236 research outputs found

    Novel non-invasive algorithm to identify the origins of re-entry and ectopic foci in the atria from 64-lead ECGs: A computational study.

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    Atrial tachy-arrhytmias, such as atrial fibrillation (AF), are characterised by irregular electrical activity in the atria, generally associated with erratic excitation underlain by re-entrant scroll waves, fibrillatory conduction of multiple wavelets or rapid focal activity. Epidemiological studies have shown an increase in AF prevalence in the developed world associated with an ageing society, highlighting the need for effective treatment options. Catheter ablation therapy, commonly used in the treatment of AF, requires spatial information on atrial electrical excitation. The standard 12-lead electrocardiogram (ECG) provides a method for non-invasive identification of the presence of arrhythmia, due to irregularity in the ECG signal associated with atrial activation compared to sinus rhythm, but has limitations in providing specific spatial information. There is therefore a pressing need to develop novel methods to identify and locate the origin of arrhythmic excitation. Invasive methods provide direct information on atrial activity, but may induce clinical complications. Non-invasive methods avoid such complications, but their development presents a greater challenge due to the non-direct nature of monitoring. Algorithms based on the ECG signals in multiple leads (e.g. a 64-lead vest) may provide a viable approach. In this study, we used a biophysically detailed model of the human atria and torso to investigate the correlation between the morphology of the ECG signals from a 64-lead vest and the location of the origin of rapid atrial excitation arising from rapid focal activity and/or re-entrant scroll waves. A focus-location algorithm was then constructed from this correlation. The algorithm had success rates of 93% and 76% for correctly identifying the origin of focal and re-entrant excitation with a spatial resolution of 40 mm, respectively. The general approach allows its application to any multi-lead ECG system. This represents a significant extension to our previously developed algorithms to predict the AF origins in association with focal activities

    Lanthanum(III)hydroxide Nanoparticles and Polyethyleneimine-Functionalized Graphene Quantum Dot Nanocomposites in Photosensitive Silicon Heterojunctions

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    Lanthanides are largely used in optoelectronics as dopants to enhance the physical and optical properties of semiconducting devices. In this study, lanthanum(III)hydroxide nanoparticles (La(OH)3NPs) are used as a dopant of polyethylenimine (PEI)-functionalized nitrogen (N)-doped graphene quantum dots (PEI-NGQDs). The La(OH)3NPs-dopedPEI-NGQDs nanocomposites are prepared from La(NO)3 in a single step by a green novel method and are characterized by Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Deposited over an n-type Si wafer, the La(OH)3NPs-dopedPEI-NGQDs nanocomposites form Schottky diodes. The I-V characteristics and the photoresponse of the diodes are investigated as a function of the illumination intensity in the range 0-110 mW cm-2 and at room temperature. It is found that the rectification ratio and ideality factor of the diode decrease, while the Schottky barrier and series resistance increase with the enhancing illuminations. As a photodetector, the La(OH)3NPs-dopedPEI-NGQDs/n-Si heterojunction exhibits an appreciable responsivity of 3.9 × 10-3 AW-1 under 22 mW cm-2 at −0.3 V bias and a maximum detectivity of 8.7 × 108 Jones under 22 mW cm-2 at −0.5 V. This study introduces the green synthesis and presents the structural, electrical, and optoelectronic properties of La(OH)3NPs-dopedPEI-NGQDs, demonstrating that these nanocomposites can be promising for optoelectronic applications

    Toxicity Assessment of Buprofezin, Lufenuron, and Triflumuron to the Earthworm Aporrectodea caliginosa

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    Earthworms are particularly important soil macroinvertebrates and are often used in assessing the general impact of pesticide pollution in soil. The present study was conducted in order to investigate the toxicity of three insect growth regulators (IGRs) buprofezin, lufenuron, and triflumuron, at different application rates and exposure times toward mature earthworms Aporrectodea caliginosa. The effects of these pesticides on the growth rate in relation to the activities of acetylcholinesterase (AChE) and glutathione S-transferase (GST) as biochemical indicators were evaluated to elucidate the mechanisms of action. Toxicity studies indicated that lufenuron was the most harmful pesticide to mature earthworms, followed in descending order by buprofezin and triflumuron. A reduction in growth rate in all pesticide-treated worms was dose-dependent over the 28-day exposure period, which was accompanied by a decrease in AChE and GST activities. Relationships between growth rate, AChE, and GST provided strong evidence for the involvement of pesticidal contamination in the biochemical changes in earthworms, which can be used as a bioindicator of soil contamination by pesticides

    The Latest Trends in Electric Vehicles Batteries

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    Global energy demand is rapidly increasing due to population and economic growth, especially in large emerging countries, which will account for 90% of energy demand growth to 2035. Electric vehicles (EVs) play a paramount role in the electrification revolution towards the reduction of the carbon footprint. Here, we review all the major trends in Li-ion batteries technologies used in EVs. We conclude that only five types of cathodes are used and that most of the EV companies use Nickel Manganese Cobalt oxide (NMC). Most of the Li-ion batteries anodes are graphite-based. Positive and negative electrodes are reviewed in detail as well as future trends such as the effort to reduce the Cobalt content. The electrolyte is a liquid/gel flammable solvent usually containing a LiFeP6 salt. The electrolyte makes the battery and battery pack unsafe, which drives the research and development to replace the flammable liquid by a solid electrolyte

    2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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    2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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