Albertsenstafford3131

For comparison, experiments were reproduced in-silico with FLUKA Monte Carlo (MC) simulations. Carbon ions provide iRADs with highest image quality in terms of normalized root mean square error, followed by helium ions and protons. All ions show similar capabilities of resolving WET for the considered phantoms, as shown by the similar average relative error less then 3%. Besides for the slab phantom, MC simulations yielded better results than the experiment, indicating potential improvement of the experimental setup. Our results showed that the ability to resolve the WET is similar for all particles, intrinsically limited by the granularity of the detector system. While carbon ions are best suited for acquiring iRADs with the investigated integration mode detector, helium ions are put forward as a less technical challenging alternative. Creative Commons Attribution license.We develop an atomistic model of a cerium dioxide CeO2nanoparticle, which we than extend our model to a ceria nanoparticle with a varied Ce3+/Ce4+composition. For a pure CeO2particle we compute the radial distribution function for all pairs of atoms in the nanoparticle, which we find in excellent agreement with the reported experimental data. For a particle with a mixed Ce3+/Ce4+we adjust the parameters and modify the crystallization procedure to produce a realistic distribution of Ce3+atoms on the particle. We improve our initial guess on the Lennard-Jones parameters by melting and recrystallizing the nanoparticle, as well as compute the radial distribution function for the nanoparticle at room temperature. © 2020 IOP Publishing Ltd.OBJECTIVE Photoplethysmography Imaging (PPGI) is a promising contactless camera-based method of non-invasive cardiovascular diagnostics. To achieve the best results, it is important to choose the most suitable camera for a specific application. The settings of the camera influence the quality of the detected signal. APPROACH The standard (EMVA 2016) for evaluating the imaging performance of machine vision cameras (MVC) helps at the initial decision of the sensor, but the camera should always be tested in terms of usability for a specific application. So far, PPGI lacks a standardized measurement scenario for evaluating the performance of individual cameras. For this, we realized a controllable optoelectronic phantom with artificial silicone skin allowing reproducible tests of cameras to verify their suitability for PPGI. The entire system is housed in a light-tight box. We tested an MVC, a digital single-lens reflex camera (DSLR) camera and a webcam. Each camera varies in used technology and price. MAIN RESUL Medicine.OBJECTIVE Premature beats (PB), typically presenting as premature ventricular contractions (PVC) and premature atrial contractions (PAC), may foreshadow stroke or sudden cardiac death. APPROACH A rule-based real-time PB detection system was proposed for timely diagnosis in an ambulatory setting and to reduce the cognitive load for physicians. The proposed method consists of three procedures (1) extraction of the RR interval, QRS complex template, width and height; (2) rough detection of PB candidates using rules corresponding to abnormality in rhythm and morphology; (3) refined detection using three types of correction. The method was trained using randomly selected single-lead waveforms sourced from the China Physiological Signal Challenge 2018 (CPSC2018) database, and the method was tested on the 12-lead CPSC2018 database, the MIT-BIH-AR database and the wearable ECG database. MAIN RESULTS Four quantitative parameters, namely sensitivity, positive predictive value, accuracy and F1 measure, were used to assess performance. The F1 measure for normal beats, PACs, and PVCs were 99.37, 90.6, and 90.85 % in training data (93.61 % across all beats). Vactosertib cell line The satisfactory results on 12-lead CPSC2018 database indicated the method had a good generalization ability between leads. Although the results on this MIT-BIH-AR database were not comparable with other methods, it showed stability in different testing database. In addition, the test results on wearable ECGs manifested that the method was robust and could provide a good algorithm basis for IoT applications. SIGNIFICANCE We have developed a rule-based method for real-time PB detection in single-lead ECG, which balances the computational complexity and recognition accuracy, indicating the clinical significance of the method. © 2020 Institute of Physics and Engineering in Medicine.OBJECTIVE Functional magnetic resonance imaging (fMRI) is commonly used to measure brain activity through the blood oxygen level dependent (BOLD) signal mechanism, but this only provides an indirect proxy signal to neuronal activity. Magnetoencephalography (MEG) provides a more direct measurement of the magnetic fields created by neuronal currents in the brain, but requires very specialized hardware and only measures these fields at the scalp. Recently, progress has been made to directly detect neuronal fields with MRI using the stimulus-induced rotary saturation (SIRS) effect, but interference from the BOLD response complicates such measurements. Here, we describe an approach to detect nanotesla-level, low-frequency alternating magnetic fields with an ultra-low field (ULF) MRI scanner, unaffected by the BOLD signal. APPROACH A steady-state implementation of the stimulus-induced rotary saturation (SIRS) method is developed. The method is designed to generate a significantly higher effect than previous SIRS-based methods as well as allowing for efficient signal averaging, giving a high contrast-to-noise ratio (CNR). The method is tested in computer simulations and in phantom scans. MAIN RESULTS The simulations and phantom scans demonstrated the ability of the method to measure magnetic fields at different frequencies at ULF with a stronger contrast than non-steady-state approaches. Furthermore, the rapid imaging functionality of the method reduced noise efficiently. The results demonstrated sufficient CNR down to 7 nT, but the sensitivity will depend on the imaging parameters. SIGNIFICANCE A steady-state SIRS method is able to detect low-frequency alternating magnetic fields at ultra-low main magnetic field strengths with a large signal response and contrast-to-noise, presenting an important step in sensing biological fields with ULF MRI. © 2020 IOP Publishing Ltd.