and other important characteristics (e.g., the pH of the particles, and thermal stability) of TiO2 systems when immersed in a Ringer solution, in order to derive important information related to their potential toxicity inside the human body.

A 10-year follow-up of ischemic heart disease risk factors in military pilots.

INTRODUCTION: Cardiovascular diseases (CVDs) represent the reason for approximately 10% of all groundings among military pilots. After their first screening examination, which decides their fitness for flight, pilots are required to appear for screening examinations yearly, which makes it possible to monitor the changes in the risk factors of ischemic heart disease (IHD) from their candidate days until their retirement or final grounding. SUBJECTS AND METHODS: During regular fitness screenings, we determined the individual and common occurrence and changes of recorded or measured IHD risk factors on the basis of 10- (baseline), 5-, and 0-year (current) data in the cases of 250 active male military pilots, broken down into 5-year age groups. In addition, by the help of complex risk calculation methods, we calculated the 5- and 10-year risk of coronary artery disease and CVDs, respectively. RESULTS: In the first year of the examinations, the following risk factors appeared: positive family history (25.0%), obesity (40.8%), smoking (31.7%), physical inactivity (23.9%), high blood pressure (14.7%), hypercholesterolemia (53.9%), pathological electrocardiogram deviations (1.3%). By aging, the occurrence of each risk factor remained unchanged or increased and their cumulative occurrence became more frequent, except for those above 45 to 50 yrs, who seldom had four or more risk factors at the same time. The cardiovascular risk calculated by the Futrex program was elevated in 40% of the study population (levels 3 and 4). By aging, the indices received by complex risk calculation methods deteriorated in the age group 25 to 45 years, while they improved in the age group of >45 years. The 5-year risk of CVDs was below 2.5% in half of the study population and it did not exceed 15 to 20% even in the age group with the highest risk. DISCUSSION: Based on reference data, pilots usually represent a healthier population in those countries where coronary artery diseases are leading health problems. In Hungary, many young pilots leave the army due to its currently ongoing transformation, while the elder are less motivated to change careers. It is probably the role of the stricter physical fitness test and screening examinations, and the effect of military propaganda targeting health conservation, that is in the background of the elder pilots' value improvements. It is also an influencing factor that by administering antilipid and antihypertensive medication based on NATO recommendations in the cases of those with increased risk, the probability of the development of IHD decreases and the affected pilots can be kept longer in service.