Displacement and strain are fundamental quantities that describe the normal and pathological mechanical function of soft biological materials. Non-invasive imaging techniques, including displacement-encoded magnetic resonance imaging (MRI), enable the direct calculation of biomaterial displacements during the application of extrinsic mechanical forces. However, because strain is derived from measured MRI-based displacements, data processing must be accomplished to minimise the propagation and amplification of errors. Here, we evaluate smoothing methods (including averaging filters, splines, finite impulse response filters and wavelets) that enable the calculation of strain in biomaterials from MRI-based displacements for minimal error, defined in terms of bias and precision. Displacement and strain precisions were improved using all smoothing methods studied. Precision generally increased with the number of smoothing iterations (i.e. repeated applications) of a chosen smoothing method. The bias depended on the smoothing method and tended to increase with the number of smoothing iterations. A Gaussian filter characterised complex and heterogeneous strain fields with maximum precision and minimum bias. The results suggest that the optimal choice of smoothing method to compute strain for a given biomaterial or tissue application depends on a careful consideration of trade-offs between the improved precision (with increased data smoothing) and the trending increase in bias.

It has been suggested that the wireless network evolution to smaller carrier wavelengths (from 2G to 5G) increases radio-frequency electromagnetic field (RF-EMF) absorption in Western Honey Bees (Apis mellifera). It is unknown whether the radiation performance of antennas is stable when an insect appears in their vicinity. In this research, the absorbed power in a worker honey bee and the influence of the bee's presence on antennas' radiation performance is investigated for the newly used frequencies in 5G networks, from 6-240 GHz. To these aims, numerical simulations using the finite-difference time-domain method were performed, in which a bee model, obtained by micro-CT scanning, was employed. These simulations showed that in the near field, the absorbed power can increase by a factor of 53, from 6-240 GHz. This is a factor of 7 higher than the increase reported in the far field, in previous studies. Furthermore, the simulations revealed that antennas' radiation efficiency can decrease by up to -40 % when a bee appears in the near field. Likewise, it was found that the gain pattern depends on the separation distance between the bee and the antenna, with a stronger dependency for higher frequencies.

A Register Transfer Level (RTL) design that integrates a figure-8 multi-band inductive link (MIL), a bi-level pulse harmonic modulation (PHM) system, and a Gallager A decoder is presented and verified. Integrating this MIL with a PHM system can lead to optimizing power efficiency, data rate, and transmitter power consumption in near field transcutaneous wireless communication systems for cortical implants (CI). Also, a technique to increase the data rate of PHM systems based in multi-level transmission (MLT) is presented. MLT is an attractive solution to increasing data rates in PHM systems while meeting power consumption constraints, since it does not require increasing the frequency of the harmonics generated in the PHM receiver. Verilog Analog Mixed Signal (AMS) was used to verify these systems. The distance between external and implanted coils was modeled to be 10 mm.From the power interference characterization of the bi-level system, it was observed that for every value of the coupling coefficient between the power transmitter coil and data receiver coil (k 14 ), there is a different comparator reference voltage that can minimize the bit error rate (BER) of the system and optimize decoder performance. Moreover, it is shown that as k 14 increases, this optimal reference voltage also increases. Therefore, it is expected that a control system that could adapt the comparator reference voltages to changes in (k 14 ), could enhance robustness of PHM systems against factors that can increase MIL power iv interference, such as misalignments. From the verification of the MLT technique, it was observed that the optimal delay between initiation and suppression pulses (t d ) of a PHM system varies with respect to initiation pulse amplitudes, contrary to what had been stated in the past in previous PHM system verifications. Furthermore, it is concluded that, unless the pulse pattern generator (PPG) is designed to vary t d according to the initiation pulse transmitted, MLT-based PHM systems would be too vulnerable to non-idealities, such as noise and misalignments, preventing its feasibility. From the transmitter (TX) clock jitter characterizations, it was concluded that as the PHM levels of transmission increase, systems become more sensitive to jitters. Finally, the Gallager A decoder was found powerful in enhancing the robustness of PHM systems against power interference, TX clock jitter, and noise. Cortical implants (CI) can be used in medicine to treat neurological disorders, and to serve as substitutes of damaged organs in the nervous system. Currently, active research is being developed in the wireless data and power transfer to CIs, in order to avoid frequent surgical interventions to replace batteries and potential paths of infection due to wires breaching the skin. In this paper, we consider performance optimization strategies for a pulse-based wireless link that have been proposed recently. We consider two enhancements that may allow for increased throughput in this system. First, a low-power error-correcting ...

Insects are exposed to environmental radio frequency electromagnetic fields (RF-EMFs), which are partially absorbed by their body. This absorption is currently unknown for most insect types. Therefore, numerical simulations were performed to study the far-field absorption of RF-EMFs by different insect types at the frequencies between 2 and 120 GHz, which are (expected to be) used in (future) wireless communication. The simulations were done using anatomically accurate as well as spheroid models of the insects. The maximum absorbed power, which ranged from 7.55 to 389 nW for an incident electric field strength of 1 V/m for the studied insect types, was obtained at wavelengths comparable to the insects' size. We created a log-linear model that can estimate absorbed power in insects with an average relative error of <43% between 6 and 120 GHz using only the insects' volume and the frequency as an input using the simulation results. In addition, our simulations showed a very high correlation (r > 0.95) between the absorbed power predicted with anatomically accurate insect models and those predicted with spheroid models at the frequencies between 6 and 24 GHz. This suggests that such models could be used to evaluate the RF-EMF exposure of insects in future studies.