An Impedance-Based Catheter Positioning System for Cardiac Mapping and Navigation

Over the last years, nonfluoroscopic in vivo cardiac mapping and navigation systems have been developed and successfully applied in clinical electrophysiology. Clearly, a trend can be observed to introduce more sensors into the measurement system so that physiological information can be gathered simultaneously and more efficiently and the duration of procedure can be shortened significantly. However, it would not be realistic to equip each catheter electrode with a localizer, e.g., by embedding a miniature magnetic location sensor. Therefore, in this paper, an alternate approach has been worked out to efficiently localize multiple catheter electrodes by considering the impedance between electrodes in the heart and electrode patches on the body surface. In application of the new technique, no additional expensive and sophisticated hardware is required other than the currently existing cardiac navigation system. A tank model and a computerized realistic human model are employed to support the development of the positioning system. In the simulation study, the new approach achieves an average localization error of less than 1 mm, which proves the feasibility of the impedance-based catheter positioning system. Consequently, the new positioning system can provide an inexpensive and accurate solution to improve the efficiency and efficacy of catheter ablation.     

0.8 μW 12-bit SAR ADC sensors interface for RFID applications

The design and first measuring results of an ultra-low power 12 bit successive-approximation ADC for autonomous multi-sensor systems are presented. The comparator and the DAC are optmised for low power consumption. The power consumption is 0.52 μW from a 1.2 V supply with a sample clock of 3.125 kHz and 0.85 μW at 6.25 kHz. This gives 136 pJ per conversion or 66 fJ per conversion step. As per authors’ knowledge, 66 fJ per conversion step is the best reported so far.The ADC was realised in the NXP CMOS 0.14 μm technology; the area was 0.35 mm². Only four metal layers were used in order to allow 3D integration of the sensors.     

On the derivation of coupled-line models from EM simulators and application to MoM analysis

This paper addresses the problem of deriving an actual coupled-line model from the "spot frequency" characteristics of transmission media derived by means of a numerical electromagnetic simulator. For a given set of coupled lines, possibly asymmetric and lossy, one of the main issues is to recover a model whose parameters are physically and practically meaningful. In order to satisfy the requirements, the model ought to basically yield a natural generalization of the well-known even/odd and c//spl pi/ modes for couples of lines, and collapse to a set of uncoupled lines when coupling is negligible. Hence, part of this study is devoted to discussing and evaluating models that satisfy such requirements. The end result is a Weissfloch-type equivalent circuit made up of uncoupled lines and input and output ideal transformers. The algorithm is then applied to the network parameters of coupled lines. The latter are evaluated by a full-wave method of moments approach, and a subsequent short-open calibration (SOC) procedure. Finally, a new algorithm is introduced that is able to evaluate and remove the contribution of the naked discontinuity due to ports, usually not directly available from the SOC routine.     

In situ Characterization of SiO2 Nanoparticle Biointeractions Using BrightSilica

By adding a gold core to silica nanoparticles (BrightSilica), silica‐like nanoparticles are generated that, unlike unmodified silica nanoparticles, provide three types of complementary information to investigate the silica nano‐biointeraction inside eukaryotic cells in situ. Firstly, organic molecules in proximity of and penetrating into the silica shell in live cells are monitored by surface‐enhanced Raman scattering (SERS). The SERS data show interaction of the hybrid silica particles with tyrosine, cysteine and phenylalanine side chains of adsorbed proteins. Composition of the biomolecular corona of BrightSilica nanoparticles differs in fibroblast and macrophage cells. Secondly, quantification of the BrightSilica nanoparticles using laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) micromapping indicates a different interaction of silica nanoparticles compared to gold nanoparticles under the same experimental conditions. Thirdly, the metal cores allow the investigation of particle distribution and interaction in the cellular ultrastructure by cryo nanoscale X‐ray tomography (cryo‐XT). In 3D reconstructions the assumption is confirmed that BrightSilica nanoparticles enter cells by an endocytotic mechanism. The high SERS intensities are explained by the beneficial plasmonic properties due to agglomeration of BrightSilica. The results have implications for the development of multi‐modal qualitative and quantitative characterization in comparative nanotoxicology and bionanotechnology.     

