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The initial motivation for this work was to accomplish an easy way to manufacture different geometries of ultrasonic transducers and arrays using a PZT powder, combined with a standard process to have repetitive series of them. The piezoelectric thick film was obtained using a PZT paste and applying it by screen printing on an alumina substrate. Then, the film was drying and sintered with a temperature-time...
Biomedical signals are customarily overlaid with interferences and noise, furthermore, baseline wandering is another significant drawback to their accurate interpretation, especially if the implementation platform is a wheelchair. The nonlinear processes which generate the physiologic signals, and the disturbances, regularly exclude, or limit, the usage of classical linear techniques, hence, among...
Radio frequency identification technology is used to power a novel platform of sensor devices. The employed energy harvesting system of the individual sensors enables a blanking of the radio frequency field for a defined period, while supplying the sensor electronics with a highly stable voltage. This guarantees interference free operation of the electronic circuitry during measurements. The implementation...
Here we present a new technique to monitor dynamic conformational changes in voltage-sensitive membrane-bound proteins using radio frequency (RF) impedance measurements. Xenopus oocytes were transfected to express ShakerB-IR K+ ion channels, and step changes in membrane potential were applied using two-electrode voltage clamp (TEVC). Simultaneously, bipolar extracellular electrodes were used to measure...
The aim of this study is to develop a method for measuring the respiratory waveform using non-contact electrodes during bathing. To determine the most appropriate electrode arrangement, we modeled a composite system consisting of a body submerged in bath water. We calculated the frequency dependence of the impedance amplitude using a three-dimensional finite difference method (3D-FDM). The simulation...
A new drip infusion solution monitoring system has been developed for hospital and care facility use. The system detects the fall of each drip chamber drop of fluid and also a free-flow situation. Three non-contacting copper foil electrodes are used. The electrodes are wrapped around the infusion supply polyvinyl chloride (PVC) tube from the solution bag, the drip chamber, and the infusion PVC tube...
For the reduction of common-mode noise level in Indirect-contact ECG (IDC-ECG) measurement, a driven-right-leg grounding method was applied to the IDC-ECG. Because the IDC-ECG does not require any direct contact between the electrodes and the human skin, it is adequate for un-constraining long-term ECG measurement at home and its various applications are now under development. However, larger 60 Hz...
Radiofrequency (RF) ablation uses RF current to heat and kill cancer applied via an electrode inserted under image-guidance, and is in clinical use for tumors in liver, lung kidney, and bone. Mathematical models are frequently used to determine tissue temperature during RF ablation, but most prior models do not include accurate implementation of power control algorithms as are used in clinical devices...
Epilepsy affects nearly 3 million people in the United States alone. Given the fact that many people suffer from seizures that are intractable to pharmacological intervention, research groups are investigating the use of electrical stimulation to interact with and ameliorate symptoms of epileptic seizures. In mouse cortical slices made seizuregenic through chemical means, we applied precision controlled...
Successful management of cardiac heart failure requires a multifactorial approaching. It has been suggested that implantable hemodynamic long-term monitoring can improve patient care. This paper presents an analysis of the hemodynamic parameters commonly recorded, the most used implantable devices and their associated clinical trials. Newly implantable miniaturized sensors and devices are revisited...
We investigate on the use of the Domain Embedding Method (DEM) for the forward modelling in EIT. This approach is suitably configured to overcome the model meshing bottleneck since it does not require that the mesh on the domain is adapted to the boundary surface. This is of crucial importance for, e.g., clinical applications of EIT, as it avoids tedious and time-consuming (re-)meshing procedures...
Electrical Impedance Tomography (EIT) has been proposed as an alternative modality for breast imaging. Current EIT reconstruction algorithms are based in optimization procedures that aim to minimize the difference between the recorded data and a set of candidate scenarios. However, these methods produce images with diffused edges, as sharp structures are penalized by current regularization techniques...
This work is an assistive technology for people with visual disabilities and aims to facilitate access to written information in order to achieve better social inclusion and integration into work and educational activities. Two methods of electrical stimulation (by current and voltage) of the mechanoreceptors was tested to obtain tactile sensations on the fingertip. Current and voltage stimulation...
Electrical Bioimpedance (EBI) is one of the non-invasive monitoring technologies that could benefit from the emerging textile based measurement systems. If reliable and reproducible EBI measurements could be done with textile electrodes, that would facilitate the utilization of EBI-based personalized healthcare monitoring applications. In this work the performance of a custom-made dry-textile electrode...
Electronic bathroom scales are an easy-to-use, affordable mean to measure physiological parameters in addition to body weight. They have been proposed to obtain the ballistocardiogram (BCG) and derive from it the heart rate, cardiac output and systolic blood pressure. Therefore, weighing scales may suit intermittent monitoring in e-health and patient screening. Scales intended for bioelectrical impedance...
As wireless bio-medical long term monitoring moves towards personal monitoring it demands very high input impedance systems capable to extend the reading of bio-signal during the daily activities offering a kind of “stress free“, convenient connection, with no need for skin preparation. In particular we highlight the development and broad applications of our own circuits for wearable bio-potential...
This paper analyses the use of Electrical Impedance Spectroscopy (EIS) to efficiently monitor cryoprotectant concentrations in cryopreservation protocols. The proposed technique can improve methods such as Liquidus Tracking (LT), allowing vitrification without exposing tissues to damaging concentrations of cryoprotectant at relatively high temperatures, and avoiding rapid temperature changes. This...
Interest in the electrical modeling of the thorax is motivated by various desires ranging from determining cardiac function, optimizing defibrillation efficacy, monitoring pulmonary edema, etc. However, existing models represent the thorax with rather coarse anatomical details, limiting their utilizations for accurately simulating small electrodes which typically occurs in pacing and defibrillation...
Retinal prostheses are being developed to restore vision for the blind with retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Since neural prostheses depend upon electrical stimulation to control neural activity, optimal stimulation parameters for successful encoding of visual information are one of the most important requirements to enable visual perception...
The safety of transcranial magnetic stimulation (TMS) in patients with an implanted deep brain stimulation (DBS) systems has not been thoroughly investigated. One potential safety hazard is the induction of significant voltages in the subcutaneous leads in the scalp that could result in unintended electrical currents in the DBS electrode contacts. We measured ex-vivo the TMS-induced voltages and currents...
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