Speed up of Video Enhancement based on Human Perception

This paper presents SUVEHP (speed up of video enhancement based on human perception), a human perception-based model oriented to reduce the computational time of digital video restoration. In particular, two specific hypothesis tests able to classify degraded frame regions are proposed. Classification is performed in agreement with regions visual significance in order to enable or inhibit motion compensated enhancement. The level of the proposed hypothesis tests is theoretically assessed. Moreover, extensive experimental results on video sequences affected by additive Gaussian noise show that SUVEHP speeds up some standard motion compensated denoisers up to 60%, preserving or even slightly increasing both the objective and subjective visual quality of the restored sequences.     

Determining the number of true different permutation polynomials of degrees up to five by Weng and Dong algorithm

Permutation polynomials (PPs) are used for interleavers in turbo codes, cryptography or sequence generation. The paper presents an algorithm for determining the number of true different PPs of degrees up to five. It is based on the algorithm from Weng and Dong (IEEE Trans Inf Theory 54(9):4388–4390, 2008) and on the null polynomials modulo the interleaver length.     

A fast and reliable technique for muscle activity detection from surface EMG signals

The estimation of on-off timing of human skeletal muscles during movement is an important issue in surface electromyography (EMG) signal processing with relevant clinical applications. In this paper, a novel approach to address this issue is proposed. The method is based on the identification of single motor unit action potentials from the surface EMG signal with the use of the continuous wavelet transform. A manifestation variable is computed as the maximum of the outputs of a bank of matched filters at different scales. A threshold is applied to the manifestation variable to detect EMG activity. A model, based on the physical structure of the muscle, is used to test the proposed technique on synthetic signals with known features. The resultant bias of the onset estimate is lower than 40 ms and the standard deviation lower than 30 ms in case of additive colored Gaussian noise with signal-to-noise ratio as low as 2 dB. Comparison with previously developed methods was performed, and representative applications to experimental signals are presented. The method is designed for a complete real-time implementation and, thus, may be applied in clinical routine activity.     

Stochastic stabilization for bilateral teleoperation over networks with probabilistic delays

This paper studies the bilateral teleoperation over communication networks. Specifically, the network-induced random delays are modeled as being from a finite set, each delay in the set having a probability of occurrence. To fully utilize the stochastic information inherent with the delays, a novel design scheme combining the probability information and pole placement is proposed to achieve better tracking performance. The teleoperation problem is first formulated as the stabilization of an error dynamic system where the error is the difference between the states of the master and slave. Then, by constructing a Lyapunov function, a sufficient condition to guarantee the input-to-state stability is established in terms of linear matrix inequalities. The simulation results and comparison show a decrease in tracking error with the new design method.     

Waterproof,Breathable, and Antibacterial Self‐Powered e‐Textiles Based on Omniphobic Triboelectric Nanogenerators

Multifunctional electronic textiles (e‐textiles) incorporating miniaturized electronic devices will pave the way toward a new generation of wearable devices and human–machine interfaces. Unfortunately, the development of e‐textiles is subject to critical challenges, such as battery dependence, breathability, satisfactory washability, and compatibility with mass production techniques. This work describes a simple and cost‐effective method to transform conventional garments and textiles into waterproof, breathable, and antibacterial e‐textiles for self‐powered human–machine interfacing. Combining embroidery with the spray‐based deposition of fluoroalkylated organosilanes and highly networked nanoflakes, omniphobic triboelectric nanogenerators (R^F‐TENGs) can be incorporated into any fiber‐based textile to power wearable devices using energy harvested from human motion. R^F‐TENGs are thin, flexible, breathable (air permeability 90.5 mm s^?1), inexpensive to fabricate (<0.04$ cm^?2), and capable of producing a high power density (600 µW cm^?2). E‐textiles based on R^F‐TENGs repel water, stains, and bacterial growth, and show excellent stability under mechanical deformations and remarkable washing durability under standard machine‐washing tests. Moreover, e‐textiles based on R^F‐TENGs are compatible with large‐scale production processes and exhibit high sensitivity to touch, enabling the cost‐effective manufacturing of wearable human–machine interfaces.     

Contact effects in organic thin-film transistor sensors

Contact effects in organic thin-film transistors (OTFTs) sensors are here investigated specifically respect to the gate field-induced sensitivity enhancement of more than three orders of magnitude seen in a DHα6T OTFT sensor exposed to 1-butanol vapors. This study shows that such a sensitivity enhancement effect is largely ascribable to changes occurring to the transistor channel resistance. Effects, such as the changes in contact resistance, are seen to influence the low gate voltage regime where the sensitivity is much lower.